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DBHomework/mysql_include/thr_mutex.h

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2017-11-19 14:58:43 +08:00
#ifndef THR_MUTEX_INCLUDED
#define THR_MUTEX_INCLUDED
/* Copyright (c) 2014, 2015, 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 as published by
the Free Software Foundation; version 2 of the License.
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 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 */
/**
MySQL mutex implementation.
There are three "layers":
1) native_mutex_*()
Functions that map directly down to OS primitives.
Windows - CriticalSection
Other OSes - pthread
2) my_mutex_*()
Functions that implement SAFE_MUTEX (default for debug),
Otherwise native_mutex_*() is used.
3) mysql_mutex_*()
Functions that include Performance Schema instrumentation.
See include/mysql/psi/mysql_thread.h
*/
#include <my_global.h>
#include "my_thread.h"
C_MODE_START
#ifdef _WIN32
typedef CRITICAL_SECTION native_mutex_t;
typedef int native_mutexattr_t;
#else
typedef pthread_mutex_t native_mutex_t;
typedef pthread_mutexattr_t native_mutexattr_t;
#endif
/* Define mutex types, see my_thr_init.c */
#define MY_MUTEX_INIT_SLOW NULL
/* Can be set in /usr/include/pthread.h */
#ifdef PTHREAD_ADAPTIVE_MUTEX_INITIALIZER_NP
extern native_mutexattr_t my_fast_mutexattr;
#define MY_MUTEX_INIT_FAST &my_fast_mutexattr
#else
#define MY_MUTEX_INIT_FAST NULL
#endif
/* Can be set in /usr/include/pthread.h */
#ifdef PTHREAD_ERRORCHECK_MUTEX_INITIALIZER_NP
extern native_mutexattr_t my_errorcheck_mutexattr;
#define MY_MUTEX_INIT_ERRCHK &my_errorcheck_mutexattr
#else
#define MY_MUTEX_INIT_ERRCHK NULL
#endif
static inline int native_mutex_init(native_mutex_t *mutex,
const native_mutexattr_t *attr)
{
#ifdef _WIN32
InitializeCriticalSection(mutex);
return 0;
#else
return pthread_mutex_init(mutex, attr);
#endif
}
static inline int native_mutex_lock(native_mutex_t *mutex)
{
#ifdef _WIN32
EnterCriticalSection(mutex);
return 0;
#else
return pthread_mutex_lock(mutex);
#endif
}
static inline int native_mutex_trylock(native_mutex_t *mutex)
{
#ifdef _WIN32
if (TryEnterCriticalSection(mutex))
{
/* Don't allow recursive lock */
if (mutex->RecursionCount > 1){
LeaveCriticalSection(mutex);
return EBUSY;
}
return 0;
}
return EBUSY;
#else
return pthread_mutex_trylock(mutex);
#endif
}
static inline int native_mutex_unlock(native_mutex_t *mutex)
{
#ifdef _WIN32
LeaveCriticalSection(mutex);
return 0;
#else
return pthread_mutex_unlock(mutex);
#endif
}
static inline int native_mutex_destroy(native_mutex_t *mutex)
{
#ifdef _WIN32
DeleteCriticalSection(mutex);
return 0;
#else
return pthread_mutex_destroy(mutex);
#endif
}
#ifdef SAFE_MUTEX
/* safe_mutex adds checking to mutex for easier debugging */
typedef struct st_safe_mutex_t
{
native_mutex_t global, mutex;
const char *file;
uint line, count;
my_thread_t thread;
} my_mutex_t;
void safe_mutex_global_init();
int safe_mutex_init(my_mutex_t *mp, const native_mutexattr_t *attr,
const char *file, uint line);
int safe_mutex_lock(my_mutex_t *mp, my_bool try_lock, const char *file, uint line);
int safe_mutex_unlock(my_mutex_t *mp, const char *file, uint line);
int safe_mutex_destroy(my_mutex_t *mp, const char *file, uint line);
static inline void safe_mutex_assert_owner(const my_mutex_t *mp)
{
DBUG_ASSERT(mp->count > 0 &&
my_thread_equal(my_thread_self(), mp->thread));
}
static inline void safe_mutex_assert_not_owner(const my_mutex_t *mp)
{
DBUG_ASSERT(!mp->count ||
!my_thread_equal(my_thread_self(), mp->thread));
}
#else
typedef native_mutex_t my_mutex_t;
#endif
static inline int my_mutex_init(my_mutex_t *mp, const native_mutexattr_t *attr
#ifdef SAFE_MUTEX
, const char *file, uint line
#endif
)
{
#ifdef SAFE_MUTEX
return safe_mutex_init(mp, attr, file, line);
#else
return native_mutex_init(mp, attr);
#endif
}
static inline int my_mutex_lock(my_mutex_t *mp
#ifdef SAFE_MUTEX
, const char *file, uint line
#endif
)
{
#ifdef SAFE_MUTEX
return safe_mutex_lock(mp, FALSE, file, line);
#else
return native_mutex_lock(mp);
#endif
}
static inline int my_mutex_trylock(my_mutex_t *mp
#ifdef SAFE_MUTEX
, const char *file, uint line
#endif
)
{
#ifdef SAFE_MUTEX
return safe_mutex_lock(mp, TRUE, file, line);
#else
return native_mutex_trylock(mp);
#endif
}
static inline int my_mutex_unlock(my_mutex_t *mp
#ifdef SAFE_MUTEX
, const char *file, uint line
#endif
)
{
#ifdef SAFE_MUTEX
return safe_mutex_unlock(mp, file, line);
#else
return native_mutex_unlock(mp);
#endif
}
static inline int my_mutex_destroy(my_mutex_t *mp
#ifdef SAFE_MUTEX
, const char *file, uint line
#endif
)
{
#ifdef SAFE_MUTEX
return safe_mutex_destroy(mp, file, line);
#else
return native_mutex_destroy(mp);
#endif
}
C_MODE_END
#endif /* THR_MUTEX_INCLUDED */