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
641
642
643
644
645
646
647
648
649
650
651
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

//! The implementation of the DOM.
//!
//! The DOM is comprised of interfaces (defined by specifications using
//! [WebIDL](https://heycam.github.io/webidl/)) that are implemented as Rust
//! structs in submodules of this module. Its implementation is documented
//! below.
//!
//! A DOM object and its reflector
//! ==============================
//!
//! The implementation of an interface `Foo` in Servo's DOM involves two
//! related but distinct objects:
//!
//! * the **DOM object**: an instance of the Rust struct `dom::foo::Foo`
//!   (marked with the `#[dom_struct]` attribute) on the Rust heap;
//! * the **reflector**: a `JSObject` allocated by SpiderMonkey, that owns the
//!   DOM object.
//!
//! Memory management
//! =================
//!
//! Reflectors of DOM objects, and thus the DOM objects themselves, are managed
//! by the SpiderMonkey Garbage Collector. Thus, keeping alive a DOM object
//! is done through its reflector.
//!
//! For more information, see:
//!
//! * rooting pointers on the stack:
//!   the [`Root`](bindings/root/struct.Root.html) smart pointer;
//! * tracing pointers in member fields: the [`Dom`](bindings/root/struct.Dom.html),
//!   [`MutNullableDom`](bindings/root/struct.MutNullableDom.html) and
//!   [`MutDom`](bindings/root/struct.MutDom.html) smart pointers and
//!   [the tracing implementation](bindings/trace/index.html);
//! * rooting pointers from across thread boundaries or in channels: the
//!   [`Trusted`](bindings/refcounted/struct.Trusted.html) smart pointer;
//!
//! Inheritance
//! ===========
//!
//! Rust does not support struct inheritance, as would be used for the
//! object-oriented DOM APIs. To work around this issue, Servo stores an
//! instance of the superclass in the first field of its subclasses. (Note that
//! it is stored by value, rather than in a smart pointer such as `Dom<T>`.)
//!
//! This implies that a pointer to an object can safely be cast to a pointer
//! to all its classes.
//!
//! This invariant is enforced by the lint in
//! `plugins::lints::inheritance_integrity`.
//!
//! Interfaces which either derive from or are derived by other interfaces
//! implement the `Castable` trait, which provides three methods `is::<T>()`,
//! `downcast::<T>()` and `upcast::<T>()` to cast across the type hierarchy
//! and check whether a given instance is of a given type.
//!
//! ```ignore
//! use dom::bindings::inheritance::Castable;
//! use dom::element::Element;
//! use dom::htmlelement::HTMLElement;
//! use dom::htmlinputelement::HTMLInputElement;
//!
//! if let Some(elem) = node.downcast::<Element> {
//!     if elem.is::<HTMLInputElement>() {
//!         return elem.upcast::<HTMLElement>();
//!     }
//! }
//! ```
//!
//! Furthermore, when discriminating a given instance against multiple
//! interface types, code generation provides a convenient TypeId enum
//! which can be used to write `match` expressions instead of multiple
//! calls to `Castable::is::<T>`. The `type_id()` method of an instance is
//! provided by the farthest interface it derives from, e.g. `EventTarget`
//! for `HTMLMediaElement`. For convenience, that method is also provided
//! on the `Node` interface to avoid unnecessary upcasts to `EventTarget`.
//!
//! ```ignore
//! use dom::bindings::inheritance::{EventTargetTypeId, NodeTypeId};
//!
//! match *node.type_id() {
//!     EventTargetTypeId::Node(NodeTypeId::CharacterData(_)) => ...,
//!     EventTargetTypeId::Node(NodeTypeId::Element(_)) => ...,
//!     ...,
//! }
//! ```
//!
//! Construction
//! ============
//!
//! DOM objects of type `T` in Servo have two constructors:
//!
//! * a `T::new_inherited` static method that returns a plain `T`, and
//! * a `T::new` static method that returns `DomRoot<T>`.
//!
//! (The result of either method can be wrapped in `Result`, if that is
//! appropriate for the type in question.)
//!
//! The latter calls the former, boxes the result, and creates a reflector
//! corresponding to it by calling `dom::bindings::utils::reflect_dom_object`
//! (which yields ownership of the object to the SpiderMonkey Garbage Collector).
//! This is the API to use when creating a DOM object.
//!
//! The former should only be called by the latter, and by subclasses'
//! `new_inherited` methods.
//!
