rtc_base/async_invoker_inl.h

/*
 *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */

#ifndef RTC_BASE_ASYNC_INVOKER_INL_H_
#define RTC_BASE_ASYNC_INVOKER_INL_H_

#include "api/scoped_refptr.h"
#include "rtc_base/event.h"
#include "rtc_base/message_handler.h"
#include "rtc_base/ref_counted_object.h"
#include "rtc_base/third_party/sigslot/sigslot.h"
#include "rtc_base/thread.h"
#include "rtc_base/thread_annotations.h"

namespace rtc {

class AsyncInvoker;

// Helper class for AsyncInvoker. Runs a task and triggers a callback
// on the calling thread if necessary.
class AsyncClosure {
 public:
  explicit AsyncClosure(AsyncInvoker* invoker);
  virtual ~AsyncClosure();
  // Runs the asynchronous task, and triggers a callback to the calling
  // thread if needed. Should be called from the target thread.
  virtual void Execute() = 0;

 protected:
  AsyncInvoker* invoker_;
  // Reference counted so that if the AsyncInvoker destructor finishes before
  // an AsyncClosure's destructor that's about to call
  // "invocation_complete_->Set()", it's not dereferenced after being
  // destroyed.
  scoped_refptr<RefCountedObject<Event>> invocation_complete_;
};

// Simple closure that doesn't trigger a callback for the calling thread.
template <class FunctorT>
class FireAndForgetAsyncClosure : public AsyncClosure {
 public:
  explicit FireAndForgetAsyncClosure(AsyncInvoker* invoker, FunctorT&& functor)
      : AsyncClosure(invoker), functor_(std::forward<FunctorT>(functor)) {}
  virtual void Execute() { functor_(); }

 private:
  typename std::decay<FunctorT>::type functor_;
};

}  // namespace rtc

#endif  // RTC_BASE_ASYNC_INVOKER_INL_H_