gstreamer/gst/gstquery.c
Wim Taymans 1901cd0471 gst/gstquery.*: More documentation.
Original commit message from CVS:
* gst/gstquery.c: (gst_query_new_segment), (gst_query_set_segment),
(gst_query_parse_segment):
* gst/gstquery.h:
More documentation.
Add segment query for future use.
2005-09-22 17:40:42 +00:00

601 lines
16 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wim.taymans@chello.be>
* 2005 Wim Taymans <wim@fluendo.com>
*
* gstquery.c: GstQueryType registration
*
* 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:gstquery
* @short_description: Dynamically register new query types and parse results
* @see_also: #GstPad, #GstElement
*
* GstQuery functions are used to register a new query types to the gstreamer core.
* Query types can be used to perform queries on pads and elements.
*
* Query answer can be parsed using gst_query_parse_xxx() helpers.
*/
#include <string.h>
#include "gst_private.h"
#include "gstquery.h"
#include "gstenumtypes.h"
GST_DEBUG_CATEGORY_STATIC (gst_query_debug);
#define GST_CAT_DEFAULT gst_query_debug
static void gst_query_init (GTypeInstance * instance, gpointer g_class);
static void gst_query_class_init (gpointer g_class, gpointer class_data);
static void gst_query_finalize (GstQuery * query);
static GstQuery *_gst_query_copy (GstQuery * query);
static GStaticMutex mutex = G_STATIC_MUTEX_INIT;
static GList *_gst_queries = NULL;
static GHashTable *_nick_to_query = NULL;
static GHashTable *_query_type_to_nick = NULL;
static guint32 _n_values = 1; /* we start from 1 because 0 reserved for NONE */
static GstQueryTypeDefinition standard_definitions[] = {
{GST_QUERY_POSITION, "position", "Current position and total duration"},
{GST_QUERY_LATENCY, "latency", "Latency"},
{GST_QUERY_JITTER, "jitter", "Jitter"},
{GST_QUERY_RATE, "rate", "Configured rate 1000000 = 1"},
{GST_QUERY_SEEKING, "seeking", "Seeking capabilities and parameters"},
{GST_QUERY_SEGMENT, "segment", "currently configured segment"},
{GST_QUERY_CONVERT, "convert", "Converting between formats"},
{GST_QUERY_FORMATS, "formats", "Supported formats for conversion"},
{0, NULL, NULL}
};
void
_gst_query_initialize (void)
{
GstQueryTypeDefinition *standards = standard_definitions;
GST_CAT_INFO (GST_CAT_GST_INIT, "init queries");
GST_DEBUG_CATEGORY_INIT (gst_query_debug, "query", 0, "query system");
g_static_mutex_lock (&mutex);
if (_nick_to_query == NULL) {
_nick_to_query = g_hash_table_new (g_str_hash, g_str_equal);
_query_type_to_nick = g_hash_table_new (NULL, NULL);
}
while (standards->nick) {
g_hash_table_insert (_nick_to_query, standards->nick, standards);
g_hash_table_insert (_query_type_to_nick,
GINT_TO_POINTER (standards->value), standards);
_gst_queries = g_list_append (_gst_queries, standards);
standards++;
_n_values++;
}
g_static_mutex_unlock (&mutex);
gst_query_get_type ();
}
GType
gst_query_get_type (void)
{
static GType _gst_query_type;
if (G_UNLIKELY (_gst_query_type == 0)) {
static const GTypeInfo query_info = {
sizeof (GstQueryClass),
NULL,
NULL,
gst_query_class_init,
NULL,
NULL,
sizeof (GstQuery),
0,
gst_query_init,
NULL
};
_gst_query_type = g_type_register_static (GST_TYPE_MINI_OBJECT,
"GstQuery", &query_info, 0);
}
return _gst_query_type;
}
static void
gst_query_class_init (gpointer g_class, gpointer class_data)
{
GstQueryClass *query_class = GST_QUERY_CLASS (g_class);
query_class->mini_object_class.copy =
(GstMiniObjectCopyFunction) _gst_query_copy;
query_class->mini_object_class.finalize =
(GstMiniObjectFinalizeFunction) gst_query_finalize;
}
static void
gst_query_finalize (GstQuery * query)
{
g_return_if_fail (query != NULL);
if (query->structure) {
gst_structure_set_parent_refcount (query->structure, NULL);
gst_structure_free (query->structure);
}
}
static void
gst_query_init (GTypeInstance * instance, gpointer g_class)
{
}
static GstQuery *
_gst_query_copy (GstQuery * query)
{
GstQuery *copy;
copy = (GstQuery *) gst_mini_object_new (GST_TYPE_QUERY);
copy->type = query->type;
if (query->structure) {
copy->structure = gst_structure_copy (query->structure);
gst_structure_set_parent_refcount (copy->structure,
&query->mini_object.refcount);
}
return copy;
}
/**
* gst_query_type_register:
* @nick: The nick of the new query
* @description: The description of the new query
*
* Create a new GstQueryType based on the nick or return an
* allrady registered query with that nick
*
* Returns: A new GstQueryType or an already registered query
* with the same nick.
