IDBObserver: Lifetime Management: Adding Observer

content/browser/indexed_db/indexed_db_dispatcher_host.cc

Index: content/browser/indexed_db/indexed_db_dispatcher_host.cc
diff --git a/content/browser/indexed_db/indexed_db_dispatcher_host.cc b/content/browser/indexed_db/indexed_db_dispatcher_host.cc
index 96cad054d68c0110179e1aeb1e3a8c516ae73e60..c23d66938b1296cb84caa6204b546db45c2453cd 100644
--- a/content/browser/indexed_db/indexed_db_dispatcher_host.cc
+++ b/content/browser/indexed_db/indexed_db_dispatcher_host.cc
@@ -193,6 +193,13 @@ int32_t IndexedDBDispatcherHost::Add(IndexedDBConnection* connection,
   return ipc_database_id;
 }
 
+int64_t
+IndexedDBDispatcherHost::DatabaseDispatcherHost::GenerateObserverAndThreadId(
+    int32_t observer_id,
+    int32_t ipc_thread_id) {
+  return observer_id | (static_cast<uint64_t>(ipc_thread_id) << 32);
+}
+
 void IndexedDBDispatcherHost::RegisterTransactionId(int64_t host_transaction_id,
                                                     const url::Origin& origin) {
   if (!database_dispatcher_host_)
@@ -520,6 +527,7 @@ bool IndexedDBDispatcherHost::DatabaseDispatcherHost::OnMessageReceived(
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseVersionChangeIgnored,
                         OnVersionChangeIgnored)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseDestroyed, OnDestroyed)
+    IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseObserve, OnObserve)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseGet, OnGet)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseGetAll, OnGetAll)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabasePut, OnPutWrapper)
@@ -629,6 +637,47 @@ void IndexedDBDispatcherHost::DatabaseDispatcherHost::OnDestroyed(
   parent_->DestroyObject(&map_, ipc_object_id);
 }
 
+void IndexedDBDispatcherHost::DatabaseDispatcherHost::OnObserve(
+    int32_t ipc_thread_id,
+    int32_t ipc_database_id,
+    int64_t transaction_id,
+    int32_t observer_id) {

[dmurph, 2016/06/17 09:05:06]

can your rename the int32_t version of observer_id to local_observer_id? That
makes it a little more clear that it's not a global identifier (or if you have a
better name go for it).

[palakj1, 2016/06/18 05:13:40]

It's only local to the renderer thread right, not to the host? Should I directly
send <ipc_thread_id.front_end_observer_id> in the message instead?

Also our id's rest on database backend, not the dispatcher_host. Would
ipc_thread_id.front_end_observer_id be unique for the database?
Do I need to inject the dispatcher_host id as well?

+  DCHECK(parent_->context()->TaskRunner()->RunsTasksOnCurrentThread());
+  IndexedDBConnection* connection =
+      parent_->GetOrTerminateProcess(&map_, ipc_database_id);
+  if (!connection || !connection->IsConnected())
+    return;
+  int64_t observer_thread_id =
+      GenerateObserverAndThreadId(observer_id, ipc_thread_id);
+
+  observers_.push_back(std::make_pair(observer_id, observer_thread_id));

[dmurph, 2016/06/17 09:05:06]

You need to figure out how to store these so that you can use this list in the
destructor to remove the observers from the database. I would suggest maybe
storing map<database_id, vector<observer_and_thread_id>>, so you can lookup each
database once and then remove all observers for that database.

+  connection->database()->Observe(parent_->HostTransactionId(transaction_id),
+                                  observer_thread_id);
+}
+
+void IndexedDBDispatcherHost::DatabaseDispatcherHost::OnUnobserve(
+    int32_t ipc_thread_id,
+    int32_t ipc_database_id,
+    std::vector<int32_t> remove_observers) {
+  DCHECK(parent_->context()->TaskRunner()->RunsTasksOnCurrentThread());
+  IndexedDBConnection* connection =
+      parent_->GetOrTerminateProcess(&map_, ipc_database_id);
+  if (!connection || !connection->IsConnected())
+    return;
+  std::vector<int64_t> observersToRemove =
+      RemoveObservers(remove_observers, ipc_thread_id);
+  connection->database()->Unobserve(observersToRemove);
+}
+
+std::vector<int64_t>
+IndexedDBDispatcherHost::DatabaseDispatcherHost::RemoveObservers(
+    std::vector<int32_t> remove_observers,
+    int32_t ipc_database_id) {
+  // TODO(palakj): remove from observers_ and return vector of the hashed id.
+  std::vector<int64_t> observersToRemove;
+  return observersToRemove;
+}
+
 void IndexedDBDispatcherHost::DatabaseDispatcherHost::OnGet(
     const IndexedDBHostMsg_DatabaseGet_Params& params) {
   DCHECK(parent_->context()->TaskRunner()->RunsTasksOnCurrentThread());