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
/* 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/. */

//! Style sheets and their CSS rules.

pub mod container_rule;
mod counter_style_rule;
mod document_rule;
mod font_face_rule;
pub mod font_feature_values_rule;
pub mod font_palette_values_rule;
pub mod import_rule;
pub mod keyframes_rule;
pub mod layer_rule;
mod loader;
mod media_rule;
mod namespace_rule;
pub mod origin;
mod page_rule;
mod property_rule;
mod rule_list;
mod rule_parser;
mod rules_iterator;
mod style_rule;
mod stylesheet;
pub mod supports_rule;

#[cfg(feature = "gecko")]
use crate::gecko_bindings::sugar::refptr::RefCounted;
#[cfg(feature = "gecko")]
use crate::gecko_bindings::{bindings, structs};
use crate::parser::ParserContext;
use crate::shared_lock::{DeepCloneParams, DeepCloneWithLock, Locked};
use crate::shared_lock::{SharedRwLock, SharedRwLockReadGuard, ToCssWithGuard};
use crate::str::CssStringWriter;
use cssparser::{parse_one_rule, Parser, ParserInput};
#[cfg(feature = "gecko")]
use malloc_size_of::{MallocSizeOfOps, MallocUnconditionalShallowSizeOf};
use servo_arc::Arc;
use std::borrow::Cow;
use std::fmt;
#[cfg(feature = "gecko")]
use std::mem::{self, ManuallyDrop};
use style_traits::ParsingMode;
use to_shmem::{self, SharedMemoryBuilder, ToShmem};

pub use self::container_rule::ContainerRule;
pub use self::counter_style_rule::CounterStyleRule;
pub use self::document_rule::DocumentRule;
pub use self::font_face_rule::FontFaceRule;
pub use self::font_feature_values_rule::FontFeatureValuesRule;
pub use self::font_palette_values_rule::FontPaletteValuesRule;
pub use self::import_rule::ImportRule;
pub use self::keyframes_rule::KeyframesRule;
pub use self::layer_rule::{LayerBlockRule, LayerStatementRule};
pub use self::loader::StylesheetLoader;
pub use self::media_rule::MediaRule;
pub use self::namespace_rule::NamespaceRule;
pub use self::origin::{Origin, OriginSet, OriginSetIterator, PerOrigin, PerOriginIter};
pub use self::property_rule::PropertyRule;
pub use self::page_rule::{PageRule, PagePseudoClassFlags, PageSelector, PageSelectors};
pub use self::rule_list::{CssRules, CssRulesHelpers};
pub use self::rule_parser::{InsertRuleContext, State, TopLevelRuleParser};
pub use self::rules_iterator::{AllRules, EffectiveRules};
pub use self::rules_iterator::{
    EffectiveRulesIterator, NestedRuleIterationCondition, RulesIterator,
};
pub use self::style_rule::StyleRule;
pub use self::stylesheet::{AllowImportRules, SanitizationData, SanitizationKind};
pub use self::stylesheet::{DocumentStyleSheet, Namespaces, Stylesheet};
pub use self::stylesheet::{StylesheetContents, StylesheetInDocument, UserAgentStylesheets};
pub use self::supports_rule::SupportsRule;

/// The CORS mode used for a CSS load.
#[repr(u8)]
#[derive(Clone, Copy, Debug, Eq, PartialEq, ToShmem)]
pub enum CorsMode {
    /// No CORS mode, so cross-origin loads can be done.
    None,
    /// Anonymous CORS request.
    Anonymous,
}