*/
GstQueryType
gst_query_type_register (const gchar * nick, const gchar * description)
{
GstQueryTypeDefinition *query;
GstQueryType lookup;
g_return_val_if_fail (nick != NULL, 0);
g_return_val_if_fail (description != NULL, 0);
lookup = gst_query_type_get_by_nick (nick);
if (lookup != GST_QUERY_NONE)
return lookup;
query = g_new0 (GstQueryTypeDefinition, 1);
query->value = _n_values;
query->nick = g_strdup (nick);
query->description = g_strdup (description);
g_static_mutex_lock (&mutex);
g_hash_table_insert (_nick_to_query, query->nick, query);
g_hash_table_insert (_query_type_to_nick, GINT_TO_POINTER (query->value),
query);
_gst_queries = g_list_append (_gst_queries, query);
_n_values++;
g_static_mutex_unlock (&mutex);
return query->value;
}
/**
* gst_query_type_get_by_nick:
* @nick: The nick of the query
*
* Return the query registered with the given nick.
*
* Returns: The query with @nick or GST_QUERY_NONE
* if the query was not registered.
*/
GstQueryType
gst_query_type_get_by_nick (const gchar * nick)
{
GstQueryTypeDefinition *query;
g_return_val_if_fail (nick != NULL, 0);
g_static_mutex_lock (&mutex);
query = g_hash_table_lookup (_nick_to_query, nick);
g_static_mutex_unlock (&mutex);
if (query != NULL)
return query->value;
else
return GST_QUERY_NONE;
}
/**
* gst_query_types_contains:
* @types: The query array to search
* @type: the querytype to find
*
* See if the given query is inside the query array.
*
* Returns: TRUE if the query is found inside the array
*/
gboolean
gst_query_types_contains (const GstQueryType * types, GstQueryType type)
{
if (!types)
return FALSE;
while (*types) {
if (*types == type)
return TRUE;
types++;
}
return FALSE;
}
/**
* gst_query_type_get_details:
* @type: The query to get details of
*
* Get details about the given query.
*
* Returns: The #GstQueryTypeDefinition for @query or NULL on failure.
*/
const GstQueryTypeDefinition *
gst_query_type_get_details (GstQueryType type)
{
const GstQueryTypeDefinition *result;
g_static_mutex_lock (&mutex);
result = g_hash_table_lookup (_query_type_to_nick, GINT_TO_POINTER (type));
g_static_mutex_unlock (&mutex);
return result;
}
/**
* gst_query_type_iterate_definitions:
*
* Get an Iterator of all the registered query types. The querytype
* definition is read only.
*
* Returns: A #GstIterator of #GstQueryTypeDefinition.