//! DOM object constructors in JavaScript correspond to a `T::Constructor`
//! static method. This method is always fallible.
//!
//! Destruction
//! ===========
//!
//! When the SpiderMonkey Garbage Collector discovers that the reflector of a
//! DOM object is garbage, it calls the reflector's finalization hook. This
//! function deletes the reflector's DOM object, calling its destructor in the
//! process.
//!
//! Mutability and aliasing
//! =======================
//!
//! Reflectors are JavaScript objects, and as such can be freely aliased. As
//! Rust does not allow mutable aliasing, mutable borrows of DOM objects are
//! not allowed. In particular, any mutable fields use `Cell` or `DomRefCell`
//! to manage their mutability.
//!
//! `Reflector` and `DomObject`
//! =============================
//!
//! Every DOM object has a `Reflector` as its first (transitive) member field.
//! This contains a `*mut JSObject` that points to its reflector.
//!
//! The `FooBinding::Wrap` function creates the reflector, stores a pointer to
//! the DOM object in the reflector, and initializes the pointer to the reflector
//! in the `Reflector` field.
//!
//! The `DomObject` trait provides a `reflector()` method that returns the
//! DOM object's `Reflector`. It is implemented automatically for DOM structs
//! through the `#[dom_struct]` attribute.
//!
//! Implementing methods for a DOM object
//! =====================================
//!
//! * `dom::bindings::codegen::Bindings::FooBindings::FooMethods` for methods
//!   defined through IDL;
//! * `&self` public methods for public helpers;
//! * `&self` methods for private helpers.
//!
//! Accessing fields of a DOM object
//! ================================
//!
//! All fields of DOM objects are private; accessing them from outside their
//! module is done through explicit getter or setter methods.
//!
//! Inheritance and casting
//! =======================
//!
//! All DOM interfaces part of an inheritance chain (i.e. interfaces
//! that derive others or are derived from) implement the trait `Castable`
//! which provides both downcast and upcasts.
//!
//! ```ignore
//! # use script::dom::bindings::inheritance::Castable;
//! # use script::dom::element::Element;
//! # use script::dom::node::Node;
//! # use script::dom::htmlelement::HTMLElement;
//! fn f(element: &Element) {
//!     let base = element.upcast::<Node>();
//!     let derived = element.downcast::<HTMLElement>().unwrap();
//! }
//! ```
//!
//! Adding a new DOM interface
//! ==========================
//!
//! Adding a new interface `Foo` requires at least the following:
//!
//! * adding the new IDL file at `components/script/dom/webidls/Foo.webidl`;
//! * creating `components/script/dom/foo.rs`;
//! * listing `foo.rs` in `components/script/dom/mod.rs`;
//! * defining the DOM struct `Foo` with a `#[dom_struct]` attribute, a
//!   superclass or `Reflector` member, and other members as appropriate;
//! * implementing the
//!   `dom::bindings::codegen::Bindings::FooBindings::FooMethods` trait for
//!   `Foo`;
//! * adding/updating the match arm in create_element in
//!   `components/script/dom/create.rs` (only applicable to new types inheriting
//!   from `HTMLElement`)
//!
//! More information is available in the [bindings module](bindings/index.html).
//!
//! Accessing DOM objects from layout
//! =================================
//!
//! Layout code can access the DOM through the
//! [`LayoutDom`](bindings/root/struct.LayoutDom.html) smart pointer. This does not
//! keep the DOM object alive; we ensure that no DOM code (Garbage Collection
//! in particular) runs while layout is accessing the DOM.
//!
//! Methods accessible to layout are implemented on `LayoutDom<Foo>` using
//! `LayoutFooHelpers` traits.

