style: [css-properties-values-api] Parsing and serialization for @property syntax descriptor

Based off of @emilio's syntax parser at
<https://github.com/emilio/css-typed-om-syntax>.

Co-authored-by: Emilio Cobos Álvarez <emilio@crisal.io>

Differential Revision: https://phabricator.services.mozilla.com/D178268
This commit is contained in:
Zach Hoffman 2023-05-22 05:14:13 +00:00 committed by Martin Robinson
parent 8823b63513
commit 87ce7045ef
13 changed files with 522 additions and 14 deletions

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@ -45,7 +45,7 @@ fn rgb_to_hue_min_max(red: f32, green: f32, blue: f32) -> (f32, f32, f32) {
(red - green) / delta + 4.0
}
} else {
std::f32::NAN
f32::NAN
};
(hue, min, max)

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@ -107,6 +107,7 @@ pub mod media_queries;
pub mod parallel;
pub mod parser;
pub mod piecewise_linear;
pub mod properties_and_values;
#[macro_use]
pub mod queries;
pub mod rule_cache;

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@ -0,0 +1,9 @@
/* 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/. */
//! Properties and Values
//!
//! https://drafts.css-houdini.org/css-properties-values-api-1/
pub mod syntax;

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@ -0,0 +1,60 @@
/* 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/. */
/// Trims ASCII whitespace characters from a slice, and returns the trimmed input.
pub fn trim_ascii_whitespace(input: &str) -> &str {
if input.is_empty() {
return input;
}
let mut start = 0;
{
let mut iter = input.as_bytes().iter();
loop {
let byte = match iter.next() {
Some(b) => b,
None => return "",
};
if !byte.is_ascii_whitespace() {
break;
}
start += 1;
}
}
let mut end = input.len();
assert!(start < end);
{
let mut iter = input.as_bytes()[start..].iter().rev();
loop {
let byte = match iter.next() {
Some(b) => b,
None => {
debug_assert!(false, "We should have caught this in the loop above!");
return "";
},
};
if !byte.is_ascii_whitespace() {
break;
}
end -= 1;
}
}
&input[start..end]
}
#[test]
fn trim_ascii_whitespace_test() {
fn test(i: &str, o: &str) {
assert_eq!(trim_ascii_whitespace(i), o)
}
test("", "");
test(" ", "");
test(" a b c ", "a b c");
test(" \t \t \ta b c \t \t \t \t", "a b c");
}

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@ -0,0 +1,91 @@
/* 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/. */
use super::{Component, ComponentName, Multiplier};
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#supported-names>
#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
pub enum DataType {
/// Any valid `<length>` value
Length,
/// `<number>` values
Number,
/// Any valid <percentage> value
Percentage,
/// Any valid `<length>` or `<percentage>` value, any valid `<calc()>` expression combining
/// `<length>` and `<percentage>` components.
LengthPercentage,
/// Any valid `<color>` value
Color,
/// Any valid `<image>` value
Image,
/// Any valid `<url>` value
Url,
/// Any valid `<integer>` value
Integer,
/// Any valid `<angle>` value
Angle,
/// Any valid `<time>` value
Time,
/// Any valid `<resolution>` value
Resolution,
/// Any valid `<transform-function>` value
TransformFunction,
/// A list of valid `<transform-function>` values. Note that "<transform-list>" is a pre-multiplied
/// data type name equivalent to "<transform-function>+"
TransformList,
/// Any valid `<custom-ident>` value
CustomIdent,
}
impl DataType {
pub fn unpremultiply(&self) -> Option<Component> {
match *self {
DataType::TransformList => Some(Component {
name: ComponentName::DataType(DataType::TransformFunction),
multiplier: Some(Multiplier::Space),
}),
_ => None,
}
}
pub fn from_str(ty: &str) -> Option<Self> {
Some(match ty.as_bytes() {
b"length" => DataType::Length,
b"number" => DataType::Number,
b"percentage" => DataType::Percentage,
b"length-percentage" => DataType::LengthPercentage,
b"color" => DataType::Color,
b"image" => DataType::Image,
b"url" => DataType::Url,
b"integer" => DataType::Integer,
b"angle" => DataType::Angle,
b"time" => DataType::Time,
b"resolution" => DataType::Resolution,
b"transform-function" => DataType::TransformFunction,
b"custom-ident" => DataType::CustomIdent,
b"transform-list" => DataType::TransformList,
_ => return None,
})
}
pub fn to_str(&self) -> &str {
match self {
DataType::Length => "length",
DataType::Number => "number",
DataType::Percentage => "percentage",
DataType::LengthPercentage => "length-percentage",
DataType::Color => "color",
DataType::Image => "image",
DataType::Url => "url",
DataType::Integer => "integer",
DataType::Angle => "angle",
DataType::Time => "time",
DataType::Resolution => "resolution",
DataType::TransformFunction => "transform-function",
DataType::CustomIdent => "custom-ident",
DataType::TransformList => "transform-list",
}
}
}

