gstreamer/gst/gstelement.h
Wim Taymans a56bdf2768 Fix docs, move some STATE macros to private.
Original commit message from CVS:
* docs/gst/gstreamer-sections.txt:
* gst/gstelement.c:
* gst/gstelement.h:
Fix docs, move some STATE macros to private.
2005-11-10 11:17:26 +00:00

599 lines
22 KiB
C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000,2004 Wim Taymans <wim@fluendo.com>
*
* gstelement.h: Header for GstElement
*
* 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.
*/
#ifndef __GST_ELEMENT_H__
#define __GST_ELEMENT_H__
/* gstelement.h and gstelementfactory.h include eachother */
typedef struct _GstElement GstElement;
typedef struct _GstElementClass GstElementClass;
/* gstmessage.h needs State */
/**
* GstState:
* @GST_STATE_VOID_PENDING : no pending state.
* @GST_STATE_NULL : the NULL state or initial state of an element
* @GST_STATE_READY : the element is ready to go to PAUSED
* @GST_STATE_PAUSED : the element is PAUSED
* @GST_STATE_PLAYING : the element is PLAYING
*
* The posible states an element can be in.
*/
typedef enum {
GST_STATE_VOID_PENDING = 0,
GST_STATE_NULL = 1,
GST_STATE_READY = 2,
GST_STATE_PAUSED = 3,
GST_STATE_PLAYING = 4
} GstState;
#include <gst/gstconfig.h>
#include <gst/gstobject.h>
#include <gst/gstpad.h>
#include <gst/gstbus.h>
#include <gst/gstclock.h>
#include <gst/gstelementfactory.h>
#include <gst/gstplugin.h>
#include <gst/gstpluginfeature.h>
#include <gst/gstindex.h>
#include <gst/gstindexfactory.h>
#include <gst/gstiterator.h>
#include <gst/gstmessage.h>
#include <gst/gsttaglist.h>
G_BEGIN_DECLS
#define GST_TYPE_ELEMENT (gst_element_get_type ())
#define GST_IS_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_ELEMENT))
#define GST_IS_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_ELEMENT))
#define GST_ELEMENT_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_ELEMENT, GstElementClass))
#define GST_ELEMENT(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_ELEMENT, GstElement))
#define GST_ELEMENT_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_ELEMENT, GstElementClass))
#define GST_ELEMENT_CAST(obj) ((GstElement*)(obj))
/**
* GstStateChangeReturn:
* @GST_STATE_CHANGE_FAILURE : the state change failed
* @GST_STATE_CHANGE_SUCCESS : the state change succeeded
* @GST_STATE_CHANGE_ASYNC : the state change will happen asynchronously
* @GST_STATE_CHANGE_NO_PREROLL: the state change cannot be prerolled
*
* the possible return values from a state change function.
*/
typedef enum {
GST_STATE_CHANGE_FAILURE = 0,
GST_STATE_CHANGE_SUCCESS = 1,
GST_STATE_CHANGE_ASYNC = 2,
GST_STATE_CHANGE_NO_PREROLL = 3
} GstStateChangeReturn;
/* NOTE: this probably should be done with an #ifdef to decide
* whether to safe-cast or to just do the non-checking cast.
*/
/**
* GST_STATE:
* @elem: a #GstElement to return state for.
*
* This macro returns the current #GstState of the element.
*/
#define GST_STATE(elem) (GST_ELEMENT_CAST(elem)->current_state)
/**
* GST_STATE_NEXT:
* @elem: a #GstElement to return the next state for.
*
* This macro returns the next #GstState of the element.
*/
#define GST_STATE_NEXT(elem) (GST_ELEMENT_CAST(elem)->next_state)
/**
* GST_STATE_PENDING:
* @elem: a #GstElement to return the pending state for.
*
* This macro returns the currently pending #GstState of the element.
*/
#define GST_STATE_PENDING(elem) (GST_ELEMENT_CAST(elem)->pending_state)
/**
* GST_STATE_RETURN:
* @elem: a #GstElement to return the last state result for.
*
* This macro returns the last #GstStateChangeReturn value.
*/
#define GST_STATE_RETURN(elem) (GST_ELEMENT_CAST(elem)->last_return)
#define __GST_SIGN(val) ((val) < 0 ? -1 : ((val) > 0 ? 1 : 0))
/**
* GST_STATE_GET_NEXT:
* @cur: A starting #GstState
* @pending: A target #GstState
*
* Given a current state @cur and a target state @pending, calculate the next (intermediate)
* #GstState.
