gstreamer/gst/gstpad.h

/* GStreamer
 * Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
 *                    2000 Wim Taymans <wim.taymans@chello.be>
 *
 * gstpad.h: Header for GstPad object
 *
 * 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_PAD_H__
#define __GST_PAD_H__

#include <gst/gstconfig.h>

#include <gst/gstobject.h>
#include <gst/gstbuffer.h>
#include <gst/gstcaps.h>
#include <gst/gstevent.h>
#include <gst/gstquery.h>
#include <gst/gsttask.h>

G_BEGIN_DECLS

/*
 * Pad base class
 */
#define GST_TYPE_PAD			(gst_pad_get_type ())
#define GST_IS_PAD(obj)			(G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_PAD))
#define GST_IS_PAD_FAST(obj)		(G_OBJECT_TYPE(obj) == GST_TYPE_PAD) /* necessary? */
#define GST_IS_PAD_CLASS(klass)		(G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_PAD))
#define GST_PAD(obj)			(G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_PAD, GstPad))
#define GST_PAD_CLASS(klass)		(G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_PAD, GstPadClass))
#define GST_PAD_CAST(obj)		((GstPad*)(obj))

typedef struct _GstPad GstPad;
typedef struct _GstPadClass GstPadClass;

/**
 * GstPadLinkReturn:
 * @GST_PAD_LINK_OK		: link succeeded
 * @GST_PAD_LINK_WRONG_HIERARCHY: pads have no common grandparent
 * @GST_PAD_LINK_WAS_LINKED	: pad was already linked
 * @GST_PAD_LINK_WRONG_DIRECTION: pads have wrong direction
 * @GST_PAD_LINK_NOFORMAT	: pads do not have common format
 * @GST_PAD_LINK_NOSCHED	: pads cannot cooperate in scheduling
 * @GST_PAD_LINK_REFUSED	: refused for some reason
 */
typedef enum {
  GST_PAD_LINK_OK               =  0,
  GST_PAD_LINK_WRONG_HIERARCHY  = -1,
  GST_PAD_LINK_WAS_LINKED       = -2,
  GST_PAD_LINK_WRONG_DIRECTION  = -3,
  GST_PAD_LINK_NOFORMAT         = -4,
  GST_PAD_LINK_NOSCHED          = -5,
  GST_PAD_LINK_REFUSED          = -6,
} GstPadLinkReturn;

/**
 * GST_PAD_LINK_FAILED:
 * @ret: the #GstPadLinkReturn value
 *
 * Macro to test if the given #GstPadLinkReturn value indicates a failed
 * link step.
 */
#define GST_PAD_LINK_FAILED(ret) ((ret) < GST_PAD_LINK_OK)

/**
 * GST_PAD_LINK_SUCCESSFUL:
 * @ret: the #GstPadLinkReturn value
 *
 * Macro to test if the given #GstPadLinkReturn value indicates a successful
 * link step.
 */
#define GST_PAD_LINK_SUCCESSFUL(ret) ((ret) >= GST_PAD_LINK_OK)

/**
 * GstFlowReturn:
 * @GST_FLOW_RESEND:	  	 Resend buffer, possibly with new caps.
 * @GST_FLOW_OK:		 Data passing was ok.
 * @GST_FLOW_NOT_LINKED:     	 Pad is not linked.
 * @GST_FLOW_WRONG_STATE:    	 Pad is in wrong state.
 * @GST_FLOW_UNEXPECTED:     	 Did not expect anything, like after EOS.
 * @GST_FLOW_NOT_NEGOTIATED: 	 Pad is not negotiated.
 * @GST_FLOW_ERROR:	  	 Some (fatal) error occured.
 *
 * The result of passing data to a linked pad.
 */
typedef enum {
  GST_FLOW_RESEND	  =  1,
  GST_FLOW_OK		  =  0,
  /* expected failures */
  GST_FLOW_NOT_LINKED     = -1,
  GST_FLOW_WRONG_STATE    = -2,
  /* error cases */
  GST_FLOW_UNEXPECTED     = -3,
  GST_FLOW_NOT_NEGOTIATED = -4,
  GST_FLOW_ERROR	  = -5,
  GST_FLOW_NOT_SUPPORTED  = -6
} GstFlowReturn;

