aboutsummaryrefslogtreecommitdiff
path: root/gnulib/import/windows-recmutex.c
blob: d8087ac132dd34525fdf3c99f9cc6db5fde6c20a (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
/* Plain recursive mutexes (native Windows implementation).
   Copyright (C) 2005-2022 Free Software Foundation, Inc.

   This file is free software: you can redistribute it and/or modify
   it under the terms of the GNU Lesser General Public License as
   published by the Free Software Foundation; either version 2.1 of the
   License, or (at your option) any later version.

   This file 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 Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible <bruno@clisp.org>, 2005.
   Based on GCC's gthr-win32.h.  */

#include <config.h>

/* Specification.  */
#include "windows-recmutex.h"

#include <errno.h>

void
glwthread_recmutex_init (glwthread_recmutex_t *mutex)
{
  mutex->owner = 0;
  mutex->depth = 0;
  InitializeCriticalSection (&mutex->lock);
  mutex->guard.done = 1;
}

int
glwthread_recmutex_lock (glwthread_recmutex_t *mutex)
{
  if (!mutex->guard.done)
    {
      if (InterlockedIncrement (&mutex->guard.started) == 0)
        /* This thread is the first one to need this mutex.  Initialize it.  */
        glwthread_recmutex_init (mutex);
      else
        {
          /* Don't let mutex->guard.started grow and wrap around.  */
          InterlockedDecrement (&mutex->guard.started);
          /* Yield the CPU while waiting for another thread to finish
             initializing this mutex.  */
          while (!mutex->guard.done)
            Sleep (0);
        }
    }
  {
    DWORD self = GetCurrentThreadId ();
    if (mutex->owner != self)
      {
        EnterCriticalSection (&mutex->lock);
        mutex->owner = self;
      }
    if (++(mutex->depth) == 0) /* wraparound? */
      {
        mutex->depth--;
        return EAGAIN;
      }
  }
  return 0;
}

int
glwthread_recmutex_trylock (glwthread_recmutex_t *mutex)
{
  if (!mutex->guard.done)
    {
      if (InterlockedIncrement (&mutex->guard.started) == 0)
        /* This thread is the first one to need this mutex.  Initialize it.  */
        glwthread_recmutex_init (mutex);
      else
        {
          /* Don't let mutex->guard.started grow and wrap around.  */
          InterlockedDecrement (&mutex->guard.started);
          /* Let another thread finish initializing this mutex, and let it also
             lock this mutex.  */
          return EBUSY;
        }
    }
  {
    DWORD self = GetCurrentThreadId ();
    if (mutex->owner != self)
      {
        if (!TryEnterCriticalSection (&mutex->lock))
          return EBUSY;
        mutex->owner = self;
      }
    if (++(mutex->depth) == 0) /* wraparound? */
      {
        mutex->depth--;
        return EAGAIN;
      }
  }
  return 0;
}

int
glwthread_recmutex_unlock (glwthread_recmutex_t *mutex)
{
  if (mutex->owner != GetCurrentThreadId ())
    return EPERM;
  if (mutex->depth == 0)
    return EINVAL;
  if (--(mutex->depth) == 0)
    {
      mutex->owner = 0;
      LeaveCriticalSection (&mutex->lock);
    }
  return 0;
}

int
glwthread_recmutex_destroy (glwthread_recmutex_t *mutex)
{
  if (mutex->owner != 0)
    return EBUSY;
  DeleteCriticalSection (&mutex->lock);
  mutex->guard.done = 0;
  return 0;
}