Enable min-content, max-content, fit-content and stretch (#33492)

For the sizing properties.

We don't actually support them yet, just treating them as
the initial value.

Signed-off-by: Oriol Brufau <obrufau@igalia.com>
Co-authored-by: Martin Robinson <mrobinson@igalia.com>

components/layout/block.rs

@@ -419,24 +419,24 @@ impl CandidateBSizeIterator {
         // If that is not determined yet by the time we need to resolve
         // `min-height` and `max-height`, percentage values are ignored.
 
-        let block_size = match fragment.style.content_block_size() {
-            Size::Auto => MaybeAuto::Auto,
-            Size::LengthPercentage(ref lp) => {
-                MaybeAuto::from_option(lp.maybe_to_used_value(block_container_block_size))
-            },
-        };
+        let block_size = MaybeAuto::from_option(
+            fragment
+                .style
+                .content_block_size()
+                .maybe_to_used_value(block_container_block_size),
+        );
 
-        let max_block_size = match fragment.style.max_block_size() {
-            MaxSize::None => None,
-            MaxSize::LengthPercentage(ref lp) => lp.maybe_to_used_value(block_container_block_size),
-        };
+        let max_block_size = fragment
+            .style
+            .max_block_size()
+            .maybe_to_used_value(block_container_block_size);
 
-        let min_block_size = match fragment.style.min_block_size() {
-            Size::Auto => MaybeAuto::Auto,
-            Size::LengthPercentage(ref lp) => {
-                MaybeAuto::from_option(lp.maybe_to_used_value(block_container_block_size))
-            },
-        }
+        let min_block_size = MaybeAuto::from_option(
+            fragment
+                .style
+                .min_block_size()
+                .maybe_to_used_value(block_container_block_size),
+        )
         .specified_or_zero();
 
         // If the style includes `box-sizing: border-box`, subtract the border and padding.
@@ -1402,7 +1402,8 @@ impl BlockFlow {
         let content_block_size = self.fragment.style().content_block_size();
 
         match content_block_size {
-            Size::Auto => {
+            Size::LengthPercentage(ref lp) => lp.maybe_to_used_value(containing_block_size),
+            _ => {
                 let container_size = containing_block_size?;
                 let (block_start, block_end) = {
                     let position = self.fragment.style().logical_position();
@@ -1437,7 +1438,6 @@ impl BlockFlow {
                     (_, _) => None,
                 }
             },
-            Size::LengthPercentage(ref lp) => lp.maybe_to_used_value(containing_block_size),
         }
     }
 
@@ -2167,10 +2167,13 @@ impl Flow for BlockFlow {
         // If this block has a fixed width, just use that for the minimum and preferred width,
         // rather than bubbling up children inline width.
         // FIXME(emilio): This should probably be writing-mode-aware.
-        let consult_children = match self.fragment.style().get_position().width {
-            Size::Auto => true,
-            Size::LengthPercentage(ref lp) => lp.maybe_to_used_value(None).is_none(),
-        };
+        let consult_children = self
+            .fragment
+            .style()
+            .get_position()
+            .width
+            .maybe_to_used_value(None)
+            .is_none();
         self.bubble_inline_sizes_for_block(consult_children);
         self.fragment
             .restyle_damage

components/layout/flex.rs

@@ -48,11 +48,11 @@ impl AxisSize {
     /// containing block size, min constraint, and max constraint
     pub fn new(size: &Size, content_size: Option<Au>, min: &Size, max: &MaxSize) -> AxisSize {
         match size {
-            Size::Auto => AxisSize::MinMax(SizeConstraint::new(content_size, min, max, None)),
             Size::LengthPercentage(ref lp) => match lp.maybe_to_used_value(content_size) {
                 Some(length) => AxisSize::Definite(length),
                 None => AxisSize::Infinite,
             },
+            _ => AxisSize::MinMax(SizeConstraint::new(content_size, min, max, None)),
         }
     }
 }
@@ -72,10 +72,7 @@ fn from_flex_basis(flex_basis: &FlexBasis, main_length: &Size, containing_length
         _ => width,
     };
 
