mirror of
https://code.videolan.org/videolan/vlc
synced 2024-10-11 06:21:30 +02:00
9abcaacf83
Signed-off-by: Rémi Denis-Courmont <remi@remlab.net>
288 lines
8.5 KiB
C
288 lines
8.5 KiB
C
/*****************************************************************************
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* event_async.c: New libvlc event control API
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*****************************************************************************
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* Copyright (C) 2007 VLC authors and VideoLAN
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* $Id $
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*
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* Authors: Filippo Carone <filippo@carone.org>
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* Pierre d'Herbemont <pdherbemont # videolan.org>
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU Lesser General Public License as published by
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* the Free Software Foundation; either version 2.1 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public License
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* along with this program; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
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*****************************************************************************/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <assert.h>
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#include <vlc/libvlc.h>
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#include "libvlc_internal.h"
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#include "event_internal.h"
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struct queue_elmt {
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libvlc_event_listener_t listener;
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libvlc_event_t event;
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struct queue_elmt * next;
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};
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struct libvlc_event_async_queue {
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struct queue_elmt *first_elmt, *last_elmt;
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vlc_mutex_t lock;
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vlc_cond_t signal;
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vlc_thread_t thread;
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bool is_idle;
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vlc_cond_t signal_idle;
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vlc_threadvar_t is_asynch_dispatch_thread_var;
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};
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/*
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* Utilities
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*/
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static void* event_async_loop(void * arg);
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static inline struct libvlc_event_async_queue * queue(libvlc_event_manager_t * p_em)
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{
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return p_em->async_event_queue;
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}
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static inline bool is_queue_initialized(libvlc_event_manager_t * p_em)
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{
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return queue(p_em) != NULL;
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}
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static inline bool current_thread_is_asynch_thread(libvlc_event_manager_t * p_em)
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{
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return vlc_threadvar_get(queue(p_em)->is_asynch_dispatch_thread_var)
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!= NULL;
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}
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/* Lock must be held */
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static void push(libvlc_event_manager_t * p_em,
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libvlc_event_listener_t * listener, libvlc_event_t * event)
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{
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struct queue_elmt * elmt = malloc(sizeof(struct queue_elmt));
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elmt->listener = *listener;
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elmt->event = *event;
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elmt->next = NULL;
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/* Append to the end of the queue */
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if(!queue(p_em)->first_elmt)
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queue(p_em)->first_elmt = elmt;
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else
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queue(p_em)->last_elmt->next = elmt;
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queue(p_em)->last_elmt = elmt;
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}
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static inline void queue_lock(libvlc_event_manager_t * p_em)
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{
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vlc_mutex_lock(&queue(p_em)->lock);
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}
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static inline void queue_unlock(libvlc_event_manager_t * p_em)
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{
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vlc_mutex_unlock(&queue(p_em)->lock);
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}
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/* Lock must be held */
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static bool pop(libvlc_event_manager_t * p_em,
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libvlc_event_listener_t * listener, libvlc_event_t * event)
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{
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if(!queue(p_em)->first_elmt)
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return false; /* No first_elmt */
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struct queue_elmt * elmt = queue(p_em)->first_elmt;
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*listener = elmt->listener;
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*event = elmt->event;
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queue(p_em)->first_elmt = elmt->next;
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if( !elmt->next ) queue(p_em)->last_elmt=NULL;
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free(elmt);
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return true;
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}
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/* Lock must be held */
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static void pop_listener(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener)
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{
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struct queue_elmt * iter = queue(p_em)->first_elmt;
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struct queue_elmt * prev = NULL;
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while (iter) {
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if(listeners_are_equal(&iter->listener, listener))
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{
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struct queue_elmt * to_delete = iter;
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if(!prev)
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queue(p_em)->first_elmt = to_delete->next;
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else
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prev->next = to_delete->next;
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iter = to_delete->next;
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free(to_delete);
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}
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else {
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prev = iter;
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iter = iter->next;
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}
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}
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queue(p_em)->last_elmt=prev;
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}
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/**************************************************************************
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* libvlc_event_async_fini (internal) :
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*
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* Destroy what might have been created by.