*/
#define GST_STATE_GET_NEXT(cur,pending) ((cur) + __GST_SIGN ((gint)(pending) - (gint)(cur)))
/**
* GST_STATE_TRANSITION:
* @cur: A current state
* @next: A next state
*
* Given a current state @cur and a next state @next, calculate the associated
* #GstStateChange transition.
*/
#define GST_STATE_TRANSITION(cur,next) (((cur)<<3)|(next))
/**
* GST_STATE_TRANSITION_CURRENT:
* @trans: A #GstStateChange
*
* Given a state transition @trans, extract the current #GstState.
*/
#define GST_STATE_TRANSITION_CURRENT(trans) ((trans)>>3)
/**
* GST_STATE_TRANSITION_NEXT:
* @trans: A #GstStateChange
*
* Given a state transition @trans, extract the next #GstState.
*/
#define GST_STATE_TRANSITION_NEXT(trans) ((trans)&0x7)
/**
* GstStateChange:
* @GST_STATE_CHANGE_NULL_TO_READY : state change from NULL to READY
* @GST_STATE_CHANGE_READY_TO_PAUSED : state change from READY to PAUSED
* @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING
* @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED
* @GST_STATE_CHANGE_PAUSED_TO_READY : state change from PAUSED to READY
* @GST_STATE_CHANGE_READY_TO_NULL : state change from READY to NULL
*
* The different (interesting) state changes that are passed to the
* state change functions of elements.
*/
typedef enum /*< flags=0 >*/
{
GST_STATE_CHANGE_NULL_TO_READY = (GST_STATE_NULL<<3) | GST_STATE_READY,
GST_STATE_CHANGE_READY_TO_PAUSED = (GST_STATE_READY<<3) | GST_STATE_PAUSED,
GST_STATE_CHANGE_PAUSED_TO_PLAYING = (GST_STATE_PAUSED<<3) | GST_STATE_PLAYING,
GST_STATE_CHANGE_PLAYING_TO_PAUSED = (GST_STATE_PLAYING<<3) | GST_STATE_PAUSED,
GST_STATE_CHANGE_PAUSED_TO_READY = (GST_STATE_PAUSED<<3) | GST_STATE_READY,
GST_STATE_CHANGE_READY_TO_NULL = (GST_STATE_READY<<3) | GST_STATE_NULL
} GstStateChange;
/**
* GstElementFlags:
* @GST_ELEMENT_LOCKED_STATE: ignore state changes from parent
* @GST_ELEMENT_IS_SINK: the element is a sink
* @GST_ELEMENT_UNPARENTING: Child is being removed from the parent bin.
* gst_bin_remove() on a child already being removed immediately returns FALSE
* @GST_ELEMENT_FLAG_LAST: offset to define more flags
*
* The standard flags that an element may have.
*/
typedef enum
{
GST_ELEMENT_LOCKED_STATE = (GST_OBJECT_FLAG_LAST << 0),
GST_ELEMENT_IS_SINK = (GST_OBJECT_FLAG_LAST << 1),
GST_ELEMENT_UNPARENTING = (GST_OBJECT_FLAG_LAST << 2),
/* padding */
GST_ELEMENT_FLAG_LAST = (GST_OBJECT_FLAG_LAST << 16)
} GstElementFlags;
/**
* GST_ELEMENT_IS_LOCKED_STATE:
* @elem: A #GstElement to query
*
* Check if the element is in the locked state and therefore will ignore state
* changes from its parent object.
*/
#define GST_ELEMENT_IS_LOCKED_STATE(elem) (GST_OBJECT_FLAG_IS_SET(elem,GST_ELEMENT_LOCKED_STATE))
/**
* GST_ELEMENT_NAME:
* @elem: A #GstElement to query
*
* Gets the name of this element. Use only in core as this is not
* ABI-compatible. Others use gst_element_get_name()
*/
#define GST_ELEMENT_NAME(elem) (GST_OBJECT_NAME(elem))
/**
* GST_ELEMENT_PARENT:
* @elem: A #GstElement to query
*
* Get the parent object of this element.
*/
#define GST_ELEMENT_PARENT(elem) (GST_ELEMENT_CAST(GST_OBJECT_PARENT(elem)))
/**
* GST_ELEMENT_BUS:
* @elem: A #GstElement to query
*
* Get the message bus of this element.
*/
#define GST_ELEMENT_BUS(elem) (GST_ELEMENT_CAST(elem)->bus)
/**
* GST_ELEMENT_CLOCK:
* @elem: A #GstElement to query
*
* Get the clock of this element
*/
#define GST_ELEMENT_CLOCK(elem) (GST_ELEMENT_CAST(elem)->clock)
/**
* GST_ELEMENT_PADS:
* @elem: A #GstElement to query
*
* Get the pads of this elements.