-    match width {
-        Size::Auto => MaybeAuto::Auto,
-        Size::LengthPercentage(ref lp) => MaybeAuto::Specified(lp.to_used_value(containing_length)),
-    }
+    MaybeAuto::from_option(width.to_used_value(containing_length))
 }
 
 /// Represents a child in a flex container. Most fields here are used in

components/layout/floats.rs

@@ -10,7 +10,6 @@ use log::debug;
 use serde::Serialize;
 use style::computed_values::float::T as StyleFloat;
 use style::logical_geometry::{LogicalRect, LogicalSize, WritingMode};
-use style::values::computed::Size;
 
 use crate::block::FormattingContextType;
 use crate::flow::{Flow, FlowFlags, GetBaseFlow, ImmutableFlowUtils};
@@ -551,12 +550,8 @@ impl SpeculatedFloatPlacement {
             // traversal logic will know that objects later in the document
             // might flow around this float.
             let inline_size = flow.as_block().fragment.style.content_inline_size();
-            let fixed = match inline_size {
-                Size::Auto => false,
-                Size::LengthPercentage(ref lp) => {
-                    lp.0.is_definitely_zero() || lp.0.maybe_to_used_value(None).is_some()
-                },
-            };
+            let fixed =
+                inline_size.is_definitely_zero() || inline_size.maybe_to_used_value(None).is_some();
             if !fixed {
                 float_inline_size = Au::from_px(1)
             }

components/layout/fragment.rs

@@ -50,7 +50,7 @@ use style::selector_parser::RestyleDamage;
 use style::servo::restyle_damage::ServoRestyleDamage;
 use style::str::char_is_whitespace;
 use style::values::computed::counters::ContentItem;
-use style::values::computed::{Length, Size, VerticalAlign};
+use style::values::computed::{Length, VerticalAlign};
 use style::values::generics::box_::{Perspective, VerticalAlignKeyword};
 use style::values::generics::transform;
 use webrender_api::units::LayoutTransform;
@@ -1642,11 +1642,7 @@ impl Fragment {
             SpecificFragmentInfo::Canvas(_) |
             SpecificFragmentInfo::Iframe(_) |
             SpecificFragmentInfo::Svg(_) => {
-                let inline_size = match self.style.content_inline_size() {
-                    Size::Auto => None,
-                    Size::LengthPercentage(ref lp) => lp.maybe_to_used_value(None),
-                };
-
+                let inline_size = self.style.content_inline_size().maybe_to_used_value(None);
                 let mut inline_size = inline_size.unwrap_or_else(|| {
                     // We have to initialize the `border_padding` field first to make
                     // the size constraints work properly.

components/layout/model.rs

@@ -147,14 +147,12 @@ impl MarginCollapseInfo {
     ) -> (CollapsibleMargins, Au) {
         let state = match self.state {
             MarginCollapseState::AccumulatingCollapsibleTopMargin => {
+                let content_block_size = fragment.style().content_block_size();
                 may_collapse_through = may_collapse_through &&
-                    match fragment.style().content_block_size() {
-                        Size::Auto => true,
-                        Size::LengthPercentage(ref lp) => {
-                            lp.is_definitely_zero() ||
-                                lp.maybe_to_used_value(containing_block_size).is_none()
-                        },
-                    };
+                    content_block_size.is_definitely_zero() ||
+                    content_block_size
+                        .maybe_to_used_value(containing_block_size)
+                        .is_none();
 
                 if may_collapse_through {
                     if fragment.style.min_block_size().is_auto() ||
@@ -522,12 +520,7 @@ impl MaybeAuto {
 ///
 /// `style_length`: content size as given in the CSS.
 pub fn style_length(style_length: &Size, container_size: Option<Au>) -> MaybeAuto {
-    match style_length {
-        Size::Auto => MaybeAuto::Auto,
-        Size::LengthPercentage(ref lp) => {
-            MaybeAuto::from_option(lp.0.maybe_to_used_value(container_size))
-        },
-    }
+    MaybeAuto::from_option(style_length.maybe_to_used_value(container_size))
 }
 
