blob: b209ac168da4f7eea81d08df9cbe1fe665b1bc56 [file] [log] [blame]
// 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.
#ifndef CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_
#define CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_
#include "base/bind.h"
#include "base/callback.h"
#include "base/synchronization/waitable_event.h"
#include "base/task/post_task.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
// Runs code synchronously on the UI thread. Should never be called directly
// from the UI thread. To be used only within the provider classes.
class RunOnUIThreadBlocking {
public:
// Runs the provided runnable in the UI thread synchronously.
// The runnable argument can be defined using base::Bind.
template <typename Signature>
static void Run(base::Callback<Signature> runnable) {
DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
base::WaitableEvent finished(
base::WaitableEvent::ResetPolicy::AUTOMATIC,
base::WaitableEvent::InitialState::NOT_SIGNALED);
base::PostTaskWithTraits(
FROM_HERE, {content::BrowserThread::UI},
base::Bind(&RunOnUIThreadBlocking::RunOnUIThread<Signature>, runnable,
&finished));
finished.Wait();
}
private:
template <typename Signature>
static void RunOnUIThread(base::Callback<Signature> runnable,
base::WaitableEvent* finished) {
DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
runnable.Run();
finished->Signal();
}
};
#endif // CHROME_BROWSER_ANDROID_PROVIDER_RUN_ON_UI_THREAD_BLOCKING_H_