/* 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., 51 Franklin St, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 */

#ifndef __GST_PAD_H__

#define __GST_PAD_H__

#include <gst/gstconfig.h>

typedef struct _GstPad GstPad;

typedef struct _GstPadPrivate GstPadPrivate;

typedef struct _GstPadClass GstPadClass;

typedef struct _GstPadProbeInfo GstPadProbeInfo;

/**

 * 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;

/**

 * GstPadMode:

 * @GST_PAD_MODE_NONE: Pad will not handle dataflow

 * @GST_PAD_MODE_PUSH: Pad handles dataflow in downstream push mode

 * @GST_PAD_MODE_PULL: Pad handles dataflow in upstream pull mode

 *

 * The status of a GstPad. After activating a pad, which usually happens when the

 * parent element goes from READY to PAUSED, the GstPadMode defines if the

 * pad operates in push or pull mode.

 */

typedef enum {

  GST_PAD_MODE_NONE,

  GST_PAD_MODE_PUSH,

  GST_PAD_MODE_PULL

} GstPadMode;

#include <glib.h>

GST_API

const gchar   * gst_pad_mode_get_name (GstPadMode mode);

#include <gst/gstobject.h>

#include <gst/gstbuffer.h>

#include <gst/gstbufferlist.h>

#include <gst/gstcaps.h>

#include <gst/gstpadtemplate.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_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))

/**

 * 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

 *

 * Result values from gst_pad_link and friends.

 */

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_OK:		 Data passing was ok.

 * @GST_FLOW_NOT_LINKED:	 Pad is not linked.

 * @GST_FLOW_FLUSHING:	         Pad is flushing.

 * @GST_FLOW_EOS:                Pad is EOS.

 * @GST_FLOW_NOT_NEGOTIATED:	 Pad is not negotiated.

 * @GST_FLOW_ERROR:		 Some (fatal) error occurred. Element generating

 *                               this error should post an error message with more

 *                               details.

 * @GST_FLOW_NOT_SUPPORTED:	 This operation is not supported.

 * @GST_FLOW_CUSTOM_SUCCESS:	 Elements can use values starting from

 *                               this (and higher) to define custom success

 *                               codes.

 * @GST_FLOW_CUSTOM_SUCCESS_1:	 Pre-defined custom success code (define your

 *                               custom success code to this to avoid compiler

 *                               warnings).

 * @GST_FLOW_CUSTOM_SUCCESS_2:	 Pre-defined custom success code.

 * @GST_FLOW_CUSTOM_ERROR:	 Elements can use values starting from

 *                               this (and lower) to define custom error codes.

 * @GST_FLOW_CUSTOM_ERROR_1:	 Pre-defined custom error code (define your

 *                               custom error code to this to avoid compiler

 *                               warnings).

 * @GST_FLOW_CUSTOM_ERROR_2:	 Pre-defined custom error code.

 *

 * The result of passing data to a pad.

 *

 * Note that the custom return values should not be exposed outside of the

 * element scope.

 */

typedef enum {

  /* custom success starts here */

  GST_FLOW_CUSTOM_SUCCESS_2 = 102,

  GST_FLOW_CUSTOM_SUCCESS_1 = 101,

  GST_FLOW_CUSTOM_SUCCESS = 100,

  /* core predefined */

  GST_FLOW_OK		  =  0,

  /* expected failures */

  GST_FLOW_NOT_LINKED     = -1,

  GST_FLOW_FLUSHING       = -2,

  /* error cases */

  GST_FLOW_EOS            = -3,

  GST_FLOW_NOT_NEGOTIATED = -4,

  GST_FLOW_ERROR	  = -5,

  GST_FLOW_NOT_SUPPORTED  = -6,

  /* custom error starts here */

  GST_FLOW_CUSTOM_ERROR   = -100,

  GST_FLOW_CUSTOM_ERROR_1 = -101,

  GST_FLOW_CUSTOM_ERROR_2 = -102

} GstFlowReturn;

GST_API

const gchar *         gst_flow_get_name (GstFlowReturn ret);

GST_API

GQuark                gst_flow_to_quark (GstFlowReturn ret);

GST_API

const gchar *         gst_pad_link_get_name (GstPadLinkReturn ret);

/**

 * GstPadLinkCheck:

 * @GST_PAD_LINK_CHECK_NOTHING: Don't check hierarchy or caps compatibility.

