g_object_bind_property() (transfer none) returns a GBinding with an existing internal
reference which is active as long as the "binding" is. This allows to optionally use
the binding without any memory management, as it will remove itself when it is no longer
needed.
There are currently three ways to remove the "binding" and as a result the reference:
1) Either the source or target dies and we get notified by a weakref callback
2) The user unrefs the binding until it is destroyed (which is semi-legal,
but worked and is used in the test suite)
3) The user calls g_binding_unbind()
In case (3) the problem was that it always calls unref even if the "binding" is already
gone, leading to crashes when called from bindings multiple times.
In #1373 and !197 it was noticed that a function always unrefs which would be a
"transfer full" annotation, but the problem here is that it should only remove the
ref when removing the "binding" and the annotation should stay "transfer none".
As a side effect of this fix it is now also possible to call g_binding_unbind() multiple
times where every call after the first is a no-op.
This also adds explicit tests for case (1) and (3) - only case (3) is affected by this change.
This is for destroying resources needed by transformations. But the user
may not need any such resources. Make it obvious that, instead of having
to point to a no-op function, @notify is checked and not called if NULL.
https://bugzilla.gnome.org/show_bug.cgi?id=792098
It's unnecessary, and only adds visual noise; we have been fairly
inconsistent in the past, but the semi-colon-less version clearly
dominates in the code base.
https://bugzilla.gnome.org/show_bug.cgi?id=669355
If we have an input parameter (or return value) we need to use (nullable).
However, if it is an (inout) or (out) parameter, (optional) is sufficient.
It looks like (nullable) could be used for everything according to the
Annotation documentation, but (optional) is more specific.
It isn't actually doing anything, instead it is
being managed without actually being used.
This has the result that GBinding is now more
thread-safe.
https://bugzilla.gnome.org/show_bug.cgi?id=745013
GBindingTransformFunc called its arguments "source_value" and
"target_value", but in the transform_from function of a bidirectional
binding, "source_value" comes from the target object, and
"target_value" comes from the source object, which quickly gets
confusing if you need to use g_binding_get_source(), etc, in the
function.
Of course developers can call their transform function arguments
whatever they want, but many will copy from the headers/docs to start
out, so use less confusing names here ("from_value" and "to_value").
Also, fix the documentation to describe the bidirectional case
correctly.
https://bugzilla.gnome.org/show_bug.cgi?id=709440
The automatic memory management of GBinding is not optimal for high
order languages with garbage collectors semantics. If we leave the
binding instance inert but still referenced it will be leaked, so one
solution that does not throw away the baby of C convenience with the
bathwater of language bindability is to have unbind() perform an
implicit unref().
Hopefully, C developers will read the documentation and especially the
note that says that after calling unbind() the reference count on the
GBinding instance is decreased.
https://bugzilla.gnome.org/show_bug.cgi?id=698018
Higher order languages with garbage collection can have issues releasing
a binding, as they do not control the last reference being dropped on
the binding, source, or target instances.
https://bugzilla.gnome.org/show_bug.cgi?id=698018
The g_object_bind_property_with_closures() function should set a
marshaller if the two GClosures don't have one already. This simplifies
the caller code and avoids duplication.
We need to add a new marshaller to the gmarshal.list matching the
signature of the GBindingTransformFunc function.
Since GSettings got the same functionality and flag in commit ca3b7b75b
GBinding should also have the ability to automatically invert a boolean
value without requiring a custom transformation function.
Since using the function pointer version muddles the memory management
requirements of language bindings, we should implement a GClosure-based
variant on top of g_object_bind_property_full().
https://bugzilla.gnome.org/show_bug.cgi?id=622278
When creating a binding between two object properties we might want to
automatically synchronize the two values at the moment of the binding
creation, instead of waiting for the next change.
The G_BINDING_SYNC_CREATE flag does exactly what it says on the tin.
https://bugzilla.gnome.org/show_bug.cgi?id=622281
Since an object instance might have a lot of bindings, using a list
might become a performance issue when removing them. Using a simple
hash table guarantees constant time lookup, which is the most common
operation.
GBinding is a simple, opaque object that represents a binding between a
property on a GObject instance (source) and property on another GObject
instance (target).
https://bugzilla.gnome.org/show_bug.cgi?id=348080
