IDBObserver: Lifetime Management: Adding Observer

content/browser/indexed_db/indexed_db_connection.cc

 // Copyright 2013 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_connection.h"
 
+#include "base/logging.h"
+#include "base/stl_util.h"
+
 namespace content {
 
 IndexedDBConnection::IndexedDBConnection(
     scoped_refptr<IndexedDBDatabase> database,
     scoped_refptr<IndexedDBDatabaseCallbacks> callbacks)
     : database_(database), callbacks_(callbacks), weak_factory_(this) {}
 
 IndexedDBConnection::~IndexedDBConnection() {}
 
 void IndexedDBConnection::Close() {
   if (!callbacks_.get())
     return;
   base::WeakPtr<IndexedDBConnection> this_obj = weak_factory_.GetWeakPtr();
   database_->Close(this, false /* forced */);
   if (this_obj) {
     database_ = nullptr;
     callbacks_ = nullptr;
+    active_observers_.clear();
   }
 }
 
 void IndexedDBConnection::ForceClose() {
   if (!callbacks_.get())
     return;
 
   // IndexedDBDatabase::Close() can delete this instance.
   base::WeakPtr<IndexedDBConnection> this_obj = weak_factory_.GetWeakPtr();
   scoped_refptr<IndexedDBDatabaseCallbacks> callbacks(callbacks_);
   database_->Close(this, true /* forced */);
   if (this_obj) {
     database_ = nullptr;
     callbacks_ = nullptr;
+    active_observers_.clear();
   }
   callbacks->OnForcedClose();
 }
 
 void IndexedDBConnection::VersionChangeIgnored() {
   if (!database_.get())
     return;
   database_->VersionChangeIgnored();
 }
 
 bool IndexedDBConnection::IsConnected() {
   return database_.get() != NULL;
 }
 
+// The observers begin listening to changes only once they are activated.
+void IndexedDBConnection::ActivatePendingObservers(
+    std::vector<std::unique_ptr<IndexedDBObserver>> pending_observers) {
+  for (auto& observer : pending_observers) {
+    active_observers_.push_back(std::move(observer));
+  }
+  pending_observers.clear();
+}
+
+void IndexedDBConnection::RemoveObservers(
+    const std::vector<int32_t>& observer_ids_to_remove) {
+  std::vector<int32_t> pending_observer_ids;
+  for (int32_t id_to_remove : observer_ids_to_remove) {
+    const auto& it = std::find_if(
+        active_observers_.begin(), active_observers_.end(),
+        [&id_to_remove](const std::unique_ptr<IndexedDBObserver>& o) {
+          return o->id() == id_to_remove;
+        });
+    if (it != active_observers_.end())
+      active_observers_.erase(it);
+    else
+      pending_observer_ids.push_back(id_to_remove);
+  }
+  if (!pending_observer_ids.empty())
+    database_->RemovePendingObservers(this, pending_observer_ids);
+}
+
 }  // namespace content