misc/events.c: Add a new way to send receive events. (ripped of from libvlc)....

misc/events.c: Add a new way to send receive events. (ripped of from libvlc). It will allow input_item to send events.

include/vlc_events.h

+/*****************************************************************************
+ * events.h: events definitions
+ * Interface used to send events.
+ *****************************************************************************
+ * Copyright (C) 2007 the VideoLAN team
+ * $Id$
+ *
+ * Authors: Pierre d'Herbemont
+ *
+ * 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 2 of the License, 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.
+ *****************************************************************************/
+
+#ifndef VLC_EVENTS_H
+# define VLC_EVENTS_H
+
+#include <vlc_arrays.h>
+
+/**
+ * \file
+ * This file is the interface definition for events
+ * (implementation in src/misc/events.c)
+ */
+
+/*****************************************************************************
+ * Documentation
+ *****************************************************************************/
+/*
+ **** Background
+ *
+ * This implements a way to send and receive event for an object (which can be
+ * a simple C struct or less).
+ * 
+ * This is in direct concurrency with the Variable based Callback
+ * (see src/misc/variables.c).
+ *
+ * It has the following advantages over Variable based Callback:
+ * - No need to implement the whole VLC_COMMON_MEMBERS in the object,
+ * thus it reduce it size. This is especially true for input_item_t which
+ * doesn't have VLC_COMMON_MEMBERS. This is the first reason of existence of
+ * this implementation.
+ * - Libvlc can easily be based upon that.
+ * - Existing event are clearly declared (in include/vlc_events.h)
+ *
+ *
+ **** Example usage
+ *
+ * (vlc_cool_object_t doesn't need to have the VLC_COMMON_MEMBERS.)
+ *
+ * struct vlc_cool_object_t 
+ * {
+ *        ...
+ *        vlc_event_manager_t p_event_manager;
+ *        ...
+ * }
+ *
+ * vlc_my_cool_object_new()
+ * {
+ *        ...
+ *        vlc_event_manager_Create( &p_self->p_event_manager, p_this );
+ *        vlc_event_manager_register_event_type(p_self->p_event_manager,
+ *                vlc_MyCoolObjectDidSomething, p_e)
+ *        ...
+ * }
+ *
+ * vlc_my_cool_object_release()
+ * {
+ *         ...
+ *         vlc_event_manager_release( p_self->p_event_manager );
+ *         ...
+ * }
+ *
+ * vlc_my_cool_object_do_something()
+ * {
+ *        ...
+ *        vlc_event_t event;
+ *        event.type = vlc_MyCoolObjectDidSomething;
+ *        event.u.my_cool_object_did_something.what_it_did = kSomething;
+ *        vlc_event_send( p_self->p_event_manager, &event );
+ * }
+ * */
+ 
+  /*****************************************************************************
+ * Event Type
+ *****************************************************************************/
+
+/* Private structure defined in misc/events.c */
+struct vlc_event_listeners_group_t;
+
+/* Event manager type */
+typedef struct vlc_event_manager_t
+{
+    void * p_obj;
+    DECL_ARRAY(struct vlc_event_listeners_group_t *) listeners_groups;
+} vlc_event_manager_t;
+
+/* List of event */
+typedef enum vlc_event_type_t {
+    vlc_InputItemMetaChanged
+} vlc_event_type_t;
+
+/* Event definition */
+typedef struct vlc_event_t
+{
+    vlc_event_type_t type;
+    void * p_obj; /* Sender object, automatically filled by event_Send() */
+    union event_type_specific
+    {
+        struct
+        {
+            int meta; /* One of the meta identified in include/vlc_meta.h */
+        } input_item_meta_changed;
+    } u;
+} vlc_event_t;
+
+/* Event callback type */
+typedef void ( *vlc_event_callback_t )( const vlc_event_t *, void * );
+
+ /*****************************************************************************
+ * Event manager
+ *****************************************************************************/
+
+/*
+ * p_obj points to the object that owns the event manager, and from
+ * which events are sent
+ */
+int event_manager_Create( vlc_event_manager_t * p_em, void * p_obj );
+
+/*
+ * Destroy
+ */
+void event_manager_Destroy( vlc_event_manager_t * p_em );
+
+/*
+ * Tells a specific event manager that it will handle event_type object
+ */
+int event_manager_RegisterEventType( vlc_event_manager_t * p_em,
+                                     vlc_event_type_t event_type );
+
+/*
+ * Send an event to the listener attached to this p_em.
+ */
+void event_Send( vlc_event_manager_t * p_em, vlc_event_t * p_event );
+
+/*
+ * Add a callback for an event.
+ */
+int event_Attach( vlc_event_manager_t * p_event_manager,
+                  vlc_event_type_t event_type,
+                  vlc_event_callback_t pf_callback,
+                  void *p_user_data );
+
+/*
+ * Remove a callback for an event.
+ */
+int event_Detach( vlc_event_manager_t *p_event_manager,
+                   vlc_event_type_t event_type,
+                   vlc_event_callback_t pf_callback,
+                   void *p_user_data );
+
+#endif /* VLC_EVENTS_H */

src/Makefile.am

@@ -265,6 +265,7 @@ SOURCES_libvlc_common = \
 	modules/configuration.h \
 	modules/configuration.c \
 	modules/configuration_chain.c \
+	misc/events.c \
 	misc/image.c \
 	misc/messages.c \
 	misc/objects.c \

