Add rel_path_keyword to @method (fd.o #11623)

4 files changed, 68 insertions, 13 deletions

diff --git a/dbus/decorators.py b/dbus/decorators.py
index 908d055..00cf20d 100644
--- a/dbus/decorators.py
+++ b/dbus/decorators.py
@@ -35,7 +35,8 @@ def method(dbus_interface, in_signature=None, out_signature=None,
         async_callbacks=None,
         sender_keyword=None, path_keyword=None, destination_keyword=None,
         message_keyword=None, connection_keyword=None,
-        utf8_strings=False, byte_arrays=False):
+        utf8_strings=False, byte_arrays=False,
+        rel_path_keyword=None):
     """Factory for decorators used to mark methods of a `dbus.service.Object`
     to be exported on the D-Bus.
 
@@ -86,8 +87,20 @@ def method(dbus_interface, in_signature=None, out_signature=None,
             case of "fallback paths" you'll usually want to use the object
             path in the method's implementation.
 
+            For fallback objects, `rel_path_keyword` (new in 0.82.2) is
+            likely to be more useful.
+
             :Since: 0.80.0?
 
+        `rel_path_keyword` : str or None
+            If not None (the default), the decorated method will receive
+            the destination object path, relative to the path at which the
+            object was exported, as a keyword argument with this
+            name. For non-fallback objects the relative path will always be
+            '/'.
+
+            :Since: 0.82.2
+
         `destination_keyword` : str or None
             If not None (the default), the decorated method will receive
             the destination bus name as a keyword argument with this name.
@@ -150,6 +163,8 @@ def method(dbus_interface, in_signature=None, out_signature=None,
 
         if sender_keyword:
             args.remove(sender_keyword)
+        if rel_path_keyword:
+            args.remove(rel_path_keyword)
         if path_keyword:
             args.remove(path_keyword)
         if destination_keyword:
@@ -174,6 +189,7 @@ def method(dbus_interface, in_signature=None, out_signature=None,
         func._dbus_out_signature = out_signature
         func._dbus_sender_keyword = sender_keyword
         func._dbus_path_keyword = path_keyword
+        func._dbus_rel_path_keyword = rel_path_keyword
         func._dbus_destination_keyword = destination_keyword
         func._dbus_message_keyword = message_keyword
         func._dbus_connection_keyword = connection_keyword
diff --git a/dbus/service.py b/dbus/service.py
index 8ffec3e..21165c5 100644
--- a/dbus/service.py
+++ b/dbus/service.py
@@ -33,7 +33,7 @@ except ImportError:
 
