Auto merge of #10252 - emilio:selection, r=mbrubeck

Implement ::selection pseudo-element

It only supports `color` and `background`, for now, but it shouldn't be hard to add more properties (like text-shadow).

r? @mbrubeck

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---
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12 files changed, 70 insertions, 23 deletions

diff --git a/components/layout/construct.rs b/components/layout/construct.rs
index 239dc52e01c..d9727e5c8d9 100644
--- a/components/layout/construct.rs
+++ b/components/layout/construct.rs
@@ -217,6 +217,7 @@ impl InlineFragmentsAccumulator {
                 address: node.opaque(),
                 pseudo: node.get_pseudo_element_type().strip(),
                 style: node.style().clone(),
+                selected_style: node.selected_style().clone(),
                 flags: InlineFragmentNodeFlags::empty(),
             }),
             bidi_control_chars: None,
@@ -360,6 +361,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
             let fragment = Fragment::from_opaque_node_and_style(child_node.opaque(),
                                                                 PseudoElementType::Normal,
                                                                 style,
+                                                                child_node.selected_style().clone(),
                                                                 child_node.restyle_damage(),
                                                                 SpecificFragmentInfo::TableRow);
             let mut new_child: FlowRef = Arc::new(TableRowFlow::from_fragment(fragment));
@@ -373,6 +375,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
             let fragment = Fragment::from_opaque_node_and_style(child_node.opaque(),
                                                                 PseudoElementType::Normal,
                                                                 style,
+                                                                child_node.selected_style().clone(),
                                                                 child_node.restyle_damage(),
                                                                 SpecificFragmentInfo::Table);
             let mut new_child: FlowRef = Arc::new(TableFlow::from_fragment(fragment));
@@ -387,6 +390,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 Fragment::from_opaque_node_and_style(child_node.opaque(),
                                                      PseudoElementType::Normal,
                                                      style,
+                                                     child_node.selected_style().clone(),
                                                      child_node.restyle_damage(),
                                                      SpecificFragmentInfo::TableWrapper);
             let mut new_child: FlowRef = Arc::new(TableWrapperFlow::from_fragment(fragment, None));
@@ -584,6 +588,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
                                                                     whitespace_pseudo,
                                                                     whitespace_style,
+                                                                    node.selected_style().clone(),
                                                                     whitespace_damage,
                                                                     fragment_info);
                 inline_fragment_accumulator.fragments.fragments.push_back(fragment);
@@ -713,6 +718,8 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         let mut style = (*style).clone();
         properties::modify_style_for_text(&mut style);
 
+        let selected_style = node.selected_style();
+
         match text_content {
             TextContent::Text(string) => {
                 let info = box UnscannedTextFragmentInfo::new(string, selection);
@@ -720,7 +727,8 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                 fragments.fragments.push_back(Fragment::from_opaque_node_and_style(
                         node.opaque(),
                         node.get_pseudo_element_type().strip(),
-                        style.clone(),
+                        style,
+                        selected_style.clone(),
                         node.restyle_damage(),
                         specific_fragment_info))
             }
@@ -740,6 +748,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                             node.opaque(),
                             node.get_pseudo_element_type().strip(),
                             style.clone(),
+                            selected_style.clone(),
                             node.restyle_damage(),
                             specific_fragment_info))
                 }
@@ -823,6 +832,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                         let kid_node = flow.as_block().fragment.node;
                         let kid_pseudo = flow.as_block().fragment.pseudo.clone();
                         let kid_style = flow.as_block().fragment.style.clone();
+                        let kid_selected_style = flow.as_block().fragment.selected_style.clone();
                         let kid_restyle_damage = flow.as_block().fragment.restyle_damage;
                         let fragment_info = SpecificFragmentInfo::InlineAbsolute(
                             InlineAbsoluteFragmentInfo::new(flow));
@@ -830,6 +840,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                                 kid_node,
                                 kid_pseudo,
                                 kid_style,
+                                kid_selected_style,
                                 kid_restyle_damage,
                                 fragment_info));
                         fragment_accumulator.fragments
@@ -865,6 +876,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
                     let fragment = Fragment::from_opaque_node_and_style(whitespace_node,
                                                                         whitespace_pseudo,
                                                                         whitespace_style,
+                                                                        node.selected_style().clone(),
                                                                         whitespace_damage,
                                                                         fragment_info);
                     fragment_accumulator.fragments.fragments.push_back(fragment)
@@ -962,6 +974,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         let fragment = Fragment::from_opaque_node_and_style(node.opaque(),
                                                             node.get_pseudo_element_type().strip(),
                                                             modified_style.clone(),
+                                                            node.selected_style().clone(),
                                                             node.restyle_damage(),
                                                             fragment_info);
 
