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Diffstat (limited to 'servo/components/style/values/specified/calc.rs')
| -rw-r--r-- | servo/components/style/values/specified/calc.rs | 1043 |
1 files changed, 1043 insertions, 0 deletions
diff --git a/servo/components/style/values/specified/calc.rs b/servo/components/style/values/specified/calc.rs new file mode 100644 index 0000000000..7351a61069 --- /dev/null +++ b/servo/components/style/values/specified/calc.rs @@ -0,0 +1,1043 @@ +/* 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/. */ + +//! [Calc expressions][calc]. +//! +//! [calc]: https://drafts.csswg.org/css-values/#calc-notation + +use crate::parser::ParserContext; +use crate::values::generics::calc as generic; +use crate::values::generics::calc::{MinMaxOp, ModRemOp, RoundingStrategy, SortKey}; +use crate::values::specified::length::{AbsoluteLength, FontRelativeLength, NoCalcLength}; +use crate::values::specified::length::{ContainerRelativeLength, ViewportPercentageLength}; +use crate::values::specified::{self, Angle, Resolution, Time}; +use crate::values::{CSSFloat, CSSInteger}; +use cssparser::{AngleOrNumber, CowRcStr, NumberOrPercentage, Parser, Token}; +use smallvec::SmallVec; +use std::cmp; +use std::fmt::{self, Write}; +use style_traits::values::specified::AllowedNumericType; +use style_traits::{CssWriter, ParseError, SpecifiedValueInfo, StyleParseErrorKind, ToCss}; + +fn trig_enabled() -> bool { + static_prefs::pref!("layout.css.trig.enabled") +} + +fn nan_inf_enabled() -> bool { + static_prefs::pref!("layout.css.nan-inf.enabled") +} + +/// The name of the mathematical function that we're parsing. +#[derive(Clone, Copy, Debug, Parse)] +pub enum MathFunction { + /// `calc()`: https://drafts.csswg.org/css-values-4/#funcdef-calc + Calc, + /// `min()`: https://drafts.csswg.org/css-values-4/#funcdef-min + Min, + /// `max()`: https://drafts.csswg.org/css-values-4/#funcdef-max + Max, + /// `clamp()`: https://drafts.csswg.org/css-values-4/#funcdef-clamp + Clamp, + /// `round()`: https://drafts.csswg.org/css-values-4/#funcdef-round + Round, + /// `mod()`: https://drafts.csswg.org/css-values-4/#funcdef-mod + Mod, + /// `rem()`: https://drafts.csswg.org/css-values-4/#funcdef-rem + Rem, + /// `sin()`: https://drafts.csswg.org/css-values-4/#funcdef-sin + Sin, + /// `cos()`: https://drafts.csswg.org/css-values-4/#funcdef-cos + Cos, + /// `tan()`: https://drafts.csswg.org/css-values-4/#funcdef-tan + Tan, + /// `asin()`: https://drafts.csswg.org/css-values-4/#funcdef-asin + Asin, + /// `acos()`: https://drafts.csswg.org/css-values-4/#funcdef-acos + Acos, + /// `atan()`: https://drafts.csswg.org/css-values-4/#funcdef-atan + Atan, + /// `atan2()`: https://drafts.csswg.org/css-values-4/#funcdef-atan2 + Atan2, + /// `pow()`: https://drafts.csswg.org/css-values-4/#funcdef-pow + Pow, + /// `sqrt()`: https://drafts.csswg.org/css-values-4/#funcdef-sqrt + Sqrt, + /// `hypot()`: https://drafts.csswg.org/css-values-4/#funcdef-hypot + Hypot, + /// `log()`: https://drafts.csswg.org/css-values-4/#funcdef-log + Log, + /// `exp()`: https://drafts.csswg.org/css-values-4/#funcdef-exp + Exp, +} + +/// A leaf node inside a `Calc` expression's AST. +#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToShmem)] +pub enum Leaf { + /// `<length>` + Length(NoCalcLength), + /// `<angle>` + Angle(Angle), + /// `<time>` + Time(Time), + /// `<resolution>` + Resolution(Resolution), + /// `<percentage>` + Percentage(CSSFloat), + /// `<number>` + Number(CSSFloat), +} + +impl Leaf { + fn as_length(&self) -> Option<&NoCalcLength> { + match *self { + Self::Length(ref l) => Some(l), + _ => None, + } + } +} + +impl ToCss for Leaf { + fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result + where + W: Write, + { + match *self { + Self::Length(ref l) => l.to_css(dest), + Self::Number(ref n) => n.to_css(dest), + Self::Resolution(ref