py3: port filter()

recipes/el_pais.recipe

@@ -64,7 +64,7 @@ class ElPais(BasicNewsRecipe):
     def preprocess_html(self, soup):
         for img in soup.findAll('img', srcset=True):
             try:
-                img['src'] = filter(None, img['srcset'].split())[0]
+                img['src'] = list(filter(None, img['srcset'].split()))[0]
             except IndexError:
                 continue
         return soup

recipes/hurriyet_daily_news.recipe

@@ -102,7 +102,7 @@ class HurriyetDailyNews_en(BasicNewsRecipe):
         regex = re.compile('rmRootLink', re.IGNORECASE)
         links = soup.findAll('a', {'class': regex})
 
-        filtered_links = filter(include_link, links)
+        filtered_links = list(filter(include_link, links))
         self._p(' all sections: ' + ', '.join(map(self.text, links)))
         self._p(' filtered sections: ' +
                 ', '.join(map(self.text, filtered_links)))

src/calibre/__init__.py

@@ -5,7 +5,7 @@ __docformat__ = 'restructuredtext en'
 
 import sys, os, re, time, random, warnings
 from polyglot.builtins import (builtins, codepoint_to_chr, iteritems,
-        itervalues, unicode_type, range)
+        itervalues, unicode_type, range, filter)
 builtins.__dict__['dynamic_property'] = lambda func: func(None)
 from math import floor
 from functools import partial
@@ -376,9 +376,9 @@ USER_AGENT_MOBILE = 'Mozilla/5.0 (Windows; U; Windows CE 5.1; rv:1.8.1a3) Gecko/
 def random_user_agent(choose=None, allow_ie=True):
     from calibre.utils.random_ua import common_user_agents
     ua_list = common_user_agents()
-    ua_list = filter(lambda x: 'Mobile/' not in x, ua_list)
+    ua_list = list(filter(lambda x: 'Mobile/' not in x, ua_list))
     if not allow_ie:
-        ua_list = filter(lambda x: 'Trident/' not in x and 'Edge/' not in x, ua_list)
+        ua_list = list(filter(lambda x: 'Trident/' not in x and 'Edge/' not in x, ua_list))
     return random.choice(ua_list) if choose is None else ua_list[choose]
 
 

src/calibre/db/cache.py

@@ -11,7 +11,7 @@ import os, traceback, random, shutil, operator
 from io import BytesIO
 from collections import defaultdict, Set, MutableSet
 from functools import wraps, partial
-from polyglot.builtins import iteritems, itervalues, unicode_type, zip, string_or_bytes, cmp
+from polyglot.builtins import iteritems, itervalues, unicode_type, zip, string_or_bytes, cmp, filter
 from time import time
 
 from calibre import isbytestring, as_unicode

src/calibre/db/restore.py

@@ -16,7 +16,7 @@ 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
+from polyglot.builtins import iteritems, filter
 
 NON_EBOOK_EXTENSIONS = frozenset([
         'jpg', 'jpeg', 'gif', 'png', 'bmp',
@@ -184,7 +184,7 @@ class Restore(Thread):
 
     def process_dir(self, dirpath, filenames, book_id):
         book_id = int(book_id)
-        formats = filter(self.is_ebook_file, filenames)
+        formats = list(filter(self.is_ebook_file, filenames))
         fmts    = [os.path.splitext(x)[1][1:].upper() for x in formats]
         sizes   = [os.path.getsize(os.path.join(dirpath, x)) for x in formats]
         names   = [os.path.splitext(x)[0] for x in formats]

src/calibre/db/utils.py

@@ -9,7 +9,7 @@ __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
+from polyglot.builtins import iteritems, itervalues, map, unicode_type, string_or_bytes, filter
 from threading import Lock
 
 from calibre import as_unicode, prints

src/calibre/devices/winusb.py

@@ -15,7 +15,7 @@ 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
+from polyglot.builtins import iteritems, itervalues, map, filter
 
 from calibre import prints, as_unicode
 
@@ -677,7 +677,7 @@ def get_volume_pathnames(volume_id, buf=None):
                 continue
             raise
     ans = wstring_at(buf, bufsize.value)
-    return buf, filter(None, ans.split('\0'))
+    return buf, list(filter(None, ans.split('\0')))
 
 # }}}
 
@@ -979,7 +979,7 @@ def get_device_languages(hub_handle, device_port, buf=None):
     if dtype != 0x03:
         raise WindowsError('Invalid datatype for string descriptor: 0x%x' % dtype)
     data = cast(data.String, POINTER(USHORT*(sz//2)))
-    return buf, filter(None, data.contents)
+    return buf, list(filter(None, data.contents))
 
 # }}}
 

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
+from polyglot.builtins import unicode_type, filter
 
 block_level_tags = (
       'address',
@@ -432,7 +432,7 @@ class EPUBOutput(OutputFormatPlugin):
                     br.tag = XHTML('p')
                     br.text = u'\u00a0'
                     style = br.get('style', '').split(';')
-                    style = filter(None, map(lambda x: x.strip(), style))
+                    style = list(filter(None, map(lambda x: x.strip(), style)))
                     style.append('margin:0pt; border:0pt')
                     # If the prior tag is a block (including a <br> we replaced)
                     # then this <br> replacement should have a 1-line height.