*/
#define GST_ELEMENT_PADS(elem) (GST_ELEMENT_CAST(elem)->pads)
/**
* GST_ELEMENT_ERROR:
* @el: the element that throws the error
* @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #GstGError)
* @code: error code defined for that domain (see #GstGError)
* @text: the message to display (format string and args enclosed in
parentheses)
* @debug: debugging information for the message (format string and args
enclosed in parentheses)
*
* Utility function that elements can use in case they encountered a fatal
* data processing error. The pipeline will throw an error signal and the
* application will be requested to stop further media processing.
*/
#define GST_ELEMENT_ERROR(el, domain, code, text, debug) \
G_STMT_START { \
gchar *__txt = _gst_element_error_printf text; \
gchar *__dbg = _gst_element_error_printf debug; \
if (__txt) \
GST_WARNING_OBJECT (el, "error: %s", __txt); \
if (__dbg) \
GST_WARNING_OBJECT (el, "error: %s", __dbg); \
gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_ERROR, \
GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code, \
__txt, __dbg, __FILE__, GST_FUNCTION, __LINE__); \
} G_STMT_END
/**
* GST_ELEMENT_WARNING:
* @el: the element that throws the error
* @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #GstGError)
* @code: error code defined for that domain (see #GstGError)
* @text: the message to display (format string and args enclosed in
parentheses)
* @debug: debugging information for the message (format string and args
enclosed in parentheses)
*
* Utility function that elements can use in case they encountered a non-fatal
* data processing problem. The pipeline will throw a warning signal and the
* application will be informed.
*/
#define GST_ELEMENT_WARNING(el, domain, code, text, debug) \
G_STMT_START { \
gchar *__txt = _gst_element_error_printf text; \
gchar *__dbg = _gst_element_error_printf debug; \
if (__txt) \
GST_WARNING_OBJECT (el, "warning: %s", __txt); \
if (__dbg) \
GST_WARNING_OBJECT (el, "warning: %s", __dbg); \
gst_element_message_full (GST_ELEMENT(el), GST_MESSAGE_WARNING, \
GST_ ## domain ## _ERROR, GST_ ## domain ## _ERROR_ ## code, \
__txt, __dbg, __FILE__, GST_FUNCTION, __LINE__); \
} G_STMT_END
/* the state change mutexes and conds */
/**
* GST_STATE_GET_LOCK:
* @elem: a #GstElement
*
* Get a reference to the state lock of @elem.
* This lock is used by the core. It is taken while getting or setting
* the state, during state changes, and while finalizing.
*/
#define GST_STATE_GET_LOCK(elem) (GST_ELEMENT_CAST(elem)->state_lock)
/**
* GST_STATE_GET_COND:
* @elem: a #GstElement
*
* Get the conditional used to signal the completion of a state change.
*/
#define GST_STATE_GET_COND(elem) (GST_ELEMENT_CAST(elem)->state_cond)
#define GST_STATE_LOCK(elem) g_static_rec_mutex_lock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_TRYLOCK(elem) g_static_rec_mutex_trylock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_UNLOCK(elem) g_static_rec_mutex_unlock(GST_STATE_GET_LOCK(elem))
#define GST_STATE_UNLOCK_FULL(elem) g_static_rec_mutex_unlock_full(GST_STATE_GET_LOCK(elem))
#define GST_STATE_LOCK_FULL(elem,t) g_static_rec_mutex_lock_full(GST_STATE_GET_LOCK(elem), t)
#define GST_STATE_WAIT(elem) g_cond_wait (GST_STATE_GET_COND (elem), \
GST_GET_LOCK (elem))
#define GST_STATE_TIMED_WAIT(elem, timeval) g_cond_timed_wait (GST_STATE_GET_COND (elem), \
GST_GET_LOCK (elem), timeval)
#define GST_STATE_SIGNAL(elem) g_cond_signal (GST_STATE_GET_COND (elem));
#define GST_STATE_BROADCAST(elem) g_cond_broadcast (GST_STATE_GET_COND (elem));
/**
* GstElement:
* @state_lock: Used to serialize execution of gst_element_set_state()
* @state_cond: Used to signal completion of a state change
* @state_cookie: Used to detect concurrent execution of gst_element_set_state() and
* gst_element_get_state()
* @current_state: the current state of an element
* @next_state: the next state of an element, can be #GST_STATE_VOID_PENDING if the
* element is in the correct state.