@@ -994,6 +1007,7 @@ impl<'a, ConcreteThreadSafeLayoutNode: ThreadSafeLayoutNode>
         let fragment = Fragment::from_opaque_node_and_style(node.opaque(),
                                                             PseudoElementType::Normal,
                                                             style,
+                                                            node.selected_style().clone(),
                                                             node.restyle_damage(),
                                                             fragment_info);
 
@@ -1853,7 +1867,8 @@ fn control_chars_to_fragment(node: &InlineFragmentNodeInfo,
     properties::modify_style_for_text(&mut style);
     Fragment::from_opaque_node_and_style(node.address,
                                          node.pseudo,
-                                         style,
+                                         style.clone(),
+                                         node.selected_style.clone(),
                                          restyle_damage,
                                          info)
 }
diff --git a/components/layout/display_list_builder.rs b/components/layout/display_list_builder.rs
index 7c65db972cf..e6034bb29ab 100644
--- a/components/layout/display_list_builder.rs
+++ b/components/layout/display_list_builder.rs
@@ -104,10 +104,6 @@ impl<'a> DisplayListBuildState<'a> {
 /// The logical width of an insertion point: at the moment, a one-pixel-wide line.
 const INSERTION_POINT_LOGICAL_WIDTH: Au = Au(1 * AU_PER_PX);
 
-// Colors for selected text.  TODO (#8077): Use the ::selection pseudo-element to set these.
-const SELECTION_FOREGROUND_COLOR: RGBA = RGBA { red: 0.0, green: 0.0, blue: 0.0, alpha: 1.0 };
-const SELECTION_BACKGROUND_COLOR: RGBA = RGBA { red: 0.69, green: 0.84, blue: 1.0, alpha: 1.0 };
-
 // TODO(gw): The transforms spec says that perspective length must
 // be positive. However, there is some confusion between the spec
 // and browser implementations as to handling the case of 0 for the
@@ -931,6 +927,8 @@ impl FragmentDisplayListBuilding for Fragment {
         //
         // TODO: Allow non-text fragments to be selected too.
         if scanned_text_fragment_info.selected() {
+            let style = self.selected_style();
+            let background_color = style.resolve_color(style.get_background().background_color);
             state.add_display_item(
                 DisplayItem::SolidColorClass(box SolidColorDisplayItem {
                     base: BaseDisplayItem::new(stacking_relative_border_box,
@@ -938,7 +936,7 @@ impl FragmentDisplayListBuilding for Fragment {
                                                                         &*self.style,
                                                                         Cursor::DefaultCursor),
                                                &clip),
-                    color: SELECTION_BACKGROUND_COLOR.to_gfx_color()
+                    color: background_color.to_gfx_color(),
             }), display_list_section);
         }
 
