Merge branch 'py2-cleanup' of https://github.com/eli-schwartz/calibre

setup/browser_data.py

@@ -9,7 +9,6 @@ import sys
 from datetime import datetime
 from urllib.request import urlopen
 
-from polyglot.builtins import filter
 from setup import download_securely
 
 

setup/translations.py

@@ -13,7 +13,7 @@ from functools import partial
 
 from setup import Command, __appname__, __version__, require_git_master, build_cache_dir, edit_file, dump_json
 from setup.parallel_build import batched_parallel_jobs
-from polyglot.builtins import codepoint_to_chr, iteritems, range
+from polyglot.builtins import codepoint_to_chr, iteritems
 is_ci = os.environ.get('CI', '').lower() == 'true'
 
 

src/calibre/__init__.py

@@ -1,11 +1,10 @@
-
 ''' E-book management software'''
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import sys, os, re, time, random, warnings
-from polyglot.builtins import codepoint_to_chr, unicode_type, range, hasenv, native_string_type
+from polyglot.builtins import codepoint_to_chr, hasenv, native_string_type
 from math import floor
 from functools import partial
 
@@ -13,7 +12,7 @@ if not hasenv('CALIBRE_SHOW_DEPRECATION_WARNINGS'):
     warnings.simplefilter('ignore', DeprecationWarning)
 try:
     os.getcwd()
-except EnvironmentError:
+except OSError:
     os.chdir(os.path.expanduser('~'))
 
 from calibre.constants import (iswindows, ismacos, islinux, isfrozen,
@@ -71,7 +70,7 @@ def get_types_map():
 
 
 def to_unicode(raw, encoding='utf-8', errors='strict'):
-    if isinstance(raw, unicode_type):
+    if isinstance(raw, str):
         return raw
     return raw.decode(encoding, errors)
 
@@ -259,7 +258,7 @@ def get_parsed_proxy(typ='http', debug=True):
                     traceback.print_exc()
             else:
                 if debug:
-                    prints('Using http proxy', unicode_type(ans))
+                    prints('Using http proxy', str(ans))
                 return ans
 
 
@@ -372,7 +371,7 @@ class CurrentDir:
     def __exit__(self, *args):
         try:
             os.chdir(self.cwd)
-        except EnvironmentError:
+        except OSError:
             # The previous CWD no longer exists
             pass
 
@@ -419,7 +418,7 @@ def strftime(fmt, t=None):
         fmt = fmt.decode('mbcs' if iswindows else 'utf-8', 'replace')
     ans = time.strftime(fmt, t)
     if early_year:
-        ans = ans.replace('_early year hack##', unicode_type(orig_year))
+        ans = ans.replace('_early year hack##', str(orig_year))
     return ans
 
 
@@ -531,7 +530,7 @@ def force_unicode(obj, enc=preferred_encoding):
 def as_unicode(obj, enc=preferred_encoding):
     if not isbytestring(obj):
         try:
-            obj = unicode_type(obj)
+            obj = str(obj)
         except Exception:
             try:
                 obj = native_string_type(obj)
@@ -554,7 +553,7 @@ def human_readable(size, sep=' '):
         if size < (1 << ((i + 1) * 10)):
             divisor, suffix = (1 << (i * 10)), candidate
             break
-    size = unicode_type(float(size)/divisor)
+    size = str(float(size)/divisor)
     if size.find(".") > -1:
         size = size[:size.find(".")+2]
     if size.endswith('.0'):

src/calibre/constants.py

@@ -1,12 +1,12 @@
 #!/usr/bin/env python
 # vim:fileencoding=utf-8
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
-from polyglot.builtins import map, unicode_type, environ_item, hasenv, getenv
+from polyglot.builtins import environ_item, hasenv
 import sys, locale, codecs, os, collections, collections.abc
 
 __appname__   = 'calibre'
 numeric_version = (5, 29, 0)
-__version__   = '.'.join(map(unicode_type, numeric_version))
+__version__   = '.'.join(map(str, numeric_version))
 git_version   = None
 __author__    = "Kovid Goyal <kovid@kovidgoyal.net>"
 
@@ -118,18 +118,18 @@ def _get_cache_dir():
     confcache = os.path.join(config_dir, 'caches')
     try:
         os.makedirs(confcache)
-    except EnvironmentError as err:
+    except OSError as err:
         if err.errno != errno.EEXIST:
             raise
     if isportable:
         return confcache
-    ccd = getenv('CALIBRE_CACHE_DIRECTORY')
+    ccd = os.getenv('CALIBRE_CACHE_DIRECTORY')
     if ccd is not None:
         ans = os.path.abspath(ccd)
         try:
             os.makedirs(ans)
             return ans
-        except EnvironmentError as err:
+        except OSError as err:
             if err.errno == errno.EEXIST:
                 return ans
 
@@ -141,7 +141,7 @@ def _get_cache_dir():
     elif ismacos:
         candidate = os.path.join(os.path.expanduser('~/Library/Caches'), __appname__)
     else:
-        candidate = getenv('XDG_CACHE_HOME', '~/.cache')
+        candidate = os.getenv('XDG_CACHE_HOME', '~/.cache')
         candidate = os.path.join(os.path.expanduser(candidate),
                                     __appname__)
         if isinstance(candidate, bytes):
@@ -151,7 +151,7 @@ def _get_cache_dir():
                 candidate = confcache
     try:
         os.makedirs(candidate)
-    except EnvironmentError as err:
+    except OSError as err:
         if err.errno != errno.EEXIST:
             candidate = confcache
     return candidate
@@ -340,7 +340,7 @@ if plugins is None:
 
 CONFIG_DIR_MODE = 0o700
 
-cconfd = getenv('CALIBRE_CONFIG_DIRECTORY')
+cconfd = os.getenv('CALIBRE_CONFIG_DIRECTORY')
 if cconfd is not None:
     config_dir = os.path.abspath(cconfd)
 elif iswindows:
@@ -354,7 +354,7 @@ elif iswindows:
 elif ismacos:
     config_dir = os.path.expanduser('~/Library/Preferences/calibre')
 else:
-    bdir = os.path.abspath(os.path.expanduser(getenv('XDG_CONFIG_HOME', '~/.config')))
+    bdir = os.path.abspath(os.path.expanduser(os.getenv('XDG_CONFIG_HOME', '~/.config')))
     config_dir = os.path.join(bdir, 'calibre')
     try:
         os.makedirs(config_dir, mode=CONFIG_DIR_MODE)
@@ -386,7 +386,7 @@ if getattr(sys, 'frozen', False):
     else:
         is_running_from_develop = running_in_develop_mode()
 
-in_develop_mode = getenv('CALIBRE_ENABLE_DEVELOP_MODE') == '1'
+in_develop_mode = os.getenv('CALIBRE_ENABLE_DEVELOP_MODE') == '1'
 
 
 def get_version():
@@ -415,7 +415,7 @@ def get_appname_for_display():
 def get_portable_base():
     'Return path to the directory that contains calibre-portable.exe or None'
     if isportable:
-        return os.path.dirname(os.path.dirname(getenv('CALIBRE_PORTABLE_BUILD')))
+        return os.path.dirname(os.path.dirname(os.getenv('CALIBRE_PORTABLE_BUILD')))
 
 
 def get_windows_username():

src/calibre/customize/__init__.py

@@ -1,4 +1,3 @@
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
@@ -6,7 +5,6 @@ import os, sys, zipfile, importlib, enum
 
 from calibre.constants import numeric_version, iswindows, ismacos
 from calibre.ptempfile import PersistentTemporaryFile
-from polyglot.builtins import unicode_type
 
 if iswindows:
     platform = 'windows'
@@ -207,7 +205,7 @@ class Plugin:  # {{{
             config_dialog.exec_()
 
             if config_dialog.result() == QDialog.DialogCode.Accepted:
-                sc = unicode_type(sc.text()).strip()
+                sc = str(sc.text()).strip()
                 customize_plugin(self, sc)
 
         geom = bytearray(config_dialog.saveGeometry())

src/calibre/customize/builtins.py

@@ -1814,7 +1814,7 @@ class StoreWeightlessBooksStore(StoreBase):
 class StoreWHSmithUKStore(StoreBase):
     name = 'WH Smith UK'
     author = 'Charles Haley'
-    description = u"Shop for savings on Books, discounted Magazine subscriptions and great prices on Stationery, Toys & Games"
+    description = "Shop for savings on Books, discounted Magazine subscriptions and great prices on Stationery, Toys & Games"
     actual_plugin = 'calibre.gui2.store.stores.whsmith_uk_plugin:WHSmithUKStore'
 
     headquarters = 'UK'

src/calibre/customize/conversion.py

@@ -7,7 +7,6 @@ import re, os, shutil, numbers
 
 from calibre import CurrentDir
 from calibre.customize import Plugin
-from polyglot.builtins import unicode_type
 
 
 class ConversionOption:
@@ -81,7 +80,7 @@ class OptionRecommendation:
                                                     self.option.choices:
             raise ValueError('OpRec: %s: Recommended value not in choices'%
                              self.option.name)
-        if not (isinstance(self.recommended_value, (numbers.Number, bytes, unicode_type)) or self.recommended_value is None):
+        if not (isinstance(self.recommended_value, (numbers.Number, bytes, str)) or self.recommended_value is None):
             raise ValueError('OpRec: %s:'%self.option.name + repr(
                 self.recommended_value) + ' is not a string or a number')
 
@@ -342,7 +341,7 @@ class OutputFormatPlugin(Plugin):
     @property
     def is_periodical(self):
         return self.oeb.metadata.publication_type and \
-            unicode_type(self.oeb.metadata.publication_type[0]).startswith('periodical:')
+            str(self.oeb.metadata.publication_type[0]).startswith('periodical:')
 
     def specialize_options(self, log, opts, input_fmt):
         '''

src/calibre/customize/profiles.py

@@ -5,7 +5,6 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 from calibre.customize import Plugin as _Plugin
-from polyglot.builtins import zip
 
 FONT_SIZES = [('xx-small', 1),
               ('x-small',  None),
@@ -32,8 +31,8 @@ class Plugin(_Plugin):
         self.fsizes = []
         for (name, num), size in zip(FONT_SIZES, fsizes):
             self.fsizes.append((name, num, float(size)))
-        self.fnames = dict((name, sz) for name, _, sz in self.fsizes if name)
+        self.fnames = {name: sz for name, _, sz in self.fsizes if name}
-        self.fnums = dict((num, sz) for _, num, sz in self.fsizes if num)
+        self.fnums = {num: sz for _, num, sz in self.fsizes if num}
         self.width_pts = self.width * 72./self.dpi
         self.height_pts = self.height * 72./self.dpi
 
@@ -487,7 +486,7 @@ class SonyReaderOutput(OutputProfile):
     dpi                       = 168.451
     fbase                     = 12
     fsizes                    = [7.5, 9, 10, 12, 15.5, 20, 22, 24]
-    unsupported_unicode_chars = [u'\u201f', u'\u201b']
+    unsupported_unicode_chars = ['\u201f', '\u201b']
 
     epub_periodical_format = 'sony'
     # periodical_date_in_title = False

src/calibre/customize/ui.py

@@ -1,4 +1,3 @@
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
@@ -22,7 +21,7 @@ from calibre.utils.config import (make_config_dir, Config, ConfigProxy,
                                  plugin_dir, OptionParser)
 from calibre.ebooks.metadata.sources.base import Source
 from calibre.constants import DEBUG, numeric_version, system_plugins_loc
-from polyglot.builtins import iteritems, itervalues, unicode_type
+from polyglot.builtins import iteritems, itervalues
 
 builtin_names = frozenset(p.name for p in builtin_plugins)
 BLACKLISTED_PLUGINS = frozenset({'Marvin XD', 'iOS reader applications'})
@@ -769,8 +768,7 @@ initialize_plugins()
 
 
 def initialized_plugins():
-    for plugin in _initialized_plugins:
+    yield from _initialized_plugins
-        yield plugin
 
 # }}}
 
@@ -781,12 +779,12 @@ def build_plugin(path):
     from calibre import prints
     from calibre.ptempfile import PersistentTemporaryFile
     from calibre.utils.zipfile import ZipFile, ZIP_STORED
-    path = unicode_type(path)
+    path = str(path)
     names = frozenset(os.listdir(path))
     if '__init__.py' not in names:
         prints(path, ' is not a valid plugin')
         raise SystemExit(1)
-    t = PersistentTemporaryFile(u'.zip')
+    t = PersistentTemporaryFile('.zip')
     with ZipFile(t, 'w', ZIP_STORED) as zf:
         zf.add_dir(path, simple_filter=lambda x:x in {'.git', '.bzr', '.svn', '.hg'})
     t.close()
@@ -852,7 +850,7 @@ def main(args=sys.argv):
         for plugin in initialized_plugins():
             type_len, name_len = max(type_len, len(plugin.type)), max(name_len, len(plugin.name))
         fmt = '%-{}s%-{}s%-15s%-15s%s'.format(type_len+1, name_len+1)
-        print(fmt%tuple(('Type|Name|Version|Disabled|Site Customization'.split('|'))))
+        print(fmt%tuple('Type|Name|Version|Disabled|Site Customization'.split('|')))
         print()
         for plugin in initialized_plugins():
             print(fmt%(

src/calibre/customize/zipplugin.py

@@ -22,7 +22,7 @@ from calibre import as_unicode
 from calibre.customize import (
     InvalidPlugin, Plugin, PluginNotFound, numeric_version, platform
 )
-from polyglot.builtins import itervalues, map, reload, string_or_bytes, unicode_type
+from polyglot.builtins import itervalues, reload, string_or_bytes
 
 # PEP 302 based plugin loading mechanism, works around the bug in zipimport in
 # python 2.x that prevents importing from zip files in locations whose paths
@@ -307,7 +307,7 @@ class CalibrePluginFinder:
             if ans.minimum_calibre_version > numeric_version:
                 raise InvalidPlugin(
                     'The plugin at %s needs a version of calibre >= %s' %
-                    (as_unicode(path_to_zip_file), '.'.join(map(unicode_type,
+                    (as_unicode(path_to_zip_file), '.'.join(map(str,
                         ans.minimum_calibre_version))))
 
             if platform not in ans.supported_platforms:
@@ -340,9 +340,9 @@ class CalibrePluginFinder:
                     break
         else:
             if self._identifier_pat.match(plugin_name) is None:
-                raise InvalidPlugin((
+                raise InvalidPlugin(
                     'The plugin at %r uses an invalid import name: %r' %
-                    (path_to_zip_file, plugin_name)))
+                    (path_to_zip_file, plugin_name))
 
         pynames = [x for x in names if x.endswith('.py')]
 

src/calibre/db/__init__.py

@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 SPOOL_SIZE = 30*1024*1024
 
 import numbers
-from polyglot.builtins import iteritems, range
+from polyglot.builtins import iteritems
 
 
 def _get_next_series_num_for_list(series_indices, unwrap=True):
@@ -77,10 +77,10 @@ def get_data_as_dict(self, prefix=None, authors_as_string=False, ids=None, conve
         prefix = backend.library_path
     fdata = backend.custom_column_num_map
 
-    FIELDS = set(['title', 'sort', 'authors', 'author_sort', 'publisher',
+    FIELDS = {'title', 'sort', 'authors', 'author_sort', 'publisher',
         'rating', 'timestamp', 'size', 'tags', 'comments', 'series',
         'series_index', 'uuid', 'pubdate', 'last_modified', 'identifiers',
-        'languages']).union(set(fdata))
+        'languages'}.union(set(fdata))
     for x, data in iteritems(fdata):
         if data['datatype'] == 'series':
             FIELDS.add('%d_index'%x)

src/calibre/db/adding.py

@@ -16,7 +16,7 @@ from calibre import prints
 from calibre.constants import filesystem_encoding, ismacos, iswindows
 from calibre.ebooks import BOOK_EXTENSIONS
 from calibre.utils.filenames import make_long_path_useable
-from polyglot.builtins import itervalues, map as it_map, unicode_type
+from polyglot.builtins import itervalues
 
 
 def splitext(path):
@@ -71,7 +71,7 @@ def metadata_extensions():
     # but not actually added)
     global _metadata_extensions
     if _metadata_extensions is None:
-        _metadata_extensions =  frozenset(it_map(unicode_type, BOOK_EXTENSIONS)) | {'opf'}
+        _metadata_extensions =  frozenset(BOOK_EXTENSIONS) | {'opf'}
     return _metadata_extensions
 
 
@@ -93,7 +93,7 @@ def listdir(root, sort_by_mtime=False):
         def safe_mtime(x):
             try:
                 return os.path.getmtime(x)
-            except EnvironmentError:
+            except OSError:
                 return time.time()
         items = sorted(items, key=safe_mtime)
 
@@ -146,7 +146,7 @@ def find_books_in_directory(dirpath, single_book_per_directory, compiled_rules=(
         for path in listdir_impl(dirpath, sort_by_mtime=True):
             key, ext = splitext(path)
             if allow_path(path, ext, compiled_rules):
-                books[icu_lower(key) if isinstance(key, unicode_type) else key.lower()][ext] = path
+                books[icu_lower(key) if isinstance(key, str) else key.lower()][ext] = path
 
         for formats in itervalues(books):
             if formats_ok(formats):
@@ -230,8 +230,7 @@ def cdb_find_in_dir(dirpath, single_book_per_directory, compiled_rules):
 def cdb_recursive_find(root, single_book_per_directory=True, compiled_rules=()):
     root = os.path.abspath(root)
     for dirpath in os.walk(root):
-        for formats in cdb_find_in_dir(dirpath[0], single_book_per_directory, compiled_rules):
+        yield from cdb_find_in_dir(dirpath[0], single_book_per_directory, compiled_rules)
-            yield formats
 
 
 def add_catalog(cache, path, title, dbapi=None):

src/calibre/db/backend.py

@@ -50,8 +50,7 @@ from calibre.utils.formatter_functions import (
 from calibre.utils.icu import sort_key
 from calibre.utils.img import save_cover_data_to
 from polyglot.builtins import (
-    cmp, iteritems, itervalues, native_string_type, reraise, string_or_bytes,
+    cmp, iteritems, itervalues, native_string_type, reraise, string_or_bytes
-    unicode_type
 )
 
 # }}}
@@ -108,7 +107,7 @@ class DBPrefs(dict):  # {{{
             dict.__setitem__(self, key, val)
 
     def raw_to_object(self, raw):
-        if not isinstance(raw, unicode_type):
+        if not isinstance(raw, str):
             raw = raw.decode(preferred_encoding)
         return json.loads(raw, object_hook=from_json)
 
@@ -152,18 +151,18 @@ class DBPrefs(dict):  # {{{
         self.__setitem__(key, val)
 
     def get_namespaced(self, namespace, key, default=None):
-        key = u'namespaced:%s:%s'%(namespace, key)
+        key = 'namespaced:%s:%s'%(namespace, key)
         try:
             return dict.__getitem__(self, key)
         except KeyError:
             return default
 
     def set_namespaced(self, namespace, key, val):
-        if u':' in key:
+        if ':' in key:
             raise KeyError('Colons are not allowed in keys')
-        if u':' in namespace:
+        if ':' in namespace:
             raise KeyError('Colons are not allowed in the namespace')
-        key = u'namespaced:%s:%s'%(namespace, key)
+        key = 'namespaced:%s:%s'%(namespace, key)
         self[key] = val
 
     def write_serialized(self, library_path):
@@ -262,7 +261,7 @@ def IdentifiersConcat():
     '''String concatenation aggregator for the identifiers map'''
 
     def step(ctxt, key, val):
-        ctxt.append(u'%s:%s'%(key, val))
+        ctxt.append('%s:%s'%(key, val))
 
     def finalize(ctxt):
         try:
@@ -352,7 +351,7 @@ class Connection(apsw.Connection):  # {{{
         self.createscalarfunction('title_sort', title_sort, 1)
         self.createscalarfunction('author_to_author_sort',
                 _author_to_author_sort, 1)
-        self.createscalarfunction('uuid4', lambda: unicode_type(uuid.uuid4()),
+        self.createscalarfunction('uuid4', lambda: str(uuid.uuid4()),
                 0)
 
