Commit | Line | Data |
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c0c3707f | 1 | /* Plain recursive mutexes (native Windows implementation). |
5df4cba6 | 2 | Copyright (C) 2005-2020 Free Software Foundation, Inc. |
c0c3707f CB |
3 | |
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 3, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program 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 General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU 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 | ||
27 | void | |
28 | glwthread_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 | ||
36 | int | |
37 | glwthread_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 | ||
70 | int | |
71 | glwthread_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 | ||
104 | int | |
105 | glwthread_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 | ||
119 | int | |
120 | glwthread_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 | } |