IDBObserver: Lifetime Management: Adding Observer

third_party/WebKit/Source/modules/indexeddb/IDBObserver.cpp

 // Copyright 2016 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 "modules/indexeddb/IDBObserver.h"
 
 #include "bindings/core/v8/ExceptionState.h"
+#include "bindings/core/v8/ExceptionStatePlaceholder.h"
 #include "bindings/modules/v8/ToV8ForModules.h"
 #include "bindings/modules/v8/V8BindingForModules.h"
+#include "core/dom/ExceptionCode.h"
+#include "modules/indexeddb/IDBDatabase.h"
 #include "modules/indexeddb/IDBObserverCallback.h"
 #include "modules/indexeddb/IDBObserverInit.h"
 
 namespace blink {
 
 IDBObserver* IDBObserver::create(IDBObserverCallback& callback, const IDBObserverInit& options)
 {
     return new IDBObserver(callback, options);
 }
 
 IDBObserver::IDBObserver(IDBObserverCallback& callback, const IDBObserverInit& options)
     : m_callback(&callback)
     , m_transaction(options.transaction())
     , m_values(options.values())
     , m_noRecords(options.noRecords())
 {
 }
 
 IDBObserver::~IDBObserver() {}
 
 void IDBObserver::observe(IDBDatabase* database, IDBTransaction* transaction, ExceptionState& exceptionState)
 {
-    // TODO(palakj): Finish implementation.
+    if (transaction->isFinished() || transaction->isFinishing()) {
+        exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionFinishedErrorMessage);
+        return;
+    }
+    if (!transaction->isActive()) {
+        exceptionState.throwDOMException(TransactionInactiveError, IDBDatabase::transactionInactiveErrorMessage);
+        return;
+    }
+    if (!database->backend()) {
+        exceptionState.throwDOMException(InvalidStateError, IDBDatabase::databaseClosedErrorMessage);
+        return;
+    }
+    database->backend()->observe(this, transaction->id());
+}
+
+void IDBObserver::unobserve(IDBDatabase* database, ExceptionState& exceptionState)
+{
+    if (!database->backend()) {
+        exceptionState.throwDOMException(InvalidStateError, IDBDatabase::databaseClosedErrorMessage);
+        return;
+    }
+    database->backend()->unobserve(this);
 }
 
 DEFINE_TRACE(IDBObserver)
 {
     visitor->trace(m_callback);
 }
 
 } // namespace blink