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/*
* Copyright (c) 2008-2014 Travis Geiselbrecht
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files
* (the "Software"), to deal in the Software without restriction,
* including without limitation the rights to use, copy, modify, merge,
* publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so,
* subject to the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef __KERNEL_EVENT_H
#define __KERNEL_EVENT_H
#include <compiler.h>
#include <stdbool.h>
#include <sys/types.h>
#include <kernel/thread.h>
__BEGIN_CDECLS;
#define EVENT_MAGIC (0x65766E74) // "evnt"
typedef struct event {
int magic;
bool signalled;
uint flags;
wait_queue_t wait;
} event_t;
#define EVENT_FLAG_AUTOUNSIGNAL 1
#define EVENT_INITIAL_VALUE(e, initial, _flags) \
{ \
.magic = EVENT_MAGIC, \
.signalled = initial, \
.flags = _flags, \
.wait = WAIT_QUEUE_INITIAL_VALUE((e).wait), \
}
/* Rules for Events:
* - Events may be signaled from interrupt context *but* the reschedule
* parameter must be false in that case.
* - Events may not be waited upon from interrupt context.
* - Events without FLAG_AUTOUNSIGNAL:
* - Wake up any waiting threads when signaled.
* - Continue to do so (no threads will wait) until unsignaled.
* - Events with FLAG_AUTOUNSIGNAL:
* - If one or more threads are waiting when signaled, one thread will
* be woken up and return. The signaled state will not be set.
* - If no threads are waiting when signaled, the Event will remain
* in the signaled state until a thread attempts to wait (at which
* time it will unsignal atomicly and return immediately) or
* event_unsignal() is called.
*/
void event_init(event_t *, bool initial, uint flags);
void event_destroy(event_t *);
status_t event_wait_timeout(event_t *, lk_time_t); /* wait on the event with a timeout */
status_t event_signal(event_t *, bool reschedule);
status_t event_unsignal(event_t *);
static inline bool event_initialized(event_t *e)
{
return e->magic == EVENT_MAGIC;
}
static inline status_t event_wait(event_t *e)
{
return event_wait_timeout(e, INFINITE_TIME);
}
__END_CDECLS;
#endif
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