Refactor sync-specific parts out of SyncNotifier/SyncNotifierObserver

sync/notifier/invalidation_notifier_base.cc

Index: sync/notifier/invalidation_notifier_base.cc
diff --git a/sync/notifier/invalidation_notifier_base.cc b/sync/notifier/invalidation_notifier_base.cc
new file mode 100644
index 0000000000000000000000000000000000000000..bc930fcfe578b1a3ae628e6b2bc2ba1bc44323e8
--- /dev/null
+++ b/sync/notifier/invalidation_notifier_base.cc
@@ -0,0 +1,63 @@
+// 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/invalidation_notifier_base.h"
+
+#include "base/stl_util.h"
+
+namespace syncer {
+
+InvalidationNotifierBase::InvalidationNotifierBase() {}
+InvalidationNotifierBase::~InvalidationNotifierBase() {}
+
+void InvalidationNotifierBase::AddHandler(SyncNotifierObserver* observer) {
+  observers_.AddObserver(observer);
+}
+void InvalidationNotifierBase::RemoveHandler(SyncNotifierObserver* observer) {
+  observers_.RemoveObserver(observer);
+  UpdateObjectIdObserverMap();
+}
+
+ObjectIdSet InvalidationNotifierBase::UpdateObjectIdObserverMap() {
+  ObjectIdSet ids_in_map;
+  id_to_observer_map_.clear();
+  if (observers_.might_have_observers()) {

[akalin, 2012/07/11 00:10:24]

why avoid the FOR_EACH_OBSERVER macro here?

[dcheng, 2012/07/11 05:45:28]

We need the return values. It might be possible to use some really clever macro
expansion to get this to work with FOR_EACH_OBSERVER, but most other places that
need that just inline the logic.

[akalin, 2012/07/11 20:27:02]

Ah, I missed that.  Yeah, that's another reason why that observer method is
problematic -- now you can't fully abstract away a SyncNotifier on another
thread (because you then have to require that that observer method is callable
from any thread).

+    ObserverListBase<SyncNotifierObserver>::Iterator observer_it(observers_);
+    SyncNotifierObserver* observer;
+    while ((observer = observer_it.GetNext()) != NULL) {
+      const ObjectIdSet& ids = observer->GetHandledIds();
+      for (ObjectIdSet::const_iterator it = ids.begin(); it != ids.end();
+           ++it) {
+        DCHECK(!ContainsKey(id_to_observer_map_, *it));
+        id_to_observer_map_[*it] = observer;
+        ids_in_map.insert(*it);
+      }
+    }
+  }
+  return ids_in_map;
+}
+
+void InvalidationNotifierBase::DispatchInvalidationsToObservers(
+    const ObjectIdPayloadMap& id_payloads,
+    IncomingNotificationSource source) {
+  std::map<SyncNotifierObserver*, ObjectIdPayloadMap> dispatch_map;
+  for (ObjectIdPayloadMap::const_iterator it = id_payloads.begin();
+       it != id_payloads.end(); ++it) {
+    ObjectIdObserverMap::const_iterator find_it =
+        id_to_observer_map_.find(it->first);
+    // If we get an invalidation for an object ID that we can't map to an
+    // observer, just drop it--the observer was unregistered while the
+    // invalidation was in flight.
+    if (find_it == id_to_observer_map_.end())
+      continue;
+    dispatch_map[find_it->second].insert(*it);
+  }
+  for (std::map<SyncNotifierObserver*, ObjectIdPayloadMap>::const_iterator it =
+       dispatch_map.begin(); it != dispatch_map.end(); ++it) {
+    DCHECK(observers_.HasObserver(it->first));
+    it->first->OnIncomingNotification(it->second, source);
+  }
+}
+
+}  // namespace syncer