IDBObserver: Lifetime Management: Adding Observer

content/browser/indexed_db/indexed_db_dispatcher_host.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.
 
 #include "content/browser/indexed_db/indexed_db_dispatcher_host.h"
 
 #include <stddef.h>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 175 matching lines @@
     connection->Close();
     delete connection;
     return -1;
   }
   int32_t ipc_database_id = database_dispatcher_host_->map_.Add(connection);
   context()->ConnectionOpened(origin, connection);
   database_dispatcher_host_->database_origin_map_[ipc_database_id] = origin;
   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_)
     return;
   database_dispatcher_host_->transaction_size_map_[host_transaction_id] = 0;
   database_dispatcher_host_->transaction_origin_map_[host_transaction_id] =
       origin;
 }
 
 int64_t IndexedDBDispatcherHost::HostTransactionId(int64_t transaction_id) {
@@ skipping 307 matching lines @@
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseCreateObjectStore,
                         OnCreateObjectStore)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseDeleteObjectStore,
                         OnDeleteObjectStore)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseCreateTransaction,
                         OnCreateTransaction)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseClose, OnClose)
     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)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseSetIndexKeys, OnSetIndexKeys)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseSetIndexesReady,
                         OnSetIndexesReady)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseOpenCursor, OnOpenCursor)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseCount, OnCount)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseDeleteRange, OnDeleteRange)
     IPC_MESSAGE_HANDLER(IndexedDBHostMsg_DatabaseClear, OnClear)
@@ skipping 89 matching lines @@
   if (!connection)
     return;
   if (connection->IsConnected())
     connection->Close();
   parent_->context()->ConnectionClosed(database_origin_map_[ipc_object_id],
                                        connection);
   database_origin_map_.erase(ipc_object_id);
   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());
   IndexedDBConnection* connection =
       parent_->GetOrTerminateProcess(&map_, params.ipc_database_id);
   if (!connection || !connection->IsConnected())
     return;
 
   scoped_refptr<IndexedDBCallbacks> callbacks(new IndexedDBCallbacks(
       parent_, params.ipc_thread_id, params.ipc_callbacks_id));
@@ skipping 400 matching lines @@
     DLOG(ERROR) << "Unable to reset prefetch";
 }
 
 void IndexedDBDispatcherHost::CursorDispatcherHost::OnDestroyed(
     int32_t ipc_object_id) {
   DCHECK(parent_->context()->TaskRunner()->RunsTasksOnCurrentThread());
   parent_->DestroyObject(&map_, ipc_object_id);
 }
 
 }  // namespace content