 * @GST_PAD_LINK_CHECK_HIERARCHY: Check the pads have same parents/grandparents.

 *   Could be omitted if it is already known that the two elements that own the

 *   pads are in the same bin.

 * @GST_PAD_LINK_CHECK_TEMPLATE_CAPS: Check if the pads are compatible by using

 *   their template caps. This is much faster than @GST_PAD_LINK_CHECK_CAPS, but

 *   would be unsafe e.g. if one pad has %GST_CAPS_ANY.

 * @GST_PAD_LINK_CHECK_CAPS: Check if the pads are compatible by comparing the

 *   caps returned by gst_pad_query_caps().

 * @GST_PAD_LINK_CHECK_NO_RECONFIGURE: Disables pushing a reconfigure event when pads are

 *   linked.

 * @GST_PAD_LINK_CHECK_DEFAULT: The default checks done when linking

 *   pads (i.e. the ones used by gst_pad_link()).

 *

 * The amount of checking to be done when linking pads. @GST_PAD_LINK_CHECK_CAPS

 * and @GST_PAD_LINK_CHECK_TEMPLATE_CAPS are mutually exclusive. If both are

 * specified, expensive but safe @GST_PAD_LINK_CHECK_CAPS are performed.

 *

 * > Only disable some of the checks if you are 100% certain you know the link

 * > will not fail because of hierarchy/caps compatibility failures. If uncertain,

 * > use the default checks (%GST_PAD_LINK_CHECK_DEFAULT) or the regular methods

 * > for linking the pads.

 */

typedef enum {

  GST_PAD_LINK_CHECK_NOTHING       = 0,

  GST_PAD_LINK_CHECK_HIERARCHY     = 1 << 0,

  GST_PAD_LINK_CHECK_TEMPLATE_CAPS = 1 << 1,

  GST_PAD_LINK_CHECK_CAPS          = 1 << 2,

  /* Not really checks, more like flags

   * Added here to avoid creating a new gst_pad_link_variant */

  GST_PAD_LINK_CHECK_NO_RECONFIGURE = 1 << 3,

  GST_PAD_LINK_CHECK_DEFAULT       = GST_PAD_LINK_CHECK_HIERARCHY | GST_PAD_LINK_CHECK_CAPS

} GstPadLinkCheck;

/* pad states */

/**

 * GstPadActivateFunction:

 * @pad: a #GstPad

 * @parent: the parent of @pad

 *

 * This function is called when the pad is activated during the element

 * READY to PAUSED state change. By default this function will call the

 * activate function that puts the pad in push mode but elements can

 * override this function to activate the pad in pull mode if they wish.

 *

 * Returns: %TRUE if the pad could be activated.

 */

typedef gboolean		(*GstPadActivateFunction)	(GstPad *pad, GstObject *parent);

/**

 * GstPadActivateModeFunction:

 * @pad: a #GstPad

 * @parent: the parent of @pad

 * @mode: the requested activation mode of @pad

 * @active: activate or deactivate the pad.

 *

 * The prototype of the push and pull activate functions.

 *

 * Returns: %TRUE if the pad could be activated or deactivated.

 */

typedef gboolean		(*GstPadActivateModeFunction)	(GstPad *pad, GstObject *parent,

                                                                 GstPadMode mode, gboolean active);

/* data passing */

/**

 * GstPadChainFunction:

 * @pad: the sink #GstPad that performed the chain.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @buffer: (transfer full): the #GstBuffer that is chained, not %NULL.

 *

 * A function that will be called on sinkpads when chaining buffers.

 * The function typically processes the data contained in the buffer and

 * either consumes the data or passes it on to the internally linked pad(s).

 *

 * The implementer of this function receives a refcount to @buffer and should

 * gst_buffer_unref() when the buffer is no longer needed.

 *

 * When a chain function detects an error in the data stream, it must post an

 * error on the bus and return an appropriate #GstFlowReturn value.

 *

 * Returns: #GST_FLOW_OK for success

 */

typedef GstFlowReturn		(*GstPadChainFunction)		(GstPad *pad, GstObject *parent,

                                                                 GstBuffer *buffer);

/**

 * GstPadChainListFunction:

 * @pad: the sink #GstPad that performed the chain.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @list: (transfer full): the #GstBufferList that is chained, not %NULL.

