gstreamer/gst/gstbin.h
Mathieu Duponchelle 69c790c025 docs: standardize GstBin documentation
* Don't mention explicitly that API is MT safe, this implies that
  other API is not. GStreamer API is assumed to be MT safe, thread
  safety should only be explicitly mentioned when API is *not* MT safe

* Don't repeat what annotations are stating with respect to ownership
  transfer, nullability

* Document virtual methods in standalone comments, so that parameters
  can be documented. This is not critical here, as parameters do not
  need annotations / specific documentation, but serves as an up to
  date example

* Document enumeration members in standalone comments, so that their
  Since tag is accounted for by gobject-introspection

* Misc cleanup / typo fixes / addition of links

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/747>
2021-02-04 16:21:38 +01:00

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C

/* GStreamer
* Copyright (C) 1999,2000 Erik Walthinsen <omega@cse.ogi.edu>
* 2000 Wim Taymans <wtay@chello.be>
*
* gstbin.h: Header for GstBin container 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_BIN_H__
#define __GST_BIN_H__
#include <gst/gstelement.h>
#include <gst/gstiterator.h>
#include <gst/gstbus.h>
G_BEGIN_DECLS
#define GST_TYPE_BIN (gst_bin_get_type ())
#define GST_IS_BIN(obj) (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GST_TYPE_BIN))
#define GST_IS_BIN_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass), GST_TYPE_BIN))
#define GST_BIN_GET_CLASS(obj) (G_TYPE_INSTANCE_GET_CLASS ((obj), GST_TYPE_BIN, GstBinClass))
#define GST_BIN(obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), GST_TYPE_BIN, GstBin))
#define GST_BIN_CLASS(klass) (G_TYPE_CHECK_CLASS_CAST ((klass), GST_TYPE_BIN, GstBinClass))
#define GST_BIN_CAST(obj) ((GstBin*)(obj))
/**
* GstBinFlags:
* @GST_BIN_FLAG_LAST: the last enum in the series of flags for bins.
* Derived classes can use this as first value in a list of flags.
*
* GstBinFlags are a set of flags specific to bins. Most are set/used
* internally. They can be checked using the GST_OBJECT_FLAG_IS_SET() macro,
* and (un)set using GST_OBJECT_FLAG_SET() and GST_OBJECT_FLAG_UNSET().
*/
typedef enum {
/**
* GST_BIN_FLAG_NO_RESYNC:
*
* Don't resync a state change when elements are added or linked in the bin
*
* Since: 1.0.5
*/
GST_BIN_FLAG_NO_RESYNC = (GST_ELEMENT_FLAG_LAST << 0),
/**
* GST_BIN_FLAG_STREAMS_AWARE:
*
* Indicates whether the bin can handle elements that add/remove source pads
* at any point in time without first posting a no-more-pads signal.
*
* Since: 1.10
*/
GST_BIN_FLAG_STREAMS_AWARE = (GST_ELEMENT_FLAG_LAST << 1),
/* padding */
/**
* GST_BIN_FLAG_LAST:
*
* The last enum in the series of flags for bins. Derived classes can use this
* as first value in a list of flags.
*/
GST_BIN_FLAG_LAST = (GST_ELEMENT_FLAG_LAST << 5)
} GstBinFlags;
/**
* GST_BIN_IS_NO_RESYNC:
* @bin: A #GstBin
*
* Check if @bin will resync its state change when elements are added and
* removed.
*
* Since: 1.0.5
*/
#define GST_BIN_IS_NO_RESYNC(bin) (GST_OBJECT_FLAG_IS_SET(bin,GST_BIN_FLAG_NO_RESYNC))
typedef struct _GstBin GstBin;
typedef struct _GstBinClass GstBinClass;
typedef struct _GstBinPrivate GstBinPrivate;
/**
* GST_BIN_NUMCHILDREN:
* @bin: a #GstBin
*
* Gets the number of children in a bin.
*/
#define GST_BIN_NUMCHILDREN(bin) (GST_BIN_CAST(bin)->numchildren)
/**
* GST_BIN_CHILDREN:
* @bin: a #GstBin
*
* Gets the list of children in a bin.
*/
#define GST_BIN_CHILDREN(bin) (GST_BIN_CAST(bin)->children)
/**
* GST_BIN_CHILDREN_COOKIE:
* @bin: a #GstBin
*
* Gets the children cookie that watches the children list.
*/
#define GST_BIN_CHILDREN_COOKIE(bin) (GST_BIN_CAST(bin)->children_cookie)
/**
* GstBin:
* @numchildren: the number of children in this bin
* @children: (element-type Gst.Element): the list of children in this bin
* @children_cookie: updated whenever @children changes
* @child_bus: internal bus for handling child messages
* @messages: (element-type Gst.Message): queued and cached messages
* @polling: the bin is currently calculating its state
* @state_dirty: the bin needs to recalculate its state (deprecated)
* @clock_dirty: the bin needs to select a new clock
* @provided_clock: the last clock selected
* @clock_provider: the element that provided @provided_clock
*
* The GstBin base class. Subclasses can access these fields provided
* the LOCK is taken.
*/
struct _GstBin {
GstElement element;
/*< public >*/ /* with LOCK */
/* our children, subclass are supposed to update these
* fields to reflect their state with _iterate_*() */