         # Dummy functions for dynamically created filters
@@ -403,7 +402,7 @@ def set_global_state(backend):
 def rmtree_with_retry(path, sleep_time=1):
     try:
         shutil.rmtree(path)
-    except EnvironmentError as e:
+    except OSError as e:
         if e.errno == errno.ENOENT and not os.path.exists(path):
             return
         time.sleep(sleep_time)  # In case something has temporarily locked a file
@@ -646,10 +645,10 @@ class DB:
                 prints('found user category case overlap', catmap[uc])
                 cat = catmap[uc][0]
                 suffix = 1
-                while icu_lower((cat + unicode_type(suffix))) in catmap:
+                while icu_lower(cat + str(suffix)) in catmap:
                     suffix += 1
-                prints('Renaming user category %s to %s'%(cat, cat+unicode_type(suffix)))
+                prints('Renaming user category %s to %s'%(cat, cat+str(suffix)))
-                user_cats[cat + unicode_type(suffix)] = user_cats[cat]
+                user_cats[cat + str(suffix)] = user_cats[cat]
                 del user_cats[cat]
                 cats_changed = True
         if cats_changed:
@@ -755,25 +754,25 @@ class DB:
             if d['is_multiple']:
                 if x is None:
                     return []
-                if isinstance(x, (unicode_type, bytes)):
+                if isinstance(x, (str, bytes)):
                     x = x.split(d['multiple_seps']['ui_to_list'])
                 x = [y.strip() for y in x if y.strip()]
                 x = [y.decode(preferred_encoding, 'replace') if not isinstance(y,
-                    unicode_type) else y for y in x]
+                    str) else y for y in x]
-                return [u' '.join(y.split()) for y in x]
+                return [' '.join(y.split()) for y in x]
             else:
-                return x if x is None or isinstance(x, unicode_type) else \
+                return x if x is None or isinstance(x, str) else \
                         x.decode(preferred_encoding, 'replace')
 
         def adapt_datetime(x, d):
-            if isinstance(x, (unicode_type, bytes)):
+            if isinstance(x, (str, bytes)):
                 if isinstance(x, bytes):
                     x = x.decode(preferred_encoding, 'replace')
                 x = parse_date(x, assume_utc=False, as_utc=False)
             return x
 
         def adapt_bool(x, d):
-            if isinstance(x, (unicode_type, bytes)):
+            if isinstance(x, (str, bytes)):
                 if isinstance(x, bytes):
                     x = x.decode(preferred_encoding, 'replace')
                 x = x.lower()
@@ -796,7 +795,7 @@ class DB:
         def adapt_number(x, d):
             if x is None:
                 return None
-            if isinstance(x, (unicode_type, bytes)):
+            if isinstance(x, (str, bytes)):
                 if isinstance(x, bytes):
                     x = x.decode(preferred_encoding, 'replace')
                 if x.lower() == 'none':
@@ -825,7 +824,7 @@ class DB:
             else:
                 is_category = False
             is_m = v['multiple_seps']
-            tn = 'custom_column_{0}'.format(v['num'])
+            tn = 'custom_column_{}'.format(v['num'])
             self.field_metadata.add_custom_field(label=v['label'],
                     table=tn, column='value', datatype=v['datatype'],
                     colnum=v['num'], name=v['name'], display=v['display'],
@@ -888,7 +887,7 @@ class DB:
                 # account for the series index column. Field_metadata knows that
                 # the series index is one larger than the series. If you change
                 # it here, be sure to change it there as well.
-                self.FIELD_MAP[unicode_type(data['num'])+'_index'] = base = base+1
+                self.FIELD_MAP[str(data['num'])+'_index'] = base = base+1
                 self.field_metadata.set_field_record_index(label_+'_index', base,
                             prefer_custom=True)
 
@@ -1311,7 +1310,7 @@ class DB:
         if getattr(self, '_library_id_', None) is None:
             ans = self.conn.get('SELECT uuid FROM library_id', all=False)
             if ans is None:
-                ans = unicode_type(uuid.uuid4())
+                ans = str(uuid.uuid4())
                 self.library_id = ans
             else:
                 self._library_id_ = ans
@@ -1319,7 +1318,7 @@ class DB:
 
     @library_id.setter
     def library_id(self, val):
-        self._library_id_ = unicode_type(val)
+        self._library_id_ = str(val)
         self.execute('''
                 DELETE FROM library_id;
                 INSERT INTO library_id (uuid) VALUES (?);
@@ -1429,7 +1428,7 @@ class DB:
         path = os.path.abspath(os.path.join(self.library_path, path, 'cover.jpg'))
         try:
             return utcfromtimestamp(os.stat(path).st_mtime)
-        except EnvironmentError:
+        except OSError:
             pass  # Cover doesn't exist
 
     def copy_cover_to(self, path, dest, windows_atomic_move=None, use_hardlink=False, report_file_size=None):
@@ -1445,11 +1444,11 @@ class DB:
             if os.access(path, os.R_OK):
                 try:
                     f = lopen(path, 'rb')
-                except (IOError, OSError):
+                except OSError:
                     time.sleep(0.2)
                     try:
                         f = lopen(path, 'rb')
-                    except (IOError, OSError) as e:
+                    except OSError as e:
                         # Ensure the path that caused this error is reported
                         raise Exception('Failed to open %r with error: %s' % (path, e))
 
@@ -1479,13 +1478,13 @@ class DB:
         path = os.path.abspath(os.path.join(self.library_path, path, 'cover.jpg'))
         try:
             stat = os.stat(path)
-        except EnvironmentError:
+        except OSError:
             return False, None, None
         if abs(timestamp - stat.st_mtime) < 0.1:
             return True, None, None
         try:
             f = lopen(path, 'rb')
-        except (IOError, OSError):
+        except OSError:
             time.sleep(0.2)
         f = lopen(path, 'rb')
         with f:
@@ -1520,7 +1519,7 @@ class DB:
             if os.path.exists(path):
                 try:
                     os.remove(path)
-                except (IOError, OSError):
+                except OSError:
                     time.sleep(0.2)
                     os.remove(path)
         else:
@@ -1530,7 +1529,7 @@ class DB:
             else:
                 try:
                     save_cover_data_to(data, path)
-                except (IOError, OSError):
+                except OSError:
                     time.sleep(0.2)
                     save_cover_data_to(data, path)
 
@@ -1616,7 +1615,7 @@ class DB:
                     # wrong in the rest of this function, at least the file is
                     # not deleted
                     os.rename(old_path, dest)
-                except EnvironmentError as e:
+                except OSError as e:
                     if getattr(e, 'errno', None) != errno.ENOENT:
                         # Failing to rename the old format will at worst leave a
                         # harmless orphan, so log and ignore the error
@@ -1728,11 +1727,11 @@ class DB:
         try:
             with lopen(path, 'wb') as f:
                 f.write(raw)
-        except EnvironmentError:
+        except OSError:
             exc_info = sys.exc_info()
             try:
                 os.makedirs(os.path.dirname(path))
-            except EnvironmentError as err:
+            except OSError as err:
                 if err.errno == errno.EEXIST:
                     # Parent directory already exists, re-raise original exception
                     reraise(*exc_info)
@@ -1811,8 +1810,7 @@ class DB:
         return frozenset(r[0] for r in self.execute('SELECT book FROM books_plugin_data WHERE name=?', (name,)))
 
     def annotations_for_book(self, book_id, fmt, user_type, user):
-        for x in annotations_for_book(self.conn, book_id, fmt, user_type, user):
+        yield from annotations_for_book(self.conn, book_id, fmt, user_type, user)
-            yield x
 
     def search_annotations(self,
         fts_engine_query, use_stemming, highlight_start, highlight_end, snippet_size, annotation_type,
@@ -2026,7 +2024,7 @@ class DB:
         def map_data(x):
             if not isinstance(x, string_or_bytes):
                 x = native_string_type(x)
-            x = x.encode('utf-8') if isinstance(x, unicode_type) else x
+            x = x.encode('utf-8') if isinstance(x, str) else x
             x = pickle_binary_string(x)
             return x
         options = [(book_id, fmt.upper(), map_data(data)) for book_id, data in iteritems(options)]
@@ -2067,7 +2065,7 @@ class DB:
                 copyfile_using_links(src, dest, dest_is_dir=False)
                 old_files.add(src)
             x = path_map[x]
-            if not isinstance(x, unicode_type):
+            if not isinstance(x, str):
                 x = x.decode(filesystem_encoding, 'replace')
             progress(x, i+1, total)
 
@@ -2081,18 +2079,18 @@ class DB:
         for loc in old_dirs:
             try:
                 rmtree_with_retry(loc)
-            except EnvironmentError as e:
+            except OSError as e:
                 if os.path.exists(loc):
                     prints('Failed to delete:', loc, 'with error:', as_unicode(e))
         for loc in old_files:
             try:
                 os.remove(loc)
-            except EnvironmentError as e:
+            except OSError as e:
                 if e.errno != errno.ENOENT:
                     prints('Failed to delete:', loc, 'with error:', as_unicode(e))
         try:
             os.rmdir(odir)
-        except EnvironmentError:
+        except OSError:
             pass
         self.conn  # Connect to the moved metadata.db
         progress(_('Completed'), total, total)

src/calibre/db/cache.py

@@ -47,9 +47,7 @@ from calibre.utils.config import prefs, tweaks
 from calibre.utils.date import UNDEFINED_DATE, now as nowf, utcnow
 from calibre.utils.icu import sort_key
 from calibre.utils.localization import canonicalize_lang
-from polyglot.builtins import (
+from polyglot.builtins import cmp, iteritems, itervalues, string_or_bytes
-    cmp, iteritems, itervalues, string_or_bytes, unicode_type, zip
-)
 
 
 def api(f):
@@ -581,14 +579,14 @@ class Cache:
     @read_api
     def get_item_id(self, field, item_name):
         ' Return the item id for item_name (case-insensitive) '
-        rmap = {icu_lower(v) if isinstance(v, unicode_type) else v:k for k, v in iteritems(self.fields[field].table.id_map)}
+        rmap = {icu_lower(v) if isinstance(v, str) else v:k for k, v in iteritems(self.fields[field].table.id_map)}
-        return rmap.get(icu_lower(item_name) if isinstance(item_name, unicode_type) else item_name, None)
+        return rmap.get(icu_lower(item_name) if isinstance(item_name, str) else item_name, None)
 
     @read_api
     def get_item_ids(self, field, item_names):
         ' Return the item id for item_name (case-insensitive) '
-        rmap = {icu_lower(v) if isinstance(v, unicode_type) else v:k for k, v in iteritems(self.fields[field].table.id_map)}
+        rmap = {icu_lower(v) if isinstance(v, str) else v:k for k, v in iteritems(self.fields[field].table.id_map)}
-        return {name:rmap.get(icu_lower(name) if isinstance(name, unicode_type) else name, None) for name in item_names}
+        return {name:rmap.get(icu_lower(name) if isinstance(name, str) else name, None) for name in item_names}
 
     @read_api
     def author_data(self, author_ids=None):
@@ -1329,7 +1327,7 @@ class Cache:
 
         try:
             return self.backend.read_backup(path)
-        except EnvironmentError:
+        except OSError:
             return None
 
     @write_api

src/calibre/db/categories.py

@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import copy
 from functools import partial
-from polyglot.builtins import iteritems, unicode_type, map, native_string_type
+from polyglot.builtins import iteritems, native_string_type
 
 from calibre.ebooks.metadata import author_to_author_sort
 from calibre.utils.config_base import tweaks
@@ -44,7 +44,7 @@ class Tag:
 
     @property
     def string_representation(self):
-        return u'%s:%s:%s:%s:%s'%(self.name, self.count, self.id, self.state, self.category)
+        return '%s:%s:%s:%s:%s'%(self.name, self.count, self.id, self.state, self.category)
 
     def __str__(self):
         return self.string_representation
@@ -101,8 +101,8 @@ def clean_user_categories(dbcache):
         if len(comps) == 0:
             i = 1
             while True:
-                if unicode_type(i) not in user_cats:
+                if str(i) not in user_cats:
-                    new_cats[unicode_type(i)] = user_cats[k]
+                    new_cats[str(i)] = user_cats[k]
                     break
                 i += 1
         else:

src/calibre/db/cli/cmd_add.py

@@ -21,7 +21,6 @@ from calibre.ptempfile import TemporaryDirectory
 from calibre.srv.changes import books_added, formats_added
 from calibre.utils.localization import canonicalize_lang
 from calibre.utils.short_uuid import uuid4
-from polyglot.builtins import unicode_type
 
 readonly = False
 version = 0  # change this if you change signature of implementation()
@@ -264,7 +263,7 @@ def do_add(
                                 try:
                                     with lopen(mi.cover, 'rb') as f:
                                         cover_data = f.read()
-                                except EnvironmentError:
+                                except OSError:
                                     pass
 
                 book_title, ids, mids, dups = dbctx.run(
@@ -296,9 +295,9 @@ def do_add(
                     prints('   ', path)
 
         if added_ids:
-            prints(_('Added book ids: %s') % (', '.join(map(unicode_type, added_ids))))
+            prints(_('Added book ids: %s') % (', '.join(map(str, added_ids))))
         if merged_ids:
-            prints(_('Merged book ids: %s') % (', '.join(map(unicode_type, merged_ids))))
+            prints(_('Merged book ids: %s') % (', '.join(map(str, merged_ids))))
 
 
 def option_parser(get_parser, args):
@@ -463,8 +462,8 @@ def main(opts, args, dbctx):
     lcodes = [canonicalize_lang(x) for x in (opts.languages or '').split(',')]
     lcodes = [x for x in lcodes if x]
     identifiers = (x.partition(':')[::2] for x in opts.identifier)
-    identifiers = dict((k.strip(), v.strip()) for k, v in identifiers
+    identifiers = {k.strip(): v.strip() for k, v in identifiers
-                       if k.strip() and v.strip())
+                       if k.strip() and v.strip()}
     if opts.empty:
         do_add_empty(
             dbctx, opts.title, aut, opts.isbn, tags, opts.series, opts.series_index,

src/calibre/db/cli/cmd_backup_metadata.py

@@ -54,7 +54,7 @@ class BackupProgress:
         else:
             self.count += 1
             prints(
-                u'%.1f%% %s - %s' % ((self.count * 100) / float(self.total), book_id,
+                '%.1f%% %s - %s' % ((self.count * 100) / float(self.total), book_id,
                                      getattr(mi, 'title', 'Unknown'))
             )
 

src/calibre/db/cli/cmd_list.py

@@ -11,7 +11,7 @@ from textwrap import TextWrapper
 from calibre.db.cli.utils import str_width
 from calibre.ebooks.metadata import authors_to_string
 from calibre.utils.date import isoformat
-from polyglot.builtins import as_bytes, iteritems, map, unicode_type
+from polyglot.builtins import as_bytes, iteritems
 
 readonly = True
 version = 0  # change this if you change signature of implementation()
@@ -123,10 +123,10 @@ def prepare_output_table(fields, book_ids, data, metadata):
         ans.append(row)
         for field in fields:
             if field == 'id':
-                row.append(unicode_type(book_id))
+                row.append(str(book_id))
                 continue
             val = data.get(field.replace('*', '#'), {}).get(book_id)
-            row.append(unicode_type(val).replace('\n', ' '))
+            row.append(str(val).replace('\n', ' '))
     return ans
 
 
@@ -308,7 +308,7 @@ List the books available in the calibre database.
 def main(opts, args, dbctx):
     afields = set(FIELDS) | {'id'}
     if opts.fields.strip():
-        fields = [unicode_type(f.strip().lower()) for f in opts.fields.split(',')]
+        fields = [str(f.strip().lower()) for f in opts.fields.split(',')]
     else:
         fields = []
 

src/calibre/db/cli/cmd_list_categories.py

@@ -8,7 +8,7 @@ import sys
 from textwrap import TextWrapper
 
 from calibre import prints
-from polyglot.builtins import as_bytes, map, unicode_type
+from polyglot.builtins import as_bytes
 
 readonly = True
 version = 0  # change this if you change signature of implementation()
@@ -78,7 +78,7 @@ def do_list(fields, data, opts):
     widths = list(map(lambda x: 0, fields))
     for i in data:
         for j, field in enumerate(fields):
-            widths[j] = max(widths[j], max(len(field), len(unicode_type(i[field]))))
+            widths[j] = max(widths[j], max(len(field), len(str(i[field]))))
 
     screen_width = geometry()[0]
     if not screen_width:
@@ -109,7 +109,7 @@ def do_list(fields, data, opts):
 
     for record in data:
         text = [
-            wrappers[i].wrap(unicode_type(record[field]))
+            wrappers[i].wrap(str(record[field]))
             for i, field in enumerate(fields)
         ]
         lines = max(map(len, text))
@@ -167,11 +167,11 @@ def main(opts, args, dbctx):
             is_rating = category_metadata(category)['datatype'] == 'rating'
             for tag in category_data[category]:
                 if is_rating:
-                    tag.name = unicode_type(len(tag.name))
+                    tag.name = str(len(tag.name))
                 data.append({
                     'category': category,
                     'tag_name': tag.name,
-                    'count': unicode_type(tag.count),
+                    'count': str(tag.count),
                     'rating': fmtr(tag.avg_rating),
                 })
     else:
@@ -179,7 +179,7 @@ def main(opts, args, dbctx):
             data.append({
                 'category': category,
                 'tag_name': _('CATEGORY ITEMS'),
-                'count': unicode_type(len(category_data[category])),
+                'count': str(len(category_data[category])),
                 'rating': ''
             })
 

src/calibre/db/cli/cmd_remove_custom_column.py

@@ -6,7 +6,6 @@
 import sys
 from calibre import prints
 from calibre.db.legacy import LibraryDatabase
-from polyglot.builtins import raw_input
 
 readonly = False
 version = 0  # change this if you change signature of implementation()
@@ -39,7 +38,7 @@ columns with the custom_columns command.
 
 
 def input_unicode(prompt):
-    ans = raw_input(prompt)
+    ans = input(prompt)
     if isinstance(ans, bytes):
         ans = ans.decode(sys.stdin.encoding)
     return ans

src/calibre/db/cli/cmd_set_metadata.py

@@ -10,7 +10,7 @@ from calibre.ebooks.metadata.book.base import field_from_string
 from calibre.ebooks.metadata.book.serialize import read_cover
 from calibre.ebooks.metadata.opf import get_metadata
 from calibre.srv.changes import metadata
-from polyglot.builtins import iteritems, unicode_type, getcwd
+from polyglot.builtins import iteritems
 
 readonly = False
 version = 0  # change this if you change signature of implementation()
@@ -147,7 +147,7 @@ def main(opts, args, dbctx):
         with lopen(opf, 'rb') as stream:
             mi = get_metadata(stream)[0]
         if mi.cover:
-            mi.cover = os.path.join(os.path.dirname(opf), os.path.relpath(mi.cover, getcwd()))
+            mi.cover = os.path.join(os.path.dirname(opf), os.path.relpath(mi.cover, os.getcwd()))
         final_mi = dbctx.run('set_metadata', 'opf', book_id, read_cover(mi))
         if not final_mi:
             raise SystemExit(_('No book with id: %s in the database') % book_id)
@@ -181,5 +181,5 @@ def main(opts, args, dbctx):
         if not final_mi:
             raise SystemExit(_('No book with id: %s in the database') % book_id)
 
-    prints(unicode_type(final_mi))
+    prints(str(final_mi))
     return 0

src/calibre/db/cli/cmd_show_metadata.py

@@ -3,11 +3,11 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 
+import os
 import sys
 
 from calibre import prints
 from calibre.ebooks.metadata.opf2 import OPFCreator
-from polyglot.builtins import unicode_type, getcwd
 
 readonly = True
 version = 0  # change this if you change signature of implementation()
@@ -49,9 +49,9 @@ def main(opts, args, dbctx):
         raise SystemExit('Id #%d is not present in database.' % id)
     if opts.as_opf:
         stdout = getattr(sys.stdout, 'buffer', sys.stdout)
-        mi = OPFCreator(getcwd(), mi)
+        mi = OPFCreator(os.getcwd(), mi)
         mi.render(stdout)
     else:
-        prints(unicode_type(mi))
+        prints(str(mi))
 
     return 0

src/calibre/db/cli/utils.py

@@ -3,8 +3,6 @@
 # License: GPLv3 Copyright: 2017, Kovid Goyal <kovid at kovidgoyal.net>
 