 #[inline]
@@ -595,17 +588,10 @@ impl SizeConstraint {
         max_size: &MaxSize,
         border: Option<Au>,
     ) -> SizeConstraint {
-        let mut min_size = match min_size {
-            Size::Auto => Au(0),
-            Size::LengthPercentage(ref lp) => {
-                lp.maybe_to_used_value(container_size).unwrap_or(Au(0))
-            },
-        };
-
-        let mut max_size = match max_size {
-            MaxSize::None => None,
-            MaxSize::LengthPercentage(ref lp) => lp.maybe_to_used_value(container_size),
-        };
+        let mut min_size = min_size
+            .maybe_to_used_value(container_size)
+            .unwrap_or(Au(0));
+        let mut max_size = max_size.maybe_to_used_value(container_size);
 
         // Make sure max size is not smaller than min size.
         max_size = max_size.map(|x| max(x, min_size));

components/layout/multicol.rs

@@ -15,7 +15,7 @@ use log::{debug, trace};
 use style::logical_geometry::LogicalSize;
 use style::properties::ComputedValues;
 use style::values::computed::length::{
-    MaxSize, NonNegativeLengthOrAuto, NonNegativeLengthPercentageOrNormal, Size,
+    NonNegativeLengthOrAuto, NonNegativeLengthPercentageOrNormal,
 };
 use style::values::generics::column::ColumnCount;
 
@@ -167,14 +167,10 @@ impl Flow for MulticolFlow {
             this_fragment_is_empty: true,
             available_block_size: {
                 let style = &self.block_flow.fragment.style;
-                let size = match style.content_block_size() {
-                    Size::Auto => None,
-                    Size::LengthPercentage(ref lp) => lp.maybe_to_used_value(None),
-                };
-                let size = size.or_else(|| match style.max_block_size() {
-                    MaxSize::None => None,
-                    MaxSize::LengthPercentage(ref lp) => lp.maybe_to_used_value(None),
-                });
+                let size = style
+                    .content_block_size()
+                    .maybe_to_used_value(None)
+                    .or_else(|| style.max_block_size().maybe_to_used_value(None));
 
                 size.unwrap_or_else(|| {
                     // FIXME: do column balancing instead

components/layout/table.rs

@@ -307,17 +307,14 @@ impl Flow for TableFlow {
             for specified_inline_size in &kid.as_mut_table_colgroup().inline_sizes {
                 self.column_intrinsic_inline_sizes
                     .push(ColumnIntrinsicInlineSize {
-                        minimum_length: match *specified_inline_size {
-                            Size::Auto => Au(0),
-                            Size::LengthPercentage(ref lp) => {
-                                lp.maybe_to_used_value(None).unwrap_or(Au(0))
-                            },
-                        },
+                        minimum_length: specified_inline_size
+                            .maybe_to_used_value(None)
+                            .unwrap_or(Au(0)),
                         percentage: match *specified_inline_size {
-                            Size::Auto => 0.0,
                             Size::LengthPercentage(ref lp) => {
                                 lp.0.to_percentage().map_or(0.0, |p| p.0)
                             },
+                            _ => 0.0,
                         },
                         preferred: Au(0),
                         constrained: false,

components/layout/table_cell.rs

@@ -14,7 +14,6 @@ use script_layout_interface::wrapper_traits::ThreadSafeLayoutNode;
 use serde::Serialize;
 use style::logical_geometry::{LogicalMargin, LogicalRect, LogicalSize, WritingMode};
 use style::properties::ComputedValues;
-use style::values::computed::length::Size;
 use style::values::computed::Color;
 use style::values::generics::box_::{VerticalAlign, VerticalAlignKeyword};
 use style::values::specified::BorderStyle;
@@ -206,10 +205,13 @@ impl Flow for TableCellFlow {
         );
 
