michael@0: // Copyright (c) 2006-2008 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_NON_THREAD_SAFE_H__
michael@0: #define BASE_NON_THREAD_SAFE_H__
michael@0: 
michael@0: #include "base/platform_thread.h"
michael@0: 
michael@0: // A helper class used to help verify that methods of a class are
michael@0: // called from the same thread.  One can inherit from this class and use
michael@0: // CalledOnValidThread() to verify.
michael@0: //
michael@0: // This is intended to be used with classes that appear to be thread safe, but
michael@0: // aren't.  For example, a service or a singleton like the preferences system.
michael@0: //
michael@0: // Example:
michael@0: // class MyClass : public NonThreadSafe {
michael@0: //  public:
michael@0: //   void Foo() {
michael@0: //     DCHECK(CalledOnValidThread());
michael@0: //     ... (do stuff) ...
michael@0: //   }
michael@0: // }
michael@0: //
michael@0: // In Release mode, CalledOnValidThread will always return true.
michael@0: //
michael@0: #ifndef NDEBUG
michael@0: class NonThreadSafe {
michael@0:  public:
michael@0:   NonThreadSafe();
michael@0:   ~NonThreadSafe();
michael@0: 
michael@0:   bool CalledOnValidThread() const;
michael@0: 
michael@0:  private:
michael@0:   PlatformThreadId valid_thread_id_;
michael@0: };
michael@0: #else
michael@0: // Do nothing in release mode.
michael@0: class NonThreadSafe {
michael@0:  public:
michael@0:   NonThreadSafe() {}
michael@0:   ~NonThreadSafe() {}
michael@0: 
michael@0:   bool CalledOnValidThread() const {
michael@0:     return true;
michael@0:   }
michael@0: };
michael@0: #endif  // NDEBUG
michael@0: 
michael@0: #endif  // BASE_NON_THREAD_SAFE_H__