 
-from polyglot.builtins import map
-
 import unicodedata
 
 eaw = unicodedata.east_asian_width

src/calibre/db/delete_service.py

@@ -88,7 +88,7 @@ class DeleteService(Thread):
                     basename = '%d - %s' % (c, os.path.basename(path))
                 try:
                     shutil.move(path, dest)
-                except EnvironmentError:
+                except OSError:
                     if os.path.isdir(path):
                         # shutil.move may have partially copied the directory,
                         # so the subsequent call to move() will fail as the

src/calibre/db/fields.py

@@ -18,7 +18,7 @@ from calibre.utils.config_base import tweaks
 from calibre.utils.icu import sort_key
 from calibre.utils.date import UNDEFINED_DATE, clean_date_for_sort, parse_date
 from calibre.utils.localization import calibre_langcode_to_name
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems
 
 
 def bool_sort_key(bools_are_tristate):
@@ -85,7 +85,7 @@ class Field:
             self._sort_key = lambda x: sort_key(author_to_author_sort(x))
             self.sort_sort_key = False
         self.default_value = {} if name == 'identifiers' else () if self.is_multiple else None
-        self.category_formatter = unicode_type
+        self.category_formatter = str
         if dt == 'rating':
             if self.metadata['display'].get('allow_half_stars', False):
                 self.category_formatter = lambda x: rating_to_stars(x, True)
@@ -328,8 +328,7 @@ class CompositeField(OneToOneField):
             for v in vals:
                 if v:
                     val_map[v].add(book_id)
-        for val, book_ids in iteritems(val_map):
+        yield from iteritems(val_map)
-            yield val, book_ids
 
     def iter_counts(self, candidates, get_metadata=None):
         val_map = defaultdict(set)
@@ -343,8 +342,7 @@ class CompositeField(OneToOneField):
             else:
                 length = 0
             val_map[length].add(book_id)
-        for val, book_ids in iteritems(val_map):
+        yield from iteritems(val_map)
-            yield val, book_ids
 
     def get_composite_categories(self, tag_class, book_rating_map, book_ids,
                                  is_multiple, get_metadata):
@@ -437,8 +435,7 @@ class OnDeviceField(OneToOneField):
         val_map = defaultdict(set)
         for book_id in candidates:
             val_map[self.for_book(book_id, default_value=default_value)].add(book_id)
-        for val, book_ids in iteritems(val_map):
+        yield from iteritems(val_map)
-            yield val, book_ids
 
 
 class LazySortMap:
@@ -562,8 +559,7 @@ class ManyToManyField(Field):
         cbm = self.table.book_col_map
         for book_id in candidates:
             val_map[len(cbm.get(book_id, ()))].add(book_id)
-        for count, book_ids in iteritems(val_map):
+        yield from iteritems(val_map)
-            yield count, book_ids
 
     @property
     def book_value_map(self):

src/calibre/db/lazy.py

@@ -14,7 +14,7 @@ from copy import deepcopy
 from calibre.ebooks.metadata.book.base import Metadata, SIMPLE_GET, TOP_LEVEL_IDENTIFIERS, NULL_VALUES, ALL_METADATA_FIELDS
 from calibre.ebooks.metadata.book.formatter import SafeFormat
 from calibre.utils.date import utcnow
-from polyglot.builtins import unicode_type, native_string_type
+from polyglot.builtins import native_string_type
 
 # Lazy format metadata retrieval {{{
 '''
@@ -46,7 +46,7 @@ class MutableBase:
 
     @resolved
     def __unicode__(self):
-        return unicode_type(self._values)
+        return str(self._values)
 
     @resolved
     def __len__(self):

src/calibre/db/legacy.py

@@ -6,7 +6,7 @@ __license__ = 'GPL v3'
 __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os, traceback, weakref
-from polyglot.builtins import iteritems, zip
+from polyglot.builtins import iteritems
 from collections.abc import MutableMapping
 
 from calibre import force_unicode, isbytestring
@@ -29,7 +29,7 @@ def cleanup_tags(tags):
     tags = [x.strip().replace(',', ';') for x in tags if x.strip()]
     tags = [x.decode(preferred_encoding, 'replace')
                 if isbytestring(x) else x for x in tags]
-    tags = [u' '.join(x.split()) for x in tags]
+    tags = [' '.join(x.split()) for x in tags]
     ans, seen = [], set()
     for tag in tags:
         if tag.lower() not in seen:
@@ -684,8 +684,7 @@ class LibraryDatabase:
         self.new_api.refresh_ondevice()
 
     def tags_older_than(self, tag, delta, must_have_tag=None, must_have_authors=None):
-        for book_id in sorted(self.new_api.tags_older_than(tag, delta=delta, must_have_tag=must_have_tag, must_have_authors=must_have_authors)):
+        yield from sorted(self.new_api.tags_older_than(tag, delta=delta, must_have_tag=must_have_tag, must_have_authors=must_have_authors))
-            yield book_id
 
     def sizeof_format(self, index, fmt, index_is_id=False):
         book_id = index if index_is_id else self.id(index)
@@ -848,8 +847,7 @@ class LibraryDatabase:
 
     # Private interface {{{
     def __iter__(self):
-        for row in self.data.iterall():
+        yield from self.data.iterall()
-            yield row
 
     def _get_next_series_num_for_list(self, series_indices):
         return _get_next_series_num_for_list(series_indices)

src/calibre/db/restore.py

@@ -17,7 +17,7 @@ from calibre.db.cache import Cache
 from calibre.constants import filesystem_encoding
 from calibre.utils.date import utcfromtimestamp
 from calibre import isbytestring, force_unicode
-from polyglot.builtins import iteritems, filter
+from polyglot.builtins import iteritems
 
 NON_EBOOK_EXTENSIONS = frozenset((
     'jpg', 'jpeg', 'gif', 'png', 'bmp',
@@ -42,7 +42,7 @@ class Restorer(Cache):
 class Restore(Thread):
 
     def __init__(self, library_path, progress_callback=None):
-        super(Restore, self).__init__()
+        super().__init__()
         if isbytestring(library_path):
             library_path = library_path.decode(filesystem_encoding)
         self.src_library_path = os.path.abspath(library_path)
@@ -107,7 +107,7 @@ class Restore(Thread):
             try:
                 tdir = TemporaryDirectory('_rlib', dir=basedir)
                 tdir.__enter__()
-            except EnvironmentError:
+            except OSError:
                 # In case we dont have permissions to create directories in the
                 # parent folder of the src library
                 tdir = TemporaryDirectory('_rlib')
@@ -279,7 +279,7 @@ class Restore(Thread):
         if os.path.exists(dbpath):
             try:
                 os.rename(dbpath, save_path)
-            except EnvironmentError:
+            except OSError:
                 time.sleep(30)  # Wait a little for dropbox or the antivirus or whatever to release the file
                 shutil.copyfile(dbpath, save_path)
                 os.remove(dbpath)

src/calibre/db/schema_upgrades.py

@@ -10,7 +10,7 @@ import os
 
 from calibre import prints
 from calibre.utils.date import isoformat, DEFAULT_DATE
-from polyglot.builtins import itervalues, unicode_type
+from polyglot.builtins import itervalues
 
 
 class SchemaUpgrade:
@@ -598,10 +598,10 @@ class SchemaUpgrade:
                 existing = frozenset(map(int, custom_recipes))
                 if id_ in existing:
                     id_ = max(existing) + 1000
-                id_ = unicode_type(id_)
+                id_ = str(id_)
                 fname = custom_recipe_filename(id_, title)
                 custom_recipes[id_] = (title, fname)
-                if isinstance(script, unicode_type):
+                if isinstance(script, str):
                     script = script.encode('utf-8')
                 with open(os.path.join(bdir, fname), 'wb') as f:
                     f.write(script)

src/calibre/db/search.py

@@ -18,7 +18,7 @@ from calibre.utils.date import parse_date, UNDEFINED_DATE, now, dt_as_local
 from calibre.utils.icu import primary_contains, sort_key
 from calibre.utils.localization import lang_map, canonicalize_lang
 from calibre.utils.search_query_parser import SearchQueryParser, ParseException
-from polyglot.builtins import iteritems, unicode_type, string_or_bytes
+from polyglot.builtins import iteritems, string_or_bytes
 
 CONTAINS_MATCH = 0
 EQUALS_MATCH   = 1
@@ -149,7 +149,7 @@ class DateSearch:  # {{{
 
         if query == 'false':
             for v, book_ids in field_iter():
-                if isinstance(v, (bytes, unicode_type)):
+                if isinstance(v, (bytes, str)):
                     if isinstance(v, bytes):
                         v = v.decode(preferred_encoding, 'replace')
                     v = parse_date(v)
@@ -159,7 +159,7 @@ class DateSearch:  # {{{
 
         if query == 'true':
             for v, book_ids in field_iter():
-                if isinstance(v, (bytes, unicode_type)):
+                if isinstance(v, (bytes, str)):
                     if isinstance(v, bytes):
                         v = v.decode(preferred_encoding, 'replace')
                     v = parse_date(v)
@@ -413,7 +413,7 @@ class SavedSearchQueries:  # {{{
         return self._db()
 
     def force_unicode(self, x):
-        if not isinstance(x, unicode_type):
+        if not isinstance(x, str):
             x = x.decode(preferred_encoding, 'replace')
         return x
 

src/calibre/db/tables.py

@@ -12,7 +12,7 @@ from collections import defaultdict
 
 from calibre.utils.date import parse_date, UNDEFINED_DATE, utc_tz
 from calibre.ebooks.metadata import author_to_author_sort
-from polyglot.builtins import iteritems, itervalues, range
+from polyglot.builtins import iteritems, itervalues
 from calibre_extensions.speedup import parse_date as _c_speedup
 
 
@@ -103,7 +103,7 @@ class OneToOneTable(Table):
 
     def read(self, db):
         idcol = 'id' if self.metadata['table'] == 'books' else 'book'
-        query = db.execute('SELECT {0}, {1} FROM {2}'.format(idcol,
+        query = db.execute('SELECT {}, {} FROM {}'.format(idcol,
             self.metadata['column'], self.metadata['table']))
         if self.unserialize is None:
             try:
@@ -111,7 +111,7 @@ class OneToOneTable(Table):
             except UnicodeDecodeError:
                 # The db is damaged, try to work around it by ignoring
                 # failures to decode utf-8
-                query = db.execute('SELECT {0}, cast({1} as blob) FROM {2}'.format(idcol,
+                query = db.execute('SELECT {}, cast({} as blob) FROM {}'.format(idcol,
                     self.metadata['column'], self.metadata['table']))
                 self.book_col_map = {k:bytes(val).decode('utf-8', 'replace') for k, val in query}
         else:
@@ -205,7 +205,7 @@ class ManyToOneTable(Table):
         self.read_maps(db)
 
     def read_id_maps(self, db):
-        query = db.execute('SELECT id, {0} FROM {1}'.format(
+        query = db.execute('SELECT id, {} FROM {}'.format(
             self.metadata['column'], self.metadata['table']))
         if self.unserialize is None:
             self.id_map = dict(query)
@@ -217,7 +217,7 @@ class ManyToOneTable(Table):
         cbm = self.col_book_map
         bcm = self.book_col_map
         for book, item_id in db.execute(
-                'SELECT book, {0} FROM {1}'.format(
+                'SELECT book, {} FROM {}'.format(
                     self.metadata['link_column'], self.link_table)):
             cbm[item_id].add(book)
             bcm[book] = item_id
@@ -230,7 +230,7 @@ class ManyToOneTable(Table):
                 book_ids = self.col_book_map.pop(item_id, ())
                 for book_id in book_ids:
                     self.book_col_map.pop(book_id, None)
-            db.executemany('DELETE FROM {0} WHERE {1}=?'.format(
+            db.executemany('DELETE FROM {} WHERE {}=?'.format(
                 self.link_table, self.metadata['link_column']), tuple((x,) for x in extra_item_ids))
 
     def fix_case_duplicates(self, db):
@@ -250,7 +250,7 @@ class ManyToOneTable(Table):
                 db.executemany('UPDATE {0} SET {1}=? WHERE {1}=?'.format(
                     self.link_table, self.metadata['link_column']),
                     tuple((main_id, x) for x in v))
-                db.executemany('DELETE FROM {0} WHERE id=?'.format(self.metadata['table']),
+                db.executemany('DELETE FROM {} WHERE id=?'.format(self.metadata['table']),
                     tuple((x,) for x in v))
 
     def remove_books(self, book_ids, db):
@@ -270,7 +270,7 @@ class ManyToOneTable(Table):
                             clean.add(item_id)
         if clean:
             db.executemany(
-                'DELETE FROM {0} WHERE id=?'.format(self.metadata['table']),
+                'DELETE FROM {} WHERE id=?'.format(self.metadata['table']),
                 [(x,) for x in clean])
         return clean
 
@@ -296,7 +296,7 @@ class ManyToOneTable(Table):
                         # this is a many-to-one mapping we know that we can delete
                         # links without checking the item ID
                         db.executemany(
-                            'DELETE FROM {0} WHERE book=?'.format(self.link_table), tuple((x,) for x in books_to_delete))
+                            'DELETE FROM {} WHERE book=?'.format(self.link_table), tuple((x,) for x in books_to_delete))
                         affected_books |= books_to_delete
                 else:
                     # Process normally any items where the VL was not significant
@@ -314,8 +314,8 @@ class ManyToOneTable(Table):
                 self.book_col_map.pop(book_id, None)
             affected_books.update(book_ids)
         item_ids = tuple((x,) for x in item_ids)
-        db.executemany('DELETE FROM {0} WHERE {1}=?'.format(self.link_table, self.metadata['link_column']), item_ids)
+        db.executemany('DELETE FROM {} WHERE {}=?'.format(self.link_table, self.metadata['link_column']), item_ids)
-        db.executemany('DELETE FROM {0} WHERE id=?'.format(self.metadata['table']), item_ids)
+        db.executemany('DELETE FROM {} WHERE id=?'.format(self.metadata['table']), item_ids)
         return affected_books
 
     def rename_item(self, item_id, new_name, db):
@@ -327,7 +327,7 @@ class ManyToOneTable(Table):
         if existing_item is None or existing_item == item_id:
             # A simple rename will do the trick
             self.id_map[item_id] = new_name
-            db.execute('UPDATE {0} SET {1}=? WHERE id=?'.format(table, col), (new_name, item_id))
+            db.execute('UPDATE {} SET {}=? WHERE id=?'.format(table, col), (new_name, item_id))
         else:
             # We have to replace
             new_id = existing_item
@@ -353,9 +353,9 @@ class RatingTable(ManyToOneTable):
         bad_ids = {item_id for item_id, rating in iteritems(self.id_map) if rating == 0}
         if bad_ids:
             self.id_map = {item_id:rating for item_id, rating in iteritems(self.id_map) if rating != 0}
-            db.executemany('DELETE FROM {0} WHERE {1}=?'.format(self.link_table, self.metadata['link_column']),
+            db.executemany('DELETE FROM {} WHERE {}=?'.format(self.link_table, self.metadata['link_column']),
                                 tuple((x,) for x in bad_ids))
-            db.execute('DELETE FROM {0} WHERE {1}=0'.format(
+            db.execute('DELETE FROM {} WHERE {}=0'.format(
                 self.metadata['table'], self.metadata['column']))
 
 
@@ -389,7 +389,7 @@ class ManyToManyTable(ManyToOneTable):
                 book_ids = self.col_book_map.pop(item_id, ())
                 for book_id in book_ids:
                     self.book_col_map[book_id] = tuple(iid for iid in self.book_col_map.pop(book_id, ()) if iid not in extra_item_ids)
-            db.executemany('DELETE FROM {0} WHERE {1}=?'.format(
+            db.executemany('DELETE FROM {} WHERE {}=?'.format(
                 self.link_table, self.metadata['link_column']), tuple((x,) for x in extra_item_ids))
 
     def remove_books(self, book_ids, db):
@@ -409,7 +409,7 @@ class ManyToManyTable(ManyToOneTable):
                             clean.add(item_id)
         if clean and self.do_clean_on_remove:
             db.executemany(
-                'DELETE FROM {0} WHERE id=?'.format(self.metadata['table']),
+                'DELETE FROM {} WHERE id=?'.format(self.metadata['table']),
                 [(x,) for x in clean])
         return clean
 
@@ -436,7 +436,7 @@ class ManyToManyTable(ManyToOneTable):
             # Delete book/item pairs from the link table. We don't need to do
             # anything with the main table because books with the old ID are
             # still in the library.
-            db.executemany('DELETE FROM {0} WHERE {1}=? and {2}=?'.format(
+            db.executemany('DELETE FROM {} WHERE {}=? and {}=?'.format(
                     self.link_table, 'book', self.metadata['link_column']),
                            [(b, i) for b in affected_books for i in item_ids])
             # Take care of any items where the VL was not significant
@@ -453,8 +453,8 @@ class ManyToManyTable(ManyToOneTable):
                 self.book_col_map[book_id] = tuple(x for x in self.book_col_map.get(book_id, ()) if x != item_id)
             affected_books.update(book_ids)
         item_ids = tuple((x,) for x in item_ids)
-        db.executemany('DELETE FROM {0} WHERE {1}=?'.format(self.link_table, self.metadata['link_column']), item_ids)
+        db.executemany('DELETE FROM {} WHERE {}=?'.format(self.link_table, self.metadata['link_column']), item_ids)
-        db.executemany('DELETE FROM {0} WHERE id=?'.format(self.metadata['table']), item_ids)
+        db.executemany('DELETE FROM {} WHERE id=?'.format(self.metadata['table']), item_ids)
         return affected_books
 
     def rename_item(self, item_id, new_name, db):
@@ -466,7 +466,7 @@ class ManyToManyTable(ManyToOneTable):
         if existing_item is None or existing_item == item_id:
             # A simple rename will do the trick
             self.id_map[item_id] = new_name
-            db.execute('UPDATE {0} SET {1}=? WHERE id=?'.format(table, col), (new_name, item_id))
+            db.execute('UPDATE {} SET {}=? WHERE id=?'.format(table, col), (new_name, item_id))
         else:
             # We have to replace
             new_id = existing_item
@@ -478,7 +478,7 @@ class ManyToManyTable(ManyToOneTable):
             for book_id in books:
                 self.book_col_map[book_id] = tuple((existing_item if x == item_id else x) for x in self.book_col_map.get(book_id, ()) if x != existing_item)
             self.col_book_map[existing_item].update(books)
-            db.executemany('DELETE FROM {0} WHERE book=? AND {1}=?'.format(self.link_table, lcol), [
+            db.executemany('DELETE FROM {} WHERE book=? AND {}=?'.format(self.link_table, lcol), [
                 (book_id, existing_item) for book_id in books])
             db.execute('UPDATE {0} SET {1}=? WHERE {1}=?; DELETE FROM {2} WHERE id=?'.format(
                 self.link_table, lcol, table), (existing_item, item_id, item_id))
@@ -515,11 +515,11 @@ class ManyToManyTable(ManyToOneTable):
                                 tuple((main_id, x, book_id) for x in v))
                         else:
                             # duplicates
-                            db.execute('DELETE FROM {0} WHERE book=?'.format(self.link_table), (book_id,))
+                            db.execute('DELETE FROM {} WHERE book=?'.format(self.link_table), (book_id,))
                             db.executemany(
-                                'INSERT INTO {0} (book,{1}) VALUES (?,?)'.format(self.link_table, self.metadata['link_column']),
+                                'INSERT INTO {} (book,{}) VALUES (?,?)'.format(self.link_table, self.metadata['link_column']),
                                 tuple((book_id, x) for x in vals))
-                db.executemany('DELETE FROM {0} WHERE id=?'.format(self.metadata['table']),
+                db.executemany('DELETE FROM {} WHERE id=?'.format(self.metadata['table']),
                     tuple((x,) for x in v))
 
 

src/calibre/db/tests/base.py

@@ -9,7 +9,6 @@ __docformat__ = 'restructuredtext en'
 import unittest, os, shutil, tempfile, atexit, gc, time
 from functools import partial
 from io import BytesIO
-from polyglot.builtins import map, unicode_type
 
 rmtree = partial(shutil.rmtree, ignore_errors=True)
 
@@ -33,7 +32,7 @@ class BaseTest(unittest.TestCase):
         gc.collect(), gc.collect()
         try:
             shutil.rmtree(self.library_path)
-        except EnvironmentError:
+        except OSError:
             # Try again in case something transient has a file lock on windows
             gc.collect(), gc.collect()
             time.sleep(2)
@@ -82,7 +81,7 @@ class BaseTest(unittest.TestCase):
             atexit.register(rmtree, self.clone_dir)
             self.clone_count = 0
         self.clone_count += 1
-        dest = os.path.join(self.clone_dir, unicode_type(self.clone_count))
+        dest = os.path.join(self.clone_dir, str(self.clone_count))
         shutil.copytree(library_path, dest)
         return dest
 

src/calibre/db/tests/legacy.py

@@ -12,7 +12,7 @@ from operator import itemgetter
 
 from calibre.library.field_metadata import fm_as_dict
 from calibre.db.tests.base import BaseTest
-from polyglot.builtins import iteritems, range, unicode_type, zip
+from polyglot.builtins import iteritems
 from polyglot import reprlib
 