r) => r.to_css(dest), + Self::Percentage(p) => crate::values::serialize_percentage(p, dest), + Self::Angle(ref a) => a.to_css(dest), + Self::Time(ref t) => t.to_css(dest), + } + } +} + +bitflags! { + /// Expected units we allow parsing within a `calc()` expression. + /// + /// This is used as a hint for the parser to fast-reject invalid + /// expressions. Numbers are always allowed because they multiply other + /// units. + #[derive(Clone, Copy)] + struct CalcUnits: u8 { + const LENGTH = 1 << 0; + const PERCENTAGE = 1 << 1; + const ANGLE = 1 << 2; + const TIME = 1 << 3; + const RESOLUTION = 1 << 3; + + const LENGTH_PERCENTAGE = Self::LENGTH.bits | Self::PERCENTAGE.bits; + // NOTE: When you add to this, make sure to make Atan2 deal with these. + const ALL = Self::LENGTH.bits | Self::PERCENTAGE.bits | Self::ANGLE.bits | Self::TIME.bits | Self::RESOLUTION.bits; + } +} + +/// A struct to hold a simplified `<length>` or `<percentage>` expression. +/// +/// In some cases, e.g. DOMMatrix, we support calc(), but reject all the +/// relative lengths, and to_computed_pixel_length_without_context() handles +/// this case. Therefore, if you want to add a new field, please make sure this +/// function work properly. +#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToCss, ToShmem)] +#[allow(missing_docs)] +pub struct CalcLengthPercentage { + #[css(skip)] + pub clamping_mode: AllowedNumericType, + pub node: CalcNode, +} + +impl CalcLengthPercentage { + fn same_unit_length_as(a: &Self, b: &Self) -> Option<(CSSFloat, CSSFloat)> { + use generic::CalcNodeLeaf; + + debug_assert_eq!(a.clamping_mode, b.clamping_mode); + debug_assert_eq!(a.clamping_mode, AllowedNumericType::All); + + let a = a.node.as_leaf()?; + let b = b.node.as_leaf()?; + + if a.sort_key() != b.sort_key() { + return None; + } + + let a = a.as_length()?.unitless_value(); + let b = b.as_length()?.unitless_value(); + return Some((a, b)); + } +} + +impl SpecifiedValueInfo for CalcLengthPercentage {} + +impl PartialOrd for Leaf { + fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> { + use self::Leaf::*; + + if std::mem::discriminant(self) != std::mem::discriminant(other) { + return None; + } + + match (self, other) { + // NOTE: Percentages can't be compared reasonably here because the + // percentage basis might be negative, see bug 1709018. + // Conveniently, we only use this for <length-percentage> (for raw + // percentages, we go through resolve()). + (&Percentage(..), &Percentage(..)) => None, + (&Length(ref one), &Length(ref other)) => one.partial_cmp(other), + (&Angle(ref one), &Angle(ref other)) => one.degrees().partial_cmp(&other.degrees()), + (&Time(ref one), &Time(ref other)) => one.seconds().partial_cmp(&other.seconds()), + (&Resolution(ref one), &Resolution(ref other)) => one.dppx().partial_cmp(&other.dppx()), + (&Number(ref one), &Number(ref other)) => one.partial_cmp(other), + _ => { + match *self { + Length(..) | Percentage(..) | Angle(..) | Time(..) | Number(..) | + Resolution(..) => {}, + } + unsafe { + debug_unreachable!("Forgot a branch?"); + } + }, + } + } +} + +impl generic::CalcNodeLeaf for Leaf { + fn unitless_value(&self) -> f32 { + match *self { + Self::Length(ref l) => l.unitless_value(), + Self::Percentage(n) | Self::Number(n) => n, + Self::Resolution(ref r) => r.dppx(), + Self::Angle(ref a) => a.degrees(), + Self::Time(ref t) => t.seconds(), + } + } + + fn sort_key(&self) -> SortKey { + match *self { + Self::Number(..) => SortKey::Number, + Self::Percentage(..) => SortKey::Percentage, + Self::Time(..) => SortKey::Sec, + Self::Resolution(..) => SortKey::Dppx, + Self::Angle(..) => SortKey::Deg, + Self::Length(ref l) => match *l { + NoCalcLength::Absolute(..) => SortKey::Px, + NoCalcLength::FontRelative(ref relative) => match *relative { + FontRelativeLength::Ch(..) => SortKey::Ch, + FontRelativeLength::Em(..) => SortKey::Em, + FontRelativeLength::Ex(..) => SortKey::Ex, + FontRelativeLength::Cap(..) => SortKey::Cap, + FontRelativeLength::Ic(..) => SortKey::Ic, + FontRelativeLength::Rem(..) => SortKey::Rem, + }, + NoCalcLength::ViewportPercentage(ref vp) => match *vp { + ViewportPercentageLength::Vh(..) => SortKey::Vh, + ViewportPercentageLength::Svh(..) => SortKey::Svh, + ViewportPercentageLength::Lvh(..) => SortKey::Lvh, + ViewportPercentageLength::Dvh(..) => SortKey::Dvh, + ViewportPercentageLength::Vw(..) => SortKey::Vw, + ViewportPercentageLength::Svw(..) => SortKey::Svw, + ViewportPercentageLength::Lvw(..) => SortKey::Lvw, + ViewportPercentageLength::Dvw(..) => SortKey::Dvw, + ViewportPercentageLength::Vmax(..) => SortKey::Vmax, + ViewportPercentageLength::Svmax(..) => SortKey::Svmax, + ViewportPercentageLength::Lvmax(..) => SortKey::Lvmax, + ViewportPercentageLength::Dvmax(..) => SortKey::Dvmax, + ViewportPercentageLength::Vmin(..) => SortKey::Vmin, + ViewportPercentageLength::Svmin(..) => SortKey::Svmin, + ViewportPercentageLength::Lvmin(..) => SortKey::Lvmin, + ViewportPercentageLength::Dvmin(..) => SortKey::Dvmin, + ViewportPercentageLength::Vb(..) => SortKey::Vb, + ViewportPercentageLength::Svb(..) => SortKey::Svb, + ViewportPercentageLength::Lvb(..) => SortKey::Lvb, + ViewportPercentageLength::Dvb(..) => SortKey::Dvb, + ViewportPercentageLength::Vi(..) => SortKey::Vi, + ViewportPercentageLength::Svi(..) => SortKey::Svi, + ViewportPercentageLength::Lvi(..) => SortKey::Lvi, + ViewportPercentageLength::Dvi(..) => SortKey::Dvi, + }, + NoCalcLength::ContainerRelative(ref cq) => match *cq { + ContainerRelativeLength::Cqw(..) => SortKey::Cqw, + ContainerRelativeLength::Cqh(..) => SortKey::Cqh, + ContainerRelativeLength::Cqi(..) => SortKey::Cqi, + ContainerRelativeLength::Cqb(..) => SortKey::Cqb, + ContainerRelativeLength::Cqmin(..) => SortKey::Cqmin, + ContainerRelativeLength::Cqmax(..) => SortKey::Cqmax, + }, + NoCalcLength::ServoCharacterWidth(..) => unreachable!(), + }, + } + } + + fn simplify(&mut self) { + if let Self::Length(NoCalcLength::Absolute(ref mut abs)) = *self { + *abs = AbsoluteLength::Px(abs.to_px()); + } + } + + /// Tries to merge one sum to another, that is, perform `x` + `y`. + /// + /// Only handles leaf nodes, it's the caller's responsibility to simplify + /// them before calling this if needed. + fn try_sum_in_place(&mut self, other: &Self) -> Result<(), ()> { + use self::Leaf::*; + + if std::mem::discriminant(self) != std::mem::discriminant(other) { + return Err(()); + } + + match (self, other) { + (&mut Number(ref mut one), &Number(ref other)) | + (&mut Percentage(ref mut one), &Percentage(ref other)) => { + *one += *other; + }, + (&mut Angle(ref mut one), &Angle(ref other)) => { + *one = specified::Angle::from_calc(one.degrees() + other.degrees()); + }, + (&mut Time(ref mut one), &Time(ref other)) => { + *one = specified::Time::from_seconds(one.seconds() + other.seconds()); + }, + (&mut Resolution(ref mut one), &Resolution(ref other)) => { + *one = specified::Resolution::from_dppx(one.dppx() + other.dppx()); + }, + (&mut Length(ref mut one), &Length(ref other)) => { + *one = one.try_op(other, std::ops::Add::add)?; + }, + _ => { + match *other { + Number(..) | Percentage(..) | Angle(..) | Time(..) | Resolution(..) | + Length(..) => {}, + } + unsafe { + debug_unreachable!