/* 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., 51 Franklin St, Fifth Floor,

 * Boston, MA 02110-1301, USA.

 */

#ifndef __GST_ELEMENT_H__

#define __GST_ELEMENT_H__

#include <glib.h>

G_BEGIN_DECLS

/* 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, it is ready to accept and

 *                          process data. Sink elements however only accept one

 *                          buffer and then block.

 * @GST_STATE_PLAYING     : the element is PLAYING, the #GstClock is running and

 *                          the data is flowing.

 *

 * The possible states an element can be in. States can be changed using

 * gst_element_set_state() and checked using gst_element_get_state().

 */

typedef enum {

  GST_STATE_VOID_PENDING        = 0,

  GST_STATE_NULL                = 1,

  GST_STATE_READY               = 2,

  GST_STATE_PAUSED              = 3,

  GST_STATE_PLAYING             = 4

} GstState;

#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 succeeded but the element

 *                               cannot produce data in %GST_STATE_PAUSED.

 *                               This typically happens with live sources.

 *

 * The possible return values from a state change function such as

 * gst_element_set_state(). Only @GST_STATE_CHANGE_FAILURE is a real failure.

 */

typedef enum {

  GST_STATE_CHANGE_FAILURE             = 0,

  GST_STATE_CHANGE_SUCCESS             = 1,

  GST_STATE_CHANGE_ASYNC               = 2,

  GST_STATE_CHANGE_NO_PREROLL          = 3

} GstStateChangeReturn;

#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/gstiterator.h>

#include <gst/gstmessage.h>

#include <gst/gstquery.h>

#include <gst/gsttaglist.h>

#include <gst/gstcontext.h>

/* 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_TARGET:

 * @elem: a #GstElement to return the target state for.

 *

 * This macro returns the target #GstState of the element.

 */

#define GST_STATE_TARGET(elem)          (GST_ELEMENT_CAST(elem)->target_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)         ((GstState)((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)          ((GstStateChange)(((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)     ((GstState)((trans)>>3))

/**

 * GST_STATE_TRANSITION_NEXT:

 * @trans: A #GstStateChange

 *

 * Given a state transition @trans, extract the next #GstState.

 */

#define GST_STATE_TRANSITION_NEXT(trans)        ((GstState)((trans)&0x7))

/**

 * GstStateChange:

 * @GST_STATE_CHANGE_NULL_TO_READY    : state change from NULL to READY.

 *   * The element must check if the resources it needs are available. Device

 *     sinks and -sources typically try to probe the device to constrain their

 *     caps.

 *   * The element opens the device (in case feature need to be probed).

 * @GST_STATE_CHANGE_READY_TO_PAUSED  : state change from READY to PAUSED.

 *   * The element pads are activated in order to receive data in PAUSED.

 *     Streaming threads are started.

 *   * Some elements might need to return %GST_STATE_CHANGE_ASYNC and complete

 *     the state change when they have enough information. It is a requirement

 *     for sinks to return %GST_STATE_CHANGE_ASYNC and complete the state change

 *     when they receive the first buffer or %GST_EVENT_EOS (preroll).

 *     Sinks also block the dataflow when in PAUSED.

 *   * A pipeline resets the running_time to 0.

 *   * Live sources return %GST_STATE_CHANGE_NO_PREROLL and don't generate data.

 * @GST_STATE_CHANGE_PAUSED_TO_PLAYING: state change from PAUSED to PLAYING.

 *   * Most elements ignore this state change.

 *   * The pipeline selects a #GstClock and distributes this to all the children

 *     before setting them to PLAYING. This means that it is only allowed to

 *     synchronize on the #GstClock in the PLAYING state.

 *   * The pipeline uses the #GstClock and the running_time to calculate the

 *     base_time. The base_time is distributed to all children when performing

 *     the state change.

 *   * Sink elements stop blocking on the preroll buffer or event and start

 *     rendering the data.

 *   * Sinks can post %GST_MESSAGE_EOS in the PLAYING state. It is not allowed

 *     to post %GST_MESSAGE_EOS when not in the PLAYING state.

 *   * While streaming in PAUSED or PLAYING elements can create and remove

 *     sometimes pads.

 *   * Live sources start generating data and return %GST_STATE_CHANGE_SUCCESS.

 * @GST_STATE_CHANGE_PLAYING_TO_PAUSED: state change from PLAYING to PAUSED.

 *   * Most elements ignore this state change.

