Add fragment debug id

components/layout_2020/flow/inline.rs

@@ -7,7 +7,7 @@ use crate::flow::float::FloatBox;
 use crate::flow::FlowLayout;
 use crate::formatting_contexts::IndependentFormattingContext;
 use crate::fragments::CollapsedBlockMargins;
-use crate::fragments::{AnonymousFragment, BoxFragment, Fragment, TextFragment};
+use crate::fragments::{AnonymousFragment, BoxFragment, DebugId, Fragment, TextFragment};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::positioned::{relative_adjustement, AbsolutelyPositionedBox, PositioningContext};
 use crate::sizing::ContentSizes;
@@ -713,6 +713,7 @@ impl TextRun {
                 .fragments_so_far
                 .push(Fragment::Text(TextFragment {
                     tag: self.tag,
+                    debug_id: DebugId::new(),
                     parent_style: self.parent_style.clone(),
                     rect,
                     ascent: font_ascent.into(),

components/layout_2020/flow/mod.rs

@@ -8,8 +8,9 @@ use crate::context::LayoutContext;
 use crate::flow::float::{FloatBox, FloatContext};
 use crate::flow::inline::InlineFormattingContext;
 use crate::formatting_contexts::{IndependentFormattingContext, IndependentLayout, NonReplacedIFC};
-use crate::fragments::{AnonymousFragment, BoxFragment, Fragment};
+use crate::fragments::{AnonymousFragment, BoxFragment};
 use crate::fragments::{CollapsedBlockMargins, CollapsedMargin};
+use crate::fragments::{DebugId, Fragment};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::positioned::{AbsolutelyPositionedBox, PositioningContext};
 use crate::replaced::ReplacedContent;

components/layout_2020/fragments.rs

@@ -4,6 +4,7 @@
 
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::geom::{PhysicalPoint, PhysicalRect};
+use crate::layout_debug;
 use gfx::text::glyph::GlyphStore;
 use gfx_traits::print_tree::PrintTree;
 use serde::ser::{Serialize, SerializeStruct, Serializer};
@@ -27,6 +28,7 @@ pub(crate) enum Fragment {
 
 pub(crate) struct BoxFragment {
     pub tag: OpaqueNode,
+    pub debug_id: DebugId,
     pub style: ServoArc<ComputedValues>,
     pub children: Vec<Fragment>,
 
@@ -61,6 +63,7 @@ pub(crate) struct CollapsedMargin {
 /// Can contain child fragments with relative coordinates, but does not contribute to painting itself.
 #[derive(Serialize)]
 pub(crate) struct AnonymousFragment {
+    pub debug_id: DebugId,
     pub rect: Rect<Length>,
     pub children: Vec<Fragment>,
     pub mode: WritingMode,
@@ -70,6 +73,7 @@ pub(crate) struct AnonymousFragment {
 }
 
 pub(crate) struct TextFragment {
+    pub debug_id: DebugId,
     pub tag: OpaqueNode,
     pub parent_style: ServoArc<ComputedValues>,
     pub rect: Rect<Length>,
@@ -79,6 +83,7 @@ pub(crate) struct TextFragment {
 }
 
 pub(crate) struct ImageFragment {
+    pub debug_id: DebugId,
     pub style: ServoArc<ComputedValues>,
     pub rect: Rect<Length>,
     pub image_key: ImageKey,
@@ -123,6 +128,7 @@ impl Fragment {
 impl AnonymousFragment {
     pub fn no_op(mode: WritingMode) -> Self {
         Self {
+            debug_id: DebugId::new(),
             children: vec![],
             rect: Rect::zero(),
             mode,
@@ -140,6 +146,7 @@ impl AnonymousFragment {
             )
         });
         AnonymousFragment {
+            debug_id: DebugId::new(),
             rect,
             children,
             mode,
@@ -179,6 +186,7 @@ impl BoxFragment {
             });
         BoxFragment {
             tag,
+            debug_id: DebugId::new(),
             style,
             children,
             content_rect,
@@ -349,7 +357,8 @@ impl CollapsedMargin {
 
 impl Serialize for BoxFragment {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        let mut serializer = serializer.serialize_struct("BoxFragment", 6)?;
+        let mut serializer = serializer.serialize_struct("BoxFragment", 7)?;
+        serializer.serialize_field("debug_id", &self.debug_id)?;
         serializer.serialize_field("content_rect", &self.content_rect)?;
         serializer.serialize_field("padding", &self.padding)?;
         serializer.serialize_field("border", &self.border)?;
@@ -365,7 +374,8 @@ impl Serialize for BoxFragment {
 