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@ -0,0 +1,328 @@
/* 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/. */
//! Used for parsing and serializing the [`@property`] syntax string.
//!
//! <https://drafts.css-houdini.org/css-properties-values-api-1/#parsing-syntax>
use std::fmt::{self, Debug};
use std::{borrow::Cow, fmt::Write};
use crate::parser::{Parse, ParserContext};
use crate::values::CustomIdent;
use cssparser::{Parser as CSSParser, ParserInput as CSSParserInput};
use style_traits::{
CssWriter, ParseError as StyleParseError, PropertySyntaxParseError as ParseError,
StyleParseErrorKind, ToCss,
};
use self::data_type::DataType;
mod ascii;
mod data_type;
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#parsing-syntax>
#[derive(Debug, Clone, MallocSizeOf)]
pub struct Descriptor {
components: Box<[Component]>,
css: String,
}
impl Descriptor {
/// Returns the universal syntax definition with the given CSS representation.
fn universal(css: &str) -> Self {
Self {
components: Default::default(),
css: String::from(css),
}
}
/// Returns the specified syntax string.
pub fn as_str(&self) -> &str {
&self.css
}
}
impl PartialEq for Descriptor {
fn eq(&self, other: &Self) -> bool {
self.components == other.components
}
}
impl Parse for Descriptor {
/// Parse a syntax descriptor.
fn parse<'i, 't>(
_context: &ParserContext,
parser: &mut CSSParser<'i, 't>,
) -> Result<Self, StyleParseError<'i>> {
// 1. Strip leading and trailing ASCII whitespace from string.
let input = parser.expect_string()?;
match parse_descriptor(input) {
Ok(syntax) => Ok(syntax),
Err(err) => Err(parser.new_custom_error(StyleParseErrorKind::PropertySyntaxField(err))),
}
}
}
impl ToCss for Descriptor {
fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
where
W: Write,
{
self.css.to_css(dest)
}
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#multipliers>
#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq)]
pub enum Multiplier {
/// Indicates a space-separated list.
Space,
/// Indicates a comma-separated list.
Comma,
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#syntax-component>
#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
pub struct Component {
name: ComponentName,
multiplier: Option<Multiplier>,
}
impl Component {
/// Returns the component's name.
#[inline]
pub fn name(&self) -> &ComponentName {
&self.name
}
/// Returns the component's multiplier, if one exists.
#[inline]
pub fn multiplier(&self) -> Option<Multiplier> {
self.multiplier
}
/// If the component is premultiplied, return the un-premultiplied component.
#[inline]
pub fn unpremultiplied(&self) -> Cow<Self> {
match self.name.unpremultiply() {
Some(component) => {
debug_assert!(
self.multiplier.is_none(),
"Shouldn't have parsed a multiplier for a pre-multiplied data type name",
);
Cow::Owned(component)
},
None => Cow::Borrowed(self),
}
}
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#syntax-component-name>
#[derive(Clone, Debug, MallocSizeOf, PartialEq)]
pub enum ComponentName {
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#data-type-name>
DataType(DataType),
/// <https://drafts.csswg.org/css-values-4/#custom-idents>
Ident(CustomIdent),
}
impl ComponentName {
fn unpremultiply(&self) -> Option<Component> {
match *self {
ComponentName::DataType(ref t) => t.unpremultiply(),
ComponentName::Ident(..) => None,
}
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#pre-multiplied-data-type-name>
fn is_pre_multiplied(&self) -> bool {
self.unpremultiply().is_some()
}
}
/// Parse a syntax descriptor.
#[inline]
fn parse_descriptor(css: &str) -> Result<Descriptor, ParseError> {
// 1. Strip leading and trailing ASCII whitespace from string.
let input = ascii::trim_ascii_whitespace(css);
// 2. If string's length is 0, return failure.
if input.is_empty() {
return Err(ParseError::EmptyInput);
}
// 3. If string's length is 1, and the only code point in string is U+002A
// ASTERISK (*), return the universal syntax descriptor.
