summaryrefslogtreecommitdiff
path: root/Userland/Libraries/LibWeb/HTML/Window.cpp
blob: eb50c3514f9d5f9cbb0fafe7e515dc4be2109509 (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
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
/*
 * Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
 * Copyright (c) 2021-2022, Sam Atkins <atkinssj@serenityos.org>
 *
 * SPDX-License-Identifier: BSD-2-Clause
 */

#include <LibGUI/DisplayLink.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/FunctionObject.h>
#include <LibWeb/Bindings/IDLAbstractOperations.h>
#include <LibWeb/CSS/Parser/Parser.h>
#include <LibWeb/CSS/ResolvedCSSStyleDeclaration.h>
#include <LibWeb/Crypto/Crypto.h>
#include <LibWeb/DOM/Document.h>
#include <LibWeb/DOM/Event.h>
#include <LibWeb/DOM/EventDispatcher.h>
#include <LibWeb/HTML/BrowsingContext.h>
#include <LibWeb/HTML/EventLoop/EventLoop.h>
#include <LibWeb/HTML/MessageEvent.h>
#include <LibWeb/HTML/PageTransitionEvent.h>
#include <LibWeb/HTML/Scripting/ClassicScript.h>
#include <LibWeb/HTML/Scripting/ExceptionReporter.h>
#include <LibWeb/HTML/Storage.h>
#include <LibWeb/HTML/Timer.h>
#include <LibWeb/HTML/Window.h>
#include <LibWeb/HighResolutionTime/Performance.h>
#include <LibWeb/Layout/InitialContainingBlock.h>
#include <LibWeb/Page/Page.h>
#include <LibWeb/Selection/Selection.h>

namespace Web::HTML {

class RequestAnimationFrameCallback : public RefCounted<RequestAnimationFrameCallback> {
public:
    explicit RequestAnimationFrameCallback(i32 id, Function<void(i32)> handler)
        : m_id(id)
        , m_handler(move(handler))
    {
    }
    ~RequestAnimationFrameCallback() = default;

    i32 id() const { return m_id; }
    bool is_cancelled() const { return !m_handler; }

    void cancel() { m_handler = nullptr; }
    void invoke() { m_handler(m_id); }

private:
    i32 m_id { 0 };
    Function<void(i32)> m_handler;
};

struct RequestAnimationFrameDriver {
    RequestAnimationFrameDriver()
    {
        m_timer = Core::Timer::create_single_shot(16, [] {
            HTML::main_thread_event_loop().schedule();
        });
    }

    NonnullRefPtr<RequestAnimationFrameCallback> add(Function<void(i32)> handler)
    {
        auto id = m_id_allocator.allocate();
        auto callback = adopt_ref(*new RequestAnimationFrameCallback { id, move(handler) });
        m_callbacks.set(id, callback);
        if (!m_timer->is_active())
            m_timer->start();
        return callback;
    }

    bool remove(i32 id)
    {
        auto it = m_callbacks.find(id);
        if (it == m_callbacks.end())
            return false;
        m_callbacks.remove(it);
        m_id_allocator.deallocate(id);
        return true;
    }

    void run()
    {
        auto taken_callbacks = move(m_callbacks);
        for (auto& it : taken_callbacks) {
            if (!it.value->is_cancelled())
                it.value->invoke();
        }
    }

private:
    HashMap<i32, NonnullRefPtr<RequestAnimationFrameCallback>> m_callbacks;
    IDAllocator m_id_allocator;
    RefPtr<Core::Timer> m_timer;
};

static RequestAnimationFrameDriver& request_animation_frame_driver()
{
    static RequestAnimationFrameDriver driver;
    return driver;
}

// https://html.spec.whatwg.org/#run-the-animation-frame-callbacks
void run_animation_frame_callbacks(DOM::Document&, double)
{
    // FIXME: Bring this closer to the spec.
    request_animation_frame_driver().run();
}

NonnullRefPtr<Window> Window::create_with_document(DOM::Document& document)
{
    return adopt_ref(*new Window(document));
}

Window::Window(DOM::Document& document)
    : DOM::EventTarget()
    , m_associated_document(document)
    , m_performance(make<HighResolutionTime::Performance>(*this))
    , m_crypto(Crypto::Crypto::create())
    , m_screen(CSS::Screen::create({}, *this))
{
}

