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+/* 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/. */
+
+//! Parsed representations of [DOM attributes][attr].
+//!
+//! [attr]: https://dom.spec.whatwg.org/#interface-attr
+
+use crate::properties::PropertyDeclarationBlock;
+use crate::shared_lock::Locked;
+use crate::str::str_join;
+use crate::str::{read_exponent, read_fraction, HTML_SPACE_CHARACTERS};
+use crate::str::{read_numbers, split_commas, split_html_space_chars};
+use crate::values::specified::Length;
+use crate::values::AtomString;
+use crate::{Atom, LocalName, Namespace, Prefix};
+use app_units::Au;
+use cssparser::{self, Color, RGBA};
+use euclid::num::Zero;
+use num_traits::ToPrimitive;
+use selectors::attr::AttrSelectorOperation;
+use servo_arc::Arc;
+use servo_url::ServoUrl;
+use std::str::FromStr;
+
+// Duplicated from script::dom::values.
+const UNSIGNED_LONG_MAX: u32 = 2147483647;
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
+pub enum LengthOrPercentageOrAuto {
+ Auto,
+ Percentage(f32),
+ Length(Au),
+}
+
+#[derive(Clone, Debug)]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
+pub enum AttrValue {
+ String(String),
+ TokenList(String, Vec<Atom>),
+ UInt(String, u32),
+ Int(String, i32),
+ Double(String, f64),
+ Atom(Atom),
+ Length(String, Option<Length>),
+ Color(String, Option<RGBA>),
+ Dimension(String, LengthOrPercentageOrAuto),
+
+ /// Stores a URL, computed from the input string and a document's base URL.
+ ///
+ /// The URL is resolved at setting-time, so this kind of attribute value is
+ /// not actually suitable for most URL-reflecting IDL attributes.
+ ResolvedUrl(String, Option<ServoUrl>),
+
+ /// Note that this variant is only used transitively as a fast path to set
+ /// the property declaration block relevant to the style of an element when
+ /// set from the inline declaration of that element (that is,
+ /// `element.style`).
+ ///
+ /// This can, as of this writing, only correspond to the value of the
+ /// `style` element, and is set from its relevant CSSInlineStyleDeclaration,
+ /// and then converted to a string in Element::attribute_mutated.
+ ///
+ /// Note that we don't necessarily need to do that (we could just clone the
+ /// declaration block), but that avoids keeping a refcounted
+ /// declarationblock for longer than needed.
+ Declaration(
+ String,
+ #[ignore_malloc_size_of = "Arc"] Arc<Locked<PropertyDeclarationBlock>>,
+ ),
+}
+
+/// Shared implementation to parse an integer according to
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-integers> or
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-negative-integers>
+fn do_parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i64, ()> {
+ let mut input = input
+ .skip_while(|c| HTML_SPACE_CHARACTERS.iter().any(|s| s == c))
+ .peekable();
+
+ let sign = match input.peek() {
+ None => return Err(()),
+ Some(&'-') => {
+ input.next();
+ -1
+ },
+ Some(&'+') => {
+ input.next();
+ 1
+ },
+ Some(_) => 1,
+ };
+
+ let (value, _) = read_numbers(input);
+
+ value.and_then(|value| value.checked_mul(sign)).ok_or(())
+}
+
+/// Parse an integer according to
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-integers>.
