gstreamer/gst/gstmessage.c
Stefan Kost c73b03243a docs/design/part-messages.txt: update info
Original commit message from CVS:
* docs/design/part-messages.txt:
update info
* docs/gst/tmpl/.cvsignore:
* docs/gst/tmpl/gstcaps.sgml:
* docs/gst/tmpl/gstclock.sgml:
* gst/gstbus.c:
* gst/gstcaps.c:
* gst/gstcaps.h:
* gst/gstclock.c:
* gst/gstclock.h:
* gst/gstmessage.c:
added descriptions for bus and message
inline caps and clock docs
2005-08-27 10:57:00 +00:00

583 lines
16 KiB
C

/* GStreamer
* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
*
* gstmessage.c: GstMessage subsystem
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 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
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
/**
* SECTION:gstmessage
* @short_description: Lightweight objects to signal the application of pipeline events
* @see_also: #GstBus,#GstMiniObject
*
* Messages are implemented as a subclass of #GstMiniObject with a generic
* #GstStructure as the content. This allows for writing custom messages without
* requiring an API change while allowing a wide range of different types
* of messages.
*
* Messages are posted by objects in the pipeline and are passed to the
* application using the #GstBus.
*/
#include <string.h> /* memcpy */
#include "gst_private.h"
#include "gsterror.h"
#include "gstinfo.h"
#include "gstmemchunk.h"
#include "gstmessage.h"
#include "gsttag.h"
#include "gstutils.h"
static void gst_message_init (GTypeInstance * instance, gpointer g_class);
static void gst_message_class_init (gpointer g_class, gpointer class_data);
static void gst_message_finalize (GstMessage * message);
static GstMessage *_gst_message_copy (GstMessage * message);
void
_gst_message_initialize (void)
{
gpointer ptr;
GST_CAT_INFO (GST_CAT_GST_INIT, "init messages");
gst_message_get_type ();
/* the GstMiniObject types need to be class_ref'd once before it can be
* done from multiple threads;
* see http://bugzilla.gnome.org/show_bug.cgi?id=304551 */
ptr = g_type_class_ref (GST_TYPE_MESSAGE);
g_type_class_unref (ptr);
}
GType
gst_message_get_type (void)
{
static GType _gst_message_type;
if (G_UNLIKELY (_gst_message_type == 0)) {
static const GTypeInfo message_info = {
sizeof (GstMessageClass),
NULL,
NULL,
gst_message_class_init,
NULL,
NULL,
sizeof (GstMessage),
0,
gst_message_init,
NULL
};
_gst_message_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
"GstMessage", &message_info, 0);
}
return _gst_message_type;
}
static void
gst_message_class_init (gpointer g_class, gpointer class_data)
{
GstMessageClass *message_class = GST_MESSAGE_CLASS (g_class);
message_class->mini_object_class.copy =
(GstMiniObjectCopyFunction) _gst_message_copy;
message_class->mini_object_class.finalize =
(GstMiniObjectFinalizeFunction) gst_message_finalize;
}
static void
gst_message_init (GTypeInstance * instance, gpointer g_class)
{
GstMessage *message = GST_MESSAGE (instance);
GST_CAT_INFO (GST_CAT_MESSAGE, "new message %p", message);
GST_MESSAGE_TIMESTAMP (message) = GST_CLOCK_TIME_NONE;
}
static void
gst_message_finalize (GstMessage * message)
{
g_return_if_fail (message != NULL);
GST_CAT_INFO (GST_CAT_MESSAGE, "finalize message %p", message);
if (GST_MESSAGE_SRC (message)) {
gst_object_unref (GST_MESSAGE_SRC (message));
GST_MESSAGE_SRC (message) = NULL;
}
if (message->lock) {
GST_MESSAGE_LOCK (message);
GST_MESSAGE_SIGNAL (message);
GST_MESSAGE_UNLOCK (message);
}
if (message->structure) {
gst_structure_set_parent_refcount (message->structure, NULL);
gst_structure_free (message->structure);
}
}
static GstMessage *
_gst_message_copy (GstMessage * message)
{
GstMessage *copy;