@@ -1116,11 +1114,14 @@ impl FragmentDisplayListBuilding for Fragment {
                 //
                 // NB: According to CSS-BACKGROUNDS, text shadows render in *reverse* order (front
                 // to back).
+
+                // TODO(emilio): Allow changing more properties by ::selection
                 let text_color = if text_fragment.selected() {
-                    SELECTION_FOREGROUND_COLOR
+                    self.selected_style().get_color().color
                 } else {
                     self.style().get_color().color
                 };
+
                 for text_shadow in self.style.get_effects().text_shadow.0.iter().rev() {
                     let offset = &Point2D::new(text_shadow.offset_x, text_shadow.offset_y);
                     let color = self.style().resolve_color(text_shadow.color);
diff --git a/components/layout/flow.rs b/components/layout/flow.rs
index 41f502d5770..6f603c7a1ac 100644
--- a/components/layout/flow.rs
+++ b/components/layout/flow.rs
@@ -1286,6 +1286,7 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
                     node.opaque(),
                     PseudoElementType::Normal,
                     style,
+                    node.selected_style().clone(),
                     node.restyle_damage(),
                     SpecificFragmentInfo::TableRow);
                 Arc::new(TableRowFlow::from_fragment(fragment))
@@ -1298,6 +1299,7 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
                     node.opaque(),
                     PseudoElementType::Normal,
                     style,
+                    node.selected_style().clone(),
                     node.restyle_damage(),
                     SpecificFragmentInfo::TableCell);
                 let hide = node.style().get_inheritedtable().empty_cells == empty_cells::T::hide;
@@ -1308,6 +1310,7 @@ impl<'a> ImmutableFlowUtils for &'a Flow {
                     Fragment::from_opaque_node_and_style(node.opaque(),
                                                          PseudoElementType::Normal,
                                                          style,
+                                                         node.selected_style().clone(),
                                                          node.restyle_damage(),
                                                          SpecificFragmentInfo::Generic);
                 Arc::new(BlockFlow::from_fragment(fragment, None))
diff --git a/components/layout/fragment.rs b/components/layout/fragment.rs
index f5f1677ad3d..8a6d8bf1c85 100644
--- a/components/layout/fragment.rs
+++ b/components/layout/fragment.rs
@@ -85,6 +85,9 @@ pub struct Fragment {
     /// The CSS style of this fragment.
     pub style: Arc<ServoComputedValues>,
 
+    /// The CSS style of this fragment when it's selected
+    pub selected_style: Arc<ServoComputedValues>,
+
     /// The position of this fragment relative to its owning flow. The size includes padding and
     /// border, but not margin.
     ///
@@ -798,6 +801,7 @@ impl Fragment {
         Fragment {
             node: node.opaque(),
             style: style,
+            selected_style: node.selected_style().clone(),
             restyle_damage: restyle_damage,
             border_box: LogicalRect::zero(writing_mode),
             border_padding: LogicalMargin::zero(writing_mode),
@@ -815,6 +819,7 @@ impl Fragment {
     pub fn from_opaque_node_and_style(node: OpaqueNode,
                                       pseudo: PseudoElementType<()>,
                                       style: Arc<ServoComputedValues>,
+                                      selected_style: Arc<ServoComputedValues>,
                                       mut restyle_damage: RestyleDamage,
                                       specific: SpecificFragmentInfo)
                                       -> Fragment {
@@ -825,6 +830,7 @@ impl Fragment {
         Fragment {
             node: node,
             style: style,
+            selected_style: selected_style,
             restyle_damage: restyle_damage,
             border_box: LogicalRect::zero(writing_mode),
             border_padding: LogicalMargin::zero(writing_mode),
@@ -858,6 +864,7 @@ impl Fragment {
         Fragment {
             node: self.node,
             style: self.style.clone(),
+            selected_style: self.selected_style.clone(),
             restyle_damage: restyle_damage,
             border_box: new_border_box,
             border_padding: self.border_padding,
@@ -1286,6 +1293,11 @@ impl Fragment {
         &*self.style
     }
 
