gstreamer/gst/gstiterator.h
Niels De Graef 09141c6e1f Use G_DEFINE_AUTOPTR_CLEANUP_FUNC unconditionally
Since we started depending on GLib 2.44, we can be sure this macro is
defined (it will be a no-op on compilers that don't support it). For
plugins we should just start using `G_DECLARE_FINAL_TYPE` which means
we no longer need the macro there, but for most types in core we don't
want to break ABI, which means it's better to just keep it like it is
(and use the `#ifdef` instead).
2019-06-04 08:50:59 +02:00

291 lines
10 KiB
C

/* GStreamer
* Copyright (C) 2004 Wim Taymans <wim@fluendo.com>
* Copyright (C) 2011 Sebastian Dröge <sebastian.droege@collabora.co.uk>
*
* gstiterator.h: Header for GstIterator
*
* 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_ITERATOR_H__
#define __GST_ITERATOR_H__
#include <glib-object.h> /* for GValue in the fold */
#include <gst/gstconfig.h>
G_BEGIN_DECLS
#define GST_TYPE_ITERATOR (gst_iterator_get_type ())
/**
* GstIteratorResult:
* @GST_ITERATOR_DONE: No more items in the iterator
* @GST_ITERATOR_OK: An item was retrieved
* @GST_ITERATOR_RESYNC: Datastructure changed while iterating
* @GST_ITERATOR_ERROR: An error happened
*
* The result of gst_iterator_next().
*/
typedef enum {
GST_ITERATOR_DONE = 0,
GST_ITERATOR_OK = 1,
GST_ITERATOR_RESYNC = 2,
GST_ITERATOR_ERROR = 3
} GstIteratorResult;
typedef struct _GstIterator GstIterator;
/**
* GstIteratorItem:
* @GST_ITERATOR_ITEM_SKIP: Skip this item
* @GST_ITERATOR_ITEM_PASS: Return item
* @GST_ITERATOR_ITEM_END: Stop after this item.
*
* The result of a #GstIteratorItemFunction.
*/
typedef enum {
GST_ITERATOR_ITEM_SKIP = 0,
GST_ITERATOR_ITEM_PASS = 1,
GST_ITERATOR_ITEM_END = 2
} GstIteratorItem;
/**
* GstIteratorCopyFunction:
* @it: The original iterator
* @copy: The copied iterator
*
* This function will be called when creating a copy of @it and should
* create a copy of all custom iterator fields or increase their
* reference counts.
*/
typedef void (*GstIteratorCopyFunction) (const GstIterator *it, GstIterator *copy);
/**
* GstIteratorItemFunction:
* @it: the iterator
* @item: the item being retrieved.
*
* The function that will be called after the next item of the iterator
* has been retrieved. This function can be used to skip items or stop
* the iterator.
*
* The function will be called with the iterator lock held.
*
* Returns: the result of the operation.
*/
typedef GstIteratorItem (*GstIteratorItemFunction) (GstIterator *it, const GValue * item);
/**
* GstIteratorNextFunction:
* @it: the iterator
* @result: a pointer to hold the next item
*
* The function that will be called when the next element of the iterator
* should be retrieved.
*
* Implementors of a #GstIterator should implement this
* function and pass it to the constructor of the custom iterator.
* The function will be called with the iterator lock held.
*
* Returns: the result of the operation.
*/
typedef GstIteratorResult (*GstIteratorNextFunction) (GstIterator *it, GValue *result);
/**
* GstIteratorResyncFunction:
* @it: the iterator
*
* This function will be called whenever a concurrent update happened
* to the iterated datastructure. The implementor of the iterator should
* restart the iterator from the beginning and clean up any state it might
* have.
*
* Implementors of a #GstIterator should implement this
* function and pass it to the constructor of the custom iterator.
* The function will be called with the iterator lock held.
*/
typedef void (*GstIteratorResyncFunction) (GstIterator *it);
/**
* GstIteratorFreeFunction:
* @it: the iterator
*
* This function will be called when the iterator is freed.
*
* Implementors of a #GstIterator should implement this
* function and pass it to the constructor of the custom iterator.
* The function will be called with the iterator lock held.
*/
typedef void (*GstIteratorFreeFunction) (GstIterator *it);
/**
* GstIteratorForeachFunction:
* @item: The item
* @user_data: User data
*
* A function that is called by gst_iterator_foreach() for every element.
*/
typedef void (*GstIteratorForeachFunction) (const GValue * item, gpointer user_data);
/**
* GstIteratorFoldFunction:
* @item: the item to fold
* @ret: a #GValue collecting the result
* @user_data: data passed to gst_iterator_fold()
*
* A function to be passed to gst_iterator_fold().
*
* Returns: %TRUE if the fold should continue, %FALSE if it should stop.