* @pending_state: the final state the element should go to, can be #GST_STATE_VOID_PENDING
* if the element is in the correct state
* @last_return: the last return value of an element state change
* @bus: the bus of the element. This bus is provided to the element by the parent element
* or the application. A #GstPipeline has a bus of its own.
* @clock: the clock of the element. This clock is usually provided by to the element by
* the toplevel #GstPipeline.
* @base_time: the time of the clock right before the element is set to PLAYING. Subtracting
* @base_time from the current clock time in the PLAYING state will yield the stream time.
* @numpads: number of pads of the element, includes both source and sink pads.
* @pads: list of pads
* @numsrcpads: number of source pads of the element.
* @srcpads: list of source pads
* @numsinkpads: number of sink pads of the element.
* @sinkpads: list of sink pads
* @pads_cookie: updated whenever the a pad is added or removed
*
* GStreamer element abstract base class.
*/
struct _GstElement
{
GstObject object;
/*< public >*/ /* with LOCK */
GStaticRecMutex *state_lock;
/* element state */
GCond *state_cond;
guint32 state_cookie;
GstState current_state;
GstState next_state;
GstState pending_state;
GstStateChangeReturn last_return;
GstBus *bus;
/* allocated clock */
GstClock *clock;
GstClockTimeDiff base_time; /* NULL/READY: 0 - PAUSED: current time - PLAYING: difference to clock */
/* element pads, these lists can only be iterated while holding
* the LOCK or checking the cookie after each LOCK. */
guint16 numpads;
GList *pads;
guint16 numsrcpads;
GList *srcpads;
guint16 numsinkpads;
GList *sinkpads;
guint32 pads_cookie;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
/**
* GstElementClass:
* @parent_class: the parent class structure
* @details: #GstElementDetails for elements of this class
* @elementfactory: the #GstElementFactory that creates these elements
* @padtemplates: a #GList of #GstPadTemplate
* @numpadtemplates: the number of padtemplates
* @pad_templ_cookie: changed whenever the padtemplates change
* @request_new_pad: called when a new pad is requested
* @release_pad: called when a request pad is to be released
* @get_state: get the state of the element
* @set_state: set a new state on the element
* @change_state: called by @set_state to perform an incremental state change
* @set_bus: set a #GstBus on the element
* @provide_clock: gets the #GstClock provided by the element
* @set_clock: set the #GstClock on the element
* @get_index: set a #GstIndex on the element
* @set_index: get the #GstIndex of an element
* @send_event: send a #GstEvent to the element
* @get_query_types: get the supported #GstQueryType of this element
* @query: perform a #GstQuery on the element
*
* GStreamer element class. Override the vmethods to implement the element
* functionality.
*/
struct _GstElementClass
{
GstObjectClass parent_class;
/*< public >*/
/* the element details */
GstElementDetails details;
/* factory that the element was created from */
GstElementFactory *elementfactory;
/* templates for our pads */
GList *padtemplates;
gint numpadtemplates;
guint32 pad_templ_cookie;
/*< private >*/
/* signal callbacks */
void (*state_changed) (GstElement *element, GstState old, GstState state); /* FIXME, ABI unused */
void (*pad_added) (GstElement *element, GstPad *pad);
void (*pad_removed) (GstElement *element, GstPad *pad);
void (*no_more_pads) (GstElement *element);
/*< public >*/
/* virtual methods for subclasses */
/* request/release pads */
GstPad* (*request_new_pad) (GstElement *element, GstPadTemplate *templ, const gchar* name);
void (*release_pad) (GstElement *element, GstPad *pad);
/* state changes */
GstStateChangeReturn (*get_state) (GstElement * element, GstState * state,
GstState * pending, GstClockTime timeout);
GstStateChangeReturn (*set_state) (GstElement *element, GstState state);
GstStateChangeReturn (*change_state) (GstElement *element, GstStateChange transition);
/* bus */
void (*set_bus) (GstElement * element, GstBus * bus);
/* set/get clocks */
GstClock* (*provide_clock) (GstElement *element);
void (*set_clock) (GstElement *element, GstClock *clock);
/* index */
GstIndex* (*get_index) (GstElement *element);
void (*set_index) (GstElement *element, GstIndex *index);
/* query functions */
gboolean (*send_event) (GstElement *element, GstEvent *event);
const GstQueryType* (*get_query_types) (GstElement *element);
gboolean (*query) (GstElement *element, GstQuery *query);
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
/* element class pad templates */
void gst_element_class_add_pad_template (GstElementClass *klass, GstPadTemplate *templ);
GstPadTemplate* gst_element_class_get_pad_template (GstElementClass *element_class, const gchar *name);
GList* gst_element_class_get_pad_template_list (GstElementClass *element_class);
void gst_element_class_set_details (GstElementClass *klass,
const GstElementDetails *details);
/* element instance */
GType gst_element_get_type (void);
/* basic name and parentage stuff from GstObject */
/**
* gst_element_get_name:
* @elem: a #GstElement to set the name of.