/// Extra data that the backend may need to resolve url values.
///
/// If the usize's lowest bit is 0, then this is a strong reference to a
/// structs::URLExtraData object.
///
/// Otherwise, shifting the usize's bits the right by one gives the
/// UserAgentStyleSheetID value corresponding to the style sheet whose
/// URLExtraData this is, which is stored in URLExtraData_sShared.  We don't
/// hold a strong reference to that object from here, but we rely on that
/// array's objects being held alive until shutdown.
///
/// We use this packed representation rather than an enum so that
/// `from_ptr_ref` can work.
#[cfg(feature = "gecko")]
// Although deriving MallocSizeOf means it always returns 0, that is fine because UrlExtraData
// objects are reference-counted.
#[derive(MallocSizeOf, PartialEq)]
#[repr(C)]
pub struct UrlExtraData(usize);

/// Extra data that the backend may need to resolve url values.
#[cfg(feature = "servo")]
#[derive(Clone, Debug, Eq, MallocSizeOf, PartialEq)]
pub struct UrlExtraData(#[ignore_malloc_size_of = "Arc"] pub Arc<::url::Url>);

#[cfg(feature = "servo")]
impl UrlExtraData {
    /// True if this URL scheme is chrome.
    pub fn chrome_rules_enabled(&self) -> bool {
        self.0.scheme() == "chrome"
    }

    /// Get the interior Url as a string.
    pub fn as_str(&self) -> &str {
        self.0.as_str()
    }
}

#[cfg(feature = "servo")]
impl From<::url::Url> for UrlExtraData {
    fn from(url: ::url::Url) -> Self {
        Self(Arc::new(url))
    }
}

#[cfg(not(feature = "gecko"))]
impl ToShmem for UrlExtraData {
    fn to_shmem(&self, _builder: &mut SharedMemoryBuilder) -> to_shmem::Result<Self> {
        unimplemented!("If servo wants to share stylesheets across processes, ToShmem for Url must be implemented");
    }
}

#[cfg(feature = "gecko")]
impl Clone for UrlExtraData {
    fn clone(&self) -> UrlExtraData {
        UrlExtraData::new(self.ptr())
    }
}

#[cfg(feature = "gecko")]
impl Drop for UrlExtraData {
    fn drop(&mut self) {
        // No need to release when we have an index into URLExtraData_sShared.
        if self.0 & 1 == 0 {
            unsafe {
                self.as_ref().release();
            }
        }
    }
}

#[cfg(feature = "gecko")]
impl ToShmem for UrlExtraData {
    fn to_shmem(&self, _builder: &mut SharedMemoryBuilder) -> to_shmem::Result<Self> {
        if self.0 & 1 == 0 {
            let shared_extra_datas = unsafe { &structs::URLExtraData_sShared };
            let self_ptr = self.as_ref() as *const _ as *mut _;
            let sheet_id = shared_extra_datas
                .iter()
                .position(|r| r.mRawPtr == self_ptr);
            let sheet_id = match sheet_id {
                Some(id) => id,
                None => {
                    return Err(String::from(
                        "ToShmem failed for UrlExtraData: expected sheet's URLExtraData to be in \
                         URLExtraData::sShared",
                    ));
                },
            };
            Ok(ManuallyDrop::new(UrlExtraData((sheet_id << 1) | 1)))
        } else {
            Ok(ManuallyDrop::new(UrlExtraData(self.0)))
        }
    }
}

#[cfg(feature = "gecko")]
impl UrlExtraData {
    /// Create a new UrlExtraData wrapping a pointer to the specified Gecko
    /// URLExtraData object.
    pub fn new(ptr: *mut structs::URLExtraData) -> UrlExtraData {
        unsafe {
            (*ptr).addref();
        }
        UrlExtraData(ptr as usize)
    }

    /// True if this URL scheme is chrome.
    #[inline]
    pub fn chrome_rules_enabled(&self) -> bool {
        self.as_ref().mChromeRulesEnabled
    }

    /// Create a reference to this `UrlExtraData` from a reference to pointer.
    ///
    /// The pointer must be valid and non null.
    ///
    /// This method doesn't touch refcount.
    #[inline]
    pub unsafe fn from_ptr_ref(ptr: &*mut structs::URLExtraData) -> &Self {
        mem::transmute(ptr)
    }

