From 4ae7a3b8c9c1b69695148675dfd47ceedc927c8a Mon Sep 17 00:00:00 2001
From: Charles Haley <>
Date: Mon, 4 Oct 2010 11:51:27 +0100
Subject: [PATCH] Make Metadata smart update handle classifiers correctly

---
 src/calibre/ebooks/metadata/book/__init__.py |  6 ++---
 src/calibre/ebooks/metadata/book/base.py     | 24 ++++++++++++++++++++
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/calibre/ebooks/metadata/book/__init__.py b/src/calibre/ebooks/metadata/book/__init__.py
index 761a573b69..2da0d1b8fb 100644
--- a/src/calibre/ebooks/metadata/book/__init__.py
+++ b/src/calibre/ebooks/metadata/book/__init__.py
@@ -104,7 +104,8 @@ STANDARD_METADATA_FIELDS = SOCIAL_METADATA_FIELDS.union(
 
 SC_FIELDS_NOT_COPIED =     frozenset(['title', 'title_sort', 'authors',
                                       'author_sort', 'author_sort_map',
-                                      'cover_data', 'tags', 'language'])
+                                      'cover_data', 'tags', 'language',
+                                      'classifiers'])
 
 # Metadata fields that smart update should copy only if the source is not None
 SC_FIELDS_COPY_NOT_NULL =  frozenset(['lpath', 'size', 'comments', 'thumbnail'])
@@ -114,8 +115,7 @@ SC_COPYABLE_FIELDS =       SOCIAL_METADATA_FIELDS.union(
                            PUBLICATION_METADATA_FIELDS).union(
                            BOOK_STRUCTURE_FIELDS).union(
                            DEVICE_METADATA_FIELDS).union(
-                           CALIBRE_METADATA_FIELDS).union(
-                           TOP_LEVEL_CLASSIFIERS) - \
+                           CALIBRE_METADATA_FIELDS) - \
                            SC_FIELDS_NOT_COPIED.union(
                            SC_FIELDS_COPY_NOT_NULL)
 
diff --git a/src/calibre/ebooks/metadata/book/base.py b/src/calibre/ebooks/metadata/book/base.py
index 8e4385100a..29a285918f 100644
--- a/src/calibre/ebooks/metadata/book/base.py
+++ b/src/calibre/ebooks/metadata/book/base.py
@@ -164,6 +164,18 @@ class Metadata(object):
     def set(self, field, val, extra=None):
         self.__setattr__(field, val, extra)
 
+    def get_classifiers(self):
+        '''
+        Return a copy of the classifiers dictionary.
+        The dict is small, and the penalty for using a reference where a copy is
+        needed is large. Also, we don't want any manipulations of the returned
+        dict to show up in the book.
+        '''
+        return copy.deepcopy(object.__getattribute__(self, '_data')['classifiers'])
+
+    def set_classifiers(self, classifiers):
+        object.__getattribute__(self, '_data')['classifiers'] = classifiers
+
     # field-oriented interface. Intended to be the same as in LibraryDatabase
 
     def standard_field_keys(self):
@@ -369,6 +381,7 @@ class Metadata(object):
             self.set_all_user_metadata(other.get_all_user_metadata(make_copy=True))
             for x in SC_FIELDS_COPY_NOT_NULL:
                 copy_not_none(self, other, x)
+            self.set_classifiers(other.get_classifiers())
             # language is handled below
         else:
             for attr in SC_COPYABLE_FIELDS:
@@ -423,6 +436,17 @@ class Metadata(object):
             if len(other_comments.strip()) > len(my_comments.strip()):
                 self.comments = other_comments
 
+            # Copy all the non-none classifiers
+            if callable(getattr(other, 'get_classifiers', None)):
+                d = self.get_classifiers()
+                s = other.get_classifiers()
+                d.update([v for v in s.iteritems() if v[1] is not None])
+                self.set_classifiers(d)
+            else:
+                # other structure not Metadata. Copy the top-level classifiers
+                for attr in TOP_LEVEL_CLASSIFIERS:
+                    copy_not_none(self, other, attr)
+
         other_lang = getattr(other, 'language', None)
         if other_lang and other_lang.lower() != 'und':
             self.language = other_lang