Make sorting on the device view faster and more robust. Fixes #742626 (Error when transferring to iTunes)

src/calibre/gui2/library/models.py

@@ -7,7 +7,6 @@ __docformat__ = 'restructuredtext en'
 
 import shutil, functools, re, os, traceback
 from contextlib import closing
-from operator import attrgetter
 
 from PyQt4.Qt import QAbstractTableModel, Qt, pyqtSignal, QIcon, QImage, \
         QModelIndex, QVariant, QDate, QColor
@@ -18,7 +17,7 @@ from calibre.ebooks.metadata import fmt_sidx, authors_to_string, string_to_autho
 from calibre.ptempfile import PersistentTemporaryFile
 from calibre.utils.config import tweaks, prefs
 from calibre.utils.date import dt_factory, qt_to_dt, isoformat
-from calibre.utils.icu import sort_key, strcmp as icu_strcmp
+from calibre.utils.icu import sort_key
 from calibre.ebooks.metadata.meta import set_metadata as _set_metadata
 from calibre.utils.search_query_parser import SearchQueryParser
 from calibre.library.caches import _match, CONTAINS_MATCH, EQUALS_MATCH, \
@@ -984,6 +983,21 @@ class OnDeviceSearch(SearchQueryParser): # {{{
 
 # }}}
 
+class DeviceDBSortKeyGen(object): # {{{
+
+    def __init__(self, attr, keyfunc, db):
+        self.attr = attr
+        self.db = db
+        self.keyfunc = keyfunc
+
+    def __call__(self, x):
+        try:
+            ans = self.keyfunc(getattr(self.db[x], self.attr))
+        except:
+            ans = None
+        return ans
+# }}}
+
 class DeviceBooksModel(BooksModel): # {{{
 
     booklist_dirtied = pyqtSignal()
@@ -1089,59 +1103,40 @@ class DeviceBooksModel(BooksModel): # {{{
 
     def sort(self, col, order, reset=True):
         descending = order != Qt.AscendingOrder
-        def strcmp(attr):
-            ag = attrgetter(attr)
-            def _strcmp(x, y):
-                x = ag(self.db[x])
-                y = ag(self.db[y])
-                if x == None:
-                    x = ''
-                if y == None:
-                    y = ''
-                return icu_strcmp(x.strip(), y.strip())
-            return _strcmp
-        def datecmp(x, y):
-            x = self.db[x].datetime
-            y = self.db[y].datetime
-            return cmp(dt_factory(x, assume_utc=True), dt_factory(y,
-                assume_utc=True))
-        def sizecmp(x, y):
-            x, y = int(self.db[x].size), int(self.db[y].size)
-            return cmp(x, y)
-        def tagscmp(x, y):
-            x = ','.join(sorted(getattr(self.db[x], 'device_collections', []),key=sort_key))
-            y = ','.join(sorted(getattr(self.db[y], 'device_collections', []),key=sort_key))
-            return cmp(x, y)
-        def libcmp(x, y):
-            x, y = self.db[x].in_library, self.db[y].in_library
-            return cmp(x, y)
-        def authorcmp(x, y):
-            ax = getattr(self.db[x], 'author_sort', None)
-            ay = getattr(self.db[y], 'author_sort', None)
-            if ax and ay:
-                x = ax
-                y = ay
-            else:
-                x, y = authors_to_string(self.db[x].authors), \
-                                authors_to_string(self.db[y].authors)
-            return cmp(x, y)
         cname = self.column_map[col]
-        fcmp = {
-                'title': strcmp('title_sorter'),
-                'authors' : authorcmp,
-                'size' : sizecmp,
-                'timestamp': datecmp,
-                'collections': tagscmp,
-                'inlibrary': libcmp,
+        def author_key(x):
+            try:
+                ax = self.db[x].author_sort
+                if not ax:
+                    raise Exception('')
+            except:
+                try:
+                    ax = authors_to_string(self.db[x].authors)
+                except:
+                    ax = ''
+            return ax
+
+        keygen = {
+                'title': ('title_sorter', lambda x: sort_key(x) if x else ''),
+                'authors' : author_key,
+                'size' : ('size', int),
+                'timestamp': ('datetime', functools.partial(dt_factory, assume_utc=True)),
+                'collections': ('device_collections', lambda x:sorted(x,
+                    key=sort_key)),
+                'inlibrary': ('in_library', lambda x: x),
                 }[cname]
-        self.map.sort(cmp=fcmp, reverse=descending)
+        keygen = keygen if callable(keygen) else DeviceDBSortKeyGen(
+            keygen[0], keygen[1], self.db)
+        self.map.sort(key=keygen, reverse=descending)
         if len(self.map) == len(self.db):
             self.sorted_map = list(self.map)
         else:
             self.sorted_map = list(range(len(self.db)))
-            self.sorted_map.sort(cmp=fcmp, reverse=descending)
+            self.sorted_map.sort(cmp=keygen, reverse=descending)
         self.sorted_on = (self.column_map[col], order)
         self.sort_history.insert(0, self.sorted_on)
+        if hasattr(keygen, 'db'):
+            keygen.db = None
         if reset:
             self.reset()