    /// Returns a pointer to the Gecko URLExtraData object.
    pub fn ptr(&self) -> *mut structs::URLExtraData {
        if self.0 & 1 == 0 {
            self.0 as *mut structs::URLExtraData
        } else {
            unsafe {
                let sheet_id = self.0 >> 1;
                structs::URLExtraData_sShared[sheet_id].mRawPtr
            }
        }
    }

    fn as_ref(&self) -> &structs::URLExtraData {
        unsafe { &*(self.ptr() as *const structs::URLExtraData) }
    }
}

#[cfg(feature = "gecko")]
impl fmt::Debug for UrlExtraData {
    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
        macro_rules! define_debug_struct {
            ($struct_name:ident, $gecko_class:ident, $debug_fn:ident) => {
                struct $struct_name(*mut structs::$gecko_class);
                impl fmt::Debug for $struct_name {
                    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
                        use nsstring::nsCString;
                        let mut spec = nsCString::new();
                        unsafe {
                            bindings::$debug_fn(self.0, &mut spec);
                        }
                        spec.fmt(formatter)
                    }
                }
            };
        }

        define_debug_struct!(DebugURI, nsIURI, Gecko_nsIURI_Debug);
        define_debug_struct!(
            DebugReferrerInfo,
            nsIReferrerInfo,
            Gecko_nsIReferrerInfo_Debug
        );

        formatter
            .debug_struct("URLExtraData")
            .field("chrome_rules_enabled", &self.chrome_rules_enabled())
            .field("base", &DebugURI(self.as_ref().mBaseURI.raw()))
            .field(
                "referrer",
                &DebugReferrerInfo(self.as_ref().mReferrerInfo.raw()),
            )
            .finish()
    }
}

// XXX We probably need to figure out whether we should mark Eq here.
// It is currently marked so because properties::UnparsedValue wants Eq.
#[cfg(feature = "gecko")]
impl Eq for UrlExtraData {}

/// A CSS rule.
///
/// TODO(emilio): Lots of spec links should be around.
#[derive(Clone, Debug, ToShmem)]
#[allow(missing_docs)]
pub enum CssRule {
    // No Charset here, CSSCharsetRule has been removed from CSSOM
    // https://drafts.csswg.org/cssom/#changes-from-5-december-2013
    Namespace(Arc<NamespaceRule>),
    Import(Arc<Locked<ImportRule>>),
    Style(Arc<Locked<StyleRule>>),
    Media(Arc<MediaRule>),
    Container(Arc<ContainerRule>),
    FontFace(Arc<Locked<FontFaceRule>>),
    FontFeatureValues(Arc<FontFeatureValuesRule>),
    FontPaletteValues(Arc<FontPaletteValuesRule>),
    CounterStyle(Arc<Locked<CounterStyleRule>>),
    Keyframes(Arc<Locked<KeyframesRule>>),
    Supports(Arc<SupportsRule>),
    Page(Arc<Locked<PageRule>>),
    Property(Arc<PropertyRule>),
    Document(Arc<DocumentRule>),
    LayerBlock(Arc<LayerBlockRule>),
    LayerStatement(Arc<LayerStatementRule>),
}

impl CssRule {
    /// Measure heap usage.
    #[cfg(feature = "gecko")]
    fn size_of(&self, guard: &SharedRwLockReadGuard, ops: &mut MallocSizeOfOps) -> usize {
        match *self {
            // Not all fields are currently fully measured. Extra measurement
            // may be added later.
            CssRule::Namespace(_) => 0,

            // We don't need to measure ImportRule::stylesheet because we measure
            // it on the C++ side in the child list of the ServoStyleSheet.
            CssRule::Import(_) => 0,

