1 /* This Source Code Form is subject to the terms of the Mozilla Public
2 * License, v. 2.0. If a copy of the MPL was not distributed with this
3 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
4
5 //! Parsed representations of [DOM attributes][attr].
6 //!
7 //! [attr]: https://dom.spec.whatwg.org/#interface-attr
8
9 use crate::properties::PropertyDeclarationBlock;
10 use crate::shared_lock::Locked;
11 use crate::str::str_join;
12 use crate::str::{read_exponent, read_fraction, HTML_SPACE_CHARACTERS};
13 use crate::str::{read_numbers, split_commas, split_html_space_chars};
14 use crate::values::specified::Length;
15 use crate::values::AtomString;
16 use crate::{Atom, LocalName, Namespace, Prefix};
17 use app_units::Au;
18 use cssparser::{self, Color, RGBA};
19 use euclid::num::Zero;
20 use num_traits::ToPrimitive;
21 use selectors::attr::AttrSelectorOperation;
22 use servo_arc::Arc;
23 use servo_url::ServoUrl;
24 use std::str::FromStr;
25
26 // Duplicated from script::dom::values.
27 const UNSIGNED_LONG_MAX: u32 = 2147483647;
28
29 #[derive(Clone, Copy, Debug, PartialEq)]
30 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
31 pub enum LengthOrPercentageOrAuto {
32 Auto,
33 Percentage(f32),
34 Length(Au),
35 }
36
37 #[derive(Clone, Debug)]
38 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
39 pub enum AttrValue {
40 String(String),
41 TokenList(String, Vec<Atom>),
42 UInt(String, u32),
43 Int(String, i32),
44 Double(String, f64),
45 Atom(Atom),
46 Length(String, Option<Length>),
47 Color(String, Option<RGBA>),
48 Dimension(String, LengthOrPercentageOrAuto),
49
50 /// Stores a URL, computed from the input string and a document's base URL.
51 ///
52 /// The URL is resolved at setting-time, so this kind of attribute value is
53 /// not actually suitable for most URL-reflecting IDL attributes.
54 ResolvedUrl(String, Option<ServoUrl>),
55
56 /// Note that this variant is only used transitively as a fast path to set
57 /// the property declaration block relevant to the style of an element when
58 /// set from the inline declaration of that element (that is,
59 /// `element.style`).
60 ///
61 /// This can, as of this writing, only correspond to the value of the
62 /// `style` element, and is set from its relevant CSSInlineStyleDeclaration,
63 /// and then converted to a string in Element::attribute_mutated.
64 ///
65 /// Note that we don't necessarily need to do that (we could just clone the
66 /// declaration block), but that avoids keeping a refcounted
67 /// declarationblock for longer than needed.
68 Declaration(
69 String,
70 #[ignore_malloc_size_of = "Arc"] Arc<Locked<PropertyDeclarationBlock>>,
71 ),
72 }
73
74 /// Shared implementation to parse an integer according to
75 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-integers> or
76 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-negative-integers>
do_parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i64, ()>77 fn do_parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i64, ()> {
78 let mut input = input
79 .skip_while(|c| HTML_SPACE_CHARACTERS.iter().any(|s| s == c))
80 .peekable();
81
82 let sign = match input.peek() {
83 None => return Err(()),
84 Some(&'-') => {
85 input.next();
86 -1
87 },
88 Some(&'+') => {
89 input.next();
90 1
91 },
92 Some(_) => 1,
93 };
94
95 let (value, _) = read_numbers(input);
96
97 value.and_then(|value| value.checked_mul(sign)).ok_or(())
98 }
99
100 /// Parse an integer according to
101 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-integers>.
parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i32, ()>102 pub fn parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i32, ()> {
103 do_parse_integer(input).and_then(|result| result.to_i32().ok_or(()))
104 }
105
106 /// Parse an integer according to
107 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-negative-integers>
parse_unsigned_integer<T: Iterator<Item = char>>(input: T) -> Result<u32, ()>108 pub fn parse_unsigned_integer<T: Iterator<Item = char>>(input: T) -> Result<u32, ()> {
109 do_parse_integer(input).and_then(|result| result.to_u32().ok_or(()))
110 }
111
112 /// Parse a floating-point number according to
113 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-floating-point-number-values>
parse_double(string: &str) -> Result<f64, ()>114 pub fn parse_double(string: &str) -> Result<f64, ()> {
115 let trimmed = string.trim_matches(HTML_SPACE_CHARACTERS);
116 let mut input = trimmed.chars().peekable();
117
118 let (value, divisor, chars_skipped) = match input.peek() {
119 None => return Err(()),
120 Some(&'-') => {
121 input.next();
122 (-1f64, -1f64, 1)
123 },
124 Some(&'+') => {
125 input.next();
126 (1f64, 1f64, 1)
127 },
128 _ => (1f64, 1f64, 0),
129 };
130
131 let (value, value_digits) = if let Some(&'.') = input.peek() {
132 (0f64, 0)
133 } else {
134 let (read_val, read_digits) = read_numbers(input);
135 (
136 value * read_val.and_then(|result| result.to_f64()).unwrap_or(1f64),
137 read_digits,
138 )
139 };
140
141 let input = trimmed
142 .chars()
143 .skip(value_digits + chars_skipped)
144 .peekable();
145
146 let (mut value, fraction_digits) = read_fraction(input, divisor, value);
147
148 let input = trimmed
149 .chars()
150 .skip(value_digits + chars_skipped + fraction_digits)
151 .peekable();
152
153 if let Some(exp) = read_exponent(input) {
154 value *= 10f64.powi(exp)
155 };
156
157 Ok(value)
158 }
159
160 impl AttrValue {
from_serialized_tokenlist(tokens: String) -> AttrValue161 pub fn from_serialized_tokenlist(tokens: String) -> AttrValue {
162 let atoms =
163 split_html_space_chars(&tokens)
164 .map(Atom::from)
165 .fold(vec![], |mut acc, atom| {
166 if !acc.contains(&atom) {
167 acc.push(atom)
168 }
169 acc
170 });
171 AttrValue::TokenList(tokens, atoms)
172 }
173
from_comma_separated_tokenlist(tokens: String) -> AttrValue174 pub fn from_comma_separated_tokenlist(tokens: String) -> AttrValue {
175 let atoms = split_commas(&tokens)
176 .map(Atom::from)
177 .fold(vec![], |mut acc, atom| {
178 if !acc.contains(&atom) {
179 acc.push(atom)
180 }
181 acc
182 });
183 AttrValue::TokenList(tokens, atoms)
184 }
185
from_atomic_tokens(atoms: Vec<Atom>) -> AttrValue186 pub fn from_atomic_tokens(atoms: Vec<Atom>) -> AttrValue {
187 // TODO(ajeffrey): effecient conversion of Vec<Atom> to String
188 let tokens = String::from(str_join(&atoms, "\x20"));
189 AttrValue::TokenList(tokens, atoms)
190 }
191
192 // https://html.spec.whatwg.org/multipage/#reflecting-content-attributes-in-idl-attributes:idl-unsigned-long
from_u32(string: String, default: u32) -> AttrValue193 pub fn from_u32(string: String, default: u32) -> AttrValue {
194 let result = parse_unsigned_integer(string.chars()).unwrap_or(default);
195 let result = if result > UNSIGNED_LONG_MAX {
196 default
197 } else {
198 result
199 };
200 AttrValue::UInt(string, result)
201 }
202
from_i32(string: String, default: i32) -> AttrValue203 pub fn from_i32(string: String, default: i32) -> AttrValue {
204 let result = parse_integer(string.chars()).unwrap_or(default);
205 AttrValue::Int(string, result)
206 }
207
208 // https://html.spec.whatwg.org/multipage/#reflecting-content-attributes-in-idl-attributes:idl-double
from_double(string: String, default: f64) -> AttrValue209 pub fn from_double(string: String, default: f64) -> AttrValue {
210 let result = parse_double(&string).unwrap_or(default);
211
212 if result.is_normal() {
213 AttrValue::Double(string, result)
214 } else {
215 AttrValue::Double(string, default)
216 }
217 }
218
219 // https://html.spec.whatwg.org/multipage/#limited-to-only-non-negative-numbers
from_limited_i32(string: String, default: i32) -> AttrValue220 pub fn from_limited_i32(string: String, default: i32) -> AttrValue {
