128 lines
3.3 KiB
C
128 lines
3.3 KiB
C
/* Plain recursive mutexes (native Windows implementation).
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Copyright (C) 2005-2023 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2005.
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Based on GCC's gthr-win32.h. */
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#include <config.h>
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/* Specification. */
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#include "windows-recmutex.h"
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#include <errno.h>
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void
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glwthread_recmutex_init (glwthread_recmutex_t *mutex)
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{
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mutex->owner = 0;
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mutex->depth = 0;
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InitializeCriticalSection (&mutex->lock);
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mutex->guard.done = 1;
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}
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int
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glwthread_recmutex_lock (glwthread_recmutex_t *mutex)
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{
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if (!mutex->guard.done)
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{
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if (InterlockedIncrement (&mutex->guard.started) == 0)
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/* This thread is the first one to need this mutex. Initialize it. */
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glwthread_recmutex_init (mutex);
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else
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{
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/* Don't let mutex->guard.started grow and wrap around. */
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InterlockedDecrement (&mutex->guard.started);
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/* Yield the CPU while waiting for another thread to finish
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initializing this mutex. */
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while (!mutex->guard.done)
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Sleep (0);
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}
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}
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{
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DWORD self = GetCurrentThreadId ();
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if (mutex->owner != self)
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{
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EnterCriticalSection (&mutex->lock);
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mutex->owner = self;
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}
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if (++(mutex->depth) == 0) /* wraparound? */
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{
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mutex->depth--;
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return EAGAIN;
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}
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}
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return 0;
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}
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int
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glwthread_recmutex_trylock (glwthread_recmutex_t *mutex)
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{
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if (!mutex->guard.done)
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{
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if (InterlockedIncrement (&mutex->guard.started) == 0)
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/* This thread is the first one to need this mutex. Initialize it. */
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glwthread_recmutex_init (mutex);
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else
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{
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/* Don't let mutex->guard.started grow and wrap around. */
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InterlockedDecrement (&mutex->guard.started);
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/* Let another thread finish initializing this mutex, and let it also
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lock this mutex. */
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return EBUSY;
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}
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}
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{
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DWORD self = GetCurrentThreadId ();
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if (mutex->owner != self)
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{
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if (!TryEnterCriticalSection (&mutex->lock))
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return EBUSY;
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mutex->owner = self;
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}
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if (++(mutex->depth) == 0) /* wraparound? */
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{
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mutex->depth--;
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return EAGAIN;
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}
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}
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return 0;
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}
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int
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glwthread_recmutex_unlock (glwthread_recmutex_t *mutex)
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{
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if (mutex->owner != GetCurrentThreadId ())
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return EPERM;
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if (mutex->depth == 0)
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return EINVAL;
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if (--(mutex->depth) == 0)
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{
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mutex->owner = 0;
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LeaveCriticalSection (&mutex->lock);
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}
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return 0;
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}
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int
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glwthread_recmutex_destroy (glwthread_recmutex_t *mutex)
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{
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if (mutex->owner != 0)
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return EBUSY;
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DeleteCriticalSection (&mutex->lock);
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mutex->guard.done = 0;
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return 0;
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}
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