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

@@ -5,7 +5,7 @@ __copyright__ = '2008, Kovid Goyal <kovid at kovidgoyal.net>'
 import os, glob, re, textwrap
 
 from calibre.customize.conversion import InputFormatPlugin, OptionRecommendation
-from polyglot.builtins import iteritems
+from polyglot.builtins import iteritems, filter
 
 border_style_map = {
         'single' : 'solid',

src/calibre/ebooks/docx/index.py

@@ -11,7 +11,7 @@ from operator import itemgetter
 from lxml import etree
 
 from calibre.utils.icu import partition_by_first_letter, sort_key
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 
 
 def get_applicable_xe_fields(index, xe_fields, XPath, expand):
@@ -249,7 +249,7 @@ def polish_index_markup(index, blocks):
         if a:
             text = etree.tostring(a[0], method='text', with_tail=False, encoding=unicode_type).strip()
         if ':' in text:
-            path_map[block] = parts = filter(None, (x.strip() for x in text.split(':')))
+            path_map[block] = parts = list(filter(None, (x.strip() for x in text.split(':'))))
             if len(parts) > 1:
                 split_up_block(block, a[0], text, parts, ldict)
         else:

src/calibre/ebooks/docx/tables.py

@@ -10,7 +10,7 @@ from lxml.html.builder import TABLE, TR, TD
 
 from calibre.ebooks.docx.block_styles import inherit, read_shd as rs, read_border, binary_property, border_props, ParagraphStyle, border_to_css
 from calibre.ebooks.docx.char_styles import RunStyle
-from polyglot.builtins import iteritems, itervalues, range
+from polyglot.builtins import iteritems, itervalues, range, filter
 
 # Read from XML {{{
 read_shd = rs

src/calibre/ebooks/docx/to_html.py

@@ -29,7 +29,7 @@ from calibre.ebooks.docx.fields import Fields
 from calibre.ebooks.docx.settings import Settings
 from calibre.ebooks.metadata.opf2 import OPFCreator
 from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
-from polyglot.builtins import iteritems, itervalues
+from polyglot.builtins import iteritems, itervalues, filter
 
 
 NBSP = '\xa0'

src/calibre/ebooks/docx/writer/styles.py

@@ -15,7 +15,7 @@ from lxml import etree
 from calibre.ebooks import parse_css_length
 from calibre.ebooks.docx.writer.utils import convert_color, int_or_zero
 from calibre.utils.localization import lang_as_iso639_1
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 from tinycss.css21 import CSS21Parser
 
 css_parser = CSS21Parser()
@@ -702,7 +702,7 @@ class StylesManager(object):
             counts[s] += sum(1 for b in blocks if not b.is_empty())
         for i, heading_tag in enumerate(sorted(heading_styles)):
             styles = sorted((smap[k] for k in heading_styles[heading_tag]), key=counts.__getitem__)
-            styles = filter(lambda s:s.outline_level is None, styles)
+            styles = list(filter(lambda s:s.outline_level is None, styles))
             if styles:
                 heading_style = styles[-1]
                 heading_style.outline_level = i

src/calibre/ebooks/epub/periodical.py

@@ -11,7 +11,7 @@ import time
 from calibre.constants import __appname__, __version__
 from calibre import strftime, prepare_string_for_xml as xml
 from calibre.utils.date import parse_date
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, filter
 
 SONY_METADATA = u'''\
 <?xml version="1.0" encoding="utf-8"?>

src/calibre/ebooks/metadata/archive.py

@@ -10,6 +10,7 @@ import os
 from contextlib import closing
 
 from calibre.customize import FileTypePlugin
+from polyglot.builtins import filter
 
 
 def is_comic(list_of_names):

src/calibre/ebooks/metadata/author_mapper.py

@@ -8,6 +8,7 @@ import re
 from collections import deque
 
 from calibre.utils.icu import capitalize, lower, upper
+from polyglot.builtins import filter
 
 
 def cap_author_token(token):
@@ -142,7 +143,7 @@ def map_authors(authors, rules=()):
     ans = []
     for a in authors:
         ans.extend(apply_rules(a, rules))
-    return uniq(filter(None, ans))
+    return uniq(list(filter(None, ans)))
 
 
 def find_tests():

src/calibre/ebooks/metadata/book/base.py

@@ -14,7 +14,7 @@ from calibre.ebooks.metadata.book import (SC_COPYABLE_FIELDS,
         TOP_LEVEL_IDENTIFIERS, ALL_METADATA_FIELDS)
 from calibre.library.field_metadata import FieldMetadata
 from calibre.utils.icu import sort_key
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 
 # Special sets used to optimize the performance of getting and setting
 # attributes on Metadata objects

src/calibre/ebooks/metadata/book/render.py

@@ -20,7 +20,7 @@ from calibre.utils.formatter import EvalFormatter
 from calibre.utils.date import is_date_undefined
 from calibre.utils.localization import calibre_langcode_to_name
 from calibre.utils.serialize import json_dumps
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, filter
 from polyglot.binary import as_hex_unicode
 
 default_sort = ('title', 'title_sort', 'authors', 'author_sort', 'series', 'rating', 'pubdate', 'tags', 'publisher', 'identifiers')

src/calibre/ebooks/metadata/kfx.py

@@ -18,7 +18,7 @@ from calibre.utils.config_base import tweaks
 from calibre.utils.date import parse_only_date
 from calibre.utils.localization import canonicalize_lang
 from calibre.utils.imghdr import identify
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, filter
 from polyglot.binary import as_base64_bytes, from_base64_bytes
 