/**
 * GST_FLOW_IS_FATAL:
 * @ret: a #GstFlowReturn value
 *
 * Macro to test if the given #GstFlowReturn value indicates a fatal
 * error.
 */
#define GST_FLOW_IS_FATAL(ret) ((ret) <= GST_FLOW_UNEXPECTED)

G_CONST_RETURN gchar*	gst_flow_get_name	(GstFlowReturn ret);
GQuark			gst_flow_to_quark	(GstFlowReturn ret);

typedef enum {
  GST_ACTIVATE_NONE,
  GST_ACTIVATE_PUSH,
  GST_ACTIVATE_PULL,
} GstActivateMode;

#define GST_PAD_MODE_ACTIVATE(mode) ((mode) != GST_ACTIVATE_NONE)

/* pad states */
typedef gboolean		(*GstPadActivateFunction)	(GstPad *pad);
typedef gboolean		(*GstPadActivateModeFunction)	(GstPad *pad, gboolean active);


/* data passing */
/**
 * GstPadChainFunction:
 * @pad: the #GstPad that performed the chain.
 * @buffer: the #GstBuffer that is chained.
 *
 * A function that will be called when chaining buffers.
 *
 *  Returns: GST_FLOW_OK for success
 */
typedef GstFlowReturn		(*GstPadChainFunction)		(GstPad *pad, GstBuffer *buffer);
typedef GstFlowReturn		(*GstPadGetRangeFunction)	(GstPad *pad, guint64 offset,
		                                                 guint length, GstBuffer **buffer);

/**
 * GstPadEventFunction:
 * @pad: the #GstPad to handle the event.
 * @event: the #GstEvent to handle.
 *
 * Function signature to handle an event for the pad.
 *
 * Returns: TRUE if the pad could handle the event.
 */
typedef gboolean		(*GstPadEventFunction)		(GstPad *pad, GstEvent *event);


/* deprecate me, check range should use seeking query */
typedef gboolean		(*GstPadCheckGetRangeFunction)	(GstPad *pad);


/* internal links */
/**
 * GstPadIntLinkFunction:
 * @pad: The #GstPad to query.
 *
 * The signature of the internal pad link function.
 *
 * Returns: a newly allocated #GList of pads that are linked to the given pad on
 *  the inside of the parent element.
 *  The caller must call g_list_free() on it after use.
 *
 */
typedef GList*			(*GstPadIntLinkFunction)	(GstPad *pad);


/* generic query function */
/**
 * GstPadQueryTypeFunction:
 * @pad: a #GstPad to query
 *
 * The signature of the query types function.
 *
 * Returns: an array of query types
 */
typedef const GstQueryType*	(*GstPadQueryTypeFunction)	(GstPad *pad);

/**
 * GstPadQueryFunction:
 * @pad: the #GstPad to query.
 * @query: the #GstQuery object to execute
 *
 * The signature of the query function.
 *
 * Returns: TRUE if the query could be performed.
 */
typedef gboolean		(*GstPadQueryFunction)		(GstPad *pad, GstQuery *query);


/* linking */
/**
 * GstPadLinkFunction
 * @pad: the #GstPad that is linked.
 * @peer: the peer #GstPad of the link
 *
 * Function signature to handle a new link on the pad.
 *
 * Returns: the result of the link with the specified peer.
 */
typedef GstPadLinkReturn	(*GstPadLinkFunction)		(GstPad *pad, GstPad *peer);
/**
 * GstPadUnlinkFunction
 * @pad: the #GstPad that is linked.
 *
 * Function signature to handle a unlinking the pad prom its peer.
 */
typedef void			(*GstPadUnlinkFunction)		(GstPad *pad);