+pub fn parse_integer<T: Iterator<Item = char>>(input: T) -> Result<i32, ()> {
+ do_parse_integer(input).and_then(|result| result.to_i32().ok_or(()))
+}
+
+/// Parse an integer according to
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-negative-integers>
+pub fn parse_unsigned_integer<T: Iterator<Item = char>>(input: T) -> Result<u32, ()> {
+ do_parse_integer(input).and_then(|result| result.to_u32().ok_or(()))
+}
+
+/// Parse a floating-point number according to
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-floating-point-number-values>
+pub fn parse_double(string: &str) -> Result<f64, ()> {
+ let trimmed = string.trim_matches(HTML_SPACE_CHARACTERS);
+ let mut input = trimmed.chars().peekable();
+
+ let (value, divisor, chars_skipped) = match input.peek() {
+ None => return Err(()),
+ Some(&'-') => {
+ input.next();
+ (-1f64, -1f64, 1)
+ },
+ Some(&'+') => {
+ input.next();
+ (1f64, 1f64, 1)
+ },
+ _ => (1f64, 1f64, 0),
+ };
+
+ let (value, value_digits) = if let Some(&'.') = input.peek() {
+ (0f64, 0)
+ } else {
+ let (read_val, read_digits) = read_numbers(input);
+ (
+ value * read_val.and_then(|result| result.to_f64()).unwrap_or(1f64),
+ read_digits,
+ )
+ };
+
+ let input = trimmed
+ .chars()
+ .skip(value_digits + chars_skipped)
+ .peekable();
+
+ let (mut value, fraction_digits) = read_fraction(input, divisor, value);
+
+ let input = trimmed
+ .chars()
+ .skip(value_digits + chars_skipped + fraction_digits)
+ .peekable();
+
+ if let Some(exp) = read_exponent(input) {
+ value *= 10f64.powi(exp)
+ };
+
+ Ok(value)
+}
+
+impl AttrValue {
+ pub fn from_serialized_tokenlist(tokens: String) -> AttrValue {
+ let atoms =
+ split_html_space_chars(&tokens)
+ .map(Atom::from)
+ .fold(vec![], |mut acc, atom| {
+ if !acc.contains(&atom) {
+ acc.push(atom)
+ }
+ acc
+ });
+ AttrValue::TokenList(tokens, atoms)
+ }
+
+ pub fn from_comma_separated_tokenlist(tokens: String) -> AttrValue {
+ let atoms = split_commas(&tokens)
+ .map(Atom::from)
+ .fold(vec![], |mut acc, atom| {
+ if !acc.contains(&atom) {
+ acc.push(atom)
+ }
+ acc
+ });
+ AttrValue::TokenList(tokens, atoms)
+ }
+
+ pub fn from_atomic_tokens(atoms: Vec<Atom>) -> AttrValue {
+ // TODO(ajeffrey): effecient conversion of Vec<Atom> to String
+ let tokens = String::from(str_join(&atoms, "\x20"));
+ AttrValue::TokenList(tokens, atoms)
+ }
+
+ // https://html.spec.whatwg.org/multipage/#reflecting-content-attributes-in-idl-attributes:idl-unsigned-long
+ pub fn from_u32(string: String, default: u32) -> AttrValue {
+ let result = parse_unsigned_integer(string.chars()).unwrap_or(default);
+ let result = if result > UNSIGNED_LONG_MAX {
+ default
+ } else {
+ result
+ };
+ AttrValue::UInt(string, result)
+ }
+
+ pub fn from_i32(string: String, default: i32) -> AttrValue {
+ let result = parse_integer(string.chars()).unwrap_or(default);
+ AttrValue::Int(string, result)
+ }
+
+ // https://html.spec.whatwg.org/multipage/#reflecting-content-attributes-in-idl-attributes:idl-double
+ pub fn from_double(string: String, default: f64) -> AttrValue {
+ let result = parse_double(&string).unwrap_or(default);
+
+ if result.is_normal() {
+ AttrValue::Double(string, result)
+ } else {
+ AttrValue::Double(string, default)
+ }
+ }
+
+ // https://html.spec.whatwg.org/multipage/#limited-to-only-non-negative-numbers
+ pub fn from_limited_i32(string: String, default: i32) -> AttrValue {
+ let result = parse_integer(string.chars()).unwrap_or(default);
+
+ if result < 0 {
+ AttrValue::Int(string, default)
+ } else {
+ AttrValue::Int(string, result)
+ }
+ }
+
+ // https://html.spec.whatwg.org/multipage/#limited-to-only-non-negative-numbers-greater-than-zero