#[macro_use]
pub mod macros;

pub mod types {
    include!(concat!(env!("OUT_DIR"), "/InterfaceTypes.rs"));
}

pub mod abstractrange;
pub mod abstractworker;
pub mod abstractworkerglobalscope;
pub mod activation;
pub mod analysernode;
pub mod animationevent;
pub mod attr;
pub mod audiobuffer;
pub mod audiobuffersourcenode;
pub mod audiocontext;
pub mod audiodestinationnode;
pub mod audiolistener;
pub mod audionode;
pub mod audioparam;
pub mod audioscheduledsourcenode;
pub mod audiotrack;
pub mod audiotracklist;
pub mod baseaudiocontext;
pub mod beforeunloadevent;
pub mod bindings;
pub mod biquadfilternode;
pub mod blob;
pub mod bluetooth;
pub mod bluetoothadvertisingevent;
pub mod bluetoothcharacteristicproperties;
pub mod bluetoothdevice;
pub mod bluetoothpermissionresult;
pub mod bluetoothremotegattcharacteristic;
pub mod bluetoothremotegattdescriptor;
pub mod bluetoothremotegattserver;
pub mod bluetoothremotegattservice;
pub mod bluetoothuuid;
pub mod broadcastchannel;
pub mod canvasgradient;
pub mod canvaspattern;
pub mod canvasrenderingcontext2d;
pub mod cdatasection;
pub mod channelmergernode;
pub mod channelsplitternode;
pub mod characterdata;
pub mod client;
pub mod closeevent;
pub mod comment;
pub mod compositionevent;
pub mod console;
pub mod constantsourcenode;
mod create;
pub mod crypto;
pub mod css;
pub mod cssconditionrule;
pub mod cssfontfacerule;
pub mod cssgroupingrule;
pub mod cssimportrule;
pub mod csskeyframerule;
pub mod csskeyframesrule;
pub mod csslayerblockrule;
pub mod csslayerstatementrule;
pub mod cssmediarule;
pub mod cssnamespacerule;
pub mod cssrule;
pub mod cssrulelist;
pub mod cssstyledeclaration;
pub mod cssstylerule;
pub mod cssstylesheet;
pub mod cssstylevalue;
pub mod csssupportsrule;
pub mod customelementregistry;
pub mod customevent;
pub mod dedicatedworkerglobalscope;
pub mod dissimilaroriginlocation;
pub mod dissimilaroriginwindow;
pub mod document;
pub mod documentfragment;
pub mod documentorshadowroot;
pub mod documenttype;
pub mod domexception;
pub mod domimplementation;
pub mod dommatrix;
pub mod dommatrixreadonly;
pub mod domparser;
pub mod dompoint;
pub mod dompointreadonly;
pub mod domquad;
pub mod domrect;
pub mod domrectreadonly;
pub mod domstringlist;
pub mod domstringmap;
pub mod domtokenlist;
pub mod dynamicmoduleowner;
pub mod element;
pub mod elementinternals;
pub mod errorevent;
pub mod event;
pub mod eventsource;
pub mod eventtarget;
pub mod extendableevent;
pub mod extendablemessageevent;
pub mod fakexrdevice;
pub mod fakexrinputcontroller;
pub mod file;
pub mod filelist;
pub mod filereader;
pub mod filereadersync;
pub mod focusevent;
pub mod formdata;
pub mod formdataevent;
pub mod gainnode;
pub mod gamepad;
pub mod gamepadbutton;
pub mod gamepadbuttonlist;
pub mod gamepadevent;
pub mod gamepadpose;
pub mod globalscope;
pub mod gpu;
pub mod gpuadapter;
pub mod gpuadapterinfo;
pub mod gpubindgroup;
pub mod gpubindgrouplayout;
pub mod gpubuffer;
pub mod gpubufferusage;
pub mod gpucanvascontext;
pub mod gpucolorwrite;
pub mod gpucommandbuffer;
pub mod gpucommandencoder;
pub mod gpucompilationinfo;
pub mod gpucompilationmessage;
pub mod gpucomputepassencoder;
pub mod gpucomputepipeline;
pub mod gpuconvert;
pub mod gpudevice;
pub mod gpudevicelostinfo;
pub mod gpumapmode;
pub mod gpuoutofmemoryerror;
pub mod gpupipelinelayout;
pub mod gpuqueryset;
pub mod gpuqueue;
pub mod gpurenderbundle;
pub mod gpurenderbundleencoder;
pub mod gpurenderpassencoder;
pub mod gpurenderpipeline;
pub mod gpusampler;
pub mod gpushadermodule;
pub mod gpushaderstage;
pub mod gpusupportedfeatures;
pub mod gpusupportedlimits;
pub mod gputexture;
