// Copyright (c) 2014 Marshall A. Greenblatt. Portions copyright (c) 2012
// Google Inc. All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//    * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
//    * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
//    * Neither the name of Google Inc. nor the name Chromium Embedded
// Framework nor the names of its contributors may be used to endorse
// or promote products derived from this software without specific prior
// written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

#ifndef BASE_THREAD_THREAD_CHECKER_H_
#define BASE_THREAD_THREAD_CHECKER_H_

// The following is substantially similar to the Chromium implementation.
// If the Chromium implementation diverges the below implementation should be
// updated to match.

#include "base/debug/logging.h"
#include "base/memory/lock.h"

#include <thread>

namespace base {

namespace internal {

///
/// Do nothing implementation, for use in release mode.
///
/// Note: You should almost always use the ThreadChecker class to get the
/// right version for your build configuration.
///
class ThreadCheckerDoNothing {
 public:
  bool CalledOnValidThread() const { return true; }

  void DetachFromThread() {}
};

class ThreadCheckerImpl {
 public:
  ThreadCheckerImpl();
  ~ThreadCheckerImpl();

  bool CalledOnValidThread() const;

  // Changes the thread that is checked for in CalledOnValidThread.  This may
  // be useful when an object may be created on one thread and then used
  // exclusively on another thread.
  void DetachFromThread();

 private:
  void EnsureThreadIdAssigned() const;

  mutable base::Lock lock_;
  // This is mutable so that CalledOnValidThread can set it.
  // It's guarded by |lock_|.
  mutable std::thread::id valid_thread_id_;
};

}  // namespace internal

class ThreadChecker : public internal::ThreadCheckerDoNothing {};

}  // namespace base

#endif  // BASE_THREAD_THREAD_CHECKER_H_