 

src/calibre/ebooks/metadata/opf3.py

@@ -8,7 +8,7 @@ import json
 import re
 from collections import defaultdict, namedtuple
 from functools import wraps
-from polyglot.builtins import iteritems, map
+from polyglot.builtins import iteritems, map, filter
 
 from lxml import etree
 
@@ -411,7 +411,7 @@ def set_languages(root, prefixes, refines, languages):
         val = (lang.text or '').strip()
         if val:
             opf_languages.append(val)
-    languages = filter(lambda x: x and x != 'und', normalize_languages(opf_languages, languages))
+    languages = list(filter(lambda x: x and x != 'und', normalize_languages(opf_languages, languages)))
     if not languages:
         # EPUB spec says dc:language is required
         languages = ['und']
@@ -688,7 +688,7 @@ def read_tags(root, prefixes, refines):
     for dc in XPath('./opf:metadata/dc:subject')(root):
         if dc.text:
             ans.extend(map(normalize_whitespace, dc.text.split(',')))
-    return uniq(filter(None, ans))
+    return uniq(list(filter(None, ans)))
 
 
 def set_tags(root, prefixes, refines, val):
@@ -696,7 +696,7 @@ def set_tags(root, prefixes, refines, val):
         remove_element(dc, refines)
     m = XPath('./opf:metadata')(root)[0]
     if val:
-        val = uniq(filter(None, val))
+        val = uniq(list(filter(None, val)))
         for x in val:
             c = m.makeelement(DC('subject'))
             c.text = normalize_whitespace(x)

src/calibre/ebooks/metadata/rtf.py

@@ -11,7 +11,7 @@ import re
 
 from calibre import force_unicode
 from calibre.ebooks.metadata import MetaInformation
-from polyglot.builtins import codepoint_to_chr, string_or_bytes, unicode_type, int_to_byte
+from polyglot.builtins import codepoint_to_chr, string_or_bytes, unicode_type, int_to_byte, filter
 
 title_pat    = re.compile(br'\{\\info.*?\{\\title(.*?)(?<!\\)\}', re.DOTALL)
 author_pat   = re.compile(br'\{\\info.*?\{\\author(.*?)(?<!\\)\}', re.DOTALL)

src/calibre/ebooks/metadata/tag_mapper.py

@@ -5,6 +5,7 @@
 from __future__ import (unicode_literals, division, absolute_import,
                         print_function)
 from collections import deque
+from polyglot.builtins import filter
 
 
 def compile_pat(pat):
@@ -88,7 +89,7 @@ def apply_rules(tag, rules):
                     ans.append(icu_upper(tag))
                     break
                 if ac == 'split':
-                    stags = filter(None, [x.strip() for x in tag.split(rule['replace'])])
+                    stags = list(filter(None, (x.strip() for x in tag.split(rule['replace']))))
                     if stags:
                         if stags[0] == tag:
                             ans.append(tag)
@@ -121,7 +122,7 @@ def map_tags(tags, rules=()):
     ans = []
     for t in tags:
         ans.extend(apply_rules(t, rules))
-    return uniq(filter(None, ans))
+    return uniq(list(filter(None, ans)))
 
 
 def find_tests():
@@ -167,6 +168,7 @@ def find_tests():
             run(rule('split', 'a b', ' ', 'has'), 'a b', 'a,b')
     return unittest.defaultTestLoader.loadTestsFromTestCase(TestTagMapper)
 
+
 if __name__ == '__main__':
     from calibre.utils.run_tests import run_cli
     run_cli(find_tests())

src/calibre/ebooks/metadata/utils.py

@@ -14,6 +14,7 @@ from calibre.ebooks.oeb.base import OPF
 from calibre.ebooks.oeb.polish.utils import guess_type
 from calibre.spell import parse_lang_code
 from calibre.utils.localization import lang_as_iso639_1
+from polyglot.builtins import filter
 
 PARSER = etree.XMLParser(recover=True, no_network=True)
 

src/calibre/ebooks/metadata/xmp.py

@@ -19,7 +19,7 @@ from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import dump_dict
 from calibre.utils.date import parse_date, isoformat, now
 from calibre.utils.localization import canonicalize_lang, lang_as_iso639_1
-from polyglot.builtins import iteritems, string_or_bytes
+from polyglot.builtins import iteritems, string_or_bytes, filter
 
 _xml_declaration = re.compile(r'<\?xml[^<>]+encoding\s*=\s*[\'"](.*?)[\'"][^<>]*>', re.IGNORECASE)
 

src/calibre/ebooks/mobi/debug/containers.py

@@ -9,6 +9,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from struct import unpack_from
 
 from calibre.ebooks.mobi.debug.headers import EXTHHeader
+from polyglot.builtins import filter
 
 
 class ContainerHeader(object):
@@ -43,7 +44,7 @@ class ContainerHeader(object):
 
     def add_hrefs(self, data):
         # kindlegen inserts a trailing | after the last href
-        self.hrefs = filter(None, data.decode('utf-8').split('|'))
+        self.hrefs = list(filter(None, data.decode('utf-8').split('|')))
 
     def __str__(self):
         ans = [('*'*10) + ' Container Header ' + ('*'*10)]
@@ -64,4 +65,3 @@ class ContainerHeader(object):
         if len(self.bytes_after_exth) != self.null_bytes_after_exth:
             a('Non-null bytes present after EXTH header!!!!')
         return '\n'.join(ans) + '\n\n' + str(self.exth) + '\n\n' + ('Title: %s' % self.title)
-

src/calibre/ebooks/odt/input.py

@@ -19,7 +19,7 @@ from odf.namespaces import TEXTNS as odTEXTNS
 
 from calibre import CurrentDir, walk
 from calibre.ebooks.oeb.base import _css_logger
-from polyglot.builtins import unicode_type, string_or_bytes
+from polyglot.builtins import unicode_type, string_or_bytes, filter
 
 
 class Extract(ODF2XHTML):
@@ -129,8 +129,8 @@ class Extract(ODF2XHTML):
             if (len(div1), len(div2)) != (1, 1):
                 continue
             cls = div1.get('class', '')
-            first_rules = filter(None, [self.get_css_for_class(x) for x in
+            first_rules = list(filter(None, [self.get_css_for_class(x) for x in
-                cls.split()])
+                cls.split()]))
             has_align = False
             for r in first_rules:
                 if r.style.getProperty(u'text-align') is not None:
@@ -139,8 +139,8 @@ class Extract(ODF2XHTML):
             if not has_align:
                 aval = None
                 cls = div2.get(u'class', u'')
-                rules = filter(None, [self.get_css_for_class(x) for x in
+                rules = list(filter(None, [self.get_css_for_class(x) for x in
-                    cls.split()])
+                    cls.split()]))
                 for r in rules:
                     ml = r.style.getPropertyCSSValue(u'margin-left') or ml
                     mr = r.style.getPropertyCSSValue(u'margin-right') or mr