*/
GstIterator *
gst_query_type_iterate_definitions (void)
{
GstIterator *result;
g_static_mutex_lock (&mutex);
result = gst_iterator_new_list (g_static_mutex_get_mutex (&mutex),
&_n_values, &_gst_queries, NULL, NULL, NULL);
g_static_mutex_unlock (&mutex);
return result;
}
static GstQuery *
gst_query_new (GstQueryType type, GstStructure * structure)
{
GstQuery *query;
query = (GstQuery *) gst_mini_object_new (GST_TYPE_QUERY);
GST_DEBUG ("creating new query %p %d", query, type);
query->type = type;
if (structure) {
query->structure = structure;
gst_structure_set_parent_refcount (query->structure,
&query->mini_object.refcount);
} else {
query->structure = NULL;
}
return query;
}
/**
* gst_query_new_position:
* @format: the default #GstFormat for the new query
*
* Constructs a new query stream position query object. Use gst_query_unref()
* when done with it.
*
* Returns: A new #GstQuery
*/
GstQuery *
gst_query_new_position (GstFormat format)
{
GstQuery *query;
GstStructure *structure;
structure = gst_structure_new ("GstQueryPosition",
"format", GST_TYPE_FORMAT, format,
"cur", G_TYPE_INT64, (gint64) - 1,
"end", G_TYPE_INT64, (gint64) - 1, NULL);
query = gst_query_new (GST_QUERY_POSITION, structure);
return query;
}
/**
* gst_query_set_position:
* @query: the query to fill in
* @format: the requested #GstFormat
* @cur: the current position
* @end: the end position
*
* Answer a position query by setting the requested values.
*/
void
gst_query_set_position (GstQuery * query, GstFormat format,
gint64 cur, gint64 end)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_POSITION);
structure = gst_query_get_structure (query);
gst_structure_set (structure,
"format", GST_TYPE_FORMAT, format,
"cur", G_TYPE_INT64, cur, "end", G_TYPE_INT64, end, NULL);
}
/**
* gst_query_parse_position:
* @query: the query to parse
* @format: the storage for the #GstFormat of the position values
* @cur: the storage for the current position
* @end: the storage for the end position
*
* Parse a position query answer.
*/
void
gst_query_parse_position (GstQuery * query, GstFormat * format,
gint64 * cur, gint64 * end)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_POSITION);
structure = gst_query_get_structure (query);
if (format)
*format = g_value_get_enum (gst_structure_get_value (structure, "format"));
if (cur)
*cur = g_value_get_int64 (gst_structure_get_value (structure, "cur"));
if (end)
*end = g_value_get_int64 (gst_structure_get_value (structure, "end"));
}
/**
* gst_query_new_convert:
* @src_fmt: the source #GstFormat for the new query
* @value: the value to convert
* @dest_fmt: the target #GstFormat
*
* Constructs a new query convert object. Use gst_query_unref()
* when done with it.
*
* Returns: A new #GstQuery
*/
GstQuery *
gst_query_new_convert (GstFormat src_fmt, gint64 value, GstFormat dest_fmt)
{
GstQuery *query;
GstStructure *structure;
g_return_val_if_fail (value >= 0, NULL);
structure = gst_structure_new ("GstQueryConvert",
"src_format", GST_TYPE_FORMAT, src_fmt,
"src_value", G_TYPE_INT64, value,
"dest_format", GST_TYPE_FORMAT, dest_fmt,
"dest_value", G_TYPE_INT64, (gint64) - 1, NULL);
query = gst_query_new (GST_QUERY_CONVERT, structure);
return query;
}
/**
* gst_query_set_convert:
* @query: the query to fill in
* @src_format: the source #GstFormat
* @src_value: the source value
* @dest_format: the destination #GstFormat
* @dest_value: the destination value
*
* Answer a convert query by setting the requested values.
*/
void
gst_query_set_convert (GstQuery * query, GstFormat src_format, gint64 src_value,
GstFormat dest_format, gint64 dest_value)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_CONVERT);
structure = gst_query_get_structure (query);
gst_structure_set (structure,
"src_format", GST_TYPE_FORMAT, src_format,
"src_value", G_TYPE_INT64, src_value,
"dest_format", GST_TYPE_FORMAT, dest_format,
"dest_value", G_TYPE_INT64, dest_value, NULL);
}
/**
* gst_query_parse_convert:
* @query: the query to parse
* @src_format: the storage for the #GstFormat of the source value
* @src_value: the storage for the source value
* @dest_format: the storage for the #GstFormat of the destination value
* @dest_value: the storage for the destination value
*
* Parse a convert query answer.