(); + } + }, + } + + Ok(()) + } + + fn try_op<O>(&self, other: &Self, op: O) -> Result<Self, ()> + where + O: Fn(f32, f32) -> f32, + { + use self::Leaf::*; + + if std::mem::discriminant(self) != std::mem::discriminant(other) { + return Err(()); + } + + match (self, other) { + (&Number(one), &Number(other)) => { + return Ok(Leaf::Number(op(one, other))); + }, + (&Percentage(one), &Percentage(other)) => { + return Ok(Leaf::Percentage(op(one, other))); + }, + (&Angle(ref one), &Angle(ref other)) => { + return Ok(Leaf::Angle(specified::Angle::from_calc(op( + one.degrees(), + other.degrees(), + )))); + }, + (&Resolution(ref one), &Resolution(ref other)) => { + return Ok(Leaf::Resolution(specified::Resolution::from_dppx(op( + one.dppx(), + other.dppx(), + )))); + }, + (&Time(ref one), &Time(ref other)) => { + return Ok(Leaf::Time(specified::Time::from_seconds(op( + one.seconds(), + other.seconds(), + )))); + }, + (&Length(ref one), &Length(ref other)) => { + return Ok(Leaf::Length(one.try_op(other, op)?)); + }, + _ => { + match *other { + Number(..) | Percentage(..) | Angle(..) | Time(..) | Length(..) | + Resolution(..) => {}, + } + unsafe { + debug_unreachable!(); + } + }, + } + } + + fn map(&mut self, mut op: impl FnMut(f32) -> f32) { + match self { + Leaf::Length(one) => *one = one.map(op), + Leaf::Angle(one) => *one = specified::Angle::from_calc(op(one.degrees())), + Leaf::Time(one) => *one = specified::Time::from_seconds(op(one.seconds())), + Leaf::Resolution(one) => *one = specified::Resolution::from_dppx(op(one.dppx())), + Leaf::Percentage(one) => *one = op(*one), + Leaf::Number(one) => *one = op(*one), + } + } +} + +/// A calc node representation for specified values. +pub type CalcNode = generic::GenericCalcNode<Leaf>; + +impl CalcNode { + /// Tries to parse a single element in the expression, that is, a + /// `<length>`, `<angle>`, `<time>`, `<percentage>`, according to + /// `allowed_units`. + /// + /// May return a "complex" `CalcNode`, in the presence of a parenthesized + /// expression, for example. + fn parse_one<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + allowed_units: CalcUnits, + ) -> Result<Self, ParseError<'i>> { + let location = input.current_source_location(); + match input.next()? { + &Token::Number { value, .. } => Ok(CalcNode::Leaf(Leaf::Number(value))), + &Token::Dimension { + value, ref unit, .. + } => { + if allowed_units.intersects(CalcUnits::LENGTH) { + if let Ok(l) = NoCalcLength::parse_dimension(context, value, unit) { + return Ok(CalcNode::Leaf(Leaf::Length(l))); + } + } + if allowed_units.intersects(CalcUnits::ANGLE) { + if let Ok(a) = Angle::parse_dimension(value, unit, /* from_calc = */ true) { + return Ok(CalcNode::Leaf(Leaf::Angle(a))); + } + } + if allowed_units.intersects(CalcUnits::TIME) { + if let Ok(t) = Time::parse_dimension(value, unit) { + return Ok(CalcNode::Leaf(Leaf::Time(t))); + } + } + if allowed_units.intersects(CalcUnits::RESOLUTION) { + if let Ok(t) = Resolution::parse_dimension(value, unit) { + return Ok(CalcNode::Leaf(Leaf::Resolution(t))); + } + } + return Err(location.new_custom_error(StyleParseErrorKind::UnspecifiedError)); + }, + &Token::Percentage { unit_value, .. } + if allowed_units.intersects(CalcUnits::PERCENTAGE) => + { + Ok(CalcNode::Leaf(Leaf::Percentage(unit_value))) + }, + &Token::ParenthesisBlock => input.parse_nested_block(|input| { + CalcNode::parse_argument(context, input, allowed_units) + }), + &Token::Function(ref name) => { + let function = CalcNode::math_function(context, name, location)?; + CalcNode::parse(context, input, function, allowed_units) + }, + &Token::Ident(ref ident) => { + let number = match_ignore_ascii_case! { &**ident, + "e" if trig_enabled() => std::f32::consts::E, + "pi" if trig_enabled() => std::f32::consts::PI, + "infinity" if nan_inf_enabled() => f32::INFINITY, + "-infinity" if nan_inf_enabled() => f32::NEG_INFINITY, + "nan" if nan_inf_enabled() => f32::NAN, + _ => return Err(location.new_unexpected_token_error(Token::Ident(ident.clone()))), + }; + Ok(CalcNode::Leaf(Leaf::Number(number))) + }, + t => Err(location.new_unexpected_token_error(t.clone())), + } + } + + /// Parse a top-level `calc` expression, with all nested sub-expressions. + /// + /// This is in charge of parsing, for example, `2 + 3 * 100%`. + fn parse<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + allowed_units: CalcUnits, + ) -> Result<Self, ParseError<'i>> { + // TODO: Do something