         self.block_flow.bubble_inline_sizes_for_block(true);
-        let specified_inline_size = match self.block_flow.fragment.style().content_inline_size() {
-            Size::Auto => Au(0),
-            Size::LengthPercentage(ref lp) => lp.to_used_value(Au(0)),
-        };
+        let specified_inline_size = self
+            .block_flow
+            .fragment
+            .style()
+            .content_inline_size()
+            .to_used_value(Au(0))
+            .unwrap_or(Au(0));
 
         if self
             .block_flow

components/layout/table_row.rs

@@ -432,21 +432,17 @@ impl Flow for TableRowFlow {
                 // Collect minimum and preferred inline-sizes of the cell for automatic table layout
                 // calculation.
                 let child_base = kid.mut_base();
+                let resolved_child_specified_inline_size =
+                    child_specified_inline_size.maybe_to_used_value(None);
                 let child_column_inline_size = ColumnIntrinsicInlineSize {
-                    minimum_length: match child_specified_inline_size {
-                        Size::Auto => None,
-                        Size::LengthPercentage(ref lp) => lp.0.maybe_to_used_value(None),
-                    }
-                    .unwrap_or(child_base.intrinsic_inline_sizes.minimum_inline_size),
+                    minimum_length: resolved_child_specified_inline_size
+                        .unwrap_or(child_base.intrinsic_inline_sizes.minimum_inline_size),
                     percentage: match child_specified_inline_size {
-                        Size::Auto => 0.0,
                         Size::LengthPercentage(ref lp) => lp.0.to_percentage().map_or(0.0, |p| p.0),
+                        _ => 0.0,
                     },
                     preferred: child_base.intrinsic_inline_sizes.preferred_inline_size,
-                    constrained: match child_specified_inline_size {
-                        Size::Auto => false,
-                        Size::LengthPercentage(ref lp) => lp.0.maybe_to_used_value(None).is_some(),
-                    },
+                    constrained: resolved_child_specified_inline_size.is_some(),
                 };
                 min_inline_size += child_column_inline_size.minimum_length;
                 pref_inline_size += child_column_inline_size.preferred;

components/layout/table_wrapper.rs

@@ -848,25 +848,30 @@ fn initial_computed_inline_size(
     preferred_width_of_all_columns: Au,
     table_border_padding: Au,
 ) -> MaybeAuto {
-    match block.fragment.style.content_inline_size() {
-        Size::Auto => {
-            if preferred_width_of_all_columns + table_border_padding <= containing_block_inline_size
-            {
-                MaybeAuto::Specified(preferred_width_of_all_columns + table_border_padding)
-            } else if minimum_width_of_all_columns > containing_block_inline_size {
-                MaybeAuto::Specified(minimum_width_of_all_columns)
-            } else {
-                MaybeAuto::Auto
-            }
-        },
-        Size::LengthPercentage(ref lp) => {
-            let used = lp.to_used_value(containing_block_inline_size);
-            MaybeAuto::Specified(max(
-                used - table_border_padding,
-                minimum_width_of_all_columns,
-            ))
-        },
-    }
+    block
+        .fragment
+        .style
+        .content_inline_size()
+        .to_used_value(containing_block_inline_size)
+        .map_or_else(
+            || {
+                if preferred_width_of_all_columns + table_border_padding <=
+                    containing_block_inline_size
+                {
+                    MaybeAuto::Specified(preferred_width_of_all_columns + table_border_padding)
+                } else if minimum_width_of_all_columns > containing_block_inline_size {
+                    MaybeAuto::Specified(minimum_width_of_all_columns)
+                } else {
+                    MaybeAuto::Auto
+                }
+            },
+            |used| {
+                MaybeAuto::Specified(max(
+                    used - table_border_padding,
+                    minimum_width_of_all_columns,
+                ))
+            },
+        )
 }
 
