Start work on cache layer for new db backend

src/calibre/db/backend.py

@@ -478,7 +478,6 @@ class DB(object):
                 remove.append(data)
                 continue
 
-            self.custom_column_label_map[data['label']] = data['num']
             self.custom_column_num_map[data['num']] = \
                 self.custom_column_label_map[data['label']] = data
 
@@ -613,10 +612,31 @@ class DB(object):
 
         tables['size'] = SizeTable('size', self.field_metadata['size'].copy())
 
-        for label, data in self.custom_column_label_map.iteritems():
-            label = '#' + label
+        self.FIELD_MAP = {'id':0, 'title':1, 'authors':2, 'timestamp':3,
+             'size':4, 'rating':5, 'tags':6, 'comments':7, 'series':8,
+             'publisher':9, 'series_index':10, 'sort':11, 'author_sort':12,
+             'formats':13, 'path':14, 'pubdate':15, 'uuid':16, 'cover':17,
+             'au_map':18, 'last_modified':19, 'identifiers':20}
+
+        for k,v in self.FIELD_MAP.iteritems():
+            self.field_metadata.set_field_record_index(k, v, prefer_custom=False)
+
+        base = max(self.FIELD_MAP.itervalues())
+
+        for label_, data in self.custom_column_label_map.iteritems():
+            label = '#' + label_
             metadata = self.field_metadata[label].copy()
             link_table = self.custom_table_names(data['num'])[1]
+            self.FIELD_MAP[data['num']] = base = base+1
+            self.field_metadata.set_field_record_index(label_, base,
+                    prefer_custom=True)
+            if data['datatype'] == 'series':
+                # account for the series index column. Field_metadata knows that
+                # the series index is one larger than the series. If you change
+                # it here, be sure to change it there as well.
+                self.FIELD_MAP[str(data['num'])+'_index'] = base = base+1
+                self.field_metadata.set_field_record_index(label_+'_index', base,
+                            prefer_custom=True)
 
             if data['normalized']:
                 if metadata['is_multiple']:
@@ -634,6 +654,12 @@ class DB(object):
                         tables[label] = OneToOneTable(label, metadata)
             else:
                 tables[label] = OneToOneTable(label, metadata)
+
+        self.FIELD_MAP['ondevice'] = base = base+1
+        self.field_metadata.set_field_record_index('ondevice', base, prefer_custom=False)
+        self.FIELD_MAP['marked'] = base = base+1
+        self.field_metadata.set_field_record_index('marked', base, prefer_custom=False)
+
     # }}}
 
     @property

src/calibre/db/cache.py

@@ -7,5 +7,24 @@ __license__   = 'GPL v3'
 __copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
 __docformat__ = 'restructuredtext en'
 
+from calibre.db.locking import create_locks
+from calibre.db.fields import create_field
 
+class Cache(object):
+
+    def __init__(self, backend):
+        self.backend = backend
+        self.fields = {}
+        self.read_lock, self.write_lock = create_locks()
+
+    # Cache Layer API {{{
+
+    def init(self):
+        with self.write_lock:
+            self.backend.read_tables()
+
+            for field, table in self.backend.tables.iteritems():
+                self.fields[field] = create_field(field, table)
+
+    # }}}
 

src/calibre/db/fields.py

@@ -0,0 +1,114 @@
+#!/usr/bin/env python
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__   = 'GPL v3'
+__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
+__docformat__ = 'restructuredtext en'
+
+from calibre.db.tables import ONE_ONE, MANY_ONE, MANY_MANY
+
+class Field(object):
+
+    def __init__(self, name, table):
+        self.name, self.table = name, table
+        self.has_text_data = self.metadata['datatype'] in ('text', 'comments',
+                'series', 'enumeration')
+        self.table_type = self.table.table_type
+
+    @property
+    def metadata(self):
+        return self.table.metadata
+
+    def for_book(self, book_id, default_value=None):
+        '''
+        Return the value of this field for the book identified by book_id.
+        When no value is found, returns ``default_value``.
+        '''
+        raise NotImplementedError()
+
+    def ids_for_book(self, book_id):
+        '''
+        Return a tuple of items ids for items associated with the book
+        identified by book_ids. Returns an empty tuple if no such items are
+        found.
+        '''
+        raise NotImplementedError()
+
+    def books_for(self, item_id):
+        '''
+        Return the ids of all books associated with the item identified by
+        item_id as a tuple. An empty tuple is returned if no books are found.
+        '''
+        raise NotImplementedError()
+
+    def __iter__(self):
+        '''
+        Iterate over the ids for all values in this field
+        '''
+        raise NotImplementedError()
+
+class OneToOneField(Field):
+
+    def for_book(self, book_id, default_value=None):
+        return self.table.book_col_map.get(book_id, default_value)
+
+    def ids_for_book(self, book_id):
+        return (book_id,)
+
+    def books_for(self, item_id):
+        return (item_id,)
+
+    def __iter__(self):
+        return self.table.book_col_map.iterkeys()
+
+class ManyToOneField(Field):
+
+    def for_book(self, book_id, default_value=None):
+        ids = self.table.book_col_map.get(book_id, None)
+        if ids is not None:
+            ans = self.id_map[ids]
+        else:
+            ans = default_value
+        return ans
+
+    def ids_for_book(self, book_id):
+        ids = self.table.book_col_map.get(book_id, None)
+        if ids is None:
+            return ()
+        return ids
+
+    def books_for(self, item_id):
+        return self.table.col_book_map.get(item_id, ())
+
+    def __iter__(self):
+        return self.table.id_map.iterkeys()
+
+class ManyToManyField(Field):
+
+    def for_book(self, book_id, default_value=None):
+        ids = self.table.book_col_map.get(book_id, ())
+        if ids:
+            ans = tuple(self.id_map[i] for i in ids)
+        else:
+            ans = default_value
+        return ans
+
+    def ids_for_book(self, book_id):
+        return self.table.book_col_map.get(book_id, ())
+
+    def books_for(self, item_id):
+        return self.table.col_book_map.get(item_id, ())
+
+    def __iter__(self):
+        return self.table.id_map.iterkeys()
+
+def create_field(name, table):
+    cls = {
+            ONE_ONE : OneToOneField,
+            MANY_ONE : ManyToOneField,
+            MANY_MANY : ManyToManyField,
+        }[table.table_type]
+    return cls(name, table)
+