different based on the function name. In + // particular, for non-calc function we need to take a list of + // comma-separated arguments and such. + input.parse_nested_block(|input| { + match function { + MathFunction::Calc => Self::parse_argument(context, input, allowed_units), + MathFunction::Clamp => { + let min = Self::parse_argument(context, input, allowed_units)?; + input.expect_comma()?; + let center = Self::parse_argument(context, input, allowed_units)?; + input.expect_comma()?; + let max = Self::parse_argument(context, input, allowed_units)?; + Ok(Self::Clamp { + min: Box::new(min), + center: Box::new(center), + max: Box::new(max), + }) + }, + MathFunction::Round => { + let strategy = input.try_parse(parse_rounding_strategy); + + // <rounding-strategy> = nearest | up | down | to-zero + // https://drafts.csswg.org/css-values-4/#calc-syntax + fn parse_rounding_strategy<'i, 't>( + input: &mut Parser<'i, 't>, + ) -> Result<RoundingStrategy, ParseError<'i>> { + Ok(try_match_ident_ignore_ascii_case! { input, + "nearest" => RoundingStrategy::Nearest, + "up" => RoundingStrategy::Up, + "down" => RoundingStrategy::Down, + "to-zero" => RoundingStrategy::ToZero, + }) + } + + if strategy.is_ok() { + input.expect_comma()?; + } + + let value = Self::parse_argument(context, input, allowed_units)?; + input.expect_comma()?; + let step = Self::parse_argument(context, input, allowed_units)?; + + Ok(Self::Round { + strategy: strategy.unwrap_or(RoundingStrategy::Nearest), + value: Box::new(value), + step: Box::new(step), + }) + }, + MathFunction::Mod | MathFunction::Rem => { + let dividend = Self::parse_argument(context, input, allowed_units)?; + input.expect_comma()?; + let divisor = Self::parse_argument(context, input, allowed_units)?; + + let op = match function { + MathFunction::Mod => ModRemOp::Mod, + MathFunction::Rem => ModRemOp::Rem, + _ => unreachable!(), + }; + Ok(Self::ModRem { + dividend: Box::new(dividend), + divisor: Box::new(divisor), + op, + }) + }, + MathFunction::Min | MathFunction::Max => { + // TODO(emilio): The common case for parse_comma_separated + // is just one element, but for min / max is two, really... + // + // Consider adding an API to cssparser to specify the + // initial vector capacity? + let arguments = input.parse_comma_separated(|input| { + Self::parse_argument(context, input, allowed_units) + })?; + + let op = match function { + MathFunction::Min => MinMaxOp::Min, + MathFunction::Max => MinMaxOp::Max, + _ => unreachable!(), + }; + + Ok(Self::MinMax(arguments.into(), op)) + }, + MathFunction::Sin | MathFunction::Cos | MathFunction::Tan => { + let a = Self::parse_angle_argument(context, input)?; + + let number = match function { + MathFunction::Sin => a.sin(), + MathFunction::Cos => a.cos(), + MathFunction::Tan => a.tan(), + _ => unsafe { + debug_unreachable!("We just checked!"); + }, + }; + + Ok(Self::Leaf(Leaf::Number(number))) + }, + MathFunction::Asin | MathFunction::Acos | MathFunction::Atan => { + let a = Self::parse_number_argument(context, input)?; + + let radians = match function { + MathFunction::Asin => a.asin(), + MathFunction::Acos => a.acos(), + MathFunction::Atan => a.atan(), + _ => unsafe { + debug_unreachable!("We just checked!"); + }, + }; + + Ok(Self::Leaf(Leaf::Angle(Angle::from_radians(radians)))) + }, + MathFunction::Atan2 => { + let a = Self::parse_argument(context, input, CalcUnits::ALL)?; + input.expect_comma()?; + let b = Self::parse_argument(context, input, CalcUnits::ALL)?; + + let radians = Self::try_resolve(input, || { + if let Ok(a) = a.to_number() { + let b = b.to_number()?; + return Ok(a.atan2(b)); + } + + if let Ok(a) = a.to_percentage() { + let b = b.to_percentage()?; + return Ok(a.atan2(b)); + } + + if let Ok(a) = a.to_time(None) { + let b = b.to_time(None)?; + return Ok(a.seconds().atan2(b.seconds())); + } + + if let Ok(a) = a.to_angle() { + let b = b.to_angle()?; + return Ok(a.radians().atan2(b.radians())); + } + + if let Ok(a) = a.to_resolution() { + let b = b.to_resolution()?; + return Ok(a.dppx().atan2(b.dppx())); + } + + let a = a.into_length_or_percentage(AllowedNumericType::All)?; + let b = b.into_length_or_percentage(AllowedNumericType::All)?; + let (a, b) = CalcLengthPercentage::same_unit_length_as(&a, &b).ok_or(())?; + + Ok(a.atan2(b)) + })?; + + Ok(Self::Leaf(Leaf::Angle(Angle::from_radians(radians)))) + }, + MathFunction::Pow => { + let a = Self::parse_number_argument(context, input)?; + input.expect_comma()?; + let b = Self::parse_number_argument(context, input)?; + + let number = a.powf(b); + + Ok(Self::Leaf(Leaf::Number(number))) + }, + MathFunction::Sqrt => { + let a = Self::parse_number_argument(context, input)?; + + let number = a.sqrt(); + + Ok(Self::Leaf(Leaf::Number(number))) + }, + MathFunction::Hypot => { + let arguments = input.parse_comma_separated(|input| { + Self::parse_argument(context, input, allowed_units) + })?; + + Ok(Self::Hypot(arguments.into())) + }, + MathFunction::Log => { + let a = Self::parse_number_argument(context, input)?; + let b = input + .try_parse(|input| { + input.expect_comma()?; + Self::parse_number_argument(context, input) + }) + .ok(); + + let number = match b { + Some(b) => a.log(b), + None => a.ln(), + }; + + Ok(Self::Leaf(Leaf::Number(number))) + }, + MathFunction::Exp => { + let a = Self::parse_number_argument(context, input)?; + + let number = a.exp(); + + Ok(Self::Leaf(Leaf::Number(number))) + }, + } + }) + } + + fn parse_angle_argument<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + ) -> Result<CSSFloat, ParseError<'i>> { + let argument = Self::parse_argument(context, input, CalcUnits::ANGLE)?; + argument + .to_number() + .or_else(|()| Ok(argument.to_angle()?.radians())) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + fn parse_number_argument<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + ) -> Result<CSSFloat, ParseError<'i>> { + Self::parse_argument(context, input, CalcUnits::empty())? + .to_number() + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + fn parse_argument<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + allowed_units: CalcUnits, + ) -> Result<Self, ParseError<'i>> { + let mut sum = SmallVec::<[CalcNode; 1]>::new(); + sum.push(Self::parse_product(context, input, allowed_units)?); + + loop { + let start = input.state(); + match input.next_including_whitespace() { + Ok(&Token::WhiteSpace(_)) => { + if input.is_exhausted() { + break; // allow trailing whitespace + } + match *input.next()? { + Token::Delim('+') => { + sum.push(Self::parse_product(context, input, allowed_units)?); + }, + Token::Delim('-') => { + let mut rhs = Self::parse_product(context, input, allowed_units)?; + rhs.negate(); + sum.push(rhs); + }, + _ => { + input.reset(&start); + break; + }, + } + }, + _ => { + input.reset(&start); + break; + }, + } + } + + Ok(if sum.len() == 1 { + sum.drain(..).next().unwrap() + } else { + Self::Sum(sum.into_boxed_slice().into()) + }) + } + + /// Parse a top-level `calc` expression, and all the products that may + /// follow, and stop as soon as a non-product expression is found. + /// + /// This should parse correctly: + /// + /// * `2` + /// * `2 * 2` + /// * `2 * 2 + 2` (but will leave the `+ 2` unparsed). + /// + fn parse_product<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + allowed_units: CalcUnits, + ) -> Result<Self, ParseError<'i>> { + let mut node = Self::parse_one(context, input, allowed_units)?; + + loop { + let start = input.state(); + match input.next() { + Ok(&Token::Delim('*')) => { + let rhs = Self::parse_one(context, input, allowed_units)?; + if let Ok(rhs) = rhs.to_number() { + node.mul_by(rhs); + } else if let Ok(number) = node.to_number() { + node = rhs; + node.mul_by(number); + } else { + // One of the two parts of the multiplication