+    #[inline(always)]
+    pub fn selected_style(&self) -> &ServoComputedValues {
+        &*self.selected_style
+    }
+
     pub fn white_space(&self) -> white_space::T {
         self.style().get_inheritedtext().white_space
     }
diff --git a/components/layout/generated_content.rs b/components/layout/generated_content.rs
index d3e9df73f79..7cde02a8781 100644
--- a/components/layout/generated_content.rs
+++ b/components/layout/generated_content.rs
@@ -438,6 +438,7 @@ fn render_text(layout_context: &LayoutContext,
         box UnscannedTextFragmentInfo::new(string, None));
     fragments.push_back(Fragment::from_opaque_node_and_style(node,
                                                              pseudo,
+                                                             style.clone(),
                                                              style,
                                                              RestyleDamage::rebuild_and_reflow(),
                                                              info));
diff --git a/components/layout/inline.rs b/components/layout/inline.rs
index 7cfa976de4b..c0e209d5f78 100644
--- a/components/layout/inline.rs
+++ b/components/layout/inline.rs
@@ -1854,6 +1854,7 @@ impl fmt::Debug for InlineFlow {
 pub struct InlineFragmentNodeInfo {
     pub address: OpaqueNode,
     pub style: Arc<ServoComputedValues>,
+    pub selected_style: Arc<ServoComputedValues>,
     pub pseudo: PseudoElementType<()>,
     pub flags: InlineFragmentNodeFlags,
 }
diff --git a/components/layout/query.rs b/components/layout/query.rs
index a998f1dae13..65296bc1b4e 100644
--- a/components/layout/query.rs
+++ b/components/layout/query.rs
@@ -534,11 +534,12 @@ pub fn process_resolved_style_request<N: LayoutNode>(
             requested_node: N, pseudo: &Option<PseudoElement>,
             property: &Atom, layout_root: &mut FlowRef) -> Option<String> {
     let layout_node = requested_node.to_threadsafe();
-    let layout_node = match pseudo {
-        &Some(PseudoElement::Before) => layout_node.get_before_pseudo(),
-        &Some(PseudoElement::After) => layout_node.get_after_pseudo(),
-        &Some(PseudoElement::DetailsSummary) => layout_node.get_details_summary_pseudo(),
-        &Some(PseudoElement::DetailsContent) => layout_node.get_details_content_pseudo(),
+    let layout_node = match *pseudo {
+        Some(PseudoElement::Before) => layout_node.get_before_pseudo(),
+        Some(PseudoElement::After) => layout_node.get_after_pseudo(),
+        Some(PseudoElement::DetailsSummary) => layout_node.get_details_summary_pseudo(),
+        Some(PseudoElement::DetailsContent) => layout_node.get_details_content_pseudo(),
+        Some(PseudoElement::Selection) => None,
         _ => Some(layout_node)
     };
 
diff --git a/components/layout/text.rs b/components/layout/text.rs
index 50b36e05e8b..30ce9f4bb41 100644
--- a/components/layout/text.rs
+++ b/components/layout/text.rs
@@ -368,6 +368,7 @@ impl TextRunScanner {
                 let new_fragment = old_fragment.transform(
                     bounding_box_size,
                     SpecificFragmentInfo::ScannedText(new_text_fragment_info));
+
                 out_fragments.push(new_fragment)
             }
         }
diff --git a/components/layout/wrapper.rs b/components/layout/wrapper.rs
index 387e5238d07..a0f7c54de93 100644
--- a/components/layout/wrapper.rs
+++ b/components/layout/wrapper.rs
@@ -702,11 +702,14 @@ pub trait ThreadSafeLayoutNode : Clone + Copy + Sized + PartialEq {
             })
     }
 
+    // TODO(emilio): Since the ::-details-* pseudos are internal, just affecting one element, and
+    // only changing `display` property when the element `open` attribute changes, this should be
+    // eligible for not being cascaded eagerly, reading the display property from layout instead.
     #[inline]
     fn get_details_summary_pseudo(&self) -> Option<Self> {
         if self.is_element() &&
-                self.as_element().get_local_name() == &atom!("details") &&
-                self.as_element().get_namespace() == &ns!(html) {
+           self.as_element().get_local_name() == &atom!("details") &&
+           self.as_element().get_namespace() == &ns!(html) {
             self.borrow_layout_data().unwrap()
                 .style_data.per_pseudo
                 .get(&PseudoElement::DetailsSummary)
@@ -721,8 +724,8 @@ pub trait ThreadSafeLayoutNode : Clone + Copy + Sized + PartialEq {
     #[inline]
     fn get_details_content_pseudo(&self) -> Option<Self> {
         if self.is_element() &&
-                self.as_element().get_local_name() == &atom!("details") &&
-                self.as_element().get_namespace() == &ns!(html) {
+           self.as_element().get_local_name() == &atom!("details") &&
+           self.as_element().get_namespace() == &ns!(html) {
             self.borrow_layout_data().unwrap()
                 .style_data.per_pseudo
                 .get(&PseudoElement::DetailsContent)
@@ -764,6 +767,13 @@ pub trait ThreadSafeLayoutNode : Clone + Copy + Sized + PartialEq {
         })
     }
 
