From 6bf0a5cb5034a7e684dcc3500e841785237ce2dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:32:43 +0200 Subject: Adding upstream version 1:115.7.0. Signed-off-by: Daniel Baumann --- servo/components/style/values/generics/calc.rs | 1343 ++++++++++++++++++++++++ 1 file changed, 1343 insertions(+) create mode 100644 servo/components/style/values/generics/calc.rs (limited to 'servo/components/style/values/generics/calc.rs') diff --git a/servo/components/style/values/generics/calc.rs b/servo/components/style/values/generics/calc.rs new file mode 100644 index 0000000000..3132e56342 --- /dev/null +++ b/servo/components/style/values/generics/calc.rs @@ -0,0 +1,1343 @@ +/* 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 num_traits::{Float, Zero}; +use smallvec::SmallVec; +use std::fmt::{self, Write}; +use std::ops::{Add, Div, Mul, Neg, Rem, Sub}; +use std::{cmp, mem}; +use style_traits::{CssWriter, ToCss}; + +/// Whether we're a `min` or `max` function. +#[derive( + Clone, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + ToAnimatedZero, + ToResolvedValue, + ToShmem, +)] +#[repr(u8)] +pub enum MinMaxOp { + /// `min()` + Min, + /// `max()` + Max, +} + +/// Whether we're a `mod` or `rem` function. +#[derive( + Clone, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + ToAnimatedZero, + ToResolvedValue, + ToShmem, +)] +#[repr(u8)] +pub enum ModRemOp { + /// `mod()` + Mod, + /// `rem()` + Rem, +} + +/// The strategy used in `round()` +#[derive( + Clone, + Copy, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + ToAnimatedZero, + ToResolvedValue, + ToShmem, +)] +#[repr(u8)] +pub enum RoundingStrategy { + /// `round(nearest, a, b)` + /// round a to the nearest multiple of b + Nearest, + /// `round(up, a, b)` + /// round a up to the nearest multiple of b + Up, + /// `round(down, a, b)` + /// round a down to the nearest multiple of b + Down, + /// `round(to-zero, a, b)` + /// round a to the nearest multiple of b that is towards zero + ToZero, +} + +/// This determines the order in which we serialize members of a calc() sum. +/// +/// See https://drafts.csswg.org/css-values-4/#sort-a-calculations-children +#[derive(Clone, Copy, Debug, Eq, Ord, PartialEq, PartialOrd)] +#[allow(missing_docs)] +pub enum SortKey { + Number, + Percentage, + Cap, + Ch, + Cqb, + Cqh, + Cqi, + Cqmax, + Cqmin, + Cqw, + Deg, + Dppx, + Dvb, + Dvh, + Dvi, + Dvmax, + Dvmin, + Dvw, + Em, + Ex, + Ic, + Lvb, + Lvh, + Lvi, + Lvmax, + Lvmin, + Lvw, + Px, + Rem, + Sec, + Svb, + Svh, + Svi, + Svmax, + Svmin, + Svw, + Vb, + Vh, + Vi, + Vmax, + Vmin, + Vw, + Other, +} + +/// A generic node in a calc expression. +/// +/// FIXME: This would be much more elegant if we used `Self` in the types below, +/// but we can't because of https://github.com/serde-rs/serde/issues/1565. +/// +/// FIXME: The following annotations are to workaround an LLVM inlining bug, see +/// bug 1631929. +/// +/// cbindgen:destructor-attributes=MOZ_NEVER_INLINE +/// cbindgen:copy-constructor-attributes=MOZ_NEVER_INLINE +/// cbindgen:eq-attributes=MOZ_NEVER_INLINE +#[repr(u8)] +#[derive( + Clone, + Debug, + Deserialize, + MallocSizeOf, + PartialEq, + Serialize, + ToAnimatedZero, + ToResolvedValue, + ToShmem, +)] +pub enum GenericCalcNode { + /// A leaf node. + Leaf(L), + /// A node that negates its children, e.g. Negate(1) == -1. + Negate(Box>), + /// A sum node, representing `a + b + c` where a, b, and c are the + /// arguments. + Sum(crate::OwnedSlice>), + /// A `min` or `max` function. + MinMax(crate::OwnedSlice>, MinMaxOp), + /// A `clamp()` function. + Clamp { + /// The minimum value. + min: Box>, + /// The central value. + center: Box>, + /// The maximum value. + max: Box>, + }, + /// A `round()` function. + Round { + /// The rounding strategy. + strategy: RoundingStrategy, + /// The value to round. + value: Box>, + /// The step value. + step: Box>, + }, + /// A `mod()` or `rem()` function. + ModRem { + /// The dividend calculation. + dividend: Box>, + /// The divisor calculation. + divisor: Box>, + /// Is the function mod or rem? + op: ModRemOp, + }, + /// A `hypot()` function + Hypot(crate::OwnedSlice>), +} + +pub use self::GenericCalcNode as CalcNode; + +/// A trait that represents all the stuff a valid leaf of a calc expression. +pub trait CalcNodeLeaf: Clone + Sized + PartialOrd + PartialEq + ToCss { + /// Returns the unitless value of this leaf. + fn unitless_value(&self) -> f32; + + /// Whether this value is known-negative. + fn is_negative(&self) -> bool { + self.unitless_value().is_sign_negative() + } + + /// Whether this value is infinite. + fn is_infinite(&self) -> bool { + self.unitless_value().is_infinite() + } + + /// Whether this value is zero. + fn is_zero(&self) -> bool { + self.unitless_value().is_zero() + } + + /// Whether this value is NaN. + fn is_nan(&self) -> bool { + self.unitless_value().is_nan() + } + + /// Tries to merge one sum to another, that is, perform `x` + `y`. + fn try_sum_in_place(&mut self, other: &Self) -> Result<(), ()>; + + /// Tries a generic arithmetic operation. + fn try_op(&self, other: &Self, op: O) -> Result + where + O: Fn(f32, f32) -> f32; + + /// Map the value of this node with the given operation. + fn map(&mut self, op: impl FnMut(f32) -> f32); + + /// Negates the leaf. + fn negate(&mut self) { + self.map(std::ops::Neg::neg); + } + + /// Canonicalizes the expression if necessary. + fn simplify(&mut self); + + /// Returns the sort key for simplification. + fn sort_key(&self) -> SortKey; +} + +/// The level of any argument being serialized in `to_css_impl`. +enum ArgumentLevel { + /// The root of a calculation tree. + CalculationRoot, + /// The root of an operand node's argument, e.g. `min(10, 20)`, `10` and `20` will have this + /// level, but min in this case will have `TopMost`. + ArgumentRoot, + /// Any other values serialized in the tree. + Nested, +} + +impl CalcNode { + /// Negate the node inline. If the node is distributive, it is replaced by the result, + /// otherwise the node is wrapped in a [`Negate`] node. + pub fn negate(&mut self) { + match *self { + CalcNode::Leaf(ref mut leaf) => leaf.map(|l| l.neg()), + CalcNode::Negate(ref mut value) => { + // Don't negate the value here. Replace `self` with it's child. + let result = mem::replace( + value.as_mut(), + Self::MinMax(Default::default(), MinMaxOp::Max), + ); + *self = result; + }, + CalcNode::Sum(ref mut children) => { + for child in children.iter_mut() { + child.negate(); + } + }, + CalcNode::MinMax(ref mut children, ref mut op) => { + for child in children.iter_mut() { + child.negate(); + } + + // Negating min-max means the operation is swapped. + *op = match *op { + MinMaxOp::Min => MinMaxOp::Max, + MinMaxOp::Max => MinMaxOp::Min, + }; + }, + CalcNode::Clamp { + ref mut min, + ref mut center, + ref mut max, + } => { + min.negate(); + center.negate(); + max.negate(); + + mem::swap(min, max); + }, + CalcNode::Round { + ref mut value, + ref mut step, + .. + } => { + value.negate(); + step.negate(); + }, + CalcNode::ModRem { + ref mut dividend, + ref mut divisor, + .. + } => { + dividend.negate(); + divisor.negate(); + }, + CalcNode::Hypot(ref mut children) => { + for child in children.iter_mut() { + child.negate(); + } + }, + } + } + + fn sort_key(&self) -> SortKey { + match *self { + Self::Leaf(ref l) => l.sort_key(), + _ => SortKey::Other, + } + } + + /// Returns the leaf if we can (if simplification has allowed it). + pub fn as_leaf(&self) -> Option<&L> { + match *self { + Self::Leaf(ref l) => Some(l), + _ => None, + } + } + + /// Tries to merge one sum to another, that is, perform `x` + `y`. + fn try_sum_in_place(&mut self, other: &Self) -> Result<(), ()> { + match (self, other) { + (&mut CalcNode::Leaf(ref mut one), &CalcNode::Leaf(ref other)) => { + one.try_sum_in_place(other) + }, + _ => Err(()), + } + } + + /// Tries to