Window::~Window() = default;

void Window::set_wrapper(Badge<Bindings::WindowObject>, Bindings::WindowObject& wrapper)
{
    m_wrapper = wrapper.make_weak_ptr();
}

void Window::alert(String const& message)
{
    if (auto* page = this->page())
        page->client().page_did_request_alert(message);
}

bool Window::confirm(String const& message)
{
    if (auto* page = this->page())
        return page->client().page_did_request_confirm(message);
    return false;
}

String Window::prompt(String const& message, String const& default_)
{
    if (auto* page = this->page())
        return page->client().page_did_request_prompt(message, default_);
    return {};
}

// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-settimeout
i32 Window::set_timeout(Bindings::TimerHandler handler, i32 timeout, JS::MarkedVector<JS::Value> arguments)
{
    return run_timer_initialization_steps(move(handler), timeout, move(arguments), Repeat::No);
}

// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-setinterval
i32 Window::set_interval(Bindings::TimerHandler handler, i32 timeout, JS::MarkedVector<JS::Value> arguments)
{
    return run_timer_initialization_steps(move(handler), timeout, move(arguments), Repeat::Yes);
}

// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-cleartimeout
void Window::clear_timeout(i32 id)
{
    m_timers.remove(id);
}

// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#dom-clearinterval
void Window::clear_interval(i32 id)
{
    m_timers.remove(id);
}

void Window::deallocate_timer_id(Badge<Timer>, i32 id)
{
    m_timer_id_allocator.deallocate(id);
}

// https://html.spec.whatwg.org/multipage/timers-and-user-prompts.html#timer-initialisation-steps
i32 Window::run_timer_initialization_steps(Bindings::TimerHandler handler, i32 timeout, JS::MarkedVector<JS::Value> arguments, Repeat repeat, Optional<i32> previous_id)
{
    // 1. Let thisArg be global if that is a WorkerGlobalScope object; otherwise let thisArg be the WindowProxy that corresponds to global.

    // 2. If previousId was given, let id be previousId; otherwise, let id be an implementation-defined integer that is greater than zero and does not already exist in global's map of active timers.
    auto id = previous_id.has_value() ? previous_id.value() : m_timer_id_allocator.allocate();

    // 3. FIXME: If the surrounding agent's event loop's currently running task is a task that was created by this algorithm, then let nesting level be the task's timer nesting level. Otherwise, let nesting level be zero.

    // 4. If timeout is less than 0, then set timeout to 0.
    if (timeout < 0)
        timeout = 0;

    // 5. FIXME: If nesting level is greater than 5, and timeout is less than 4, then set timeout to 4.

    // 6. Let callerRealm be the current Realm Record, and calleeRealm be global's relevant Realm.
    // FIXME: Implement this when step 9.2 is implemented.

    // 7. Let initiating script be the active script.
    // 8. Assert: initiating script is not null, since this algorithm is always called from some script.

    // 9. Let task be a task that runs the following substeps:
    auto task = [weak_window = make_weak_ptr(), handler = move(handler), timeout, arguments = move(arguments), repeat, id]() mutable {
        auto window = weak_window.strong_ref();
        if (!window)
            return;

        // 1. If id does not exist in global's map of active timers, then abort these steps.
        if (!window->m_timers.contains(id))
            return;

        handler.visit(
            // 2. If handler is a Function, then invoke handler given arguments with the callback this value set to thisArg. If this throws an exception, catch it, and report the exception.
            [&](Bindings::CallbackType& callback) {
                if (auto result = Bindings::IDL::invoke_callback(callback, window->wrapper(), arguments); result.is_error())
                    HTML::report_exception(result);
            },
            // 3. Otherwise:
            [&](String const& source) {
                // 1. Assert: handler is a string.
                // 2. FIXME: Perform HostEnsureCanCompileStrings(callerRealm, calleeRealm). If this throws an exception, catch it, report the exception, and abort these steps.

                // 3. Let settings object be global's relevant settings object.
                auto& settings_object = window->associated_document().relevant_settings_object();

                // 4. Let base URL be initiating script's base URL.
                auto url = window->associated_document().url();

                // 5. Assert: base URL is not null, as initiating script is a classic script or a JavaScript module script.