src/calibre/ebooks/oeb/base.py

@@ -22,7 +22,7 @@ from calibre.ebooks.oeb.parse_utils import (barename, XHTML_NS, RECOVER_PARSER,
         namespace, XHTML, parse_html, NotHTML)
 from calibre.utils.cleantext import clean_xml_chars
 from calibre.utils.short_uuid import uuid4
-from polyglot.builtins import iteritems, unicode_type, string_or_bytes, range, itervalues
+from polyglot.builtins import iteritems, unicode_type, string_or_bytes, range, itervalues, filter
 from polyglot.urllib import unquote, urldefrag, urljoin, urlparse, urlunparse
 from calibre.utils.icu import numeric_sort_key
 
@@ -2008,7 +2008,7 @@ def rel_href(base_href, href):
         return href
     if '/' not in base_href:
         return href
-    base = filter(lambda x: x and x != '.', os.path.dirname(os.path.normpath(base_href)).replace(os.sep, '/').split('/'))
+    base = list(filter(lambda x: x and x != '.', os.path.dirname(os.path.normpath(base_href)).replace(os.sep, '/').split('/')))
     while True:
         try:
             idx = base.index('..')

src/calibre/ebooks/oeb/polish/css.py

@@ -18,7 +18,7 @@ from calibre.ebooks.oeb.normalize_css import normalize_filter_css, normalizers
 from calibre.ebooks.oeb.polish.pretty import pretty_script_or_style, pretty_xml_tree, serialize
 from calibre.utils.icu import numeric_sort_key
 from css_selectors import Select, SelectorError
-from polyglot.builtins import iteritems, itervalues, unicode_type
+from polyglot.builtins import iteritems, itervalues, unicode_type, filter
 
 
 def filter_used_rules(rules, log, select):
@@ -325,8 +325,7 @@ def remove_property_value(prop, predicate):
     values of the property would be removed, the property is removed from its
     parent instead. Note that this means the property must have a parent (a
     CSSStyleDeclaration). '''
-    removed_vals = []
+    removed_vals = list(filter(predicate, prop.propertyValue))
-    removed_vals = filter(predicate, prop.propertyValue)
     if len(removed_vals) == len(prop.propertyValue):
         prop.parent.removeProperty(prop.name)
     else:

src/calibre/ebooks/oeb/polish/fonts.py

@@ -9,7 +9,7 @@ __copyright__ = '2014, Kovid Goyal <kovid at kovidgoyal.net>'
 from calibre.ebooks.oeb.polish.container import OEB_STYLES, OEB_DOCS
 from calibre.ebooks.oeb.normalize_css import normalize_font
 from tinycss.fonts3 import parse_font_family, parse_font, serialize_font_family, serialize_font
-from polyglot.builtins import iteritems
+from polyglot.builtins import iteritems, filter
 
 
 def unquote(x):
@@ -68,7 +68,7 @@ def change_font_in_declaration(style, old_name, new_name=None):
     ff = style.getProperty('font-family')
     if ff is not None:
         fams = parse_font_family(ff.propertyValue.cssText)
-        nfams = filter(None, [new_name if x == old_name else x for x in fams])
+        nfams = list(filter(None, [new_name if x == old_name else x for x in fams]))
         if fams != nfams:
             if nfams:
                 ff.propertyValue.cssText = serialize_font_family(nfams)
@@ -79,7 +79,7 @@ def change_font_in_declaration(style, old_name, new_name=None):
     if ff is not None:
         props = parse_font(ff.propertyValue.cssText)
         fams = props.get('font-family') or []
-        nfams = filter(None, [new_name if x == old_name else x for x in fams])
+        nfams = list(filter(None, [new_name if x == old_name else x for x in fams]))
         if fams != nfams:
             props['font-family'] = nfams
             if nfams:

src/calibre/ebooks/oeb/polish/spell.py

@@ -17,7 +17,7 @@ from calibre.ebooks.oeb.polish.container import OPF_NAMESPACES, get_container
 from calibre.ebooks.oeb.polish.parsing import parse
 from calibre.ebooks.oeb.polish.toc import find_existing_ncx_toc, find_existing_nav_toc
 from calibre.utils.icu import ord_string
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 
 _patterns = None
 
@@ -86,7 +86,7 @@ def get_words(text, lang):
         ans = split_into_words(unicode_type(text), lang)
     except (TypeError, ValueError):
         return ()
-    return filter(filter_words, ans)
+    return list(filter(filter_words, ans))
 
 
 def add_words(text, node, words, file_name, locale, node_item):

src/calibre/ebooks/oeb/stylizer.py

@@ -20,7 +20,7 @@ from calibre.ebooks import unit_convert
 from calibre.ebooks.oeb.base import XHTML, XHTML_NS, CSS_MIME, OEB_STYLES, xpath, urlnormalize
 from calibre.ebooks.oeb.normalize_css import DEFAULTS, normalizers
 from css_selectors import Select, SelectorError, INAPPROPRIATE_PSEUDO_CLASSES
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 from tinycss.media3 import CSSMedia3Parser
 
 css_parser_log.setLevel(logging.WARN)

src/calibre/ebooks/rtf2xml/tokenize.py

@@ -15,7 +15,7 @@ import os, re
 from calibre.ebooks.rtf2xml import copy
 from calibre.utils.mreplace import MReplace
 from calibre.ptempfile import better_mktemp
-from polyglot.builtins import codepoint_to_chr, range
+from polyglot.builtins import codepoint_to_chr, range, filter
 
