Add an attribute to the main item record for caching a Metadata instance. LibraryDatabase2.get_metadata it if None, and returns it if not None.

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

@@ -114,6 +114,12 @@ class Metadata(object):
             # Don't abuse this privilege
             self.__dict__[field] = val
 
+    def deepcopy(self):
+        m = Metadata(None)
+        m.__dict__ = copy.deepcopy(self.__dict__)
+        object.__setattr__(m, '_data', copy.deepcopy(object.__getattribute__(self, '_data')))
+        return m
+
     def get(self, field, default=None):
         if default is not None:
             try:

src/calibre/library/caches.py

@@ -539,6 +539,7 @@ class ResultCache(SearchQueryParser):
                 self._data[id] = db.conn.get('SELECT * from meta2 WHERE id=?', (id,))[0]
                 self._data[id].append(db.has_cover(id, index_is_id=True))
                 self._data[id].append(db.book_on_device_string(id))
+                self._data[id].append(None)
                 if len(self.composites) > 0:
                     mi = db.get_metadata(id, index_is_id=True)
                     for k,c in self.composites:
@@ -559,6 +560,7 @@ class ResultCache(SearchQueryParser):
             self._data[id] = db.conn.get('SELECT * from meta2 WHERE id=?', (id,))[0]
             self._data[id].append(db.has_cover(id, index_is_id=True))
             self._data[id].append(db.book_on_device_string(id))
+            self._data[id].append(None)
             if len(self.composites) > 0:
                 mi = db.get_metadata(id, index_is_id=True)
                 for k,c in self.composites:
@@ -588,6 +590,7 @@ class ResultCache(SearchQueryParser):
             if item is not None:
                 item.append(db.has_cover(item[0], index_is_id=True))
                 item.append(db.book_on_device_string(item[0]))
+                item.append(None)
                 if len(self.composites) > 0:
                     mi = db.get_metadata(item[0], index_is_id=True)
                     for k,c in self.composites:

src/calibre/library/database2.py

@@ -20,8 +20,8 @@ from calibre.library.caches import ResultCache
 from calibre.library.custom_columns import CustomColumns
 from calibre.library.sqlite import connect, IntegrityError, DBThread
 from calibre.library.prefs import DBPrefs
-from calibre.ebooks.metadata import string_to_authors, authors_to_string, \
+from calibre.ebooks.metadata import string_to_authors, authors_to_string
-                                    MetaInformation
+from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.meta import get_metadata, metadata_from_formats
 from calibre.constants import preferred_encoding, iswindows, isosx, filesystem_encoding
 from calibre.ptempfile import PersistentTemporaryFile
@@ -282,6 +282,8 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
         self.field_metadata.set_field_record_index('cover', base+1, prefer_custom=False)
         self.FIELD_MAP['ondevice'] = base+2
         self.field_metadata.set_field_record_index('ondevice', base+2, prefer_custom=False)
+        self.FIELD_MAP['all_metadata'] = base+3
+        self.field_metadata.set_field_record_index('all_metadata', base+3, prefer_custom=False)
 
         script = '''
         DROP VIEW IF EXISTS meta2;
@@ -520,15 +522,26 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
 
     def get_metadata(self, idx, index_is_id=False, get_cover=False):
         '''
-        Convenience method to return metadata as a L{MetaInformation} object.
+        Convenience method to return metadata as a L{Metadata} object.
         '''
+        mi = self.data.get(idx, self.FIELD_MAP['all_metadata'],
+                           row_is_id = index_is_id)
+        if mi is not None:
+            return mi
+
+        mi = self.field_metadata.get_empty_metadata_instance()
+        self.data.set(idx, self.FIELD_MAP['all_metadata'], mi,
+                      row_is_id = index_is_id)
+
         aut_list = self.authors_with_sort_strings(idx, index_is_id=index_is_id)
         aum = []
         aus = {}
         for (author, author_sort) in aut_list:
             aum.append(author)
             aus[author] = author_sort
-        mi = MetaInformation(self.title(idx, index_is_id=index_is_id), aum)
+        mi = self.field_metadata.get_empty_metadata_instance()
+        mi.title       = self.title(idx, index_is_id=index_is_id)
+        mi.authors     = aum
         mi.author_sort = self.author_sort(idx, index_is_id=index_is_id)
         mi.author_sort_map = aus
         mi.comments    = self.comments(idx, index_is_id=index_is_id)
@@ -1056,7 +1069,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
 
     def set_metadata(self, id, mi, ignore_errors=False):
         '''
-        Set metadata for the book `id` from the `MetaInformation` object `mi`
+        Set metadata for the book `id` from the `Metadata` object `mi`
         '''
         def doit(func, *args, **kwargs):
             try:
@@ -1710,7 +1723,7 @@ class LibraryDatabase2(LibraryDatabase, SchemaUpgrade, CustomColumns):
             try:
                 mi = get_metadata(stream, format)
             except:
-                mi = MetaInformation(title, ['calibre'])
+                mi = Metadata(title, ['calibre'])
             stream.seek(0)
             mi.title, mi.authors = title, ['calibre']
             mi.tags = [_('Catalog')]

src/calibre/library/field_metadata.py

@@ -209,6 +209,15 @@ class FieldMetadata(dict):
                            'search_terms':[],
                            'is_custom':False,
                            'is_category':False}),
+            ('all_metadata',{'table':None,
+                             'column':None,
+                             'datatype':None,
+                             'is_multiple':None,
+                             'kind':'field',
+                             'name':None,
+                             'search_terms':[],
+                             'is_custom':False,
+                             'is_category':False}),
             ('ondevice',  {'table':None,
                            'column':None,
                            'datatype':'text',