1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_ 6 #define CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_ 7 8 #include "base/bind.h" 9 #include "base/callback.h" 10 #include "base/synchronization/waitable_event.h" 11 #include "content/public/browser/browser_thread.h" 12 13 // Runs code synchronously on the UI thread. Should never be called directly 14 // from the UI thread. To be used only within the provider classes. 15 class RunOnUIThreadBlocking { 16 public: 17 // Runs the provided runnable in the UI thread synchronously. 18 // The runnable argument can be defined using base::Bind. 19 template <typename Signature> 20 static void Run(base::Callback<Signature> runnable) { 21 DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI)); 22 base::WaitableEvent finished(false, false); 23 content::BrowserThread::PostTask(content::BrowserThread::UI, FROM_HERE, 24 base::Bind(&RunOnUIThreadBlocking::RunOnUIThread<Signature>, 25 runnable, &finished)); 26 finished.Wait(); 27 } 28 29 private: 30 template <typename Signature> 31 static void RunOnUIThread(base::Callback<Signature> runnable, 32 base::WaitableEvent* finished) { 33 DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::UI)); 34 runnable.Run(); 35 finished->Signal(); 36 } 37 }; 38 39 #endif // CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_ 40