+    #[inline]
+    fn selected_style(&self) -> Ref<Arc<ServoComputedValues>> {
+        Ref::map(self.borrow_layout_data().unwrap(), |data| {
+            data.style_data.per_pseudo.get(&PseudoElement::Selection).unwrap_or(data.style_data.style.as_ref().unwrap())
+        })
+    }
+
     /// Removes the style from this node.
     ///
     /// Unlike the version on TNode, this handles pseudo-elements.
@@ -1015,7 +1025,7 @@ impl<'ln> ThreadSafeLayoutNode for ServoThreadSafeLayoutNode<'ln> {
     }
 
     fn text_content(&self) -> TextContent {
-        if self.pseudo != PseudoElementType::Normal {
+        if self.pseudo.is_before_or_after() {
             let data = &self.borrow_layout_data().unwrap().style_data;
 
             let style = if self.pseudo.is_before() {
@@ -1136,7 +1146,6 @@ impl<ConcreteNode> Iterator for ThreadSafeLayoutNodeChildrenIterator<ConcreteNod
     type Item = ConcreteNode;
     fn next(&mut self) -> Option<ConcreteNode> {
         match self.parent_node.get_pseudo_element_type() {
-
             PseudoElementType::Before(_) | PseudoElementType::After(_) => None,
 
             PseudoElementType::DetailsSummary(_) => {
@@ -1162,8 +1171,8 @@ impl<ConcreteNode> Iterator for ThreadSafeLayoutNodeChildrenIterator<ConcreteNod
                 let node = self.current_node.clone();
                 let node = node.and_then(|node| {
                     if node.is_element() &&
-                            node.as_element().get_local_name() == &atom!("summary") &&
-                            node.as_element().get_namespace() == &ns!(html) {
+                       node.as_element().get_local_name() == &atom!("summary") &&
+                       node.as_element().get_namespace() == &ns!(html) {
                         unsafe { node.dangerous_next_sibling() }
                     } else {
                         Some(node)
diff --git a/components/style/selector_impl.rs b/components/style/selector_impl.rs
index 7fcdab1cc6b..7d6c7efc267 100644
--- a/components/style/selector_impl.rs
+++ b/components/style/selector_impl.rs
@@ -26,6 +26,7 @@ pub trait SelectorImplExt : SelectorImpl + Sized {
 pub enum PseudoElement {
     Before,
     After,
+    Selection,
     DetailsSummary,
     DetailsContent,
 }
@@ -105,6 +106,7 @@ impl SelectorImpl for ServoSelectorImpl {
         let pseudo_element = match_ignore_ascii_case! { name,
             "before" => Before,
             "after" => After,
+            "selection" => Selection,
             "-servo-details-summary" => if context.in_user_agent_stylesheet {
                 DetailsSummary
             } else {
@@ -136,6 +138,7 @@ impl SelectorImplExt for ServoSelectorImpl {
         fun(PseudoElement::After);
         fun(PseudoElement::DetailsContent);
         fun(PseudoElement::DetailsSummary);
+        fun(PseudoElement::Selection);
     }
 
     #[inline]
diff --git a/tests/unit/layout/size_of.rs b/tests/unit/layout/size_of.rs
index 4c47cee0bd8..f79e352cdc9 100644
--- a/tests/unit/layout/size_of.rs
+++ b/tests/unit/layout/size_of.rs
@@ -7,7 +7,7 @@ use std::mem::size_of;
 
 #[test]
 fn test_size_of_fragment() {
-    let expected = 160;
+    let expected = 168;
     let actual = size_of::<Fragment>();
 
     if actual < expected {
diff --git a/tests/unit/util/lib.rs b/tests/unit/util/lib.rs
index b3157b85ca0..a844057a4b0 100644
--- a/tests/unit/util/lib.rs
+++ b/tests/unit/util/lib.rs
@@ -2,7 +2,7 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-#![cfg_attr(test, feature(plugin, custom_derive, heap_api))]
+#![cfg_attr(test, feature(plugin, custom_derive))]
 #![cfg_attr(test, plugin(plugins))]
 #![feature(alloc)]