summaryrefslogtreecommitdiffstats
path: root/gl/windows-recmutex.c
diff options
context:
space:
mode:
Diffstat (limited to 'gl/windows-recmutex.c')
-rw-r--r--gl/windows-recmutex.c127
1 files changed, 127 insertions, 0 deletions
diff --git a/gl/windows-recmutex.c b/gl/windows-recmutex.c
new file mode 100644
index 0000000..a8ce9a0
--- /dev/null
+++ b/gl/windows-recmutex.c
@@ -0,0 +1,127 @@
1/* Plain recursive mutexes (native Windows implementation).
2 Copyright (C) 2005-2023 Free Software Foundation, Inc.
3
4 This file is free software: you can redistribute it and/or modify
5 it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 This file is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public License
15 along with this program. If not, see <https://www.gnu.org/licenses/>. */
16
17/* Written by Bruno Haible <bruno@clisp.org>, 2005.
18 Based on GCC's gthr-win32.h. */
19
20#include <config.h>
21
22/* Specification. */
23#include "windows-recmutex.h"
24
25#include <errno.h>
26
27void
28glwthread_recmutex_init (glwthread_recmutex_t *mutex)
29{
30 mutex->owner = 0;
31 mutex->depth = 0;
32 InitializeCriticalSection (&mutex->lock);
33 mutex->guard.done = 1;
34}
35
36int
37glwthread_recmutex_lock (glwthread_recmutex_t *mutex)
38{
39 if (!mutex->guard.done)
40 {
41 if (InterlockedIncrement (&mutex->guard.started) == 0)
42 /* This thread is the first one to need this mutex. Initialize it. */
43 glwthread_recmutex_init (mutex);
44 else
45 {
46 /* Don't let mutex->guard.started grow and wrap around. */
47 InterlockedDecrement (&mutex->guard.started);
48 /* Yield the CPU while waiting for another thread to finish
49 initializing this mutex. */
50 while (!mutex->guard.done)
51 Sleep (0);
52 }
53 }
54 {
55 DWORD self = GetCurrentThreadId ();
56 if (mutex->owner != self)
57 {
58 EnterCriticalSection (&mutex->lock);
59 mutex->owner = self;
60 }
61 if (++(mutex->depth) == 0) /* wraparound? */
62 {
63 mutex->depth--;
64 return EAGAIN;
65 }
66 }
67 return 0;
68}
69
70int
71glwthread_recmutex_trylock (glwthread_recmutex_t *mutex)
72{
73 if (!mutex->guard.done)
74 {
75 if (InterlockedIncrement (&mutex->guard.started) == 0)
76 /* This thread is the first one to need this mutex. Initialize it. */
77 glwthread_recmutex_init (mutex);
78 else
79 {
80 /* Don't let mutex->guard.started grow and wrap around. */
81 InterlockedDecrement (&mutex->guard.started);
82 /* Let another thread finish initializing this mutex, and let it also
83 lock this mutex. */
84 return EBUSY;
85 }
86 }
87 {
88 DWORD self = GetCurrentThreadId ();
89 if (mutex->owner != self)
90 {
91 if (!TryEnterCriticalSection (&mutex->lock))
92 return EBUSY;
93 mutex->owner = self;
94 }
95 if (++(mutex->depth) == 0) /* wraparound? */
96 {
97 mutex->depth--;
98 return EAGAIN;
99 }
100 }
101 return 0;
102}
103
104int
105glwthread_recmutex_unlock (glwthread_recmutex_t *mutex)
106{
107 if (mutex->owner != GetCurrentThreadId ())
108 return EPERM;
109 if (mutex->depth == 0)
110 return EINVAL;
111 if (--(mutex->depth) == 0)
112 {
113 mutex->owner = 0;
114 LeaveCriticalSection (&mutex->lock);
115 }
116 return 0;
117}
118
119int
120glwthread_recmutex_destroy (glwthread_recmutex_t *mutex)
121{
122 if (mutex->owner != 0)
123 return EBUSY;
124 DeleteCriticalSection (&mutex->lock);
125 mutex->guard.done = 0;
126 return 0;
127}