                // 6. Let fetch options be a script fetch options whose cryptographic nonce is initiating script's fetch options's cryptographic nonce, integrity metadata is the empty string, parser metadata is "not-parser-inserted", credentials mode is initiating script's fetch options's credentials mode, and referrer policy is initiating script's fetch options's referrer policy.
                // 7. Let script be the result of creating a classic script given handler, settings object, base URL, and fetch options.
                auto script = HTML::ClassicScript::create(url.basename(), source, settings_object, url);

                // 8. Run the classic script script.
                (void)script->run();
            });

        // 4. If id does not exist in global's map of active timers, then abort these steps.
        if (!window->m_timers.contains(id))
            return;

        switch (repeat) {
        // 5. If repeat is true, then perform the timer initialization steps again, given global, handler, timeout, arguments, true, and id.
        case Repeat::Yes:
            window->run_timer_initialization_steps(handler, timeout, move(arguments), repeat, id);
            break;

        // 6. Otherwise, remove global's map of active timers[id].
        case Repeat::No:
            window->m_timers.remove(id);
            break;
        }
    };

    // 10. FIXME: Increment nesting level by one.
    // 11. FIXME: Set task's timer nesting level to nesting level.

    // 12. Let completionStep be an algorithm step which queues a global task on the timer task source given global to run task.
    auto completion_step = [weak_window = make_weak_ptr(), task = move(task)]() mutable {
        auto window = weak_window.strong_ref();
        if (!window)
            return;

        HTML::queue_global_task(HTML::Task::Source::TimerTask, *window->wrapper(), move(task));
    };

    // 13. Run steps after a timeout given global, "setTimeout/setInterval", timeout, completionStep, and id.
    auto timer = Timer::create(*this, timeout, move(completion_step), id);
    m_timers.set(id, timer);
    timer->start();

    // 14. Return id.
    return id;
}

// https://html.spec.whatwg.org/multipage/imagebitmap-and-animations.html#run-the-animation-frame-callbacks
i32 Window::request_animation_frame(NonnullOwnPtr<Bindings::CallbackType> js_callback)
{
    auto callback = request_animation_frame_driver().add([this, js_callback = move(js_callback)](i32 id) mutable {
        // 3. Invoke callback, passing now as the only argument,
        auto result = Bindings::IDL::invoke_callback(*js_callback, {}, JS::Value(performance().now()));

        // and if an exception is thrown, report the exception.
        if (result.is_error())
            HTML::report_exception(result);
        m_request_animation_frame_callbacks.remove(id);
    });
    m_request_animation_frame_callbacks.set(callback->id(), callback);
    return callback->id();
}

void Window::cancel_animation_frame(i32 id)
{
    auto it = m_request_animation_frame_callbacks.find(id);
    if (it == m_request_animation_frame_callbacks.end())
        return;
    it->value->cancel();
    m_request_animation_frame_callbacks.remove(it);
}

void Window::did_set_location_href(Badge<Bindings::LocationObject>, AK::URL const& new_href)
{
    auto* browsing_context = associated_document().browsing_context();
    if (!browsing_context)
        return;
    browsing_context->loader().load(new_href, FrameLoader::Type::Navigation);
}

void Window::did_call_location_reload(Badge<Bindings::LocationObject>)
{
    auto* browsing_context = associated_document().browsing_context();
    if (!browsing_context)
        return;
    browsing_context->loader().load(associated_document().url(), FrameLoader::Type::Reload);
}

void Window::did_call_location_replace(Badge<Bindings::LocationObject>, String url)
{
    auto* browsing_context = associated_document().browsing_context();
    if (!browsing_context)
        return;
    auto new_url = associated_document().parse_url(url);
    browsing_context->loader().load(move(new_url), FrameLoader::Type::Navigation);
}

bool Window::dispatch_event(NonnullRefPtr<DOM::Event> event)
{
    return DOM::EventDispatcher::dispatch(*this, event, true);
}

JS::Object* Window::create_wrapper(JS::GlobalObject& global_object)
{
    return &global_object;
}