 *

 * A function that will be called on sinkpads when chaining buffer lists.

 * The function typically processes the data contained in the buffer list and

 * either consumes the data or passes it on to the internally linked pad(s).

 *

 * The implementer of this function receives a refcount to @list and

 * should gst_buffer_list_unref() when the list is no longer needed.

 *

 * When a chainlist function detects an error in the data stream, it must

 * post an error on the bus and return an appropriate #GstFlowReturn value.

 *

 * Returns: #GST_FLOW_OK for success

 */

typedef GstFlowReturn		(*GstPadChainListFunction)	(GstPad *pad, GstObject *parent,

                                                                 GstBufferList *list);

/**

 * GstPadGetRangeFunction:

 * @pad: the src #GstPad to perform the getrange on.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @offset: the offset of the range

 * @length: the length of the range

 * @buffer: a memory location to hold the result buffer, cannot be %NULL.

 *

 * This function will be called on source pads when a peer element

 * request a buffer at the specified @offset and @length. If this function

 * returns #GST_FLOW_OK, the result buffer will be stored in @buffer. The

 * contents of @buffer is invalid for any other return value.

 *

 * This function is installed on a source pad with

 * gst_pad_set_getrange_function() and can only be called on source pads after

 * they are successfully activated with gst_pad_activate_mode() with the

 * #GST_PAD_MODE_PULL.

 *

 * @offset and @length are always given in byte units. @offset must normally be a value

 * between 0 and the length in bytes of the data available on @pad. The

 * length (duration in bytes) can be retrieved with a #GST_QUERY_DURATION or with a

 * #GST_QUERY_SEEKING.

 *

 * Any @offset larger or equal than the length will make the function return

 * #GST_FLOW_EOS, which corresponds to EOS. In this case @buffer does not

 * contain a valid buffer.

 *

 * The buffer size of @buffer will only be smaller than @length when @offset is

 * near the end of the stream. In all other cases, the size of @buffer must be

 * exactly the requested size.

 *

 * It is allowed to call this function with a 0 @length and valid @offset, in

 * which case @buffer will contain a 0-sized buffer and the function returns

 * #GST_FLOW_OK.

 *

 * When this function is called with a -1 @offset, the sequentially next buffer

 * of length @length in the stream is returned.

 *

 * When this function is called with a -1 @length, a buffer with a default

 * optimal length is returned in @buffer. The length might depend on the value

 * of @offset.

 *

 * Returns: #GST_FLOW_OK for success and a valid buffer in @buffer. Any other

 * return value leaves @buffer undefined.

 */

typedef GstFlowReturn		(*GstPadGetRangeFunction)	(GstPad *pad, GstObject *parent,

                                                                 guint64 offset, guint length,

                                                                 GstBuffer **buffer);

/**

 * GstPadEventFunction:

 * @pad: the #GstPad to handle the event.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @event: (transfer full): 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, GstObject *parent,

                                                                 GstEvent *event);

/**

 * GstPadEventFullFunction:

 * @pad: the #GstPad to handle the event.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @event: (transfer full): the #GstEvent to handle.

 *

 * Function signature to handle an event for the pad.

 *

 * This variant is for specific elements that will take into account the

 * last downstream flow return (from a pad push), in which case they can

 * return it.

 *

 * Returns: %GST_FLOW_OK if the event was handled properly, or any other

 * #GstFlowReturn dependent on downstream state.

 *

 * Since: 1.8

 */

typedef GstFlowReturn		(*GstPadEventFullFunction)	(GstPad *pad, GstObject *parent,

                                                                 GstEvent *event);

/* internal links */

/**

 * GstPadIterIntLinkFunction:

 * @pad: The #GstPad to query.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 *

 * The signature of the internal pad link iterator function.

 *

 * Returns: a new #GstIterator that will iterate over all pads that are

 * linked to the given pad on the inside of the parent element.

 *

 * the caller must call gst_iterator_free() after usage.

 */

typedef GstIterator*           (*GstPadIterIntLinkFunction)    (GstPad *pad, GstObject *parent);

/* generic query function */

/**

 * GstPadQueryFunction:

 * @pad: the #GstPad to query.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @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, GstObject *parent,

                                                                 GstQuery *query);

/* linking */

/**

 * GstPadLinkFunction:

 * @pad: the #GstPad that is linked.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 * @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, GstObject *parent, GstPad *peer);

/**

 * GstPadUnlinkFunction:

 * @pad: the #GstPad that is linked.