 # Utils {{{
@@ -62,7 +62,7 @@ def run_funcs(self, db, ndb, funcs):
             if meth[0] in {'!', '@', '#', '+', '$', '-', '%'}:
                 if meth[0] != '+':
                     fmt = {'!':dict, '@':lambda x:frozenset(x or ()), '#':lambda x:set((x or '').split(',')),
-                           '$':lambda x:set(tuple(y) for y in x), '-':lambda x:None,
+                           '$':lambda x:{tuple(y) for y in x}, '-':lambda x:None,
                            '%':lambda x: set((x or '').split(','))}[meth[0]]
                 else:
                     fmt = args[-1]
@@ -116,7 +116,7 @@ class LegacyTest(BaseTest):
             for label, loc in iteritems(db.FIELD_MAP):
                 if isinstance(label, numbers.Integral):
                     label = '#'+db.custom_column_num_map[label]['label']
-                label = unicode_type(label)
+                label = str(label)
                 ans[label] = tuple(db.get_property(i, index_is_id=True, loc=loc)
                                    for i in db.all_ids())
                 if label in ('id', 'title', '#tags'):
@@ -282,7 +282,7 @@ class LegacyTest(BaseTest):
         old = db.get_data_as_dict(prefix='test-prefix')
         new = ndb.get_data_as_dict(prefix='test-prefix')
         for o, n in zip(old, new):
-            o = {unicode_type(k) if isinstance(k, bytes) else k:set(v) if isinstance(v, list) else v for k, v in iteritems(o)}
+            o = {str(k) if isinstance(k, bytes) else k:set(v) if isinstance(v, list) else v for k, v in iteritems(o)}
             n = {k:set(v) if isinstance(v, list) else v for k, v in iteritems(n)}
             self.assertEqual(o, n)
 
@@ -516,7 +516,7 @@ class LegacyTest(BaseTest):
             T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
             T((name, object()))
             T = partial(ET, 'delete_all_custom_book_data', old=old, legacy=legacy)
-            T((name))
+            T(name)
             T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
             T((name, object()))
 

src/calibre/db/tests/locking.py

@@ -9,7 +9,6 @@ import time, random
 from threading import Thread
 from calibre.db.tests.base import BaseTest
 from calibre.db.locking import SHLock, RWLockWrapper, LockingError
-from polyglot.builtins import range
 
 
 def wait_for(period):

src/calibre/db/tests/reading.py

@@ -13,7 +13,7 @@ from time import time
 from calibre.utils.date import utc_tz
 from calibre.utils.localization import calibre_langcode_to_name
 from calibre.db.tests.base import BaseTest
-from polyglot.builtins import iteritems, itervalues, range
+from polyglot.builtins import iteritems, itervalues
 
 
 def p(x):

src/calibre/db/tests/writing.py

@@ -15,7 +15,7 @@ from calibre.ebooks.metadata.book.base import Metadata
 from calibre.utils.date import UNDEFINED_DATE
 from calibre.db.tests.base import BaseTest, IMG
 from calibre.db.backend import FTSQueryError
-from polyglot.builtins import iteritems, itervalues, unicode_type
+from polyglot.builtins import iteritems, itervalues
 
 
 class WritingTest(BaseTest):
@@ -664,11 +664,11 @@ class WritingTest(BaseTest):
     def test_set_author_data(self):  # {{{
         cache = self.init_cache()
         adata = cache.author_data()
-        ldata = {aid:unicode_type(aid) for aid in adata}
+        ldata = {aid:str(aid) for aid in adata}
         self.assertEqual({1,2,3}, cache.set_link_for_authors(ldata))
         for c in (cache, self.init_cache()):
             self.assertEqual(ldata, {aid:d['link'] for aid, d in iteritems(c.author_data())})
-        self.assertEqual({3}, cache.set_link_for_authors({aid:'xxx' if aid == max(adata) else unicode_type(aid) for aid in adata}),
+        self.assertEqual({3}, cache.set_link_for_authors({aid:'xxx' if aid == max(adata) else str(aid) for aid in adata}),
                          'Setting the author link to the same value as before, incorrectly marked some books as dirty')
         sdata = {aid:'%s, changed' % aid for aid in adata}
         self.assertEqual({1,2,3}, cache.set_sort_for_authors(sdata))

src/calibre/db/utils.py

@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 import os, errno, sys, re
 from locale import localeconv
 from collections import OrderedDict, namedtuple
-from polyglot.builtins import iteritems, itervalues, map, unicode_type, string_or_bytes, filter
+from polyglot.builtins import iteritems, itervalues, string_or_bytes
 from threading import Lock
 
 from calibre import as_unicode, prints
@@ -18,7 +18,7 @@ from calibre.utils.localization import canonicalize_lang
 
 
 def force_to_bool(val):
-    if isinstance(val, (bytes, unicode_type)):
+    if isinstance(val, (bytes, str)):
         if isinstance(val, bytes):
             val = val.decode(preferred_encoding, 'replace')
         try:
@@ -136,7 +136,7 @@ class ThumbnailCache:
     def _do_delete(self, path):
         try:
             os.remove(path)
-        except EnvironmentError as err:
+        except OSError as err:
             self.log('Failed to delete cached thumbnail file:', as_unicode(err))
 
     def _load_index(self):
@@ -153,7 +153,7 @@ class ThumbnailCache:
         def listdir(*args):
             try:
                 return os.listdir(os.path.join(*args))
-            except EnvironmentError:
+            except OSError:
                 return ()  # not a directory or no permission or whatever
         entries = ('/'.join((parent, subdir, entry))
                    for parent in listdir(self.location)
@@ -164,13 +164,13 @@ class ThumbnailCache:
         try:
             with open(os.path.join(self.location, 'invalidate'), 'rb') as f:
                 raw = f.read().decode('utf-8')
-        except EnvironmentError as err:
+        except OSError as err:
             if getattr(err, 'errno', None) != errno.ENOENT:
                 self.log('Failed to read thumbnail invalidate data:', as_unicode(err))
         else:
             try:
                 os.remove(os.path.join(self.location, 'invalidate'))
-            except EnvironmentError as err:
+            except OSError as err:
                 self.log('Failed to remove thumbnail invalidate data:', as_unicode(err))
             else:
                 def record(line):
@@ -198,7 +198,7 @@ class ThumbnailCache:
                     self.total_size += size
                 else:
                     self._do_delete(path)
-        except EnvironmentError as err:
+        except OSError as err:
             self.log('Failed to read thumbnail cache dir:', as_unicode(err))
 
         self.items = OrderedDict(sorted(items, key=lambda x:order.get(x[0], 0)))
@@ -227,10 +227,10 @@ class ThumbnailCache:
     def _write_order(self):
         if hasattr(self, 'items'):
             try:
-                data = '\n'.join(group_id + ' ' + unicode_type(book_id) for (group_id, book_id) in self.items)
+                data = '\n'.join(group_id + ' ' + str(book_id) for (group_id, book_id) in self.items)
                 with lopen(os.path.join(self.location, 'order'), 'wb') as f:
                     f.write(data.encode('utf-8'))
-            except EnvironmentError as err:
+            except OSError as err:
                 self.log('Failed to save thumbnail cache order:', as_unicode(err))
 
     def _read_order(self):
@@ -281,14 +281,14 @@ class ThumbnailCache:
             try:
                 with open(path, 'wb') as f:
                     f.write(data)
-            except EnvironmentError as err:
+            except OSError as err:
                 d = os.path.dirname(path)
                 if not os.path.exists(d):
                     try:
                         os.makedirs(d)
                         with open(path, 'wb') as f:
                             f.write(data)
-                    except EnvironmentError as err:
+                    except OSError as err:
                         self.log('Failed to write cached thumbnail:', path, as_unicode(err))
                         return self._apply_size()
                 else:
@@ -326,7 +326,7 @@ class ThumbnailCache:
             if entry.thumbnail_size != self.thumbnail_size:
                 try:
                     os.remove(entry.path)
-                except EnvironmentError as err:
+                except OSError as err:
                     if getattr(err, 'errno', None) != errno.ENOENT:
                         self.log('Failed to remove cached thumbnail:', entry.path, as_unicode(err))
                 self.total_size -= entry.size
@@ -335,7 +335,7 @@ class ThumbnailCache:
             try:
                 with open(entry.path, 'rb') as f:
                     data = f.read()
-            except EnvironmentError as err:
+            except OSError as err:
                 self.log('Failed to read cached thumbnail:', entry.path, as_unicode(err))
                 return None, None
             return data, entry.timestamp
@@ -350,7 +350,7 @@ class ThumbnailCache:
                     raw = '\n'.join('%s %d' % (self.group_id, book_id) for book_id in book_ids)
                     with open(os.path.join(self.location, 'invalidate'), 'ab') as f:
                         f.write(raw.encode('ascii'))
-                except EnvironmentError as err:
+                except OSError as err:
                     self.log('Failed to write invalidate thumbnail record:', as_unicode(err))
 
     @property
@@ -364,7 +364,7 @@ class ThumbnailCache:
         with self.lock:
             try:
                 os.remove(os.path.join(self.location, 'order'))
-            except EnvironmentError:
+            except OSError:
                 pass
             if not hasattr(self, 'total_size'):
                 self._load_index()

src/calibre/db/view.py

@@ -8,8 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import weakref, operator, numbers
 from functools import partial
-from polyglot.builtins import (iteritems, itervalues, map,
+from polyglot.builtins import iteritems, itervalues
-        unicode_type, range)
 
 from calibre.ebooks.metadata import title_sort
 from calibre.utils.config_base import tweaks, prefs
@@ -175,8 +174,7 @@ class View:
             yield TableRow(book_id, self)
 
     def iterallids(self):
-        for book_id in sorted(self._map):
+        yield from sorted(self._map)
-            yield book_id
 
     def tablerow_for_id(self, book_id):
         return TableRow(book_id, self)
@@ -281,7 +279,7 @@ class View:
     def _build_restriction_string(self, restriction):
         if self.base_restriction:
             if restriction:
-                return u'(%s) and (%s)' % (self.base_restriction, restriction)
+                return '(%s) and (%s)' % (self.base_restriction, restriction)
             else:
                 return self.base_restriction
         else:
@@ -297,7 +295,7 @@ class View:
         else:
             q = query
             if search_restriction:
-                q = u'(%s) and (%s)' % (search_restriction, query)
+                q = '(%s) and (%s)' % (search_restriction, query)
         if not q:
             if set_restriction_count:
                 self.search_restriction_book_count = len(self._map)
@@ -374,10 +372,10 @@ class View:
         old_marked_ids = set(self.marked_ids)
         if not hasattr(id_dict, 'items'):
             # Simple list. Make it a dict of string 'true'
-            self.marked_ids = dict.fromkeys(id_dict, u'true')
+            self.marked_ids = dict.fromkeys(id_dict, 'true')
         else:
             # Ensure that all the items in the dict are text
-            self.marked_ids = {k: unicode_type(v) for k, v in iteritems(id_dict)}
+            self.marked_ids = {k: str(v) for k, v in iteritems(id_dict)}
         # This invalidates all searches in the cache even though the cache may
         # be shared by multiple views. This is not ideal, but...
         cmids = set(self.marked_ids)

src/calibre/db/write.py

@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import re
 from functools import partial
 from datetime import datetime
-from polyglot.builtins import iteritems, itervalues, unicode_type, zip
+from polyglot.builtins import iteritems, itervalues
 
 from calibre.constants import preferred_encoding
 from calibre.ebooks.metadata import author_to_author_sort, title_sort
@@ -30,7 +30,7 @@ def sqlite_datetime(x):
 def single_text(x):
     if x is None:
         return x
-    if not isinstance(x, unicode_type):
+    if not isinstance(x, str):
         x = x.decode(preferred_encoding, 'replace')
     x = x.strip()
     return x if x else None
@@ -58,7 +58,7 @@ def multiple_text(sep, ui_sep, x):
         return ()
     if isinstance(x, bytes):
         x = x.decode(preferred_encoding, 'replace')
-    if isinstance(x, unicode_type):
+    if isinstance(x, str):
         x = x.split(sep)
     else:
         x = (y.decode(preferred_encoding, 'replace') if isinstance(y, bytes)
@@ -70,7 +70,7 @@ def multiple_text(sep, ui_sep, x):
 
 
 def adapt_datetime(x):
-    if isinstance(x, (unicode_type, bytes)):
+    if isinstance(x, (str, bytes)):
         x = parse_date(x, assume_utc=False, as_utc=False)
     if x and is_date_undefined(x):
         x = UNDEFINED_DATE
@@ -78,7 +78,7 @@ def adapt_datetime(x):
 
 
 def adapt_date(x):
-    if isinstance(x, (unicode_type, bytes)):
+    if isinstance(x, (str, bytes)):
         x = parse_only_date(x)
     if x is None or is_date_undefined(x):
         x = UNDEFINED_DATE
@@ -88,7 +88,7 @@ def adapt_date(x):
 def adapt_number(typ, x):
     if x is None:
         return None
-    if isinstance(x, (unicode_type, bytes)):
+    if isinstance(x, (str, bytes)):
         if isinstance(x, bytes):
             x = x.decode(preferred_encoding, 'replace')
         if not x or x.lower() == 'none':
@@ -97,7 +97,7 @@ def adapt_number(typ, x):
 
 
 def adapt_bool(x):
-    if isinstance(x, (unicode_type, bytes)):
+    if isinstance(x, (str, bytes)):
         if isinstance(x, bytes):
             x = x.decode(preferred_encoding, 'replace')
         x = x.lower()
@@ -471,7 +471,7 @@ def many_many(book_id_val_map, db, field, allow_case_change, *args):
         )
         db.executemany('DELETE FROM %s WHERE book=?'%table.link_table,
                             ((k,) for k in updated))
-        db.executemany('INSERT INTO {0}(book,{1}) VALUES(?, ?)'.format(
+        db.executemany('INSERT INTO {}(book,{}) VALUES(?, ?)'.format(
             table.link_table, m['link_column']), vals)
         if is_authors:
             aus_map = {book_id:field.author_sort_for_book(book_id) for book_id

src/calibre/debug.py

@@ -12,7 +12,7 @@ from calibre.utils.config import OptionParser
 from calibre.constants import iswindows
 from calibre import prints
 from calibre.startup import get_debug_executable
-from polyglot.builtins import exec_path, raw_input, unicode_type, getcwd
+from polyglot.builtins import exec_path
 
 
 def run_calibre_debug(*args, **kw):
@@ -156,7 +156,7 @@ def debug_device_driver():
     from calibre.devices import debug
     debug(ioreg_to_tmp=True, buf=sys.stdout)
     if iswindows:  # no2to3
-        raw_input('Press Enter to continue...')  # no2to3
+        input('Press Enter to continue...')  # no2to3
 
 
 def add_simple_plugin(path_to_plugin):
@@ -164,7 +164,7 @@ def add_simple_plugin(path_to_plugin):
     tdir = tempfile.mkdtemp()
     open(os.path.join(tdir, 'custom_plugin.py'),
             'wb').write(open(path_to_plugin, 'rb').read())
-    odir = getcwd()
+    odir = os.getcwd()
     os.chdir(tdir)
     zf = zipfile.ZipFile('plugin.zip', 'w')
     zf.write('custom_plugin.py')
@@ -204,11 +204,11 @@ def print_basic_debug_info(out=None):
             out('Linux:', platform.linux_distribution())
     except:
         pass
-    out('Interface language:', unicode_type(set_translators.lang))
+    out('Interface language:', str(set_translators.lang))
     from calibre.customize.ui import has_external_plugins, initialized_plugins
     if has_external_plugins():
         from calibre.customize import PluginInstallationType
-        names = ('{0} {1}'.format(p.name, p.version) for p in initialized_plugins()
+        names = ('{} {}'.format(p.name, p.version) for p in initialized_plugins()
                  if getattr(p, 'installation_type', None) is not PluginInstallationType.BUILTIN)
         out('Successfully initialized third party plugins:', ' && '.join(names))
 

src/calibre/devices/__init__.py

@@ -1,4 +1,3 @@
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
@@ -8,7 +7,6 @@ Device drivers.
 
 import sys, time, pprint
 from functools import partial
-from polyglot.builtins import zip, unicode_type
 
 DAY_MAP   = dict(Sun=0, Mon=1, Tue=2, Wed=3, Thu=4, Fri=5, Sat=6)
 MONTH_MAP = dict(Jan=1, Feb=2, Mar=3, Apr=4, May=5, Jun=6, Jul=7, Aug=8, Sep=9, Oct=10, Nov=11, Dec=12)
@@ -19,8 +17,8 @@ INVERSE_MONTH_MAP = dict(zip(MONTH_MAP.values(), MONTH_MAP.keys()))
 def strptime(src):
     src = src.strip()
     src = src.split()
-    src[0] = unicode_type(DAY_MAP[src[0][:-1]])+','
+    src[0] = str(DAY_MAP[src[0][:-1]])+','
-    src[2] = unicode_type(MONTH_MAP[src[2]])
+    src[2] = str(MONTH_MAP[src[2]])
     return time.strptime(' '.join(src), '%w, %d %m %Y %H:%M:%S %Z')
 
 

src/calibre/devices/blackberry/__init__.py

@@ -1,5 +1,3 @@
-
-
 __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'

src/calibre/devices/boeye/driver.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2011,  Ken <ken at szboeye.com>'
 __docformat__ = 'restructuredtext en'

src/calibre/devices/cli.py

@@ -17,7 +17,6 @@ from calibre.devices.errors import ArgumentError, DeviceError, DeviceLocked
 from calibre.customize.ui import device_plugins
 from calibre.devices.scanner import DeviceScanner
 from calibre.utils.config import device_prefs
-from polyglot.builtins import unicode_type
 from polyglot.io import PolyglotStringIO
 
 MINIMUM_COL_WIDTH = 12  # : Minimum width of columns in ls output
@@ -125,7 +124,7 @@ def ls(dev, path, recurse=False, human_readable_size=False, ll=False, cols=0):
         maxlen = 0
         if ll:  # Calculate column width for size column
             for file in files:
-                size = len(unicode_type(file.size))
+                size = len(str(file.size))
                 if human_readable_size:
                     file = FileFormatter(file)
                     size = len(file.human_readable_size)
@@ -137,10 +136,10 @@ def ls(dev, path, recurse=False, human_readable_size=False, ll=False, cols=0):
             lsoutput.append(name)
             lscoloutput.append(name)
             if ll:
-                size = unicode_type(file.size)
+                size = str(file.size)
                 if human_readable_size:
                     size = file.human_readable_size
-                prints(file.mode_string, ("%"+unicode_type(maxlen)+"s")%size, file.modification_time, name, file=output)
+                prints(file.mode_string, ("%"+str(maxlen)+"s")%size, file.modification_time, name, file=output)
         if not ll and len(lsoutput) > 0:
             trytable = []
             for colwidth in range(MINIMUM_COL_WIDTH, cols):
@@ -244,7 +243,7 @@ def main():
             print("Filesystem\tSize \tUsed \tAvail \tUse%")
             for i in range(3):
                 print("%-10s\t%s\t%s\t%s\t%s"%(where[i], human_readable(total[i]), human_readable(total[i]-free[i]), human_readable(free[i]),
-                                                                            unicode_type(0 if total[i]==0 else int(100*(total[i]-free[i])/(total[i]*1.)))+"%"))
+                                                                            str(0 if total[i]==0 else int(100*(total[i]-free[i])/(total[i]*1.)))+"%"))
         elif command == 'eject':
             dev.eject()
         elif command == "books":
@@ -302,7 +301,7 @@ def main():
                     outfile = os.path.join(outfile, path[path.rfind("/")+1:])
                 try:
                     outfile = lopen(outfile, "wb")
-                except IOError as e:
+                except OSError as e:
                     print(e, file=sys.stderr)
                     parser.print_help()
                     return 1
@@ -312,7 +311,7 @@ def main():
             elif args[1].startswith("dev:"):
                 try:
                     infile = lopen(args[0], "rb")
-                except IOError as e:
+                except OSError as e:
                     print(e, file=sys.stderr)
                     parser.print_help()
                     return 1

src/calibre/devices/eb600/__init__.py

@@ -1 +0,0 @@
-

src/calibre/devices/errors.py

@@ -1,5 +1,3 @@
-
-
 __license__ = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 """
@@ -8,7 +6,6 @@ Defines the errors that the device drivers generate.
 G{classtree ProtocolError}
 """
 
-from polyglot.builtins import unicode_type
 
 
 class ProtocolError(Exception):
@@ -95,7 +92,7 @@ class DeviceBusy(ProtocolError):
     def __init__(self, uerr=""):
         ProtocolError.__init__(
             self, "Device is in use by another application:"
-            "\nUnderlying error:" + unicode_type(uerr)
+            "\nUnderlying error:" + str(uerr)
         )
 