// https://www.w3.org/TR/cssom-view-1/#dom-window-innerwidth
int Window::inner_width() const
{
    // The innerWidth attribute must return the viewport width including the size of a rendered scroll bar (if any),
    // or zero if there is no viewport.
    if (auto const* browsing_context = associated_document().browsing_context())
        return browsing_context->viewport_rect().width();
    return 0;
}

// https://www.w3.org/TR/cssom-view-1/#dom-window-innerheight
int Window::inner_height() const
{
    // The innerHeight attribute must return the viewport height including the size of a rendered scroll bar (if any),
    // or zero if there is no viewport.
    if (auto const* browsing_context = associated_document().browsing_context())
        return browsing_context->viewport_rect().height();
    return 0;
}

Page* Window::page()
{
    return associated_document().page();
}

Page const* Window::page() const
{
    return associated_document().page();
}

NonnullRefPtr<CSS::CSSStyleDeclaration> Window::get_computed_style(DOM::Element& element) const
{
    return CSS::ResolvedCSSStyleDeclaration::create(element);
}

NonnullRefPtr<CSS::MediaQueryList> Window::match_media(String media)
{
    auto media_query_list = CSS::MediaQueryList::create(associated_document(), parse_media_query_list(CSS::ParsingContext(associated_document()), media));
    associated_document().add_media_query_list(media_query_list);
    return media_query_list;
}

Optional<CSS::MediaFeatureValue> Window::query_media_feature(CSS::MediaFeatureID media_feature) const
{
    // FIXME: Many of these should be dependent on the hardware