 * @parent: (allow-none): the parent of @pad. If the #GST_PAD_FLAG_NEED_PARENT

 *          flag is set, @parent is guaranteed to be not-%NULL and remain valid

 *          during the execution of this function.

 *

 * Function signature to handle a unlinking the pad prom its peer.

 */

typedef void			(*GstPadUnlinkFunction)		(GstPad *pad, GstObject *parent);

/* misc */

/**

 * GstPadForwardFunction:

 * @pad: the #GstPad that is forwarded.

 * @user_data: the gpointer to optional user data.

 *

 * A forward function is called for all internally linked pads, see

 * gst_pad_forward().

 *

 * Returns: %TRUE if the dispatching procedure has to be stopped.

 */

typedef gboolean		(*GstPadForwardFunction)	(GstPad *pad, gpointer user_data);

/**

 * GstPadProbeType:

 * @GST_PAD_PROBE_TYPE_INVALID: invalid probe type

 * @GST_PAD_PROBE_TYPE_IDLE: probe idle pads and block while the callback is called

 * @GST_PAD_PROBE_TYPE_BLOCK: probe and block pads

 * @GST_PAD_PROBE_TYPE_BUFFER: probe buffers

 * @GST_PAD_PROBE_TYPE_BUFFER_LIST: probe buffer lists

 * @GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM: probe downstream events

 * @GST_PAD_PROBE_TYPE_EVENT_UPSTREAM: probe upstream events

 * @GST_PAD_PROBE_TYPE_EVENT_FLUSH: probe flush events. This probe has to be

 *     explicitly enabled and is not included in the

 *     @@GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM or

 *     @@GST_PAD_PROBE_TYPE_EVENT_UPSTREAM probe types.

 * @GST_PAD_PROBE_TYPE_QUERY_DOWNSTREAM: probe downstream queries

 * @GST_PAD_PROBE_TYPE_QUERY_UPSTREAM: probe upstream queries

 * @GST_PAD_PROBE_TYPE_PUSH: probe push

 * @GST_PAD_PROBE_TYPE_PULL: probe pull

 * @GST_PAD_PROBE_TYPE_BLOCKING: probe and block at the next opportunity, at data flow or when idle

 * @GST_PAD_PROBE_TYPE_DATA_DOWNSTREAM: probe downstream data (buffers, buffer lists, and events)

 * @GST_PAD_PROBE_TYPE_DATA_UPSTREAM: probe upstream data (events)

 * @GST_PAD_PROBE_TYPE_DATA_BOTH: probe upstream and downstream data (buffers, buffer lists, and events)

 * @GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM: probe and block downstream data (buffers, buffer lists, and events)

 * @GST_PAD_PROBE_TYPE_BLOCK_UPSTREAM: probe and block upstream data (events)

 * @GST_PAD_PROBE_TYPE_EVENT_BOTH: probe upstream and downstream events

 * @GST_PAD_PROBE_TYPE_QUERY_BOTH: probe upstream and downstream queries

 * @GST_PAD_PROBE_TYPE_ALL_BOTH: probe upstream events and queries and downstream buffers, buffer lists, events and queries

 * @GST_PAD_PROBE_TYPE_SCHEDULING: probe push and pull

 *

 * The different probing types that can occur. When either one of

 * @GST_PAD_PROBE_TYPE_IDLE or @GST_PAD_PROBE_TYPE_BLOCK is used, the probe will be a

 * blocking probe.