 *   * The pipeline calculates the running_time based on the last selected

 *     #GstClock and the base_time. It stores this information to continue

 *     playback when going back to the PLAYING state.

 *   * Sinks unblock any #GstClock wait calls.

 *   * When a sink does not have a pending buffer to play, it returns

 *     #GST_STATE_CHANGE_ASYNC from this state change and completes the state

 *     change when it receives a new buffer or an %GST_EVENT_EOS.

 *   * Any queued %GST_MESSAGE_EOS items are removed since they will be reposted

 *     when going back to the PLAYING state. The EOS messages are queued in

 *     #GstBin containers.

 *   * Live sources stop generating data and return %GST_STATE_CHANGE_NO_PREROLL.

 * @GST_STATE_CHANGE_PAUSED_TO_READY  : state change from PAUSED to READY.

 *   * Sinks unblock any waits in the preroll.

 *   * Elements unblock any waits on devices

 *   * Chain or get_range functions return %GST_FLOW_FLUSHING.

 *   * The element pads are deactivated so that streaming becomes impossible and

 *     all streaming threads are stopped.

 *   * The sink forgets all negotiated formats

 *   * Elements remove all sometimes pads

 * @GST_STATE_CHANGE_READY_TO_NULL    : state change from READY to NULL.

 *   * Elements close devices

 *   * Elements reset any internal state.

 * @GST_STATE_CHANGE_NULL_TO_NULL       : state change from NULL to NULL. (Since 1.14)

 * @GST_STATE_CHANGE_READY_TO_READY     : state change from READY to READY,

 * This might happen when going to PAUSED asynchronously failed, in that case

 * elements should make sure they are in a proper, coherent READY state. (Since 1.14)

 * @GST_STATE_CHANGE_PAUSED_TO_PAUSED   : state change from PAUSED to PAUSED.

 * This might happen when elements were in PLAYING state and 'lost state',

 * they should make sure to go back to real 'PAUSED' state (prerolling for example). (Since 1.14)

 * @GST_STATE_CHANGE_PLAYING_TO_PLAYING : state change from PLAYING to PLAYING. (Since 1.14)

 *

 * These are the different state changes an element goes through.

 * %GST_STATE_NULL ⇒ %GST_STATE_PLAYING is called an upwards state change

 * and %GST_STATE_PLAYING ⇒ %GST_STATE_NULL a downwards state change.

 */

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,

  GST_STATE_CHANGE_NULL_TO_NULL         = (GST_STATE_NULL<<3) | GST_STATE_NULL,

  GST_STATE_CHANGE_READY_TO_READY       = (GST_STATE_READY<<3) | GST_STATE_READY,

  GST_STATE_CHANGE_PAUSED_TO_PAUSED     = (GST_STATE_PAUSED<<3) | GST_STATE_PAUSED,

  GST_STATE_CHANGE_PLAYING_TO_PLAYING   = (GST_STATE_PLAYING<<3) | GST_STATE_PLAYING

} GstStateChange;

/**

 * GstElementFlags:

 * @GST_ELEMENT_FLAG_LOCKED_STATE: ignore state changes from parent

 * @GST_ELEMENT_FLAG_SINK: the element is a sink

 * @GST_ELEMENT_FLAG_SOURCE: the element is a source.

 * @GST_ELEMENT_FLAG_PROVIDE_CLOCK: the element can provide a clock

 * @GST_ELEMENT_FLAG_REQUIRE_CLOCK: the element requires a clock

 * @GST_ELEMENT_FLAG_INDEXABLE: the element can use an index

 * @GST_ELEMENT_FLAG_LAST: offset to define more flags

 *

 * The standard flags that an element may have.

 */

typedef enum

{

  GST_ELEMENT_FLAG_LOCKED_STATE   = (GST_OBJECT_FLAG_LAST << 0),

  GST_ELEMENT_FLAG_SINK           = (GST_OBJECT_FLAG_LAST << 1),

  GST_ELEMENT_FLAG_SOURCE         = (GST_OBJECT_FLAG_LAST << 2),

  GST_ELEMENT_FLAG_PROVIDE_CLOCK  = (GST_OBJECT_FLAG_LAST << 3),

  GST_ELEMENT_FLAG_REQUIRE_CLOCK  = (GST_OBJECT_FLAG_LAST << 4),

  GST_ELEMENT_FLAG_INDEXABLE      = (GST_OBJECT_FLAG_LAST << 5),

  /* padding */

  GST_ELEMENT_FLAG_LAST           = (GST_OBJECT_FLAG_LAST << 10)

} 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_FLAG_LOCKED_STATE))

/**

 * GST_ELEMENT_NAME:

 * @elem: A #GstElement to query

 *

 * Gets the name of this element. This is not thread-safe by default

 * (i.e. you will have to make sure the object lock is taken yourself).

