IDBObserver: Lifetime Management: Adding Observer

content/child/indexed_db/indexed_db_dispatcher.cc

Index: content/child/indexed_db/indexed_db_dispatcher.cc
diff --git a/content/child/indexed_db/indexed_db_dispatcher.cc b/content/child/indexed_db/indexed_db_dispatcher.cc
index aa40cca350f2e8548188b939f202ec53a261f290..47e82099cae5ab3a835a15f17f03af79f46ce8a1 100644
--- a/content/child/indexed_db/indexed_db_dispatcher.cc
+++ b/content/child/indexed_db/indexed_db_dispatcher.cc
@@ -30,6 +30,7 @@ using blink::WebIDBDatabaseCallbacks;
 using blink::WebIDBDatabaseError;
 using blink::WebIDBKey;
 using blink::WebIDBMetadata;
+using blink::WebIDBObserver;
 using blink::WebIDBValue;
 using blink::WebString;
 using blink::WebVector;
@@ -167,6 +168,39 @@ bool IndexedDBDispatcher::Send(IPC::Message* msg) {
   return thread_safe_sender_->Send(msg);
 }
 
+int32_t IndexedDBDispatcher::AddIDBObserver(
+    int32_t ipc_database_id,
+    int64_t transaction_id,
+    std::unique_ptr<WebIDBObserver> observer) {
+  int32_t observer_id = observers_.Add(observer.release());
+  Send(new IndexedDBHostMsg_DatabaseObserve(ipc_database_id, transaction_id,
+                                            observer_id));
+  return observer_id;
+}
+
+std::vector<int32_t> IndexedDBDispatcher::RemoveIDBObserversFromDatabase(
+    int32_t ipc_database_id,
+    std::unique_ptr<WebIDBObserver> observer,
+    const std::vector<int32_t>& database_observer_ids) {
+  std::vector<int32_t> observer_ids_to_remove;
+  for (uint32_t i = 0; i < database_observer_ids.size(); i++) {
+    if (observers_.Lookup(database_observer_ids[i]) == observer.get()) {

[Marijn Kruisselbrink, 2016/06/24 00:48:09]

I'm confused about this check. observers_ owns WebIDBObserver instances, so it
should never be possible to have a unique_ptr that points to a WebIDBObserver
instance that is also in observers_ (if you would have such a pointer the
observer would end up being deleted twice, as it has two owners).

In other words, this check will always return false, or cause crashes.

+      observers_.Remove(database_observer_ids[i]);
+      observer_ids_to_remove.push_back(database_observer_ids[i]);
+    }
+  }
+  Send(new IndexedDBHostMsg_DatabaseUnobserve(ipc_database_id,
+                                              observer_ids_to_remove));
+  return observer_ids_to_remove;
+}
+
+void IndexedDBDispatcher::RemoveIDBObservers(
+    const std::vector<int32_t>& observer_ids_to_remove) {
+  for (uint32_t i = 0; i < observer_ids_to_remove.size(); i++) {
+    observers_.Remove(observer_ids_to_remove[i]);
+  }
+}
+
 void IndexedDBDispatcher::RequestIDBCursorAdvance(
     unsigned long count,
     WebIDBCallbacks* callbacks_ptr,