            CssRule::Style(ref lock) => {
                lock.unconditional_shallow_size_of(ops) + lock.read_with(guard).size_of(guard, ops)
            },
            CssRule::Media(ref arc) => {
                arc.unconditional_shallow_size_of(ops) + arc.size_of(guard, ops)
            },
            CssRule::Container(ref arc) => {
                arc.unconditional_shallow_size_of(ops) + arc.size_of(guard, ops)
            },
            CssRule::FontFace(_) => 0,
            CssRule::FontFeatureValues(_) => 0,
            CssRule::FontPaletteValues(_) => 0,
            CssRule::CounterStyle(_) => 0,
            CssRule::Keyframes(_) => 0,
            CssRule::Supports(ref arc) => {
                arc.unconditional_shallow_size_of(ops) + arc.size_of(guard, ops)
            },
            CssRule::Page(ref lock) => {
                lock.unconditional_shallow_size_of(ops) + lock.read_with(guard).size_of(guard, ops)
            },
            CssRule::Property(ref rule) => {
                rule.unconditional_shallow_size_of(ops) + rule.size_of(guard, ops)
            },
            CssRule::Document(ref arc) => {
                arc.unconditional_shallow_size_of(ops) + arc.size_of(guard, ops)
            },
            // TODO(emilio): Add memory reporting for these rules.
            CssRule::LayerBlock(_) | CssRule::LayerStatement(_) => 0,
        }
    }
}

/// https://drafts.csswg.org/cssom-1/#dom-cssrule-type
#[allow(missing_docs)]
#[derive(Clone, Copy, Debug, Eq, FromPrimitive, PartialEq)]
#[repr(u8)]
pub enum CssRuleType {
    // https://drafts.csswg.org/cssom/#the-cssrule-interface
    Style = 1,
    // Charset = 2, // Historical
    Import = 3,
    Media = 4,
    FontFace = 5,
    Page = 6,
    // https://drafts.csswg.org/css-animations-1/#interface-cssrule-idl
    Keyframes = 7,
    Keyframe = 8,
    // https://drafts.csswg.org/cssom/#the-cssrule-interface
    // Margin = 9, // Not implemented yet.
    Namespace = 10,
    // https://drafts.csswg.org/css-counter-styles-3/#extentions-to-cssrule-interface
    CounterStyle = 11,
    // https://drafts.csswg.org/css-conditional-3/#extentions-to-cssrule-interface
    Supports = 12,
    // https://www.w3.org/TR/2012/WD-css3-conditional-20120911/#extentions-to-cssrule-interface
    Document = 13,
    // https://drafts.csswg.org/css-fonts/#om-fontfeaturevalues
    FontFeatureValues = 14,
    // After viewport, all rules should return 0 from the API, but we still need
    // a constant somewhere.
    LayerBlock = 16,
    LayerStatement = 17,
    Container = 18,
    FontPaletteValues = 19,
    // 20 is an arbitrary number to use for Property.
    Property = 20,
}

impl CssRuleType {
    /// Returns a bit that identifies this rule type.
    #[inline]
    pub const fn bit(self) -> u32 {
        1 << self as u32
    }
}

/// Set of rule types.
#[derive(Clone, Copy, Debug, Default, Eq, PartialEq)]
pub struct CssRuleTypes(u32);

impl From<CssRuleType> for CssRuleTypes {
    fn from(ty: CssRuleType) -> Self {
        Self(ty.bit())
    }
}

impl CssRuleTypes {
    /// Returns whether the rule is in the current set.
    #[inline]
    pub fn contains(self, ty: CssRuleType) -> bool {
        self.0 & ty.bit() != 0
    }

    /// Returns all the rules specified in the set.
    #[inline]
    pub fn bits(self) -> u32 {
        self.0
    }

    /// Creates a raw CssRuleTypes bitfield.
    #[inline]
    pub fn from_bits(bits: u32) -> Self {
        Self(bits)
    }

    /// Returns whether the rule set is empty.
    #[inline]
    pub fn is_empty(self) -> bool {
        self.0 == 0
    }