 struct Table {

components/layout_2020/flexbox/layout.rs

@@ -2359,9 +2359,10 @@ impl FlexItemBox {
                     },
                 }
             },
-            FlexBasis::Size(Size::Auto) => {
+            FlexBasis::Size(_) => {
                 // “When specified on a flex item, the `auto` keyword retrieves
                 //  the value of the main size property as the used `flex-basis`.”
+                // TODO(#32853): Handle other intrinsic keywords.
                 match content_box_size.main {
                     AuOrAuto::LengthPercentage(length) => FlexBasis::Size(length),
                     // “If that value is itself `auto`, then the used value is `content`.”

components/layout_2020/flow/mod.rs

@@ -168,8 +168,8 @@ impl BlockLevelBox {
             return false;
         }
 
-        if !block_size_is_zero_or_auto(style.content_block_size(), containing_block) ||
-            !block_size_is_zero_or_auto(style.min_block_size(), containing_block) ||
+        if !block_size_is_zero_or_intrinsic(style.content_block_size(), containing_block) ||
+            !block_size_is_zero_or_intrinsic(style.min_block_size(), containing_block) ||
             pbm.padding_border_sums.block != Au::zero()
         {
             return false;
@@ -877,8 +877,8 @@ fn layout_in_flow_non_replaced_block_level_same_formatting_context(
 
     let collapsed_through = collapsible_margins_in_children.collapsed_through &&
         pbm.padding_border_sums.block == Au::zero() &&
-        block_size_is_zero_or_auto(computed_block_size, containing_block) &&
-        block_size_is_zero_or_auto(style.min_block_size(), containing_block);
+        block_size_is_zero_or_intrinsic(computed_block_size, containing_block) &&
+        block_size_is_zero_or_intrinsic(style.min_block_size(), containing_block);
     block_margins_collapsed_with_children.collapsed_through = collapsed_through;
 
     let end_margin_can_collapse_with_children = collapsed_through ||
@@ -1872,9 +1872,9 @@ impl<'container> PlacementState<'container> {
     }
 }
 
-fn block_size_is_zero_or_auto(size: &Size, containing_block: &ContainingBlock) -> bool {
+fn block_size_is_zero_or_intrinsic(size: &Size, containing_block: &ContainingBlock) -> bool {
     match size {
-        Size::Auto => true,
+        Size::Auto | Size::MinContent | Size::MaxContent | Size::FitContent | Size::Stretch => true,
         Size::LengthPercentage(ref lp) => {
             // TODO: Should this resolve definite percentages? Blink does it, Gecko and WebKit don't.
             lp.is_definitely_zero() ||

components/layout_2020/style_ext.rs

@@ -341,7 +341,11 @@ impl ComputedValuesExt for ComputedValues {
         fn unwrap(max_size: &MaxSize<NonNegativeLengthPercentage>) -> Option<&LengthPercentage> {
             match max_size {
                 MaxSize::LengthPercentage(length) => Some(&length.0),
-                MaxSize::None => None,
+                MaxSize::None |
+                MaxSize::MinContent |
+                MaxSize::MaxContent |
+                MaxSize::FitContent |
+                MaxSize::Stretch => None,
             }
         }
         let position = self.get_position();
@@ -997,7 +1001,9 @@ impl From<stylo::Display> for Display {
 fn size_to_length(size: &Size) -> LengthPercentageOrAuto {
     match size {
         Size::LengthPercentage(length) => LengthPercentageOrAuto::LengthPercentage(&length.0),
-        Size::Auto => LengthPercentageOrAuto::Auto,
+        Size::Auto | Size::MinContent | Size::MaxContent | Size::FitContent | Size::Stretch => {
+            LengthPercentageOrAuto::Auto
+        },
     }
 }