1// Copyright (c) 2011 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 BASE_SYNCHRONIZATION_CANCELLATION_FLAG_H_ 6#define BASE_SYNCHRONIZATION_CANCELLATION_FLAG_H_ 7#pragma once 8 9#include "base/base_api.h" 10#include "base/atomicops.h" 11#include "base/threading/platform_thread.h" 12 13namespace base { 14 15// CancellationFlag allows one thread to cancel jobs executed on some worker 16// thread. Calling Set() from one thread and IsSet() from a number of threads 17// is thread-safe. 18// 19// This class IS NOT intended for synchronization between threads. 20class BASE_API CancellationFlag { 21 public: 22 CancellationFlag() : flag_(false) { 23#if !defined(NDEBUG) 24 set_on_ = PlatformThread::CurrentId(); 25#endif 26 } 27 ~CancellationFlag() {} 28 29 // Set the flag. May only be called on the thread which owns the object. 30 void Set(); 31 bool IsSet() const; // Returns true iff the flag was set. 32 33 private: 34 base::subtle::Atomic32 flag_; 35#if !defined(NDEBUG) 36 PlatformThreadId set_on_; 37#endif 38 39 DISALLOW_COPY_AND_ASSIGN(CancellationFlag); 40}; 41 42} // namespace base 43 44#endif // BASE_SYNCHRONIZATION_CANCELLATION_FLAG_H_ 45