*/
typedef gboolean (*GstIteratorFoldFunction) (const GValue * item, GValue * ret, gpointer user_data);
/**
* GST_ITERATOR:
* @it: the #GstIterator value
*
* Macro to cast to a #GstIterator
*/
#define GST_ITERATOR(it) ((GstIterator*)(it))
/**
* GST_ITERATOR_LOCK:
* @it: the #GstIterator to get the lock of
*
* Macro to get the lock protecting the datastructure being iterated.
*/
#define GST_ITERATOR_LOCK(it) (GST_ITERATOR(it)->lock)
/**
* GST_ITERATOR_COOKIE:
* @it: the #GstIterator to get the cookie of
*
* Macro to get the cookie of a #GstIterator. The cookie of the
* iterator is the value of the master cookie when the iterator
* was created.
* Whenever the iterator is iterated, the value is compared to the
* value of the master cookie. If they are different, a concurrent
* modification happened to the iterator and a resync is needed.
*/
#define GST_ITERATOR_COOKIE(it) (GST_ITERATOR(it)->cookie)
/**
* GST_ITERATOR_ORIG_COOKIE:
* @it: the #GstIterator to get the master cookie of
*
* Macro to get a pointer to where the master cookie is stored. The
* master cookie protects the structure being iterated and gets updated
* whenever the datastructure changes.
*/
#define GST_ITERATOR_ORIG_COOKIE(it) (GST_ITERATOR(it)->master_cookie)
/**
* GstIterator:
* @copy: The function to copy the iterator
* @next: The function to get the next item in the iterator
* @item: The function to be called for each item retrieved
* @resync: The function to call when a resync is needed.
* @free: The function to call when the iterator is freed
* @pushed: The iterator that is currently pushed with gst_iterator_push()
* @type: The type of the object that this iterator will return
* @lock: The lock protecting the data structure and the cookie.
* @cookie: The cookie; the value of the master_cookie when this iterator was
* created.
* @master_cookie: A pointer to the master cookie.
* @size: the size of the iterator
*
* #GstIterator base structure. The values of this structure are
* protected for subclasses, use the methods to use the #GstIterator.
*/
struct _GstIterator {
/*< protected >*/
GstIteratorCopyFunction copy;
GstIteratorNextFunction next;
GstIteratorItemFunction item;
GstIteratorResyncFunction resync;
GstIteratorFreeFunction free;
GstIterator *pushed; /* pushed iterator */
GType type;
GMutex *lock;
guint32 cookie; /* cookie of the iterator */
guint32 *master_cookie; /* pointer to guint32 holding the cookie when this
iterator was created */
guint size;
/*< private >*/
gpointer _gst_reserved[GST_PADDING];
};
GST_API
GType gst_iterator_get_type (void);
/* creating iterators */
GST_API
GstIterator* gst_iterator_new (guint size,
GType type,
GMutex *lock,
guint32 *master_cookie,
GstIteratorCopyFunction copy,
GstIteratorNextFunction next,
GstIteratorItemFunction item,
GstIteratorResyncFunction resync,
GstIteratorFreeFunction free) G_GNUC_MALLOC;
GST_API
GstIterator* gst_iterator_new_list (GType type,
GMutex *lock,
guint32 *master_cookie,
GList **list,
GObject * owner,
GstIteratorItemFunction item) G_GNUC_MALLOC;
GST_API
GstIterator* gst_iterator_new_single (GType type,
const GValue * object) G_GNUC_MALLOC;
GST_API
GstIterator* gst_iterator_copy (const GstIterator *it) G_GNUC_MALLOC;
/* using iterators */
GST_API
GstIteratorResult gst_iterator_next (GstIterator *it, GValue * elem);
GST_API
void gst_iterator_resync (GstIterator *it);
GST_API
void gst_iterator_free (GstIterator *it);
GST_API
void gst_iterator_push (GstIterator *it, GstIterator *other);
/* higher-order functions that operate on iterators */
GST_API
GstIterator* gst_iterator_filter (GstIterator *it, GCompareFunc func,
const GValue * user_data) G_GNUC_MALLOC;
GST_API
GstIteratorResult gst_iterator_fold (GstIterator *it,
GstIteratorFoldFunction func,
GValue *ret, gpointer user_data);
GST_API
GstIteratorResult gst_iterator_foreach (GstIterator *it,
GstIteratorForeachFunction func, gpointer user_data);
GST_API
gboolean gst_iterator_find_custom (GstIterator *it, GCompareFunc func,
GValue *elem, gpointer user_data);
G_DEFINE_AUTOPTR_CLEANUP_FUNC(GstIterator, gst_iterator_free)
G_END_DECLS
#endif /* __GST_ITERATOR_H__ */