GST_CAT_INFO (GST_CAT_MESSAGE, "copy message %p", message);
copy = (GstMessage *) gst_mini_object_new (GST_TYPE_MESSAGE);
/* FIXME, need to copy relevant data from the miniobject. */
//memcpy (copy, message, sizeof (GstMessage));
GST_MESSAGE_GET_LOCK (copy) = GST_MESSAGE_GET_LOCK (message);
GST_MESSAGE_COND (copy) = GST_MESSAGE_COND (message);
GST_MESSAGE_TYPE (copy) = GST_MESSAGE_TYPE (message);
GST_MESSAGE_TIMESTAMP (copy) = GST_MESSAGE_TIMESTAMP (message);
if (GST_MESSAGE_SRC (message)) {
GST_MESSAGE_SRC (copy) = gst_object_ref (GST_MESSAGE_SRC (message));
}
if (message->structure) {
copy->structure = gst_structure_copy (message->structure);
gst_structure_set_parent_refcount (copy->structure,
&message->mini_object.refcount);
}
return copy;
}
static GstMessage *
gst_message_new (GstMessageType type, GstObject * src)
{
GstMessage *message;
message = (GstMessage *) gst_mini_object_new (GST_TYPE_MESSAGE);
GST_CAT_INFO (GST_CAT_MESSAGE, "creating new message %p %d", message, type);
message->type = type;
if (src) {
message->src = gst_object_ref (src);
GST_CAT_DEBUG_OBJECT (GST_CAT_MESSAGE, src, "message source");
} else {
message->src = NULL;
GST_CAT_DEBUG (GST_CAT_MESSAGE, "NULL message source");
}
message->structure = NULL;
return message;
}
/**
* gst_message_new_eos:
* @src: The object originating the message.
*
* Create a new eos message. This message is generated and posted in
* the sink elements of a GstBin. The bin will only forward the EOS
* message to the application if all sinks have posted an EOS message.
*
* Returns: The new eos message.
*
* MT safe.
*/
GstMessage *
gst_message_new_eos (GstObject * src)
{
GstMessage *message;
message = gst_message_new (GST_MESSAGE_EOS, src);
return message;
}
/**
* gst_message_new_error:
* @src: The object originating the message.
* @error: The GError for this message.
* @debug: A debugging string for something or other.
*
* Create a new error message. The message will copy @error and
* @debug. This message is posted by element when a fatal event
* occured. The pipeline will probably (partially) stop.
*
* Returns: The new error message.
*
* MT safe.
*/
GstMessage *
gst_message_new_error (GstObject * src, GError * error, gchar * debug)
{
GstMessage *message;
GstStructure *s;
message = gst_message_new (GST_MESSAGE_ERROR, src);
/* gst_structure_new takes copies of the types passed in */
s = gst_structure_new ("GstMessageError", "gerror", GST_TYPE_G_ERROR, error,
"debug", G_TYPE_STRING, debug, NULL);
gst_structure_set_parent_refcount (s, &message->mini_object.refcount);
message->structure = s;
return message;
}
/**
* gst_message_new_warning:
* @src: The object originating the message.
* @error: The GError for this message.
* @debug: A debugging string for something or other.
*
* Create a new warning message. The message will make copies of @error and
* @debug.
*
* Returns: The new warning message.
*
* MT safe.
*/
GstMessage *
gst_message_new_warning (GstObject * src, GError * error, gchar * debug)
{
GstMessage *message;
GstStructure *s;
message = gst_message_new (GST_MESSAGE_WARNING, src);
/* gst_structure_new takes copies of the types passed in */
s = gst_structure_new ("GstMessageWarning", "gerror", GST_TYPE_G_ERROR, error,
"debug", G_TYPE_STRING, debug, NULL);
gst_structure_set_parent_refcount (s, &message->mini_object.refcount);
message->structure = s;
return message;
}
/**
* gst_message_new_tag:
* @src: The object originating the message.
* @tag_list: The tag list for the message.
*
* Create a new tag message. The message will take ownership of the tag list.
* The message is posted by elements that discovered a new taglist.
*
* Returns: The new tag message.
*
* MT safe.
