style: Serialize NaN and infinity numbers

Added NaN/inf serialization of <number> and changed calc() code to not
remove NaN/infinity in code using it.

This change is unfortunately imperfect as some things using <number>
still refuse to serialize NaN/infinity for some reason (scale()?), but
this bug/patch is just for <number> so leaving that out of scope for
this.

Also added new WPT test file for number NaN/inf serialization based
on existing serialization tests (all pass already!).

5 other WPT subtests now newly pass.

Differential Revision: https://phabricator.services.mozilla.com/D178587

components/style/values/mod.rs

@@ -99,6 +99,14 @@ fn nan_inf_enabled() -> bool {
     return false;
 }
 
+/// Serialize a number with calc, and NaN/infinity handling (if enabled)
+pub fn serialize_number<W>(v: f32, was_calc: bool, dest: &mut CssWriter<W>) -> fmt::Result
+where
+    W: Write,
+{
+    serialize_specified_dimension(v, "", was_calc, dest)
+}
+
 /// Serialize a specified dimension with unit, calc, and NaN/infinity handling (if enabled)
 pub fn serialize_specified_dimension<W>(
     v: f32,
@@ -120,11 +128,15 @@ where
         // requires an expression like calc(infinity * 1px)."
 
         if v.is_nan() {
-            dest.write_str("NaN * 1")?;
+            dest.write_str("NaN")?;
         } else if v == f32::INFINITY {
-            dest.write_str("infinity * 1")?;
+            dest.write_str("infinity")?;
         } else if v == f32::NEG_INFINITY {
-            dest.write_str("-infinity * 1")?;
+            dest.write_str("-infinity")?;
+        }
+
+        if !unit.is_empty() {
+            dest.write_str(" * 1")?;
         }
     } else {
         v.to_css(dest)?;

components/style/values/specified/calc.rs

@@ -12,7 +12,7 @@ use crate::values::generics::calc::{MinMaxOp, ModRemOp, RoundingStrategy, SortKe
 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 crate::values::{serialize_number, serialize_percentage, CSSFloat, CSSInteger};
 use cssparser::{AngleOrNumber, CowRcStr, NumberOrPercentage, Parser, Token};
 use smallvec::SmallVec;
 use std::cmp;
@@ -131,9 +131,9 @@ impl ToCss for Leaf {
     {
         match *self {
             Self::Length(ref l) => l.to_css(dest),
-            Self::Number(ref n) => n.to_css(dest),
+            Self::Number(n) => serialize_number(n, /* was_calc = */ false, dest),
             Self::Resolution(ref r) => r.to_css(dest),
-            Self::Percentage(p) => crate::values::serialize_percentage(p, dest),
+            Self::Percentage(p) => serialize_percentage(p, dest),
             Self::Angle(ref a) => a.to_css(dest),
             Self::Time(ref t) => t.to_css(dest),
         }
@@ -887,10 +887,16 @@ impl CalcNode {
 
     /// Tries to simplify this expression into a `<number>` value.
     fn to_number(&self) -> Result<CSSFloat, ()> {
-        self.resolve(|leaf| match *leaf {
+        let number = self.resolve(|leaf| match *leaf {
             Leaf::Number(n) => Ok(n),
             _ => Err(()),
-        })
+        })?;
+        let result = if nan_inf_enabled() {
+            number
+        } else {
+            crate::values::normalize(number)
+        };
+        Ok(result)
     }
 
     /// Tries to simplify this expression into a `<percentage>` value.
@@ -992,7 +998,6 @@ impl CalcNode {
     ) -> 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))
     }
 

components/style/values/specified/mod.rs

@@ -16,8 +16,8 @@ use super::generics::{self, GreaterThanOrEqualToOne, NonNegative};
 use super::{CSSFloat, CSSInteger};
 use crate::context::QuirksMode;
 use crate::parser::{Parse, ParserContext};
-use crate::values::serialize_atom_identifier;
 use crate::values::specified::calc::CalcNode;
+use crate::values::{serialize_atom_identifier, serialize_number};
 use crate::{Atom, Namespace, One, Prefix, Zero};
 use cssparser::{Parser, Token};
 use std::fmt::{self, Write};
@@ -196,15 +196,15 @@ fn parse_number_with_clamping_mode<'i, 't>(
     match *input.next()? {
         Token::Number { value, .. } if clamping_mode.is_ok(context.parsing_mode, value) => {
             Ok(Number {
-                value: value.min(f32::MAX).max(f32::MIN),
+                value,
                 calc_clamping_mode: None,
             })
         },
         Token::Function(ref name) => {
             let function = CalcNode::math_function(context, name, location)?;
-            let result = CalcNode::parse_number(context, input, function)?;
+            let value = CalcNode::parse_number(context, input, function)?;
             Ok(Number {
-                value: result.min(f32::MAX).max(f32::MIN),
+                value,
                 calc_clamping_mode: Some(clamping_mode),
             })
         },
@@ -264,8 +264,12 @@ impl Number {
     /// Returns the numeric value, clamped if needed.
     #[inline]
     pub fn get(&self) -> f32 {
-        self.calc_clamping_mode
-            .map_or(self.value, |mode| mode.clamp(self.value))
+        crate::values::normalize(
+            self.calc_clamping_mode
+                .map_or(self.value, |mode| mode.clamp(self.value)),
+        )
+        .min(f32::MAX)
+        .max(f32::MIN)
     }
 
     #[allow(missing_docs)]
@@ -316,14 +320,7 @@ impl ToCss for Number {
     where
         W: Write,
     {
-        if self.calc_clamping_mode.is_some() {
-            dest.write_str("calc(")?;
-        }
-        self.value.to_css(dest)?;
-        if self.calc_clamping_mode.is_some() {
-            dest.write_char(')')?;
-        }
-        Ok(())
+        serialize_number(self.value, self.calc_clamping_mode.is_some(), dest)
     }
 }