gnome-shell/js/ui/xdndHandler.js
Evan Welsh a88e59c1a8 Adopt EventEmitter class instead of injecting Signal methods
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>
2022-07-04 18:30:49 -04:00

117 lines
4.1 KiB
JavaScript

// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
/* exported XdndHandler */
const { Clutter } = imports.gi;
const Signals = imports.misc.signals;
const DND = imports.ui.dnd;
const Main = imports.ui.main;
var XdndHandler = class extends Signals.EventEmitter {
constructor() {
super();
// Used to display a clone of the cursor window when the
// window group is hidden (like it happens in the overview)
this._cursorWindowClone = null;
// Used as a drag actor in case we don't have a cursor window clone
this._dummy = new Clutter.Actor({ width: 1, height: 1, opacity: 0 });
Main.uiGroup.add_actor(this._dummy);
this._dummy.hide();
var dnd = global.backend.get_dnd();
dnd.connect('dnd-enter', this._onEnter.bind(this));
dnd.connect('dnd-position-change', this._onPositionChanged.bind(this));
dnd.connect('dnd-leave', this._onLeave.bind(this));
}
// Called when the user cancels the drag (i.e release the button)
_onLeave() {
global.window_group.disconnectObject(this);
if (this._cursorWindowClone) {
this._cursorWindowClone.destroy();
this._cursorWindowClone = null;
}
this.emit('drag-end');
}
_onEnter() {
global.window_group.connectObject('notify::visible',
this._onWindowGroupVisibilityChanged.bind(this), this);
this.emit('drag-begin', global.get_current_time());
}
_onWindowGroupVisibilityChanged() {
if (!global.window_group.visible) {
if (this._cursorWindowClone)
return;
let windows = global.get_window_actors();
let cursorWindow = windows[windows.length - 1];
// FIXME: more reliable way?
if (!cursorWindow.get_meta_window().is_override_redirect())
return;
const constraintPosition = new Clutter.BindConstraint({
coordinate: Clutter.BindCoordinate.POSITION,
source: cursorWindow,
});
this._cursorWindowClone = new Clutter.Clone({ source: cursorWindow });
Main.uiGroup.add_actor(this._cursorWindowClone);
// Make sure that the clone has the same position as the source
this._cursorWindowClone.add_constraint(constraintPosition);
} else {
if (!this._cursorWindowClone)
return;
this._cursorWindowClone.destroy();
this._cursorWindowClone = null;
}
}
_onPositionChanged(obj, x, y) {
let pickedActor = global.stage.get_actor_at_pos(Clutter.PickMode.REACTIVE, x, y);
// Make sure that the cursor window is on top
if (this._cursorWindowClone)
Main.uiGroup.set_child_above_sibling(this._cursorWindowClone, null);
let dragEvent = {
x,
y,
dragActor: this._cursorWindowClone ?? this._dummy,
source: this,
targetActor: pickedActor,
};
for (let i = 0; i < DND.dragMonitors.length; i++) {
let motionFunc = DND.dragMonitors[i].dragMotion;
if (motionFunc) {
let result = motionFunc(dragEvent);
if (result != DND.DragMotionResult.CONTINUE)
return;
}
}
while (pickedActor) {
if (pickedActor._delegate && pickedActor._delegate.handleDragOver) {
let [r_, targX, targY] = pickedActor.transform_stage_point(x, y);
let result = pickedActor._delegate.handleDragOver(this,
dragEvent.dragActor,
targX,
targY,
global.get_current_time());
if (result != DND.DragMotionResult.CONTINUE)
return;
}
pickedActor = pickedActor.get_parent();
}
}
};