 impl Serialize for TextFragment {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        let mut serializer = serializer.serialize_struct("TextFragment", 3)?;
+        let mut serializer = serializer.serialize_struct("TextFragment", 4)?;
+        serializer.serialize_field("debug_id", &self.debug_id)?;
         serializer.serialize_field("rect", &self.rect)?;
         serializer.serialize_field("ascent", &self.ascent)?;
         serializer.serialize_field("glyphs", &self.glyphs)?;
@@ -375,8 +385,45 @@ impl Serialize for TextFragment {
 
 impl Serialize for ImageFragment {
     fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
-        let mut serializer = serializer.serialize_struct("ImageFragment", 1)?;
+        let mut serializer = serializer.serialize_struct("ImageFragment", 2)?;
+        serializer.serialize_field("debug_id", &self.debug_id)?;
         serializer.serialize_field("rect", &self.rect)?;
         serializer.end()
     }
 }
+
+#[cfg(not(debug_assertions))]
+#[derive(Clone)]
+pub struct DebugId;
+
+#[cfg(debug_assertions)]
+#[derive(Clone)]
+pub struct DebugId(u16);
+
+#[cfg(not(debug_assertions))]
+impl DebugId {
+    pub fn new() -> DebugId {
+        DebugId
+    }
+}
+
+#[cfg(debug_assertions)]
+impl DebugId {
+    pub fn new() -> DebugId {
+        DebugId(layout_debug::generate_unique_debug_id())
+    }
+}
+
+#[cfg(not(debug_assertions))]
+impl Serialize for DebugId {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        serializer.serialize_str(&format!("{:p}", &self))
+    }
+}
+
+#[cfg(debug_assertions)]
+impl Serialize for DebugId {
+    fn serialize<S: Serializer>(&self, serializer: S) -> Result<S::Ok, S::Error> {
+        serializer.serialize_u16(self.0)
+    }
+}

components/layout_2020/layout_debug.rs

@@ -10,10 +10,15 @@ use serde_json::{to_string, to_value, Value};
 use std::cell::RefCell;
 use std::fs::File;
 use std::io::Write;
+#[cfg(debug_assertions)]
+use std::sync::atomic::{AtomicUsize, Ordering};
 use std::sync::Arc;
 
 thread_local!(static STATE_KEY: RefCell<Option<State>> = RefCell::new(None));
 
+#[cfg(debug_assertions)]
+static DEBUG_ID_COUNTER: AtomicUsize = AtomicUsize::new(0);
+
 pub struct Scope;
 
 #[macro_export]
@@ -80,6 +85,12 @@ impl Drop for Scope {
     }
 }
 
+/// Generate a unique ID for Fragments.
+#[cfg(debug_assertions)]
+pub fn generate_unique_debug_id() -> u16 {
+    DEBUG_ID_COUNTER.fetch_add(1, Ordering::SeqCst) as u16
+}
+
 /// Begin a layout debug trace. If this has not been called,
 /// creating debug scopes has no effect.
 pub fn begin_trace(root: Arc<FragmentTreeRoot>) {

components/layout_2020/positioned.rs

@@ -5,7 +5,7 @@
 use crate::context::LayoutContext;
 use crate::dom_traversal::{Contents, NodeExt};
 use crate::formatting_contexts::IndependentFormattingContext;
-use crate::fragments::{AnonymousFragment, BoxFragment, CollapsedBlockMargins, Fragment};
+use crate::fragments::{AnonymousFragment, BoxFragment, CollapsedBlockMargins, DebugId, Fragment};
 use crate::geom::flow_relative::{Rect, Sides, Vec2};
 use crate::sizing::ContentSizesRequest;
 use crate::style_ext::{ComputedValuesExt, DisplayInside};

components/layout_2020/replaced.rs

@@ -3,7 +3,7 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
 
 use crate::dom_traversal::NodeExt;
-use crate::fragments::{Fragment, ImageFragment};
+use crate::fragments::{DebugId, Fragment, ImageFragment};
 use crate::geom::flow_relative::{Rect, Vec2};
 use crate::geom::PhysicalSize;
 use crate::sizing::ContentSizes;
@@ -113,6 +113,7 @@ impl ReplacedContent {
                 .and_then(|image| image.id)
                 .map(|image_key| {
                     Fragment::Image(ImageFragment {
+                        debug_id: DebugId::new(),
                         style: style.clone(),
                         rect: Rect {
                             start_corner: Vec2::zero(),