221 let result = parse_integer(string.chars()).unwrap_or(default);
222
223 if result < 0 {
224 AttrValue::Int(string, default)
225 } else {
226 AttrValue::Int(string, result)
227 }
228 }
229
230 // https://html.spec.whatwg.org/multipage/#limited-to-only-non-negative-numbers-greater-than-zero
from_limited_u32(string: String, default: u32) -> AttrValue231 pub fn from_limited_u32(string: String, default: u32) -> AttrValue {
232 let result = parse_unsigned_integer(string.chars()).unwrap_or(default);
233 let result = if result == 0 || result > UNSIGNED_LONG_MAX {
234 default
235 } else {
236 result
237 };
238 AttrValue::UInt(string, result)
239 }
240
from_atomic(string: String) -> AttrValue241 pub fn from_atomic(string: String) -> AttrValue {
242 let value = Atom::from(string);
243 AttrValue::Atom(value)
244 }
245
from_resolved_url(base: &ServoUrl, url: String) -> AttrValue246 pub fn from_resolved_url(base: &ServoUrl, url: String) -> AttrValue {
247 let joined = base.join(&url).ok();
248 AttrValue::ResolvedUrl(url, joined)
249 }
250
from_legacy_color(string: String) -> AttrValue251 pub fn from_legacy_color(string: String) -> AttrValue {
252 let parsed = parse_legacy_color(&string).ok();
253 AttrValue::Color(string, parsed)
254 }
255
from_dimension(string: String) -> AttrValue256 pub fn from_dimension(string: String) -> AttrValue {
257 let parsed = parse_length(&string);
258 AttrValue::Dimension(string, parsed)
259 }
260
from_nonzero_dimension(string: String) -> AttrValue261 pub fn from_nonzero_dimension(string: String) -> AttrValue {
262 let parsed = parse_nonzero_length(&string);
263 AttrValue::Dimension(string, parsed)
264 }
265
266 /// Assumes the `AttrValue` is a `TokenList` and returns its tokens
267 ///
268 /// ## Panics
269 ///
270 /// Panics if the `AttrValue` is not a `TokenList`
as_tokens(&self) -> &[Atom]271 pub fn as_tokens(&self) -> &[Atom] {
272 match *self {
273 AttrValue::TokenList(_, ref tokens) => tokens,
274 _ => panic!("Tokens not found"),
275 }
276 }
277
278 /// Assumes the `AttrValue` is an `Atom` and returns its value
279 ///
280 /// ## Panics
281 ///
282 /// Panics if the `AttrValue` is not an `Atom`
as_atom(&self) -> &Atom283 pub fn as_atom(&self) -> &Atom {
284 match *self {
285 AttrValue::Atom(ref value) => value,
286 _ => panic!("Atom not found"),
287 }
288 }
289
290 /// Assumes the `AttrValue` is a `Color` and returns its value
291 ///
292 /// ## Panics
293 ///
294 /// Panics if the `AttrValue` is not a `Color`
as_color(&self) -> Option<&RGBA>295 pub fn as_color(&self) -> Option<&RGBA> {
296 match *self {
297 AttrValue::Color(_, ref color) => color.as_ref(),
298 _ => panic!("Color not found"),
299 }
300 }
301
302 /// Assumes the `AttrValue` is a `Dimension` and returns its value
303 ///
304 /// ## Panics
305 ///
306 /// Panics if the `AttrValue` is not a `Dimension`
as_dimension(&self) -> &LengthOrPercentageOrAuto307 pub fn as_dimension(&self) -> &LengthOrPercentageOrAuto {
308 match *self {
309 AttrValue::Dimension(_, ref l) => l,
310 _ => panic!("Dimension not found"),
311 }
312 }
313
314 /// Assumes the `AttrValue` is a `ResolvedUrl` and returns its value.
315 ///
316 /// ## Panics
317 ///
318 /// Panics if the `AttrValue` is not a `ResolvedUrl`
as_resolved_url(&self) -> Option<&ServoUrl>319 pub fn as_resolved_url(&self) -> Option<&ServoUrl> {
320 match *self {
321 AttrValue::ResolvedUrl(_, ref url) => url.as_ref(),
322 _ => panic!("Url not found"),
323 }
324 }
325
326 /// Return the AttrValue as its integer representation, if any.
327 /// This corresponds to attribute values returned as `AttrValue::UInt(_)`
328 /// by `VirtualMethods::parse_plain_attribute()`.
329 ///
330 /// ## Panics
331 ///
332 /// Panics if the `AttrValue` is not a `UInt`
as_uint(&self) -> u32333 pub fn as_uint(&self) -> u32 {
334 if let AttrValue::UInt(_, value) = *self {
335 value
336 } else {
337 panic!("Uint not found");
338 }
339 }
340
341 /// Return the AttrValue as a dimension computed from its integer
342 /// representation, assuming that integer representation specifies pixels.
343 ///
344 /// This corresponds to attribute values returned as `AttrValue::UInt(_)`
345 /// by `VirtualMethods::parse_plain_attribute()`.
