DBus: Bus::AddMatch and RemoveMatch support repeated rules.

dbus/bus.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // TODO(satorux):
 // - Handle "disconnected" signal.
 
 #include "dbus/bus.h"
 
 #include "base/bind.h"
@@ skipping 569 matching lines @@
 
   dbus_connection_remove_filter(connection_, filter_function, user_data);
   filter_functions_added_.erase(filter_data_pair);
   return true;
 }
 
 void Bus::AddMatch(const std::string& match_rule, DBusError* error) {
   DCHECK(connection_);
   AssertOnDBusThread();
 
-  if (match_rules_added_.find(match_rule) != match_rules_added_.end()) {
+  std::map<std::string, int>::iterator iter =
+      match_rules_added_.find(match_rule);
+  if (iter != match_rules_added_.end()) {
+    // The already existing rule's counter is incremented.
+    iter->second++;
+
     VLOG(1) << "Match rule already exists: " << match_rule;
     return;
   }
 
   dbus_bus_add_match(connection_, match_rule.c_str(), error);
-  match_rules_added_.insert(match_rule);
+  match_rules_added_[match_rule] = 1;
 }
 
-void Bus::RemoveMatch(const std::string& match_rule, DBusError* error) {
+bool Bus::RemoveMatch(const std::string& match_rule, DBusError* error) {
   DCHECK(connection_);
   AssertOnDBusThread();
 
-  if (match_rules_added_.find(match_rule) == match_rules_added_.end()) {
+  std::map<std::string, int>::iterator iter =
+      match_rules_added_.find(match_rule);
+  if (iter == match_rules_added_.end()) {
     LOG(ERROR) << "Requested to remove an unknown match rule: " << match_rule;
-    return;
+    return false;
   }
 
-  dbus_bus_remove_match(connection_, match_rule.c_str(), error);
-  match_rules_added_.erase(match_rule);
+  // The rule's counter is decremented and the rule is deleted when reachs 0.
+  iter->second--;
+  if (iter->second == 0) {
+    dbus_bus_remove_match(connection_, match_rule.c_str(), error);
+    match_rules_added_.erase(match_rule);
+  }
+  return true;
 }
 
 bool Bus::TryRegisterObjectPath(const ObjectPath& object_path,
                                 const DBusObjectPathVTable* vtable,
                                 void* user_data,
                                 DBusError* error) {
   DCHECK(connection_);
   AssertOnDBusThread();
 
   if (registered_object_paths_.find(object_path) !=
@@ skipping 223 matching lines @@
 }
 
 void Bus::OnDispatchStatusChangedThunk(DBusConnection* connection,
                                        DBusDispatchStatus status,
                                        void* data) {
   Bus* self = static_cast<Bus*>(data);
   self->OnDispatchStatusChanged(connection, status);
 }
 
 }  // namespace dbus