1/* Copyright (c) 2010, Google Inc. 2 * All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * --- 31 * This file is an internal part spinlock.cc and once.cc 32 * It may not be used directly by code outside of //base. 33 */ 34 35#ifndef BASE_SPINLOCK_INTERNAL_H_ 36#define BASE_SPINLOCK_INTERNAL_H_ 37 38#include <config.h> 39#include "base/basictypes.h" 40#include "base/atomicops.h" 41 42namespace base { 43namespace internal { 44 45// SpinLockWait() waits until it can perform one of several transitions from 46// "from" to "to". It returns when it performs a transition where done==true. 47struct SpinLockWaitTransition { 48 int32 from; 49 int32 to; 50 bool done; 51}; 52 53// Wait until *w can transition from trans[i].from to trans[i].to for some i 54// satisfying 0<=i<n && trans[i].done, atomically make the transition, 55// then return the old value of *w. Make any other atomic tranistions 56// where !trans[i].done, but continue waiting. 57int32 SpinLockWait(volatile Atomic32 *w, int n, 58 const SpinLockWaitTransition trans[]); 59void SpinLockWake(volatile Atomic32 *w, bool all); 60void SpinLockDelay(volatile Atomic32 *w, int32 value, int loop); 61 62} // namespace internal 63} // namespace base 64#endif 65