346 ///
347 /// ## Panics
348 ///
349 /// Panics if the `AttrValue` is not a `UInt`
as_uint_px_dimension(&self) -> LengthOrPercentageOrAuto350 pub fn as_uint_px_dimension(&self) -> LengthOrPercentageOrAuto {
351 if let AttrValue::UInt(_, value) = *self {
352 LengthOrPercentageOrAuto::Length(Au::from_px(value as i32))
353 } else {
354 panic!("Uint not found");
355 }
356 }
357
eval_selector(&self, selector: &AttrSelectorOperation<&AtomString>) -> bool358 pub fn eval_selector(&self, selector: &AttrSelectorOperation<&AtomString>) -> bool {
359 // FIXME(SimonSapin) this can be more efficient by matching on `(self, selector)` variants
360 // and doing Atom comparisons instead of string comparisons where possible,
361 // with SelectorImpl::AttrValue changed to Atom.
362 selector.eval_str(self)
363 }
364 }
365
366 impl ::std::ops::Deref for AttrValue {
367 type Target = str;
368
deref(&self) -> &str369 fn deref(&self) -> &str {
370 match *self {
371 AttrValue::String(ref value) |
372 AttrValue::TokenList(ref value, _) |
373 AttrValue::UInt(ref value, _) |
374 AttrValue::Double(ref value, _) |
375 AttrValue::Length(ref value, _) |
376 AttrValue::Color(ref value, _) |
377 AttrValue::Int(ref value, _) |
378 AttrValue::ResolvedUrl(ref value, _) |
379 AttrValue::Declaration(ref value, _) |
380 AttrValue::Dimension(ref value, _) => &value,
381 AttrValue::Atom(ref value) => &value,
382 }
383 }
384 }
385
386 impl PartialEq<Atom> for AttrValue {
eq(&self, other: &Atom) -> bool387 fn eq(&self, other: &Atom) -> bool {
388 match *self {
389 AttrValue::Atom(ref value) => value == other,
390 _ => other == &**self,
391 }
392 }
393 }
394
395 /// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-zero-dimension-values>
parse_nonzero_length(value: &str) -> LengthOrPercentageOrAuto396 pub fn parse_nonzero_length(value: &str) -> LengthOrPercentageOrAuto {
397 match parse_length(value) {
398 LengthOrPercentageOrAuto::Length(x) if x == Au::zero() => LengthOrPercentageOrAuto::Auto,
399 LengthOrPercentageOrAuto::Percentage(x) if x == 0. => LengthOrPercentageOrAuto::Auto,
400 x => x,
401 }
402 }
403
404 /// Parses a [legacy color][color]. If unparseable, `Err` is returned.
405 ///
406 /// [color]: https://html.spec.whatwg.org/multipage/#rules-for-parsing-a-legacy-colour-value
parse_legacy_color(mut input: &str) -> Result<RGBA, ()>407 pub fn parse_legacy_color(mut input: &str) -> Result<RGBA, ()> {
408 // Steps 1 and 2.
409 if input.is_empty() {
410 return Err(());
411 }
412
413 // Step 3.
414 input = input.trim_matches(HTML_SPACE_CHARACTERS);
415
416 // Step 4.
417 if input.eq_ignore_ascii_case("transparent") {
418 return Err(());
419 }
420
421 // Step 5.
422 if let Ok(Color::RGBA(rgba)) = cssparser::parse_color_keyword(input) {
423 return Ok(rgba);
424 }
425
426 // Step 6.
427 if input.len() == 4 {
428 if let (b'#', Ok(r), Ok(g), Ok(b)) = (
429 input.as_bytes()[0],
430 hex(input.as_bytes()[1] as char),
431 hex(input.as_bytes()[2] as char),
432 hex(input.as_bytes()[3] as char),
433 ) {
434 return Ok(RGBA::new(r * 17, g * 17, b * 17, 255));
435 }
436 }
437
438 // Step 7.
439 let mut new_input = String::new();
440 for ch in input.chars() {
441 if ch as u32 > 0xffff {
442 new_input.push_str("00")
443 } else {
444 new_input.push(ch)
445 }
446 }
447 let mut input = &*new_input;
448
449 // Step 8.
450 for (char_count, (index, _)) in input.char_indices().enumerate() {
451 if char_count == 128 {
452 input = &input[..index];
453 break;
454 }
455 }
456
457 // Step 9.
458 if input.as_bytes()[0] == b'#' {
459 input = &input[1..]
460 }
461
462 // Step 10.