 
 class Tokenize:
@@ -124,7 +124,7 @@ class Tokenize:
         # split
         tokens = re.split(self.__splitexp, input_file)
         # remove empty tokens and \n
-        return filter(lambda x: len(x) > 0 and x != '\n', tokens)
+        return list(filter(lambda x: len(x) > 0 and x != '\n', tokens))
 
     def __compile_expressions(self):
         SIMPLE_RPL = {
@@ -184,7 +184,7 @@ class Tokenize:
         # correct unicode
         tokens = map(self.__unicode_process, tokens)
         # remove empty items created by removing \uc
-        tokens = filter(lambda x: len(x) > 0, tokens)
+        tokens = list(filter(lambda x: len(x) > 0, tokens))
 
         # write
         with open(self.__write_to, 'wb') as write_obj:

src/calibre/gui2/dialogs/add_from_isbn.py

@@ -15,7 +15,7 @@ from PyQt5.Qt import (
 from calibre.ebooks.metadata import check_isbn
 from calibre.constants import iswindows
 from calibre.gui2 import gprefs, question_dialog, error_dialog
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, filter
 
 
 class AddFromISBN(QDialog):

src/calibre/gui2/dialogs/metadata_bulk.py

@@ -32,7 +32,7 @@ from calibre.utils.date import qt_to_dt, internal_iso_format_string
 from calibre.utils.icu import capitalize, sort_key
 from calibre.utils.titlecase import titlecase
 from calibre.gui2.widgets import LineEditECM
-from polyglot.builtins import iteritems, itervalues, unicode_type, error_message
+from polyglot.builtins import iteritems, itervalues, unicode_type, error_message, filter
 
 Settings = namedtuple('Settings',
     'remove_all remove add au aus do_aus rating pub do_series do_autonumber '
@@ -186,7 +186,7 @@ class MyBlockingBusy(QDialog):  # {{{
             self.progress_next_step_range.emit(len(self.ids))
             for book_id in self.ids:
                 fmts = db.formats(book_id, verify_formats=False)
-                paths = filter(None, [db.format_abspath(book_id, fmt) for fmt in fmts])
+                paths = list(filter(None, [db.format_abspath(book_id, fmt) for fmt in fmts]))
                 if paths:
                     ret = worker(
                         'calibre.ebooks.metadata.worker', 'read_metadata_bulk',

src/calibre/gui2/dialogs/plugin_updater.py

@@ -24,7 +24,7 @@ from calibre.gui2 import error_dialog, question_dialog, info_dialog, open_url, g
 from calibre.gui2.preferences.plugins import ConfigWidget
 from calibre.utils.date import UNDEFINED_DATE, format_date
 from calibre.utils.https import get_https_resource_securely
-from polyglot.builtins import itervalues, unicode_type
+from polyglot.builtins import itervalues, unicode_type, filter
 
 SERVER = 'https://code.calibre-ebook.com/plugins/'
 INDEX_URL = '%splugins.json.bz2' % SERVER

src/calibre/gui2/icon_theme.py

@@ -35,7 +35,7 @@ from calibre.utils.img import image_from_data, Canvas, optimize_png, optimize_jp
 from calibre.utils.zipfile import ZipFile, ZIP_STORED
 from calibre.utils.filenames import atomic_rename
 from lzma.xz import compress, decompress
-from polyglot.builtins import iteritems, map, range, reraise
+from polyglot.builtins import iteritems, map, range, reraise, filter
 from polyglot import http_client
 from polyglot.queue import Queue, Empty
 

src/calibre/gui2/metadata/single.py

@@ -31,7 +31,7 @@ from calibre.ebooks.metadata.book.base import Metadata
 from calibre.utils.localization import canonicalize_lang
 from calibre.utils.date import local_tz
 from calibre.library.comments import merge_comments as merge_two_comments
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 
 BASE_TITLE = _('Edit Metadata')
 fetched_fields = ('title', 'title_sort', 'authors', 'author_sort', 'series',

src/calibre/gui2/tag_mapper.py

@@ -20,7 +20,7 @@ from calibre.gui2.ui import get_gui
 from calibre.gui2.widgets2 import Dialog
 from calibre.utils.config import JSONConfig
 from calibre.utils.localization import localize_user_manual_link
-from polyglot.builtins import iteritems, unicode_type, range
+from polyglot.builtins import iteritems, unicode_type, range, filter
 
 tag_maps = JSONConfig('tag-map-rules')
 
@@ -154,7 +154,7 @@ class RuleEdit(QWidget):
 
     def edit_tags(self):
         from calibre.gui2.dialogs.tag_editor import TagEditor
-        d = TagEditor(self, get_gui().current_db, current_tags=filter(None, [x.strip() for x in self.query.text().split(',')]))
+        d = TagEditor(self, get_gui().current_db, current_tags=list(filter(None, [x.strip() for x in self.query.text().split(',')])))
         if d.exec_() == d.Accepted:
             self.query.setText(', '.join(d.tags))
 

src/calibre/gui2/tweak_book/file_list.py

@@ -38,7 +38,7 @@ from calibre.gui2.tweak_book import (
 from calibre.gui2.tweak_book.editor import syntax_from_mime
 from calibre.gui2.tweak_book.templates import template_for
 from calibre.utils.icu import numeric_sort_key
-from polyglot.builtins import iteritems, itervalues, unicode_type, range
+from polyglot.builtins import iteritems, itervalues, unicode_type, range, filter
 from polyglot.binary import as_hex_unicode
 
 try:

src/calibre/gui2/tweak_book/preview.py

@@ -8,7 +8,7 @@ __copyright__ = '2013, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time, textwrap, json
 from bisect import bisect_right
-from polyglot.builtins import map, unicode_type
+from polyglot.builtins import map, unicode_type, filter
 from threading import Thread
 from functools import partial
 