/* caps nego */
/**
 * GstPadGetCapsFunction:
 * @pad: the #GstPad to get the capabilities of.
 *
 * Returns a copy of the capabilities of the specified pad. By default this
 * function will return the pad template capabilities, but can optionally
 * be overridden.
 *
 * Returns: a newly allocated copy #GstCaps of the pad.
 */
typedef GstCaps*		(*GstPadGetCapsFunction)	(GstPad *pad);
typedef gboolean		(*GstPadSetCapsFunction)	(GstPad *pad, GstCaps *caps);
typedef gboolean		(*GstPadAcceptCapsFunction)	(GstPad *pad, GstCaps *caps);
typedef void			(*GstPadFixateCapsFunction)	(GstPad *pad, GstCaps *caps);
typedef GstFlowReturn		(*GstPadBufferAllocFunction)	(GstPad *pad, guint64 offset, guint size,
								 GstCaps *caps, GstBuffer **buf);

/* misc */
/**
 * GstPadDispatcherFunction:
 * @pad: the #GstPad that is dispatched.
 * @data: the gpointer to optional user data.
 *
 * A dispatcher function is called for all internally linked pads, see
 * gst_pad_dispatcher().
 *
 * Returns: TRUE if the dispatching procedure has to be stopped.
 */
typedef gboolean		(*GstPadDispatcherFunction)	(GstPad *pad, gpointer data);

/**
 * GstPadBlockCallback:
 * @pad: the #GstPad that is blockend or unblocked.
 * @blocked: blocking state for the pad
 * @user_data: the gpointer to optional user data.
 *
 * Callback used by gst_pad_set_blocked_async(). Gets called when the blocking
 * operation succeeds.
 */

typedef void			(*GstPadBlockCallback)		(GstPad *pad, gboolean blocked, gpointer user_data);

/**
 * GstPadDirection:
 * @GST_PAD_UNKNOWN: direction is unknown.
 * @GST_PAD_SRC: the pad is a source pad.
 * @GST_PAD_SINK: the pad is a sink pad.
 *
 * The direction of a pad.
 */
typedef enum {
  GST_PAD_UNKNOWN,
  GST_PAD_SRC,
  GST_PAD_SINK
} GstPadDirection;

/**
 * GstPadFlags:
 * @GST_PAD_BLOCKED: is dataflow on a pad blocked
 * @GST_PAD_FLUSHING: is pad empying buffers
 * @GST_PAD_IN_GETCAPS: GstPadGetCapsFunction() is running now
 * @GST_PAD_IN_SETCAPS: GstPadSetCapsFunction() is running now
 * @GST_PAD_FLAG_LAST: offset to define more flags
 *
 * Pad state flags
 */
typedef enum {
  GST_PAD_BLOCKED       = (GST_OBJECT_FLAG_LAST << 0),
  GST_PAD_FLUSHING      = (GST_OBJECT_FLAG_LAST << 1),
  GST_PAD_IN_GETCAPS    = (GST_OBJECT_FLAG_LAST << 2),
  GST_PAD_IN_SETCAPS    = (GST_OBJECT_FLAG_LAST << 3),
  /* padding */
  GST_PAD_FLAG_LAST     = (GST_OBJECT_FLAG_LAST << 8)
} GstPadFlags;

/* FIXME: this awful circular dependency need to be resolved properly (see padtemplate.h) */
typedef struct _GstPadTemplate GstPadTemplate;

struct _GstPad {
  GstObject			object;

  gpointer			element_private;

  GstPadTemplate		*padtemplate;

  /* direction cannot change after creating the pad */
  GstPadDirection		 direction;

  /*< public >*/ /* with STREAM_LOCK */
  /* streaming rec_lock */
  GStaticRecMutex		*stream_rec_lock;
  GstTask			*task;
  /*< public >*/ /* with PREROLL_LOCK */
  GMutex			*preroll_lock;
  GCond				*preroll_cond;

  /*< public >*/ /* with LOCK */
  /* block cond, mutex is from the object */
  GCond				*block_cond;
  GstPadBlockCallback		 block_callback;
  gpointer			 block_data;

  /* the pad capabilities */
  GstCaps			*caps;
  GstPadGetCapsFunction		getcapsfunc;
  GstPadSetCapsFunction		setcapsfunc;
  GstPadAcceptCapsFunction	 acceptcapsfunc;
  GstPadFixateCapsFunction	 fixatecapsfunc;

