mirror of https://gitee.com/bigwinds/arangodb
148 lines
3.3 KiB
C++
148 lines
3.3 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// @brief Read-Write Lock
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///
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/// @file
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///
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/// DISCLAIMER
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///
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/// Copyright 2010-2011 triagens GmbH, Cologne, Germany
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is triAGENS GmbH, Cologne, Germany
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///
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/// @author Frank Celler
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/// @author Achim Brandt
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/// @author Copyright 2010-2011, triAGENS GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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#include "ReadWriteLock-posix.h"
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#include <Basics/Logger.h>
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namespace triagens {
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namespace basics {
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// -----------------------------------------------------------------------------
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// constructors and destructora
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// -----------------------------------------------------------------------------
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ReadWriteLock::ReadWriteLock () {
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int rc = pthread_rwlock_init(&_rwlock, 0);
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if (rc != 0) {
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LOGGER_ERROR << "pthread_rwlock_init() != 0: " << strerror(rc);
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}
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#ifdef READ_WRITE_LOCK_COUNTER
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pthread_mutex_init(&_mutex, 0);
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_readLocked = 0;
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_writeLocked = 0;
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#endif
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}
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ReadWriteLock::~ReadWriteLock () {
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int rc = pthread_rwlock_destroy(&_rwlock);
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if (rc != 0) {
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LOGGER_ERROR << "pthread_rwlock_destroy() != 0: " << strerror(rc);
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}
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#ifdef READ_WRITE_LOCK_COUNTER
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pthread_mutex_destroy(&_mutex);
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#endif
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}
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// -----------------------------------------------------------------------------
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// public methods
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// -----------------------------------------------------------------------------
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bool ReadWriteLock::readLock () {
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int rc = pthread_rwlock_rdlock(&_rwlock);
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if (rc != 0) {
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LOGGER_ERROR << "could not lock for reading: " << strerror(rc);
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return false;
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}
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#ifdef READ_WRITE_LOCK_COUNTER
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{
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pthread_mutex_lock(&_mutex);
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_readLocked++;
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pthread_mutex_unlock(&_mutex);
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}
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#endif
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return true;
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}
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bool ReadWriteLock::writeLock () {
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int rc = pthread_rwlock_wrlock(&_rwlock);
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if (rc != 0) {
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LOGGER_ERROR << "could not lock for writing: " << strerror(rc);
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return false;
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}
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#ifdef READ_WRITE_LOCK_COUNTER
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{
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pthread_mutex_lock(&_mutex);
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_writeLocked++;
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pthread_mutex_unlock(&_mutex);
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}
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#endif
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return true;
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}
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bool ReadWriteLock::unlock () {
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#ifdef READ_WRITE_LOCK_COUNTER
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{
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pthread_mutex_lock(&_mutex);
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if (_writeLocked > 0) {
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_writeLocked--;
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}
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else {
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_readLocked--;
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}
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pthread_mutex_unlock(&_mutex);
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}
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#endif
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int rc = pthread_rwlock_unlock(&_rwlock);
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if (rc != 0) {
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LOGGER_ERROR << "could not release lock: " << strerror(rc);
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return false;
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}
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return true;
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}
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}
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}
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