[Sync] Avoid unregistering object IDs on shutdown

sync/notifier/sync_notifier_registrar.cc

Index: sync/notifier/sync_notifier_registrar.cc
diff --git a/sync/notifier/sync_notifier_registrar.cc b/sync/notifier/sync_notifier_registrar.cc
new file mode 100644
index 0000000000000000000000000000000000000000..596cc6adc7dcb5759296132aa06dc4276556a10f
--- /dev/null
+++ b/sync/notifier/sync_notifier_registrar.cc
@@ -0,0 +1,127 @@
+// 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.
+
+#include "sync/notifier/sync_notifier_registrar.h"
+
+#include <cstddef>
+#include <utility>
+
+#include "base/logging.h"
+
+namespace syncer {
+
+SyncNotifierRegistrar::SyncNotifierRegistrar() {}
+
+SyncNotifierRegistrar::~SyncNotifierRegistrar() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+}
+
+void SyncNotifierRegistrar::RegisterHandler(SyncNotifierObserver* handler) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  CHECK(handler);
+  CHECK(!handlers_.HasObserver(handler));
+  handlers_.AddObserver(handler);
+}
+
+void SyncNotifierRegistrar::UpdateRegisteredIds(
+    SyncNotifierObserver* handler,
+    const ObjectIdSet& ids) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  CHECK(handler);
+  CHECK(handlers_.HasObserver(handler));
+  // Remove all existing entries for |handler|.
+  for (IdHandlerMap::iterator it = id_to_handler_map_.begin();
+       it != id_to_handler_map_.end(); ) {
+    if (it->second == handler) {
+      IdHandlerMap::iterator erase_it = it;
+      ++it;
+      id_to_handler_map_.erase(erase_it);
+    } else {
+      ++it;
+    }
+  }
+
+  // Now add the entries for |handler|. We keep track of the last insertion
+  // point so we only traverse the map once to insert all the new entries.
+  IdHandlerMap::iterator insert_it = id_to_handler_map_.begin();
+  for (ObjectIdSet::const_iterator it = ids.begin(); it != ids.end(); ++it) {
+    insert_it =
+        id_to_handler_map_.insert(insert_it, std::make_pair(*it, handler));
+    CHECK_EQ(handler, insert_it->second)
+        << "Duplicate registration: trying to register "
+        << ObjectIdToString(insert_it->first) << " for "
+        << handler << " when it's already registered for "
+        << insert_it->second;
+  }
+}
+
+void SyncNotifierRegistrar::UnregisterHandler(SyncNotifierObserver* handler) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  CHECK(handler);
+  CHECK(handlers_.HasObserver(handler));
+  handlers_.RemoveObserver(handler);
+}
+
+ObjectIdSet SyncNotifierRegistrar::GetAllRegisteredIds() const {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  ObjectIdSet registered_ids;
+  for (IdHandlerMap::const_iterator it = id_to_handler_map_.begin();
+       it != id_to_handler_map_.end(); ++it) {
+    registered_ids.insert(it->first);
+  }
+  return registered_ids;
+}
+
+void SyncNotifierRegistrar::DispatchInvalidationsToHandlers(
+    const ObjectIdPayloadMap& id_payloads,
+    IncomingNotificationSource source) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  typedef std::map<SyncNotifierObserver*, ObjectIdPayloadMap> DispatchMap;
+  DispatchMap dispatch_map;
+  for (ObjectIdPayloadMap::const_iterator it = id_payloads.begin();
+       it != id_payloads.end(); ++it) {
+    SyncNotifierObserver* const handler = ObjectIdToHandler(it->first);
+    // Filter out invalidations for IDs with no handler.
+    if (handler)
+      dispatch_map[handler].insert(*it);
+  }
+
+  // Emit invalidations only for handlers in |handlers_|.
+  if (handlers_.might_have_observers()) {

[msw, 2012/08/09 05:20:26]

nit: consider making this an early return up top, to avoid the work above.

[akalin, 2012/08/10 01:28:08]

Done.

+    ObserverListBase<SyncNotifierObserver>::Iterator it(handlers_);
+    SyncNotifierObserver* handler = NULL;
+    while ((handler = it.GetNext()) != NULL) {
+      DispatchMap::const_iterator dispatch_it = dispatch_map.find(handler);
+      if (dispatch_it != dispatch_map.end()) {

[msw, 2012/08/09 05:20:26]

nit: remove unnecessary {}

[akalin, 2012/08/10 01:28:08]

Done.

+        handler->OnIncomingNotification(dispatch_it->second, source);
+      }
+    }
+  }
+}
+
+void SyncNotifierRegistrar::EmitOnNotificationsEnabled() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  FOR_EACH_OBSERVER(SyncNotifierObserver, handlers_, OnNotificationsEnabled());
+}
+
+void SyncNotifierRegistrar::EmitOnNotificationsDisabled(
+    NotificationsDisabledReason reason) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  FOR_EACH_OBSERVER(SyncNotifierObserver, handlers_,
+                    OnNotificationsDisabled(reason));
+}
+
+void SyncNotifierRegistrar::DetachFromThreadForTest() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  thread_checker_.DetachFromThread();
+}
+
+SyncNotifierObserver* SyncNotifierRegistrar::ObjectIdToHandler(
+    const invalidation::ObjectId& id) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  IdHandlerMap::const_iterator it = id_to_handler_map_.find(id);
+  return (it == id_to_handler_map_.end()) ? NULL : it->second;
+}
+
+}  // namespace syncer