  GstPadActivateFunction	 activatefunc;
  GstPadActivateModeFunction	 activatepushfunc;
  GstPadActivateModeFunction	 activatepullfunc;

  /* pad link */
  GstPadLinkFunction		 linkfunc;
  GstPadUnlinkFunction		 unlinkfunc;
  GstPad			*peer;

  gpointer			 sched_private;

  /* data transport functions */
  GstPadChainFunction		 chainfunc;
  GstPadCheckGetRangeFunction	 checkgetrangefunc;
  GstPadGetRangeFunction	 getrangefunc;
  GstPadEventFunction		 eventfunc;

  GstActivateMode		 mode;

  /* generic query method */
  GstPadQueryTypeFunction	 querytypefunc;
  GstPadQueryFunction		 queryfunc;

  /* internal links */
  GstPadIntLinkFunction		 intlinkfunc;

  GstPadBufferAllocFunction      bufferallocfunc;

  /* whether to emit signals for have-data. counts number
   * of handlers attached. */
  gint				 do_buffer_signals;
  gint				 do_event_signals;

  /*< private >*/
  gpointer _gst_reserved[GST_PADDING];
};

struct _GstPadClass {
  GstObjectClass	parent_class;

  /* signal callbacks */
  void		(*linked)		(GstPad *pad, GstPad *peer);
  void		(*unlinked)		(GstPad *pad, GstPad *peer);
  void		(*request_link)		(GstPad *pad);
  gboolean	(*have_data)		(GstPad *pad, GstMiniObject *data);

  /*< private >*/
  gpointer _gst_reserved[GST_PADDING];
};


/***** helper macros *****/
/* GstPad */
#define GST_PAD_NAME(pad)		(GST_OBJECT_NAME(pad))
#define GST_PAD_PARENT(pad)		(GST_ELEMENT_CAST(GST_OBJECT_PARENT(pad)))
#define GST_PAD_ELEMENT_PRIVATE(pad)	(GST_PAD_CAST(pad)->element_private)
#define GST_PAD_PAD_TEMPLATE(pad)	(GST_PAD_CAST(pad)->padtemplate)
#define GST_PAD_DIRECTION(pad)		(GST_PAD_CAST(pad)->direction)
#define GST_PAD_TASK(pad)		(GST_PAD_CAST(pad)->task)
#define GST_PAD_ACTIVATE_MODE(pad)	(GST_PAD_CAST(pad)->mode)

#define GST_PAD_ACTIVATEFUNC(pad)	(GST_PAD_CAST(pad)->activatefunc)
#define GST_PAD_ACTIVATEPUSHFUNC(pad)	(GST_PAD_CAST(pad)->activatepushfunc)
#define GST_PAD_ACTIVATEPULLFUNC(pad)	(GST_PAD_CAST(pad)->activatepullfunc)
#define GST_PAD_CHAINFUNC(pad)		(GST_PAD_CAST(pad)->chainfunc)
#define GST_PAD_CHECKGETRANGEFUNC(pad)	(GST_PAD_CAST(pad)->checkgetrangefunc)
#define GST_PAD_GETRANGEFUNC(pad)	(GST_PAD_CAST(pad)->getrangefunc)
#define GST_PAD_EVENTFUNC(pad)		(GST_PAD_CAST(pad)->eventfunc)
#define GST_PAD_QUERYTYPEFUNC(pad)	(GST_PAD_CAST(pad)->querytypefunc)
#define GST_PAD_QUERYFUNC(pad)		(GST_PAD_CAST(pad)->queryfunc)
#define GST_PAD_INTLINKFUNC(pad)	(GST_PAD_CAST(pad)->intlinkfunc)

#define GST_PAD_PEER(pad)		(GST_PAD_CAST(pad)->peer)
#define GST_PAD_LINKFUNC(pad)		(GST_PAD_CAST(pad)->linkfunc)
#define GST_PAD_UNLINKFUNC(pad)		(GST_PAD_CAST(pad)->unlinkfunc)

