// Copyright (c) 2012 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 RLZ_LIB_RECURSIVE_CROSS_PROCESS_LOCK_POSIX_H_ #define RLZ_LIB_RECURSIVE_CROSS_PROCESS_LOCK_POSIX_H_ #include namespace base { class FilePath; } namespace rlz_lib { // Creating a recursive cross-process mutex on Windows is one line. On POSIX, // there's no primitive for that, so this lock is emulated by an in-process // mutex to get the recursive part, followed by a cross-process lock for the // cross-process part. // This is a struct so that it doesn't need a static initializer. struct RecursiveCrossProcessLock { // Tries to acquire a recursive cross-process lock. Note that this _always_ // acquires the in-process lock (if it wasn't already acquired). The parent // directory of |lock_file| must exist. bool TryGetCrossProcessLock(const base::FilePath& lock_filename); // Releases the lock. Should always be called, even if // TryGetCrossProcessLock() returned |false|. void ReleaseLock(); pthread_mutex_t recursive_lock_; pthread_t locking_thread_; int file_lock_; }; // On Mac, PTHREAD_RECURSIVE_MUTEX_INITIALIZER doesn't exist before 10.7 and // is buggy on 10.7 (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51906#c34), // so emulate recursive locking with a normal non-recursive mutex. #define RECURSIVE_CROSS_PROCESS_LOCK_INITIALIZER \ { PTHREAD_MUTEX_INITIALIZER, 0, -1 } } // namespace rlz_lib #endif // RLZ_LIB_RECURSIVE_CROSS_PROCESS_LOCK_POSIX_H_