pub mod gputextureusage;
pub mod gputextureview;
pub mod gpuuncapturederrorevent;
pub mod gpuvalidationerror;
pub mod hashchangeevent;
pub mod headers;
pub mod history;
pub mod htmlanchorelement;
pub mod htmlareaelement;
pub mod htmlaudioelement;
pub mod htmlbaseelement;
pub mod htmlbodyelement;
pub mod htmlbrelement;
pub mod htmlbuttonelement;
pub mod htmlcanvaselement;
pub mod htmlcollection;
pub mod htmldataelement;
pub mod htmldatalistelement;
pub mod htmldetailselement;
pub mod htmldialogelement;
pub mod htmldirectoryelement;
pub mod htmldivelement;
pub mod htmldlistelement;
pub mod htmlelement;
pub mod htmlembedelement;
pub mod htmlfieldsetelement;
pub mod htmlfontelement;
pub mod htmlformcontrolscollection;
pub mod htmlformelement;
pub mod htmlframeelement;
pub mod htmlframesetelement;
pub mod htmlheadelement;
pub mod htmlheadingelement;
pub mod htmlhrelement;
pub mod htmlhtmlelement;
pub mod htmliframeelement;
pub mod htmlimageelement;
pub mod htmlinputelement;
pub mod htmllabelelement;
pub mod htmllegendelement;
pub mod htmllielement;
pub mod htmllinkelement;
pub mod htmlmapelement;
pub mod htmlmediaelement;
pub mod htmlmenuelement;
pub mod htmlmetaelement;
pub mod htmlmeterelement;
pub mod htmlmodelement;
pub mod htmlobjectelement;
pub mod htmlolistelement;
pub mod htmloptgroupelement;
pub mod htmloptionelement;
pub mod htmloptionscollection;
pub mod htmloutputelement;
pub mod htmlparagraphelement;
pub mod htmlparamelement;
pub mod htmlpictureelement;
pub mod htmlpreelement;
pub mod htmlprogresselement;
pub mod htmlquoteelement;
pub mod htmlscriptelement;
pub mod htmlselectelement;
pub mod htmlsourceelement;
pub mod htmlspanelement;
pub mod htmlstyleelement;
pub mod htmltablecaptionelement;
pub mod htmltablecellelement;
pub mod htmltablecolelement;
pub mod htmltableelement;
pub mod htmltablerowelement;
pub mod htmltablesectionelement;
pub mod htmltemplateelement;
pub mod htmltextareaelement;
pub mod htmltimeelement;
pub mod htmltitleelement;
pub mod htmltrackelement;
pub mod htmlulistelement;
pub mod htmlunknownelement;
pub mod htmlvideoelement;
pub mod identityhub;
pub mod imagebitmap;
pub mod imagedata;
pub mod inputevent;
pub mod keyboardevent;
pub mod location;
pub mod mediadeviceinfo;
pub mod mediadevices;
pub mod mediaelementaudiosourcenode;
pub mod mediaerror;
pub mod mediafragmentparser;
pub mod medialist;
pub mod mediametadata;
pub mod mediaquerylist;
pub mod mediaquerylistevent;
pub mod mediasession;
pub mod mediastream;
pub mod mediastreamaudiodestinationnode;
pub mod mediastreamaudiosourcenode;
pub mod mediastreamtrack;
pub mod mediastreamtrackaudiosourcenode;
pub mod messagechannel;
pub mod messageevent;
pub mod messageport;
pub mod mimetype;
pub mod mimetypearray;
pub mod mouseevent;
pub mod mutationobserver;
pub mod mutationrecord;
pub mod namednodemap;
pub mod navigationpreloadmanager;
pub mod navigator;
pub mod navigatorinfo;
pub mod node;
pub mod nodeiterator;
pub mod nodelist;
pub mod offlineaudiocompletionevent;
pub mod offlineaudiocontext;
pub mod offscreencanvas;
pub mod offscreencanvasrenderingcontext2d;
pub mod oscillatornode;
pub mod pagetransitionevent;
pub mod paintrenderingcontext2d;
pub mod paintsize;
pub mod paintworkletglobalscope;
pub mod pannernode;
pub mod performance;
pub mod performanceentry;
pub mod performancemark;
pub mod performancemeasure;
pub mod performancenavigation;
pub mod performancenavigationtiming;
pub mod performanceobserver;
pub mod performanceobserverentrylist;
pub mod performancepainttiming;
pub mod performanceresourcetiming;
pub mod permissions;
pub mod permissionstatus;
pub mod plugin;
pub mod pluginarray;
