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 13 namespace 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. 20 class 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