gint numchildren;
GList *children;
guint32 children_cookie;
GstBus *child_bus;
GList *messages;
gboolean polling;
gboolean state_dirty;
gboolean clock_dirty;
GstClock *provided_clock;
GstElement *clock_provider;
/*< private >*/
GstBinPrivate *priv;
gpointer _gst_reserved[GST_PADDING];
};
/**
* GstBinClass:
* @parent_class: bin parent class
*
* Subclasses can override #GstBinClass::add_element and #GstBinClass::remove_element
* to update the list of children in the bin.
*
* The #GstBinClass::handle_message method can be overridden to implement custom
* message handling. handle_message takes ownership of the message, just like
* gst_element_post_message().
*
* #GstBinClass::deep_element_added will be called when a new element has been
* added to any bin inside this bin, so it will also be called if a new child
* was added to a sub-bin of this bin. #GstBin implementations that override
* this message should chain up to the parent class implementation so the
* #GstBin::deep-element-added signal is emitted on all parents.
*/
struct _GstBinClass {
GstElementClass parent_class;
/*< private >*/
GThreadPool *pool; /* deprecated */
/* signals */
/**
* GstBinClass::element_added:
* @bin: the #GstBin
* @child: the element that was added
*
* Method called when an element was added to the bin.
*/
void (*element_added) (GstBin *bin, GstElement *child);
/**
* GstBinClass::element_removed:
* @bin: the #GstBin
* @child: the element that was removed
*
* Method called when an element was removed from the bin.
*/
void (*element_removed) (GstBin *bin, GstElement *child);
/*< public >*/
/* virtual methods for subclasses */
/**
* GstBinClass::add_element:
* @bin: the #GstBin
* @element: the element to be added
*
* Method to add an element to the bin.
*
* Returns: %TRUE if the @element was added
*/
gboolean (*add_element) (GstBin *bin, GstElement *element);
/**
* GstBinClass::remove_element:
* @bin: the #GstBin
* @element: the element to be removed
*
* Method to remove an element from the bin.
*
* Returns: %TRUE if the @element was removed
*/
gboolean (*remove_element) (GstBin *bin, GstElement *element);
/**
* GstBinClass::handle_message:
* @bin: the #GstBin
* @message: the message to be handled
*
* Method to handle a message from the children.
*/
void (*handle_message) (GstBin *bin, GstMessage *message);
/*< private >*/
/* signal */
gboolean (*do_latency) (GstBin *bin);
/*< public >*/
/* signal */
/**
* GstBinClass::deep_element_added:
* @bin: the top level #GstBin
* @sub_bin: the #GstBin to which the element was added
* @child: the element that was added
*
* Method called when an element was added somewhere in the bin hierarchy.
*/
void (*deep_element_added) (GstBin *bin, GstBin *sub_bin, GstElement *child);
/**
* GstBinClass::deep_element_removed:
* @bin: the top level #GstBin
* @sub_bin: the #GstBin from which the element was removed
* @child: the element that was removed
*
* Method called when an element was removed somewhere in the bin hierarchy.
*/
void (*deep_element_removed) (GstBin *bin, GstBin *sub_bin, GstElement *child);
/*< private >*/
gpointer _gst_reserved[GST_PADDING-2];
};
GST_API
GType gst_bin_get_type (void);
GST_API
GstElement* gst_bin_new (const gchar *name);
/* add and remove elements from the bin */
GST_API
gboolean gst_bin_add (GstBin *bin, GstElement *element);
GST_API
gboolean gst_bin_remove (GstBin *bin, GstElement *element);
/* retrieve a single child */
GST_API
GstElement* gst_bin_get_by_name (GstBin *bin, const gchar *name);
GST_API
GstElement* gst_bin_get_by_name_recurse_up (GstBin *bin, const gchar *name);
GST_API
GstElement* gst_bin_get_by_interface (GstBin *bin, GType iface);
/* retrieve multiple children */
GST_API
GstIterator* gst_bin_iterate_elements (GstBin *bin);
GST_API
GstIterator* gst_bin_iterate_sorted (GstBin *bin);
GST_API
GstIterator* gst_bin_iterate_recurse (GstBin *bin);
GST_API
GstIterator* gst_bin_iterate_sinks (GstBin *bin);
GST_API
GstIterator* gst_bin_iterate_sources (GstBin *bin);
GST_API
GstIterator* gst_bin_iterate_all_by_interface (GstBin *bin, GType iface);
GST_API
GstIterator* gst_bin_iterate_all_by_element_factory_name (GstBin * bin, const gchar * factory_name);
/* latency */
GST_API
gboolean gst_bin_recalculate_latency (GstBin * bin);
/* set and get suppressed flags */
GST_API
void gst_bin_set_suppressed_flags (GstBin * bin, GstElementFlags flags);
GST_API
GstElementFlags gst_bin_get_suppressed_flags (GstBin * bin);
G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstBin, gst_object_unref)
G_END_DECLS
#endif /* __GST_BIN_H__ */