*/
GstMessage *
gst_message_new_tag (GstObject * src, GstTagList * tag_list)
{
GstMessage *message;
g_return_val_if_fail (GST_IS_STRUCTURE (tag_list), NULL);
message = gst_message_new (GST_MESSAGE_TAG, src);
gst_structure_set_parent_refcount (tag_list, &message->mini_object.refcount);
message->structure = tag_list;
return message;
}
/**
* gst_message_new_state_change:
* @src: The object originating the message.
* @old: The previous state.
* @new: The new (current) state.
*
* Create a state change message. This message is posted whenever an element changed
* its state.
*
* Returns: The new state change message.
*
* MT safe.
*/
GstMessage *
gst_message_new_state_changed (GstObject * src, GstElementState old,
GstElementState new)
{
GstMessage *message;
GstStructure *s;
message = gst_message_new (GST_MESSAGE_STATE_CHANGED, src);
s = gst_structure_new ("GstMessageState", "old-state", G_TYPE_INT, (gint) old,
"new-state", G_TYPE_INT, (gint) new, NULL);
gst_structure_set_parent_refcount (s, &message->mini_object.refcount);
message->structure = s;
return message;
}
/**
* gst_message_new_segment_start:
* @src: The object originating the message.
* @timestamp: The timestamp of the segment being played
*
* Create a new segment message. This message is posted by elements that
* start playback of a segment as a result of a segment seek. This message
* is not received by the application but is used for maintenance reasons in
* container elements.
*
* Returns: The new segment start message.
*
* MT safe.
*/
GstMessage *
gst_message_new_segment_start (GstObject * src, GstClockTime timestamp)
{
GstMessage *message;
GstStructure *s;
message = gst_message_new (GST_MESSAGE_SEGMENT_START, src);
s = gst_structure_new ("GstMessageSegmentStart", "timestamp", G_TYPE_INT64,
(gint64) timestamp, NULL);
gst_structure_set_parent_refcount (s, &message->mini_object.refcount);
message->structure = s;
return message;
}
/**
* gst_message_new_segment_done:
* @src: The object originating the message.
* @timestamp: The timestamp of the segment being played
*
* Create a new segment done message. This message is posted by elements that
* finish playback of a segment as a result of a segment seek. This message
* is received by the application after all elements that posted a segment_start
* have posted the segment_done.
*
* Returns: The new segment done message.
*
* MT safe.
*/
GstMessage *
gst_message_new_segment_done (GstObject * src, GstClockTime timestamp)
{
GstMessage *message;
GstStructure *s;
message = gst_message_new (GST_MESSAGE_SEGMENT_DONE, src);
s = gst_structure_new ("GstMessageSegmentDone", "timestamp", G_TYPE_INT64,
(gint64) timestamp, NULL);
gst_structure_set_parent_refcount (s, &message->mini_object.refcount);
message->structure = s;
return message;
}
/**
* gst_message_new_custom:
* @type: The #GstMessageType to distinguish messages
* @src: The object originating the message.
* @structure: The structure for the message. The message will take ownership of
* the structure.
*
* Create a new custom-typed message. This can be used for anything not
* handled by other message-specific functions to pass a message to the
* app. The structure field can be NULL.
*
* Returns: The new message.
*
* MT safe.
*/
GstMessage *
gst_message_new_custom (GstMessageType type, GstObject * src,
GstStructure * structure)
{
GstMessage *message;
message = gst_message_new (type, src);
if (structure) {
gst_structure_set_parent_refcount (structure,
&message->mini_object.refcount);
message->structure = structure;
}
return message;
}
/**
* gst_message_get_structure:
* @message: The #GstMessage.
*
* Access the structure of the message.
*
* Returns: The structure of the message. The structure is still
* owned by the message, which means that you should not free it and
* that the pointer becomes invalid when you free the message.
*
* MT safe.
*/
const GstStructure *
gst_message_get_structure (GstMessage * message)
{
g_return_val_if_fail (GST_IS_MESSAGE (message), NULL);
return message->structure;
}
/**
* gst_message_parse_tag:
* @message: A valid #GstMessage of type GST_MESSAGE_TAG.
*
* Extracts the tag list from the GstMessage. The tag list returned in the
* output argument is a copy; the caller must free it when done.
*
* MT safe.