    /// Inserts a rule type into the set.
    #[inline]
    pub fn insert(&mut self, ty: CssRuleType) {
        self.0 |= ty.bit()
    }
}

#[allow(missing_docs)]
pub enum RulesMutateError {
    Syntax,
    IndexSize,
    HierarchyRequest,
    InvalidState,
}

impl CssRule {
    /// Returns the CSSOM rule type of this rule.
    pub fn rule_type(&self) -> CssRuleType {
        match *self {
            CssRule::Style(_) => CssRuleType::Style,
            CssRule::Import(_) => CssRuleType::Import,
            CssRule::Media(_) => CssRuleType::Media,
            CssRule::FontFace(_) => CssRuleType::FontFace,
            CssRule::FontFeatureValues(_) => CssRuleType::FontFeatureValues,
            CssRule::FontPaletteValues(_) => CssRuleType::FontPaletteValues,
            CssRule::CounterStyle(_) => CssRuleType::CounterStyle,
            CssRule::Keyframes(_) => CssRuleType::Keyframes,
            CssRule::Namespace(_) => CssRuleType::Namespace,
            CssRule::Supports(_) => CssRuleType::Supports,
            CssRule::Page(_) => CssRuleType::Page,
            CssRule::Property(_) => CssRuleType::Property,
            CssRule::Document(_) => CssRuleType::Document,
            CssRule::LayerBlock(_) => CssRuleType::LayerBlock,
            CssRule::LayerStatement(_) => CssRuleType::LayerStatement,
            CssRule::Container(_) => CssRuleType::Container,
        }
    }

    /// Parse a CSS rule.
    ///
    /// Returns a parsed CSS rule and the final state of the parser.
    ///
    /// Input state is None for a nested rule
    pub fn parse(
        css: &str,
        insert_rule_context: InsertRuleContext,
        parent_stylesheet_contents: &StylesheetContents,
        shared_lock: &SharedRwLock,
        loader: Option<&dyn StylesheetLoader>,
        allow_import_rules: AllowImportRules,
    ) -> Result<Self, RulesMutateError> {
        let url_data = parent_stylesheet_contents.url_data.read();
        let namespaces = parent_stylesheet_contents.namespaces.read();
        let mut context = ParserContext::new(
            parent_stylesheet_contents.origin,
            &url_data,
            None,
            ParsingMode::DEFAULT,
            parent_stylesheet_contents.quirks_mode,
            Cow::Borrowed(&*namespaces),
            None,
            None,
        );
        context.rule_types = insert_rule_context.containing_rule_types;

        let state = if !insert_rule_context.containing_rule_types.is_empty() {
            State::Body
        } else if insert_rule_context.index == 0 {
            State::Start
        } else {
            let index = insert_rule_context.index;
            insert_rule_context.max_rule_state_at_index(index - 1)
        };

        let mut input = ParserInput::new(css);
        let mut input = Parser::new(&mut input);

        // nested rules are in the body state
        let mut rule_parser = TopLevelRuleParser {
            context,
            shared_lock: &shared_lock,
            loader,
            state,
            dom_error: None,
            insert_rule_context: Some(insert_rule_context),
            allow_import_rules,
            declaration_parser_state: Default::default(),
            error_reporting_state: Default::default(),
            rules: Default::default(),
        };

        match parse_one_rule(&mut input, &mut rule_parser) {
            Ok(_) => Ok(rule_parser.rules.pop().unwrap()),
            Err(_) => Err(rule_parser.dom_error.unwrap_or(RulesMutateError::Syntax)),
        }
    }
}