has to be + // a number, at least until we implement unit math. + return Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)); + } + }, + Ok(&Token::Delim('/')) => { + let rhs = Self::parse_one(context, input, allowed_units)?; + // Dividing by units is not ok. + // + // TODO(emilio): Eventually it should be. + let number = match rhs.to_number() { + Ok(n) if n != 0. || nan_inf_enabled() => n, + _ => { + return Err( + input.new_custom_error(StyleParseErrorKind::UnspecifiedError) + ) + }, + }; + node.mul_by(1. / number); + }, + _ => { + input.reset(&start); + break; + }, + } + } + + Ok(node) + } + + fn try_resolve<'i, 't, F>( + input: &Parser<'i, 't>, + closure: F, + ) -> Result<CSSFloat, ParseError<'i>> + where + F: FnOnce() -> Result<CSSFloat, ()>, + { + closure().map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Tries to simplify this expression into a `<length>` or `<percentage>` + /// value. + fn into_length_or_percentage( + mut self, + clamping_mode: AllowedNumericType, + ) -> Result<CalcLengthPercentage, ()> { + // Keep track of whether there's any invalid member of the calculation, + // so as to reject the calculation properly at parse-time. + let mut any_invalid = false; + self.visit_depth_first(|node| { + if let CalcNode::Leaf(ref l) = *node { + any_invalid |= !matches!(*l, Leaf::Percentage(..) | Leaf::Length(..)); + } + node.simplify_and_sort_direct_children(); + }); + + if any_invalid { + return Err(()); + } + + Ok(CalcLengthPercentage { + clamping_mode, + node: self, + }) + } + + /// Tries to simplify this expression into a `<time>` value. + fn to_time(&self, clamping_mode: Option<AllowedNumericType>) -> Result<Time, ()> { + let seconds = self.resolve(|leaf| match *leaf { + Leaf::Time(ref time) => Ok(time.seconds()), + _ => Err(()), + })?; + + Ok(Time::from_seconds_with_calc_clamping_mode( + if nan_inf_enabled() { + seconds + } else { + crate::values::normalize(seconds) + }, + clamping_mode, + )) + } + + /// Tries to simplify the expression into a `<resolution>` value. + fn to_resolution(&self) -> Result<Resolution, ()> { + let dppx = self.resolve(|leaf| match *leaf { + Leaf::Resolution(ref r) => Ok(r.dppx()), + _ => Err(()), + })?; + + Ok(Resolution::from_dppx_calc(if nan_inf_enabled() { + dppx + } else { + crate::values::normalize(dppx) + })) + } + + /// Tries to simplify this expression into an `Angle` value. + fn to_angle(&self) -> Result<Angle, ()> { + let degrees = self.resolve(|leaf| match *leaf { + Leaf::Angle(ref angle) => Ok(angle.degrees()), + _ => Err(()), + })?; + let result = Angle::from_calc(if nan_inf_enabled() { + degrees + } else { + crate::values::normalize(degrees) + }); + Ok(result) + } + + /// Tries to simplify this expression into a `<number>` value. + fn to_number(&self) -> Result<CSSFloat, ()> { + self.resolve(|leaf| match *leaf { + Leaf::Number(n) => Ok(n), + _ => Err(()), + }) + } + + /// Tries to simplify this expression into a `<percentage>` value. + fn to_percentage(&self) -> Result<CSSFloat, ()> { + self.resolve(|leaf| match *leaf { + Leaf::Percentage(p) => Ok(p), + _ => Err(()), + }) + } + + /// Given a function name, and the location from where the token came from, + /// return a mathematical function corresponding to that name or an error. + #[inline] + pub fn math_function<'i>( + context: &ParserContext, + name: &CowRcStr<'i>, + location: cssparser::SourceLocation, + ) -> Result<MathFunction, ParseError<'i>> { + use self::MathFunction::*; + + let function = match MathFunction::from_ident(&*name) { + Ok(f) => f, + Err(()) => { + return Err(location.new_unexpected_token_error(Token::Function(name.clone()))) + }, + }; + + let enabled = if context.chrome_rules_enabled() { + true + } else if matches!(function, Sin | Cos | Tan | Asin | Acos | Atan | Atan2) { + trig_enabled() + } else if matches!(function, Round) { + static_prefs::pref!("layout.css.round.enabled") + } else if matches!