if input.len() == 1 && input.as_bytes()[0] == b'*' {
return Ok(Descriptor::universal(css));
}
// 4. Let stream be an input stream created from the code points of string,
// preprocessed as specified in [css-syntax-3]. Let descriptor be an
// initially empty list of syntax components.
//
// NOTE(emilio): Instead of preprocessing we cheat and treat new-lines and
// nulls in the parser specially.
let mut components = vec![];
{
let mut parser = Parser::new(input, &mut components);
// 5. Repeatedly consume the next input code point from stream.
parser.parse()?;
}
Ok(Descriptor {
components: components.into_boxed_slice(),
css: String::from(css),
})
}
struct Parser<'a> {
input: &'a str,
position: usize,
output: &'a mut Vec<Component>,
}
/// <https://drafts.csswg.org/css-syntax-3/#whitespace>
fn is_whitespace(byte: u8) -> bool {
match byte {
b'\t' | b'\n' | b'\r' | b' ' => true,
_ => false,
}
}
/// <https://drafts.csswg.org/css-syntax-3/#letter>
fn is_letter(byte: u8) -> bool {
match byte {
b'A'..=b'Z' | b'a'..=b'z' => true,
_ => false,
}
}
/// <https://drafts.csswg.org/css-syntax-3/#non-ascii-code-point>
fn is_non_ascii(byte: u8) -> bool {
byte >= 0x80
}
/// <https://drafts.csswg.org/css-syntax-3/#name-start-code-point>
fn is_name_start(byte: u8) -> bool {
is_letter(byte) || is_non_ascii(byte) || byte == b'_'
}
impl<'a> Parser<'a> {
fn new(input: &'a str, output: &'a mut Vec<Component>) -> Self {
Self {
input,
position: 0,
output,
}
}
fn peek(&self) -> Option<u8> {
self.input.as_bytes().get(self.position).cloned()
}
fn parse(&mut self) -> Result<(), ParseError> {
// 5. Repeatedly consume the next input code point from stream:
loop {
let component = self.parse_component()?;
self.output.push(component);
self.skip_whitespace();
let byte = match self.peek() {
None => return Ok(()),
Some(b) => b,
};
if byte != b'|' {
return Err(ParseError::ExpectedPipeBetweenComponents);
}
self.position += 1;
}
}
fn skip_whitespace(&mut self) {
loop {
match self.peek() {
Some(c) if is_whitespace(c) => self.position += 1,
_ => return,
}
}
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#consume-data-type-name>
fn parse_data_type_name(&mut self) -> Result<DataType, ParseError> {
let start = self.position;
loop {
let byte = match self.peek() {
Some(b) => b,
None => return Err(ParseError::UnclosedDataTypeName),
};
if byte != b'>' {
self.position += 1;
continue;
}
let ty = match DataType::from_str(&self.input[start..self.position]) {
Some(ty) => ty,
None => return Err(ParseError::UnknownDataTypeName),
};
self.position += 1;
return Ok(ty);
}
}
fn parse_name(&mut self) -> Result<ComponentName, ParseError> {
let b = match self.peek() {
Some(b) => b,
None => return Err(ParseError::UnexpectedEOF),
};
if b == b'<' {
self.position += 1;
return Ok(ComponentName::DataType(self.parse_data_type_name()?));
}
if b != b'\\' && !is_name_start(b) {
return Err(ParseError::InvalidNameStart);
}
let input = &self.input[self.position..];
let mut input = CSSParserInput::new(input);
let mut input = CSSParser::new(&mut input);
let location = input.current_source_location();
let name = input
.expect_ident()
.ok()
.and_then(|name| CustomIdent::from_ident(location, name, &[]).ok());
let name = match name {
Some(name) => name,
None => return Err(ParseError::InvalidName),
};
self.position += input.position().byte_index();
return Ok(ComponentName::Ident(name));
}
fn parse_multiplier(&mut self) -> Option<Multiplier> {
let multiplier = match self.peek()? {
b'+' => Multiplier::Space,
b'#' => Multiplier::Comma,
_ => return None,
};
self.position += 1;
Some(multiplier)
}
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#consume-a-syntax-component>
fn parse_component(&mut self) -> Result<Component, ParseError> {
// Consume as much whitespace as possible from stream.
self.skip_whitespace();
let name = self.parse_name()?;
let multiplier = if name.is_pre_multiplied() {
None
} else {
self.parse_multiplier()
};
Ok(Component { name, multiplier })
}
}