 
@@ -138,9 +135,9 @@ class ControlError(ProtocolError):
     def __str__(self):
         if self.query and self.response:
             return "Got unexpected response:\n" + \
-           "query:\n"+unicode_type(self.query.query)+"\n"+\
+           "query:\n"+str(self.query.query)+"\n"+\
-           "expected:\n"+unicode_type(self.query.response)+"\n" +\
+           "expected:\n"+str(self.query.response)+"\n" +\
-           "actual:\n"+unicode_type(self.response)
+           "actual:\n"+str(self.response)
         if self.desc:
             return self.desc
         return "Unknown control error occurred"

src/calibre/devices/folder_device/driver.py

@@ -1,5 +1,3 @@
-
-
 '''
 Created on 15 May 2010
 
@@ -63,7 +61,7 @@ class FOLDER_DEVICE(USBMS):
 
     def __init__(self, path):
         if not os.path.isdir(path):
-            raise IOError('Path is not a folder')
+            raise OSError('Path is not a folder')
         path = USBMS.normalize_path(path)
         if path.endswith(os.sep):
             self._main_prefix = path

src/calibre/devices/hanlin/__init__.py

@@ -1,4 +1,2 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2009, Tijmen Ruizendaal <tijmen at mybebook.com>'

src/calibre/devices/interface.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import os

src/calibre/devices/jetbook/driver.py

@@ -15,7 +15,6 @@ import re
 from calibre.constants import filesystem_encoding
 from calibre.devices.usbms.driver import USBMS
 from calibre.ebooks.metadata import string_to_authors
-from polyglot.builtins import unicode_type, map
 
 
 class JETBOOK(USBMS):
@@ -65,7 +64,7 @@ class JETBOOK(USBMS):
     def metadata_from_path(cls, path):
 
         def check_unicode(txt):
-            if not isinstance(txt, unicode_type):
+            if not isinstance(txt, str):
                 txt = txt.decode(filesystem_encoding, 'replace')
             txt = txt.replace('_', ' ')
             return txt

src/calibre/devices/kindle/__init__.py

@@ -1 +0,0 @@
-

src/calibre/devices/kindle/apnx.py

@@ -18,7 +18,7 @@ from calibre.ebooks.mobi.reader.headers import MetadataHeader
 from calibre.utils.logging import default_log
 from calibre import prints, fsync
 from calibre.constants import DEBUG
-from polyglot.builtins import range, as_unicode, as_bytes, unicode_type, map
+from polyglot.builtins import as_unicode, as_bytes
 
 
 class APNXBuilder:
@@ -33,7 +33,7 @@ class APNXBuilder:
         using either the fast or accurate algorithm.
         '''
         import uuid
-        apnx_meta = {'guid': unicode_type(uuid.uuid4()).replace('-', '')[:8], 'asin':
+        apnx_meta = {'guid': str(uuid.uuid4()).replace('-', '')[:8], 'asin':
                 '', 'cdetype': 'EBOK', 'format': 'MOBI_7', 'acr': ''}
 
         with lopen(mobi_file_path, 'rb') as mf:
@@ -53,11 +53,11 @@ class APNXBuilder:
             if mh.exth is None or not mh.exth.cdetype:
                 apnx_meta['cdetype'] = 'EBOK'
             else:
-                apnx_meta['cdetype'] = unicode_type(mh.exth.cdetype)
+                apnx_meta['cdetype'] = str(mh.exth.cdetype)
             if mh.exth is None or not mh.exth.uuid:
                 apnx_meta['asin'] = ''
             else:
-                apnx_meta['asin'] = unicode_type(mh.exth.uuid)
+                apnx_meta['asin'] = str(mh.exth.uuid)
 
         # Get the pages depending on the chosen parser
         pages = []

src/calibre/devices/kindle/bookmark.py

@@ -154,7 +154,7 @@ class Bookmark():  # {{{
                 split = my_clippings.find('documents') + len('documents/')
                 my_clippings = my_clippings[:split] + "My Clippings.txt"
                 try:
-                    with io.open(my_clippings, encoding='utf-8', errors='replace') as f2:
+                    with open(my_clippings, encoding='utf-8', errors='replace') as f2:
                         marker_found = 0
                         text = ''
                         search_str1 = '%s' % (mi.title)

src/calibre/devices/kindle/driver.py

@@ -15,7 +15,7 @@ from calibre.constants import DEBUG, filesystem_encoding
 from calibre.devices.kindle.bookmark import Bookmark
 from calibre.devices.usbms.driver import USBMS
 from calibre import strftime, fsync, prints
-from polyglot.builtins import unicode_type, as_bytes, as_unicode
+from polyglot.builtins import as_bytes, as_unicode
 
 '''
 Notes on collections:
@@ -232,7 +232,7 @@ class KINDLE(USBMS):
                     pr=percent_read)
         else:
             markup = _("%(time)s<br />Last page read: Location %(loc)d (%(pr)d%%)") % dict(
-                    time=strftime(u'%x', timestamp.timetuple()),
+                    time=strftime('%x', timestamp.timetuple()),
                     loc=last_read_location,
                     pr=percent_read)
         spanTag = BeautifulSoup('<span style="font-weight:bold">' + markup + '</span>').find('span')
@@ -313,7 +313,7 @@ class KINDLE(USBMS):
                                             bm.value.path, index_is_id=True)
         elif bm.type == 'kindle_clippings':
             # Find 'My Clippings' author=Kindle in database, or add
-            last_update = 'Last modified %s' % strftime(u'%x %X',bm.value['timestamp'].timetuple())
+            last_update = 'Last modified %s' % strftime('%x %X',bm.value['timestamp'].timetuple())
             mc_id = list(db.data.search_getting_ids('title:"My Clippings"', '', sort_results=False))
             if mc_id:
                 db.add_format_with_hooks(mc_id[0], 'TXT', bm.value['path'],
@@ -524,7 +524,7 @@ class KINDLE2(KINDLE):
             cache_dir = self.amazon_cover_bug_cache_dir()
             try:
                 os.mkdir(cache_dir)
-            except EnvironmentError:
+            except OSError:
                 pass
             with lopen(os.path.join(cache_dir, os.path.basename(tp)), 'wb') as f:
                 f.write(coverdata[2])
@@ -545,7 +545,7 @@ class KINDLE2(KINDLE):
             dest_path = os.path.join(dest_dir, name)
             try:
                 dest_stat_result = os.lstat(dest_path)
-            except EnvironmentError:
+            except OSError:
                 needs_sync = True
             else:
                 needs_sync = src_stat_result.st_size != dest_stat_result.st_size
@@ -567,7 +567,7 @@ class KINDLE2(KINDLE):
                 for tp in (tp1, tp2):
                     try:
                         os.remove(tp)
-                    except EnvironmentError as err:
+                    except OSError as err:
                         if err.errno != errno.ENOENT:
                             prints('Failed to delete thumbnail for {!r} at {!r} with error: {}'.format(path, tp, err))
         except Exception:
@@ -610,7 +610,7 @@ class KINDLE2(KINDLE):
                 cust_col_name = opts.extra_customization[self.OPT_APNX_METHOD_COL]
                 if cust_col_name:
                     try:
-                        temp = unicode_type(metadata.get(cust_col_name)).lower()
+                        temp = str(metadata.get(cust_col_name)).lower()
                         if temp in self.EXTRA_CUSTOMIZATION_CHOICES[self.OPT_APNX_METHOD]:
                             method = temp
                         else:

src/calibre/devices/kobo/bookmark.py

@@ -57,7 +57,7 @@ class Bookmark():  # {{{
             'ORDER BY bm.ContentID, bm.chapterprogress'
         )
 
-        debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapters: contentId={0}".format(self.contentId))
+        debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapters: contentId={}".format(self.contentId))
         cursor.execute(kepub_chapter_query, book_query_values)
         kepub_chapters = {}
         if self.kepub:
@@ -69,7 +69,7 @@ class Bookmark():  # {{{
                                                          'chapter_title': chapter_row['Title'],
                                                          'chapter_index': chapter_row['VolumeIndex']
                                                         }
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapter: kepub chapters={0}".format(kepub_chapters))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapter: kepub chapters={}".format(kepub_chapters))
             except:
                 debug_print("Kobo::Bookmark::get_bookmark_data - No chapters found")
 
@@ -83,20 +83,20 @@ class Bookmark():  # {{{
             # For kepubs on newer firmware, the title needs to come from an 899 row.
             if self.kepub:
                 chapter_contentID = row['ContentID']
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter chapter_contentID='{0}'".format(chapter_contentID))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter chapter_contentID='{}'".format(chapter_contentID))
                 filename_index = chapter_contentID.find('!')
                 book_contentID_part = chapter_contentID[:filename_index]
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter book_contentID_part='{0}'".format(book_contentID_part))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter book_contentID_part='{}'".format(book_contentID_part))
                 file_contentID_part = chapter_contentID[filename_index + 1:]
                 filename_index = file_contentID_part.find('!')
                 opf_reference = file_contentID_part[:filename_index]
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter opf_reference='{0}'".format(opf_reference))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter opf_reference='{}'".format(opf_reference))
                 file_contentID_part = file_contentID_part[filename_index + 1:]
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter file_contentID_part='{0}'".format(file_contentID_part))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub: chapter file_contentID_part='{}'".format(file_contentID_part))
 #                 from urllib import quote
 #                 file_contentID_part = quote(file_contentID_part)
                 chapter_contentID = book_contentID_part + "!" + opf_reference + "!" + file_contentID_part
-                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapter chapter_contentID='{0}'".format(chapter_contentID))
+                debug_print("Kobo::Bookmark::get_bookmark_data - getting kepub chapter chapter_contentID='{}'".format(chapter_contentID))
                 kepub_chapter = kepub_chapters.get(chapter_contentID, None)
                 if kepub_chapter is not None:
                     chapter_title = kepub_chapter['chapter_title']

src/calibre/devices/kobo/books.py

@@ -1,4 +1,3 @@
-
 __license__   = 'GPL v3'
 __copyright__ = '2010-2012, , Timothy Legge <timlegge at gmail.com> and David Forrester <davidfor@internode.on.net>'
 __docformat__ = 'restructuredtext en'
@@ -29,7 +28,7 @@ class Book(Book_):
         if show_debug:
             debug_print("Book::__init__ - title=", title, 'authors=', authors)
             debug_print("Book::__init__ - other=", other)
-        super(Book, self).__init__(prefix, lpath, size, other)
+        super().__init__(prefix, lpath, size, other)
 
         if title is not None and len(title) > 0:
             self.title = title
@@ -117,7 +116,7 @@ class Book(Book_):
 
         ans = '\n'.join(ans)
 
-        return super(Book,self).__str__() + "\n" + ans
+        return super().__str__() + "\n" + ans
 
 
 class ImageWrapper:
@@ -129,7 +128,7 @@ class ImageWrapper:
 class KTCollectionsBookList(CollectionsBookList):
 
     def __init__(self, oncard, prefix, settings):
-        super(KTCollectionsBookList, self).__init__(oncard, prefix, settings)
+        super().__init__(oncard, prefix, settings)
         self.set_device_managed_collections([])
 
     def get_collections(self, collection_attributes):

src/calibre/devices/kobo/driver.py

@@ -33,7 +33,7 @@ from calibre import prints, fsync
 from calibre.ptempfile import PersistentTemporaryFile, better_mktemp
 from calibre.constants import DEBUG
 from calibre.utils.config_base import prefs
-from polyglot.builtins import iteritems, itervalues, unicode_type, string_or_bytes
+from polyglot.builtins import iteritems, itervalues, string_or_bytes
 
 EPUB_EXT  = '.epub'
 KEPUB_EXT = '.kepub'
@@ -47,7 +47,7 @@ def qhash(inputstr):
     instr = b""
     if isinstance(inputstr, bytes):
         instr = inputstr
-    elif isinstance(inputstr, unicode_type):
+    elif isinstance(inputstr, str):
         instr = inputstr.encode("utf8")
     else:
         return -1
@@ -203,7 +203,7 @@ class KOBO(USBMS):
         try:
             with lopen(self.normalize_path(self._main_prefix + '.kobo/version'), 'rb') as f:
                 fwversion = f.readline().split(b',')[2]
-                fwversion = tuple((int(x) for x in fwversion.split(b'.')))
+                fwversion = tuple(int(x) for x in fwversion.split(b'.'))
         except Exception:
             debug_print("Kobo::get_firmware_version - didn't get firmware version from file'")
             fwversion = (0,0,0)
@@ -377,7 +377,7 @@ class KOBO(USBMS):
             try:
                 cursor.execute(query)
             except Exception as e:
-                err = unicode_type(e)
+                err = str(e)
                 if not (any_in(err, '___ExpirationStatus', 'FavouritesIndex', 'Accessibility', 'IsDownloaded')):
                     raise
                 query= ('select Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
@@ -483,13 +483,13 @@ class KOBO(USBMS):
                     cursor.execute('update content set ReadStatus=0, FirstTimeReading = \'true\', ___PercentRead=0, ___ExpirationStatus=3 '
                         'where BookID is Null and ContentID =?',t)
                 except Exception as e:
-                    if 'no such column' not in unicode_type(e):
+                    if 'no such column' not in str(e):
                         raise
                     try:
                         cursor.execute('update content set ReadStatus=0, FirstTimeReading = \'true\', ___PercentRead=0 '
                             'where BookID is Null and ContentID =?',t)
                     except Exception as e:
-                        if 'no such column' not in unicode_type(e):
+                        if 'no such column' not in str(e):
                             raise
                         cursor.execute('update content set ReadStatus=0, FirstTimeReading = \'true\' '
                             'where BookID is Null and ContentID =?',t)
@@ -833,7 +833,7 @@ class KOBO(USBMS):
             cursor.execute(query)
         except Exception as e:
             debug_print('    Database Exception:  Unable to reset Shortlist list')
-            if 'no such column' not in unicode_type(e):
+            if 'no such column' not in str(e):
                 raise
         finally:
             cursor.close()
@@ -847,7 +847,7 @@ class KOBO(USBMS):
             cursor.execute('update content set FavouritesIndex=1 where BookID is Null and ContentID = ?', t)
         except Exception as e:
             debug_print('    Database Exception:  Unable set book as Shortlist')
-            if 'no such column' not in unicode_type(e):
+            if 'no such column' not in str(e):
                 raise
         finally:
             cursor.close()
@@ -1138,7 +1138,7 @@ class KOBO(USBMS):
 
     def get_annotations(self, path_map):
         from calibre.devices.kobo.bookmark import Bookmark
-        EPUB_FORMATS = [u'epub']
+        EPUB_FORMATS = ['epub']
         epub_formats = set(EPUB_FORMATS)
 
         def get_storage():
@@ -1519,21 +1519,21 @@ class KOBOTOUCH(KOBO):
         self.plugboards = self.plugboard_func = None
 
     def initialize(self):
-        super(KOBOTOUCH, self).initialize()
+        super().initialize()
         self.bookshelvelist = []
 
     def get_device_information(self, end_session=True):
         self.set_device_name()
-        return super(KOBOTOUCH, self).get_device_information(end_session)
+        return super().get_device_information(end_session)
 
     def open_linux(self):
-        super(KOBOTOUCH, self).open_linux()
+        super().open_linux()
 
         self.swap_drives_if_needed()
 
     def open_osx(self):
         # Just dump some info to the logs.
-        super(KOBOTOUCH, self).open_osx()
+        super().open_osx()
 
         # Wrap some debugging output in a try/except so that it is unlikely to break things completely.
         try:
@@ -1808,7 +1808,7 @@ class KOBOTOUCH(KOBO):
                                 debug_print('KoboTouch:update_booklist - book file does not exist. ContentID="%s"'%ContentID)
 
                     except Exception as e:
-                        debug_print("KoboTouch:update_booklist - exception creating book: '%s'"%unicode_type(e))
+                        debug_print("KoboTouch:update_booklist - exception creating book: '%s'"%str(e))
                         debug_print("        prefix: ", prefix, "lpath: ", lpath, "title: ", title, "authors: ", authors,
                                     "MimeType: ", MimeType, "DateCreated: ", DateCreated, "ContentType: ", ContentType, "ImageID: ", ImageID)
                         raise
@@ -1870,7 +1870,7 @@ class KOBOTOUCH(KOBO):
                 bookshelves.append(row['ShelfName'])
 
             cursor.close()
-#            debug_print("KoboTouch:get_bookshelvesforbook - count bookshelves=" + unicode_type(count_bookshelves))
+#            debug_print("KoboTouch:get_bookshelvesforbook - count bookshelves=" + str(count_bookshelves))
             return bookshelves
 
         self.debug_index = 0
@@ -1963,7 +1963,7 @@ class KOBOTOUCH(KOBO):
             try:
                 cursor.execute(query)
             except Exception as e:
-                err = unicode_type(e)
+                err = str(e)
                 if not (any_in(err, '___ExpirationStatus', 'FavouritesIndex', 'Accessibility', 'IsDownloaded', 'Series', 'ExternalId')):
                     raise
                 query= ('SELECT Title, Attribution, DateCreated, ContentID, MimeType, ContentType, '
@@ -2049,7 +2049,7 @@ class KOBOTOUCH(KOBO):
         path = ContentID
 
         if not externalId:
-            return super(KOBOTOUCH, self).path_from_contentid(ContentID, ContentType, MimeType, oncard)
+            return super().path_from_contentid(ContentID, ContentType, MimeType, oncard)
 
         if oncard == 'cardb':
             print('path from_contentid cardb')
@@ -2099,13 +2099,13 @@ class KOBOTOUCH(KOBO):
                 from css_parser import parseFile as cssparseFile
                 try:
                     extra_sheet = cssparseFile(extra_css_path)
-                    debug_print("KoboTouch:get_extra_css: Using extra CSS in {0} ({1} rules)".format(extra_css_path, len(extra_sheet.cssRules)))
+                    debug_print("KoboTouch:get_extra_css: Using extra CSS in {} ({} rules)".format(extra_css_path, len(extra_sheet.cssRules)))
                     if len(extra_sheet.cssRules) ==0:
                         debug_print("KoboTouch:get_extra_css: Extra CSS file has no valid rules. CSS will not be modified.")
                         extra_sheet = None
                 except Exception as e:
-                    debug_print("KoboTouch:get_extra_css: Problem parsing extra CSS file {0}".format(extra_css_path))
+                    debug_print("KoboTouch:get_extra_css: Problem parsing extra CSS file {}".format(extra_css_path))
-                    debug_print("KoboTouch:get_extra_css: Exception {0}".format(e))
+                    debug_print("KoboTouch:get_extra_css: Exception {}".format(e))
 
         # create dictionary of features enabled in kobo extra css
         self.extra_css_options = {}
@@ -2136,16 +2136,16 @@ class KOBOTOUCH(KOBO):
             self.extra_sheet = self.get_extra_css()
             i = 0
             for file, n, mi in zip(files, names, metadata):
-                debug_print("KoboTouch:upload_books: Processing book: {0} by {1}".format(mi.title, " and ".join(mi.authors)))
+                debug_print("KoboTouch:upload_books: Processing book: {} by {}".format(mi.title, " and ".join(mi.authors)))
                 debug_print("KoboTouch:upload_books: file=%s, name=%s" % (file, n))
-                self.report_progress(i / float(len(files)), "Processing book: {0} by {1}".format(mi.title, " and ".join(mi.authors)))
+                self.report_progress(i / float(len(files)), "Processing book: {} by {}".format(mi.title, " and ".join(mi.authors)))
                 mi.kte_calibre_name = n
                 self._modify_epub(file, mi)
                 i += 1
 
         self.report_progress(0, 'Working...')
 
