michael@0: // Copyright (c) 2011 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_SYNCHRONIZATION_LOCK_IMPL_H_
michael@0: #define BASE_SYNCHRONIZATION_LOCK_IMPL_H_
michael@0: 
michael@0: #include "build/build_config.h"
michael@0: 
michael@0: #if defined(OS_WIN)
michael@0: #include <windows.h>
michael@0: #elif defined(OS_POSIX)
michael@0: #include <pthread.h>
michael@0: #endif
michael@0: 
michael@0: #include "base/base_export.h"
michael@0: #include "base/basictypes.h"
michael@0: 
michael@0: namespace base {
michael@0: namespace internal {
michael@0: 
michael@0: // This class implements the underlying platform-specific spin-lock mechanism
michael@0: // used for the Lock class.  Most users should not use LockImpl directly, but
michael@0: // should instead use Lock.
michael@0: class BASE_EXPORT LockImpl {
michael@0:  public:
michael@0: #if defined(OS_WIN)
michael@0:   typedef CRITICAL_SECTION NativeHandle;
michael@0: #elif defined(OS_POSIX)
michael@0:   typedef pthread_mutex_t NativeHandle;
michael@0: #endif
michael@0: 
michael@0:   LockImpl();
michael@0:   ~LockImpl();
michael@0: 
michael@0:   // If the lock is not held, take it and return true.  If the lock is already
michael@0:   // held by something else, immediately return false.
michael@0:   bool Try();
michael@0: 
michael@0:   // Take the lock, blocking until it is available if necessary.
michael@0:   void Lock();
michael@0: 
michael@0:   // Release the lock.  This must only be called by the lock's holder: after
michael@0:   // a successful call to Try, or a call to Lock.
michael@0:   void Unlock();
michael@0: 
michael@0:   // Return the native underlying lock.
michael@0:   // TODO(awalker): refactor lock and condition variables so that this is
michael@0:   // unnecessary.
michael@0:   NativeHandle* native_handle() { return &native_handle_; }
michael@0: 
michael@0:  private:
michael@0:   NativeHandle native_handle_;
michael@0: 
michael@0:   DISALLOW_COPY_AND_ASSIGN(LockImpl);
michael@0: };
michael@0: 
michael@0: }  // namespace internal
michael@0: }  // namespace base
michael@0: 
michael@0: #endif  // BASE_SYNCHRONIZATION_LOCK_IMPL_H_