src/calibre/db/tables.py

@@ -17,6 +17,8 @@ from calibre.ebooks.metadata import author_to_author_sort
 
 _c_speedup = plugins['speedup'][0]
 
+ONE_ONE, MANY_ONE, MANY_MANY = xrange(3)
+
 def _c_convert_timestamp(val):
     if not val:
         return None
@@ -57,6 +59,8 @@ class OneToOneTable(Table):
     timestamp, size, etc.
     '''
 
+    table_type = ONE_ONE
+
     def read(self, db):
         self.book_col_map = {}
         idcol = 'id' if self.metadata['table'] == 'books' else 'book'
@@ -82,9 +86,10 @@ class ManyToOneTable(Table):
     Each book however has only one value for data of this type.
     '''
 
+    table_type = MANY_ONE
+
     def read(self, db):
         self.id_map = {}
-        self.extra_map = {}
         self.col_book_map = {}
         self.book_col_map = {}
         self.read_id_maps(db)
@@ -105,6 +110,9 @@ class ManyToOneTable(Table):
             self.col_book_map[row[1]].append(row[0])
             self.book_col_map[row[0]] = row[1]
 
+        for key, val in self.col_book_map:
+            self.col_book_map[key] = tuple(val)
+
 class ManyToManyTable(ManyToOneTable):
 
     '''
@@ -113,6 +121,8 @@ class ManyToManyTable(ManyToOneTable):
     book. For example: tags or authors.
     '''
 
+    table_type = MANY_MANY
+
     def read_maps(self, db):
         for row in db.conn.execute(
                 'SELECT book, {0} FROM {1}'.format(
@@ -124,6 +134,12 @@ class ManyToManyTable(ManyToOneTable):
                 self.book_col_map[row[0]] = []
             self.book_col_map[row[0]].append(row[1])
 
+        for key, val in self.col_book_map:
+            self.col_book_map[key] = tuple(val)
+
+        for key, val in self.book_col_map:
+            self.book_col_map[key] = tuple(val)
+
 class AuthorsTable(ManyToManyTable):
 
     def read_id_maps(self, db):
@@ -150,6 +166,12 @@ class FormatsTable(ManyToManyTable):
                     self.book_col_map[row[0]] = []
                 self.book_col_map[row[0]].append((row[1], row[2]))
 
+        for key, val in self.col_book_map:
+            self.col_book_map[key] = tuple(val)
+
+        for key, val in self.book_col_map:
+            self.book_col_map[key] = tuple(val)
+
 class IdentifiersTable(ManyToManyTable):
 
     def read_id_maps(self, db):
@@ -165,3 +187,9 @@ class IdentifiersTable(ManyToManyTable):
                     self.book_col_map[row[0]] = []
                 self.book_col_map[row[0]].append((row[1], row[2]))
 
+        for key, val in self.col_book_map:
+            self.col_book_map[key] = tuple(val)
+
+        for key, val in self.book_col_map:
+            self.book_col_map[key] = tuple(val)
+

src/calibre/db/view.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+# vim:fileencoding=UTF-8:ts=4:sw=4:sta:et:sts=4:ai
+from __future__ import (unicode_literals, division, absolute_import,
+                        print_function)
+
+__license__   = 'GPL v3'
+__copyright__ = '2011, Kovid Goyal <kovid@kovidgoyal.net>'
+__docformat__ = 'restructuredtext en'
+
+
+class View(object):
+
+    def __init__(self, cache):
+        self.cache = cache
+        self._field_idx_map = {}
+        for col, idx in cache.backend.FIELD_MAP.iteritems():
+            if isinstance(col, int):
+                pass # custom column
+            else:
+                self._field_idx_map[idx] = col
+