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/*
* libusb synchronization on Microsoft Windows
*
* Copyright (C) 2010 Michael Plante <michael.plante@gmail.com>
*
* This library 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 library 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 library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <config.h>
#include <objbase.h>
#include <errno.h>
#include <stdarg.h>
#include "libusbi.h"
int usbi_mutex_init(usbi_mutex_t *mutex,
const usbi_mutexattr_t *attr) {
if(! mutex) return ((errno=EINVAL));
*mutex = CreateMutex(NULL, FALSE, NULL);
if(!*mutex) return ((errno=ENOMEM));
return 0;
}
int usbi_mutex_destroy(usbi_mutex_t *mutex) {
// It is not clear if CloseHandle failure is due to failure to unlock.
// If so, this should be errno=EBUSY.
if(!mutex || !CloseHandle(*mutex)) return ((errno=EINVAL));
*mutex = NULL;
return 0;
}
int usbi_mutex_trylock(usbi_mutex_t *mutex) {
DWORD result;
if(!mutex) return ((errno=EINVAL));
result = WaitForSingleObject(*mutex, 0);
if(result == WAIT_OBJECT_0 || result == WAIT_ABANDONED)
return 0; // acquired (ToDo: check that abandoned is ok)
if(result == WAIT_TIMEOUT)
return ((errno=EBUSY));
return ((errno=EINVAL)); // don't know how this would happen
// so don't know proper errno
}
int usbi_mutex_lock(usbi_mutex_t *mutex) {
DWORD result;
if(!mutex) return ((errno=EINVAL));
result = WaitForSingleObject(*mutex, INFINITE);
if(result == WAIT_OBJECT_0 || result == WAIT_ABANDONED)
return 0; // acquired (ToDo: check that abandoned is ok)
return ((errno=EINVAL)); // don't know how this would happen
// so don't know proper errno
}
int usbi_mutex_unlock(usbi_mutex_t *mutex) {
if(!mutex) return ((errno=EINVAL));
if(!ReleaseMutex(*mutex)) return ((errno=EPERM ));
return 0;
}
int usbi_mutex_static_lock(usbi_mutex_static_t *mutex) {
if(!mutex) return ((errno=EINVAL));
while (InterlockedExchange((LONG *)mutex, 1) == 1) {
SleepEx(0, TRUE);
}
return 0;
}
int usbi_mutex_static_unlock(usbi_mutex_static_t *mutex) {
if(!mutex) return ((errno=EINVAL));
*mutex = 0;
return 0;
}
int usbi_cond_init(usbi_cond_t *cond,
const usbi_condattr_t *attr) {
if(!cond) return ((errno=EINVAL));
list_init(&cond->waiters );
list_init(&cond->not_waiting);
return 0;
}
int usbi_cond_destroy(usbi_cond_t *cond) {
// This assumes no one is using this anymore. The check MAY NOT BE safe.
struct usbi_cond_perthread *pos, *prev_pos = NULL;
if(!cond) return ((errno=EINVAL));
if(!list_empty(&cond->waiters)) return ((errno=EBUSY )); // (!see above!)
list_for_each_entry(pos, &cond->not_waiting, list, struct usbi_cond_perthread) {
free(prev_pos);
list_del(&pos->list);
prev_pos = pos;
}
free(prev_pos);
prev_pos = pos = NULL;
return 0;
}
int usbi_cond_broadcast(usbi_cond_t *cond) {
// Assumes mutex is locked; this is not in keeping with POSIX spec, but
// libusb does this anyway, so we simplify by not adding more sync
// primitives to the CV definition!
int fail = 0;
struct usbi_cond_perthread *pos;
if(!cond) return ((errno=EINVAL));
list_for_each_entry(pos, &cond->waiters, list, struct usbi_cond_perthread) {
if(!SetEvent(pos->event))
fail = 1;
}
// The wait function will remove its respective item from the list.
return fail ? ((errno=EINVAL)) : 0;
}
int usbi_cond_signal(usbi_cond_t *cond) {
// Assumes mutex is locked; this is not in keeping with POSIX spec, but
// libusb does this anyway, so we simplify by not adding more sync
// primitives to the CV definition!
struct usbi_cond_perthread *pos;
if(!cond) return ((errno=EINVAL));
if(list_empty(&cond->waiters)) return 0; // no one to wakeup.
pos = list_entry(&cond->waiters.next, struct usbi_cond_perthread, list);
// The wait function will remove its respective item from the list.
return SetEvent(pos->event) ? 0 : ((errno=EINVAL));
}
static int __inline usbi_cond_intwait(usbi_cond_t *cond,
usbi_mutex_t *mutex,
DWORD timeout_ms) {
struct usbi_cond_perthread *pos;
int found = 0, r;
DWORD r2,tid = GetCurrentThreadId();
if(!cond || !mutex) return ((errno=EINVAL));
list_for_each_entry(pos, &cond->not_waiting, list, struct usbi_cond_perthread) {
if(tid == pos->tid) {
found = 1;
break;
}
}
if(!found) {
pos = malloc(sizeof(struct usbi_cond_perthread));
if(!pos) return ((errno=ENOMEM)); // This errno is not POSIX-allowed.
pos->tid = tid;
pos->event = CreateEvent(NULL, FALSE, FALSE, NULL); // auto-reset.
if(!pos->event) {
free(pos);
return ((errno=ENOMEM));
}
list_add(&pos->list, &cond->not_waiting);
}
list_del(&pos->list); // remove from not_waiting list.
list_add(&pos->list, &cond->waiters);
r = usbi_mutex_unlock(mutex);
if(r) return r;
r2 = WaitForSingleObject(pos->event, timeout_ms);
r = usbi_mutex_lock(mutex);
if(r) return r;
list_del(&pos->list);
list_add(&pos->list, &cond->not_waiting);
if(r2 == WAIT_TIMEOUT) return ((errno=ETIMEDOUT));
return 0;
}
// N.B.: usbi_cond_*wait() can also return ENOMEM, even though pthread_cond_*wait cannot!
int usbi_cond_wait(usbi_cond_t *cond, usbi_mutex_t *mutex) {
return usbi_cond_intwait(cond, mutex, INFINITE);
}
int usbi_cond_timedwait(usbi_cond_t *cond,
usbi_mutex_t *mutex,
const struct timespec *abstime) {
FILETIME ftime;
ULARGE_INTEGER rtime;
struct timeval targ_time, cur_time, delta_time;
struct timespec cur_time_ns;
DWORD millis;
extern const uint64_t epoch_time;
GetSystemTimeAsFileTime(&ftime);
rtime.LowPart = ftime.dwLowDateTime;
rtime.HighPart = ftime.dwHighDateTime;
rtime.QuadPart -= epoch_time;
cur_time_ns.tv_sec = (long)(rtime.QuadPart / 10000000);
cur_time_ns.tv_nsec = (long)((rtime.QuadPart % 10000000)*100);
TIMESPEC_TO_TIMEVAL(&cur_time, &cur_time_ns);
TIMESPEC_TO_TIMEVAL(&targ_time, abstime);
timersub(&targ_time, &cur_time, &delta_time);
if(delta_time.tv_sec <= 0) // abstime already passed?
millis = 0;
else {
millis = delta_time.tv_usec/1000;
millis += delta_time.tv_sec *1000;
}
return usbi_cond_intwait(cond, mutex, millis);
}
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