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-rw-r--r--servo/components/style/values/specified/calc.rs918
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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/. */
+
+//! [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, 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,
+}
+
+/// 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),
+ /// `<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::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.
+ struct CalcUnits: u8 {
+ const LENGTH = 1 << 0;
+ const PERCENTAGE = 1 << 1;
+ const ANGLE = 1 << 2;
+ const TIME = 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;
+ }
+}
+
+/// 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()),
+ (&Number(ref one), &Number(ref other)) => one.partial_cmp(other),
+ _ => {
+ match *self {
+ Length(..) | Percentage(..) | Angle(..) | Time(..) | Number(..) => {},
+ }
+ 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::Angle(ref a) => a.degrees(),
+ Self::Time(ref t) => t.seconds(),
+ }
+ }
+
+ fn mul_by(&mut self, scalar: f32) {
+ match *self {
+ Self::Length(ref mut l) => {
+ // FIXME: For consistency this should probably convert absolute
+ // lengths into pixels.
+ *l = *l * scalar;
+ },
+ Self::Number(ref mut n) => {
+ *n *= scalar;
+ },
+ Self::Angle(ref mut a) => {
+ *a = Angle::from_calc(a.degrees() * scalar);
+ },
+ Self::Time(ref mut t) => {
+ *t = Time::from_calc(t.seconds() * scalar);
+ },
+ Self::Percentage(ref mut p) => {
+ *p *= scalar;
+ },
+ }
+ }
+
+ fn sort_key(&self) -> SortKey {
+ match *self {
+ Self::Number(..) => SortKey::Number,
+ Self::Percentage(..) => SortKey::Percentage,
+ Self::Time(..) => SortKey::Sec,
+ 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_calc(one.seconds() + other.seconds());
+ },
+ (&mut Length(ref mut one), &Length(ref other)) => {
+ *one = one.try_op(other, std::ops::Add::add)?;
+ },
+ _ => {
+ match *other {
+ Number(..) | Percentage(..) | Angle(..) | Time(..) | 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(),
+ ))));
+ },
+ (&Time(ref one), &Time(ref other)) => {
+ return Ok(Leaf::Time(specified::Time::from_calc(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(..) => {},
+ }
+ unsafe {
+ debug_unreachable!();
+ }
+ },
+ }
+ }
+}
+
+/// 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, /* from_calc = */ true) {
+ return Ok(CalcNode::Leaf(Leaf::Time(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(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 argument = Self::parse_argument(context, input, CalcUnits::ANGLE)?;
+ let radians = match argument.to_number() {
+ Ok(v) => v,
+ Err(()) => match argument.to_angle() {
+ Ok(angle) => angle.radians(),
+ Err(()) => {
+ return Err(
+ input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
+ )
+ },
+ },
+ };
+ let number = match function {
+ MathFunction::Sin => radians.sin(),
+ MathFunction::Cos => radians.cos(),
+ MathFunction::Tan => radians.tan(),
+ _ => unsafe {
+ debug_unreachable!("We just checked!");
+ },
+ };
+ Ok(Self::Leaf(Leaf::Number(number)))
+ },
+ MathFunction::Asin | MathFunction::Acos | MathFunction::Atan => {
+ let argument = Self::parse_argument(context, input, CalcUnits::empty())?;
+ let number = match argument.to_number() {
+ Ok(v) => v,
+ Err(()) => {
+ return Err(
+ input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
+ )
+ },
+ };
+
+ let radians = match function {
+ MathFunction::Asin => number.asin(),
+ MathFunction::Acos => number.acos(),
+ MathFunction::Atan => number.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)?;
+ fn resolve_atan2(a: CalcNode, b: CalcNode) -> Result<CSSFloat, ()> {
+ 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() {
+ let b = b.to_time()?;
+ 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()));
+ }
+
+ 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(())?;
+ return Ok(a.atan2(b));
+ }
+
+ let radians = match resolve_atan2(a, b) {
+ Ok(v) => v,
+ Err(()) => {
+ return Err(
+ input.new_custom_error(StyleParseErrorKind::UnspecifiedError)
+ )
+ },
+ };
+
+ Ok(Self::Leaf(Leaf::Angle(Angle::from_radians(radians))))
+ },
+ }
+ })
+ }
+
+ 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)
+ }
+
+ /// 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) -> Result<Time, ()> {
+ let seconds = self.resolve(|leaf| match *leaf {
+ Leaf::Time(ref t) => Ok(t.seconds()),
+ _ => Err(()),
+ })?;
+ Ok(Time::from_calc(crate::values::normalize(seconds)))
+ }
+
+ /// 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(()),
+ })?;
+ Ok(Angle::from_calc(crate::values::normalize(degrees)))
+ }
+
+ /// 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>(
+ 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 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 {
+ 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>,
+ function: MathFunction,
+ ) -> Result<Time, ParseError<'i>> {
+ Self::parse(context, input, function, CalcUnits::TIME)?
+ .to_time()
+ .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)),
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-12 12:37:26 +0000