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