pub mod popstateevent;
pub mod processinginstruction;
pub mod progressevent;
pub mod promise;
pub mod promisenativehandler;
pub mod promiserejectionevent;
pub mod radionodelist;
pub mod range;
pub mod raredata;
pub mod readablestream;
pub mod request;
pub mod response;
pub mod rtcdatachannel;
pub mod rtcdatachannelevent;
pub mod rtcerror;
pub mod rtcerrorevent;
pub mod rtcicecandidate;
pub mod rtcpeerconnection;
pub mod rtcpeerconnectioniceevent;
pub(crate) mod rtcrtpsender;
pub(crate) mod rtcrtptransceiver;
pub mod rtcsessiondescription;
pub mod rtctrackevent;
pub mod screen;
pub mod selection;
pub mod serviceworker;
pub mod serviceworkercontainer;
pub mod serviceworkerglobalscope;
pub mod serviceworkerregistration;
pub mod servoparser;
pub mod shadowroot;
pub mod staticrange;
pub mod stereopannernode;
pub mod storage;
pub mod storageevent;
pub mod stylepropertymapreadonly;
pub mod stylesheet;
pub mod stylesheetlist;
pub mod submitevent;
pub mod svgelement;
pub mod svggraphicselement;
pub mod svgsvgelement;
pub mod testbinding;
pub mod testbindingiterable;
pub mod testbindingmaplike;
pub mod testbindingpairiterable;
pub mod testbindingproxy;
pub mod testbindingsetlike;
pub mod testns;
pub mod testrunner;
pub mod testworklet;
pub mod testworkletglobalscope;
pub mod text;
pub mod textcontrol;
pub mod textdecoder;
pub mod textencoder;
pub mod textmetrics;
pub mod texttrack;
pub mod texttrackcue;
pub mod texttrackcuelist;
pub mod texttracklist;
pub mod timeranges;
pub mod touch;
pub mod touchevent;
pub mod touchlist;
pub mod trackevent;
pub mod transitionevent;
pub mod treewalker;
pub mod uievent;
pub mod url;
pub mod urlhelper;
pub mod urlsearchparams;
pub mod userscripts;
pub mod validation;
pub mod validitystate;
pub mod values;
pub mod vertexarrayobject;
pub mod videotrack;
pub mod videotracklist;
pub mod virtualmethods;
pub mod vttcue;
pub mod vttregion;
pub mod webgl2renderingcontext;
pub mod webgl_extensions;
pub mod webgl_validations;
pub mod webglactiveinfo;
pub mod webglbuffer;
pub mod webglcontextevent;
pub mod webglframebuffer;
pub mod webglobject;
pub mod webglprogram;
pub mod webglquery;
pub mod webglrenderbuffer;
pub mod webglrenderingcontext;
pub mod webglsampler;
pub mod webglshader;
pub mod webglshaderprecisionformat;
pub mod webglsync;
pub mod webgltexture;
pub mod webgltransformfeedback;
pub mod webgluniformlocation;
pub mod webglvertexarrayobject;
pub mod webglvertexarrayobjectoes;
pub mod websocket;
pub mod wheelevent;
pub mod window;
pub mod windowproxy;
pub mod worker;
pub mod workerglobalscope;
pub mod workerlocation;
pub mod workernavigator;
pub mod worklet;
pub mod workletglobalscope;
pub mod xmldocument;
pub mod xmlhttprequest;
pub mod xmlhttprequesteventtarget;
pub mod xmlhttprequestupload;
pub mod xmlserializer;
pub mod xrcompositionlayer;
pub mod xrcubelayer;
pub mod xrcylinderlayer;
pub mod xrequirectlayer;
pub mod xrframe;
pub mod xrhand;
pub mod xrhittestresult;
pub mod xrhittestsource;
pub mod xrinputsource;
pub mod xrinputsourcearray;
pub mod xrinputsourceevent;
pub mod xrinputsourceschangeevent;
pub mod xrjointpose;
pub mod xrjointspace;
pub mod xrlayer;
pub mod xrlayerevent;
pub mod xrmediabinding;
pub mod xrpose;
pub mod xrprojectionlayer;
pub mod xrquadlayer;
pub mod xrray;
pub mod xrreferencespace;
pub mod xrrenderstate;
pub mod xrrigidtransform;
pub mod xrsession;
pub mod xrsessionevent;
pub mod xrspace;
pub mod xrsubimage;
pub mod xrsystem;
pub mod xrtest;
pub mod xrview;
pub mod xrviewerpose;
pub mod xrviewport;
pub mod xrwebglbinding;
pub mod xrwebgllayer;
pub mod xrwebglsubimage;
pub use self::webgl_extensions::ext::*;