 * If in doubt use gst_element_get_name() instead.

 */

#define GST_ELEMENT_NAME(elem)                  (GST_OBJECT_NAME(elem))

/**

 * GST_ELEMENT_PARENT:

 * @elem: A #GstElement to query

 *

 * Get the parent object of this element. This is not thread-safe by default

 * (i.e. you will have to make sure the object lock is taken yourself).

 * If in doubt use gst_object_get_parent() instead.

 */

#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. This is not thread-safe by default

 * (i.e. you will have to make sure the object lock is taken yourself).

 * If in doubt use gst_element_get_bus() instead.

 */

#define GST_ELEMENT_BUS(elem)                   (GST_ELEMENT_CAST(elem)->bus)

/**

 * GST_ELEMENT_CLOCK:

 * @elem: A #GstElement to query

 *

 * Get the clock of this element.This is not thread-safe by default

 * (i.e. you will have to make sure it is safe yourself).

 * If in doubt use gst_element_get_clock() instead.

 */

#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_START_TIME:

 * @elem: a #GstElement to return the start time for.

 *

 * This macro returns the start_time of the @elem. The start_time is the

 * running_time of the pipeline when the element went to PAUSED.

 */

#define GST_ELEMENT_START_TIME(elem)            (GST_ELEMENT_CAST(elem)->start_time)

GST_API

GstStructure *gst_make_element_message_details (const char *name, ...);

#define GST_ELEMENT_MESSAGE_MAKE_DETAILS(args) gst_make_element_message_details args

/**

 * GST_ELEMENT_FLOW_ERROR:

 * @el:           the element that generates the error

 * @flow_return:  the GstFlowReturn leading to that ERROR message

 *

 * Utility function that elements can use in case they encountered a fatal

 * data processing error due to wrong flow processing.

 *

 * Since: 1.10

 */

#define GST_ELEMENT_FLOW_ERROR(el,flow_return)  \

G_STMT_START {                                                          \

  GST_ELEMENT_ERROR_WITH_DETAILS (el, STREAM, FAILED, \

      ("Internal data stream error."), \

      ("streaming stopped, reason %s (%d)", gst_flow_get_name (flow_return), flow_return), \

      ("flow-return", G_TYPE_INT, flow_return, NULL));\

} G_STMT_END

/**

 * GST_ELEMENT_ERROR_WITH_DETAILS:

 * @el:     the element that generates the error

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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)

 * @args:   optional name, type, value triplets, which will be stored

 *          in the associated GstStructure. NULL terminator required.

 *          Must be enclosed within parentheses.

 *

 * Utility function that elements can use in case they encountered a fatal

 * data processing error. The pipeline will post an error message and the

 * application will be requested to stop further media processing.

 *

 * Since: 1.10

 */

#define GST_ELEMENT_ERROR_WITH_DETAILS(el,domain,code,text,debug,args)  \

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_with_details (GST_ELEMENT(el),               \

    GST_MESSAGE_ERROR, GST_ ## domain ## _ERROR,                        \

      GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__,        \

      GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args));  \

} G_STMT_END

/**

 * GST_ELEMENT_ERROR:

 * @el:     the element that generates the error

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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 post an error message 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_WITH_DETAILS:

 * @el:     the element that generates the warning

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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)

 * @args:   optional name, type, value triplets, which will be stored

 *          in the associated GstStructure. NULL terminator required.

 *          Must be enclosed within parentheses.

 *

 * Utility function that elements can use in case they encountered a non-fatal

 * data processing problem. The pipeline will post a warning message and the

 * application will be informed.

 *

 * Since: 1.10

 */

#define GST_ELEMENT_WARNING_WITH_DETAILS(el, domain, code, text, debug, args)\

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_with_details (GST_ELEMENT(el),               \

    GST_MESSAGE_WARNING, GST_ ## domain ## _ERROR,                      \

    GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__,          \

    GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args));    \

} G_STMT_END

/**

 * GST_ELEMENT_WARNING:

 * @el:     the element that generates the warning

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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 post a warning message 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

/**

 * GST_ELEMENT_INFO_WITH_DETAILS:

 * @el:     the element that generates the information

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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)

 * @args:   optional name, type, value triplets, which will be stored

 *          in the associated GstStructure. NULL terminator required.