#define GST_PAD_CAPS(pad)		(GST_PAD_CAST(pad)->caps)
#define GST_PAD_GETCAPSFUNC(pad)	(GST_PAD_CAST(pad)->getcapsfunc)
#define GST_PAD_SETCAPSFUNC(pad)	(GST_PAD_CAST(pad)->setcapsfunc)
#define GST_PAD_ACCEPTCAPSFUNC(pad)	(GST_PAD_CAST(pad)->acceptcapsfunc)
#define GST_PAD_FIXATECAPSFUNC(pad)	(GST_PAD_CAST(pad)->fixatecapsfunc)

#define GST_PAD_BUFFERALLOCFUNC(pad)	(GST_PAD_CAST(pad)->bufferallocfunc)

#define GST_PAD_DO_BUFFER_SIGNALS(pad) 	(GST_PAD_CAST(pad)->do_buffer_signals)
#define GST_PAD_DO_EVENT_SIGNALS(pad) 	(GST_PAD_CAST(pad)->do_event_signals)

#define GST_PAD_IS_LINKED(pad)		(GST_PAD_PEER(pad) != NULL)
#define GST_PAD_IS_BLOCKED(pad)		(GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_BLOCKED))
#define GST_PAD_IS_FLUSHING(pad)	(GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_FLUSHING))
#define GST_PAD_IS_IN_GETCAPS(pad)	(GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_IN_GETCAPS))
#define GST_PAD_IS_IN_SETCAPS(pad)	(GST_OBJECT_FLAG_IS_SET (pad, GST_PAD_IN_SETCAPS))
#define GST_PAD_IS_USABLE(pad)		(GST_PAD_IS_LINKED (pad) && \
		                         !GST_PAD_IS_FLUSHING(pad) && !GST_PAD_IS_FLUSHING(GST_PAD_PEER (pad)))
#define GST_PAD_IS_SRC(pad)		(GST_PAD_DIRECTION(pad) == GST_PAD_SRC)
#define GST_PAD_IS_SINK(pad)		(GST_PAD_DIRECTION(pad) == GST_PAD_SINK)

#define GST_PAD_SET_FLUSHING(pad)	(GST_OBJECT_FLAG_SET (pad, GST_PAD_FLUSHING))
#define GST_PAD_UNSET_FLUSHING(pad)	(GST_OBJECT_FLAG_UNSET (pad, GST_PAD_FLUSHING))

#define GST_STREAM_GET_LOCK(pad)        (GST_PAD_CAST(pad)->stream_rec_lock)
#define GST_STREAM_LOCK(pad)            (g_static_rec_mutex_lock(GST_STREAM_GET_LOCK(pad)))
#define GST_STREAM_TRYLOCK(pad)         (g_static_rec_mutex_trylock(GST_STREAM_GET_LOCK(pad)))
#define GST_STREAM_UNLOCK(pad)          (g_static_rec_mutex_unlock(GST_STREAM_GET_LOCK(pad)))
#define GST_STREAM_UNLOCK_FULL(pad)     (g_static_rec_mutex_unlock_full(GST_STREAM_GET_LOCK(pad)))
#define GST_STREAM_LOCK_FULL(pad,t)     (g_static_rec_mutex_lock_full(GST_STREAM_GET_LOCK(pad), t))

#define GST_PREROLL_GET_LOCK(pad)       (GST_PAD_CAST(pad)->preroll_lock)
#define GST_PREROLL_LOCK(pad)           (g_mutex_lock(GST_PREROLL_GET_LOCK(pad)))
#define GST_PREROLL_TRYLOCK(pad)        (g_mutex_trylock(GST_PREROLL_GET_LOCK(pad)))
#define GST_PREROLL_UNLOCK(pad)         (g_mutex_unlock(GST_PREROLL_GET_LOCK(pad)))
#define GST_PREROLL_GET_COND(pad)       (GST_PAD_CAST(pad)->preroll_cond)
#define GST_PREROLL_WAIT(pad)           g_cond_wait (GST_PREROLL_GET_COND (pad), GST_PREROLL_GET_LOCK (pad))
#define GST_PREROLL_TIMED_WAIT(pad, timeval) g_cond_timed_wait (GST_PREROLL_GET_COND (pad), GST_PREROLL_GET_LOCK (pad),\
		                             timeval)
#define GST_PREROLL_SIGNAL(pad)         g_cond_signal (GST_PREROLL_GET_COND (pad));
#define GST_PREROLL_BROADCAST(pad)      g_cond_broadcast (GST_PREROLL_GET_COND (pad));

