The object the SignalTracker belongs to is stored in a map managed by
the SignalManager which keeps a reference to that object. This map is
never destroyed nor is any entry ever removed. This leads to all objects
that ever had SignalTrackers used on them being kept alive even after
all references outside of the SignalTracker are long gone. This then
also extends to other objects which are leaked indirectly through
reference chains from these objects.
And if some of those objects are GObjects, this will prevent them from
being finalized, leaking further resources. A StWidget for example will
not release its shadow textures.
Fix this by using a WeakMap in SignalManager.
Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5807
Closes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/5796
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2450>
We considered any ConnectFlag value major than SWAPPED as invalid, while
it's technically not fully true as we need to ensure that the passed
value is respecting the whole flags mask.
In fact, per se SWAPPED|AFTER (> SWAPPED) is a valid value (even if we
don't support the AFTER value).
But this makes the check more future-proof.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2366>
While untracking an object we used to compute it's proto for each signal
we were disconnecting from, while this is not needed when we're just
iterating over all the same owner signals, so let's add few more
functions to compute an object prototype, and repeat the disconnections
in the simplest way we can.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2366>
We used to create a temporary array of signal tracker keys and then to
iterate through them in order to untrack the objects, but the Map's can
be iterated directly so let's just use their native forEach.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2366>
Introduce a new class, EventEmitter, which implements signal
handling for pure JavaScript classes. EventEmitter still
utilizes GJS' addSignalMethods internally.
EventEmitter allows static typechecking to understand the
structure of event-emitting JS classes and makes creating
child classes simpler.
The name 'EventEmitter' mirrors a common name for this pattern
in Node and in JS libraries.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2043>
We currently assume that any '::destroy' signal on a GObject type
has the semantics of the ClutterActor/GtkWidget signal, and should
therefore result in all signals being disconnected.
But we already have a case where the assumption doesn't hold: ShellWM
uses '::destroy' for the closing animation of windows, and the ShellWM
object itself remains very valid after the emission.
So rather than making assumptions about '::destroy', check objects
against a list of destroyable types that are explicitly registered
as such.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2226>
There are cases where we want to connect to a number of signals
for the lifetime of an object, but also other signals for a
limited period (say: between show and hide).
It is currently not possible to use disconnectObject() for the
latter, because it will disconnect all signals.
To address this use case, add a small class that can be used as
a transient signal holder, while still benefiting from autocleanup
by proxying the real owner.
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2221>
The 'destroy' signal currently doesn't work with connectObject(),
because the handler is only connected after the signal tracker's
own destroy handler, which disconnects all handlers.
Address this by using connect_after for the cleanup handler, so
that other destroy handlers run before it (unless they also use
ConnectFlags.AFTER, but well *shrug*).
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/2221>
The module exports a `addObjectSignalMethods()` method that extends
the provided prototype with `connectObject()` and `disconnectObject()`
methods.
In its simplest form, `connectObject()` looks like the regular
`connect()` method, except for an additional parameter:
```js
this._button.connectObject('clicked',
() => this._onButtonClicked(), this);
```
The additional object can be used to disconnect all handlers on the
instance that were connected with that object, similar to
`g_signal_handlers_disconnect_by_data()` (which cannot be used
from introspection).
For objects that are subclasses of Clutter.Actor, that will happen
automatically when the actor is destroyed, similar to
`g_signal_connect_object()`.
Finally, `connectObject()` allows to conveniently connect multiple
signals at once, similar to `g_object_connect()`:
```js
this._toggleButton.connect(
'clicked', () => this._onClicked(),
'notify::checked', () => this._onChecked(), this);
```
Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1953>