src/misc/events.c

+/*****************************************************************************
+ * events.c: events interface
+ * This library provides an interface to the send and receive events.
+ * It is more lightweight than variable based callback.
+ * Methode
+ *****************************************************************************
+ * Copyright (C) 1998-2005 the VideoLAN team
+ * $Id$
+ *
+ * Authors: Pierre d'Herbemont <pdherbemont # videolan.org >
+ *
+ * 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 2 of the License, 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.
+ *****************************************************************************/
+
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+
+#include <vlc/vlc.h>
+
+#include <stdio.h>                                               /* required */
+#include <stdlib.h>                                              /* malloc() */
+
+#include <assert.h>
+
+#include <vlc_events.h>
+#include <vlc_arrays.h>
+
+/*****************************************************************************
+ * Documentation : Read vlc_events.h
+ *****************************************************************************/
+
+/*****************************************************************************
+ *  Private types.
+ *****************************************************************************/
+
+typedef struct vlc_event_listener_t
+{
+    void *               p_user_data;
+    vlc_event_callback_t pf_callback;
+} vlc_event_listener_t;
+
+typedef struct vlc_event_listeners_group_t
+{
+    vlc_event_type_t    event_type;
+    DECL_ARRAY(struct vlc_event_listener_t *) listeners;
+} vlc_event_listeners_group_t;
+
+/*****************************************************************************
+ * 
+ *****************************************************************************/
+
+/**
+ * Initialize event manager object
+ * p_this is the object that contains the event manager. But not
+ * necessarily a vlc_object_t (an input_item_t is not a vlc_object_t
+ * for instance).
+ */
+int event_manager_Create( vlc_event_manager_t * p_em, void * p_obj )
+{
+    p_em->p_obj = p_obj;
+    ARRAY_INIT( p_em->listeners_groups );
+    return VLC_SUCCESS;
+}
+
+/**
+ * Destroy the event manager
+ */
+void event_manager_Destroy( vlc_event_manager_t * p_em )
+{
+    struct vlc_event_listeners_group_t * listeners_group;
+    struct vlc_event_listener_t * listener;
+
+    FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
+        FOREACH_ARRAY( listener, listeners_group->listeners )
+            free( listener );
+        FOREACH_END()
+        free( listeners_group );
+    FOREACH_END()
+    free( p_em );
+}
+
+/**
+ * Destroy the event manager
+ */
+int event_manager_RegisterEventType(
+        vlc_event_manager_t * p_em,
+        vlc_event_type_t event_type )
+{
+    vlc_event_listeners_group_t * listeners_group;
+    listeners_group = malloc(sizeof(vlc_event_listeners_group_t));
+
+    if( !listeners_group )
+        return VLC_ENOMEM;
+
+    listeners_group->event_type = event_type;
+    ARRAY_INIT( listeners_group->listeners );
+
+    ARRAY_APPEND( p_em->listeners_groups, listeners_group );
+
+    return VLC_SUCCESS;
+}
+
+/**
+ * Send an event to the listener attached to this p_em.
+ */
+void event_Send( vlc_event_manager_t * p_em,
+                 vlc_event_t * p_event )
+{
+    vlc_event_listeners_group_t * listeners_group;
+    vlc_event_listener_t * listener;
+
+    /* Fill event with the sending object now */
+    p_event->p_obj = p_em->p_obj;
+
+    FOREACH_ARRAY( listeners_group, p_em->listeners_groups )
+        if( listeners_group->event_type == p_event->type )
+        {
+            /* We found the group, now send every one the event */
+            FOREACH_ARRAY( listener, listeners_group->listeners )
+                listener->pf_callback( p_event, listener->p_user_data );
+            FOREACH_END()
+            break;
+        }
+    FOREACH_END()
+}
+
+/**
+ * Add a callback for an event.
+ */
+int event_Attach( vlc_event_manager_t * p_event_manager,
+                  vlc_event_type_t event_type,
+                  vlc_event_callback_t pf_callback,
+                  void *p_user_data )
+{
+    vlc_event_listeners_group_t * listeners_group;
+    vlc_event_listener_t * listener;
+    listener = malloc(sizeof(vlc_event_listener_t));
+    if( !listener )
+        return VLC_ENOMEM;
+    
+    listener->p_user_data = p_user_data;
+    listener->pf_callback = pf_callback;
+    
+    FOREACH_ARRAY( listeners_group, p_event_manager->listeners_groups )
+        if( listeners_group->event_type == event_type )
+        {
+            ARRAY_APPEND( listeners_group->listeners, listener );
+            return VLC_SUCCESS;
+        }
+    FOREACH_END()
+    
+    free(listener);
+    return VLC_EGENERIC;
+}
+
+/**
+ * Remove a callback for an event.
+ */
+int event_Detach( vlc_event_manager_t *p_event_manager,
+                   vlc_event_type_t event_type,
+                   vlc_event_callback_t pf_callback,
+                   void *p_user_data )
+{
+    vlc_event_listeners_group_t * listeners_group;
+    struct vlc_event_listener_t * listener;
+    FOREACH_ARRAY( listeners_group, p_event_manager->listeners_groups )
+        if( listeners_group->event_type == event_type )
+        {
+            FOREACH_ARRAY( listener, listeners_group->listeners )
+                if( listener->pf_callback == pf_callback &&
+                    listener->p_user_data == p_user_data )
+                {
+                    /* that's our listener */
+                    free( listener );
+                    ARRAY_REMOVE( listeners_group->listeners,
+                        fe_idx /* This comes from the macro (and that's why
+                                  I hate macro) */ );
+                    return VLC_SUCCESS;
+                }
+            FOREACH_END()
+        }
+    FOREACH_END()
+
+    return VLC_EGENERIC;
+}
+
+