mirror of https://github.com/mpv-player/mpv
84 lines
3.5 KiB
C
84 lines
3.5 KiB
C
#pragma once
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#include <stdint.h>
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#include <stdbool.h>
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#include "osdep/threads.h"
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// This is basically a single-shot semaphore, intended as light-weight solution
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// for just making a thread wait for another thread.
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struct mp_waiter {
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// All fields are considered private. Use MP_WAITER_INITIALIZER to init.
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mp_mutex lock;
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mp_cond wakeup;
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bool done;
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uintptr_t value;
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};
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// Initialize a mp_waiter object for use with mp_waiter_*().
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#define MP_WAITER_INITIALIZER { \
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.lock = MP_STATIC_MUTEX_INITIALIZER, \
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.wakeup = MP_STATIC_COND_INITIALIZER, \
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}
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// Block until some other thread calls mp_waiter_wakeup(). The function returns
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// the value argument of that wakeup call. After this, the waiter object must
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// not be used anymore. Although you can reinit it with MP_WAITER_INITIALIZER
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// (then you must make sure nothing calls mp_waiter_wakeup() before this).
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uintptr_t mp_waiter_wait(struct mp_waiter *waiter);
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// Unblock the thread waiting with mp_waiter_wait(), and make it return the
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// provided value. If the other thread did not enter that call yet, it will
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// return immediately once it does (mp_waiter_wakeup() always returns
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// immediately). Calling this more than once is not allowed.
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void mp_waiter_wakeup(struct mp_waiter *waiter, uintptr_t value);
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// Query whether the waiter was woken up. If true, mp_waiter_wait() will return
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// immediately. This is useful if you want to use another way to block and
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// wakeup (in parallel to mp_waiter).
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// You still need to call mp_waiter_wait() to free resources.
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bool mp_waiter_poll(struct mp_waiter *waiter);
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// Basically a binary semaphore that supports signaling the semaphore value to
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// a bunch of other complicated mechanisms (such as wakeup pipes). It was made
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// for aborting I/O and thus has according naming.
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struct mp_cancel;
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struct mp_cancel *mp_cancel_new(void *talloc_ctx);
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// Request abort.
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void mp_cancel_trigger(struct mp_cancel *c);
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// Return whether the caller should abort.
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// For convenience, c==NULL is allowed.
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bool mp_cancel_test(struct mp_cancel *c);
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// Wait until the even is signaled. If the timeout (in seconds) expires, return
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// false. timeout==0 polls, timeout<0 waits forever.
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bool mp_cancel_wait(struct mp_cancel *c, double timeout);
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// Restore original state. (Allows reusing a mp_cancel.)
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void mp_cancel_reset(struct mp_cancel *c);
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// Add a callback to invoke when mp_cancel gets triggered. If it's already
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// triggered, call it from mp_cancel_add_cb() directly. May be called multiple
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// times even if the trigger state changes; not called if it resets. In all
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// cases, this may be called with internal locks held (either in mp_cancel, or
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// other locks held by whoever calls mp_cancel_trigger()).
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// There is only one callback. Create a slave mp_cancel to get a private one.
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void mp_cancel_set_cb(struct mp_cancel *c, void (*cb)(void *ctx), void *ctx);
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// If parent gets triggered, automatically trigger slave. There is only 1
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// parent; setting NULL clears the parent. Freeing slave also automatically
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// ends the parent link, but the parent mp_cancel must remain valid until the
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// slave is manually removed or destroyed. Destroying a mp_cancel that still
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// has slaves is an error.
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void mp_cancel_set_parent(struct mp_cancel *slave, struct mp_cancel *parent);
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// win32 "Event" HANDLE that indicates the current mp_cancel state.
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void *mp_cancel_get_event(struct mp_cancel *c);
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// The FD becomes readable if mp_cancel_test() would return true.
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// Don't actually read from it, just use it for poll().
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int mp_cancel_get_fd(struct mp_cancel *c);
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