Dont use a worker process when generating thumbnails, for better performance

src/calibre/srv/content.py

@@ -16,6 +16,7 @@ from functools import partial
 from calibre import fit_image
 from calibre.constants import config_dir, iswindows
 from calibre.db.errors import NoSuchFormat
+from calibre.ebooks.covers import cprefs, override_prefs, scale_cover, generate_cover, set_use_roman
 from calibre.ebooks.metadata import authors_to_string
 from calibre.ebooks.metadata.meta import set_metadata
 from calibre.ebooks.metadata.opf2 import metadata_to_opf
@@ -28,7 +29,6 @@ from calibre.utils.date import timestampfromdt
 from calibre.utils.img import scale_image, image_from_data
 from calibre.utils.filenames import ascii_filename, atomic_rename
 from calibre.utils.shared_file import share_open
-from calibre.utils.ipc.simple_worker import fork_job, WorkerError
 
 plugboard_content_server_value = 'content_server'
 plugboard_content_server_formats = ['epub', 'mobi', 'azw3']
@@ -96,14 +96,9 @@ def create_file_copy(ctx, rd, prefix, library_id, book_id, ext, mtime, copy_func
             rd.outheaders['Tempfile'] = hexlify(fname.encode('utf-8'))
         return rd.filesystem_file_with_custom_etag(ans, prefix, library_id, book_id, mtime, extra_etag_data)
 
-
-def generate_cover_worker(width, height, opf, file_name, use_roman):
-    # We have to generate the cover in a worker as it depends on Qt and needs
-    # QApplication
-    from calibre.ebooks.covers import cprefs, override_prefs, scale_cover, generate_cover, set_use_roman
-    from calibre.ebooks.metadata.opf2 import OPF
-    set_use_roman(use_roman)
-    mi = OPF(BytesIO(opf), try_to_guess_cover=False, populate_spine=False).to_book_metadata()
+def write_generated_cover(db, book_id, width, height, destf):
+    mi = db.get_metadata(book_id)
+    set_use_roman(get_use_roman())
     if height is None:
         prefs = cprefs
     else:
@@ -111,17 +106,7 @@ def generate_cover_worker(width, height, opf, file_name, use_roman):
         prefs = override_prefs(cprefs)
         scale_cover(prefs, ratio)
     cdata = generate_cover(mi, prefs=prefs)
-    with share_open(file_name, 'w+b') as f:
-        f.write(cdata)
-
-
-def write_generated_cover(db, book_id, width, height, destf):
-    from calibre.ebooks.metadata.opf2 import metadata_to_opf
-    mi = metadata_to_opf(db.get_metadata(book_id))
-    try:
-        fork_job('calibre.srv.content', 'generate_cover_worker', args=(width, height, mi, destf.name, get_use_roman()), no_output=True)
-    except WorkerError as err:
-        raise Exception(err.orig_tb)
+    destf.write(cdata)
 
 def generated_cover(ctx, rd, library_id, db, book_id, width=None, height=None):
     prefix = 'generated-cover'

src/calibre/srv/metadata.py

@@ -16,7 +16,7 @@ from calibre.constants import config_dir
 from calibre.db.categories import Tag
 from calibre.ebooks.metadata.sources.identify import urls_from_identifiers
 from calibre.utils.date import isoformat, UNDEFINED_DATE, local_tz
-from calibre.utils.config import tweaks, JSONConfig
+from calibre.utils.config import tweaks
 from calibre.utils.formatter import EvalFormatter
 from calibre.utils.file_type_icons import EXT_MAP
 from calibre.utils.icu import collation_order
@@ -154,8 +154,9 @@ def icon_map():
     global _icon_map
     with _icon_map_lock:
         if _icon_map is None:
+            from calibre.gui2 import gprefs
             _icon_map = category_icon_map.copy()
-            custom_icons = JSONConfig('gui').get('tags_browser_category_icons', {})
+            custom_icons = gprefs.get('tags_browser_category_icons', {})
             for k, v in custom_icons.iteritems():
                 if os.access(os.path.join(config_dir, 'tb_icons', v), os.R_OK):
                     _icon_map[k] = '_' + quote(v)

src/calibre/srv/standalone.py

@@ -237,4 +237,7 @@ def main(args=sys.argv):
     signal.signal(signal.SIGTERM, lambda s,f: server.stop())
     if not opts.daemonize and not iswindows:
         signal.signal(signal.SIGHUP, lambda s,f: server.stop())
+    # Needed for dynamic cover generation, which uses Qt for drawing
+    from calibre.gui2 import ensure_app, load_builtin_fonts
+    ensure_app(), load_builtin_fonts()
     server.serve_forever()

src/calibre/srv/utils.py

@@ -6,7 +6,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 __license__ = 'GPL v3'
 __copyright__ = '2015, Kovid Goyal <kovid at kovidgoyal.net>'
 
-import errno, socket, select, os, re
+import errno, socket, select, os
 from Cookie import SimpleCookie
 from contextlib import closing
 from urlparse import parse_qs
@@ -18,7 +18,7 @@ from urllib import quote as urlquote
 from binascii import hexlify, unhexlify
 
 from calibre import prints
-from calibre.constants import iswindows, config_dir
+from calibre.constants import iswindows
 from calibre.srv.errors import HTTPNotFound
 from calibre.utils.config_base import tweaks
 from calibre.utils.localization import get_translator
@@ -511,12 +511,6 @@ _use_roman = None
 def get_use_roman():
     global _use_roman
     if _use_roman is None:
-        try:
-            with lopen(os.path.join(config_dir, 'gui.py'), 'rb') as f:
-                raw = f.read()
-        except EnvironmentError:
-            _use_roman = False
-        else:
-            m = re.search(br'use_roman_numerals_for_series_number\s*=\s*(True|False)', raw)
-            _use_roman = m is not None and m.group(1) == b'True'
+        from calibre.gui2 import config
+        _use_roman = config['use_roman_numerals_for_series_number']
     return _use_roman