#define GST_PAD_BLOCK_GET_COND(pad)     (GST_PAD_CAST(pad)->block_cond)
#define GST_PAD_BLOCK_WAIT(pad)         (g_cond_wait(GST_PAD_BLOCK_GET_COND (pad), GST_GET_LOCK (pad)))
#define GST_PAD_BLOCK_SIGNAL(pad)       (g_cond_signal(GST_PAD_BLOCK_GET_COND (pad)))

/* FIXME: this awful circular dependency need to be resolved properly (see padtemplate.h) */
#include <gst/gstpadtemplate.h>

GType			gst_pad_get_type			(void);

/* creating pads */
GstPad*			gst_pad_new				(const gchar *name, GstPadDirection direction);
GstPad*			gst_pad_new_from_template		(GstPadTemplate *templ, const gchar *name);

/**
 * gst_pad_get_name:
 * @pad: the pad to get the name from
 *
 * Returns a copy of the name of the pad.
 *
 * Returns: the name of the pad. g_free() after usage.
 *
 * MT safe.
 */
#define gst_pad_get_name(pad) gst_object_get_name (GST_OBJECT_CAST (pad))
/**
 * gst_pad_get_parent:
 * @pad: the pad to get the parent of
 *
 * Returns the parent of @pad. This function increases the refcount
 * of the parent object so you should gst_object_unref() it after usage.
 *
 * Returns: parent of the object, this can be NULL if the pad has no
 *   parent. unref after usage.
 *
 * MT safe.
 */
#define gst_pad_get_parent(pad) gst_object_get_parent (GST_OBJECT_CAST (pad))

GstPadDirection		gst_pad_get_direction			(GstPad *pad);

gboolean		gst_pad_set_active			(GstPad *pad, gboolean active);
gboolean		gst_pad_is_active			(GstPad *pad);
gboolean		gst_pad_activate_pull			(GstPad *pad, gboolean active);
gboolean		gst_pad_activate_push			(GstPad *pad, gboolean active);

gboolean		gst_pad_set_blocked			(GstPad *pad, gboolean blocked);
gboolean		gst_pad_set_blocked_async		(GstPad *pad, gboolean blocked,
								 GstPadBlockCallback callback, gpointer user_data);
gboolean		gst_pad_is_blocked			(GstPad *pad);

void			gst_pad_set_element_private		(GstPad *pad, gpointer priv);
gpointer		gst_pad_get_element_private		(GstPad *pad);

GstPadTemplate*		gst_pad_get_pad_template		(GstPad *pad);

void			gst_pad_set_bufferalloc_function	(GstPad *pad, GstPadBufferAllocFunction bufalloc);
GstFlowReturn		gst_pad_alloc_buffer			(GstPad *pad, guint64 offset, gint size,
								 GstCaps *caps, GstBuffer **buf);

/* data passing setup functions */
void			gst_pad_set_activate_function		(GstPad *pad, GstPadActivateFunction activate);
void			gst_pad_set_activatepull_function	(GstPad *pad, GstPadActivateModeFunction activatepull);
void			gst_pad_set_activatepush_function	(GstPad *pad, GstPadActivateModeFunction activatepush);
void			gst_pad_set_chain_function		(GstPad *pad, GstPadChainFunction chain);
void			gst_pad_set_getrange_function		(GstPad *pad, GstPadGetRangeFunction get);
void			gst_pad_set_checkgetrange_function	(GstPad *pad, GstPadCheckGetRangeFunction check);
void			gst_pad_set_event_function		(GstPad *pad, GstPadEventFunction event);

/* pad links */
void			gst_pad_set_link_function		(GstPad *pad, GstPadLinkFunction link);
void			gst_pad_set_unlink_function		(GstPad *pad, GstPadUnlinkFunction unlink);

