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-rw-r--r--lib/glthread/cond.c464
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diff --git a/lib/glthread/cond.c b/lib/glthread/cond.c
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index 909eb71..0000000
--- a/lib/glthread/cond.c
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@@ -1,464 +0,0 @@
-/* Condition variables for multithreading.
- Copyright (C) 2008 Free Software Foundation, Inc.
-
- This program is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published by
- the Free Software Foundation; either version 3, or (at your option)
- any later version.
-
- This program 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 General Public License for more details.
-
- You should have received a copy of the GNU General Public License
- along with this program; if not, write to the Free Software Foundation,
- Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
-
-/* Written by Yoann Vandoorselaere <yoann@prelude-ids.org>, 2008,
- and Bruno Haible <bruno@clisp.org>, 2008. */
-
-#include <config.h>
-
-#include "glthread/cond.h"
-
-/* ========================================================================= */
-
-#if USE_PTH_THREADS
-
-/* -------------------------- gl_cond_t datatype -------------------------- */
-
-int
-glthread_cond_timedwait_multithreaded (gl_cond_t *cond,
- gl_lock_t *lock,
- struct timespec *abstime)
-{
- int ret, status;
- pth_event_t ev;
-
- ev = pth_event (PTH_EVENT_TIME, pth_time (abstime->tv_sec, abstime->tv_nsec / 1000));
- ret = pth_cond_await (cond, lock, ev);
-
- status = pth_event_status (ev);
- pth_event_free (ev, PTH_FREE_THIS);
-
- if (status == PTH_STATUS_OCCURRED)
- return ETIMEDOUT;
-
- return ret;
-}
-
-#endif
-
-/* ========================================================================= */
-
-#if USE_SOLARIS_THREADS
-
-/* -------------------------- gl_cond_t datatype -------------------------- */
-
-int
-glthread_cond_timedwait_multithreaded (gl_cond_t *cond,
- gl_lock_t *lock,
- struct timespec *abstime)
-{
- int ret;
-
- ret = cond_timedwait (cond, lock, abstime);
- if (ret == ETIME)
- return ETIMEDOUT;
- return ret;
-}
-
-#endif
-
-/* ========================================================================= */
-
-#if USE_WIN32_THREADS
-
-#include <sys/time.h>
-
-/* -------------------------- gl_cond_t datatype -------------------------- */
-
-/* In this file, the waitqueues are implemented as linked lists. */
-#define gl_waitqueue_t gl_linked_waitqueue_t
-
-/* All links of a circular list, except the anchor, are of this type, carrying
- a payload. */
-struct gl_waitqueue_element
-{
- struct gl_waitqueue_link link; /* must be the first field! */
- HANDLE event; /* Waiting thread, represented by an event.
- This field is immutable once initialized. */
-};
-
-static inline void
-gl_waitqueue_init (gl_waitqueue_t *wq)
-{
- wq->wq_list.wql_next = &wq->wq_list;
- wq->wq_list.wql_prev = &wq->wq_list;
-}
-
-/* Enqueues the current thread, represented by an event, in a wait queue.
- Returns NULL if an allocation failure occurs. */
-static struct gl_waitqueue_element *
-gl_waitqueue_add (gl_waitqueue_t *wq)
-{
- struct gl_waitqueue_element *elt;
- HANDLE event;
-
- /* Allocate the memory for the waitqueue element on the heap, not on the
- thread's stack. If the thread exits unexpectedly, we prefer to leak
- some memory rather than to access unavailable memory and crash. */
- elt =
- (struct gl_waitqueue_element *)
- malloc (sizeof (struct gl_waitqueue_element));
- if (elt == NULL)
- /* No more memory. */
- return NULL;
-
- /* Whether the created event is a manual-reset one or an auto-reset one,
- does not matter, since we will wait on it only once. */
- event = CreateEvent (NULL, TRUE, FALSE, NULL);
- if (event == INVALID_HANDLE_VALUE)
- {
- /* No way to allocate an event. */
- free (elt);
- return NULL;
- }
- elt->event = event;
- /* Insert elt at the end of the circular list. */
- (elt->link.wql_prev = wq->wq_list.wql_prev)->wql_next = &elt->link;
- (elt->link.wql_next = &wq->wq_list)->wql_prev = &elt->link;
- return elt;
-}
-
-/* Removes the current thread, represented by a 'struct gl_waitqueue_element *',
- from a wait queue.