*/
void
gst_message_parse_tag (GstMessage * message, GstTagList ** tag_list)
{
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_TAG);
*tag_list = (GstTagList *) gst_structure_copy (message->structure);
}
/**
* gst_message_parse_state_changed:
* @message: A valid #GstMessage of type GST_MESSAGE_STATE_CHANGED.
*
* Extracts the old and new states from the GstMessage.
*
* MT safe.
*/
void
gst_message_parse_state_changed (GstMessage * message, GstElementState * old,
GstElementState * new)
{
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_STATE_CHANGED);
if (!gst_structure_get_int (message->structure, "old-state", (gint *) old))
g_assert_not_reached ();
if (!gst_structure_get_int (message->structure, "new-state", (gint *) new))
g_assert_not_reached ();
}
/**
* gst_message_parse_error:
* @message: A valid #GstMessage of type GST_MESSAGE_ERROR.
*
* Extracts the GError and debug string from the GstMessage. The values returned
* in the output arguments are copies; the caller must free them when done.
*
* MT safe.
*/
void
gst_message_parse_error (GstMessage * message, GError ** gerror, gchar ** debug)
{
const GValue *error_gvalue;
GError *error_val;
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_ERROR);
error_gvalue = gst_structure_get_value (message->structure, "gerror");
g_return_if_fail (error_gvalue != NULL);
g_return_if_fail (G_VALUE_TYPE (error_gvalue) == GST_TYPE_G_ERROR);
error_val = (GError *) g_value_get_boxed (error_gvalue);
if (error_val)
*gerror = g_error_copy (error_val);
else
*gerror = NULL;
*debug = g_strdup (gst_structure_get_string (message->structure, "debug"));
}
/**
* gst_message_parse_warning:
* @message: A valid #GstMessage of type GST_MESSAGE_WARNING.
*
* Extracts the GError and debug string from the GstMessage. The values returned
* in the output arguments are copies; the caller must free them when done.
*
* MT safe.
*/
void
gst_message_parse_warning (GstMessage * message, GError ** gerror,
gchar ** debug)
{
const GValue *error_gvalue;
GError *error_val;
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_WARNING);
error_gvalue = gst_structure_get_value (message->structure, "gerror");
g_return_if_fail (error_gvalue != NULL);
g_return_if_fail (G_VALUE_TYPE (error_gvalue) == GST_TYPE_G_ERROR);
error_val = (GError *) g_value_get_boxed (error_gvalue);
if (error_val)
*gerror = g_error_copy (error_val);
else
*gerror = NULL;
*debug = g_strdup (gst_structure_get_string (message->structure, "debug"));
}
/**
* gst_message_parse_segment_start:
* @message: A valid #GstMessage of type GST_MESSAGE_SEGMENT_START.
*
* Extracts the timestamp from the segment start message.
*
* MT safe.
*/
void
gst_message_parse_segment_start (GstMessage * message, GstClockTime * timestamp)
{
const GValue *time_gvalue;
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_SEGMENT_START);
time_gvalue = gst_structure_get_value (message->structure, "timstamp");
g_return_if_fail (time_gvalue != NULL);
g_return_if_fail (G_VALUE_TYPE (time_gvalue) == G_TYPE_INT64);
if (timestamp)
*timestamp = (GstClockTime) g_value_get_int64 (time_gvalue);
}
/**
* gst_message_parse_segment_done:
* @message: A valid #GstMessage of type GST_MESSAGE_SEGMENT_DONE.
*
* Extracts the timestamp from the segment done message.
*
* MT safe.
*/
void
gst_message_parse_segment_done (GstMessage * message, GstClockTime * timestamp)
{
const GValue *time_gvalue;
g_return_if_fail (GST_IS_MESSAGE (message));
g_return_if_fail (GST_MESSAGE_TYPE (message) == GST_MESSAGE_SEGMENT_DONE);
time_gvalue = gst_structure_get_value (message->structure, "timstamp");
g_return_if_fail (time_gvalue != NULL);
g_return_if_fail (G_VALUE_TYPE (time_gvalue) == G_TYPE_INT64);
if (timestamp)
*timestamp = (GstClockTime) g_value_get_int64 (time_gvalue);
}