GstPadLinkReturn        gst_pad_link				(GstPad *srcpad, GstPad *sinkpad);
gboolean		gst_pad_unlink				(GstPad *srcpad, GstPad *sinkpad);
gboolean		gst_pad_is_linked			(GstPad *pad);

GstPad*			gst_pad_get_peer			(GstPad *pad);

/* capsnego functions */
void			gst_pad_set_getcaps_function		(GstPad *pad, GstPadGetCapsFunction getcaps);
void			gst_pad_set_acceptcaps_function		(GstPad *pad, GstPadAcceptCapsFunction acceptcaps);
void			gst_pad_set_fixatecaps_function		(GstPad *pad, GstPadFixateCapsFunction fixatecaps);
void			gst_pad_set_setcaps_function		(GstPad *pad, GstPadSetCapsFunction setcaps);

G_CONST_RETURN GstCaps*	gst_pad_get_pad_template_caps		(GstPad *pad);

/* capsnego function for connected/unconnected pads */
GstCaps *		gst_pad_get_caps			(GstPad * pad);
void			gst_pad_fixate_caps			(GstPad * pad, GstCaps *caps);
gboolean		gst_pad_accept_caps			(GstPad * pad, GstCaps *caps);
gboolean		gst_pad_set_caps			(GstPad * pad, GstCaps *caps);

GstCaps *		gst_pad_peer_get_caps			(GstPad * pad);
gboolean		gst_pad_peer_accept_caps		(GstPad * pad, GstCaps *caps);

/* capsnego for connected pads */
GstCaps *		gst_pad_get_allowed_caps		(GstPad * srcpad);
GstCaps *		gst_pad_get_negotiated_caps		(GstPad * pad);

/* data passing functions to peer */
GstFlowReturn		gst_pad_push				(GstPad *pad, GstBuffer *buffer);
gboolean		gst_pad_check_pull_range		(GstPad *pad);
GstFlowReturn		gst_pad_pull_range			(GstPad *pad, guint64 offset, guint size,
								 GstBuffer **buffer);
gboolean		gst_pad_push_event			(GstPad *pad, GstEvent *event);
gboolean		gst_pad_event_default			(GstPad *pad, GstEvent *event);

/* data passing functions on pad */
GstFlowReturn		gst_pad_chain				(GstPad *pad, GstBuffer *buffer);
GstFlowReturn		gst_pad_get_range			(GstPad *pad, guint64 offset, guint size,
								 GstBuffer **buffer);
gboolean		gst_pad_send_event			(GstPad *pad, GstEvent *event);

/* pad tasks */
gboolean		gst_pad_start_task			(GstPad *pad, GstTaskFunction func,
								 gpointer data);
gboolean		gst_pad_pause_task			(GstPad *pad);
gboolean		gst_pad_stop_task			(GstPad *pad);

/* internal links */
void			gst_pad_set_internal_link_function	(GstPad *pad, GstPadIntLinkFunction intlink);
GList*			gst_pad_get_internal_links		(GstPad *pad);
GList*			gst_pad_get_internal_links_default	(GstPad *pad);

/* generic query function */
void			gst_pad_set_query_type_function		(GstPad *pad, GstPadQueryTypeFunction type_func);
G_CONST_RETURN GstQueryType*
			gst_pad_get_query_types			(GstPad *pad);
G_CONST_RETURN GstQueryType*
			gst_pad_get_query_types_default		(GstPad *pad);

gboolean		gst_pad_query				(GstPad *pad, GstQuery *query);
void			gst_pad_set_query_function		(GstPad *pad, GstPadQueryFunction query);
gboolean		gst_pad_query_default			(GstPad *pad, GstQuery *query);

/* misc helper functions */
gboolean		gst_pad_dispatcher			(GstPad *pad, GstPadDispatcherFunction dispatch,
								 gpointer data);

#ifndef GST_DISABLE_LOADSAVE
void			gst_pad_load_and_link			(xmlNodePtr self, GstObject *parent);
#endif

G_END_DECLS

#endif /* __GST_PAD_H__ */