Auto merge of #25888 - ferjm:text.decoration.2020, r=nox

Partial text decoration support for layout 2020

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #25166
- [X] There are tests for these changes

components/layout_2020/flow/construct.rs

@@ -19,6 +19,7 @@ use servo_arc::Arc;
 use std::convert::{TryFrom, TryInto};
 use style::properties::ComputedValues;
 use style::selector_parser::PseudoElement;
+use style::values::specified::text::TextDecorationLine;
 
 impl BlockFormattingContext {
     pub fn construct<'dom>(
@@ -27,9 +28,16 @@ impl BlockFormattingContext {
         style: &Arc<ComputedValues>,
         contents: NonReplacedContents,
         content_sizes: ContentSizesRequest,
+        propagated_text_decoration_line: TextDecorationLine,
     ) -> (Self, BoxContentSizes) {
-        let (contents, contains_floats, inline_content_sizes) =
-            BlockContainer::construct(context, node, style, contents, content_sizes);
+        let (contents, contains_floats, inline_content_sizes) = BlockContainer::construct(
+            context,
+            node,
+            style,
+            contents,
+            content_sizes,
+            propagated_text_decoration_line,
+        );
         // FIXME: add contribution to `inline_content_sizes` of floats in this formatting context
         // https://dbaron.org/css/intrinsic/#intrinsic
         let bfc = Self {
@@ -52,6 +60,7 @@ enum BlockLevelCreator {
     Independent {
         display_inside: DisplayInside,
         contents: Contents,
+        propagated_text_decoration_line: TextDecorationLine,
     },
     OutOfFlowAbsolutelyPositionedBox {
         display_inside: DisplayInside,
@@ -72,7 +81,7 @@ enum BlockLevelCreator {
 /// Deferring allows using rayon’s `into_par_iter`.
 enum IntermediateBlockContainer {
     InlineFormattingContext(InlineFormattingContext),
-    Deferred(NonReplacedContents),
+    Deferred(NonReplacedContents, TextDecorationLine),
 }
 
 /// A builder for a block container.
@@ -140,13 +149,16 @@ impl BlockContainer {
         block_container_style: &Arc<ComputedValues>,
         contents: NonReplacedContents,
         content_sizes: ContentSizesRequest,
+        propagated_text_decoration_line: TextDecorationLine,
     ) -> (BlockContainer, ContainsFloats, BoxContentSizes) {
+        let text_decoration_line =
+            propagated_text_decoration_line | block_container_style.clone_text_decoration_line();
         let mut builder = BlockContainerBuilder {
             context,
             root,
             block_container_style,
             block_level_boxes: Vec::new(),
-            ongoing_inline_formatting_context: InlineFormattingContext::default(),
+            ongoing_inline_formatting_context: InlineFormattingContext::new(text_decoration_line),
             ongoing_inline_boxes_stack: Vec::new(),
             anonymous_style: None,
             contains_floats: ContainsFloats::No,
@@ -439,6 +451,8 @@ where
                     display_inside,
                     contents,
                     ContentSizesRequest::inline_if(!style.inline_size_is_length()),
+                    // Text decorations are not propagated to atomic inline-level descendants.
+                    TextDecorationLine::NONE,
                 ),
             ))
         };
@@ -494,6 +508,9 @@ where
                 .push(ArcRefCell::new(fragmented_inline));
         }
 