@@ -321,7 +321,7 @@ class WebPage(QWebPage):
                     ans = None
                 return ans
             val = self.mainFrame().evaluateJavaScript('window.calibre_preview_integration.line_numbers()')
-            self._line_numbers = sorted(uniq(filter(lambda x:x is not None, map(atoi, val))))
+            self._line_numbers = sorted(uniq(list(filter(lambda x:x is not None, map(atoi, val)))))
         return self._line_numbers
 
     def go_to_line(self, lnum):

src/calibre/gui2/tweak_book/reports.py

@@ -8,7 +8,7 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import time, textwrap, os
 from threading import Thread
-from polyglot.builtins import iteritems, map, range
+from polyglot.builtins import iteritems, map, range, filter
 from operator import itemgetter
 from functools import partial
 from collections import defaultdict
@@ -166,7 +166,7 @@ class FilesView(QTableView):
 
     @property
     def selected_locations(self):
-        return filter(None, (self.proxy.sourceModel().location(self.proxy.mapToSource(index)) for index in self.selectionModel().selectedIndexes()))
+        return list(filter(None, (self.proxy.sourceModel().location(self.proxy.mapToSource(index)) for index in self.selectionModel().selectedIndexes())))
 
     @property
     def current_location(self):

src/calibre/gui2/tweak_book/search.py

@@ -34,7 +34,7 @@ from calibre.gui2.tweak_book.widgets import BusyCursor
 from calibre.gui2.widgets2 import FlowLayout, HistoryComboBox
 from calibre.utils.icu import primary_contains
 from calibre.ebooks.conversion.search_replace import REGEX_FLAGS, compile_regular_expression
-from polyglot.builtins import iteritems, unicode_type, range, error_message
+from polyglot.builtins import iteritems, unicode_type, range, error_message, filter
 
 
 # The search panel {{{

src/calibre/gui2/tweak_book/spell.py

@@ -37,7 +37,7 @@ from calibre.spell.import_from import import_from_oxt
 from calibre.spell.break_iterator import split_into_words
 from calibre.utils.localization import calibre_langcode_to_name, get_language, get_lang, canonicalize_lang
 from calibre.utils.icu import sort_key, primary_sort_key, primary_contains, contains
-from polyglot.builtins import iteritems, unicode_type, range
+from polyglot.builtins import iteritems, unicode_type, range, filter
 
 LANG = 0
 COUNTRY = 1
@@ -720,7 +720,7 @@ class WordsModel(QAbstractTableModel):
         return True
 
     def do_filter(self):
-        self.items = filter(self.filter_item, self.words)
+        self.items = list(filter(self.filter_item, self.words))
 
     def toggle_ignored(self, row):
         w = self.word_for_row(row)

src/calibre/gui2/win_file_dialogs.py

@@ -9,7 +9,7 @@ from threading import Thread
 from uuid import uuid4
 
 from PyQt5.Qt import pyqtSignal, QEventLoop, Qt
-from polyglot.builtins import string_or_bytes
+from polyglot.builtins import string_or_bytes, filter
 
 is64bit = sys.maxsize > (1 << 32)
 base = sys.extensions_location if hasattr(sys, 'new_app_layout') else os.path.dirname(sys.executable)
@@ -359,7 +359,7 @@ def test(helper=HELPER):
     if server.err_msg is not None:
         raise RuntimeError(server.err_msg)
     server.join(2)
-    parts = filter(None, server.data.split(b'\0'))
+    parts = list(filter(None, server.data.split(b'\0')))
     if parts[0] != secret:
         raise RuntimeError('Did not get back secret: %r != %r' % (secret, parts[0]))
     q = parts[1].decode('utf-8')

src/calibre/library/catalogs/bibtex.py

@@ -14,7 +14,7 @@ from calibre.library.catalogs import FIELDS, TEMPLATE_ALLOWED_FIELDS
 from calibre.customize.conversion import DummyReporter
 from calibre.constants import preferred_encoding
 from calibre.ebooks.metadata import format_isbn
-from polyglot.builtins import string_or_bytes
+from polyglot.builtins import string_or_bytes, filter
 
 
 class BIBTEX(CatalogPlugin):
@@ -384,7 +384,7 @@ class BIBTEX(CatalogPlugin):
 
             # check in book strict if all is ok else throw a warning into log
             if bib_entry == 'book' :
-                nb_books = len(filter(check_entry_book_valid, data))
+                nb_books = len(list(filter(check_entry_book_valid, data)))
                 if nb_books < nb_entries :
                     log.warn("Only %d entries in %d are book compatible" % (nb_books, nb_entries))
                     nb_entries = nb_books

src/calibre/library/check_library.py

@@ -10,7 +10,7 @@ import re, os, traceback, fnmatch
 from calibre import isbytestring
 from calibre.constants import filesystem_encoding
 from calibre.ebooks import BOOK_EXTENSIONS
-from polyglot.builtins import iteritems
+from polyglot.builtins import iteritems, filter
 
