summaryrefslogtreecommitdiffstats
path: root/js/ui/grabHelper.js
blob: 2ba2aad9a3295d987ccaa3b3132e189f517b1b13 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
/* exported GrabHelper */

const { Clutter, St } = imports.gi;

const Main = imports.ui.main;
const Params = imports.misc.params;

let _capturedEventId = 0;
let _grabHelperStack = [];
function _onCapturedEvent(actor, event) {
    let grabHelper = _grabHelperStack[_grabHelperStack.length - 1];
    return grabHelper.onCapturedEvent(event);
}

function _pushGrabHelper(grabHelper) {
    _grabHelperStack.push(grabHelper);

    if (_capturedEventId == 0)
        _capturedEventId = global.stage.connect('captured-event', _onCapturedEvent);
}

function _popGrabHelper(grabHelper) {
    let poppedHelper = _grabHelperStack.pop();
    if (poppedHelper != grabHelper)
        throw new Error("incorrect grab helper pop");

    if (_grabHelperStack.length == 0) {
        global.stage.disconnect(_capturedEventId);
        _capturedEventId = 0;
    }
}

// GrabHelper:
// @owner: the actor that owns the GrabHelper
// @params: optional parameters to pass to Main.pushModal()
//
// Creates a new GrabHelper object, for dealing with keyboard and pointer grabs
// associated with a set of actors.
//
// Note that the grab can be automatically dropped at any time by the user, and
// your code just needs to deal with it; you shouldn't adjust behavior directly
// after you call ungrab(), but instead pass an 'onUngrab' callback when you
// call grab().
var GrabHelper = class GrabHelper {
    constructor(owner, params) {
        if (!(owner instanceof Clutter.Actor))
            throw new Error('GrabHelper owner must be a Clutter.Actor');

        this._owner = owner;
        this._modalParams = params;

        this._grabStack = [];

        this._actors = [];
        this._ignoreUntilRelease = false;

        this._modalCount = 0;
    }

    // addActor:
    // @actor: an actor
    //
    // Adds @actor to the set of actors that are allowed to process events
    // during a grab.
    addActor(actor) {
        actor.__grabHelperDestroyId = actor.connect('destroy', () => {
            this.removeActor(actor);
        });
        this._actors.push(actor);
    }

    // removeActor:
    // @actor: an actor
    //
    // Removes @actor from the set of actors that are allowed to
    // process events during a grab.
    removeActor(actor) {
        let index = this._actors.indexOf(actor);
        if (index != -1)
            this._actors.splice(index, 1);
        if (actor.__grabHelperDestroyId) {
            actor.disconnect(actor.__grabHelperDestroyId);
            delete actor.__grabHelperDestroyId;
        }
    }

    _isWithinGrabbedActor(actor) {
        let currentActor = this.currentGrab.actor;
        while (actor) {
            if (this._actors.includes(actor))
                return true;
            if (actor == currentActor)
                return true;
            actor = actor.get_parent();
        }
        return false;
    }

    get currentGrab() {
        return this._grabStack[this._grabStack.length - 1] || {};
    }

    get grabbed() {
        return this._grabStack.length > 0;
    }

    get grabStack() {
        return this._grabStack;
    }

    _findStackIndex(actor) {
        if (!actor)
            return -1;

        for (let i = 0; i < this._grabStack.length; i++) {
            if (this._grabStack[i].actor === actor)
                return i;
        }
        return -1;
    }

    _actorInGrabStack(actor) {
        while (actor) {
            let idx = this._findStackIndex(actor);
            if (idx >= 0)
                return idx;
            actor = actor.get_parent();
        }
        return -1;
    }

    isActorGrabbed(actor) {
        return this._findStackIndex(actor) >= 0;
    }

    // grab:
    // @params: A bunch of parameters, see below
    //
    // The general effect of a "grab" is to ensure that the passed in actor
    // and all actors inside the grab get exclusive control of the mouse and
    // keyboard, with the grab automatically being dropped if the user tries
    // to dismiss it. The actor is passed in through @params.actor.
    //
    // grab() can be called multiple times, with the scope of the grab being
    // changed to a different actor every time. A nested grab does not have
    // to have its grabbed actor inside the parent grab actors.
    //
    // Grabs can be automatically dropped if the user tries to dismiss it
    // in one of two ways: the user clicking outside the currently grabbed
    // actor, or the user typing the Escape key.
    //
    // If the user clicks outside the grabbed actors, and the clicked on
    // actor is part of a previous grab in the stack, grabs will be popped
    // until that grab is active. However, the click event will not be
    // replayed to the actor.
    //
    // If the user types the Escape key, one grab from the grab stack will
    // be popped.
    //
    // When a grab is popped by user interacting as described above, if you
    // pass a callback as @params.onUngrab, it will be called with %true.
    //
    // If @params.focus is not null, we'll set the key focus directly
    // to that actor instead of navigating in @params.actor. This is for
    // use cases like menus, where we want to grab the menu actor, but keep
    // focus on the clicked on menu item.
    grab(params) {
        params = Params.parse(params, { actor: null,
                                        focus: null,
                                        onUngrab: null });