impl DeepCloneWithLock for CssRule {
    /// Deep clones this CssRule.
    fn deep_clone_with_lock(
        &self,
        lock: &SharedRwLock,
        guard: &SharedRwLockReadGuard,
        params: &DeepCloneParams,
    ) -> CssRule {
        match *self {
            CssRule::Namespace(ref arc) => CssRule::Namespace(arc.clone()),
            CssRule::Import(ref arc) => {
                let rule = arc
                    .read_with(guard)
                    .deep_clone_with_lock(lock, guard, params);
                CssRule::Import(Arc::new(lock.wrap(rule)))
            },
            CssRule::Style(ref arc) => {
                let rule = arc.read_with(guard);
                CssRule::Style(Arc::new(
                    lock.wrap(rule.deep_clone_with_lock(lock, guard, params)),
                ))
            },
            CssRule::Container(ref arc) => {
                CssRule::Container(Arc::new(arc.deep_clone_with_lock(lock, guard, params)))
            },
            CssRule::Media(ref arc) => {
                CssRule::Media(Arc::new(arc.deep_clone_with_lock(lock, guard, params)))
            },
            CssRule::FontFace(ref arc) => {
                let rule = arc.read_with(guard);
                CssRule::FontFace(Arc::new(lock.wrap(rule.clone())))
            },
            CssRule::FontFeatureValues(ref arc) => CssRule::FontFeatureValues(arc.clone()),
            CssRule::FontPaletteValues(ref arc) => CssRule::FontPaletteValues(arc.clone()),
            CssRule::CounterStyle(ref arc) => {
                let rule = arc.read_with(guard);
                CssRule::CounterStyle(Arc::new(lock.wrap(rule.clone())))
            },
            CssRule::Keyframes(ref arc) => {
                let rule = arc.read_with(guard);
                CssRule::Keyframes(Arc::new(
                    lock.wrap(rule.deep_clone_with_lock(lock, guard, params)),
                ))
            },
            CssRule::Supports(ref arc) => {
                CssRule::Supports(Arc::new(arc.deep_clone_with_lock(lock, guard, params)))
            },
            CssRule::Page(ref arc) => {
                let rule = arc.read_with(guard);
                CssRule::Page(Arc::new(
                    lock.wrap(rule.deep_clone_with_lock(lock, guard, params)),
                ))
            },
            CssRule::Property(ref arc) => {
                // @property rules are immutable, so we don't need any of the `Locked`
                // shenanigans, actually, and can just share the rule.
                CssRule::Property(arc.clone())
            },
            CssRule::Document(ref arc) => {
                CssRule::Document(Arc::new(arc.deep_clone_with_lock(lock, guard, params)))
            },
            CssRule::LayerStatement(ref arc) => CssRule::LayerStatement(arc.clone()),
            CssRule::LayerBlock(ref arc) => {
                CssRule::LayerBlock(Arc::new(arc.deep_clone_with_lock(lock, guard, params)))
            },
        }
    }
}

impl ToCssWithGuard for CssRule {
    // https://drafts.csswg.org/cssom/#serialize-a-css-rule
    fn to_css(&self, guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
        match *self {
            CssRule::Namespace(ref rule) => rule.to_css(guard, dest),
            CssRule::Import(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::Style(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::FontFace(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::FontFeatureValues(ref rule) => rule.to_css(guard, dest),
            CssRule::FontPaletteValues(ref rule) => rule.to_css(guard, dest),
            CssRule::CounterStyle(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::Keyframes(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::Media(ref rule) => rule.to_css(guard, dest),
            CssRule::Supports(ref rule) => rule.to_css(guard, dest),
            CssRule::Page(ref lock) => lock.read_with(guard).to_css(guard, dest),
            CssRule::Property(ref rule) => rule.to_css(guard, dest),
            CssRule::Document(ref rule) => rule.to_css(guard, dest),
            CssRule::LayerBlock(ref rule) => rule.to_css(guard, dest),
            CssRule::LayerStatement(ref rule) => rule.to_css(guard, dest),
            CssRule::Container(ref rule) => rule.to_css(guard, dest),
        }
    }
}