 import _dbus_bindings
 from dbus import SessionBus, Signature, Struct, validate_bus_name, \
-                 validate_object_path, INTROSPECTABLE_IFACE
+                 validate_object_path, INTROSPECTABLE_IFACE, ObjectPath
 from dbus.decorators import method, signal
 from dbus.exceptions import DBusException, \
                             NameExistsException, \
@@ -653,6 +653,29 @@ class Object(Interface):
                 keywords[parent_method._dbus_sender_keyword] = message.get_sender()
             if parent_method._dbus_path_keyword:
                 keywords[parent_method._dbus_path_keyword] = message.get_path()
+            if parent_method._dbus_rel_path_keyword:
+                path = message.get_path()
+                rel_path = path
+                for exp in self._locations:
+                    # pathological case: if we're exported in two places,
+                    # one of which is a subtree of the other, then pick the
+                    # subtree by preference (i.e. minimize the length of
+                    # rel_path)
+                    if exp[0] is connection:
+                        if path == exp[1]:
+                            rel_path = '/'
+                            break
+                        if exp[1] == '/':
+                            # we already have rel_path == path at the beginning
+                            continue
+                        if path.startswith(exp[1] + '/'):
+                            # yes we're in this exported subtree
+                            suffix = path[len(exp[1]):]
+                            if len(suffix) < len(rel_path):
+                                rel_path = suffix
+                rel_path = ObjectPath(rel_path)
+                keywords[parent_method._dbus_rel_path_keyword] = rel_path
+
             if parent_method._dbus_destination_keyword:
                 keywords[parent_method._dbus_destination_keyword] = message.get_destination()
             if parent_method._dbus_message_keyword:
diff --git a/test/test-client.py b/test/test-client.py
index 050ed46..085c208 100755
--- a/test/test-client.py
+++ b/test/test-client.py
@@ -422,17 +422,32 @@ class TestDBusBindings(unittest.TestCase):
     def testFallbackObjectTrivial(self):
         obj = self.bus.get_object(NAME, OBJECT + '/Fallback')
         iface = dbus.Interface(obj, IFACE)
-        path, unique_name = iface.TestPathAndConnKeywords()
+        path, rel, unique_name = iface.TestPathAndConnKeywords()
         self.assertEquals(path, OBJECT + '/Fallback')
-        #self.assertEquals(rel, '/Badger/Mushroom')
+        self.assertEquals(rel, '/')
+        self.assertEquals(unique_name, obj.bus_name)
+
+    def testFallbackObjectNested(self):
+        obj = self.bus.get_object(NAME, OBJECT + '/Fallback/Nested')
+        iface = dbus.Interface(obj, IFACE)
+        path, rel, unique_name = iface.TestPathAndConnKeywords()
+        self.assertEquals(path, OBJECT + '/Fallback/Nested')
+        self.assertEquals(rel, '/')
+        self.assertEquals(unique_name, obj.bus_name)
+
+        obj = self.bus.get_object(NAME, OBJECT + '/Fallback/Nested/Badger/Mushroom')
+        iface = dbus.Interface(obj, IFACE)
+        path, rel, unique_name = iface.TestPathAndConnKeywords()
+        self.assertEquals(path, OBJECT + '/Fallback/Nested/Badger/Mushroom')
+        self.assertEquals(rel, '/Badger/Mushroom')
         self.assertEquals(unique_name, obj.bus_name)
 
     def testFallbackObject(self):
         obj = self.bus.get_object(NAME, OBJECT + '/Fallback/Badger/Mushroom')
         iface = dbus.Interface(obj, IFACE)
-        path, unique_name = iface.TestPathAndConnKeywords()
+        path, rel, unique_name = iface.TestPathAndConnKeywords()
         self.assertEquals(path, OBJECT + '/Fallback/Badger/Mushroom')
-        #self.assertEquals(rel, '/Badger/Mushroom')
+        self.assertEquals(rel, '/Badger/Mushroom')
         self.assertEquals(unique_name, obj.bus_name)
 
     def testTimeoutSync(self):
diff --git a/test/test-service.py b/test/test-service.py
index 4488eb1..10bebc5 100755
--- a/test/test-service.py
+++ b/test/test-service.py
@@ -74,20 +74,21 @@ class TestInterface(dbus.service.Interface):
         return False
 
 class Fallback(dbus.service.FallbackObject):
-    def __init__(self, bus_name, object_path=OBJECT + '/Fallback'):
-        super(Fallback, self).__init__(bus_name, object_path)
+    def __init__(self, conn, object_path=OBJECT + '/Fallback'):
+        super(Fallback, self).__init__(conn, object_path)
+        self.add_to_connection(conn, object_path + '/Nested')
 
-    @dbus.service.method(IFACE, in_signature='', out_signature='os',
-                         path_keyword='path', # rel_path_keyword='rel',
+    @dbus.service.method(IFACE, in_signature='', out_signature='oos',
+                         path_keyword='path', rel_path_keyword='rel',
                          connection_keyword='conn')
-    def TestPathAndConnKeywords(self, path=None, conn=None):
-        return path, conn.get_unique_name()
+    def TestPathAndConnKeywords(self, path=None, conn=None, rel=None):
+        return path, rel, conn.get_unique_name()
 
     @dbus.service.signal(IFACE, signature='s', rel_path_keyword='rel_path')
     def SignalOneString(self, test, rel_path=None):
         logger.info('SignalOneString(%r) @ %r', test, rel_path)
 
-    # Deprecated
+    # Deprecated usage
     @dbus.service.signal(IFACE, signature='ss', path_keyword='path')
     def SignalTwoStrings(self, test, test2, path=None):
         logger.info('SignalTwoStrings(%r, %r) @ %r', test, test2, path)