(function, Mod | Rem) { + static_prefs::pref!("layout.css.mod-rem.enabled") + } else if matches!(function, Pow | Sqrt | Hypot | Log | Exp) { + static_prefs::pref!("layout.css.exp.enabled") + } else { + true + }; + + if !enabled { + return Err(location.new_unexpected_token_error(Token::Function(name.clone()))); + } + + Ok(function) + } + + /// Convenience parsing function for integers. + pub fn parse_integer<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<CSSInteger, ParseError<'i>> { + Self::parse_number(context, input, function).map(|n| n.round() as CSSInteger) + } + + /// Convenience parsing function for `<length> | <percentage>`. + pub fn parse_length_or_percentage<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + clamping_mode: AllowedNumericType, + function: MathFunction, + ) -> Result<CalcLengthPercentage, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::LENGTH_PERCENTAGE)? + .into_length_or_percentage(clamping_mode) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for percentages. + pub fn parse_percentage<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<CSSFloat, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::PERCENTAGE)? + .to_percentage() + .map(crate::values::normalize) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<length>`. + pub fn parse_length<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + clamping_mode: AllowedNumericType, + function: MathFunction, + ) -> Result<CalcLengthPercentage, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::LENGTH)? + .into_length_or_percentage(clamping_mode) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<number>`. + pub fn parse_number<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<CSSFloat, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::empty())? + .to_number() + .map(crate::values::normalize) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<angle>`. + pub fn parse_angle<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<Angle, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::ANGLE)? + .to_angle() + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<time>`. + pub fn parse_time<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + clamping_mode: AllowedNumericType, + function: MathFunction, + ) -> Result<Time, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::TIME)? + .to_time(Some(clamping_mode)) + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<resolution>`. + pub fn parse_resolution<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<Resolution, ParseError<'i>> { + Self::parse(context, input, function, CalcUnits::RESOLUTION)? + .to_resolution() + .map_err(|()| input.new_custom_error(StyleParseErrorKind::UnspecifiedError)) + } + + /// Convenience parsing function for `<number>` or `<percentage>`. + pub fn parse_number_or_percentage<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<NumberOrPercentage, ParseError<'i>> { + let node = Self::parse(context, input, function, CalcUnits::PERCENTAGE)?; + + if let Ok(value) = node.to_number() { + return Ok(NumberOrPercentage::Number { value }); + } + + match node.to_percentage() { + Ok(unit_value) => Ok(NumberOrPercentage::Percentage { unit_value }), + Err(()) => Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)), + } + } + + /// Convenience parsing function for `<number>` or `<angle>`. + pub fn parse_angle_or_number<'i, 't>( + context: &ParserContext, + input: &mut Parser<'i, 't>, + function: MathFunction, + ) -> Result<AngleOrNumber, ParseError<'i>> { + let node = Self::parse(context, input, function, CalcUnits::ANGLE)?; + + if let Ok(angle) = node.to_angle() { + let degrees = angle.degrees(); + return Ok(AngleOrNumber::Angle { degrees }); + } + + match node.to_number() { + Ok(value) => Ok(AngleOrNumber::Number { value }), + Err(()) => Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError)), + } + } +} |