Layout 2020 skeleton for display: flex, behind a pref

components/layout_2020/flexbox.rs

@@ -0,0 +1,62 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use crate::context::LayoutContext;
+use crate::dom_traversal::{NodeExt, NonReplacedContents};
+use crate::formatting_contexts::IndependentLayout;
+use crate::positioned::PositioningContext;
+use crate::sizing::{BoxContentSizes, ContentSizesRequest};
+use crate::ContainingBlock;
+use servo_arc::Arc;
+use style::properties::ComputedValues;
+use style::values::specified::text::TextDecorationLine;
+
+// FIXME: `min-width: auto` is not zero: https://drafts.csswg.org/css-flexbox/#min-size-auto
+
+#[derive(Debug, Serialize)]
+pub(crate) struct FlexContainer {
+    unimplemented_fallback: crate::flow::BlockFormattingContext,
+}
+
+impl FlexContainer {
+    pub fn construct<'dom>(
+        context: &LayoutContext,
+        node: impl NodeExt<'dom>,
+        style: &Arc<ComputedValues>,
+        contents: NonReplacedContents,
+        content_sizes: ContentSizesRequest,
+        propagated_text_decoration_line: TextDecorationLine,
+    ) -> (Self, BoxContentSizes) {
+        let (unimplemented_fallback, content_sizes) =
+            crate::flow::BlockFormattingContext::construct(
+                context,
+                node,
+                style,
+                contents,
+                content_sizes,
+                propagated_text_decoration_line,
+            );
+        (
+            Self {
+                unimplemented_fallback,
+            },
+            content_sizes,
+        )
+    }
+
+    pub(crate) fn layout(
+        &self,
+        layout_context: &LayoutContext,
+        positioning_context: &mut PositioningContext,
+        containing_block: &ContainingBlock,
+        tree_rank: usize,
+    ) -> IndependentLayout {
+        self.unimplemented_fallback.layout(
+            layout_context,
+            positioning_context,
+            containing_block,
+            tree_rank,
+        )
+    }
+}

components/layout_2020/formatting_contexts.rs

@@ -4,6 +4,7 @@
 
 use crate::context::LayoutContext;
 use crate::dom_traversal::{Contents, NodeExt};
+use crate::flexbox::FlexContainer;
 use crate::flow::BlockFormattingContext;
 use crate::fragments::Fragment;
 use crate::positioned::PositioningContext;
@@ -43,6 +44,7 @@ pub(crate) struct IndependentLayout {
 #[derive(Debug, Serialize)]
 enum IndependentFormattingContextContents {
     Flow(BlockFormattingContext),
+    Flex(FlexContainer),
 
     // Not called FC in specs, but behaves close enough
     Replaced(ReplacedContent),
@@ -53,6 +55,7 @@ pub(crate) struct NonReplacedIFC<'a>(NonReplacedIFCKind<'a>);
 
 enum NonReplacedIFCKind<'a> {
     Flow(&'a BlockFormattingContext),
+    Flex(&'a FlexContainer),
 }
 
 impl IndependentFormattingContext {
@@ -83,6 +86,22 @@ impl IndependentFormattingContext {
                         contents: IndependentFormattingContextContents::Flow(bfc),
                     }
                 },
+                DisplayInside::Flex => {
+                    let (fc, content_sizes) = FlexContainer::construct(
+                        context,
+                        node,
+                        &style,
+                        non_replaced,
+                        content_sizes,
+                        propagated_text_decoration_line,
+                    );
+                    Self {
+                        tag: node.as_opaque(),
+                        style,
+                        content_sizes,
+                        contents: IndependentFormattingContextContents::Flex(fc),
+                    }
+                },
             },
             Err(replaced) => {
                 let content_sizes = content_sizes.compute(|| replaced.inline_content_sizes(&style));
@@ -103,6 +122,7 @@ impl IndependentFormattingContext {
         match &self.contents {
             Contents::Replaced(r) => Ok(r),
             Contents::Flow(f) => Err(NR(Kind::Flow(f))),
+            Contents::Flex(f) => Err(NR(Kind::Flex(f))),
         }
     }
 }
@@ -122,6 +142,12 @@ impl NonReplacedIFC<'_> {
                 containing_block,
                 tree_rank,
             ),
+            NonReplacedIFCKind::Flex(fc) => fc.layout(
+                layout_context,
+                positioning_context,
+                containing_block,
+                tree_rank,
+            ),
         }
     }
 }

components/layout_2020/lib.rs

@@ -15,6 +15,7 @@ pub mod data;
 pub mod display_list;
 mod dom_traversal;
 pub mod element_data;
+mod flexbox;
 mod flow;
 mod formatting_contexts;
 mod fragments;

components/layout_2020/style_ext.rs

@@ -48,6 +48,7 @@ pub(crate) enum DisplayOutside {
 pub(crate) enum DisplayInside {
     Flow,
     FlowRoot,
+    Flex,
 }
 
 /// Percentages resolved but not `auto` margins
@@ -394,6 +395,7 @@ impl From<stylo::Display> for Display {
         let inside = match packed.inside() {
             stylo::DisplayInside::Flow => DisplayInside::Flow,
             stylo::DisplayInside::FlowRoot => DisplayInside::FlowRoot,
+            stylo::DisplayInside::Flex => DisplayInside::Flex,
 
             // These should not be values of DisplayInside, but oh well
             stylo::DisplayInside::None => return Display::None,