mirror of https://gitee.com/bigwinds/arangodb
190 lines
7.9 KiB
C
190 lines
7.9 KiB
C
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2014-2016 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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////////////////////////////////////////////////////////////////////////////////
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#ifndef ARANGODB_BASICS_LOCKS_H
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#define ARANGODB_BASICS_LOCKS_H 1
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#include "Basics/Common.h"
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#ifdef TRI_HAVE_POSIX_THREADS
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#include "Basics/locks-posix.h"
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#endif
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#ifdef TRI_HAVE_WIN32_THREADS
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#include "Basics/locks-win32.h"
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#endif
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initializes a new mutex
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///
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/// Mutual exclusion (often abbreviated to mutex) algorithms are used in
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/// concurrent programming to avoid the simultaneous use of a common resource,
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/// such as a global variable, by pieces of computer code called critical
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/// sections. A critical section is a piece of code in which a process or thread
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/// accesses a common resource. The critical section by itself is not a
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/// mechanism or algorithm for mutual exclusion. A program, process, or thread
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/// can have the critical section in it without any mechanism or algorithm which
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/// implements mutual exclusion. For details see www.wikipedia.org.
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////////////////////////////////////////////////////////////////////////////////
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int TRI_InitMutex(TRI_mutex_t*);
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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*);
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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*);
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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*);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief initializes a new read-write lock
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///
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/// A ReadWriteLock maintains a pair of associated locks, one for read-only
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/// operations and one for writing. The read lock may be held simultaneously by
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/// multiple reader threads, so long as there are no writers. The write lock is
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/// exclusive.
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///
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/// A read-write lock allows for a greater level of concurrency in accessing
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/// shared data than that permitted by a mutual exclusion lock. It exploits the
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/// fact that while only a single thread at a time (a writer thread) can modify
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/// the shared data, in many cases any number of threads can concurrently read
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/// the data (hence reader threads). In theory, the increase in concurrency
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/// permitted by the use of a read-write lock will lead to performance
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/// improvements over the use of a mutual exclusion lock. In practice this
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/// increase in concurrency will only be fully realized on a multi-processor,
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/// and then only if the access patterns for the shared data are suitable.
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////////////////////////////////////////////////////////////////////////////////
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void TRI_InitReadWriteLock(TRI_read_write_lock_t* lock);
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////////////////////////////////////////////////////////////////////////////////
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/// @brief destroyes 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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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/// @brief initializes a new condition variable
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////////////////////////////////////////////////////////////////////////////////
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void TRI_InitCondition(TRI_condition_t* cond);
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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////////////////////////////////////////////////////////////////////////////////
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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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#endif
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