Implement custom book data API

src/calibre/db/backend.py

@@ -1175,5 +1175,46 @@ class DB(object):
                         self.rmtree(parent, permanent=permanent)
         self.conn.executemany(
             'DELETE FROM books WHERE id=?', [(x,) for x in path_map])
+
+    def add_custom_data(self, name, val_map, delete_first):
+        if delete_first:
+            self.conn.execute('DELETE FROM books_plugin_data WHERE name=?', (name, ))
+        self.conn.executemany(
+            'INSERT OR REPLACE INTO books_plugin_data (book, name, val) VALUES (?, ?, ?)',
+            [(book_id, name, json.dumps(val, default=to_json))
+                    for book_id, val in val_map.iteritems()])
+
+    def get_custom_book_data(self, name, book_ids, default=None):
+        book_ids = frozenset(book_ids)
+        def safe_load(val):
+            try:
+                return json.loads(val, object_hook=from_json)
+            except:
+                return default
+
+        if len(book_ids) == 1:
+            bid = next(iter(book_ids))
+            ans = {book_id:safe_load(val) for book_id, val in
+                   self.conn.execute('SELECT book, val FROM books_plugin_data WHERE book=? AND name=?', (bid, name))}
+            return ans or {bid:default}
+
+        ans = {}
+        for book_id, val in self.conn.execute(
+            'SELECT book, val FROM books_plugin_data WHERE name=?', (name,)):
+            if not book_ids or book_id in book_ids:
+                val = safe_load(val)
+                ans[book_id] = val
+        return ans
+
+    def delete_custom_book_data(self, name, book_ids):
+        if book_ids:
+            self.conn.executemany('DELETE FROM books_plugin_data WHERE book=? AND name=?',
+                                  [(book_id, name) for book_id in book_ids])
+        else:
+            self.conn.execute('DELETE FROM books_plugin_data WHERE name=?', (name,))
+
+    def get_ids_for_custom_book_data(self, name):
+        return frozenset(r[0] for r in self.conn.execute('SELECT book FROM books_plugin_data WHERE name=?', (name,)))
+
    # }}}
 

src/calibre/db/cache.py

@@ -1147,6 +1147,36 @@ class Cache(object):
             else:
                 table.remove_books(book_ids, self.backend)
 
+    @write_api
+    def add_custom_book_data(self, name, val_map, delete_first=False):
+        ''' Add data for name where val_map is a map of book_ids to values. If
+        delete_first is True, all previously stored data for name will be
+        removed. '''
+        missing = frozenset(val_map) - self._all_book_ids()
+        if missing:
+            raise ValueError('add_custom_book_data: no such book_ids: %d'%missing)
+        self.backend.add_custom_data(name, val_map, delete_first)
+
+    @read_api
+    def get_custom_book_data(self, name, book_ids=(), default=None):
+        ''' Get data for name. By default returns data for all book_ids, pass
+        in a list of book ids if you only want some data. Returns a map of
+        book_id to values. If a particular value could not be decoded, uses
+        default for it. '''
+        return self.backend.get_custom_book_data(name, book_ids, default)
+
+    @write_api
+    def delete_custom_book_data(self, name, book_ids=()):
+        ''' Delete data for name. By default deletes all data, if you only want
+        to delete data for some book ids, pass in a list of book ids. '''
+        self.backend.delete_custom_book_data(name, book_ids)
+
+    @read_api
+    def get_ids_for_custom_book_data(self, name):
+        ''' Return the set of book ids for which name has data. '''
+        return self.backend.get_ids_for_custom_book_data(name)
+
+
     # }}}
 
 class SortKey(object):  # {{{

src/calibre/db/legacy.py

@@ -216,6 +216,29 @@ class LibraryDatabase(object):
 
     # }}}
 
+    # Custom data {{{
+    def add_custom_book_data(self, book_id, name, val):
+        self.new_api.add_custom_book_data(name, {book_id:val})
+
+    def add_multiple_custom_book_data(self, name, val_map, delete_first=False):
+        self.new_api.add_custom_book_data(name, val_map, delete_first=delete_first)
+
+    def get_custom_book_data(self, book_id, name, default=None):
+        return self.new_api.get_custom_book_data(name, book_ids={book_id}, default=default).get(book_id, default)
+
+    def get_all_custom_book_data(self, name, default=None):
+        return self.new_api.get_custom_book_data(name, default=default)
+
+    def delete_custom_book_data(self, book_id, name):
+        self.new_api.delete_custom_book_data(name, book_ids=(book_id,))
+
+    def delete_all_custom_book_data(self, name):
+        self.new_api.delete_custom_book_data(name)
+
+    def get_ids_for_custom_book_data(self, name):
+        return list(self.new_api.get_ids_for_custom_book_data(name))
+    # }}}
+
     # Private interface {{{
 
     def __iter__(self):

src/calibre/db/tests/legacy.py

@@ -245,3 +245,34 @@ class LegacyTest(BaseTest):
 
     # }}}
 
+    def test_legacy_custom_data(self):  # {{{
+        'Test the API for custom data storage'
+        legacy, old = self.init_legacy(self.cloned_library), self.init_old(self.cloned_library)
+        for name in ('name1', 'name2', 'name3'):
+            T = partial(ET, 'add_custom_book_data', old=old, legacy=legacy)
+            T((1, name, 'val1'))(self)
+            T((2, name, 'val2'))(self)
+            T((3, name, 'val3'))(self)
+            T = partial(ET, 'get_ids_for_custom_book_data', old=old, legacy=legacy)
+            T((name,))(self)
+            T = partial(ET, 'get_custom_book_data', old=old, legacy=legacy)
+            T((1, name, object()))
+            T((9, name, object()))
+            T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
+            T((name, object()))
+            T((name+'!', object()))
+            T = partial(ET, 'delete_custom_book_data', old=old, legacy=legacy)
+            T((name, 1))
+            T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
+            T((name, object()))
+            T = partial(ET, 'delete_all_custom_book_data', old=old, legacy=legacy)
+            T((name))
+            T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
+            T((name, object()))
+
+        T = partial(ET, 'add_multiple_custom_book_data', old=old, legacy=legacy)
+        T(('n', {1:'val1', 2:'val2'}))(self)
+        T = partial(ET, 'get_all_custom_book_data', old=old, legacy=legacy)
+        T(('n', object()))
+        old.close()
+    # }}}