 */

typedef enum

{

  GST_PAD_PROBE_TYPE_INVALID          = 0,

  /* flags to control blocking */

  GST_PAD_PROBE_TYPE_IDLE             = (1 << 0),

  GST_PAD_PROBE_TYPE_BLOCK            = (1 << 1),

  /* flags to select datatypes */

  GST_PAD_PROBE_TYPE_BUFFER           = (1 << 4),

  GST_PAD_PROBE_TYPE_BUFFER_LIST      = (1 << 5),

  GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM = (1 << 6),

  GST_PAD_PROBE_TYPE_EVENT_UPSTREAM   = (1 << 7),

  GST_PAD_PROBE_TYPE_EVENT_FLUSH      = (1 << 8),

  GST_PAD_PROBE_TYPE_QUERY_DOWNSTREAM = (1 << 9),

  GST_PAD_PROBE_TYPE_QUERY_UPSTREAM   = (1 << 10),

  /* flags to select scheduling mode */

  GST_PAD_PROBE_TYPE_PUSH             = (1 << 12),

  GST_PAD_PROBE_TYPE_PULL             = (1 << 13),

  /* flag combinations */

  GST_PAD_PROBE_TYPE_BLOCKING         = GST_PAD_PROBE_TYPE_IDLE | GST_PAD_PROBE_TYPE_BLOCK,

  GST_PAD_PROBE_TYPE_DATA_DOWNSTREAM  = GST_PAD_PROBE_TYPE_BUFFER | GST_PAD_PROBE_TYPE_BUFFER_LIST | GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM,

  GST_PAD_PROBE_TYPE_DATA_UPSTREAM    = GST_PAD_PROBE_TYPE_EVENT_UPSTREAM,

  GST_PAD_PROBE_TYPE_DATA_BOTH        = GST_PAD_PROBE_TYPE_DATA_DOWNSTREAM | GST_PAD_PROBE_TYPE_DATA_UPSTREAM,

  GST_PAD_PROBE_TYPE_BLOCK_DOWNSTREAM = GST_PAD_PROBE_TYPE_BLOCK | GST_PAD_PROBE_TYPE_DATA_DOWNSTREAM,

  GST_PAD_PROBE_TYPE_BLOCK_UPSTREAM   = GST_PAD_PROBE_TYPE_BLOCK | GST_PAD_PROBE_TYPE_DATA_UPSTREAM,

  GST_PAD_PROBE_TYPE_EVENT_BOTH       = GST_PAD_PROBE_TYPE_EVENT_DOWNSTREAM | GST_PAD_PROBE_TYPE_EVENT_UPSTREAM,

  GST_PAD_PROBE_TYPE_QUERY_BOTH       = GST_PAD_PROBE_TYPE_QUERY_DOWNSTREAM | GST_PAD_PROBE_TYPE_QUERY_UPSTREAM,

  GST_PAD_PROBE_TYPE_ALL_BOTH         = GST_PAD_PROBE_TYPE_DATA_BOTH | GST_PAD_PROBE_TYPE_QUERY_BOTH,

  GST_PAD_PROBE_TYPE_SCHEDULING       = GST_PAD_PROBE_TYPE_PUSH | GST_PAD_PROBE_TYPE_PULL

} GstPadProbeType;

/**

 * GstPadProbeReturn:

 * @GST_PAD_PROBE_OK: normal probe return value. This leaves the probe in

 *        place, and defers decisions about dropping or passing data to other

 *        probes, if any. If there are no other probes, the default behaviour

 *        for the probe type applies ('block' for blocking probes,

 *        and 'pass' for non-blocking probes).

 * @GST_PAD_PROBE_DROP: drop data in data probes. For push mode this means that

 *        the data item is not sent downstream. For pull mode, it means that

 *        the data item is not passed upstream. In both cases, no other probes

 *        are called for this item and %GST_FLOW_OK or %TRUE is returned to the

 *        caller.

 * @GST_PAD_PROBE_REMOVE: remove this probe.

 * @GST_PAD_PROBE_PASS: pass the data item in the block probe and block on the

 *        next item.

 * @GST_PAD_PROBE_HANDLED: Data has been handled in the probe and will not be

 *        forwarded further. For events and buffers this is the same behaviour as

 *        %GST_PAD_PROBE_DROP (except that in this case you need to unref the buffer

 *        or event yourself). For queries it will also return %TRUE to the caller.

 *        The probe can also modify the #GstFlowReturn value by using the

 *        #GST_PAD_PROBE_INFO_FLOW_RETURN() accessor.

 *        Note that the resulting query must contain valid entries.

 *        Since: 1.6

 *

 * Different return values for the #GstPadProbeCallback.

 */

typedef enum

{

  GST_PAD_PROBE_DROP,

  GST_PAD_PROBE_OK,

  GST_PAD_PROBE_REMOVE,

  GST_PAD_PROBE_PASS,

  GST_PAD_PROBE_HANDLED

} GstPadProbeReturn;

/**

 * GstPadProbeInfo:

 * @type: the current probe type

 * @id: the id of the probe

 * @data: (allow-none): type specific data, check the @type field to know the

 *    datatype.  This field can be %NULL.