+        let propagated_text_decoration_line =
+            self.ongoing_inline_formatting_context.text_decoration_line;
+
         // We found a block level element, so the ongoing inline formatting
         // context needs to be ended.
         self.end_ongoing_inline_formatting_context();
@@ -501,11 +518,12 @@ where
         let kind = match contents.try_into() {
             Ok(contents) => match display_inside {
                 DisplayInside::Flow => BlockLevelCreator::SameFormattingContextBlock(
-                    IntermediateBlockContainer::Deferred(contents),
+                    IntermediateBlockContainer::Deferred(contents, propagated_text_decoration_line),
                 ),
                 _ => BlockLevelCreator::Independent {
                     display_inside,
                     contents: contents.into(),
+                    propagated_text_decoration_line,
                 },
             },
             Err(contents) => {
@@ -513,6 +531,7 @@ where
                 BlockLevelCreator::Independent {
                     display_inside,
                     contents,
+                    propagated_text_decoration_line,
                 }
             },
         };
@@ -680,6 +699,7 @@ where
             BlockLevelCreator::Independent {
                 display_inside,
                 contents,
+                propagated_text_decoration_line,
             } => {
                 let content_sizes = ContentSizesRequest::inline_if(
                     max_assign_in_flow_outer_content_sizes_to.is_some() &&
@@ -692,6 +712,7 @@ where
                     display_inside,
                     contents,
                     content_sizes,
+                    propagated_text_decoration_line,
                 );
                 if let Some(to) = max_assign_in_flow_outer_content_sizes_to {
                     to.max_assign(&contents.content_sizes.outer_inline(&contents.style))
@@ -742,8 +763,15 @@ impl IntermediateBlockContainer {
         content_sizes: ContentSizesRequest,
     ) -> (BlockContainer, ContainsFloats, BoxContentSizes) {
         match self {
-            IntermediateBlockContainer::Deferred(contents) => {
-                BlockContainer::construct(context, node, style, contents, content_sizes)
+            IntermediateBlockContainer::Deferred(contents, propagated_text_decoration_line) => {
+                BlockContainer::construct(
+                    context,
+                    node,
+                    style,
+                    contents,
+                    content_sizes,
+                    propagated_text_decoration_line,
+                )
             },
             IntermediateBlockContainer::InlineFormattingContext(ifc) => {
                 let content_sizes = content_sizes.compute(|| ifc.inline_content_sizes(context));

components/layout_2020/flow/float.rs

@@ -9,6 +9,7 @@ use crate::sizing::ContentSizesRequest;
 use crate::style_ext::{ComputedValuesExt, DisplayInside};
 use servo_arc::Arc;
 use style::properties::ComputedValues;
+use style::values::specified::text::TextDecorationLine;
 
 #[derive(Debug, Serialize)]
 pub(crate) struct FloatBox {
@@ -43,6 +44,8 @@ impl FloatBox {
                 display_inside,
                 contents,
                 content_sizes,
+                // Text decorations are not propagated to any out-of-flow descendants
+                TextDecorationLine::NONE,
             ),
         }
     }

components/layout_2020/flow/inline.rs

@@ -9,7 +9,7 @@ use crate::flow::FlowLayout;
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::{
     AbsoluteOrFixedPositionedFragment, AnonymousFragment, BoxFragment, CollapsedBlockMargins,
-    DebugId, Fragment, TextFragment,
+    DebugId, FontMetrics, Fragment, TextFragment,
 };
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::positioned::{
@@ -26,12 +26,14 @@ use style::dom::OpaqueNode;
 use style::properties::ComputedValues;
 use style::values::computed::{Length, LengthPercentage, Percentage};
 use style::values::specified::text::TextAlignKeyword;
+use style::values::specified::text::TextDecorationLine;
 use style::Zero;
 use webrender_api::FontInstanceKey;
 
 #[derive(Debug, Default, Serialize)]
 pub(crate) struct InlineFormattingContext {
     pub(super) inline_level_boxes: Vec<ArcRefCell<InlineLevelBox>>,
+    pub(super) text_decoration_line: TextDecorationLine,
 }
 
 #[derive(Debug, Serialize)]
@@ -68,6 +70,11 @@ struct InlineNestingLevelState<'box_tree> {
     inline_start: Length,
     max_block_size_of_fragments_so_far: Length,
     positioning_context: Option<PositioningContext>,
+    /// Indicates whether this nesting level have text decorations in effect.
+    /// From https://drafts.csswg.org/css-text-decor/#line-decoration
+    // "When specified on or propagated to a block container that establishes
+    //  an IFC..."
+    text_decoration_line: TextDecorationLine,
 }
 
 struct PartialInlineBoxFragment<'box_tree> {
@@ -122,6 +129,13 @@ struct Lines {
 }
 
