Iterator

A GstIterator is used to retrieve multiple objects from another object in a threadsafe way.

Various GStreamer objects provide access to their internal structures using an iterator.

Note that if calling a GstIterator function results in your code receiving a refcounted object (with, say, g_value_get_object()), the refcount for that object will not be increased. Your code is responsible for taking a reference if it wants to continue using it later.

The basic use pattern of an iterator is as follows: |[ GstIterator *it = _get_iterator(object); GValue item = G_VALUE_INIT; done = FALSE; while (!done) { switch (gst_iterator_next (it, &item)) { case GST_ITERATOR_OK: ...get/use/change item here... g_value_reset (&item); break; case GST_ITERATOR_RESYNC: ...rollback changes to items... gst_iterator_resync (it); break; case GST_ITERATOR_ERROR: ...wrong parameters were given... done = TRUE; break; case GST_ITERATOR_DONE: done = TRUE; break; } } g_value_unset (&item); gst_iterator_free (it); ]|

class Iterator {

protected

GstIterator* gstIterator;

protected

bool ownedRef;

GstIterator* getIteratorStruct();

void* getStruct();

this(GstIterator* gstIterator, bool ownedRef);

static GType getType();

this(uint size, GType type, Mutex lock, uint* masterCookie, GstIteratorCopyFunction copy, GstIteratorNextFunction next, GstIteratorItemFunction item, GstIteratorResyncFunction resync, GstIteratorFreeFunction free);

this(GType type, Mutex lock, uint* masterCookie, ListG list, ObjectG owner, GstIteratorItemFunction item);

this(GType type, Value object);

Iterator copy();

Iterator filter(GCompareFunc func, Value userData);

bool findCustom(GCompareFunc func, Value elem, void* userData);

GstIteratorResult fold(GstIteratorFoldFunction func, Value ret, void* userData);

GstIteratorResult foreac(GstIteratorForeachFunction func, void* userData);

void free();

GstIteratorResult next(Value elem);

void push(Iterator other);

void resync();

}

Constructors

this this(GstIterator* gstIterator, bool ownedRef): Sets our main struct and passes it to the parent class.
this this(uint size, GType type, Mutex lock, uint* masterCookie, GstIteratorCopyFunction copy, GstIteratorNextFunction next, GstIteratorItemFunction item, GstIteratorResyncFunction resync, GstIteratorFreeFunction free): Create a new iterator. This function is mainly used for objects implementing the next/resync/free function to iterate a data structure.
this this(GType type, Mutex lock, uint* masterCookie, ListG list, ObjectG owner, GstIteratorItemFunction item): Create a new iterator designed for iterating @list.
this this(GType type, Value object): This #GstIterator is a convenient iterator for the common case where a #GstIterator needs to be returned but only a single object has to be considered. This happens often for the #GstPadIterIntLinkFunction.

Members

Functions

copy Iterator copy(): Copy the iterator and its state.
filter Iterator filter(GCompareFunc func, Value userData): Create a new iterator from an existing iterator. The new iterator will only return those elements that match the given compare function @func. The first parameter that is passed to @func is the #GValue of the current iterator element and the second parameter is @user_data. @func should return 0 for elements that should be included in the filtered iterator.
findCustom bool findCustom(GCompareFunc func, Value elem, void* userData): Find the first element in @it that matches the compare function @func. @func should return 0 when the element is found. The first parameter to @func will be the current element of the iterator and the second parameter will be @user_data. The result will be stored in @elem if a result is found.
fold GstIteratorResult fold(GstIteratorFoldFunction func, Value ret, void* userData): Folds @func over the elements of @iter. That is to say, @func will be called as @func (object, @ret, @user_data) for each object in @it. The normal use of this procedure is to accumulate the results of operating on the objects in @ret.
foreac GstIteratorResult foreac(GstIteratorForeachFunction func, void* userData): Iterate over all element of @it and call the given function @func for each element.
free void free(): Free the iterator.
getIteratorStruct GstIterator* getIteratorStruct(): Get the main Gtk struct
getStruct void* getStruct(): the main Gtk struct as a void*
next GstIteratorResult next(Value elem): Get the next item from the iterator in @elem.
push void push(Iterator other): Pushes @other iterator onto @it. All calls performed on @it are forwarded to @other. If @other returns %GST_ITERATOR_DONE, it is popped again and calls are handled by @it again.
resync void resync(): Resync the iterator. this function is mostly called after gst_iterator_next() returned %GST_ITERATOR_RESYNC.

Static functions

getType GType getType()

Variables

gstIterator GstIterator* gstIterator;: the main Gtk struct
ownedRef bool ownedRef;: Undocumented in source.