 * @offset: offset of pull probe, this field is valid when @type contains

 *    #GST_PAD_PROBE_TYPE_PULL

 * @size: size of pull probe, this field is valid when @type contains

 *    #GST_PAD_PROBE_TYPE_PULL

 *

 * Info passed in the #GstPadProbeCallback.

 */

struct _GstPadProbeInfo

{

  GstPadProbeType type;

  gulong id;

  gpointer data;

  guint64 offset;

  guint size;

  /*< private >*/

  union {

    gpointer _gst_reserved[GST_PADDING];

    struct {

      GstFlowReturn flow_ret;

    } abi;

  } ABI;

};

#define GST_PAD_PROBE_INFO_TYPE(d)         ((d)->type)

#define GST_PAD_PROBE_INFO_ID(d)           ((d)->id)

#define GST_PAD_PROBE_INFO_DATA(d)         ((d)->data)

#define GST_PAD_PROBE_INFO_FLOW_RETURN(d)  ((d)->ABI.abi.flow_ret)

#define GST_PAD_PROBE_INFO_BUFFER(d)       GST_BUFFER_CAST(GST_PAD_PROBE_INFO_DATA(d))

#define GST_PAD_PROBE_INFO_BUFFER_LIST(d)  GST_BUFFER_LIST_CAST(GST_PAD_PROBE_INFO_DATA(d))

#define GST_PAD_PROBE_INFO_EVENT(d)        GST_EVENT_CAST(GST_PAD_PROBE_INFO_DATA(d))

#define GST_PAD_PROBE_INFO_QUERY(d)        GST_QUERY_CAST(GST_PAD_PROBE_INFO_DATA(d))

#define GST_PAD_PROBE_INFO_OFFSET(d)       ((d)->offset)

#define GST_PAD_PROBE_INFO_SIZE(d)         ((d)->size)

GST_API

GstEvent*      gst_pad_probe_info_get_event       (GstPadProbeInfo * info);

GST_API

GstQuery*      gst_pad_probe_info_get_query       (GstPadProbeInfo * info);

GST_API

GstBuffer*     gst_pad_probe_info_get_buffer      (GstPadProbeInfo * info);

GST_API

GstBufferList* gst_pad_probe_info_get_buffer_list (GstPadProbeInfo * info);

/**

 * GstPadProbeCallback:

 * @pad: the #GstPad that is blocked

 * @info: #GstPadProbeInfo

 * @user_data: the gpointer to optional user data.

 *

 * Callback used by gst_pad_add_probe(). Gets called to notify about the current

 * blocking type.

 *

 * The callback is allowed to modify the data pointer in @info.

 *

 * Returns: a #GstPadProbeReturn

 */

typedef GstPadProbeReturn   (*GstPadProbeCallback)   (GstPad *pad, GstPadProbeInfo *info,

                                                      gpointer user_data);

/**

 * GstPadStickyEventsForeachFunction:

 * @pad: the #GstPad.

 * @event: (allow-none): a sticky #GstEvent.

 * @user_data: the #gpointer to optional user data.

 *

 * Callback used by gst_pad_sticky_events_foreach().

 *

 * When this function returns %TRUE, the next event will be

 * returned. When %FALSE is returned, gst_pad_sticky_events_foreach() will return.

 *

 * When @event is set to %NULL, the item will be removed from the list of sticky events.

 * @event can be replaced by assigning a new reference to it.

 * This function is responsible for unreffing the old event when

 * removing or modifying.

 *

 * Returns: %TRUE if the iteration should continue

 */

typedef gboolean  (*GstPadStickyEventsForeachFunction) (GstPad *pad, GstEvent **event,

                                                        gpointer user_data);

/**

 * GstPadFlags:

 * @GST_PAD_FLAG_BLOCKED: is dataflow on a pad blocked

 * @GST_PAD_FLAG_FLUSHING: is pad flushing

 * @GST_PAD_FLAG_EOS: is pad in EOS state

 * @GST_PAD_FLAG_BLOCKING: is pad currently blocking on a buffer or event

 * @GST_PAD_FLAG_NEED_PARENT: ensure that there is a parent object before calling

 *                       into the pad callbacks.

 * @GST_PAD_FLAG_NEED_RECONFIGURE: the pad should be reconfigured/renegotiated.

