1 // Copyright (c) 2012 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_SEQUENCE_CHECKER_H_ 6 #define BASE_SEQUENCE_CHECKER_H_ 7 8 #include "base/sequence_checker_impl.h" 9 10 namespace base { 11 12 // Do nothing implementation, for use in release mode. 13 // 14 // Note: You should almost always use the SequenceChecker class to get 15 // the right version for your build configuration. 16 class SequenceCheckerDoNothing { 17 public: 18 bool CalledOnValidSequence() const { return true; } 19 20 void DetachFromSequence() {} 21 }; 22 23 // SequenceChecker is a helper class to verify that calls to some methods of a 24 // class are sequenced. Calls are sequenced when they are issued: 25 // - From tasks posted to SequencedTaskRunners or SingleThreadTaskRunners bound 26 // to the same sequence, or, 27 // - From a single thread outside of any task. 28 // 29 // Example: 30 // class MyClass { 31 // public: 32 // void Foo() { 33 // DCHECK(sequence_checker_.CalledOnValidSequence()); 34 // ... (do stuff) ... 35 // } 36 // 37 // private: 38 // SequenceChecker sequence_checker_; 39 // } 40 // 41 // In Release mode, CalledOnValidSequence() will always return true. 42 #if DCHECK_IS_ON() 43 class SequenceChecker : public SequenceCheckerImpl { 44 }; 45 #else 46 class SequenceChecker : public SequenceCheckerDoNothing { 47 }; 48 #endif // DCHECK_IS_ON() 49 50 } // namespace base 51 52 #endif // BASE_SEQUENCE_CHECKER_H_ 53
