style: Fix container query evaluation on unsupported axis

We were falling back to viewport size, which is not what the spec says.

Differential Revision: https://phabricator.services.mozilla.com/D161132

components/style/queries/feature.rs

@@ -34,11 +34,13 @@ pub type KeywordParser = for<'a, 'i, 't> fn(
 #[allow(missing_docs)]
 pub enum Evaluator {
     Length(QueryFeatureGetter<CSSPixelLength>),
+    OptionalLength(QueryFeatureGetter<Option<CSSPixelLength>>),
     Integer(QueryFeatureGetter<u32>),
     Float(QueryFeatureGetter<f32>),
     BoolInteger(QueryFeatureGetter<bool>),
     /// A non-negative number ratio, such as the one from device-pixel-ratio.
     NumberRatio(QueryFeatureGetter<Ratio>),
+    OptionalNumberRatio(QueryFeatureGetter<Option<Ratio>>),
     /// A resolution.
     Resolution(QueryFeatureGetter<Resolution>),
     /// A keyword value.

components/style/queries/feature_expression.rs

@@ -591,6 +591,14 @@ impl QueryFeatureExpression {
                 self.kind
                     .evaluate(v, |v| expect!(Length, v).to_computed_value(context))
             },
+            Evaluator::OptionalLength(eval) => {
+                let v = match eval(context) {
+                    Some(v) => v,
+                    None => return false,
+                };
+                self.kind
+                    .evaluate(v, |v| expect!(Length, v).to_computed_value(context))
+            },
             Evaluator::Integer(eval) => {
                 let v = eval(context);
                 self.kind.evaluate(v, |v| *expect!(Integer, v))
@@ -608,6 +616,15 @@ impl QueryFeatureExpression {
                 self.kind
                     .evaluate(ratio, |v| expect!(NumberRatio, v).used_value())
             },
+            Evaluator::OptionalNumberRatio(eval) => {
+                let ratio = match eval(context) {
+                    Some(v) => v,
+                    None => return false,
+                };
+                // See above for subtleties here.
+                self.kind
+                    .evaluate(ratio, |v| expect!(NumberRatio, v).used_value())
+            },
             Evaluator::Resolution(eval) => {
                 let v = eval(context).dppx();
                 self.kind.evaluate(v, |v| {
@@ -686,7 +703,7 @@ impl QueryExpressionValue {
         input: &mut Parser<'i, 't>,
     ) -> Result<QueryExpressionValue, ParseError<'i>> {
         Ok(match for_feature.evaluator {
-            Evaluator::Length(..) => {
+            Evaluator::OptionalLength(..) | Evaluator::Length(..) => {
                 let length = Length::parse_non_negative(context, input)?;
                 QueryExpressionValue::Length(length)
             },
@@ -706,7 +723,7 @@ impl QueryExpressionValue {
                 let number = Number::parse(context, input)?;
                 QueryExpressionValue::Float(number.get())
             },
-            Evaluator::NumberRatio(..) => {
+            Evaluator::OptionalNumberRatio(..) | Evaluator::NumberRatio(..) => {
                 use crate::values::specified::Ratio as SpecifiedRatio;
                 let ratio = SpecifiedRatio::parse(context, input)?;
                 QueryExpressionValue::NumberRatio(Ratio::new(ratio.0.get(), ratio.1.get()))

components/style/stylesheets/container_rule.rs

@@ -261,51 +261,44 @@ pub struct ContainerInfo {
     wm: WritingMode,
 }
 
-fn get_container(context: &Context) -> ContainerInfo {
-    if let Some(ref info) = context.container_info {
-        return info.clone();
-    }
-    ContainerInfo {
-        size: context.device().au_viewport_size(),
-        wm: WritingMode::horizontal_tb(),
-    }
+fn eval_width(context: &Context) -> Option<CSSPixelLength> {
+    let info = context.container_info.as_ref()?;
+    Some(CSSPixelLength::new(info.size.width.to_f32_px()))
 }
 
-fn eval_width(context: &Context) -> CSSPixelLength {
-    let info = get_container(context);
-    CSSPixelLength::new(info.size.width.to_f32_px())
+fn eval_height(context: &Context) -> Option<CSSPixelLength> {
+    let info = context.container_info.as_ref()?;
+    Some(CSSPixelLength::new(info.size.height.to_f32_px()))
 }
 
-fn eval_height(context: &Context) -> CSSPixelLength {
-    let info = get_container(context);
-    CSSPixelLength::new(info.size.height.to_f32_px())
-}
-
-fn eval_inline_size(context: &Context) -> CSSPixelLength {
-    let info = get_container(context);
-    CSSPixelLength::new(
+fn eval_inline_size(context: &Context) -> Option<CSSPixelLength> {
+    let info = context.container_info.as_ref()?;
+    Some(CSSPixelLength::new(
         LogicalSize::from_physical(info.wm, info.size)
             .inline
             .to_f32_px(),
-    )
+    ))
 }
 
-fn eval_block_size(context: &Context) -> CSSPixelLength {
-    let info = get_container(context);
-    CSSPixelLength::new(
+fn eval_block_size(context: &Context) -> Option<CSSPixelLength> {
+    let info = context.container_info.as_ref()?;
+    Some(CSSPixelLength::new(
         LogicalSize::from_physical(info.wm, info.size)
             .block
             .to_f32_px(),
-    )
+    ))
 }
 
-fn eval_aspect_ratio(context: &Context) -> Ratio {
-    let info = get_container(context);
-    Ratio::new(info.size.width.0 as f32, info.size.height.0 as f32)
+fn eval_aspect_ratio(context: &Context) -> Option<Ratio> {
+    let info = context.container_info.as_ref()?;
+    Some(Ratio::new(info.size.width.0 as f32, info.size.height.0 as f32))
 }
 
 fn eval_orientation(context: &Context, value: Option<Orientation>) -> bool {
-    let info = get_container(context);
+    let info = match context.container_info.as_ref() {
+        Some(info) => info,
+        None => return false,
+    };
     Orientation::eval(info.size, value)
 }
 
@@ -316,31 +309,31 @@ pub static CONTAINER_FEATURES: [QueryFeatureDescription; 6] = [
     feature!(
         atom!("width"),
         AllowsRanges::Yes,
-        Evaluator::Length(eval_width),
+        Evaluator::OptionalLength(eval_width),
         FeatureFlags::CONTAINER_REQUIRES_WIDTH_AXIS,
     ),
     feature!(
         atom!("height"),
         AllowsRanges::Yes,
-        Evaluator::Length(eval_height),
+        Evaluator::OptionalLength(eval_height),
         FeatureFlags::CONTAINER_REQUIRES_HEIGHT_AXIS,
     ),
     feature!(
         atom!("inline-size"),
         AllowsRanges::Yes,
-        Evaluator::Length(eval_inline_size),
+        Evaluator::OptionalLength(eval_inline_size),
         FeatureFlags::CONTAINER_REQUIRES_INLINE_AXIS,
     ),
     feature!(
         atom!("block-size"),
         AllowsRanges::Yes,
-        Evaluator::Length(eval_block_size),
+        Evaluator::OptionalLength(eval_block_size),
         FeatureFlags::CONTAINER_REQUIRES_BLOCK_AXIS,
     ),
     feature!(
         atom!("aspect-ratio"),
         AllowsRanges::Yes,
-        Evaluator::NumberRatio(eval_aspect_ratio),
+        Evaluator::OptionalNumberRatio(eval_aspect_ratio),
         // XXX from_bits_truncate is const, but the pipe operator isn't, so this
         // works around it.
         FeatureFlags::from_bits_truncate(