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