MySQL 8.4.3
Source Code Documentation
thr_cond.h
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1#ifndef THR_COND_INCLUDED
2#define THR_COND_INCLUDED
3
4/* Copyright (c) 2014, 2024, Oracle and/or its affiliates.
5
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8 as published by the Free Software Foundation.
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15 separately licensed software that they have either included with
16 the program or referenced in the documentation.
17
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19 but WITHOUT ANY WARRANTY; without even the implied warranty of
20 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
21 GNU General Public License, version 2.0, for more details.
22
23 You should have received a copy of the GNU General Public License
24 along with this program; if not, write to the Free Software
25 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */
26
27/**
28 @file include/thr_cond.h
29 MySQL condition variable implementation.
30
31 There are three "layers":
32 1) native_cond_*()
33 Functions that map directly down to OS primitives.
34 Windows - ConditionVariable
35 Other OSes - pthread
36 2) my_cond_*()
37 Functions that use SAFE_MUTEX (default for debug).
38 Otherwise native_cond_*() is used.
39 3) mysql_cond*()
40 Functions that include Performance Schema instrumentation.
41 See include/mysql/psi/mysql_thread.h
42*/
43
44#include <stddef.h>
45#include <sys/types.h>
46#ifdef _WIN32
47#include <time.h>
48#include "my_systime.h"
49#endif
50
51#include "my_macros.h"
52#include "my_thread.h"
54#include "thr_mutex.h"
55
56#ifdef _WIN32
57/**
58 Convert abstime to milliseconds
59*/
60
61static DWORD get_milliseconds(const struct timespec *abstime) {
62 /*
63 Convert timespec to millis and subtract current time.
64 my_getsystime() returns time in 100 ns units.
65 */
66 const ulonglong future = abstime->tv_sec * 1000 + abstime->tv_nsec / 1000000;
67 const ulonglong now = my_getsystime() / 10000;
68 /* Don't allow the timeout to be negative. */
69 if (future < now) return 0;
70 return (DWORD)(future - now);
71}
72#endif /* _WIN32 */
73
74static inline int native_cond_init(native_cond_t *cond) {
75#ifdef _WIN32
76 InitializeConditionVariable(cond);
77 return 0;
78#else
79 /* pthread_condattr_t is not used in MySQL */
80 return pthread_cond_init(cond, nullptr);
81#endif
82}
83
84static inline int native_cond_destroy(native_cond_t *cond [[maybe_unused]]) {
85#ifdef _WIN32
86 return 0; /* no destroy function */
87#else
88 return pthread_cond_destroy(cond);
89#endif
90}
91
92static inline int native_cond_timedwait(native_cond_t *cond,
93 native_mutex_t *mutex,
94 const struct timespec *abstime) {
95#ifdef _WIN32
96 const DWORD timeout = get_milliseconds(abstime);
97 if (!SleepConditionVariableCS(cond, mutex, timeout)) return ETIMEDOUT;
98 return 0;
99#else
100 return pthread_cond_timedwait(cond, mutex, abstime);
101#endif
102}
103
104static inline int native_cond_wait(native_cond_t *cond, native_mutex_t *mutex) {
105#ifdef _WIN32
106 if (!SleepConditionVariableCS(cond, mutex, INFINITE)) return ETIMEDOUT;
107 return 0;
108#else
109 return pthread_cond_wait(cond, mutex);
110#endif
111}
112
113static inline int native_cond_signal(native_cond_t *cond) {
114#ifdef _WIN32
115 WakeConditionVariable(cond);
116 return 0;
117#else
118 return pthread_cond_signal(cond);
119#endif
120}
121
122static inline int native_cond_broadcast(native_cond_t *cond) {
123#ifdef _WIN32
124 WakeAllConditionVariable(cond);
125 return 0;
126#else
127 return pthread_cond_broadcast(cond);
128#endif
129}
130
131#ifdef SAFE_MUTEX
132int safe_cond_wait(native_cond_t *cond, safe_mutex_t *mp, const char *file,
133 uint line);
134int safe_cond_timedwait(native_cond_t *cond, safe_mutex_t *mp,
135 const struct timespec *abstime, const char *file,
136 uint line);
137#endif
138
139static inline int my_cond_timedwait(native_cond_t *cond, my_mutex_t *mp,
140 const struct timespec *abstime
141#ifdef SAFE_MUTEX
142 ,
143 const char *file, uint line
144#endif
145) {
146#ifdef SAFE_MUTEX
147 return safe_cond_timedwait(cond, mp->m_u.m_safe_ptr, abstime, file, line);
148#else
149 return native_cond_timedwait(cond, &mp->m_u.m_native, abstime);
150#endif
151}
152
153static inline int my_cond_wait(native_cond_t *cond, my_mutex_t *mp
154#ifdef SAFE_MUTEX
155 ,
156 const char *file, uint line
157#endif
158) {
159#ifdef SAFE_MUTEX
160 return safe_cond_wait(cond, mp->m_u.m_safe_ptr, file, line);
161#else
162 return native_cond_wait(cond, &mp->m_u.m_native);
163#endif
164}
165
166#endif /* THR_COND_INCLUDED */
unsigned long long int ulonglong
Definition: my_inttypes.h:56
Some common macros.
Defines for getting and processing the current system type programmatically.
unsigned long long int my_getsystime()
Get high-resolution time.
Definition: my_systime.h:102
Defines to make different thread packages compatible.
#define ETIMEDOUT
Definition: my_thread.h:48
Definition: os0file.h:89
static bool timeout(bool(*wait_condition)())
Timeout function.
Definition: log0meb.cc:498
Definition: thr_mutex_bits.h:61
union my_mutex_t::u m_u
static int native_cond_init(native_cond_t *cond)
Definition: thr_cond.h:74
static int native_cond_wait(native_cond_t *cond, native_mutex_t *mutex)
Definition: thr_cond.h:104
static int native_cond_broadcast(native_cond_t *cond)
Definition: thr_cond.h:122
static int my_cond_timedwait(native_cond_t *cond, my_mutex_t *mp, const struct timespec *abstime)
Definition: thr_cond.h:139
static int my_cond_wait(native_cond_t *cond, my_mutex_t *mp)
Definition: thr_cond.h:153
static int native_cond_destroy(native_cond_t *cond)
Definition: thr_cond.h:84
static int native_cond_signal(native_cond_t *cond)
Definition: thr_cond.h:113
static int native_cond_timedwait(native_cond_t *cond, native_mutex_t *mutex, const struct timespec *abstime)
Definition: thr_cond.h:92
MySQL condition variable implementation.
pthread_cond_t native_cond_t
Definition: thr_cond_bits.h:46
MySQL mutex implementation.
pthread_mutex_t native_mutex_t
Definition: thr_mutex_bits.h:55
Include file for Sun RPC to compile out of the box.
native_mutex_t m_native
Definition: thr_mutex_bits.h:63
safe_mutex_t * m_safe_ptr
Definition: thr_mutex_bits.h:64