15821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Copyright (c) 2012 The Chromium Authors. All rights reserved. 25821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// Use of this source code is governed by a BSD-style license that can be 35821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)// found in the LICENSE file. 45821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 5a1401311d1ab56c4ed0a474bd38c108f75cb0cd9Torne (Richard Coles)#include "net/disk_cache/blockfile/file_lock.h" 65821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 75821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#include "base/atomicops.h" 85821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 95821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace { 105821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 115821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void Barrier() { 125821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#if !defined(COMPILER_MSVC) 135821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) // VS uses memory barrier semantics for volatiles. 145821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) base::subtle::MemoryBarrier(); 155821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)#endif 165821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 175821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 185821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace 195821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 205821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)namespace disk_cache { 215821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 225821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)FileLock::FileLock(BlockFileHeader* header) { 235821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) updating_ = &header->updating; 245821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (*updating_)++; 255821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Barrier(); 265821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) acquired_ = true; 275821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 285821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 295821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)FileLock::~FileLock() { 305821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Unlock(); 315821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 325821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 335821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void FileLock::Lock() { 345821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (acquired_) 355821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 365821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (*updating_)++; 375821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Barrier(); 385821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 395821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 405821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)void FileLock::Unlock() { 415821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) if (!acquired_) 425821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) return; 435821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) Barrier(); 445821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) (*updating_)--; 455821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} 465821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles) 475821806d5e7f356e8fa4b058a389a808ea183019Torne (Richard Coles)} // namespace disk_cache 48