463 let mut new_input = Vec::new();
464 for ch in input.chars() {
465 if hex(ch).is_ok() {
466 new_input.push(ch as u8)
467 } else {
468 new_input.push(b'0')
469 }
470 }
471 let mut input = new_input;
472
473 // Step 11.
474 while input.is_empty() || (input.len() % 3) != 0 {
475 input.push(b'0')
476 }
477
478 // Step 12.
479 let mut length = input.len() / 3;
480 let (mut red, mut green, mut blue) = (
481 &input[..length],
482 &input[length..length * 2],
483 &input[length * 2..],
484 );
485
486 // Step 13.
487 if length > 8 {
488 red = &red[length - 8..];
489 green = &green[length - 8..];
490 blue = &blue[length - 8..];
491 length = 8
492 }
493
494 // Step 14.
495 while length > 2 && red[0] == b'0' && green[0] == b'0' && blue[0] == b'0' {
496 red = &red[1..];
497 green = &green[1..];
498 blue = &blue[1..];
499 length -= 1
500 }
501
502 // Steps 15-20.
503 return Ok(RGBA::new(
504 hex_string(red).unwrap(),
505 hex_string(green).unwrap(),
506 hex_string(blue).unwrap(),
507 255,
508 ));
509
510 fn hex(ch: char) -> Result<u8, ()> {
511 match ch {
512 '0'..='9' => Ok((ch as u8) - b'0'),
513 'a'..='f' => Ok((ch as u8) - b'a' + 10),
514 'A'..='F' => Ok((ch as u8) - b'A' + 10),
515 _ => Err(()),
516 }
517 }
518
519 fn hex_string(string: &[u8]) -> Result<u8, ()> {
520 match string.len() {
521 0 => Err(()),
522 1 => hex(string[0] as char),
523 _ => {
524 let upper = hex(string[0] as char)?;
525 let lower = hex(string[1] as char)?;
526 Ok((upper << 4) | lower)
527 },
528 }
529 }
530 }
531
532 /// Parses a [dimension value][dim]. If unparseable, `Auto` is returned.
533 ///
534 /// [dim]: https://html.spec.whatwg.org/multipage/#rules-for-parsing-dimension-values
535 // TODO: this function can be rewritten to return Result<LengthPercentage, _>
parse_length(mut value: &str) -> LengthOrPercentageOrAuto536 pub fn parse_length(mut value: &str) -> LengthOrPercentageOrAuto {
537 // Steps 1 & 2 are not relevant
538
539 // Step 3
540 value = value.trim_start_matches(HTML_SPACE_CHARACTERS);
541
542 // Step 4
543 match value.chars().nth(0) {
544 Some('0'..='9') => {},
545 _ => return LengthOrPercentageOrAuto::Auto,
546 }
547
548 // Steps 5 to 8
549 // We trim the string length to the minimum of:
550 // 1. the end of the string
551 // 2. the first occurence of a '%' (U+0025 PERCENT SIGN)
552 // 3. the second occurrence of a '.' (U+002E FULL STOP)
553 // 4. the occurrence of a character that is neither a digit nor '%' nor '.'
554 // Note: Step 7.4 is directly subsumed by FromStr::from_str
555 let mut end_index = value.len();
556 let (mut found_full_stop, mut found_percent) = (false, false);
557 for (i, ch) in value.chars().enumerate() {
558 match ch {
559 '0'..='9' => continue,
560 '%' => {
561 found_percent = true;
562 end_index = i;
563 break;
564 },
565 '.' if !found_full_stop => {
566 found_full_stop = true;
567 continue;
568 },
569 _ => {
570 end_index = i;
571 break;
572 },
573 }
574 }
575 value = &value[..end_index];
576
577 if found_percent {
578 let result: Result<f32, _> = FromStr::from_str(value);
579 match result {
580 Ok(number) => return LengthOrPercentageOrAuto::Percentage((number as f32) / 100.0),
581 Err(_) => return LengthOrPercentageOrAuto::Auto,
582 }
583 }
584
585 match FromStr::from_str(value) {
586 Ok(number) => LengthOrPercentageOrAuto::Length(Au::from_f64_px(number)),
587 Err(_) => LengthOrPercentageOrAuto::Auto,
588 }
589 }
590
591 /// A struct that uniquely identifies an element's attribute.
592 #[derive(Clone, Debug)]
593 #[cfg_attr(feature = "servo", derive(MallocSizeOf))]
594 pub struct AttrIdentifier {
595 pub local_name: LocalName,
596 pub name: LocalName,
597 pub namespace: Namespace,
598 pub prefix: Option<Prefix>,
599 }
600