*/
void
gst_query_parse_convert (GstQuery * query, GstFormat * src_format,
gint64 * src_value, GstFormat * dest_format, gint64 * dest_value)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_CONVERT);
structure = gst_query_get_structure (query);
if (src_format)
*src_format =
g_value_get_enum (gst_structure_get_value (structure, "src_format"));
if (src_value)
*src_value =
g_value_get_int64 (gst_structure_get_value (structure, "src_value"));
if (dest_format)
*dest_format =
g_value_get_enum (gst_structure_get_value (structure, "dest_format"));
if (dest_value)
*dest_value =
g_value_get_int64 (gst_structure_get_value (structure, "dest_value"));
}
/**
* gst_query_new_segment:
* @format: the #GstFormat for the new query
*
* Constructs a new query segment object. Use gst_query_unref()
* when done with it.
*
* Returns: A new #GstQuery
*/
GstQuery *
gst_query_new_segment (GstFormat format)
{
GstQuery *query;
GstStructure *structure;
structure = gst_structure_new ("GstQuerySegment",
"format", GST_TYPE_FORMAT, format, NULL);
query = gst_query_new (GST_QUERY_SEGMENT, structure);
return query;
}
/**
* gst_query_set_segment:
* @query: the query to fill in
* @rate: the rate of the segment
* @format: the #GstFormat of the segment values
* @start_value: the start value
* @stop_value: the stop value
* @base: the base value
*
* Answer a segment query by setting the requested values.
*/
void
gst_query_set_segment (GstQuery * query, gdouble rate, GstFormat format,
gint64 start_value, gint64 stop_value, gint64 base)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_SEGMENT);
structure = gst_query_get_structure (query);
gst_structure_set (structure,
"rate", G_TYPE_DOUBLE, rate,
"format", GST_TYPE_FORMAT, format,
"start_value", G_TYPE_INT64, start_value,
"stop_value", G_TYPE_INT64, stop_value, "base", G_TYPE_INT64, base, NULL);
}
/**
* gst_query_parse_segment:
* @query: the query to parse
* @rate: the storage for the rate of the segment
* @format: the storage for the #GstFormat of the values
* @start_value: the storage for the start value
* @stop_value: the storage for the stop value
* @base: the storage for the base value
*
* Parse a segment query answer.
*/
void
gst_query_parse_segment (GstQuery * query, gdouble * rate, GstFormat * format,
gint64 * start_value, gint64 * stop_value, gint64 * base)
{
GstStructure *structure;
g_return_if_fail (GST_QUERY_TYPE (query) == GST_QUERY_SEGMENT);
structure = gst_query_get_structure (query);
if (rate)
*rate = g_value_get_double (gst_structure_get_value (structure, "rate"));
if (format)
*format = g_value_get_enum (gst_structure_get_value (structure, "format"));
if (start_value)
*start_value =
g_value_get_int64 (gst_structure_get_value (structure, "start_value"));
if (stop_value)
*stop_value =
g_value_get_int64 (gst_structure_get_value (structure, "stop_value"));
if (base)
*base = g_value_get_int64 (gst_structure_get_value (structure, "base"));
}
/**
* gst_query_new_application:
* @type: the query type
* @structure: a structure for the query
*
* Constructs a new custom application query object. Use gst_query_unref()
* when done with it.
*
* Returns: A new #GstQuery
*/
GstQuery *
gst_query_new_application (GstQueryType type, GstStructure * structure)
{
g_return_val_if_fail (gst_query_type_get_details (type) != NULL, NULL);
g_return_val_if_fail (structure != NULL, NULL);
return gst_query_new (type, structure);
}
/**
* gst_query_get_structure:
* @query: the query to parse
*
* Get the structure of a query.
*
* Returns: The #GstStructure of the query. The structure is still owned
* by the query and will therefore be freed when the query is unreffed.
*/
GstStructure *
gst_query_get_structure (GstQuery * query)
{
g_return_val_if_fail (GST_IS_QUERY (query), NULL);
return query->structure;
}