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@ -197,8 +197,6 @@ impl Animate for i32 {
impl Animate for f32 {
#[inline]
fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
use std::f32;
let ret = (*self as f64).animate(&(*other as f64), procedure)?;
Ok(ret.min(f32::MAX as f64).max(f32::MIN as f64) as f32)
}
@ -208,8 +206,6 @@ impl Animate for f32 {
impl Animate for f64 {
#[inline]
fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
use std::f64;
let (self_weight, other_weight) = procedure.weights();
let ret = *self * self_weight + *other * other_weight;

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@ -383,8 +383,6 @@ impl Quaternion {
impl Animate for Quaternion {
fn animate(&self, other: &Self, procedure: Procedure) -> Result<Self, ()> {
use std::f64;
let (this_weight, other_weight) = procedure.weights();
debug_assert!(
// Doule EPSILON since both this_weight and other_weght have calculation errors

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@ -26,7 +26,7 @@ impl ToComputedValue for specified::AnimationIterationCount {
fn to_computed_value(&self, context: &Context) -> Self::ComputedValue {
AnimationIterationCount(match *self {
specified::AnimationIterationCount::Number(n) => n.to_computed_value(context).0,
specified::AnimationIterationCount::Infinite => std::f32::INFINITY,
specified::AnimationIterationCount::Infinite => f32::INFINITY,
})
}

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@ -168,7 +168,7 @@ impl<L> GenericPerspectiveFunction<L> {
/// Returns `f32::INFINITY` or the result of a function on the length value.
pub fn infinity_or(&self, f: impl FnOnce(&L) -> f32) -> f32 {
match *self {
Self::None => std::f32::INFINITY,
Self::None => f32::INFINITY,
Self::Length(ref l) => f(l),
}
}
@ -471,7 +471,6 @@ where
reference_box: Option<&Rect<ComputedLength>>,
) -> Result<Transform3D<f64>, ()> {
use self::TransformOperation::*;
use std::f64;
let reference_width = reference_box.map(|v| v.size.width);
let reference_height = reference_box.map(|v| v.size.height);
@ -501,7 +500,7 @@ where
},
Perspective(ref p) => {
let px = match p {
PerspectiveFunction::None => std::f32::INFINITY,
PerspectiveFunction::None => f32::INFINITY,
PerspectiveFunction::Length(ref p) => p.to_pixel_length(None)?,
};
create_perspective_matrix(px).cast()

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@ -20,7 +20,6 @@ use crate::values::serialize_atom_identifier;
use crate::values::specified::calc::CalcNode;
use crate::{Atom, Namespace, One, Prefix, Zero};
use cssparser::{Parser, Token};
use std::f32;
use std::fmt::{self, Write};
use std::ops::Add;
use style_traits::values::specified::AllowedNumericType;

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@ -996,8 +996,8 @@ fn parse_number(iter: &mut Peekable<Cloned<slice::Iter<u8>>>) -> Result<CSSFloat
if value.is_finite() {
Ok(value
.min(::std::f32::MAX as f64)
.max(::std::f32::MIN as f64) as CSSFloat)
.min(f32::MAX as f64)
.max(f32::MIN as f64) as CSSFloat)
} else {
Err(())
}

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@ -113,6 +113,8 @@ pub enum StyleParseErrorKind<'i> {
RangedExpressionWithNoValue,
/// A function was encountered that was not expected.
UnexpectedFunction(CowRcStr<'i>),
/// Error encountered parsing a @property's `syntax` descriptor
PropertySyntaxField(PropertySyntaxParseError),
/// @namespace must be before any rule but @charset and @import
UnexpectedNamespaceRule,
/// @import must be before any rule but @charset
@ -196,6 +198,31 @@ impl<'i> StyleParseErrorKind<'i> {
}
}
/// Errors that can be encountered while parsing the @property rule's syntax descriptor.
#[derive(Clone, Debug, PartialEq)]
pub enum PropertySyntaxParseError {
/// The string's length was 0.
EmptyInput,
/// A non-whitespace, non-pipe character was fount after parsing a component.
ExpectedPipeBetweenComponents,
/// The start of an identifier was expected but not found.
///
/// <https://drafts.csswg.org/css-syntax-3/#name-start-code-point>
InvalidNameStart,
/// The name is not a valid `<ident>`.
InvalidName,
/// The data type name was not closed.
///
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#consume-data-type-name>
UnclosedDataTypeName,
/// The next byte was expected while parsing, but EOF was found instead.
UnexpectedEOF,
/// The data type is not a supported syntax component name.
///
/// <https://drafts.css-houdini.org/css-properties-values-api-1/#supported-names>
UnknownDataTypeName,
}
bitflags! {
/// The mode to use when parsing values.
pub struct ParsingMode: u8 {