 EBOOK_EXTENSIONS = frozenset(BOOK_EXTENSIONS)
 NORMALS = frozenset(['metadata.opf', 'cover.jpg'])

src/calibre/library/database.py

@@ -12,7 +12,7 @@ from calibre.ebooks.metadata import MetaInformation
 from calibre.ebooks.metadata import string_to_authors
 from calibre.utils.serialize import pickle_loads, pickle_dumps
 from calibre import isbytestring
-from polyglot.builtins import unicode_type
+from polyglot.builtins import unicode_type, filter
 
 
 class Concatenate(object):
@@ -1070,8 +1070,8 @@ ALTER TABLE books ADD COLUMN isbn TEXT DEFAULT "" COLLATE NOCASE;
                 self.conn.get('SELECT id, name FROM authors')]
 
     def all_author_names(self):
-        return filter(None, [i[0].strip().replace('|', ',') for i in self.conn.get(
+        return list(filter(None, [i[0].strip().replace('|', ',') for i in self.conn.get(
-            'SELECT name FROM authors')])
+            'SELECT name FROM authors')]))
 
     def all_publishers(self):
         return [(i[0], i[1]) for i in

src/calibre/library/restore.py

@@ -16,7 +16,7 @@ from calibre.library.prefs import DBPrefs
 from calibre.constants import filesystem_encoding
 from calibre.utils.date import utcfromtimestamp
 from calibre import isbytestring
-from polyglot.builtins import iteritems
+from polyglot.builtins import iteritems, filter
 
 NON_EBOOK_EXTENSIONS = frozenset([
         'jpg', 'jpeg', 'gif', 'png', 'bmp',
@@ -174,7 +174,7 @@ class Restore(Thread):
 
     def process_dir(self, dirpath, filenames, book_id):
         book_id = int(book_id)
-        formats = filter(self.is_ebook_file, filenames)
+        formats = list(filter(self.is_ebook_file, filenames))
         fmts    = [os.path.splitext(x)[1][1:].upper() for x in formats]
         sizes   = [os.path.getsize(os.path.join(dirpath, x)) for x in formats]
         names   = [os.path.splitext(x)[0] for x in formats]

src/calibre/spell/dictionary.py

@@ -18,7 +18,7 @@ from calibre.spell import parse_lang_code
 from calibre.utils.config import JSONConfig
 from calibre.utils.icu import capitalize
 from calibre.utils.localization import get_lang, get_system_locale
-from polyglot.builtins import iteritems, itervalues, unicode_type
+from polyglot.builtins import iteritems, itervalues, unicode_type, filter
 
 Dictionary = namedtuple('Dictionary', 'primary_locale locales dicpath affpath builtin name id')
 LoadedDictionary = namedtuple('Dictionary', 'primary_locale locales obj builtin name id')

src/calibre/srv/handler.py

@@ -15,7 +15,7 @@ from calibre.srv.routes import Router
 from calibre.srv.users import UserManager
 from calibre.utils.date import utcnow
 from calibre.utils.search_query_parser import ParseException
-from polyglot.builtins import itervalues
+from polyglot.builtins import itervalues, filter
 
 
 class Context(object):

src/calibre/srv/http_request.py

@@ -16,7 +16,7 @@ from calibre.srv.loop import Connection, READ, WRITE
 from calibre.srv.utils import MultiDict, HTTP1, HTTP11, Accumulator
 from polyglot import http_client, reprlib
 from polyglot.urllib import unquote
-from polyglot.builtins import error_message
+from polyglot.builtins import error_message, filter
 
 protocol_map = {(1, 0):HTTP1, (1, 1):HTTP11}
 quoted_slash = re.compile(br'%2[fF]')

src/calibre/srv/legacy.py

@@ -19,7 +19,7 @@ from calibre.srv.routes import endpoint
 from calibre.srv.utils import get_library_data, http_date
 from calibre.utils.cleantext import clean_xml_chars
 from calibre.utils.date import dt_as_local, is_date_undefined, timestampfromdt
-from polyglot.builtins import iteritems, string_or_bytes
+from polyglot.builtins import iteritems, string_or_bytes, filter
 from polyglot.urllib import urlencode
 
 # /mobile {{{

src/calibre/srv/manage_users_cli.py

@@ -9,7 +9,7 @@ from functools import partial
 
 from calibre import prints
 from calibre.constants import preferred_encoding
-from polyglot.builtins import iteritems, raw_input
+from polyglot.builtins import iteritems, raw_input, filter
 
 # Manage users CLI {{{
 
@@ -175,7 +175,7 @@ def manage_users_cli(path=None):
             pass
         else:
             names = get_input(_('Enter a comma separated list of library names:'))
-            names = filter(None, [x.strip() for x in names.split(',')])
+            names = list(filter(None, [x.strip() for x in names.split(',')]))
             w = 'allowed_library_names' if c == 1 else 'blocked_library_names'
             t = _('Allowing access only to libraries: {}') if c == 1 else _(
                 'Allowing access to all libraries, except: {}')

src/calibre/srv/metadata.py

@@ -22,7 +22,7 @@ from calibre.utils.icu import collation_order
 from calibre.utils.localization import calibre_langcode_to_name
 from calibre.library.comments import comments_to_html, markdown
 from calibre.library.field_metadata import category_icon_map
-from polyglot.builtins import iteritems, itervalues, range
+from polyglot.builtins import iteritems, itervalues, range, filter
 from polyglot.urllib import quote
 
 IGNORED_FIELDS = frozenset('cover ondevice path marked au_map size'.split())
@@ -304,7 +304,7 @@ categories_with_ratings = {'authors', 'series', 'publisher', 'tags'}
 
 
 def get_name_components(name):
-    components = filter(None, [t.strip() for t in name.split('.')])
+    components = list(filter(None, [t.strip() for t in name.split('.')]))
     if not components or '.'.join(components) != name:
         components = [name]
     return components
@@ -533,9 +533,9 @@ def render_categories(opts, db, category_data):
     if opts.hidden_categories:
         # We have to remove hidden categories after all processing is done as
         # items from a hidden category could be in a user category
-        root['children'] = filter((lambda child:items[child['id']]['category'] not in opts.hidden_categories), root['children'])
+        root['children'] = list(filter((lambda child:items[child['id']]['category'] not in opts.hidden_categories), root['children']))
     if opts.hide_empty_categories:
-        root['children'] = filter((lambda child:items[child['id']]['count'] > 0), root['children'])
+        root['children'] = list(filter((lambda child:items[child['id']]['count'] > 0), root['children']))
     return {'root':root, 'item_map': items}
 
