mirror of https://gitee.com/bigwinds/arangodb
512 lines
17 KiB
C++
512 lines
17 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// @brief mutexes, locks and condition variables in posix
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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 2014 ArangoDB GmbH, Cologne, Germany
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/// Copyright 2004-2014 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 ArangoDB GmbH, Cologne, Germany
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///
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/// @author Dr. Frank Celler
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/// @author Copyright 2014, ArangoDB GmbH, Cologne, Germany
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/// @author Copyright 2011-2013, triAGENS GmbH, Cologne, Germany
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////////////////////////////////////////////////////////////////////////////////
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#include "locks.h"
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#ifdef TRI_HAVE_POSIX_THREADS
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#include "Basics/logging.h"
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// -----------------------------------------------------------------------------
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// --SECTION-- DEFINES
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- private macros
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief busy wait delay (in microseconds)
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///
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/// busy waiting is used if we cannot acquire a read-lock on a shared read/write
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/// in case of too many concurrent lock requests. we'll wait in a busy
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/// loop until we can acquire the lock
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////////////////////////////////////////////////////////////////////////////////
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#define BUSY_LOCK_DELAY (10 * 1000)
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// -----------------------------------------------------------------------------
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// --SECTION-- MUTEX
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialises a new mutex
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////////////////////////////////////////////////////////////////////////////////
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int TRI_InitMutex (TRI_mutex_t* mutex) {
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return pthread_mutex_init(mutex, 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroys a mutex
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////////////////////////////////////////////////////////////////////////////////
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int TRI_DestroyMutex (TRI_mutex_t* mutex) {
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return pthread_mutex_destroy(mutex);
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief locks mutex
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////////////////////////////////////////////////////////////////////////////////
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void TRI_LockMutex (TRI_mutex_t* mutex) {
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int rc;
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rc = pthread_mutex_lock(mutex);
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if (rc != 0) {
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if (rc == EDEADLK) {
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LOG_ERROR("mutex deadlock detected");
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}
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LOG_FATAL_AND_EXIT("could not lock the mutex: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief unlocks mutex
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////////////////////////////////////////////////////////////////////////////////
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void TRI_UnlockMutex (TRI_mutex_t* mutex) {
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int rc;
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rc = pthread_mutex_unlock(mutex);
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if (rc != 0) {
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LOG_FATAL_AND_EXIT("could not release the mutex: %s", strerror(rc));
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}
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- SPIN
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// -----------------------------------------------------------------------------
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#ifndef TRI_FAKE_SPIN_LOCKS
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#ifdef TRI_HAVE_POSIX_SPIN
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialises a new spin-lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_InitSpin (TRI_spin_t* spinLock) {
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pthread_spin_init(spinLock, 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroys a spin-lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_DestroySpin (TRI_spin_t* spinLock) {
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pthread_spin_destroy(spinLock);
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief locks spin-lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_LockSpin (TRI_spin_t* spinLock) {
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int rc;
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rc = pthread_spin_lock(spinLock);
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if (rc != 0) {
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if (rc == EDEADLK) {
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LOG_ERROR("spinlock deadlock detected");
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}
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not lock the spin-lock: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief unlocks spin-lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_UnlockSpin (TRI_spin_t* spinLock) {
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int rc;
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rc = pthread_spin_unlock(spinLock);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not release the spin-lock: %s", strerror(rc));
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}
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}
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#endif
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#endif
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// -----------------------------------------------------------------------------
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// --SECTION-- READ-WRITE LOCK
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialises a new read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_InitReadWriteLock (TRI_read_write_lock_t* lock) {
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pthread_rwlock_init(lock, 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroys a read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_DestroyReadWriteLock (TRI_read_write_lock_t* lock) {
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pthread_rwlock_destroy(lock);
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief tries to read lock read-write lock
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////////////////////////////////////////////////////////////////////////////////
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bool TRI_TryReadLockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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rc = pthread_rwlock_tryrdlock(lock);
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return (rc == 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief read locks read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_ReadLockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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bool complained = false;
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again:
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rc = pthread_rwlock_rdlock(lock);
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if (rc != 0) {
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if (rc == EAGAIN) {
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// use busy waiting if we cannot acquire the read-lock in case of too many
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// concurrent read locks ("resource temporarily unavailable").