 *          Must be enclosed within parentheses.

 *

 * Utility function that elements can use in case they want to inform

 * the application of something noteworthy that is not an error.

 * The pipeline will post a info message and the

 * application will be informed.

 * Optional name, type, value triplets may be supplied, and will be stored

 * in the associated GstStructure. NULL terminator required.

 *

 * Since: 1.10

 */

#define GST_ELEMENT_INFO_WITH_DETAILS(el, domain, code, text, debug, args)   \

G_STMT_START {                                                          \

  gchar *__txt = _gst_element_error_printf text;                        \

  gchar *__dbg = _gst_element_error_printf debug;                       \

  if (__txt)                                                            \

    GST_INFO_OBJECT (el, "info: %s", __txt);                            \

  if (__dbg)                                                            \

    GST_INFO_OBJECT (el, "info: %s", __dbg);                            \

  gst_element_message_full_with_details (GST_ELEMENT(el),               \

    GST_MESSAGE_INFO, GST_ ## domain ## _ERROR,                         \

    GST_ ## domain ## _ERROR_ ## code, __txt, __dbg, __FILE__,          \

    GST_FUNCTION, __LINE__, GST_ELEMENT_MESSAGE_MAKE_DETAILS(args));    \

} G_STMT_END

/**

 * GST_ELEMENT_INFO:

 * @el:     the element that generates the information

 * @domain: like CORE, LIBRARY, RESOURCE or STREAM (see #gstreamer-GstGError)

 * @code:   error code defined for that domain (see #gstreamer-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 want to inform

 * the application of something noteworthy that is not an error.

 * The pipeline will post a info message and the

 * application will be informed.

 */

#define GST_ELEMENT_INFO(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_INFO_OBJECT (el, "info: %s", __txt);                            \

  if (__dbg)                                                            \

    GST_INFO_OBJECT (el, "info: %s", __dbg);                            \

  gst_element_message_full (GST_ELEMENT(el),                            \

    GST_MESSAGE_INFO, 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_rec_mutex_lock(GST_STATE_GET_LOCK(elem))

#define GST_STATE_TRYLOCK(elem)                g_rec_mutex_trylock(GST_STATE_GET_LOCK(elem))

#define GST_STATE_UNLOCK(elem)                 g_rec_mutex_unlock(GST_STATE_GET_LOCK(elem))

#define GST_STATE_WAIT(elem)                   g_cond_wait (GST_STATE_GET_COND (elem), \

                                                        GST_OBJECT_GET_LOCK (elem))

#define GST_STATE_WAIT_UNTIL(elem, end_time)   g_cond_wait_until (GST_STATE_GET_COND (elem), \

                                                        GST_OBJECT_GET_LOCK (elem), end_time)

#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()

 * @target_state: the target state of an element as set by the application

 * @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 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 running_time against the clock.

 * @start_time: the running_time of the last PAUSED state

 * @numpads: number of pads of the element, includes both source and sink pads.

 * @pads: (element-type Gst.Pad): list of pads

 * @numsrcpads: number of source pads of the element.

 * @srcpads: (element-type Gst.Pad): list of source pads

 * @numsinkpads: number of sink pads of the element.

 * @sinkpads: (element-type Gst.Pad): list of sink pads

 * @pads_cookie: updated whenever the a pad is added or removed

 * @contexts: (element-type Gst.Context): list of contexts

 *

 * GStreamer element abstract base class.

 */

struct _GstElement

{

  GstObject             object;

  /*< public >*/ /* with LOCK */

  GRecMutex             state_lock;

  /* element state */

  GCond                 state_cond;

  guint32               state_cookie;

  GstState              target_state;

  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 */

  GstClockTime          start_time;

  /* 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;

  /* with object LOCK */

  GList                *contexts;

  /*< private >*/

  gpointer _gst_reserved[GST_PADDING-1];

};

/**

 * GstElementClass:

 * @parent_class: the parent class structure

 * @metadata: metadata 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

 * @send_event: send a #GstEvent to the element

 * @query: perform a #GstQuery on the element

 * @state_changed: called immediately after a new state was set.

 * @post_message: called when a message is posted on the element. Chain up to

 *                the parent class' handler to have it posted on the bus.

 * @set_context: set a #GstContext on the element

 *

 * GStreamer element class. Override the vmethods to implement the element

 * functionality.