    // https://www.w3.org/TR/mediaqueries-5/#media-descriptor-table
    switch (media_feature) {
    case CSS::MediaFeatureID::AnyHover:
        return CSS::MediaFeatureValue(CSS::ValueID::Hover);
    case CSS::MediaFeatureID::AnyPointer:
        return CSS::MediaFeatureValue(CSS::ValueID::Fine);
    case CSS::MediaFeatureID::AspectRatio:
        return CSS::MediaFeatureValue(CSS::Ratio(inner_width(), inner_height()));
    case CSS::MediaFeatureID::Color:
        return CSS::MediaFeatureValue(8);
    case CSS::MediaFeatureID::ColorGamut:
        return CSS::MediaFeatureValue(CSS::ValueID::Srgb);
    case CSS::MediaFeatureID::ColorIndex:
        return CSS::MediaFeatureValue(0);
    // FIXME: device-aspect-ratio
    // FIXME: device-height
    // FIXME: device-width
    case CSS::MediaFeatureID::DisplayMode:
        // FIXME: Detect if window is fullscreen
        return CSS::MediaFeatureValue(CSS::ValueID::Browser);
    case CSS::MediaFeatureID::DynamicRange:
        return CSS::MediaFeatureValue(CSS::ValueID::Standard);
    case CSS::MediaFeatureID::EnvironmentBlending:
        return CSS::MediaFeatureValue(CSS::ValueID::Opaque);
    case CSS::MediaFeatureID::ForcedColors:
        return CSS::MediaFeatureValue(CSS::ValueID::None);
    case CSS::MediaFeatureID::Grid:
        return CSS::MediaFeatureValue(0);
    case CSS::MediaFeatureID::Height:
        return CSS::MediaFeatureValue(CSS::Length::make_px(inner_height()));
    case CSS::MediaFeatureID::HorizontalViewportSegments:
        return CSS::MediaFeatureValue(1);
    case CSS::MediaFeatureID::Hover:
        return CSS::MediaFeatureValue(CSS::ValueID::Hover);
    case CSS::MediaFeatureID::InvertedColors:
        return CSS::MediaFeatureValue(CSS::ValueID::None);
    case CSS::MediaFeatureID::Monochrome:
        return CSS::MediaFeatureValue(0);
    case CSS::MediaFeatureID::NavControls:
        return CSS::MediaFeatureValue(CSS::ValueID::Back);
    case CSS::MediaFeatureID::Orientation:
        return CSS::MediaFeatureValue(inner_height() >= inner_width() ? CSS::ValueID::Portrait : CSS::ValueID::Landscape);
    case CSS::MediaFeatureID::OverflowBlock:
        return CSS::MediaFeatureValue(CSS::ValueID::Scroll);
    case CSS::MediaFeatureID::OverflowInline:
        return CSS::MediaFeatureValue(CSS::ValueID::Scroll);
    case CSS::MediaFeatureID::Pointer:
        return CSS::MediaFeatureValue(CSS::ValueID::Fine);
    case CSS::MediaFeatureID::PrefersColorScheme: {
        if (auto* page = this->page()) {
            switch (page->preferred_color_scheme()) {
            case CSS::PreferredColorScheme::Light:
                return CSS::MediaFeatureValue(CSS::ValueID::Light);
            case CSS::PreferredColorScheme::Dark:
                return CSS::MediaFeatureValue(CSS::ValueID::Dark);
            case CSS::PreferredColorScheme::Auto:
            default:
                return CSS::MediaFeatureValue(page->palette().is_dark() ? CSS::ValueID::Dark : CSS::ValueID::Light);
            }
        }
        return CSS::MediaFeatureValue(CSS::ValueID::Light);
    }
    case CSS::MediaFeatureID::PrefersContrast:
        // FIXME: Make this a preference
        return CSS::MediaFeatureValue(CSS::ValueID::NoPreference);
    case CSS::MediaFeatureID::PrefersReducedData:
        // FIXME: Make this a preference
        return CSS::MediaFeatureValue(CSS::ValueID::NoPreference);
    case CSS::MediaFeatureID::PrefersReducedMotion:
        // FIXME: Make this a preference
        return CSS::MediaFeatureValue(CSS::ValueID::NoPreference);
    case CSS::MediaFeatureID::PrefersReducedTransparency:
        // FIXME: Make this a preference
        return CSS::MediaFeatureValue(CSS::ValueID::NoPreference);
    // FIXME: resolution
    case CSS::MediaFeatureID::Scan:
        return CSS::MediaFeatureValue(CSS::ValueID::Progressive);
    case CSS::MediaFeatureID::Scripting:
        if (associated_document().is_scripting_enabled())
            return CSS::MediaFeatureValue(CSS::ValueID::Enabled);
        return CSS::MediaFeatureValue(CSS::ValueID::None);
    case CSS::MediaFeatureID::Update:
        return CSS::MediaFeatureValue(CSS::ValueID::Fast);
    case CSS::MediaFeatureID::VerticalViewportSegments:
        return CSS::MediaFeatureValue(1);
    case CSS::MediaFeatureID::VideoColorGamut:
        return CSS::MediaFeatureValue(CSS::ValueID::Srgb);
    case CSS::MediaFeatureID::VideoDynamicRange:
        return CSS::MediaFeatureValue(CSS::ValueID::Standard);
    case CSS::MediaFeatureID::Width:
        return CSS::MediaFeatureValue(CSS::Length::make_px(inner_width()));

    default:
        break;
    }

    return {};
}

// https://www.w3.org/TR/cssom-view/#dom-window-scrollx
float Window::scroll_x() const
{
    if (auto* page = this->page())
        return page->top_level_browsing_context().viewport_scroll_offset().x();
    return 0;
}

// https://www.w3.org/TR/cssom-view/#dom-window-scrolly
float Window::scroll_y() const
{
    if (auto* page = this->page())
        return page->top_level_browsing_context().viewport_scroll_offset().y();
    return 0;
}

// https://html.spec.whatwg.org/#fire-a-page-transition-event
void Window::fire_a_page_transition_event(FlyString const& event_name, bool persisted)
{
    // To fire a page transition event named eventName at a Window window with a boolean persisted,
    // fire an event named eventName at window, using PageTransitionEvent,
    // with the persisted attribute initialized to persisted,
    HTML::PageTransitionEventInit event_init {};
    event_init.persisted = persisted;
    auto event = HTML::PageTransitionEvent::create(event_name, event_init);

    // ...the cancelable attribute initialized to true,
    event->set_cancelable(true);

    // the bubbles attribute initialized to true,
    event->set_bubbles(true);