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**************************************************************************/
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void
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libvlc_event_async_fini(libvlc_event_manager_t * p_em)
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{
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if(!is_queue_initialized(p_em)) return;
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if(current_thread_is_asynch_thread(p_em))
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{
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fprintf(stderr, "*** Error: releasing the last reference of the observed object from its callback thread is not (yet!) supported\n");
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abort();
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}
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vlc_thread_t thread = queue(p_em)->thread;
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if(thread)
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{
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vlc_cancel(thread);
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vlc_join(thread, NULL);
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}
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vlc_mutex_destroy(&queue(p_em)->lock);
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vlc_cond_destroy(&queue(p_em)->signal);
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vlc_cond_destroy(&queue(p_em)->signal_idle);
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vlc_threadvar_delete(&queue(p_em)->is_asynch_dispatch_thread_var);
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struct queue_elmt * iter = queue(p_em)->first_elmt;
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while (iter) {
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struct queue_elmt * elemt_to_delete = iter;
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iter = iter->next;
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free(elemt_to_delete);
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}
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free(queue(p_em));
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}
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/**************************************************************************
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* libvlc_event_async_init (private) :
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*
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* Destroy what might have been created by.
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**************************************************************************/
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static void
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libvlc_event_async_init(libvlc_event_manager_t * p_em)
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{
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p_em->async_event_queue = calloc(1, sizeof(struct libvlc_event_async_queue));
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int error = vlc_threadvar_create(&queue(p_em)->is_asynch_dispatch_thread_var, NULL);
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assert(!error);
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vlc_mutex_init(&queue(p_em)->lock);
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vlc_cond_init(&queue(p_em)->signal);
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vlc_cond_init(&queue(p_em)->signal_idle);
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error = vlc_clone (&queue(p_em)->thread, event_async_loop, p_em, VLC_THREAD_PRIORITY_LOW);
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if(error)
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{
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free(p_em->async_event_queue);
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p_em->async_event_queue = NULL;
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return;
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}
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}
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/**************************************************************************
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* libvlc_event_async_ensure_listener_removal (internal) :
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*
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* Make sure no more message will be issued to the listener.
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**************************************************************************/
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void
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libvlc_event_async_ensure_listener_removal(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener)
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{
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if(!is_queue_initialized(p_em)) return;
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queue_lock(p_em);
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pop_listener(p_em, listener);
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// Wait for the asynch_loop to have processed all events.
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if(!current_thread_is_asynch_thread(p_em))
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{
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while(!queue(p_em)->is_idle)
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vlc_cond_wait(&queue(p_em)->signal_idle, &queue(p_em)->lock);
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}
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queue_unlock(p_em);
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}
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/**************************************************************************
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* libvlc_event_async_dispatch (internal) :
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*
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* Send an event in an asynchronous way.
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**************************************************************************/
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void
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libvlc_event_async_dispatch(libvlc_event_manager_t * p_em, libvlc_event_listener_t * listener, libvlc_event_t * event)
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{
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// We do a lazy init here, to prevent constructing the thread when not needed.
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vlc_mutex_lock(&p_em->object_lock);
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if(!queue(p_em))
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libvlc_event_async_init(p_em);
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vlc_mutex_unlock(&p_em->object_lock);
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queue_lock(p_em);
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push(p_em, listener, event);
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vlc_cond_signal(&queue(p_em)->signal);
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queue_unlock(p_em);
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}
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/**************************************************************************
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* event_async_loop (private) :
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*
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* Send queued events.
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**************************************************************************/
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static void * event_async_loop(void * arg)
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{
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libvlc_event_manager_t * p_em = arg;
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libvlc_event_listener_t listener;
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libvlc_event_t event;
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vlc_threadvar_set(queue(p_em)->is_asynch_dispatch_thread_var, p_em);
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queue_lock(p_em);
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while (true) {
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int has_listener = pop(p_em, &listener, &event);
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if (has_listener)
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{
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queue_unlock(p_em);
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listener.pf_callback(&event, listener.p_user_data); // This might edit the queue
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queue_lock(p_em);
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}
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else
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{
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queue(p_em)->is_idle = true;
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mutex_cleanup_push(&queue(p_em)->lock);
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vlc_cond_broadcast(&queue(p_em)->signal_idle); // We'll be idle
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vlc_cond_wait(&queue(p_em)->signal, &queue(p_em)->lock);
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vlc_cleanup_pop();
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queue(p_em)->is_idle = false;
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}
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}
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queue_unlock(p_em);
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return NULL;
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}
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