 impl InlineFormattingContext {
+    pub(super) fn new(text_decoration_line: TextDecorationLine) -> InlineFormattingContext {
+        InlineFormattingContext {
+            inline_level_boxes: Default::default(),
+            text_decoration_line,
+        }
+    }
+
     // This works on an already-constructed `InlineFormattingContext`,
     // Which would have to change if/when
     // `BlockContainer::construct` parallelize their construction.
@@ -256,8 +270,10 @@ impl InlineFormattingContext {
                 inline_start: Length::zero(),
                 max_block_size_of_fragments_so_far: Length::zero(),
                 positioning_context: None,
+                text_decoration_line: self.text_decoration_line,
             },
         };
+
         loop {
             if let Some(child) = ifc.current_nesting_level.remaining_boxes.next() {
                 match &*child.borrow() {
@@ -385,6 +401,7 @@ impl Lines {
             block: line_block_size,
         };
         self.next_line_block_position += size.block;
+
         self.fragments
             .push(Fragment::Anonymous(AnonymousFragment::new(
                 Rect { start_corner, size },
@@ -423,6 +440,8 @@ impl InlineBox {
             start_corner += &relative_adjustement(&style, ifc.containing_block)
         }
         let positioning_context = PositioningContext::new_for_style(&style);
+        let text_decoration_line =
+            ifc.current_nesting_level.text_decoration_line | style.clone_text_decoration_line();
         PartialInlineBoxFragment {
             tag: self.tag,
             style,
@@ -441,6 +460,7 @@ impl InlineBox {
                     inline_start: ifc.inline_position,
                     max_block_size_of_fragments_so_far: Length::zero(),
                     positioning_context,
+                    text_decoration_line: text_decoration_line,
                 },
             ),
         }
@@ -631,8 +651,7 @@ fn layout_atomic(
 }
 
 struct BreakAndShapeResult {
-    font_ascent: Au,
-    font_line_gap: Au,
+    font_metrics: FontMetrics,
     font_key: FontInstanceKey,
     runs: Vec<GlyphRun>,
     break_at_start: bool,
@@ -699,8 +718,7 @@ impl TextRun {
             );
 
             BreakAndShapeResult {
-                font_ascent: font.metrics.ascent,
-                font_line_gap: font.metrics.line_gap,
+                font_metrics: (&font.metrics).into(),
                 font_key: font.font_key,
                 runs,
                 break_at_start,
@@ -712,8 +730,7 @@ impl TextRun {
         use style::values::generics::text::LineHeight;
 
         let BreakAndShapeResult {
-            font_ascent,
-            font_line_gap,
+            font_metrics,
             font_key,
             runs,
             break_at_start: _,
@@ -750,7 +767,7 @@ impl TextRun {
                 }
             }
             let line_height = match self.parent_style.get_inherited_text().line_height {
-                LineHeight::Normal => font_line_gap.into(),
+                LineHeight::Normal => font_metrics.line_gap,
                 LineHeight::Number(n) => font_size * n.0,
                 LineHeight::Length(l) => l.0,
             };
@@ -775,9 +792,10 @@ impl TextRun {
                     debug_id: DebugId::new(),
                     parent_style: self.parent_style.clone(),
                     rect,
-                    ascent: font_ascent.into(),
+                    font_metrics,
                     font_key,
                     glyphs,
+                    text_decoration_line: ifc.current_nesting_level.text_decoration_line,
                 }));
             if runs.is_empty() {
                 break;

components/layout_2020/flow/root.rs

@@ -104,6 +104,7 @@ fn construct_for_root_element<'dom>(
             ))],
         )
     } else {
+        let propagated_text_decoration_line = style.clone_text_decoration_line();
         (
             ContainsFloats::No,
             vec![ArcRefCell::new(BlockLevelBox::Independent(
@@ -114,6 +115,7 @@ fn construct_for_root_element<'dom>(
                     display_inside,
                     contents,
                     ContentSizesRequest::None,
+                    propagated_text_decoration_line,
                 ),
             ))],
         )