 *                            The flag has to be unset manually after

 *                            reconfiguration happened.

 * @GST_PAD_FLAG_PENDING_EVENTS: the pad has pending events

 * @GST_PAD_FLAG_FIXED_CAPS: the pad is using fixed caps. This means that

 *     once the caps are set on the pad, the default caps query function

 *     will only return those caps.

 * @GST_PAD_FLAG_PROXY_CAPS: the default event and query handler will forward

 *                      all events and queries to the internally linked pads

 *                      instead of discarding them.

 * @GST_PAD_FLAG_PROXY_ALLOCATION: the default query handler will forward

 *                      allocation queries to the internally linked pads

 *                      instead of discarding them.

 * @GST_PAD_FLAG_PROXY_SCHEDULING: the default query handler will forward

 *                      scheduling queries to the internally linked pads

 *                      instead of discarding them.

 * @GST_PAD_FLAG_ACCEPT_INTERSECT: the default accept-caps handler will check

 *                      it the caps intersect the query-caps result instead

 *                      of checking for a subset. This is interesting for

 *                      parsers that can accept incompletely specified caps.

 * @GST_PAD_FLAG_ACCEPT_TEMPLATE: the default accept-caps handler will use

 *                      the template pad caps instead of query caps to

 *                      compare with the accept caps. Use this in combination

 *                      with %GST_PAD_FLAG_ACCEPT_INTERSECT. (Since 1.6)

 * @GST_PAD_FLAG_LAST: offset to define more flags

 *

 * Pad state flags

 */

typedef enum {

  GST_PAD_FLAG_BLOCKED          = (GST_OBJECT_FLAG_LAST << 0),

  GST_PAD_FLAG_FLUSHING         = (GST_OBJECT_FLAG_LAST << 1),

  GST_PAD_FLAG_EOS              = (GST_OBJECT_FLAG_LAST << 2),

  GST_PAD_FLAG_BLOCKING         = (GST_OBJECT_FLAG_LAST << 3),

  GST_PAD_FLAG_NEED_PARENT      = (GST_OBJECT_FLAG_LAST << 4),

  GST_PAD_FLAG_NEED_RECONFIGURE = (GST_OBJECT_FLAG_LAST << 5),

  GST_PAD_FLAG_PENDING_EVENTS   = (GST_OBJECT_FLAG_LAST << 6),

  GST_PAD_FLAG_FIXED_CAPS       = (GST_OBJECT_FLAG_LAST << 7),

  GST_PAD_FLAG_PROXY_CAPS       = (GST_OBJECT_FLAG_LAST << 8),

  GST_PAD_FLAG_PROXY_ALLOCATION = (GST_OBJECT_FLAG_LAST << 9),

  GST_PAD_FLAG_PROXY_SCHEDULING = (GST_OBJECT_FLAG_LAST << 10),

  GST_PAD_FLAG_ACCEPT_INTERSECT = (GST_OBJECT_FLAG_LAST << 11),

  GST_PAD_FLAG_ACCEPT_TEMPLATE  = (GST_OBJECT_FLAG_LAST << 12),

  /* padding */

  GST_PAD_FLAG_LAST        = (GST_OBJECT_FLAG_LAST << 16)

} GstPadFlags;

/**

 * GstPad:

 * @element_private: private data owned by the parent element

 * @padtemplate: padtemplate for this pad

 * @direction: the direction of the pad, cannot change after creating

 *             the pad.

 *

 * The #GstPad structure. Use the functions to update the variables.

 */

struct _GstPad {

  GstObject                      object;

  /*< public >*/

  gpointer                       element_private;

  GstPadTemplate                *padtemplate;

  GstPadDirection                direction;

  /*< private >*/

  /* streaming rec_lock */

  GRecMutex		         stream_rec_lock;

  GstTask			*task;

  /* block cond, mutex is from the object */

  GCond				 block_cond;

  GHookList                      probes;

  GstPadMode		         mode;

  GstPadActivateFunction	 activatefunc;

  gpointer                       activatedata;

  GDestroyNotify                 activatenotify;

  GstPadActivateModeFunction	 activatemodefunc;

  gpointer                       activatemodedata;

  GDestroyNotify                 activatemodenotify;

  /* pad link */

  GstPad			*peer;

  GstPadLinkFunction		 linkfunc;

  gpointer                       linkdata;