apply a generic arithmentic operator + fn try_op(&self, other: &Self, op: O) -> Result + where + O: Fn(f32, f32) -> f32, + { + match (self, other) { + (&CalcNode::Leaf(ref one), &CalcNode::Leaf(ref other)) => { + Ok(CalcNode::Leaf(one.try_op(other, op)?)) + }, + _ => Err(()), + } + } + + /// Map the value of this node with the given operation. + pub fn map(&mut self, mut op: impl FnMut(f32) -> f32) { + fn map_internal(node: &mut CalcNode, op: &mut impl FnMut(f32) -> f32) { + match node { + CalcNode::Leaf(l) => l.map(op), + CalcNode::Negate(v) => map_internal(v, op), + CalcNode::Sum(children) => { + for node in &mut **children { + map_internal(node, op); + } + }, + CalcNode::MinMax(children, _) => { + for node in &mut **children { + map_internal(node, op); + } + }, + CalcNode::Clamp { min, center, max } => { + map_internal(min, op); + map_internal(center, op); + map_internal(max, op); + }, + CalcNode::Round { value, step, .. } => { + map_internal(value, op); + map_internal(step, op); + }, + CalcNode::ModRem { + dividend, divisor, .. + } => { + map_internal(dividend, op); + map_internal(divisor, op); + }, + CalcNode::Hypot(children) => { + for node in &mut **children { + map_internal(node, op); + } + }, + } + } + + map_internal(self, &mut op); + } + + /// Convert this `CalcNode` into a `CalcNode` with a different leaf kind. + pub fn map_leaves(&self, mut map: F) -> CalcNode + where + O: CalcNodeLeaf, + F: FnMut(&L) -> O, + { + self.map_leaves_internal(&mut map) + } + + fn map_leaves_internal(&self, map: &mut F) -> CalcNode + where + O: CalcNodeLeaf, + F: FnMut(&L) -> O, + { + fn map_children( + children: &[CalcNode], + map: &mut F, + ) -> crate::OwnedSlice> + where + L: CalcNodeLeaf, + O: CalcNodeLeaf, + F: FnMut(&L) -> O, + { + children + .iter() + .map(|c| c.map_leaves_internal(map)) + .collect() + } + + match *self { + Self::Leaf(ref l) => CalcNode::Leaf(map(l)), + Self::Negate(ref c) => CalcNode::Negate(Box::new(c.map_leaves_internal(map))), + Self::Sum(ref c) => CalcNode::Sum(map_children(c, map)), + Self::MinMax(ref c, op) => CalcNode::MinMax(map_children(c, map), op), + Self::Clamp { + ref min, + ref center, + ref max, + } => { + let min = Box::new(min.map_leaves_internal(map)); + let center = Box::new(center.map_leaves_internal(map)); + let max = Box::new(max.map_leaves_internal(map)); + CalcNode::Clamp { min, center, max } + }, + Self::Round { + strategy, + ref value, + ref step, + } => { + let value = Box::new(value.map_leaves_internal(map)); + let step = Box::new(step.map_leaves_internal(map)); + CalcNode::Round { + strategy, + value, + step, + } + }, + Self::ModRem { + ref dividend, + ref divisor, + op, + } => { + let dividend = Box::new(dividend.map_leaves_internal(map)); + let divisor = Box::new(divisor.map_leaves_internal(map)); + CalcNode::ModRem { + dividend, + divisor, + op, + } + }, + Self::Hypot(ref c) => CalcNode::Hypot(map_children(c, map)), + } + } + + /// Resolves the expression returning a value of `O`, given a function to + /// turn a leaf into the relevant value. + pub fn resolve( + &self, + mut leaf_to_output_fn: impl FnMut(&L) -> Result, + ) -> Result + where + O: PartialOrd + + PartialEq + + Add + + Mul + + Div + + Sub + + Zero + + Float + + Copy, + { + self.resolve_internal(&mut leaf_to_output_fn) + } + + fn resolve_internal(&self, leaf_to_output_fn: &mut F) -> Result + where + O: PartialOrd + + PartialEq + + Add + + Mul + + Div + + Sub + + Zero + + Float + + Copy, + F: FnMut(&L) -> Result, + { + Ok(match *self { + Self::Leaf(ref l) => return leaf_to_output_fn(l), + Self::Negate(ref c) => c.resolve_internal(leaf_to_output_fn)?.neg(), + Self::Sum(ref c) => { + let mut result = Zero::zero(); + for child in &**c { + result = result + child.resolve_internal(leaf_to_output_fn)?; + } + result + }, + Self::MinMax(ref nodes, op) => { + let mut result = nodes[0].resolve_internal(leaf_to_output_fn)?; + + if result.is_nan() { + return Ok(result); + } + + for node in nodes.iter().skip(1) { + let candidate = node.resolve_internal(leaf_to_output_fn)?; + + if candidate.is_nan() { + result = candidate; + break; + } + + let candidate_wins = match op { + MinMaxOp::Min => candidate < result, + MinMaxOp::Max => candidate > result, + }; + if candidate_wins { + result = candidate; + } + } + result + }, + Self::Clamp { + ref min, + ref center, + ref max, + } => { + let min = min.resolve_internal(leaf_to_output_fn)?; + let center = center.resolve_internal(leaf_to_output_fn)?; + let max = max.resolve_internal(leaf_to_output_fn)?; + + let mut result = center; + if result > max { + result = max; + } + if result < min { + result = min + } + + if min.is_nan() || center.is_nan() || max.is_nan() { + result = ::nan(); + } + + result + }, + Self::Round { + strategy, + ref value, + ref step, + } => { + let value = value.resolve_internal(leaf_to_output_fn)?; + let step = step.resolve_internal(leaf_to_output_fn)?; + + // TODO(emilio): Seems like at least a few of these + // special-cases could be removed if we do the math in a + // particular order. + if step.is_zero() { + return Ok(::nan()); + } + + if value.is_infinite() && step.is_infinite() { + return Ok(::nan()); + } + + if value.is_infinite() { + return Ok(value); + } + + if step.is_infinite() { + match strategy { + RoundingStrategy::Nearest | RoundingStrategy::ToZero => { + return if value.is_sign_negative() { + Ok(::neg_zero()) + } else { + Ok(::zero()) + } + }, + RoundingStrategy::Up => { + return if !value.is_sign_negative() && !value.is_zero() { + Ok(::infinity()) + } else if !value.is_sign_negative() && value.is_zero() { + Ok(value) + } else { + Ok(::neg_zero()) + } + }, + RoundingStrategy::Down => { + return if value.is_sign_negative() && !value.is_zero() { + Ok(::neg_infinity()) + } else if value.is_sign_negative() && value.is_zero() { + Ok(value) + } else { + Ok(::zero()) + } + }, + } + } + + let div = value / step; + let lower_bound = div.floor() * step; + let upper_bound = div.ceil() * step; + + match strategy { + RoundingStrategy::Nearest => { + // In case of a tie, use the upper bound + if value - lower_bound < upper_bound - value { + lower_bound + } else { + upper_bound + } + }, + RoundingStrategy::Up => upper_bound, + RoundingStrategy::Down => lower_bound, + RoundingStrategy::ToZero => { + // In case of a tie, use the upper bound + if lower_bound.abs() < upper_bound.abs() { + lower_bound + } else { + upper_bound + } + }, + } + }, + Self::ModRem { + ref dividend, + ref divisor, + op, + } => { + let dividend = dividend.resolve_internal(leaf_to_output_fn)?; + let divisor = divisor.resolve_internal(leaf_to_output_fn)?; + + // In mod(A, B) only, if B is infinite and A has opposite sign to B + // (including an oppositely-signed zero), the result is NaN. + // https://drafts.csswg.org/css-values/#round-infinities + if matches!(op, ModRemOp::Mod) && + divisor.is_infinite() && + dividend.is_sign_negative() != divisor.is_sign_negative() + { + return Ok(::nan()); + } + + match op { + ModRemOp::Mod => dividend - divisor * (dividend / divisor).floor(), + ModRemOp::Rem => dividend - divisor * (dividend / divisor).trunc(), + } + }, + Self::Hypot(ref c) => { + let mut result: O = Zero::zero(); + for child in &**c { + result = result + child.resolve_internal(leaf_to_output_fn)?.powi(2); + } + result.sqrt() + }, + }) + } + + fn is_negative_leaf(&self) -> bool { + match *self { + Self::Leaf(ref l) => l.is_negative(), + _ => false, + } + } + + fn is_zero_leaf(&self) -> bool { + match *self { + Self::Leaf(ref l) => l.is_zero(), + _ => false, + } + } + + fn is_infinite_leaf(&self) -> bool { + match *self { + Self::Leaf(ref l) => l.is_infinite(), + _ => false, + } + } + + /// Multiplies the node by a scalar. + pub fn mul_by(&mut self, scalar: f32) { + match *self { + Self::Leaf(ref mut l) => l.map(|v| v * scalar), + Self::Negate(ref mut value) => value.mul_by(scalar), + // Multiplication is distributive across this. + Self::Sum(ref mut children) => { + for node in &mut **children { + node.mul_by(scalar); + } + }, + // This one is a bit trickier. + Self::MinMax(ref mut children, ref mut op) => { + for node in &mut **children { + node.mul_by(scalar); + } + + // For negatives we need to invert the operation. + if scalar < 0. { + *op = match *op { + MinMaxOp::Min => MinMaxOp::Max, + MinMaxOp::Max => MinMaxOp::Min, + } + } + }, + // This one is slightly tricky too. + Self::Clamp { + ref mut min, + ref mut center, + ref mut max, + } => { + min.mul_by(scalar); + center.mul_by(scalar); + max.mul_by(scalar); + // For negatives we need to swap min / max. + if scalar < 0. { + mem::swap(min, max); + } + }, + Self::Round { + ref mut value, + ref mut step, + .. + } => { + value.mul_by(scalar); + step.mul_by(scalar); + }, + Self::ModRem { + ref mut dividend, + ref mut divisor, + .. + } => { + dividend.mul_by(scalar); + divisor.mul_by(scalar); + }, + // Not possible to handle negatives in this case, see: https://bugzil.la/1815448 + Self::Hypot(ref mut children) => { + for node in &mut **children { + node.mul_by(scalar); + } + }, + } + } + + /// Visits all the nodes in this calculation tree recursively, starting by + /// the leaves and bubbling all the way up. + /// + /// This is useful for simplification, but can also be used for validation + /// and such. + pub fn visit_depth_first(&mut self, mut f: impl FnMut(&mut Self)) { + self.visit_depth_first_internal(&mut f); + } + + fn visit_depth_first_internal(&mut self, f: &mut impl FnMut(&mut Self)) { + match *self { + Self::Clamp { + ref mut min, + ref mut center, + ref mut max, + } => { + min.visit_depth_first_internal(f); + center.visit_depth_first_internal(f); + max.visit_depth_first_internal(f); + }, + Self::Round { + ref mut value, + ref mut step, + .. + } => { + value.visit_depth_first_internal(f); + step.visit_depth_first_internal(f); + }, + Self::ModRem { + ref mut dividend, + ref mut divisor, + .. + } => { + dividend.visit_depth_first_internal(f); + divisor.visit_depth_first_internal(f); + }, + Self::Sum(ref mut children) | + Self::MinMax(ref mut children, _) | + Self::Hypot(ref mut children) => { + for child in &mut **children { + child.visit_depth_first_internal(f); + } + }, + Self::Negate(ref mut value) => { + value.visit_depth_first_internal(f); + }, + Self::Leaf(..) => {}, + } + f(self); + } + + /// Simplifies and sorts the calculation of a given node. All the nodes + /// below it should be simplified already, this only takes care of + /// simplifying directly nested nodes. So, probably should always be used in + /// combination with `visit_depth_first()`. + /// + /// This is only needed if it's going to be preserved after parsing (so, for + /// ``). Otherwise we can just evaluate it using + /// `resolve()`, and we'll come up with a simplified value anyways. + /// + /// + pub fn simplify_and_sort_direct_children(&mut self) { + macro_rules! replace_self_with { + ($slot:expr) => {{ + let dummy = Self::MinMax(Default::default(), MinMaxOp::Max); + let result = mem::replace($slot, dummy); + *self = result; + }}; + } + match *self { + Self::Clamp { + ref mut min, + ref mut center, + ref mut max, + } => { + // NOTE: clamp() is max(min, min(center, max)) + let min_cmp_center = match min.partial_cmp(¢er) { + Some(o) => o, + None => return, + }; + + // So if we can prove that min is more than center, then we won, + // as that's what we should always return. + if matches!(min_cmp_center, cmp::Ordering::Greater) { + return replace_self_with!(&mut **min); + } + + // Otherwise try with max. + let max_cmp_center = match max.partial_cmp(¢er) { + Some(o) => o, + None => return, + }; + + if matches!(max_cmp_center, cmp::Ordering::Less) { + // max is less than center, so we need to return effectively + // `max(min, max)`. + let max_cmp_min = match max.partial_cmp(&min) { + Some(o) => o, + None => { + debug_assert!( + false, + "We compared center with min and max, how are \ + min / max not comparable with each other?" + ); + return; + }, + }; + + if matches!(max_cmp_min, cmp::Ordering::Less) { + return replace_self_with!(&mut **min); + } + + return replace_self_with!(&mut **max); + } + + // Otherwise we're the center node. + return replace_self_with!(&mut **center); + }, + Self::Round { + strategy, + ref mut value, + ref mut step, + } => { + if step.is_zero_leaf() { + value.mul_by(f32::NAN); + return replace_self_with!(&mut **value); + } + + if value.is_infinite_leaf() && step.is_infinite_leaf() { + value.mul_by(f32::NAN); + return replace_self_with!(&mut **value); + } + + if value.is_infinite_leaf() { + return replace_self_with!(&mut **value); + } + + if step.is_infinite_leaf() { + match strategy { + RoundingStrategy::Nearest | RoundingStrategy::ToZero => { + value.mul_by(0.); + return replace_self_with!(&mut **value); + }, + RoundingStrategy::Up => { + if !value.is_negative_leaf() && !value.is_zero_leaf() { + value.mul_by(f32::INFINITY); + return replace_self_with!(&mut **value); + } else if !value.is_negative_leaf() && value.is_zero_leaf() { + return replace_self_with!(&mut **value); + } else { + value.mul_by(0.); + return replace_self_with!(&mut **value); + } + }, + RoundingStrategy::Down => { + if value.is_negative_leaf() && !value.is_zero_leaf() { + value.mul_by(f32::INFINITY); + return replace_self_with!(&mut **value); + } else if value.is_negative_leaf() && value.is_zero_leaf() { + return replace_self_with!(&mut **value); + } else { + value.mul_by(0.); + return replace_self_with!(&mut **value); + } + }, + } + } + + if step.is_negative_leaf() { + step.negate(); + } + + let remainder = match value.try_op(step, Rem::rem) { + Ok(res) => res, + Err(..) => return, + }; + + let (mut lower_bound, mut upper_bound) = if value.is_negative_leaf() { + let upper_bound = match value.try_op(&remainder, Sub::sub) { + Ok(res) => res, + Err(..) => return, + }; + + let lower_bound = match upper_bound.try_op(&step, Sub::sub) { + Ok(res) => res, + Err(..) => return, + }; + + (lower_bound, upper_bound) + } else { + let lower_bound = match value.try_op(&remainder, Sub::sub) { + Ok(res) => res, + Err(..) => return, + }; + + let upper_bound = match lower_bound.try_op(&step, Add::add) { + Ok(res) => res, + Err(..) => return, + }; + + (lower_bound, upper_bound) + }; + + match strategy { + RoundingStrategy::Nearest => { + let lower_diff = match value.try_op(&lower_bound, Sub::sub) { + Ok(res) => res, + Err(..) => return, + }; + + let upper_diff = match upper_bound.try_op(value, Sub::sub) { + Ok(res) => res, + Err(..) => return, + }; + + // In case of a tie, use the upper bound + if lower_diff < upper_diff { + return replace_self_with!(&mut lower_bound); + } else { + return replace_self_with!(&mut upper_bound); + } + }, + RoundingStrategy::Up => return replace_self_with!(&mut upper_bound), + RoundingStrategy::Down => return replace_self_with!(&mut lower_bound), + RoundingStrategy::ToZero => { + let mut lower_diff = lower_bound.clone(); + let mut upper_diff = upper_bound.clone(); + + if lower_diff.is_negative_leaf() { + lower_diff.negate(); + } + + if upper_diff.is_negative_leaf() { + upper_diff.negate(); + } + + // In case of a tie, use the upper bound + if lower_diff < upper_diff { + return replace_self_with!(&mut lower_bound); + } else { + return replace_self_with!(&mut upper_bound); + } + }, + }; + }, + Self::ModRem { + ref dividend, + ref divisor, + op, + } => { + let mut result = dividend.clone(); + + // In mod(A, B) only, if B is infinite and A has opposite sign to B + // (including an oppositely-signed zero), the result is NaN. + // https://drafts.csswg.org/css-values/#round-infinities + if matches!(op, ModRemOp::Mod) && + divisor.is_infinite_leaf() && + dividend.is_negative_leaf() != divisor.is_negative_leaf() + { + result.mul_by(f32::NAN); + return replace_self_with!