- Returns true if is was found and removed, false if it was not present. */
-static inline bool
-gl_waitqueue_remove (gl_waitqueue_t *wq, struct gl_waitqueue_element *elt)
-{
- if (elt->link.wql_next != NULL && elt->link.wql_prev != NULL)
- {
- /* Remove elt from the circular list. */
- struct gl_waitqueue_link *prev = elt->link.wql_prev;
- struct gl_waitqueue_link *next = elt->link.wql_next;
- prev->wql_next = next;
- next->wql_prev = prev;
- elt->link.wql_next = NULL;
- elt->link.wql_prev = NULL;
- return true;
- }
- else
- return false;
-}
-
-/* Notifies the first thread from a wait queue and dequeues it. */
-static inline void
-gl_waitqueue_notify_first (gl_waitqueue_t *wq)
-{
- if (wq->wq_list.wql_next != &wq->wq_list)
- {
- struct gl_waitqueue_element *elt =
- (struct gl_waitqueue_element *) wq->wq_list.wql_next;
- struct gl_waitqueue_link *prev;
- struct gl_waitqueue_link *next;
-
- /* Remove elt from the circular list. */
- prev = &wq->wq_list; /* = elt->link.wql_prev; */
- next = elt->link.wql_next;
- prev->wql_next = next;
- next->wql_prev = prev;
- elt->link.wql_next = NULL;
- elt->link.wql_prev = NULL;
-
- SetEvent (elt->event);
- /* After the SetEvent, this thread cannot access *elt any more, because
- the woken-up thread will quickly call free (elt). */
- }
-}
-
-/* Notifies all threads from a wait queue and dequeues them all. */
-static inline void
-gl_waitqueue_notify_all (gl_waitqueue_t *wq)
-{
- struct gl_waitqueue_link *l;
-
- for (l = wq->wq_list.wql_next; l != &wq->wq_list; )
- {
- struct gl_waitqueue_element *elt = (struct gl_waitqueue_element *) l;
- struct gl_waitqueue_link *prev;
- struct gl_waitqueue_link *next;
-
- /* Remove elt from the circular list. */
- prev = &wq->wq_list; /* = elt->link.wql_prev; */
- next = elt->link.wql_next;
- prev->wql_next = next;
- next->wql_prev = prev;
- elt->link.wql_next = NULL;
- elt->link.wql_prev = NULL;
-
- SetEvent (elt->event);
- /* After the SetEvent, this thread cannot access *elt any more, because
- the woken-up thread will quickly call free (elt). */
-
- l = next;
- }
- if (!(wq->wq_list.wql_next == &wq->wq_list
- && wq->wq_list.wql_prev == &wq->wq_list))
- abort ();
-}
-
-int
-glthread_cond_init_func (gl_cond_t *cond)
-{
- InitializeCriticalSection (&cond->lock);
- gl_waitqueue_init (&cond->waiters);
-
- cond->guard.done = 1;
- return 0;
-}
-
-int
-glthread_cond_wait_func (gl_cond_t *cond, gl_lock_t *lock)
-{
- if (!cond->guard.done)
- {
- if (InterlockedIncrement (&cond->guard.started) == 0)
- /* This thread is the first one to need this condition variable.
- Initialize it. */
- glthread_cond_init (cond);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this condition variable. */
- while (!cond->guard.done)
- Sleep (0);
- }
-
- EnterCriticalSection (&cond->lock);
- {
- struct gl_waitqueue_element *elt = gl_waitqueue_add (&cond->waiters);
- LeaveCriticalSection (&cond->lock);
- if (elt == NULL)
- {
- /* Allocation failure. Weird. */
- return EAGAIN;
- }
- else
- {
- HANDLE event = elt->event;
- int err;
- DWORD result;
-
- /* Now release the lock and let any other thread take it. */
- err = glthread_lock_unlock (lock);
- if (err != 0)
- {
- EnterCriticalSection (&cond->lock);
- gl_waitqueue_remove (&cond->waiters, elt);
- LeaveCriticalSection (&cond->lock);
- CloseHandle (event);
- free (elt);
- return err;
- }
- /* POSIX says:
- "If another thread is able to acquire the mutex after the
- about-to-block thread has released it, then a subsequent call to
- pthread_cond_broadcast() or pthread_cond_signal() in that thread
- shall behave as if it were issued after the about-to-block thread
- has blocked."
- This is fulfilled here, because the thread signalling is done
- through SetEvent, not PulseEvent. */
- /* Wait until another thread signals this event. */
- result = WaitForSingleObject (event, INFINITE);
- if (result == WAIT_FAILED || result == WAIT_TIMEOUT)
- abort ();
- CloseHandle (event);
- free (elt);
- /* The thread which signalled the event already did the bookkeeping:
- removed us from the waiters. */
- return glthread_lock_lock (lock);
- }
- }
-}
-
-int
-glthread_cond_timedwait_func (gl_cond_t *cond, gl_lock_t *lock, struct timespec *abstime)
-{
- struct timeval currtime;
-
- gettimeofday (&currtime, NULL);
- if (currtime.tv_sec > abstime->tv_sec
- || (currtime.tv_sec == abstime->tv_sec
- && currtime.tv_usec * 1000 >= abstime->tv_nsec))
- return ETIMEDOUT;
-
- if (!cond->guard.done)
- {
- if (InterlockedIncrement (&cond->guard.started) == 0)
- /* This thread is the first one to need this condition variable.