+ pub fn from_limited_u32(string: String, default: u32) -> AttrValue {
+ let result = parse_unsigned_integer(string.chars()).unwrap_or(default);
+ let result = if result == 0 || result > UNSIGNED_LONG_MAX {
+ default
+ } else {
+ result
+ };
+ AttrValue::UInt(string, result)
+ }
+
+ pub fn from_atomic(string: String) -> AttrValue {
+ let value = Atom::from(string);
+ AttrValue::Atom(value)
+ }
+
+ pub fn from_resolved_url(base: &ServoUrl, url: String) -> AttrValue {
+ let joined = base.join(&url).ok();
+ AttrValue::ResolvedUrl(url, joined)
+ }
+
+ pub fn from_legacy_color(string: String) -> AttrValue {
+ let parsed = parse_legacy_color(&string).ok();
+ AttrValue::Color(string, parsed)
+ }
+
+ pub fn from_dimension(string: String) -> AttrValue {
+ let parsed = parse_length(&string);
+ AttrValue::Dimension(string, parsed)
+ }
+
+ pub fn from_nonzero_dimension(string: String) -> AttrValue {
+ let parsed = parse_nonzero_length(&string);
+ AttrValue::Dimension(string, parsed)
+ }
+
+ /// Assumes the `AttrValue` is a `TokenList` and returns its tokens
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `TokenList`
+ pub fn as_tokens(&self) -> &[Atom] {
+ match *self {
+ AttrValue::TokenList(_, ref tokens) => tokens,
+ _ => panic!("Tokens not found"),
+ }
+ }
+
+ /// Assumes the `AttrValue` is an `Atom` and returns its value
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not an `Atom`
+ pub fn as_atom(&self) -> &Atom {
+ match *self {
+ AttrValue::Atom(ref value) => value,
+ _ => panic!("Atom not found"),
+ }
+ }
+
+ /// Assumes the `AttrValue` is a `Color` and returns its value
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `Color`
+ pub fn as_color(&self) -> Option<&RGBA> {
+ match *self {
+ AttrValue::Color(_, ref color) => color.as_ref(),
+ _ => panic!("Color not found"),
+ }
+ }
+
+ /// Assumes the `AttrValue` is a `Dimension` and returns its value
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `Dimension`
+ pub fn as_dimension(&self) -> &LengthOrPercentageOrAuto {
+ match *self {
+ AttrValue::Dimension(_, ref l) => l,
+ _ => panic!("Dimension not found"),
+ }
+ }
+
+ /// Assumes the `AttrValue` is a `ResolvedUrl` and returns its value.
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `ResolvedUrl`
+ pub fn as_resolved_url(&self) -> Option<&ServoUrl> {
+ match *self {
+ AttrValue::ResolvedUrl(_, ref url) => url.as_ref(),
+ _ => panic!("Url not found"),
+ }
+ }
+
+ /// Return the AttrValue as its integer representation, if any.
+ /// This corresponds to attribute values returned as `AttrValue::UInt(_)`
+ /// by `VirtualMethods::parse_plain_attribute()`.
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `UInt`
+ pub fn as_uint(&self) -> u32 {
+ if let AttrValue::UInt(_, value) = *self {
+ value
+ } else {
+ panic!("Uint not found");
+ }
+ }
+
+ /// Return the AttrValue as a dimension computed from its integer
+ /// representation, assuming that integer representation specifies pixels.
+ ///
+ /// This corresponds to attribute values returned as `AttrValue::UInt(_)`
+ /// by `VirtualMethods::parse_plain_attribute()`.
+ ///
+ /// ## Panics
+ ///
+ /// Panics if the `AttrValue` is not a `UInt`
+ pub fn as_uint_px_dimension(&self) -> LengthOrPercentageOrAuto {
+ if let AttrValue::UInt(_, value) = *self {
+ LengthOrPercentageOrAuto::Length(Au::from_px(value as i32))
+ } else {
+ panic!("Uint not found");
+ }
+ }
+
+ pub fn eval_selector(&self, selector: &AttrSelectorOperation<&AtomString>) -> bool {
+ // FIXME(SimonSapin) this can be more efficient by matching on `(self, selector)` variants
+ // and doing Atom comparisons instead of string comparisons where possible,
+ // with SelectorImpl::AttrValue changed to Atom.
