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// 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_BLOCKING_UI_THREAD_ASYNC_REQUEST_H_
#define CHROME_BROWSER_ANDROID_PROVIDER_BLOCKING_UI_THREAD_ASYNC_REQUEST_H_
#include "base/bind.h"
#include "base/callback.h"
#include "base/synchronization/waitable_event.h"
#include "chrome/browser/android/provider/run_on_ui_thread_blocking.h"
#include "content/public/browser/browser_thread.h"
// Allows making async requests and blocking the current thread until the
// response arrives. The request is performed in the UI thread.
// Users of this class MUST call RequestCompleted when receiving the response.
// Cannot be called directly from the UI thread.
class BlockingUIThreadAsyncRequest {
public:
BlockingUIThreadAsyncRequest();
// Runs an asynchronous request, blocking the invoking thread until a response
// is received. Class users MUST call RequestCompleted when this happens.
// Make sure that the response is also delivered to the UI thread.
// The request argument can be defined using base::Bind.
template <typename Signature>
void RunAsyncRequestOnUIThreadBlocking(base::Callback<Signature> request) {
DCHECK(!content::BrowserThread::CurrentlyOn(content::BrowserThread::UI));
// Make the request in the UI thread.
request_completed_.Reset();
RunOnUIThreadBlocking::Run(
base::Bind(
&BlockingUIThreadAsyncRequest::RunRequestOnUIThread<Signature>,
request));
// Wait until the request callback invokes Finished.
request_completed_.Wait();
}
// Notifies about a finished request.
void RequestCompleted();
private:
template <typename Signature>
static void RunRequestOnUIThread(base::Callback<Signature> request) {
request.Run();
}
base::WaitableEvent request_completed_;
DISALLOW_COPY_AND_ASSIGN(BlockingUIThreadAsyncRequest);
};
#endif // CHROME_BROWSER_ANDROID_PROVIDER_BLOCKING_UI_THREAD_ASYNC_REQUEST_H_
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