 

src/calibre/srv/opds.py

@@ -26,7 +26,7 @@ from calibre import force_unicode
 from calibre.srv.errors import HTTPNotFound, HTTPInternalServerError
 from calibre.srv.routes import endpoint
 from calibre.srv.utils import get_library_data, http_date, Offsets
-from polyglot.builtins import iteritems, unicode_type
+from polyglot.builtins import iteritems, unicode_type, filter
 from polyglot.urllib import urlencode
 from polyglot.binary import as_hex_unicode, from_hex_unicode
 

src/calibre/srv/routes.py

@@ -12,7 +12,7 @@ from operator import attrgetter
 from calibre.srv.errors import HTTPSimpleResponse, HTTPNotFound, RouteError
 from calibre.srv.utils import http_date
 from calibre.utils.serialize import msgpack_dumps, json_dumps, MSGPACK_MIME
-from polyglot.builtins import iteritems, itervalues, unicode_type, range, zip
+from polyglot.builtins import iteritems, itervalues, unicode_type, range, zip, filter
 from polyglot import http_client
 from polyglot.urllib import quote as urlquote
 
@@ -114,7 +114,7 @@ class Route(object):
         del endpoint_
         if not self.endpoint.route.startswith('/'):
             raise RouteError('A route must start with /, %s does not' % self.endpoint.route)
-        parts = filter(None, self.endpoint.route.split('/'))
+        parts = list(filter(None, self.endpoint.route.split('/')))
         matchers = self.matchers = []
         self.defaults = {}
         found_optional_part = False

src/calibre/srv/tests/routes.py

@@ -8,7 +8,7 @@ __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
 import os
 from calibre.srv.tests.base import BaseTest
-from polyglot.builtins import itervalues
+from polyglot.builtins import itervalues, filter
 
 
 class TestRouter(BaseTest):
@@ -53,7 +53,7 @@ class TestRouter(BaseTest):
         router = Router()
 
         def find(path):
-            path = filter(None, path.split('/'))
+            path = list(filter(None, path.split('/')))
             ep, args = router.find_route(path)
             args = list(args)
             return ep, args

src/calibre/utils/cleantext.py

@@ -3,7 +3,7 @@ __copyright__ = '2010, sengian <sengian1@gmail.com>'
 __docformat__ = 'restructuredtext en'
 
 import re
-from polyglot.builtins import codepoint_to_chr, map, range
+from polyglot.builtins import codepoint_to_chr, map, range, filter
 from polyglot.html_entities import name2codepoint
 from calibre.constants import plugins, preferred_encoding
 

src/calibre/utils/fonts/scanner.py

@@ -16,7 +16,7 @@ from calibre.constants import (config_dir, iswindows, isosx, plugins, DEBUG,
         isworker, filesystem_encoding)
 from calibre.utils.fonts.metadata import FontMetadata, UnsupportedFont
 from calibre.utils.icu import sort_key
-from polyglot.builtins import itervalues, unicode_type
+from polyglot.builtins import itervalues, unicode_type, filter
 
 
 class NoFonts(ValueError):
@@ -281,7 +281,7 @@ class FontScanner(Thread):
             return False
 
         for family in self.find_font_families():
-            faces = filter(filter_faces, self.fonts_for_family(family))
+            faces = list(filter(filter_faces, self.fonts_for_family(family)))
             if not faces:
                 continue
             generic_family = panose_to_css_generic_family(faces[0]['panose'])

src/calibre/utils/icu.py

@@ -8,6 +8,7 @@ __copyright__ = '2010, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
 import sys
+from polyglot.builtins import filter
 
 is_narrow_build = sys.maxunicode < 0x10ffff
 

src/calibre/utils/matcher.py

@@ -16,7 +16,7 @@ from itertools import islice
 from calibre import detect_ncpus as cpu_count, as_unicode
 from calibre.constants import plugins, filesystem_encoding
 from calibre.utils.icu import primary_sort_key, primary_find, primary_collator
-from polyglot.builtins import iteritems, itervalues, map, unicode_type, range, zip, raw_input
+from polyglot.builtins import iteritems, itervalues, map, unicode_type, range, zip, raw_input, filter
 from polyglot.queue import Queue
 
 DEFAULT_LEVEL1 = '/'

src/calibre/utils/open_with/windows.py

@@ -16,6 +16,7 @@ import win32con, win32api, win32gui, pywintypes, winerror
 from calibre import prints
 from calibre.gui2 import must_use_qt
 from calibre.utils.winreg.default_programs import split_commandline
+from polyglot.builtins import filter
 
 ICON_SIZE = 64
 

src/calibre/utils/rapydscript.py

@@ -22,7 +22,7 @@ from calibre.utils.filenames import atomic_rename
 from calibre.utils.terminal import ANSIStream
 from duktape import Context, JSError, to_python
 from lzma.xz import compress, decompress
-from polyglot.builtins import itervalues, range, exec_path, raw_input, error_message
+from polyglot.builtins import itervalues, range, exec_path, raw_input, error_message, filter
 from polyglot.queue import Empty, Queue
 
 COMPILER_PATH = 'rapydscript/compiler.js.xz'
@@ -395,8 +395,8 @@ class Repl(Thread):
         def completer(text, num):
             if self.completions is None:
                 self.to_repl.put(('complete', text))
-                self.completions = filter(None, self.get_from_repl())
+                self.completions = list(filter(None, self.get_from_repl()))
-                if self.completions is None:
+                if not self.completions:
                     return None
             try:
                 return self.completions[num]