+ selector.eval_str(self)
+ }
+}
+
+impl ::std::ops::Deref for AttrValue {
+ type Target = str;
+
+ fn deref(&self) -> &str {
+ match *self {
+ AttrValue::String(ref value) |
+ AttrValue::TokenList(ref value, _) |
+ AttrValue::UInt(ref value, _) |
+ AttrValue::Double(ref value, _) |
+ AttrValue::Length(ref value, _) |
+ AttrValue::Color(ref value, _) |
+ AttrValue::Int(ref value, _) |
+ AttrValue::ResolvedUrl(ref value, _) |
+ AttrValue::Declaration(ref value, _) |
+ AttrValue::Dimension(ref value, _) => &value,
+ AttrValue::Atom(ref value) => &value,
+ }
+ }
+}
+
+impl PartialEq<Atom> for AttrValue {
+ fn eq(&self, other: &Atom) -> bool {
+ match *self {
+ AttrValue::Atom(ref value) => value == other,
+ _ => other == &**self,
+ }
+ }
+}
+
+/// <https://html.spec.whatwg.org/multipage/#rules-for-parsing-non-zero-dimension-values>
+pub fn parse_nonzero_length(value: &str) -> LengthOrPercentageOrAuto {
+ match parse_length(value) {
+ LengthOrPercentageOrAuto::Length(x) if x == Au::zero() => LengthOrPercentageOrAuto::Auto,
+ LengthOrPercentageOrAuto::Percentage(x) if x == 0. => LengthOrPercentageOrAuto::Auto,
+ x => x,
+ }
+}
+
+/// Parses a [legacy color][color]. If unparseable, `Err` is returned.
+///
+/// [color]: https://html.spec.whatwg.org/multipage/#rules-for-parsing-a-legacy-colour-value
+pub fn parse_legacy_color(mut input: &str) -> Result<RGBA, ()> {
+ // Steps 1 and 2.
+ if input.is_empty() {
+ return Err(());
+ }
+
+ // Step 3.
+ input = input.trim_matches(HTML_SPACE_CHARACTERS);
+
+ // Step 4.
+ if input.eq_ignore_ascii_case("transparent") {
+ return Err(());
+ }
+
+ // Step 5.
+ if let Ok(Color::RGBA(rgba)) = cssparser::parse_color_keyword(input) {
+ return Ok(rgba);
+ }
+
+ // Step 6.
+ if input.len() == 4 {
+ if let (b'#', Ok(r), Ok(g), Ok(b)) = (
+ input.as_bytes()[0],
+ hex(input.as_bytes()[1] as char),
+ hex(input.as_bytes()[2] as char),
+ hex(input.as_bytes()[3] as char),
+ ) {
+ return Ok(RGBA::new(r * 17, g * 17, b * 17, 255));
+ }
+ }
+
+ // Step 7.
+ let mut new_input = String::new();
+ for ch in input.chars() {
+ if ch as u32 > 0xffff {
+ new_input.push_str("00")
+ } else {
+ new_input.push(ch)
+ }
+ }
+ let mut input = &*new_input;
+
+ // Step 8.
+ for (char_count, (index, _)) in input.char_indices().enumerate() {
+ if char_count == 128 {
+ input = &input[..index];
+ break;
+ }
+ }
+
+ // Step 9.
+ if input.as_bytes()[0] == b'#' {
+ input = &input[1..]
+ }
+
+ // Step 10.
+ let mut new_input = Vec::new();
+ for ch in input.chars() {
+ if hex(ch).is_ok() {
+ new_input.push(ch as u8)
+ } else {
+ new_input.push(b'0')
+ }
+ }
+ let mut input = new_input;
+
+ // Step 11.
+ while input.is_empty() || (input.len() % 3) != 0 {
+ input.push(b'0')
+ }
+
+ // Step 12.
