cef/include/base/internal/cef_lock_impl.h

// Copyright (c) 2011 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.
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// Framework nor the names of its contributors may be used to endorse
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// written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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// Do not include this header file directly. Use base/cef_lock.h instead.

#ifndef CEF_INCLUDE_BASE_INTERNAL_CEF_LOCK_IMPL_H_
#define CEF_INCLUDE_BASE_INTERNAL_CEF_LOCK_IMPL_H_

#include "include/base/cef_build.h"

#if defined(OS_WIN)
#include <windows.h>
#elif defined(OS_POSIX)
#include <pthread.h>
#endif

namespace base {
namespace cef_internal {

// This class implements the underlying platform-specific spin-lock mechanism
// used for the Lock class.  Most users should not use LockImpl directly, but
// should instead use Lock.
class LockImpl {
 public:
#if defined(OS_WIN)
  typedef CRITICAL_SECTION NativeHandle;
#elif defined(OS_POSIX)
  typedef pthread_mutex_t NativeHandle;
#endif

  LockImpl();

  LockImpl(const LockImpl&) = delete;
  LockImpl& operator=(const LockImpl&) = delete;

  ~LockImpl();

  // If the lock is not held, take it and return true.  If the lock is already
  // held by something else, immediately return false.
  bool Try();

  // Take the lock, blocking until it is available if necessary.
  void Lock();

  // Release the lock.  This must only be called by the lock's holder: after
  // a successful call to Try, or a call to Lock.
  void Unlock();

  // Return the native underlying lock.
  // TODO(awalker): refactor lock and condition variables so that this is
  // unnecessary.
  NativeHandle* native_handle() { return &native_handle_; }

 private:
  NativeHandle native_handle_;
};

}  // namespace cef_internal
}  // namespace base

#endif  // CEF_INCLUDE_BASE_INTERNAL_CEF_LOCK_IMPL_H_