Bug #1902313: Option to mark all books with annotations/bookmarks

Provided a formatter function annotation_count() that returns the number of annotations for a book

src/calibre/db/backend.py

@@ -1948,6 +1948,12 @@ class DB(object):
                 self.execute('DELETE FROM annotations_dirtied')
         return changed
 
+    def annotation_count_for_book(self, book_id):
+        with self.conn:
+            c = self.execute('SELECT count(id) FROM annotations WHERE book=?', (book_id,))
+            r = c.fetchone()[0]
+        return r
+
     def conversion_options(self, book_id, fmt):
         for (data,) in self.conn.get('SELECT data FROM conversion_options WHERE book=? AND format=?', (book_id, fmt.upper())):
             if data:

src/calibre/db/cache.py

@@ -2329,6 +2329,10 @@ class Cache(object):
     def all_annotations_for_book(self, book_id):
         return tuple(self.backend.all_annotations_for_book(book_id))
 
+    @read_api
+    def annotation_count_for_book(self, book_id):
+        return self.backend.annotation_count_for_book(book_id)
+
     @read_api
     def all_annotation_users(self):
         return tuple(self.backend.all_annotation_users())

src/calibre/utils/formatter_functions.py

@@ -1181,6 +1181,26 @@ class BuiltinOndevice(BuiltinFormatterFunction):
         return _('This function can be used only in the GUI')
 
 
+class BuiltinAnnotationCount(BuiltinFormatterFunction):
+    name = 'annotation_count'
+    arg_count = 0
+    category = 'Get values from metadata'
+    __doc__ = doc = _('annotation_count() -- return the total number of annotations '
+                      'of all types attached to the current book. '
+                      'This function works only in the GUI.')
+
+    def evaluate(self, formatter, kwargs, mi, locals):
+        if hasattr(mi, '_proxy_metadata'):
+            try:
+                from calibre.gui2.ui import get_gui
+                c = get_gui().current_db.new_api.annotation_count_for_book(mi.id)
+                return '' if c == 0 else unicode_type(c)
+            except:
+                return _('Failed to fetch annotation count')
+            return ''
+        return _('This function can be used only in the GUI')
+
+
 class BuiltinSeriesSort(BuiltinFormatterFunction):
     name = 'series_sort'
     arg_count = 0
@@ -1808,7 +1828,7 @@ _formatter_builtins = [
     BuiltinSwapAroundComma(), BuiltinSwitch(),
     BuiltinTemplate(), BuiltinTest(), BuiltinTitlecase(),
     BuiltinToday(), BuiltinTransliterate(), BuiltinUppercase(),
-    BuiltinUserCategories(), BuiltinVirtualLibraries()
+    BuiltinUserCategories(), BuiltinVirtualLibraries(), BuiltinAnnotationCount()
 ]