text: // Copyright (c) 2011 The Chromium Authors. All rights reserved.
  // Use of this source code is governed by a BSD-style license that can be
  // found in the LICENSE file.
  
  #ifndef BASE_THREADING_THREAD_CHECKER_IMPL_H_
  #define BASE_THREADING_THREAD_CHECKER_IMPL_H_
  
  #include "butil/base_export.h"
  #include "butil/synchronization/lock.h"
  #include "butil/threading/platform_thread.h"
  
  namespace butil {
  
  // Real implementation of ThreadChecker, for use in debug mode, or
  // for temporary use in release mode (e.g. to CHECK on a threading issue
  // seen only in the wild).
  //
  // Note: You should almost always use the ThreadChecker class to get the
  // right version for your build configuration.
  class BASE_EXPORT 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 butil::Lock lock_;
    // This is mutable so that CalledOnValidThread can set it.
    // It's guarded by |lock_|.
    mutable PlatformThreadRef valid_thread_id_;
  };
  
  }  // namespace butil
  
  #endif  // BASE_THREADING_THREAD_CHECKER_IMPL_H_
  