Some refactoring of the DataStore API.

sugar/datastore/datastore.py

@@ -19,38 +19,48 @@ import gobject
 
 from sugar.datastore import dbus_helpers
 
-class DSObject(gobject.GObject):
+class DSMetadata(gobject.GObject):
     __gsignals__ = {
         'updated': (gobject.SIGNAL_RUN_FIRST, gobject.TYPE_NONE,
                     ([]))
     }
 
-    def __init__(self, object_id, metadata=None, file_path=None):
+    def __init__(self, props={}):
         gobject.GObject.__init__(self)
+        self._props = props
+
+    def __getitem__(self, key):
+        return self._props[key]
+
+    def __setitem__(self, key, value):
+        if not self._props.has_key(key) or self._props[key] != value:
+            self._props[key] = value
+            self.emit('updated')
+
+    def __delitem__(self, key):
+        del self._props[key]
+
+    def has_key(self, key):
+        return self._props.has_key(key)
+    
+    def get_dictionary(self):
+        return self._props
+
+class DSObject:
+    def __init__(self, object_id, metadata=None, file_path=None):
         self.object_id = object_id
         self._metadata = metadata
         self._file_path = file_path
 
-    def __getitem__(self, key):
-        return self.metadata[key]
-
-    def __setitem__(self, key, value):
-        if not self.metadata.has_key(key) or self.metadata[key] != value:
-            self.metadata[key] = value
-            self.emit('updated')
-
-    def __delitem__(self, key):
-        del self.metadata[key]
-
     def get_metadata(self):
         if self._metadata is None and not self.object_id is None:
-            self.set_metadata(dbus_helpers.get_properties(self.object_id))
+            metadata = DSMetadata(dbus_helpers.get_properties(self.object_id))
+            self._metadata = metadata
         return self._metadata
     
     def set_metadata(self, metadata):
         if self._metadata != metadata:
             self._metadata = metadata
-            self.emit('updated')
 
     metadata = property(get_metadata, set_metadata)
 
@@ -62,7 +72,6 @@ class DSObject(gobject.GObject):
     def set_file_path(self, file_path):
         if self._file_path != file_path:
             self._file_path = file_path
-            self.emit('updated')
 
     file_path = property(get_file_path, set_file_path)
 
@@ -71,23 +80,23 @@ def get(object_id):
     metadata = dbus_helpers.get_properties(object_id)
     file_path = dbus_helpers.get_filename(object_id)
 
-    ds_object = DSObject(object_id, metadata, file_path)
+    ds_object = DSObject(object_id, DSMetadata(metadata), file_path)
     # TODO: register the object for updates
     return ds_object
 
 def create():
-    return DSObject(object_id=None, metadata={}, file_path=None)
+    return DSObject(object_id=None, metadata=DSMetadata(), file_path=None)
 
 def write(ds_object, reply_handler=None, error_handler=None):
     logging.debug('datastore.write')
     if ds_object.object_id:
         dbus_helpers.update(ds_object.object_id,
-                            ds_object.metadata,
+                            ds_object.metadata.get_dictionary(),
                             ds_object.file_path,
                             reply_handler=reply_handler,
                             error_handler=error_handler)
     else:
-        ds_object.object_id = dbus_helpers.create(ds_object.metadata,
+        ds_object.object_id = dbus_helpers.create(ds_object.metadata.get_dictionary(),
                                                   ds_object.file_path)
         # TODO: register the object for updates
     logging.debug('Written object %s to the datastore.' % ds_object.object_id)
@@ -114,7 +123,7 @@ def find(query, sorting=None, limit=None, offset=None, reply_handler=None,
         object_id = props['uid']
         del props['uid']
 
-        ds_object = DSObject(object_id, props, file_path)
+        ds_object = DSObject(object_id, DSMetadata(props), file_path)
         objects.append(ds_object)
 
     return objects, total_count