michael@0: // Copyright (c) 2012 The Chromium Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: 
michael@0: #ifndef BASE_SEQUENCE_CHECKER_H_
michael@0: #define BASE_SEQUENCE_CHECKER_H_
michael@0: 
michael@0: #include "base/memory/ref_counted.h"
michael@0: 
michael@0: // See comments for the similar block in thread_checker.h.
michael@0: #if (!defined(NDEBUG) || defined(DCHECK_ALWAYS_ON))
michael@0: #define ENABLE_SEQUENCE_CHECKER 1
michael@0: #else
michael@0: #define ENABLE_SEQUENCE_CHECKER 0
michael@0: #endif
michael@0: 
michael@0: #if ENABLE_SEQUENCE_CHECKER
michael@0: #include "base/sequence_checker_impl.h"
michael@0: #endif
michael@0: 
michael@0: namespace base {
michael@0: 
michael@0: class SequencedTaskRunner;
michael@0: 
michael@0: // Do nothing implementation, for use in release mode.
michael@0: //
michael@0: // Note: You should almost always use the SequenceChecker class to get
michael@0: // the right version for your build configuration.
michael@0: class SequenceCheckerDoNothing {
michael@0:  public:
michael@0:   bool CalledOnValidSequencedThread() const {
michael@0:     return true;
michael@0:   }
michael@0: 
michael@0:   void DetachFromSequence() {}
michael@0: };
michael@0: 
michael@0: // SequenceChecker is a helper class used to help verify that some
michael@0: // methods of a class are called in sequence -- that is, called from
michael@0: // the same SequencedTaskRunner. It is a generalization of
michael@0: // ThreadChecker; see comments in sequence_checker_impl.h for details.
michael@0: //
michael@0: // Example:
michael@0: // class MyClass {
michael@0: //  public:
michael@0: //   void Foo() {
michael@0: //     DCHECK(sequence_checker_.CalledOnValidSequence());
michael@0: //     ... (do stuff) ...
michael@0: //   }
michael@0: //
michael@0: //  private:
michael@0: //   SequenceChecker sequence_checker_;
michael@0: // }
michael@0: //
michael@0: // In Release mode, CalledOnValidSequence will always return true.
michael@0: #if ENABLE_SEQUENCE_CHECKER
michael@0: class SequenceChecker : public SequenceCheckerImpl {
michael@0: };
michael@0: #else
michael@0: class SequenceChecker : public SequenceCheckerDoNothing {
michael@0: };
michael@0: #endif  // ENABLE_SEQUENCE_CHECKER
michael@0: 
michael@0: #undef ENABLE_SEQUENCE_CHECKER
michael@0: 
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_SEQUENCE_CHECKER_H_