+ let mut length = input.len() / 3;
+ let (mut red, mut green, mut blue) = (
+ &input[..length],
+ &input[length..length * 2],
+ &input[length * 2..],
+ );
+
+ // Step 13.
+ if length > 8 {
+ red = &red[length - 8..];
+ green = &green[length - 8..];
+ blue = &blue[length - 8..];
+ length = 8
+ }
+
+ // Step 14.
+ while length > 2 && red[0] == b'0' && green[0] == b'0' && blue[0] == b'0' {
+ red = &red[1..];
+ green = &green[1..];
+ blue = &blue[1..];
+ length -= 1
+ }
+
+ // Steps 15-20.
+ return Ok(RGBA::new(
+ hex_string(red).unwrap(),
+ hex_string(green).unwrap(),
+ hex_string(blue).unwrap(),
+ 255,
+ ));
+
+ fn hex(ch: char) -> Result<u8, ()> {
+ match ch {
+ '0'..='9' => Ok((ch as u8) - b'0'),
+ 'a'..='f' => Ok((ch as u8) - b'a' + 10),
+ 'A'..='F' => Ok((ch as u8) - b'A' + 10),
+ _ => Err(()),
+ }
+ }
+
+ fn hex_string(string: &[u8]) -> Result<u8, ()> {
+ match string.len() {
+ 0 => Err(()),
+ 1 => hex(string[0] as char),
+ _ => {
+ let upper = hex(string[0] as char)?;
+ let lower = hex(string[1] as char)?;
+ Ok((upper << 4) | lower)
+ },
+ }
+ }
+}
+
+/// Parses a [dimension value][dim]. If unparseable, `Auto` is returned.
+///
+/// [dim]: https://html.spec.whatwg.org/multipage/#rules-for-parsing-dimension-values
+// TODO: this function can be rewritten to return Result<LengthPercentage, _>
+pub fn parse_length(mut value: &str) -> LengthOrPercentageOrAuto {
+ // Steps 1 & 2 are not relevant
+
+ // Step 3
+ value = value.trim_start_matches(HTML_SPACE_CHARACTERS);
+
+ // Step 4
+ match value.chars().nth(0) {
+ Some('0'..='9') => {},
+ _ => return LengthOrPercentageOrAuto::Auto,
+ }
+
+ // Steps 5 to 8
+ // We trim the string length to the minimum of:
+ // 1. the end of the string
+ // 2. the first occurence of a '%' (U+0025 PERCENT SIGN)
+ // 3. the second occurrence of a '.' (U+002E FULL STOP)
+ // 4. the occurrence of a character that is neither a digit nor '%' nor '.'
+ // Note: Step 7.4 is directly subsumed by FromStr::from_str
+ let mut end_index = value.len();
+ let (mut found_full_stop, mut found_percent) = (false, false);
+ for (i, ch) in value.chars().enumerate() {
+ match ch {
+ '0'..='9' => continue,
+ '%' => {
+ found_percent = true;
+ end_index = i;
+ break;
+ },
+ '.' if !found_full_stop => {
+ found_full_stop = true;
+ continue;
+ },
+ _ => {
+ end_index = i;
+ break;
+ },
+ }
+ }
+ value = &value[..end_index];
+
+ if found_percent {
+ let result: Result<f32, _> = FromStr::from_str(value);
+ match result {
+ Ok(number) => return LengthOrPercentageOrAuto::Percentage((number as f32) / 100.0),
+ Err(_) => return LengthOrPercentageOrAuto::Auto,
+ }
+ }
+
+ match FromStr::from_str(value) {
+ Ok(number) => LengthOrPercentageOrAuto::Length(Au::from_f64_px(number)),
+ Err(_) => LengthOrPercentageOrAuto::Auto,
+ }
+}
+
+/// A struct that uniquely identifies an element's attribute.
+#[derive(Clone, Debug)]
+#[cfg_attr(feature = "servo", derive(MallocSizeOf))]
+pub struct AttrIdentifier {
+ pub local_name: LocalName,
+ pub name: LocalName,
+ pub namespace: Namespace,
+ pub prefix: Option<Prefix>,
+}
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