  GDestroyNotify                 linknotify;

  GstPadUnlinkFunction		 unlinkfunc;

  gpointer                       unlinkdata;

  GDestroyNotify                 unlinknotify;

  /* data transport functions */

  GstPadChainFunction		 chainfunc;

  gpointer                       chaindata;

  GDestroyNotify                 chainnotify;

  GstPadChainListFunction        chainlistfunc;

  gpointer                       chainlistdata;

  GDestroyNotify                 chainlistnotify;

  GstPadGetRangeFunction	 getrangefunc;

  gpointer                       getrangedata;

  GDestroyNotify                 getrangenotify;

  GstPadEventFunction		 eventfunc;

  gpointer                       eventdata;

  GDestroyNotify                 eventnotify;

  /* pad offset */

  gint64                         offset;

  /* generic query method */

  GstPadQueryFunction		 queryfunc;

  gpointer                       querydata;

  GDestroyNotify                 querynotify;

  /* internal links */

  GstPadIterIntLinkFunction      iterintlinkfunc;

  gpointer                       iterintlinkdata;

  GDestroyNotify                 iterintlinknotify;

  /* counts number of probes attached. */

  gint				 num_probes;

  gint				 num_blocked;

  GstPadPrivate                 *priv;

  union {

    gpointer _gst_reserved[GST_PADDING];

    struct {

      GstFlowReturn last_flowret;

      GstPadEventFullFunction eventfullfunc;

    } abi;

  } ABI;

};

struct _GstPadClass {

  GstObjectClass	parent_class;

  /* signal callbacks */

  void		(*linked)		(GstPad *pad, GstPad *peer);

  void		(*unlinked)		(GstPad *pad, GstPad *peer);

  /*< private >*/

  gpointer _gst_reserved[GST_PADDING];

};

/***** helper macros *****/

/* GstPad */

/**

 * GST_PAD_NAME:

 * @pad: a #GstPad

 *

 * Get name of the given pad.

 * No locking is performed in this function, use gst_pad_get_name() instead.

 */

#define GST_PAD_NAME(pad)		(GST_OBJECT_NAME(pad))

/**

 * GST_PAD_PARENT:

 * @pad: a #GstPad

 *

 * Get the @pad parent.

 * No locking is performed in this function, use gst_pad_get_parent() instead.

 */

#define GST_PAD_PARENT(pad)		(GST_ELEMENT_CAST(GST_OBJECT_PARENT(pad)))

/**

 * GST_PAD_ELEMENT_PRIVATE:

 * @pad: a #GstPad

 *

 * Get the private data of @pad, which is usually some pad- or stream-specific

 * structure created by the element and set on the pad when creating it.

 * No locking is performed in this function.

 */

#define GST_PAD_ELEMENT_PRIVATE(pad)    (GST_PAD_CAST(pad)->element_private)

/**

 * GST_PAD_PAD_TEMPLATE:

 * @pad: a #GstPad

 *

 * Get the @pad #GstPadTemplate. It describes the possible media types

 * a @pad or an element factory can handle.

 */

#define GST_PAD_PAD_TEMPLATE(pad)	(GST_PAD_CAST(pad)->padtemplate)

/**

 * GST_PAD_DIRECTION:

 * @pad: a #GstPad

 *

 * Get the #GstPadDirection of the given @pad. Accessor macro, use

 * gst_pad_get_direction() instead.

 */

#define GST_PAD_DIRECTION(pad)		(GST_PAD_CAST(pad)->direction)

/**

 * GST_PAD_TASK:

 * @pad: a #GstPad

 *

 * Get the #GstTask of @pad. Accessor macro used by GStreamer. Use the

 * gst_pad_start_task(), gst_pad_stop_task() and gst_pad_pause_task()

 * functions instead.

 */

#define GST_PAD_TASK(pad)		(GST_PAD_CAST(pad)->task)

/**

 * GST_PAD_MODE:

 * @pad: a #GstPad

 *

 * Get the #GstPadMode of pad, which will be GST_PAD_MODE_NONE if the pad

 * has not been activated yet, and otherwise either GST_PAD_MODE_PUSH or

 * GST_PAD_MODE_PULL depending on which mode the pad was activated in.

 */

#define GST_PAD_MODE(pad)	        (GST_PAD_CAST(pad)->mode)

/**

 * GST_PAD_ACTIVATEFUNC: