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https://github.com/servo/servo.git
synced 2025-07-24 15:50:21 +01:00
Implement proper calc parsing
This commit is contained in:
David Zbarsky
parent
cb4d878169
commit
2bb6b4582a
2 changed files with 215 additions and 42 deletions
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@ -4,6 +4,7 @@
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#![feature(arc_unique)]
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#![feature(box_syntax)]
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#![feature(box_patterns)]
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#![feature(core_intrinsics)]
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#![feature(custom_attribute)]
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#![feature(custom_derive)]
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@ -353,6 +353,31 @@ pub mod specified {
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}
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}
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#[derive(Clone, Debug)]
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struct CalcSumNode {
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products: Vec<CalcProductNode>,
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}
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#[derive(Clone, Debug)]
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struct CalcProductNode {
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values: Vec<CalcValueNode>
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}
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#[derive(Clone, Debug)]
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enum CalcValueNode {
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Length(Length),
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Percentage(CSSFloat),
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Number(CSSFloat),
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Sum(Box<CalcSumNode>),
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}
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#[derive(Clone, Debug)]
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enum CalcAstNode {
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Add(CalcSumNode),
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Multiply(CalcProductNode),
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Value(CalcValueNode),
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}
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#[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
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pub struct Calc {
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pub absolute: Option<Au>,
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@ -361,46 +386,184 @@ pub mod specified {
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pub percentage: Option<CSSFloat>,
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}
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impl Calc {
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pub fn parse_component(&mut self, input: &mut Parser) -> Result<(), ()> {
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match try!(input.next()) {
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Token::Dimension(ref value, ref unit) => {
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let value = value.value;
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match_ignore_ascii_case! { unit,
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"px" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_PX) as i32)),
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"in" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_IN) as i32)),
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"cm" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_CM) as i32)),
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"mm" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_MM) as i32)),
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"pt" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_PT) as i32)),
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"pc" => self.absolute =
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Some(self.absolute.unwrap_or(Au(0)) + Au((value * AU_PER_PC) as i32))
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// font-relative
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/*"em" => Ok(Length::FontRelative(FontRelativeLength::Em(value))),
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"ex" => Ok(Length::FontRelative(FontRelativeLength::Ex(value))),
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"rem" => Ok(Length::FontRelative(FontRelativeLength::Rem(value))),
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// viewport percentages
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"vw" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vw(value))),
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"vh" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vh(value))),
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"vmin" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vmin(value))),
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"vmax" => Ok(Length::ViewportPercentage(ViewportPercentageLength::Vmax(value)))*/
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// Handle em, ex, rem, vw, vh, vmin, vmax
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_ => return Err(())
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fn parse_sum(input: &mut Parser) -> Result<CalcSumNode, ()> {
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let mut products = Vec::new();
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products.push(try!(Calc::parse_product(input)));
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loop {
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let next = input.next();
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match next {
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Ok(Token::Delim('+')) => {
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products.push(try!(Calc::parse_product(input)));
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}
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Ok(Token::Delim('-')) => {
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let mut right = try!(Calc::parse_product(input));
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right.values.push(CalcValueNode::Number(-1.));
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products.push(right);
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}
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Ok(_) => return Err(()),
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_ => break
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}
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}
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let sum = CalcSumNode { products: products };
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println!("Parsed sum {:?} ", sum);
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Ok(sum)
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}
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fn parse_product(input: &mut Parser) -> Result<CalcProductNode, ()> {
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let mut values = Vec::new();
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values.push(try!(Calc::parse_value(input)));
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loop {
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let position = input.position();
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let next = input.next();
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match next {
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Ok(Token::Delim('*')) => {
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values.push(try!(Calc::parse_value(input)));
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}
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Ok(Token::Delim('/')) => {
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if let Ok(Token::Number(ref value)) = input.next() {
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if value.value == 0. {
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return Err(());
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}
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values.push(CalcValueNode::Number(1. / value.value));
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} else {
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return Err(());
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}
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}
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_ => {
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input.reset(position);
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break
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}
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}
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}
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let sum = CalcProductNode { values: values };
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println!("Parsed product {:?} ", sum);
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Ok(sum)
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}
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fn parse_value(input: &mut Parser) -> Result<CalcValueNode, ()> {
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let next = input.next();
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match next {
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Ok(Token::Number(ref value)) => Ok(CalcValueNode::Number(value.value)),
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Ok(Token::Dimension(ref value, ref unit)) =>
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Length::parse_dimension(value.value, unit).map(CalcValueNode::Length),
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Ok(Token::Percentage(ref value)) =>
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Ok(CalcValueNode::Percentage(value.unit_value)),
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Ok(Token::ParenthesisBlock) => {
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let result = try!(input.parse_nested_block(Calc::parse_sum));
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Ok(CalcValueNode::Sum(box result))
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},
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Token::Percentage(ref value) =>
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self.percentage = Some(self.percentage.unwrap_or(0.) + value.unit_value),
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Token::Number(ref value) if value.value == 0. =>
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self.absolute = self.absolute.or(Some(Au(0))),
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_ => return Err(())
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};
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Ok(())
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_ => Err(())
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}
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}
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fn simplify_ast(node: CalcSumNode) -> Result<CalcSumNode, ()> {
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let mut simplified = Vec::new();
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for node in node.products {
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let node = try!(Calc::simplify_product(node));
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match node {
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CalcAstNode::Value(value) => {
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let product = CalcProductNode { values: vec!(value) };
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simplified.push(product);
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}
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_ => return Err(())
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}
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}
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Ok(CalcSumNode {products: simplified} )
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}
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fn simplify_product(node: CalcProductNode) -> Result<CalcAstNode, ()> {
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let mut multiplier = 1.;
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let mut node_with_unit: Option<CalcAstNode> = None;
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let mut node_hack: CalcAstNode;
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for node in node.values {
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node_hack = try!(Calc::simplify_value(node));
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if let CalcAstNode::Value(CalcValueNode::Number(n)) = node_hack {
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multiplier *= n;
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} else if node_with_unit.is_none() {
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node_with_unit = Some(node_hack);
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} else {
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return Err(());
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}
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}
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match node_with_unit {
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None => Ok(CalcAstNode::Value(CalcValueNode::Number(multiplier))),
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Some(CalcAstNode::Add(sum)) =>
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Ok(CalcAstNode::Add(CalcSumNode {
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products: sum.products
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.iter()
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.map(|p| Calc::multiply_product(p, multiplier))
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.collect()
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})),
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Some(CalcAstNode::Value(ref value)) =>
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Ok(CalcAstNode::Value(Calc::multiply_value(value, multiplier))),
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_ => unreachable!()
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}
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}
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fn multiply_product(node: &CalcProductNode, multiplier: CSSFloat) -> CalcProductNode {
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CalcProductNode {
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values: node.values
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.iter()
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.map(|v| Calc::multiply_value(v, multiplier))
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.collect()
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}
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}
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fn multiply_value(node: &CalcValueNode, multiplier: CSSFloat) -> CalcValueNode {
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match node {
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&CalcValueNode::Number(_) => unreachable!(),
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&CalcValueNode::Percentage(p) => CalcValueNode::Percentage(p * multiplier),
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&CalcValueNode::Sum(_) => unreachable!(),
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&CalcValueNode::Length(l) => CalcValueNode::Length(Calc::multiply_length(l, multiplier))
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}
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}
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fn multiply_length(length: Length, multiplier: CSSFloat) -> Length {
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match length {
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Length::Absolute(Au(au)) =>
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Length::Absolute(Au((au as CSSFloat * multiplier) as i32)),
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_ => panic!()
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}
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}
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fn simplify_sum(node: CalcSumNode) -> Result<CalcAstNode, ()> {
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let mut simplified = Vec::new();
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let length = node.products.len();
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for node in node.products {
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let node = try!(Calc::simplify_product(node));
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match node {
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CalcAstNode::Value(value) => {
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let product = CalcProductNode { values: vec!(value) };
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if length == 1 {
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return Ok(CalcAstNode::Multiply(product));
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}
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simplified.push(product);
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}
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CalcAstNode::Add(sum) => simplified.push_all(&sum.products),
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_ => return Err(())
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}
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}
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Ok(CalcAstNode::Add(CalcSumNode {products: simplified} ))
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}
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fn simplify_value(node: CalcValueNode) -> Result<CalcAstNode, ()> {
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match node {
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CalcValueNode::Sum(box sum) => Calc::simplify_sum(sum),
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node => Ok(CalcAstNode::Value(node))
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}
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}
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pub fn parse(input: &mut Parser) -> Result<Calc, ()> {
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let ast = try!(Calc::parse_sum(input));
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let ast = try!(Calc::simplify_sum(ast));
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let mut calc = Calc {
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absolute: None,
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font_relative: None,
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@ -408,14 +571,23 @@ pub mod specified {
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percentage: None,
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};
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try!(calc.parse_component(input));
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let operator = try!(input.next());
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match operator {
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Token::Delim('+') => (),
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_ => return Err(())
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};
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if let CalcAstNode::Add(ast) = ast {
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for value in ast.products {
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assert!(value.values.len() == 1);
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match value.values[0] {
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CalcValueNode::Percentage(p) =>
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calc.percentage = Some(calc.percentage.unwrap_or(0.) + p),
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CalcValueNode::Length(Length::Absolute(Au(au))) =>
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calc.absolute = Some(calc.absolute.unwrap_or(Au(0)) + Au(au)),
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//CalcValueNode::Length(Length::FontRelative(Au(au)))
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//calc.absolute = Some(calc.absolute.unwrap_or(0.) + au),
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_ => return Err(())
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}
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}
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} else {
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unreachable!()
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}
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try!(calc.parse_component(input));
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Ok(calc)
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}
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}
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