    // and legacy target override flag set.
    dispatch_event(move(event));
}

// https://html.spec.whatwg.org/#dom-queuemicrotask
void Window::queue_microtask(NonnullOwnPtr<Bindings::CallbackType> callback)
{
    // The queueMicrotask(callback) method must queue a microtask to invoke callback,
    HTML::queue_a_microtask(&associated_document(), [callback = move(callback)]() mutable {
        auto result = Bindings::IDL::invoke_callback(*callback, {});
        // and if callback throws an exception, report the exception.
        if (result.is_error())
            HTML::report_exception(result);
    });
}

float Window::device_pixel_ratio() const
{
    // FIXME: Return 2.0f if we're in HiDPI mode!
    return 1.0f;
}

// https://drafts.csswg.org/cssom-view/#dom-window-screenx
int Window::screen_x() const
{
    // The screenX and screenLeft attributes must return the x-coordinate, relative to the origin of the Web-exposed screen area,
    // of the left of the client window as number of CSS pixels, or zero if there is no such thing.
    return 0;
}

// https://drafts.csswg.org/cssom-view/#dom-window-screeny
int Window::screen_y() const
{
    // The screenY and screenTop attributes must return the y-coordinate, relative to the origin of the screen of the Web-exposed screen area,
    // of the top of the client window as number of CSS pixels, or zero if there is no such thing.
    return 0;
}

// https://w3c.github.io/selection-api/#dom-window-getselection
Selection::Selection* Window::get_selection()
{
    // FIXME: Implement.
    return nullptr;
}

// https://html.spec.whatwg.org/multipage/webstorage.html#dom-localstorage
RefPtr<HTML::Storage> Window::local_storage()
{
    // FIXME: Implement according to spec.

    static HashMap<Origin, NonnullRefPtr<HTML::Storage>> local_storage_per_origin;
    return local_storage_per_origin.ensure(associated_document().origin(), [] {
        return HTML::Storage::create();
    });
}

// https://html.spec.whatwg.org/multipage/webstorage.html#dom-sessionstorage
RefPtr<HTML::Storage> Window::session_storage()
{
    // FIXME: Implement according to spec.

    static HashMap<Origin, NonnullRefPtr<HTML::Storage>> session_storage_per_origin;
    return session_storage_per_origin.ensure(associated_document().origin(), [] {
        return HTML::Storage::create();
    });
}

// https://html.spec.whatwg.org/multipage/browsers.html#dom-parent
Window* Window::parent()
{
    // 1. Let current be this Window object's browsing context.
    auto* current = associated_document().browsing_context();

    // 2. If current is null, then return null.
    if (!current)
        return nullptr;

    // 3. If current is a child browsing context of another browsing context parent,
    //    then return parent's WindowProxy object.
    if (current->parent()) {
        VERIFY(current->parent()->active_document());
        return &current->parent()->active_document()->window();
    }

    // 4. Assert: current is a top-level browsing context.
    VERIFY(current->is_top_level());

    // FIXME: 5. Return current's WindowProxy object.
    VERIFY(current->active_document());
    return &current->active_document()->window();
}

// https://html.spec.whatwg.org/multipage/web-messaging.html#window-post-message-steps
DOM::ExceptionOr<void> Window::post_message(JS::Value message, String const&)
{
    // FIXME: This is an ad-hoc hack implementation instead, since we don't currently
    //        have serialization and deserialization of messages.
    HTML::queue_global_task(HTML::Task::Source::PostedMessage, *wrapper(), [strong_this = NonnullRefPtr(*this), message]() mutable {
        HTML::MessageEventInit event_init {};
        event_init.data = message;
        event_init.origin = "<origin>";
        strong_this->dispatch_event(HTML::MessageEvent::create(HTML::EventNames::message, event_init));
    });
    return {};
}

// https://html.spec.whatwg.org/multipage/window-object.html#dom-name
String Window::name() const
{
    // 1. If this's browsing context is null, then return the empty string.
    if (!browsing_context())
        return String::empty();
    // 2. Return this's browsing context's name.
    return browsing_context()->name();
}

// https://html.spec.whatwg.org/multipage/window-object.html#dom-name
void Window::set_name(String const& name)
{
    // 1. If this's browsing context is null, then return.
    if (!browsing_context())
        return;
    // 2. Set this's browsing context's name to the given value.
    browsing_context()->set_name(name);
}

}