 */

struct _GstElementClass

{

  GstObjectClass         parent_class;

  /*< public >*/

  /* the element metadata */

  gpointer		 metadata;

  /* 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 (*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 */

  /* FIXME 2.0 harmonize naming with gst_element_request_pad */

  GstPad*               (*request_new_pad)      (GstElement *element, GstPadTemplate *templ,

                                                 const gchar* name, const GstCaps *caps);

  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);

  void                 (*state_changed)         (GstElement *element, GstState oldstate,

                                                 GstState newstate, GstState pending);

  /* bus */

  void                  (*set_bus)              (GstElement * element, GstBus * bus);

  /* set/get clocks */

  GstClock*             (*provide_clock)        (GstElement *element);

  gboolean              (*set_clock)            (GstElement *element, GstClock *clock);

  /* query functions */

  gboolean              (*send_event)           (GstElement *element, GstEvent *event);

  gboolean              (*query)                (GstElement *element, GstQuery *query);

  gboolean              (*post_message)         (GstElement *element, GstMessage *message);

  void                  (*set_context)          (GstElement *element, GstContext *context);

  /*< private >*/

  gpointer _gst_reserved[GST_PADDING_LARGE-2];

};

/* element class pad templates */

GST_API

void                    gst_element_class_add_pad_template      (GstElementClass *klass, GstPadTemplate *templ);

GST_API

void                    gst_element_class_add_static_pad_template (GstElementClass *klass, GstStaticPadTemplate *static_templ);

GST_API

void                    gst_element_class_add_static_pad_template_with_gtype (GstElementClass *klass,

                                                                              GstStaticPadTemplate *static_templ,

                                                                              GType pad_type);

GST_API

GstPadTemplate*         gst_element_class_get_pad_template      (GstElementClass *element_class, const gchar *name);

GST_API

GList*                  gst_element_class_get_pad_template_list (GstElementClass *element_class);

/* element class meta data */

GST_API

void                    gst_element_class_set_metadata          (GstElementClass *klass,

                                                                 const gchar     *longname,

                                                                 const gchar     *classification,

                                                                 const gchar     *description,

                                                                 const gchar     *author);

GST_API

void                    gst_element_class_set_static_metadata   (GstElementClass *klass,

                                                                 const gchar     *longname,

                                                                 const gchar     *classification,

                                                                 const gchar     *description,

                                                                 const gchar     *author);

GST_API

void                    gst_element_class_add_metadata          (GstElementClass * klass,

                                                                 const gchar * key, const gchar * value);

GST_API

void                    gst_element_class_add_static_metadata   (GstElementClass * klass,

                                                                 const gchar * key, const gchar * value);

GST_API

const gchar *           gst_element_class_get_metadata          (GstElementClass * klass,

                                                                 const gchar * key);

/* element instance */

GST_API

GType                   gst_element_get_type            (void);

/* basic name and parentage stuff from GstObject */

/**

 * gst_element_get_name:

 * @elem: a #GstElement to get the name of @elem.

 *

 * Returns a copy of the name of @elem.

 * Caller should g_free() the return value after usage.

 * For a nameless element, this returns %NULL, which you can safely g_free()

 * as well.

 *

 * Returns: (transfer full) (nullable): the name of @elem. g_free()

 * after usage. MT safe.

 *

 */

#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.

 *

 * Get the parent of an element.

 *

 * Returns: (transfer full): 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 */

GST_API

GstClock*               gst_element_provide_clock       (GstElement *element);

GST_API

GstClock*               gst_element_get_clock           (GstElement *element);

GST_API

gboolean                gst_element_set_clock           (GstElement *element, GstClock *clock);

GST_API

void                    gst_element_set_base_time       (GstElement *element, GstClockTime time);

GST_API

GstClockTime            gst_element_get_base_time       (GstElement *element);

GST_API

void                    gst_element_set_start_time      (GstElement *element, GstClockTime time);

GST_API

GstClockTime            gst_element_get_start_time      (GstElement *element);

/* bus */

GST_API

void                    gst_element_set_bus             (GstElement * element, GstBus * bus);

GST_API

GstBus *                gst_element_get_bus             (GstElement * element);

/* context */

GST_API

void                    gst_element_set_context         (GstElement * element, GstContext * context);

GST_API

GList *                 gst_element_get_contexts        (GstElement * element);

GST_API

GstContext *            gst_element_get_context         (GstElement * element, const gchar * context_type);