-        result = super(KOBOTOUCH, self).upload_books(files, names, on_card, end_session, metadata)
+        result = super().upload_books(files, names, on_card, end_session, metadata)
 #        debug_print('KoboTouch:upload_books - result=', result)
 
         if self.dbversion >= 53:
@@ -2174,12 +2174,12 @@ class KOBOTOUCH(KOBO):
 
                     cursor.close()
             except Exception as e:
-                debug_print('KoboTouch:upload_books - Exception:  %s'%unicode_type(e))
+                debug_print('KoboTouch:upload_books - Exception:  %s'%str(e))
 
         return result
 
     def _modify_epub(self, book_file, metadata, container=None):
-        debug_print("KoboTouch:_modify_epub:Processing {0} - {1}".format(metadata.author_sort, metadata.title))
+        debug_print("KoboTouch:_modify_epub:Processing {} - {}".format(metadata.author_sort, metadata.title))
 
         # Currently only modifying CSS, so if no stylesheet, don't do anything
         if not self.extra_sheet:
@@ -2200,9 +2200,9 @@ class KOBOTOUCH(KOBO):
 
                 # future css mods may be epub/kepub specific, so pass file extension arg
                 fileext = os.path.splitext(book_file)[-1].lower()
-                debug_print("KoboTouch:_modify_epub: Modifying {0}".format(cssname))
+                debug_print("KoboTouch:_modify_epub: Modifying {}".format(cssname))
                 if self._modify_stylesheet(newsheet, fileext):
-                    debug_print("KoboTouch:_modify_epub:CSS rules {0} -> {1} ({2})".format(oldrules, len(newsheet.cssRules), cssname))
+                    debug_print("KoboTouch:_modify_epub:CSS rules {} -> {} ({})".format(oldrules, len(newsheet.cssRules), cssname))
                     container.dirty(cssname)
                     is_dirty = True
 
@@ -2256,8 +2256,8 @@ class KOBOTOUCH(KOBO):
                 container = get_container(book_file)
                 container.css_preprocessor = DummyCSSPreProcessor()
             except Exception as e:
-                debug_print("KoboTouch:create_container: exception from get_container {0} - {1}".format(metadata.author_sort, metadata.title))
+                debug_print("KoboTouch:create_container: exception from get_container {} - {}".format(metadata.author_sort, metadata.title))
-                debug_print("KoboTouch:create_container: exception is: {0}".format(e))
+                debug_print("KoboTouch:create_container: exception is: {}".format(e))
         else:
             commit_container = False
             debug_print("KoboTouch:create_container: received container")
@@ -2277,7 +2277,7 @@ class KOBOTOUCH(KOBO):
             pass
 
     def delete_via_sql(self, ContentID, ContentType):
-        imageId = super(KOBOTOUCH, self).delete_via_sql(ContentID, ContentType)
+        imageId = super().delete_via_sql(ContentID, ContentType)
 
         if self.dbversion >= 53:
             debug_print('KoboTouch:delete_via_sql: ContentID="%s"'%ContentID, 'ContentType="%s"'%ContentType)
@@ -2318,7 +2318,7 @@ class KOBOTOUCH(KOBO):
                     debug_print('KoboTouch:delete_via_sql: finished SQL')
                 debug_print('KoboTouch:delete_via_sql: After SQL, no exception')
             except Exception as e:
-                debug_print('KoboTouch:delete_via_sql - Database Exception:  %s'%unicode_type(e))
+                debug_print('KoboTouch:delete_via_sql - Database Exception:  %s'%str(e))
 
         debug_print('KoboTouch:delete_via_sql: imageId="%s"'%imageId)
         if imageId is None:
@@ -2383,7 +2383,7 @@ class KOBOTOUCH(KOBO):
     def get_content_type_from_path(self, path):
         ContentType = 6
         if self.fwversion < (1, 9, 17):
-            ContentType = super(KOBOTOUCH, self).get_content_type_from_path(path)
+            ContentType = super().get_content_type_from_path(path)
         return ContentType
 
     def get_content_type_from_extension(self, extension):
@@ -2391,7 +2391,7 @@ class KOBOTOUCH(KOBO):
         # With new firmware, ContentType appears to be 6 for all types of sideloaded books.
         ContentType = 6
         if self.fwversion < (1,9,17):
-            ContentType = super(KOBOTOUCH, self).get_content_type_from_extension(extension)
+            ContentType = super().get_content_type_from_extension(extension)
         return ContentType
 
     def set_plugboards(self, plugboards, pb_func):
@@ -2451,7 +2451,7 @@ class KOBOTOUCH(KOBO):
 
             if self.manage_collections:
                 if collections:
-                    # debug_print("KoboTouch:update_device_database_collections - length collections=" + unicode_type(len(collections)))
+                    # debug_print("KoboTouch:update_device_database_collections - length collections=" + str(len(collections)))
 
                     # Need to reset the collections outside the particular loops
                     # otherwise the last item will not be removed
@@ -2621,7 +2621,7 @@ class KOBOTOUCH(KOBO):
                 self.keep_cover_aspect, self.letterbox_fs_covers, self.png_covers,
                 letterbox_color=self.letterbox_fs_covers_color)
         except Exception as e:
-            debug_print('KoboTouch: FAILED to upload cover=%s Exception=%s'%(filepath, unicode_type(e)))
+            debug_print('KoboTouch: FAILED to upload cover=%s Exception=%s'%(filepath, str(e)))
 
     def imageid_from_contentid(self, ContentID):
         ImageID = ContentID.replace('/', '_')
@@ -2831,7 +2831,7 @@ class KOBOTOUCH(KOBO):
                                 f.write(data)
                                 fsync(f)
         except Exception as e:
-            err = unicode_type(e)
+            err = str(e)
             debug_print("KoboTouch:_upload_cover - Exception string: %s"%err)
             raise
 
@@ -2978,7 +2978,7 @@ class KOBOTOUCH(KOBO):
 #            count_bookshelves = i + 1
 
         cursor.close()
-#        debug_print("KoboTouch:get_bookshelflist - count bookshelves=" + unicode_type(count_bookshelves))
+#        debug_print("KoboTouch:get_bookshelflist - count bookshelves=" + str(count_bookshelves))
 
         return bookshelves
 
@@ -3062,7 +3062,7 @@ class KOBOTOUCH(KOBO):
             cursor.execute(addquery, add_values)
         elif result['_IsDeleted'] == 'true':
             debug_print("KoboTouch:check_for_bookshelf - Shelf '%s' is deleted - undeleting. result['_IsDeleted']='%s'" % (
-                bookshelf_name, unicode_type(result['_IsDeleted'])))
+                bookshelf_name, str(result['_IsDeleted'])))
             cursor.execute(updatequery, test_values)
 
         cursor.close()
@@ -3329,7 +3329,7 @@ class KOBOTOUCH(KOBO):
 
     @classmethod
     def _config(cls):
-        c = super(KOBOTOUCH, cls)._config()
+        c = super()._config()
 
         c.add_opt('manage_collections', default=True)
         c.add_opt('collections_columns', default='')
@@ -3819,7 +3819,7 @@ class KOBOTOUCH(KOBO):
         try:
             is_debugging = len(self.debugging_title) > 0 and title.lower().find(self.debugging_title.lower()) >= 0 or len(title) == 0
         except:
-            debug_print(("KoboTouch::is_debugging_title - Exception checking debugging title for title '{0}'.").format(title))
+            debug_print(("KoboTouch::is_debugging_title - Exception checking debugging title for title '{}'.").format(title))
             is_debugging = False
 
         return is_debugging
@@ -3864,7 +3864,7 @@ class KOBOTOUCH(KOBO):
 
     def __str__(self, *args, **kwargs):
         options = ', '.join(['%s: %s' % (x.name, self.get_pref(x.name)) for x in self._config().preferences])
-        return u"Driver:%s, Options - %s" % (self.name, options)
+        return "Driver:%s, Options - %s" % (self.name, options)
 
 
 if __name__ == '__main__':

src/calibre/devices/kobo/kobotouch_config.py

@@ -16,7 +16,6 @@ from calibre.devices.usbms.driver import debug_print
 from calibre.gui2 import error_dialog
 from calibre.gui2.widgets2 import ColorButton
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
-from polyglot.builtins import unicode_type
 
 
 def wrap_msg(msg):
@@ -40,7 +39,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
                     must_read_metadata, supports_use_author_sort,
                     extra_customization_message, device, extra_customization_choices=None, parent=None):
 
-        super(KOBOTOUCHConfig, self).__init__(device_settings, all_formats, supports_subdirs,
+        super().__init__(device_settings, all_formats, supports_subdirs,
                     must_read_metadata, supports_use_author_sort,
                     extra_customization_message, device, extra_customization_choices, parent)
 
@@ -66,7 +65,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
         return self._device()
 
     def validate(self):
-        validated = super(KOBOTOUCHConfig, self).validate()
+        validated = super().validate()
         validated &= self.tab2.validate()
         return validated
 
@@ -96,7 +95,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
 
     def commit(self):
         debug_print("KOBOTOUCHConfig::commit: start")
-        p = super(KOBOTOUCHConfig, self).commit()
+        p = super().commit()
 
         p['manage_collections'] = self.manage_collections
         p['create_collections'] = self.create_collections
@@ -128,7 +127,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
 
         p['support_newer_firmware'] = self.support_newer_firmware
         p['debugging_title'] = self.debugging_title
-        p['driver_version'] = '.'.join([unicode_type(i) for i in self.device.version])
+        p['driver_version'] = '.'.join([str(i) for i in self.device.version])
 
         return p
 
@@ -136,7 +135,7 @@ class KOBOTOUCHConfig(TabbedDeviceConfig):
 class Tab1Config(DeviceConfigTab):  # {{{
 
     def __init__(self, parent, device):
-        super(Tab1Config, self).__init__(parent)
+        super().__init__(parent)
 
         self.l = QVBoxLayout(self)
         self.setLayout(self.l)
@@ -160,7 +159,7 @@ class Tab1Config(DeviceConfigTab):  # {{{
 class Tab2Config(DeviceConfigTab):  # {{{
 
     def __init__(self, parent, device):
-        super(Tab2Config, self).__init__(parent)
+        super().__init__(parent)
 
         self.l = QVBoxLayout(self)
         self.setLayout(self.l)
@@ -188,7 +187,7 @@ class Tab2Config(DeviceConfigTab):  # {{{
 class BookUploadsGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(BookUploadsGroupBox, self).__init__(parent, device)
+        super().__init__(parent, device)
         self.setTitle(_("Uploading of books"))
 
         self.options_layout = QGridLayout()
@@ -230,7 +229,7 @@ class BookUploadsGroupBox(DeviceOptionsGroupBox):
 class CollectionsGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(CollectionsGroupBox, self).__init__(parent, device)
+        super().__init__(parent, device)
         self.setTitle(_("Collections"))
 
         self.options_layout = QGridLayout()
@@ -297,7 +296,7 @@ class CollectionsGroupBox(DeviceOptionsGroupBox):
 class CoversGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(CoversGroupBox, self).__init__(parent, device)
+        super().__init__(parent, device)
         self.setTitle(_("Upload covers"))
 
         self.options_layout = QGridLayout()
@@ -416,7 +415,7 @@ class CoversGroupBox(DeviceOptionsGroupBox):
 class DeviceListGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(DeviceListGroupBox, self).__init__(parent, device)
+        super().__init__(parent, device)
         self.setTitle(_("Show as on device"))
 
         self.options_layout = QGridLayout()
@@ -466,7 +465,7 @@ class DeviceListGroupBox(DeviceOptionsGroupBox):
 class AdvancedGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(AdvancedGroupBox, self).__init__(parent, device, _("Advanced options"))
+        super().__init__(parent, device, _("Advanced options"))
 #         self.setTitle(_("Advanced Options"))
 
         self.options_layout = QGridLayout()
@@ -480,7 +479,7 @@ class AdvancedGroupBox(DeviceOptionsGroupBox):
                               'to perform full read-write functionality - Here be Dragons!! '
                               'Enable only if you are comfortable with restoring your kobo '
                               'to factory defaults and testing software. '
-                              'This driver supports firmware V2.x.x and DBVersion up to ') + unicode_type(
+                              'This driver supports firmware V2.x.x and DBVersion up to ') + str(
                                   device.supported_dbversion), device.get_pref('support_newer_firmware')
                              )
 
@@ -515,7 +514,7 @@ class AdvancedGroupBox(DeviceOptionsGroupBox):
 class MetadataGroupBox(DeviceOptionsGroupBox):
 
     def __init__(self, parent, device):
-        super(MetadataGroupBox, self).__init__(parent, device)
+        super().__init__(parent, device)
         self.setTitle(_("Update metadata on the device"))
 
         self.options_layout = QGridLayout()
@@ -638,7 +637,7 @@ class TemplateConfig(QWidget):  # {{{
 
     @property
     def template(self):
-        return unicode_type(self.t.text()).strip()
+        return str(self.t.text()).strip()
 
     @template.setter
     def template(self, template):
@@ -660,7 +659,7 @@ class TemplateConfig(QWidget):  # {{{
         except Exception as err:
             error_dialog(self, _('Invalid template'),
                     '<p>'+_('The template "%s" is invalid:')%tmpl +
-                    '<br>'+unicode_type(err), show=True)
+                    '<br>'+str(err), show=True)
 
             return False
 # }}}

src/calibre/devices/mime.py

@@ -1,4 +1,3 @@
-
 __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'

src/calibre/devices/mtp/books.py

@@ -46,7 +46,7 @@ class Book(Metadata):
         Metadata.__init__(self, _('Unknown'), other=other)
         self.storage_id, self.lpath = storage_id, lpath
         self.lpath = self.path = self.lpath.replace(os.sep, '/')
-        self.mtp_relpath = tuple([icu_lower(x) for x in self.lpath.split('/')])
+        self.mtp_relpath = tuple(icu_lower(x) for x in self.lpath.split('/'))
         self.datetime = utcnow().timetuple()
         self.thumbail = None
 

src/calibre/devices/mtp/driver.py

@@ -16,7 +16,7 @@ from calibre.devices.mtp.base import debug
 from calibre.devices.mtp.defaults import DeviceDefaults
 from calibre.ptempfile import SpooledTemporaryFile, PersistentTemporaryDirectory
 from calibre.utils.filenames import shorten_components_to
-from polyglot.builtins import iteritems, itervalues, unicode_type, zip, as_bytes
+from polyglot.builtins import iteritems, itervalues, as_bytes
 
 BASE = importlib.import_module('calibre.devices.mtp.%s.driver'%(
     'windows' if iswindows else 'unix')).MTP_DEVICE
@@ -76,7 +76,7 @@ class MTP_DEVICE(BASE):
 
     def is_folder_ignored(self, storage_or_storage_id, path,
                           ignored_folders=None):
-        storage_id = unicode_type(getattr(storage_or_storage_id, 'object_id',
+        storage_id = str(getattr(storage_or_storage_id, 'object_id',
                              storage_or_storage_id))
         lpath = tuple(icu_lower(name) for name in path)
         if ignored_folders is None:
@@ -168,14 +168,14 @@ class MTP_DEVICE(BASE):
                 traceback.print_exc()
                 dinfo = {}
         if dinfo.get('device_store_uuid', None) is None:
-            dinfo['device_store_uuid'] = unicode_type(uuid.uuid4())
+            dinfo['device_store_uuid'] = str(uuid.uuid4())
         if dinfo.get('device_name', None) is None:
             dinfo['device_name'] = self.current_friendly_name
         if name is not None:
             dinfo['device_name'] = name
         dinfo['location_code'] = location_code
         dinfo['last_library_uuid'] = getattr(self, 'current_library_uuid', None)
-        dinfo['calibre_version'] = '.'.join([unicode_type(i) for i in numeric_version])
+        dinfo['calibre_version'] = '.'.join([str(i) for i in numeric_version])
         dinfo['date_last_connected'] = isoformat(now())
         dinfo['mtp_prefix'] = storage.storage_prefix
         raw = as_bytes(json.dumps(dinfo, default=to_json))

src/calibre/devices/mtp/filesystem_cache.py

@@ -9,7 +9,7 @@ __docformat__ = 'restructuredtext en'
 import weakref, sys, json
 from collections import deque
 from operator import attrgetter
-from polyglot.builtins import itervalues, map, unicode_type
+from polyglot.builtins import itervalues
 from datetime import datetime
 
 from calibre import human_readable, prints, force_unicode
@@ -73,7 +73,7 @@ class FileOrFolder:
     def __repr__(self):
         name = 'Folder' if self.is_folder else 'File'
         try:
-            path = unicode_type(self.full_path)
+            path = str(self.full_path)
         except:
             path = ''
         datum = 'size=%s'%(self.size)
@@ -108,10 +108,8 @@ class FileOrFolder:
         return tuple(parts)
 
     def __iter__(self):
-        for e in self.folders:
+        yield from self.folders
-            yield e
+        yield from self.files
-        for e in self.files:
-            yield e
 
     def add_child(self, entry):
         ans = FileOrFolder(entry, self.fs_cache())

src/calibre/devices/mtp/test.py

@@ -12,7 +12,6 @@ from calibre.constants import iswindows, islinux
 from calibre.utils.icu import lower
 from calibre.devices.mtp.driver import MTP_DEVICE
 from calibre.devices.scanner import DeviceScanner
-from polyglot.builtins import range
 
 
 class ProgressCallback:

src/calibre/devices/mtp/unix/driver.py

@@ -15,7 +15,6 @@ from calibre.constants import islinux, ismacos
 from calibre.ptempfile import SpooledTemporaryFile
 from calibre.devices.errors import OpenFailed, DeviceError, BlacklistedDevice, OpenActionNeeded
 from calibre.devices.mtp.base import MTPDeviceBase, synchronous, debug
-from polyglot.builtins import unicode_type
 
 MTPDevice = namedtuple('MTPDevice', 'busnum devnum vendor_id product_id '
         'bcd serial manufacturer product')
@@ -76,7 +75,7 @@ class MTP_DEVICE(MTPDeviceBase):
                     traceback.print_stack()
                 return False
         if debug is not None and ans:
-            debug('Device {0} claims to be an MTP device in the IOKit registry'.format(d))
+            debug('Device {} claims to be an MTP device in the IOKit registry'.format(d))
         return bool(ans)
 
     def set_debug_level(self, lvl):
@@ -222,7 +221,7 @@ class MTP_DEVICE(MTPDeviceBase):
         try:
             storage = sorted(self.dev.storage_info, key=operator.itemgetter('id'))
         except self.libmtp.MTPError as e:
-            if "The device has no storage information." in unicode_type(e):
+            if "The device has no storage information." in str(e):
                 # This happens on newer Android devices while waiting for
                 # the user to allow access. Apparently what happens is
                 # that when the user clicks allow, the device disconnects
@@ -317,7 +316,7 @@ class MTP_DEVICE(MTPDeviceBase):
                     storage.append({'id':sid, 'size':capacity,
                         'is_folder':True, 'name':name, 'can_delete':False,
                         'is_system':True})
-                    self._currently_getting_sid = unicode_type(sid)
+                    self._currently_getting_sid = str(sid)
                     items, errs = self.dev.get_filesystem(sid,
                             partial(self._filesystem_callback, {}))
                     all_items.extend(items), all_errs.extend(errs)

src/calibre/devices/mtp/unix/sysfs.py

@@ -31,7 +31,7 @@ class MTPDetect:
             try:
                 with lopen(x, 'rb') as f:
                     return f.read()
-            except EnvironmentError:
+            except OSError:
                 pass
 
         ipath = os.path.join(self.base, '{0}-*/{0}-*/interface'.format(dev.busnum))
@@ -44,7 +44,7 @@ class MTPDetect:
             try:
                 if raw and int(raw) == dev.devnum:
                     if debug is not None:
-                        debug('Unknown device {0} claims to be an MTP device'
+                        debug('Unknown device {} claims to be an MTP device'
                               .format(dev))
                     return True
             except (ValueError, TypeError):

src/calibre/devices/mtp/windows/driver.py

@@ -8,7 +8,7 @@ __docformat__ = 'restructuredtext en'
 
 import time, threading, traceback
 from functools import wraps, partial
-from polyglot.builtins import iteritems, itervalues, unicode_type, zip
+from polyglot.builtins import iteritems, itervalues
 from itertools import chain
 
 from calibre import as_unicode, prints, force_unicode
@@ -268,7 +268,7 @@ class MTP_DEVICE(MTPDeviceBase):
                         break
                 storage = {'id':storage_id, 'size':capacity, 'name':name,
                         'is_folder':True, 'can_delete':False, 'is_system':True}
-                self._currently_getting_sid = unicode_type(storage_id)
+                self._currently_getting_sid = str(storage_id)
                 id_map = self.dev.get_filesystem(storage_id, partial(
                         self._filesystem_callback, {}))
                 for x in itervalues(id_map):

src/calibre/devices/nook/driver.py

@@ -111,7 +111,7 @@ class NOOK_COLOR(NOOK):
             self.EBOOK_DIR_MAIN = 'NOOK/My Files'
             try:
                 os.makedirs(os.path.join(self._main_prefix, *self.EBOOK_DIR_MAIN.split('/')))
-            except EnvironmentError as err:
+            except OSError as err:
                 if err.errno != errno.EEXIST:
                     self.EBOOK_DIR_MAIN = 'NOOK'
 

src/calibre/devices/nuut2/__init__.py

@@ -1 +0,0 @@
-

src/calibre/devices/paladin/driver.py

@@ -110,7 +110,7 @@ class PALADIN(USBMS):
                 for i, row in enumerate(cursor):
                     try:
                         comp_date = int(os.path.getmtime(self.normalize_path(prefix + row[0])) * 1000)
-                    except (OSError, IOError, TypeError):
+                    except (OSError, TypeError):
                         # In case the db has incorrect path info
                         continue
                     device_date = int(row[1])

src/calibre/devices/prs505/__init__.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 

src/calibre/devices/prs505/driver.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'

src/calibre/devices/prs505/sony_cache.py

@@ -17,7 +17,6 @@ from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.metadata import authors_to_string, title_sort, \
                                     authors_to_sort_string
 from polyglot.binary import from_base64_bytes
-from polyglot.builtins import unicode_type, zip
 
