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Diffstat (limited to 'mysql/thr_cond.h')
| -rw-r--r-- | mysql/thr_cond.h | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/mysql/thr_cond.h b/mysql/thr_cond.h new file mode 100644 index 0000000..95df29d --- /dev/null +++ b/mysql/thr_cond.h @@ -0,0 +1,201 @@ +#ifndef THR_COND_INCLUDED +#define THR_COND_INCLUDED + +/* Copyright (c) 2014, 2016, 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 condition variable implementation. + + There are three "layers": + 1) native_cond_*() + Functions that map directly down to OS primitives. + Windows - ConditionVariable + Other OSes - pthread + 2) my_cond_*() + Functions that use SAFE_MUTEX (default for debug). + Otherwise native_cond_*() is used. + 3) mysql_cond*() + Functions that include Performance Schema instrumentation. + See include/mysql/psi/mysql_thread.h +*/ + +#include "my_thread.h" +#include "thr_mutex.h" + +C_MODE_START + +#ifdef _WIN32 +typedef CONDITION_VARIABLE native_cond_t; +#else +typedef pthread_cond_t native_cond_t; +#endif + +#ifdef _WIN32 +/** + Convert abstime to milliseconds +*/ + +static DWORD get_milliseconds(const struct timespec *abstime) +{ +#ifndef HAVE_STRUCT_TIMESPEC + long long millis; + union ft64 now; + + if (abstime == NULL) + return INFINITE; + + GetSystemTimeAsFileTime(&now.ft); + + /* + Calculate time left to abstime + - subtract start time from current time(values are in 100ns units) + - convert to millisec by dividing with 10000 + */ + millis= (abstime->tv.i64 - now.i64) / 10000; + + /* Don't allow the timeout to be negative */ + if (millis < 0) + return 0; + + /* + Make sure the calculated timeout does not exceed original timeout + value which could cause "wait for ever" if system time changes + */ + if (millis > abstime->max_timeout_msec) + millis= abstime->max_timeout_msec; + + if (millis > UINT_MAX) + millis= UINT_MAX; + + return (DWORD)millis; +#else + /* + Convert timespec to millis and subtract current time. + my_getsystime() returns time in 100 ns units. + */ + ulonglong future= abstime->tv_sec * 1000 + abstime->tv_nsec / 1000000; + ulonglong now= my_getsystime() / 10000; + /* Don't allow the timeout to be negative. */ + if (future < now) + return 0; + return (DWORD)(future - now); +#endif +} +#endif /* _WIN32 */ + +static inline int native_cond_init(native_cond_t *cond) +{ +#ifdef _WIN32 + InitializeConditionVariable(cond); + return 0; +#else + /* pthread_condattr_t is not used in MySQL */ + return pthread_cond_init(cond, NULL); +#endif +} + +static inline int native_cond_destroy(native_cond_t *cond) +{ +#ifdef _WIN32 + return 0; /* no destroy function */ +#else + return pthread_cond_destroy(cond); +#endif +} + +static inline int native_cond_timedwait(native_cond_t *cond, + native_mutex_t *mutex, + const struct timespec *abstime) +{ +#ifdef _WIN32 + DWORD timeout= get_milliseconds(abstime); + if (!SleepConditionVariableCS(cond, mutex, timeout)) + return ETIMEDOUT; + return 0; +#else + return pthread_cond_timedwait(cond, mutex, abstime); +#endif +} + +static inline int native_cond_wait(native_cond_t *cond, native_mutex_t *mutex) +{ +#ifdef _WIN32 + if (!SleepConditionVariableCS(cond, mutex, INFINITE)) + return ETIMEDOUT; + return 0; +#else + return pthread_cond_wait(cond, mutex); +#endif +} + +static inline int native_cond_signal(native_cond_t *cond) +{ +#ifdef _WIN32 + WakeConditionVariable(cond); + return 0; +#else + return pthread_cond_signal(cond); +#endif +} + +static inline int native_cond_broadcast(native_cond_t *cond) +{ +#ifdef _WIN32 + WakeAllConditionVariable(cond); + return 0; +#else + return pthread_cond_broadcast(cond); +#endif +} + +#ifdef SAFE_MUTEX +int safe_cond_wait(native_cond_t *cond, my_mutex_t *mp, + const char *file, uint line); +int safe_cond_timedwait(native_cond_t *cond, my_mutex_t *mp, + const struct timespec *abstime, + const char *file, uint line); +#endif + +static inline int my_cond_timedwait(native_cond_t *cond, my_mutex_t *mp, + const struct timespec *abstime +#ifdef SAFE_MUTEX + , const char *file, uint line +#endif + ) +{ +#ifdef SAFE_MUTEX + return safe_cond_timedwait(cond, mp, abstime, file, line); +#else + return native_cond_timedwait(cond, mp, abstime); +#endif +} + +static inline int my_cond_wait(native_cond_t *cond, my_mutex_t *mp +#ifdef SAFE_MUTEX + , const char *file, uint line +#endif + ) +{ +#ifdef SAFE_MUTEX + return safe_cond_wait(cond, mp, file, line); +#else + return native_cond_wait(cond, mp); +#endif +} + +C_MODE_END + +#endif /* THR_COND_INCLUDED */ |