- Initialize it. */
- glthread_cond_init (cond);
- else
- /* Yield the CPU while waiting for another thread to finish
- initializing this condition variable. */
- while (!cond->guard.done)
- Sleep (0);
- }
-
- EnterCriticalSection (&cond->lock);
- {
- struct gl_waitqueue_element *elt = gl_waitqueue_add (&cond->waiters);
- LeaveCriticalSection (&cond->lock);
- if (elt == NULL)
- {
- /* Allocation failure. Weird. */
- return EAGAIN;
- }
- else
- {
- HANDLE event = elt->event;
- int err;
- DWORD timeout;
- DWORD result;
-
- /* Now release the lock and let any other thread take it. */
- err = glthread_lock_unlock (lock);
- if (err != 0)
- {
- EnterCriticalSection (&cond->lock);
- gl_waitqueue_remove (&cond->waiters, elt);
- LeaveCriticalSection (&cond->lock);
- CloseHandle (event);
- free (elt);
- return err;
- }
- /* POSIX says:
- "If another thread is able to acquire the mutex after the
- about-to-block thread has released it, then a subsequent call to
- pthread_cond_broadcast() or pthread_cond_signal() in that thread
- shall behave as if it were issued after the about-to-block thread
- has blocked."
- This is fulfilled here, because the thread signalling is done
- through SetEvent, not PulseEvent. */
- /* Wait until another thread signals this event or until the abstime
- passes. */
- gettimeofday (&currtime, NULL);
- if (currtime.tv_sec > abstime->tv_sec)
- timeout = 0;
- else
- {
- unsigned long seconds = abstime->tv_sec - currtime.tv_sec;
- timeout = seconds * 1000;
- if (timeout / 1000 != seconds) /* overflow? */
- timeout = INFINITE;
- else
- {
- long milliseconds =
- abstime->tv_nsec / 1000000 - currtime.tv_usec / 1000;
- if (milliseconds >= 0)
- {
- timeout += milliseconds;
- if (timeout < milliseconds) /* overflow? */
- timeout = INFINITE;
- }
- else
- {
- if (timeout >= - milliseconds)
- timeout -= (- milliseconds);
- else
- timeout = 0;
- }
- }
- }
- result = WaitForSingleObject (event, timeout);
- if (result == WAIT_FAILED)
- abort ();
- if (result == WAIT_TIMEOUT)
- {
- EnterCriticalSection (&cond->lock);
- if (gl_waitqueue_remove (&cond->waiters, elt))
- {
- /* The event was not signaled between the WaitForSingleObject
- call and the EnterCriticalSection call. */
- if (!(WaitForSingleObject (event, 0) == WAIT_TIMEOUT))
- abort ();
- }
- else
- {
- /* The event was signaled between the WaitForSingleObject
- call and the EnterCriticalSection call. */
- if (!(WaitForSingleObject (event, 0) == WAIT_OBJECT_0))
- abort ();
- /* Produce the right return value. */
- result = WAIT_OBJECT_0;
- }
- LeaveCriticalSection (&cond->lock);
- }
- else
- {
- /* The thread which signalled the event already did the
- bookkeeping: removed us from the waiters. */
- }
- CloseHandle (event);
- free (elt);
- /* Take the lock again. It does not matter whether this is done
- before or after the bookkeeping for WAIT_TIMEOUT. */
- err = glthread_lock_lock (lock);
- return (err ? err :
- result == WAIT_OBJECT_0 ? 0 :
- result == WAIT_TIMEOUT ? ETIMEDOUT :
- /* WAIT_FAILED shouldn't happen */ EAGAIN);
- }
- }
-}
-
-int
-glthread_cond_signal_func (gl_cond_t *cond)
-{
- if (!cond->guard.done)
- return EINVAL;
-
- EnterCriticalSection (&cond->lock);
- /* POSIX says:
- "The pthread_cond_broadcast() and pthread_cond_signal() functions shall
- have no effect if there are no threads currently blocked on cond." */
- if (cond->waiters.wq_list.wql_next != &cond->waiters.wq_list)
- gl_waitqueue_notify_first (&cond->waiters);
- LeaveCriticalSection (&cond->lock);
-
- return 0;
-}
-
-int
-glthread_cond_broadcast_func (gl_cond_t *cond)
-{
- if (!cond->guard.done)
- return EINVAL;
-
- EnterCriticalSection (&cond->lock);
- /* POSIX says:
- "The pthread_cond_broadcast() and pthread_cond_signal() functions shall
- have no effect if there are no threads currently blocked on cond."
- gl_waitqueue_notify_all is a nop in this case. */
- gl_waitqueue_notify_all (&cond->waiters);
- LeaveCriticalSection (&cond->lock);
-
- return 0;
-}
-
-int
-glthread_cond_destroy_func (gl_cond_t *cond)
-{
- if (!cond->guard.done)
- return EINVAL;
- if (cond->waiters.wq_list.wql_next != &cond->waiters.wq_list)
- return EBUSY;
- DeleteCriticalSection (&cond->lock);
- cond->guard.done = 0;
- return 0;
-}
-
-#endif
-
-/* ========================================================================= */
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