 '''
 cacheExt.xml
@@ -66,8 +65,8 @@ INVERSE_MONTH_MAP = dict(zip(MONTH_MAP.values(), MONTH_MAP.keys()))
 def strptime(src):
     src = src.strip()
     src = src.split()
-    src[0] = unicode_type(DAY_MAP[src[0][:-1]])+','
+    src[0] = str(DAY_MAP[src[0][:-1]])+','
-    src[2] = unicode_type(MONTH_MAP[src[2]])
+    src[2] = str(MONTH_MAP[src[2]])
     return time.strptime(' '.join(src), '%w, %d %m %Y %H:%M:%S %Z')
 
 
@@ -84,7 +83,7 @@ def strftime(epoch, zone=time.localtime):
 
 def uuid():
     from uuid import uuid4
-    return unicode_type(uuid4()).replace('-', '', 1).upper()
+    return str(uuid4()).replace('-', '', 1).upper()
 
 # }}}
 
@@ -197,8 +196,8 @@ class XMLCache:
                     playlist.set('title', title)
                 if title in seen:
                     for i in range(2, 1000):
-                        if title+unicode_type(i) not in seen:
+                        if title+str(i) not in seen:
-                            title = title+unicode_type(i)
+                            title = title+str(i)
                             playlist.set('title', title)
                             seen.add(title)
                             break
@@ -271,7 +270,7 @@ class XMLCache:
                 nsmap=root.nsmap, attrib={
                     'uuid' : uuid(),
                     'title': title,
-                    'id'   : unicode_type(self.max_id(root)+1),
+                    'id'   : str(self.max_id(root)+1),
                     'sourceid': '1'
                     })
         root.append(ans)
@@ -310,13 +309,13 @@ class XMLCache:
         def ensure_media_xml_base_ids(root):
             for num, tag in enumerate(('library', 'watchSpecial')):
                 for x in root.xpath('//*[local-name()="%s"]'%tag):
-                    x.set('id', unicode_type(num))
+                    x.set('id', str(num))
 
         def rebase_ids(root, base, sourceid, pl_sourceid):
             'Rebase all ids and also make them consecutive'
             for item in root.xpath('//*[@sourceid]'):
                 sid = pl_sourceid if item.tag.endswith('playlist') else sourceid
-                item.set('sourceid', unicode_type(sid))
+                item.set('sourceid', str(sid))
             # Only rebase ids of nodes that are immediate children of the
             # record root (that way playlist/itemnodes are unaffected
             items = root.xpath('child::*[@id]')
@@ -326,8 +325,8 @@ class XMLCache:
                 old = int(item.get('id'))
                 new = base + i
                 if old != new:
-                    item.set('id', unicode_type(new))
+                    item.set('id', str(new))
-                    idmap[unicode_type(old)] = unicode_type(new)
+                    idmap[str(old)] = str(new)
             return idmap
 
         self.prune_empty_playlists()
@@ -356,7 +355,7 @@ class XMLCache:
 
         last_bl = max(self.roots.keys())
         max_id = self.max_id(self.roots[last_bl])
-        self.roots[0].set('nextID', unicode_type(max_id+1))
+        self.roots[0].set('nextID', str(max_id+1))
         debug_print('Finished running fix_ids()')
 
     # }}}
@@ -513,7 +512,7 @@ class XMLCache:
             # Ensure each book has an ID.
             for rec in records:
                 if rec.get('id', None) is None:
-                    rec.set('id', unicode_type(self.max_id(root)+1))
+                    rec.set('id', str(self.max_id(root)+1))
             ids = [x.get('id', None) for x in records]
             # Given that we set the ids, there shouldn't be any None's. But
             # better to be safe...
@@ -570,7 +569,7 @@ class XMLCache:
         id_ = self.max_id(root)+1
         attrib = {
                 'page':'0', 'part':'0','pageOffset':'0','scale':'0',
-                'id':unicode_type(id_), 'sourceid':'1', 'path':lpath}
+                'id':str(id_), 'sourceid':'1', 'path':lpath}
         ans = root.makeelement('{%s}text'%namespace, attrib=attrib, nsmap=root.nsmap)
         root.append(ans)
         return ans
@@ -589,7 +588,7 @@ class XMLCache:
         if thumbnail and thumbnail[-1]:
             ans.text = '\n' + '\t\t'
             t = root.makeelement('{%s}thumbnail'%namespace,
-                attrib={'width':unicode_type(thumbnail[0]), 'height':unicode_type(thumbnail[1])},
+                attrib={'width':str(thumbnail[0]), 'height':str(thumbnail[1])},
                 nsmap=root.nsmap)
             t.text = 'main_thumbnail.jpg'
             ans.append(t)
@@ -658,7 +657,7 @@ class XMLCache:
             date = strftime(timestamp, zone=tz)
             record.set('date', clean(date))
         try:
-            record.set('size', clean(unicode_type(os.stat(path).st_size)))
+            record.set('size', clean(str(os.stat(path).st_size)))
         except:
             record.set('size', '0')
         title = book.title if book.title else _('Unknown')
@@ -688,7 +687,7 @@ class XMLCache:
             record.set('sourceid', '1')
         if 'id' not in record.attrib:
             num = self.max_id(record.getroottree().getroot())
-            record.set('id', unicode_type(num+1))
+            record.set('id', str(num+1))
         return (gtz_count, ltz_count, use_tz_var)
     # }}}
 
@@ -759,7 +758,7 @@ class XMLCache:
         return m
 
     def book_by_lpath(self, lpath, root):
-        matches = root.xpath(u'//*[local-name()="text" and @path="%s"]'%lpath)
+        matches = root.xpath('//*[local-name()="text" and @path="%s"]'%lpath)
         if matches:
             return matches[0]
 

src/calibre/devices/prst1/driver.py

@@ -23,7 +23,7 @@ from calibre.devices.usbms.books import CollectionsBookList
 from calibre.devices.usbms.books import BookList
 from calibre.ebooks.metadata import authors_to_sort_string, authors_to_string
 from calibre.constants import islinux
-from polyglot.builtins import unicode_type, long_type
+from polyglot.builtins import long_type
 
 DBPATH = 'Sony_Reader/database/books.db'
 THUMBPATH = 'Sony_Reader/database/cache/books/%s/thumbnail/main_thumbnail.jpg'
@@ -170,7 +170,7 @@ class PRST1(USBMS):
 
         with closing(sqlite.connect(dbpath)) as connection:
             # Replace undecodable characters in the db instead of erroring out
-            connection.text_factory = lambda x: x if isinstance(x, unicode_type) else x.decode('utf-8', 'replace')
+            connection.text_factory = lambda x: x if isinstance(x, str) else x.decode('utf-8', 'replace')
 
             cursor = connection.cursor()
             # Query collections
@@ -199,7 +199,7 @@ class PRST1(USBMS):
                 for i, row in enumerate(cursor):
                     try:
                         comp_date = int(os.path.getmtime(self.normalize_path(prefix + row[0])) * 1000)
-                    except (OSError, IOError, TypeError):
+                    except (OSError, TypeError):
                         # In case the db has incorrect path info
                         continue
                     device_date = int(row[1])

src/calibre/devices/scanner.py

@@ -1,4 +1,3 @@
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 '''
@@ -13,7 +12,6 @@ from threading import Lock
 from calibre import prints, as_unicode
 from calibre.constants import (iswindows, ismacos, islinux, isfreebsd,
         isnetbsd)
-from polyglot.builtins import range
 
 osx_scanner = linux_scanner = freebsd_scanner = netbsd_scanner = None
 
@@ -41,12 +39,12 @@ _USBDevice = namedtuple('USBDevice',
 class USBDevice(_USBDevice):
 
     def __new__(cls, *args, **kwargs):
-        self = super(USBDevice, cls).__new__(cls, *args)
+        self = super().__new__(cls, *args)
         self.busnum = self.devnum = -1
         return self
 
     def __repr__(self):
-        return (u'USBDevice(busnum=%s, devnum=%s, '
+        return ('USBDevice(busnum=%s, devnum=%s, '
                 'vendor_id=0x%04x, product_id=0x%04x, bcd=0x%04x, '
                 'manufacturer=%s, product=%s, serial=%s)')%(
                 self.busnum, self.devnum, self.vendor_id, self.product_id,
@@ -142,15 +140,15 @@ class LinuxScanner:
             try:
                 dev.append(read(man).decode('utf-8'))
             except Exception:
-                dev.append(u'')
+                dev.append('')
             try:
                 dev.append(read(prod_string).decode('utf-8'))
             except Exception:
-                dev.append(u'')
+                dev.append('')
             try:
                 dev.append(read(serial).decode('utf-8'))
             except Exception:
-                dev.append(u'')
+                dev.append('')
 
             dev = USBDevice(*dev)
             try:

src/calibre/devices/smart_device_app/driver.py

@@ -47,7 +47,7 @@ from calibre.utils.mdns import (
 )
 from calibre.utils.socket_inheritance import set_socket_inherit
 from polyglot import queue
-from polyglot.builtins import as_bytes, iteritems, itervalues, unicode_type
+from polyglot.builtins import as_bytes, iteritems, itervalues
 
 
 def synchronous(tlockname):
@@ -125,13 +125,13 @@ class ConnectionListener(Thread):
                             content_server_port = ''
                             try:
                                 from calibre.srv.opts import server_config
-                                content_server_port = unicode_type(server_config().port)
+                                content_server_port = str(server_config().port)
                             except Exception:
                                 pass
                             message = (self.driver.ZEROCONF_CLIENT_STRING + ' (on ' +
-                                            unicode_type(socket.gethostname().partition('.')[0]) +
+                                            str(socket.gethostname().partition('.')[0]) +
                                             ');' + content_server_port +
-                                            ',' + unicode_type(self.driver.port)).encode('utf-8')
+                                            ',' + str(self.driver.port)).encode('utf-8')
                             self.driver._debug('received broadcast', packet, message)
                             self.driver.broadcast_socket.sendto(message, remote)
                         except:
@@ -164,7 +164,7 @@ class ConnectionListener(Thread):
 
                     except socket.timeout:
                         pass
-                    except socket.error:
+                    except OSError:
                         x = sys.exc_info()[1]
                         self.driver._debug('unexpected socket exception', x.args[0])
                         self._close_socket(device_socket)
@@ -414,7 +414,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                     if isinstance(a, dict):
                         printable = {}
                         for k,v in iteritems(a):
-                            if isinstance(v, (bytes, unicode_type)) and len(v) > 50:
+                            if isinstance(v, (bytes, str)) and len(v) > 50:
                                 printable[k] = 'too long'
                             else:
                                 printable[k] = v
@@ -436,14 +436,14 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
         if not isinstance(dinfo, dict):
             dinfo = {}
         if dinfo.get('device_store_uuid', None) is None:
-            dinfo['device_store_uuid'] = unicode_type(uuid.uuid4())
+            dinfo['device_store_uuid'] = str(uuid.uuid4())
         if dinfo.get('device_name') is None:
             dinfo['device_name'] = self.get_gui_name()
         if name is not None:
             dinfo['device_name'] = name
         dinfo['location_code'] = location_code
         dinfo['last_library_uuid'] = getattr(self, 'current_library_uuid', None)
-        dinfo['calibre_version'] = '.'.join([unicode_type(i) for i in numeric_version])
+        dinfo['calibre_version'] = '.'.join([str(i) for i in numeric_version])
         dinfo['date_last_connected'] = isoformat(now())
         dinfo['prefix'] = self.PREFIX
         return dinfo
@@ -495,9 +495,9 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
 
         from calibre.library.save_to_disk import config, get_components
         opts = config().parse()
-        if not isinstance(template, unicode_type):
+        if not isinstance(template, str):
             template = template.decode('utf-8')
-        app_id = unicode_type(getattr(mdata, 'application_id', ''))
+        app_id = str(getattr(mdata, 'application_id', ''))
         id_ = mdata.get('id', fname)
         extra_components = get_components(template, mdata, id_,
                 timefmt=opts.send_timefmt, length=maxlen-len(app_id)-1,
@@ -623,9 +623,9 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                     amt_sent = sock.send(s[sent_len:])
                 sock.settimeout(None)
                 if amt_sent <= 0:
-                    raise IOError('Bad write on socket')
+                    raise OSError('Bad write on socket')
                 sent_len += amt_sent
-            except socket.error as e:
+            except OSError as e:
                 self._debug('socket error', e, e.errno)
                 if e.args[0] != EAGAIN and e.args[0] != EINTR:
                     self._close_device_socket()
@@ -661,7 +661,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             self._debug('timeout communicating with device')
             self._close_device_socket()
             raise TimeoutError('Device did not respond in reasonable time')
-        except socket.error:
+        except OSError:
             self._debug('device went away')
             self._close_device_socket()
             raise ControlError(desc='Device closed the network connection')
@@ -689,7 +689,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             self._debug('timeout communicating with device')
             self._close_device_socket()
             raise TimeoutError('Device did not respond in reasonable time')
-        except socket.error:
+        except OSError:
             self._debug('device went away')
             self._close_device_socket()
             raise ControlError(desc='Device closed the network connection')
@@ -747,7 +747,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
         from calibre.utils.date import now, parse_date
         try:
             key = self._make_metadata_cache_key(uuid, ext_or_lpath)
-            if isinstance(lastmod, unicode_type):
+            if isinstance(lastmod, str):
                 if lastmod == 'None':
                     return None
                 lastmod = parse_date(lastmod)
@@ -936,7 +936,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                 sock.bind((ip_addr, port))
             else:
                 sock.bind(('', port))
-        except socket.error:
+        except OSError:
             self._debug('socket error on port', port)
             port = 0
         except:
@@ -1213,7 +1213,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
             return True
         except socket.timeout:
             self._close_device_socket()
-        except socket.error:
+        except OSError:
             x = sys.exc_info()[1]
             self._debug('unexpected socket exception', x.args[0])
             self._close_device_socket()
@@ -1909,7 +1909,7 @@ class SMART_DEVICE_APP(DeviceConfig, DevicePlugin):
                             'between 50 and 99. Forced to be %d.')%self.DEFAULT_THUMBNAIL_COMPRESSION_QUALITY
                 self._debug(message)
                 self.set_option('thumbnail_compression_quality',
-                                unicode_type(self.DEFAULT_THUMBNAIL_COMPRESSION_QUALITY))
+                                str(self.DEFAULT_THUMBNAIL_COMPRESSION_QUALITY))
 
             try:
                 self.listen_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

src/calibre/devices/teclast/driver.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'

src/calibre/devices/usbms/cli.py

@@ -54,7 +54,7 @@ class CLI:
         with dest:
             try:
                 shutil.copyfileobj(infile, dest)
-            except IOError:
+            except OSError:
                 print('WARNING: First attempt to send file to device failed')
                 time.sleep(0.2)
                 infile.seek(0)

src/calibre/devices/usbms/device.py

@@ -27,7 +27,7 @@ from calibre.devices.errors import DeviceError
 from calibre.devices.interface import DevicePlugin
 from calibre.devices.usbms.deviceconfig import DeviceConfig
 from calibre.utils.filenames import ascii_filename as sanitize
-from polyglot.builtins import iteritems, map, string_or_bytes
+from polyglot.builtins import iteritems, string_or_bytes
 
 if ismacos:
     osx_sanitize_name_pat = re.compile(r'[.-]')
@@ -296,7 +296,7 @@ class Device(DeviceConfig, DevicePlugin):
             try:
                 return subprocess.Popen(cmd,
                                     stdout=subprocess.PIPE).communicate()[0]
-            except IOError:  # Probably an interrupted system call
+            except OSError:  # Probably an interrupted system call
                 if i == 2:
                     raise
             time.sleep(2)
@@ -310,7 +310,7 @@ class Device(DeviceConfig, DevicePlugin):
             try:
                 return subprocess.Popen('mount',
                                     stdout=subprocess.PIPE).communicate()[0]
-            except IOError:  # Probably an interrupted system call
+            except OSError:  # Probably an interrupted system call
                 if i == 2:
                     raise
             time.sleep(2)
@@ -440,8 +440,7 @@ class Device(DeviceConfig, DevicePlugin):
                 isfile = os.path.isfile(p)
                 yield p, isfile
                 if not isfile:
-                    for y, q in walk(p):
+                    yield from walk(p)
-                        yield y, q
 
         def raw2num(raw):
             raw = raw.lower()

src/calibre/devices/usbms/deviceconfig.py

@@ -6,7 +6,6 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 from calibre.utils.config_base import Config, ConfigProxy
-from polyglot.builtins import unicode_type
 
 
 class DeviceConfig:
@@ -109,15 +108,15 @@ class DeviceConfig:
                     if hasattr(config_widget.opt_extra_customization[i], 'isChecked'):
                         ec.append(config_widget.opt_extra_customization[i].isChecked())
                     elif hasattr(config_widget.opt_extra_customization[i], 'currentText'):
-                        ec.append(unicode_type(config_widget.opt_extra_customization[i].currentText()).strip())
+                        ec.append(str(config_widget.opt_extra_customization[i].currentText()).strip())
                     else:
-                        ec.append(unicode_type(config_widget.opt_extra_customization[i].text()).strip())
+                        ec.append(str(config_widget.opt_extra_customization[i].text()).strip())
             else:
-                ec = unicode_type(config_widget.opt_extra_customization.text()).strip()
+                ec = str(config_widget.opt_extra_customization.text()).strip()
                 if not ec:
                     ec = None
             proxy['extra_customization'] = ec
-        st = unicode_type(config_widget.opt_save_template.text())
+        st = str(config_widget.opt_save_template.text())
         proxy['save_template'] = st
 
     @classmethod

src/calibre/devices/usbms/driver.py

@@ -21,7 +21,7 @@ from calibre.devices.usbms.cli import CLI
 from calibre.devices.usbms.device import Device
 from calibre.devices.usbms.books import BookList, Book
 from calibre.ebooks.metadata.book.json_codec import JsonCodec
-from polyglot.builtins import itervalues, unicode_type, string_or_bytes, zip
+from polyglot.builtins import itervalues, string_or_bytes
 
 
 def debug_print(*args, **kw):
@@ -68,8 +68,7 @@ def safe_walk(top, topdown=True, onerror=None, followlinks=False, maxdepth=128):
     for name in dirs:
         new_path = join(top, name)
         if followlinks or not islink(new_path):
-            for x in safe_walk(new_path, topdown, onerror, followlinks, maxdepth-1):
+            yield from safe_walk(new_path, topdown, onerror, followlinks, maxdepth-1)
-                yield x
     if not topdown:
         yield top, dirs, nondirs
 
@@ -107,14 +106,14 @@ class USBMS(CLI, Device):
         if not isinstance(dinfo, dict):
             dinfo = {}
         if dinfo.get('device_store_uuid', None) is None:
-            dinfo['device_store_uuid'] = unicode_type(uuid.uuid4())
+            dinfo['device_store_uuid'] = str(uuid.uuid4())
         if dinfo.get('device_name', None) is None:
             dinfo['device_name'] = self.get_gui_name()
         if name is not None:
             dinfo['device_name'] = name
         dinfo['location_code'] = location_code
         dinfo['last_library_uuid'] = getattr(self, 'current_library_uuid', None)
-        dinfo['calibre_version'] = '.'.join([unicode_type(i) for i in numeric_version])
+        dinfo['calibre_version'] = '.'.join([str(i) for i in numeric_version])
         dinfo['date_last_connected'] = isoformat(now())
         dinfo['prefix'] = prefix.replace('\\', '/')
         return dinfo
@@ -151,8 +150,8 @@ class USBMS(CLI, Device):
         if self._main_prefix is not None:
             try:
                 self.driveinfo['main'] = self._update_driveinfo_file(self._main_prefix, 'main')
-            except (IOError, OSError) as e:
+            except OSError as e:
-                raise IOError(_('Failed to access files in the main memory of'
+                raise OSError(_('Failed to access files in the main memory of'
                         ' your device. You should contact the device'
                         ' manufacturer for support. Common fixes are:'
                         ' try a different USB cable/USB port on your computer.'
@@ -164,8 +163,8 @@ class USBMS(CLI, Device):
                 self.driveinfo['A'] = self._update_driveinfo_file(self._card_a_prefix, 'A')
             if self._card_b_prefix is not None:
                 self.driveinfo['B'] = self._update_driveinfo_file(self._card_b_prefix, 'B')
-        except (IOError, OSError) as e:
+        except OSError as e:
-            raise IOError(_('Failed to access files on the SD card in your'
+            raise OSError(_('Failed to access files on the SD card in your'
                 ' device. This can happen for many reasons. The SD card may be'
                 ' corrupted, it may be too large for your device, it may be'
                 ' write-protected, etc. Try a different SD card, or reformat'

src/calibre/devices/utils.py

@@ -10,7 +10,6 @@ import os, time, re
 from functools import partial
 
 from calibre.devices.errors import DeviceError, WrongDestinationError, FreeSpaceError
-from polyglot.builtins import unicode_type
 
 
 def sanity_check(on_card, files, card_prefixes, free_space):
@@ -60,8 +59,8 @@ def build_template_regexp(template):
         template = template.rpartition('/')[2]
         return re.compile(re.sub('{([^}]*)}', f, template) + r'([_\d]*$)')
     except:
-        prints(u'Failed to parse template: %r'%template)
+        prints('Failed to parse template: %r'%template)
-        template = u'{title} - {authors}'
+        template = '{title} - {authors}'
         return re.compile(re.sub('{([^}]*)}', f, template) + r'([_\d]*$)')
 
