mirror of https://github.com/mpv-player/mpv
63 lines
2.2 KiB
C
63 lines
2.2 KiB
C
/* Copyright (C) 2018 the mpv developers
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <assert.h>
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#include <string.h>
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#include "thread_tools.h"
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uintptr_t mp_waiter_wait(struct mp_waiter *waiter)
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{
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pthread_mutex_lock(&waiter->lock);
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while (!waiter->done)
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pthread_cond_wait(&waiter->wakeup, &waiter->lock);
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pthread_mutex_unlock(&waiter->lock);
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uintptr_t ret = waiter->value;
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// We document that after mp_waiter_wait() the waiter object becomes
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// invalid. (It strictly returns only after mp_waiter_wakeup() has returned,
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// and the object is "single-shot".) So destroy it here.
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// Normally, we expect that the system uses futexes, in which case the
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// following functions will do nearly nothing. This is true for Windows
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// and Linux. But some lesser OSes still might allocate kernel objects
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// when initializing mutexes, so destroy them here.
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pthread_mutex_destroy(&waiter->lock);
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pthread_cond_destroy(&waiter->wakeup);
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memset(waiter, 0xCA, sizeof(*waiter)); // for debugging
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return ret;
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}
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void mp_waiter_wakeup(struct mp_waiter *waiter, uintptr_t value)
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{
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pthread_mutex_lock(&waiter->lock);
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assert(!waiter->done);
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waiter->done = true;
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waiter->value = value;
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pthread_cond_signal(&waiter->wakeup);
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pthread_mutex_unlock(&waiter->lock);
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}
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bool mp_waiter_poll(struct mp_waiter *waiter)
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{
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pthread_mutex_lock(&waiter->lock);
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bool r = waiter->done;
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pthread_mutex_unlock(&waiter->lock);
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return r;
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}
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