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149 lines
4.2 KiB
149 lines
4.2 KiB
5 months ago
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#ifndef THR_RWLOCK_INCLUDED
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#define THR_RWLOCK_INCLUDED
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/* Copyright (c) 2014, 2017, Oracle and/or its affiliates. All rights reserved.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2.0,
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as published by the Free Software Foundation.
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This program is also distributed with certain software (including
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but not limited to OpenSSL) that is licensed under separate terms,
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as designated in a particular file or component or in included license
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documentation. The authors of MySQL hereby grant you an additional
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permission to link the program and your derivative works with the
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separately licensed software that they have included with MySQL.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License, version 2.0, for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
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/**
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@file include/thr_rwlock.h
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MySQL rwlock implementation.
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There are two "layers":
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1) native_rw_*()
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Functions that map directly down to OS primitives.
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Windows - SRWLock
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Other OSes - pthread
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2) mysql_rw*()
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Functions that include Performance Schema instrumentation.
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See include/mysql/psi/mysql_thread.h
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This file also includes rw_pr_*(), which implements a special
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version of rwlocks that prefer readers. The P_S version of these
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are mysql_prlock_*() - see include/mysql/psi/mysql_thread.h
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*/
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#include <stddef.h>
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#include <sys/types.h>
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#ifdef _WIN32
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#include <windows.h>
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#endif
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#include "my_dbug.h"
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#include "my_inttypes.h"
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#include "my_macros.h"
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#include "my_thread.h"
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#include "mysql/components/services/thr_rwlock_bits.h"
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#include "thr_cond.h"
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#include "thr_mutex.h"
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static inline int native_rw_init(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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InitializeSRWLock(&rwp->srwlock);
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rwp->have_exclusive_srwlock = false;
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return 0;
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#else
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/* pthread_rwlockattr_t is not used in MySQL */
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return pthread_rwlock_init(rwp, NULL);
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#endif
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}
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static inline int native_rw_destroy(
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native_rw_lock_t *rwp MY_ATTRIBUTE((unused))) {
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#ifdef _WIN32
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return 0; /* no destroy function */
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#else
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return pthread_rwlock_destroy(rwp);
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#endif
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}
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static inline int native_rw_rdlock(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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AcquireSRWLockShared(&rwp->srwlock);
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return 0;
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#else
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return pthread_rwlock_rdlock(rwp);
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#endif
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}
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static inline int native_rw_tryrdlock(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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if (!TryAcquireSRWLockShared(&rwp->srwlock)) return EBUSY;
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return 0;
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#else
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return pthread_rwlock_tryrdlock(rwp);
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#endif
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}
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static inline int native_rw_wrlock(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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AcquireSRWLockExclusive(&rwp->srwlock);
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rwp->have_exclusive_srwlock = true;
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return 0;
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#else
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return pthread_rwlock_wrlock(rwp);
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#endif
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}
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static inline int native_rw_trywrlock(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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if (!TryAcquireSRWLockExclusive(&rwp->srwlock)) return EBUSY;
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rwp->have_exclusive_srwlock = true;
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return 0;
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#else
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return pthread_rwlock_trywrlock(rwp);
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#endif
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}
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static inline int native_rw_unlock(native_rw_lock_t *rwp) {
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#ifdef _WIN32
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if (rwp->have_exclusive_srwlock) {
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rwp->have_exclusive_srwlock = false;
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ReleaseSRWLockExclusive(&rwp->srwlock);
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} else
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ReleaseSRWLockShared(&rwp->srwlock);
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return 0;
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#else
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return pthread_rwlock_unlock(rwp);
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#endif
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}
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extern int rw_pr_init(rw_pr_lock_t *);
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extern int rw_pr_rdlock(rw_pr_lock_t *);
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extern int rw_pr_wrlock(rw_pr_lock_t *);
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extern int rw_pr_unlock(rw_pr_lock_t *);
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extern int rw_pr_destroy(rw_pr_lock_t *);
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#ifdef SAFE_MUTEX
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static inline void rw_pr_lock_assert_write_owner(const rw_pr_lock_t *rwlock) {
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DBUG_ASSERT(rwlock->active_writer &&
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my_thread_equal(my_thread_self(), rwlock->writer_thread));
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}
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static inline void rw_pr_lock_assert_not_write_owner(
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const rw_pr_lock_t *rwlock) {
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DBUG_ASSERT(!rwlock->active_writer ||
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!my_thread_equal(my_thread_self(), rwlock->writer_thread));
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}
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#endif
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#endif /* THR_RWLOCK_INCLUDED */
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