(&mut *result); + } + + let result = match op { + ModRemOp::Mod => dividend.try_op(divisor, |a, b| a - b * (a / b).floor()), + ModRemOp::Rem => dividend.try_op(divisor, |a, b| a - b * (a / b).trunc()), + }; + + let mut result = match result { + Ok(res) => res, + Err(..) => return, + }; + + return replace_self_with!(&mut result); + }, + Self::MinMax(ref mut children, op) => { + let winning_order = match op { + MinMaxOp::Min => cmp::Ordering::Less, + MinMaxOp::Max => cmp::Ordering::Greater, + }; + + let mut result = 0; + for i in 1..children.len() { + let o = match children[i].partial_cmp(&children[result]) { + // We can't compare all the children, so we can't + // know which one will actually win. Bail out and + // keep ourselves as a min / max function. + // + // TODO: Maybe we could simplify compatible children, + // see https://github.com/w3c/csswg-drafts/issues/4756 + None => return, + Some(o) => o, + }; + + if o == winning_order { + result = i; + } + } + + replace_self_with!(&mut children[result]); + }, + Self::Sum(ref mut children_slot) => { + let mut sums_to_merge = SmallVec::<[_; 3]>::new(); + let mut extra_kids = 0; + for (i, child) in children_slot.iter().enumerate() { + if let Self::Sum(ref children) = *child { + extra_kids += children.len(); + sums_to_merge.push(i); + } + } + + // If we only have one kid, we've already simplified it, and it + // doesn't really matter whether it's a sum already or not, so + // lift it up and continue. + if children_slot.len() == 1 { + return replace_self_with!(&mut children_slot[0]); + } + + let mut children = mem::replace(children_slot, Default::default()).into_vec(); + + if !sums_to_merge.is_empty() { + children.reserve(extra_kids - sums_to_merge.len()); + // Merge all our nested sums, in reverse order so that the + // list indices are not invalidated. + for i in sums_to_merge.drain(..).rev() { + let kid_children = match children.swap_remove(i) { + Self::Sum(c) => c, + _ => unreachable!(), + }; + + // This would be nicer with + // https://github.com/rust-lang/rust/issues/59878 fixed. + children.extend(kid_children.into_vec()); + } + } + + debug_assert!(children.len() >= 2, "Should still have multiple kids!"); + + // Sort by spec order. + children.sort_unstable_by_key(|c| c.sort_key()); + + // NOTE: if the function returns true, by the docs of dedup_by, + // a is removed. + children.dedup_by(|a, b| b.try_sum_in_place(a).is_ok()); + + if children.len() == 1 { + // If only one children remains, lift it up, and carry on. + replace_self_with!(&mut children[0]); + } else { + // Else put our simplified children back. + *children_slot = children.into_boxed_slice().into(); + } + }, + Self::Hypot(ref children) => { + let mut result = match children[0].try_op(&children[0], Mul::mul) { + Ok(res) => res, + Err(..) => return, + }; + + for child in children.iter().skip(1) { + let square = match child.try_op(&child, Mul::mul) { + Ok(res) => res, + Err(..) => return, + }; + result = match result.try_op(&square, Add::add) { + Ok(res) => res, + Err(..) => return, + } + } + + result = match result.try_op(&result, |a, _| a.sqrt()) { + Ok(res) => res, + Err(..) => return, + }; + + replace_self_with!(&mut result); + }, + Self::Negate(ref mut child) => { + // Step 6. + match &mut **child { + CalcNode::Leaf(_) => { + // 1. If root’s child is a numeric value, return an equivalent numeric value, but + // with the value negated (0 - value). + child.negate(); + replace_self_with!(&mut **child); + }, + CalcNode::Negate(value) => { + // 2. If root’s child is a Negate node, return the child’s child. + replace_self_with!(&mut **value); + }, + _ => { + // 3. Return root. + }, + } + }, + Self::Leaf(ref mut l) => { + l.simplify(); + }, + } + } + + /// Simplifies and sorts the kids in the whole calculation subtree. + pub fn simplify_and_sort(&mut self) { + self.visit_depth_first(|node| node.simplify_and_sort_direct_children()) + } + + fn to_css_impl(&self, dest: &mut CssWriter, level: ArgumentLevel) -> fmt::Result + where + W: Write, + { + let write_closing_paren = match *self { + Self::MinMax(_, op) => { + dest.write_str(match op { + MinMaxOp::Max => "max(", + MinMaxOp::Min => "min(", + })?; + true + }, + Self::Clamp { .. } => { + dest.write_str("clamp(")?; + true + }, + Self::Round { strategy, .. } => { + match strategy { + RoundingStrategy::Nearest => dest.write_str("round("), + RoundingStrategy::Up => dest.write_str("round(up, "), + RoundingStrategy::Down => dest.write_str("round(down, "), + RoundingStrategy::ToZero => dest.write_str("round(to-zero, "), + }?; + + true + }, + Self::ModRem { op, .. } => { + dest.write_str(match op { + ModRemOp::Mod => "mod(", + ModRemOp::Rem => "rem(", + })?; + + true + }, + Self::Hypot(_) => { + dest.write_str("hypot(")?; + true + }, + Self::Negate(_) => { + // We never generate a [`Negate`] node as the root of a calculation, only inside + // [`Sum`] nodes as a child. Because negate nodes are handled by the [`Sum`] node + // directly (see below), this node will never be serialized. + debug_assert!( + false, + "We never serialize Negate nodes as they are handled inside Sum nodes." + ); + dest.write_str("(-1 * ")?; + true + }, + Self::Sum(_) => match level { + ArgumentLevel::CalculationRoot => { + dest.write_str("calc(")?; + true + }, + ArgumentLevel::ArgumentRoot => false, + ArgumentLevel::Nested => { + dest.write_str("(")?; + true + }, + }, + Self::Leaf(_) => match level { + ArgumentLevel::CalculationRoot => { + dest.write_str("calc(")?; + true + }, + ArgumentLevel::ArgumentRoot | ArgumentLevel::Nested => false, + }, + }; + + match *self { + Self::MinMax(ref children, _) | Self::Hypot(ref children) => { + let mut first = true; + for child in &**children { + if !first { + dest.write_str(", ")?; + } + first = false; + child.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + } + }, + Self::Negate(ref value) => value.to_css_impl(dest, ArgumentLevel::Nested)?, + Self::Sum(ref children) => { + let mut first = true; + for child in &**children { + if !first { + match child { + Self::Leaf(l) => { + if l.is_negative() { + dest.write_str(" - ")?; + let mut negated = l.clone(); + negated.negate(); + negated.to_css(dest)?; + } else { + dest.write_str(" + ")?; + l.to_css(dest)?; + } + }, + Self::Negate(n) => { + dest.write_str(" - ")?; + n.to_css_impl(dest, ArgumentLevel::Nested)?; + }, + _ => { + dest.write_str(" + ")?; + child.to_css_impl(dest, ArgumentLevel::Nested)?; + }, + } + } else { + first = false; + child.to_css_impl(dest, ArgumentLevel::Nested)?; + } + } + }, + Self::Clamp { + ref min, + ref center, + ref max, + } => { + min.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + dest.write_str(", ")?; + center.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + dest.write_str(", ")?; + max.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + }, + Self::Round { + ref value, + ref step, + .. + } => { + value.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + dest.write_str(", ")?; + step.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + }, + Self::ModRem { + ref dividend, + ref divisor, + .. + } => { + dividend.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + dest.write_str(", ")?; + divisor.to_css_impl(dest, ArgumentLevel::ArgumentRoot)?; + }, + Self::Leaf(ref l) => l.to_css(dest)?, + } + + if write_closing_paren { + dest.write_char(')')?; + } + Ok(()) + } +} + +impl PartialOrd for CalcNode { + fn partial_cmp(&self, other: &Self) -> Option { + match (self, other) { + (&CalcNode::Leaf(ref one), &CalcNode::Leaf(ref other)) => one.partial_cmp(other), + _ => None, + } + } +} + +impl ToCss for CalcNode { + /// + fn to_css(&self, dest: &mut CssWriter) -> fmt::Result + where + W: Write, + { + self.to_css_impl(dest, ArgumentLevel::CalculationRoot) + } +} -- cgit v1.2.3