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// in this case we'll wait in a busy loop until we can acquire the lock
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if (! complained) {
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LOG_WARNING("too many read-locks on read-write lock");
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complained = true;
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}
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usleep(BUSY_LOCK_DELAY);
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#ifdef TRI_HAVE_SCHED_H
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// let other threads do things
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sched_yield();
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#endif
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// ideal use case for goto :-)
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goto again;
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}
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if (rc == EDEADLK) {
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LOG_ERROR("rw-lock deadlock detected");
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}
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not read-lock the read-write lock: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief read unlocks read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_ReadUnlockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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rc = pthread_rwlock_unlock(lock);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not read-unlock the read-write lock: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief tries to write lock read-write lock
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////////////////////////////////////////////////////////////////////////////////
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bool TRI_TryWriteLockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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rc = pthread_rwlock_trywrlock(lock);
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return (rc == 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief write locks read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_WriteLockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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rc = pthread_rwlock_wrlock(lock);
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if (rc != 0) {
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if (rc == EDEADLK) {
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LOG_ERROR("rw-lock deadlock detected");
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}
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not write-lock the read-write lock: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief write unlocks read-write lock
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////////////////////////////////////////////////////////////////////////////////
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void TRI_WriteUnlockReadWriteLock (TRI_read_write_lock_t* lock) {
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int rc;
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rc = pthread_rwlock_unlock(lock);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not write-unlock the read-write lock: %s", strerror(rc));
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}
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- CONDITION VARIABLE
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// -----------------------------------------------------------------------------
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// -----------------------------------------------------------------------------
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// --SECTION-- constructors and destructors
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initialises a new condition variable
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////////////////////////////////////////////////////////////////////////////////
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void TRI_InitCondition (TRI_condition_t* cond) {
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pthread_cond_init(&cond->_cond, 0);
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cond->_mutex = static_cast<pthread_mutex_t*>(TRI_Allocate(TRI_CORE_MEM_ZONE, sizeof(pthread_mutex_t), false));
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if (cond->_mutex == NULL) {
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LOG_FATAL_AND_EXIT("could not allocate memory for condition variable mutex");
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}
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pthread_mutex_init(cond->_mutex, 0);
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroys a condition variable
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////////////////////////////////////////////////////////////////////////////////
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void TRI_DestroyCondition (TRI_condition_t* cond) {
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pthread_cond_destroy(&cond->_cond);
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pthread_mutex_destroy(cond->_mutex);
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TRI_Free(TRI_CORE_MEM_ZONE, cond->_mutex);
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}
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// -----------------------------------------------------------------------------
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// --SECTION-- public functions
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// -----------------------------------------------------------------------------
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////////////////////////////////////////////////////////////////////////////////
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/// @brief signals a condition variable
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///
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/// Note that you must hold the lock.
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////////////////////////////////////////////////////////////////////////////////
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void TRI_SignalCondition (TRI_condition_t* cond) {
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int rc;
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rc = pthread_cond_signal(&cond->_cond);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not signal the condition: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief broad casts a condition variable
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///
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/// Note that you must hold the lock.
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////////////////////////////////////////////////////////////////////////////////
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void TRI_BroadcastCondition (TRI_condition_t* cond) {
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int rc;
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rc = pthread_cond_broadcast(&cond->_cond);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not croadcast the condition: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief waits for a signal on a condition variable
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///
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/// Note that you must hold the lock.
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////////////////////////////////////////////////////////////////////////////////
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void TRI_WaitCondition (TRI_condition_t* cond) {
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int rc;
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rc = pthread_cond_wait(&cond->_cond, cond->_mutex);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not wait for the condition: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief waits for a signal with a timeout in micro-seconds
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///
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/// Note that you must hold the lock.
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////////////////////////////////////////////////////////////////////////////////
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bool TRI_TimedWaitCondition (TRI_condition_t* cond, uint64_t delay) {
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int rc;
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struct timespec ts;
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struct timeval tp;
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uint64_t x, y;
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if (gettimeofday(&tp, NULL) != 0) {
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LOG_FATAL_AND_EXIT("could not get time of day");
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}
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// Convert from timeval to timespec
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ts.tv_sec = tp.tv_sec;
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x = (tp.tv_usec * 1000) + (delay * 1000);
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y = (x % 1000000000);
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ts.tv_nsec = y;
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ts.tv_sec = ts.tv_sec + ((x - y) / 1000000000);
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// and wait
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rc = pthread_cond_timedwait(&cond->_cond, cond->_mutex, &ts);
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if (rc != 0) {
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if (rc == ETIMEDOUT) {
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return false;
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}
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not wait for the condition: %s", strerror(rc));
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}
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return true;
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief locks the mutex of a condition variable
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////////////////////////////////////////////////////////////////////////////////
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void TRI_LockCondition (TRI_condition_t* cond) {
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int rc;
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rc = pthread_mutex_lock(cond->_mutex);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not lock the condition: %s", strerror(rc));
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}
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}
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////////////////////////////////////////////////////////////////////////////////
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/// @brief unlocks the mutex of a condition variable
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////////////////////////////////////////////////////////////////////////////////
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void TRI_UnlockCondition (TRI_condition_t* cond) {
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int rc;
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rc = pthread_mutex_unlock(cond->_mutex);
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if (rc != 0) {
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#ifdef TRI_ENABLE_MAINTAINER_MODE
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TRI_ASSERT(false);
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#endif
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LOG_FATAL_AND_EXIT("could not unlock the condition: %s", strerror(rc));
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}
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}
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#endif
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// -----------------------------------------------------------------------------
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// --SECTION-- END-OF-FILE
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// -----------------------------------------------------------------------------
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// Local Variables:
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// mode: outline-minor
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// outline-regexp: "/// @brief\\|/// {@inheritDoc}\\|/// @page\\|// --SECTION--\\|/// @\\}"
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// End:
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