 
@@ -91,15 +90,15 @@ def create_upload_path(mdata, fname, template, sanitize,
         except:
             today = time.localtime()
             date = (today[0], today[1], today[2])
-        template = u"{title}_%d-%d-%d" % date
+        template = "{title}_%d-%d-%d" % date
 
     fname = sanitize(fname)
     ext = path_type.splitext(fname)[1]
 
     opts = config().parse()
-    if not isinstance(template, unicode_type):
+    if not isinstance(template, str):
         template = template.decode('utf-8')
-    app_id = unicode_type(getattr(mdata, 'application_id', ''))
+    app_id = str(getattr(mdata, 'application_id', ''))
     id_ = mdata.get('id', fname)
     extra_components = get_components(template, mdata, id_,
             timefmt=opts.send_timefmt, length=maxlen-len(app_id)-1,

src/calibre/devices/winusb.py

@@ -13,7 +13,7 @@ from ctypes import (
 )
 from ctypes.wintypes import DWORD, WORD, ULONG, LPCWSTR, HWND, BOOL, LPWSTR, UINT, BYTE, HANDLE, USHORT
 from pprint import pprint, pformat
-from polyglot.builtins import iteritems, itervalues, map, filter
+from polyglot.builtins import iteritems, itervalues
 
 from calibre import prints, as_unicode
 
@@ -507,8 +507,7 @@ def iterchildren(parent_devinst):
 def iterdescendants(parent_devinst):
     for child in iterchildren(parent_devinst):
         yield child
-        for gc in iterdescendants(child):
+        yield from iterdescendants(child)
-            yield gc
 
 
 def iterancestors(devinst):

src/calibre/ebooks/BeautifulSoup.py

@@ -9,13 +9,12 @@ from bs4 import (  # noqa
     SoupStrainer, Tag, __version__
 )
 
-from polyglot.builtins import unicode_type
 
 
 def parse_html(markup):
     from calibre.ebooks.chardet import strip_encoding_declarations, xml_to_unicode, substitute_entites
     from calibre.utils.cleantext import clean_xml_chars
-    if isinstance(markup, unicode_type):
+    if isinstance(markup, str):
         markup = strip_encoding_declarations(markup)
         markup = substitute_entites(markup)
     else:

src/calibre/ebooks/__init__.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 
@@ -11,7 +9,6 @@ from various formats.
 import os, re, numbers, sys
 from calibre import prints
 from calibre.ebooks.chardet import xml_to_unicode
-from polyglot.builtins import unicode_type
 
 
 class ConversionError(Exception):
@@ -82,7 +79,7 @@ def extract_calibre_cover(raw, base, log):
     if matches is None:
         body = soup.find('body')
         if body is not None:
-            text = u''.join(map(unicode_type, body.findAll(text=True)))
+            text = ''.join(map(str, body.findAll(text=True)))
             if text.strip():
                 # Body has text, abort
                 return
@@ -152,7 +149,7 @@ def check_ebook_format(stream, current_guess):
 
 
 def normalize(x):
-    if isinstance(x, unicode_type):
+    if isinstance(x, str):
         import unicodedata
         x = unicodedata.normalize('NFC', x)
     return x

src/calibre/ebooks/azw4/reader.py

@@ -16,7 +16,6 @@ import os
 import re
 
 from calibre.ebooks.pdb.formatreader import FormatReader
-from polyglot.builtins import getcwd
 
 
 def unwrap(stream, output_path):
@@ -46,7 +45,7 @@ class Reader(FormatReader):
         if mo:
             data = mo.group()
 
-        pdf_n = os.path.join(getcwd(), 'tmp.pdf')
+        pdf_n = os.path.join(os.getcwd(), 'tmp.pdf')
         with open(pdf_n, 'wb') as pdf:
             pdf.write(data)
         from calibre.customize.ui import plugin_for_input_format

src/calibre/ebooks/chardet.py

@@ -7,7 +7,6 @@ __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import re, codecs, sys
-from polyglot.builtins import unicode_type
 
 _encoding_pats = (
     # XML declaration
@@ -34,8 +33,7 @@ class LazyEncodingPats:
         if pats is None:
             pats = tuple(compile_pats(binary))
             setattr(self, attr, pats)
-        for pat in pats:
+        yield from pats
-            yield pat
 
 
 lazy_encoding_pats = LazyEncodingPats()
@@ -52,7 +50,7 @@ def strip_encoding_declarations(raw, limit=50*1024, preserve_newlines=False):
         else:
             sub = lambda m: '\n' * m.group().count('\n')
     else:
-        sub = b'' if is_binary else u''
+        sub = b'' if is_binary else ''
     for pat in lazy_encoding_pats(is_binary):
         prefix = pat.sub(sub, prefix)
     raw = prefix + suffix
@@ -140,7 +138,7 @@ def force_encoding(raw, verbose, assume_utf8=False):
 
 
 def detect_xml_encoding(raw, verbose=False, assume_utf8=False):
-    if not raw or isinstance(raw, unicode_type):
+    if not raw or isinstance(raw, str):
         return raw, None
     for x in ('utf8', 'utf-16-le', 'utf-16-be'):
         bom = getattr(codecs, 'BOM_'+x.upper().replace('-16', '16').replace(
@@ -184,7 +182,7 @@ def xml_to_unicode(raw, verbose=False, strip_encoding_pats=False,
         return '', None
     raw, encoding = detect_xml_encoding(raw, verbose=verbose,
             assume_utf8=assume_utf8)
-    if not isinstance(raw, unicode_type):
+    if not isinstance(raw, str):
         raw = raw.decode(encoding, 'replace')
 
     if strip_encoding_pats:

src/calibre/ebooks/chm/reader.py

@@ -13,7 +13,7 @@ from calibre.ebooks.BeautifulSoup import BeautifulSoup, NavigableString
 from calibre.ebooks.chardet import xml_to_unicode
 from calibre.ebooks.metadata.toc import TOC
 from chm.chm import CHMFile, chmlib
-from polyglot.builtins import as_unicode, getcwd, unicode_type
+from polyglot.builtins import as_unicode
 
 
 def match_string(s1, s2_already_lowered):
@@ -43,7 +43,7 @@ class CHMReader(CHMFile):
 
     def __init__(self, input, log, input_encoding=None):
         CHMFile.__init__(self)
-        if isinstance(input, unicode_type):
+        if isinstance(input, str):
             enc = 'mbcs' if iswindows else filesystem_encoding
             try:
                 input = input.encode(enc)
@@ -113,7 +113,7 @@ class CHMReader(CHMFile):
     def get_encoding(self):
         return self.encoding_from_system_file or self.encoding_from_lcid or 'cp1252'
 
-    def _parse_toc(self, ul, basedir=getcwd()):
+    def _parse_toc(self, ul, basedir=os.getcwd()):
         toc = TOC(play_order=self._playorder, base_path=basedir, text='')
         self._playorder += 1
         for li in ul('li', recursive=False):
@@ -157,7 +157,7 @@ class CHMReader(CHMFile):
     def get_home(self):
         return self.GetFile(self.home)
 
-    def ExtractFiles(self, output_dir=getcwd(), debug_dump=False):
+    def ExtractFiles(self, output_dir=os.getcwd(), debug_dump=False):
         html_files = set()
         for path in self.Contents():
             fpath = path
@@ -192,7 +192,7 @@ class CHMReader(CHMFile):
             with lopen(lpath, 'r+b') as f:
                 data = f.read()
                 data = self._reformat(data, lpath)
-                if isinstance(data, unicode_type):
+                if isinstance(data, str):
                     data = data.encode('utf-8')
                 f.seek(0)
                 f.truncate()
@@ -336,5 +336,5 @@ class CHMReader(CHMFile):
         if not os.path.isdir(dir):
             os.makedirs(dir)
 
-    def extract_content(self, output_dir=getcwd(), debug_dump=False):
+    def extract_content(self, output_dir=os.getcwd(), debug_dump=False):
         self.ExtractFiles(output_dir=output_dir, debug_dump=debug_dump)

src/calibre/ebooks/comic/input.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
@@ -16,7 +14,6 @@ from calibre.ptempfile import PersistentTemporaryDirectory
 from calibre.utils.icu import numeric_sort_key
 from calibre.utils.ipc.server import Server
 from calibre.utils.ipc.job import ParallelJob
-from polyglot.builtins import unicode_type, map
 from polyglot.queue import Empty
 
 # If the specified screen has either dimension larger than this value, no image
@@ -29,7 +26,7 @@ def extract_comic(path_to_comic_file):
     Un-archive the comic file.
     '''
     tdir = PersistentTemporaryDirectory(suffix='_comic_extract')
-    if not isinstance(tdir, unicode_type):
+    if not isinstance(tdir, str):
         # Needed in case the zip file has wrongly encoded unicode file/dir
         # names
         tdir = tdir.decode(filesystem_encoding)

src/calibre/ebooks/compression/palmdoc.py

@@ -8,7 +8,6 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import io
 from struct import pack
 
-from polyglot.builtins import range
 from calibre_extensions import cPalmdoc
 
 

src/calibre/ebooks/compression/tcr.py

@@ -6,7 +6,7 @@ __copyright__ = '2009, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from polyglot.builtins import int_to_byte, range
+from polyglot.builtins import int_to_byte
 
 
 class TCRCompressor:

src/calibre/ebooks/conversion/cli.py

@@ -1,5 +1,3 @@
-
-
 __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
@@ -372,7 +370,7 @@ def main(args=sys.argv):
     parser, plumber = create_option_parser(args, log)
     opts, leftover_args = parser.parse_args(args)
     if len(leftover_args) > 3:
-        log.error('Extra arguments not understood:', u', '.join(leftover_args[3:]))
+        log.error('Extra arguments not understood:', ', '.join(leftover_args[3:]))
         return 1
     for x in ('read_metadata_from_opf', 'cover'):
         if getattr(opts, x, None) is not None:

src/calibre/ebooks/conversion/config.py

@@ -13,7 +13,6 @@ from calibre.utils.lock import ExclusiveFile
 from calibre import sanitize_file_name
 from calibre.customize.conversion import OptionRecommendation
 from calibre.customize.ui import available_output_formats
-from polyglot.builtins import unicode_type
 
 
 config_dir = os.path.join(config_dir, 'conversion')
@@ -71,7 +70,7 @@ class GuiRecommendations(dict):
 
     def __new__(cls, *args):
         dict.__new__(cls)
-        obj = super(GuiRecommendations, cls).__new__(cls, *args)
+        obj = super().__new__(cls, *args)
         obj.disabled_options = set()
         return obj
 
@@ -90,7 +89,7 @@ class GuiRecommendations(dict):
 
     def serialize(self):
         ans = json.dumps(self, indent=2, ensure_ascii=False)
-        if isinstance(ans, unicode_type):
+        if isinstance(ans, str):
             ans = ans.encode('utf-8')
         return b'json:' + ans
 

src/calibre/ebooks/conversion/plugins/azw4_input.py

@@ -5,8 +5,9 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, John Schember <john@nachtimwald.com>'
 __docformat__ = 'restructuredtext en'
 
+import os
+
 from calibre.customize.conversion import InputFormatPlugin
-from polyglot.builtins import getcwd
 
 
 class AZW4Input(InputFormatPlugin):
@@ -24,6 +25,6 @@ class AZW4Input(InputFormatPlugin):
 
         header = PdbHeaderReader(stream)
         reader = Reader(header, stream, log, options)
-        opf = reader.extract_content(getcwd())
+        opf = reader.extract_content(os.getcwd())
 
         return opf

src/calibre/ebooks/conversion/plugins/chm_input.py

@@ -1,5 +1,3 @@
-
-
 ''' CHM File decoding support '''
 __license__ = 'GPL v3'
 __copyright__  = '2008, Kovid Goyal <kovid at kovidgoyal.net>,' \
@@ -10,7 +8,7 @@ import os
 from calibre.customize.conversion import InputFormatPlugin
 from calibre.ptempfile import TemporaryDirectory
 from calibre.constants import filesystem_encoding
-from polyglot.builtins import unicode_type, as_bytes
+from polyglot.builtins import as_bytes
 
 
 class CHMInput(InputFormatPlugin):
@@ -37,7 +35,7 @@ class CHMInput(InputFormatPlugin):
 
         log.debug('Processing CHM...')
         with TemporaryDirectory('_chm2oeb') as tdir:
-            if not isinstance(tdir, unicode_type):
+            if not isinstance(tdir, str):
                 tdir = tdir.decode(filesystem_encoding)
             html_input = plugin_for_input_format('html')
             for opt in html_input.options:
@@ -128,7 +126,7 @@ class CHMInput(InputFormatPlugin):
         base = os.path.dirname(os.path.abspath(htmlpath))
 
         def unquote(x):
-            if isinstance(x, unicode_type):
+            if isinstance(x, str):
                 x = x.encode('utf-8')
             return _unquote(x).decode('utf-8')
 

src/calibre/ebooks/conversion/plugins/comic_input.py

@@ -1,5 +1,3 @@
-
-
 __license__   = 'GPL v3'
 __copyright__ = '2008, Kovid Goyal kovid@kovidgoyal.net'
 __docformat__ = 'restructuredtext en'
@@ -13,7 +11,6 @@ import shutil, textwrap, codecs, os
 from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
 from calibre import CurrentDir
 from calibre.ptempfile import PersistentTemporaryDirectory
-from polyglot.builtins import getcwd, map
 
 
 class ComicInput(InputFormatPlugin):
@@ -198,7 +195,7 @@ class ComicInput(InputFormatPlugin):
 
         mi  = MetaInformation(os.path.basename(stream.name).rpartition('.')[0],
             [_('Unknown')])
-        opf = OPFCreator(getcwd(), mi)
+        opf = OPFCreator(os.getcwd(), mi)
         entries = []
 
         def href(x):

src/calibre/ebooks/conversion/plugins/djvu_input.py

@@ -9,7 +9,6 @@ import os
 from io import BytesIO
 
 from calibre.customize.conversion import InputFormatPlugin
-from polyglot.builtins import getcwd
 
 
 class DJVUInput(InputFormatPlugin):
@@ -40,7 +39,7 @@ class DJVUInput(InputFormatPlugin):
         for opt in html_input.options:
             setattr(options, opt.option.name, opt.recommended_value)
         options.input_encoding = 'utf-8'
-        base = getcwd()
+        base = os.getcwd()
         htmlfile = os.path.join(base, 'index.html')
         c = 0
         while os.path.exists(htmlfile):

src/calibre/ebooks/conversion/plugins/epub_input.py

@@ -1,5 +1,3 @@
-
-
 __license__ = 'GPL 3'
 __copyright__ = '2009, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
@@ -8,7 +6,6 @@ import os, re, posixpath
 from itertools import cycle
 
 from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
-from polyglot.builtins import getcwd
 
 ADOBE_OBFUSCATION =  'http://ns.adobe.com/pdf/enc#RC'
 IDPF_OBFUSCATION = 'http://www.idpf.org/2008/embedding'
@@ -246,7 +243,7 @@ class EPUBInput(InputFormatPlugin):
                     path = attr(r, 'full-path')
                     if not path:
                         continue
-                    path = os.path.join(getcwd(), *path.split('/'))
+                    path = os.path.join(os.getcwd(), *path.split('/'))
                     if os.path.exists(path):
                         return path
         except Exception:
@@ -260,7 +257,7 @@ class EPUBInput(InputFormatPlugin):
         from calibre.ebooks.metadata.opf2 import OPF
         try:
             zf = ZipFile(stream)
-            zf.extractall(getcwd())
+            zf.extractall(os.getcwd())
         except:
             log.exception('EPUB appears to be invalid ZIP file, trying a'
                     ' more forgiving ZIP parser')
@@ -280,7 +277,7 @@ class EPUBInput(InputFormatPlugin):
         if opf is None:
             raise ValueError('%s is not a valid EPUB file (could not find opf)'%path)
 
-        opf = os.path.relpath(opf, getcwd())
+        opf = os.path.relpath(opf, os.getcwd())
         parts = os.path.split(opf)
         opf = OPF(opf, os.path.dirname(os.path.abspath(opf)))
 
@@ -405,7 +402,7 @@ class EPUBInput(InputFormatPlugin):
 
         with NamedTemporaryFile(suffix='.ncx', dir=os.path.dirname(nav_path), delete=False) as f:
             f.write(etree.tostring(ncx, encoding='utf-8'))
-        ncx_href = os.path.relpath(f.name, getcwd()).replace(os.sep, '/')
+        ncx_href = os.path.relpath(f.name, os.getcwd()).replace(os.sep, '/')
         ncx_id = opf.create_manifest_item(ncx_href, NCX_MIME, append=True).get('id')
         for spine in opf.root.xpath('//*[local-name()="spine"]'):
             spine.set('toc', ncx_id)

src/calibre/ebooks/conversion/plugins/epub_output.py

@@ -12,7 +12,7 @@ from calibre.customize.conversion import (OutputFormatPlugin,
         OptionRecommendation)
 from calibre.ptempfile import TemporaryDirectory
 from calibre import CurrentDir
-from polyglot.builtins import unicode_type, filter, map, zip, range, as_bytes
+from polyglot.builtins import as_bytes
 
 block_level_tags = (
       'address',
@@ -225,15 +225,15 @@ class EPUBOutput(OutputFormatPlugin):
         identifiers = oeb.metadata['identifier']
         uuid = None
         for x in identifiers:
-            if x.get(OPF('scheme'), None).lower() == 'uuid' or unicode_type(x).startswith('urn:uuid:'):
+            if x.get(OPF('scheme'), None).lower() == 'uuid' or str(x).startswith('urn:uuid:'):
-                uuid = unicode_type(x).split(':')[-1]
+                uuid = str(x).split(':')[-1]
                 break
         encrypted_fonts = getattr(input_plugin, 'encrypted_fonts', [])
 
         if uuid is None:
             self.log.warn('No UUID identifier found')
             from uuid import uuid4
-            uuid = unicode_type(uuid4())
+            uuid = str(uuid4())
             oeb.metadata.add('identifier', uuid, scheme='uuid', id=uuid)
 
         if encrypted_fonts and not uuid.startswith('urn:uuid:'):
@@ -241,7 +241,7 @@ class EPUBOutput(OutputFormatPlugin):
             # for some absurd reason, or it will throw a hissy fit and refuse
             # to use the obfuscated fonts.
             for x in identifiers:
-                if unicode_type(x) == uuid:
+                if str(x) == uuid:
                     x.content = 'urn:uuid:'+uuid
 
         with TemporaryDirectory('_epub_output') as tdir:
@@ -291,7 +291,7 @@ class EPUBOutput(OutputFormatPlugin):
         from calibre.ebooks.oeb.polish.cover import fix_conversion_titlepage_links_in_nav
         try:
             os.mkdir(os.path.join(tdir, 'META-INF'))
-        except EnvironmentError:
+        except OSError:
             pass
         with open(os.path.join(tdir, 'META-INF', 'container.xml'), 'wb') as f:
             f.write(simple_container_xml(os.path.basename(opf)).encode('utf-8'))
@@ -307,7 +307,7 @@ class EPUBOutput(OutputFormatPlugin):
         os.remove(f.name)
         try:
             os.rmdir(os.path.join(tdir, 'META-INF'))
-        except EnvironmentError:
+        except OSError:
             pass
 
     def encrypt_fonts(self, uris, tdir, uuid):  # {{{
@@ -336,7 +336,7 @@ class EPUBOutput(OutputFormatPlugin):
                         f.write(bytes(bytearray(data[i] ^ key[i%16] for i in range(1024))))
                     else:
                         self.log.warn('Font', path, 'is invalid, ignoring')
-                if not isinstance(uri, unicode_type):
+                if not isinstance(uri, str):
                     uri = uri.decode('utf-8')
                 fonts.append('''
                 <enc:EncryptedData>