        let focus = global.stage.key_focus;
        let hadFocus = focus && this._isWithinGrabbedActor(focus);
        let newFocus = params.actor;

        if (this.isActorGrabbed(params.actor))
            return true;

        params.savedFocus = focus;

        if (!this._takeModalGrab())
            return false;

        this._grabStack.push(params);

        if (params.focus) {
            params.focus.grab_key_focus();
        } else if (newFocus && hadFocus) {
            if (!newFocus.navigate_focus(null, St.DirectionType.TAB_FORWARD, false))
                newFocus.grab_key_focus();
        }

        return true;
    }

    grabAsync(params) {
        return new Promise((resolve, reject) => {
            params.onUngrab = resolve;

            if (!this.grab(params))
                reject(new Error('Grab failed'));
        });
    }

    _takeModalGrab() {
        let firstGrab = this._modalCount == 0;
        if (firstGrab) {
            if (!Main.pushModal(this._owner, this._modalParams))
                return false;

            _pushGrabHelper(this);
        }

        this._modalCount++;
        return true;
    }

    _releaseModalGrab() {
        this._modalCount--;
        if (this._modalCount > 0)
            return;

        _popGrabHelper(this);

        this._ignoreUntilRelease = false;

        Main.popModal(this._owner);
        global.sync_pointer();
    }

    // ignoreRelease:
    //
    // Make sure that the next button release event evaluated by the
    // capture event handler returns false. This is designed for things
    // like the ComboBoxMenu that go away on press, but need to eat
    // the next release event.
    ignoreRelease() {
        this._ignoreUntilRelease = true;
    }

    // ungrab:
    // @params: The parameters for the grab; see below.
    //
    // Pops @params.actor from the grab stack, potentially dropping
    // the grab. If the actor is not on the grab stack, this call is
    // ignored with no ill effects.
    //
    // If the actor is not at the top of the grab stack, grabs are
    // popped until the grabbed actor is at the top of the grab stack.
    // The onUngrab callback for every grab is called for every popped
    // grab with the parameter %false.
    ungrab(params) {
        params = Params.parse(params, { actor: this.currentGrab.actor,
                                        isUser: false });

        let grabStackIndex = this._findStackIndex(params.actor);
        if (grabStackIndex < 0)
            return;

        let focus = global.stage.key_focus;
        let hadFocus = focus && this._isWithinGrabbedActor(focus);

        let poppedGrabs = this._grabStack.slice(grabStackIndex);
        // "Pop" all newly ungrabbed actors off the grab stack
        // by truncating the array.
        this._grabStack.length = grabStackIndex;

        for (let i = poppedGrabs.length - 1; i >= 0; i--) {
            let poppedGrab = poppedGrabs[i];

            if (poppedGrab.onUngrab)
                poppedGrab.onUngrab(params.isUser);

            this._releaseModalGrab();
        }

        if (hadFocus) {
            let poppedGrab = poppedGrabs[0];
            if (poppedGrab.savedFocus)
                poppedGrab.savedFocus.grab_key_focus();
        }
    }

    onCapturedEvent(event) {
        let type = event.type();

        if (type == Clutter.EventType.KEY_PRESS &&
            event.get_key_symbol() == Clutter.KEY_Escape) {
            this.ungrab({ isUser: true });
            return Clutter.EVENT_STOP;
        }

        let motion = type == Clutter.EventType.MOTION;
        let press = type == Clutter.EventType.BUTTON_PRESS;
        let release = type == Clutter.EventType.BUTTON_RELEASE;
        let button = press || release;

        let touchUpdate = type == Clutter.EventType.TOUCH_UPDATE;
        let touchBegin = type == Clutter.EventType.TOUCH_BEGIN;
        let touchEnd = type == Clutter.EventType.TOUCH_END;
        let touch = touchUpdate || touchBegin || touchEnd;

        if (touch && !global.display.is_pointer_emulating_sequence(event.get_event_sequence()))
            return Clutter.EVENT_PROPAGATE;

        if (this._ignoreUntilRelease && (motion || release || touch)) {
            if (release || touchEnd)
                this._ignoreUntilRelease = false;
            return Clutter.EVENT_STOP;
        }

        if (this._isWithinGrabbedActor(event.get_source()))
            return Clutter.EVENT_PROPAGATE;

        if (Main.keyboard.shouldTakeEvent(event))
            return Clutter.EVENT_PROPAGATE;

        if (button || touchBegin) {
            // If we have a press event, ignore the next
            // motion/release events.
            if (press || touchBegin)
                this._ignoreUntilRelease = true;

            let i = this._actorInGrabStack(event.get_source()) + 1;
            this.ungrab({ actor: this._grabStack[i].actor, isUser: true });
            return Clutter.EVENT_STOP;
        }

        return Clutter.EVENT_STOP;
    }
};