*
* Gets the name of the element.
*/
#define gst_element_get_name(elem) gst_object_get_name(GST_OBJECT_CAST(elem))
/**
* gst_element_set_name:
* @elem: a #GstElement to set the name of.
* @name: the new name
*
* Sets the name of the element, getting rid of the old name if there was one.
*/
#define gst_element_set_name(elem,name) gst_object_set_name(GST_OBJECT_CAST(elem),name)
/**
* gst_element_get_parent:
* @elem: a #GstElement to get the parent of.
*
* Gets the parent of an element.
*/
#define gst_element_get_parent(elem) gst_object_get_parent(GST_OBJECT_CAST(elem))
/**
* gst_element_set_parent:
* @elem: a #GstElement to set the parent of.
* @parent: the new parent #GstObject of the element.
*
* Sets the parent of an element.
*/
#define gst_element_set_parent(elem,parent) gst_object_set_parent(GST_OBJECT_CAST(elem),parent)
/* clocking */
gboolean gst_element_requires_clock (GstElement *element);
gboolean gst_element_provides_clock (GstElement *element);
GstClock* gst_element_provide_clock (GstElement *element);
GstClock* gst_element_get_clock (GstElement *element);
void gst_element_set_clock (GstElement *element, GstClock *clock);
void gst_element_set_base_time (GstElement *element, GstClockTime time);
GstClockTime gst_element_get_base_time (GstElement *element);
/* indexes */
gboolean gst_element_is_indexable (GstElement *element);
void gst_element_set_index (GstElement *element, GstIndex *index);
GstIndex* gst_element_get_index (GstElement *element);
/* bus */
void gst_element_set_bus (GstElement * element, GstBus * bus);
GstBus * gst_element_get_bus (GstElement * element);
/* pad management */
gboolean gst_element_add_pad (GstElement *element, GstPad *pad);
gboolean gst_element_remove_pad (GstElement *element, GstPad *pad);
void gst_element_no_more_pads (GstElement *element);
GstPad* gst_element_get_pad (GstElement *element, const gchar *name);
GstPad* gst_element_get_static_pad (GstElement *element, const gchar *name);
GstPad* gst_element_get_request_pad (GstElement *element, const gchar *name);
void gst_element_release_request_pad (GstElement *element, GstPad *pad);
GstIterator * gst_element_iterate_pads (GstElement * element);
GstIterator * gst_element_iterate_src_pads (GstElement * element);
GstIterator * gst_element_iterate_sink_pads (GstElement * element);
/* event/query/format stuff */
gboolean gst_element_send_event (GstElement *element, GstEvent *event);
gboolean gst_element_seek (GstElement *element, gdouble rate,
GstFormat format, GstSeekFlags flags,
GstSeekType cur_type, gint64 cur,
GstSeekType stop_type, gint64 stop);
G_CONST_RETURN GstQueryType*
gst_element_get_query_types (GstElement *element);
gboolean gst_element_query (GstElement *element, GstQuery *query);
/* messages */
gboolean gst_element_post_message (GstElement * element, GstMessage * message);
/* error handling */
gchar * _gst_element_error_printf (const gchar *format, ...);
void gst_element_message_full (GstElement * element, GstMessageType type,
GQuark domain, gint code, gchar * text,
gchar * debug, const gchar * file,
const gchar * function, gint line);
/* state management */
gboolean gst_element_is_locked_state (GstElement *element);
gboolean gst_element_set_locked_state (GstElement *element, gboolean locked_state);
gboolean gst_element_sync_state_with_parent (GstElement *element);
GstStateChangeReturn gst_element_get_state (GstElement * element,
GstState * state,
GstState * pending,
GstClockTime timeout);
GstStateChangeReturn gst_element_set_state (GstElement *element, GstState state);
void gst_element_abort_state (GstElement * element);
GstStateChangeReturn gst_element_commit_state (GstElement * element);
void gst_element_lost_state (GstElement * element);
/* factory management */
GstElementFactory* gst_element_get_factory (GstElement *element);
G_END_DECLS
#endif /* __GST_ELEMENT_H__ */