Fix a memory leak with Parley fonts

packages/dom/src/layout/construct.rs

@@ -281,11 +281,12 @@ fn collect_complex_layout_children(
 
 fn create_text_editor(doc: &mut Document, input_element_id: usize, is_multiline: bool) {
  let node = &mut doc.nodes[input_element_id];
- let parley_style = node
+ let mut parley_style = node
  .primary_styles()
  .as_ref()
  .map(|s| stylo_to_parley::style(s))
  .unwrap_or_default();
+ let parley_style = parley_style.take_style();
 
  let element = &mut node.raw_dom_data.downcast_element_mut().unwrap();
  if !matches!(element.node_specific_data, NodeSpecificData::TextInput(_)) {
@@ -315,10 +316,11 @@ pub(crate) fn build_inline_layout(
  .and_then(|parent_id| doc.nodes[parent_id].primary_styles())
  });
 
- let parley_style = root_node_style
+ let mut parley_style = root_node_style
  .as_ref()
  .map(|s| stylo_to_parley::style(s))
  .unwrap_or_default();
+ let parley_style = parley_style.take_style();
 
  let root_line_height = parley_style.line_height;
 
@@ -430,6 +432,8 @@ pub(crate) fn build_inline_layout(
  .map(|s| stylo_to_parley::style(&s))
  .unwrap_or_default();
 
+ let mut style = style.take_style();
+
  // Floor the line-height of the span by the line-height of the inline context
  // See https://www.w3.org/TR/CSS21/visudet.html#line-height
  style.line_height = style.line_height.max(root_line_height);

packages/dom/src/stylo_to_parley.rs

@@ -27,7 +27,36 @@ pub(crate) fn white_space_collapse(input: stylo::WhiteSpaceCollapse) -> parley::
  }
 }
 
-pub(crate) fn style(style: &stylo::ComputedValues) -> parley::TextStyle<'static, TextBrush> {
+// TextStyle struct that owns all the data that need a lifetime
+// Should not be constructed externally since it is a self-referencing struct and extra care has to be taken to keep it safe
+#[derive(Default)]
+pub(crate) struct OwnedTextStyle {
+ #[allow(unused)]
+ fonts: Vec<String>,
+ #[allow(unused)]
+ font_stack: Box<[parley::FontFamily<'static>]>,
+ text_style: parley::TextStyle<'static, TextBrush>,
+}
+
+// Not safe as of right now and therefore commented out. Needs to to have a non-static lifetime that is bound to the `self` argument
+/*
+impl Deref for OwnedTextStyle {
+ type Target = parley::TextStyle<'static, TextBrush>;
+
+ fn deref(&self) -> &Self::Target {
+ &self.text_style
+ }
+}
+*/
+
+impl OwnedTextStyle {
+ #[allow(clippy::needless_lifetimes)]
+ pub(crate) fn take_style<'a>(&'a mut self) -> parley::TextStyle<'a, TextBrush> {
+ std::mem::take(&mut self.text_style)
+ }
+}
+
+pub(crate) fn style(style: &stylo::ComputedValues) -> OwnedTextStyle {
  let font_styles = style.get_font();
  // let text_styles = style.get_text();
  let itext_styles = style.get_inherited_text();
@@ -51,7 +80,8 @@ pub(crate) fn style(style: &stylo::ComputedValues) -> parley::TextStyle<'static,
  };
 
  // Convert font family
- let families: Vec<_> = font_styles
+ let mut fonts = Vec::new();
+ let families: Box<[_]> = font_styles
  .font_family
  .families
  .list
@@ -71,8 +101,15 @@ pub(crate) fn style(style: &stylo::ComputedValues) -> parley::TextStyle<'static,
  break 'ret parley::FontFamily::Generic(parley::GenericFamily::SystemUi);
  }
 
- // TODO: fix leak!
- break 'ret parley::FontFamily::Named(name.to_string().leak());
+ let name = name.to_string();
+ fonts.push(name);
+ let name = fonts.last().unwrap() as &str;
+ let name = name as *const str;
+ // this is safe since the string won't be reallocated
+ // and gets deallocated when the self-referencing struct
+ // it's being part of gets dropped
+ let name = unsafe { &*name };
+ break 'ret parley::FontFamily::Named(name);
  }
  }
  stylo::SingleFontFamily::Generic(generic) => {
@@ -89,8 +126,11 @@ pub(crate) fn style(style: &stylo::ComputedValues) -> parley::TextStyle<'static,
  })
  .collect();
 
- // TODO: fix leak!
- let families = Box::leak(families.into_boxed_slice());
+ let families_ptr = &*families as *const [parley::FontFamily<'static>];
+ // this is safe since the array won't be reallocated
+ // and gets deallocated when the self-referencing struct
+ // it's being part of gets dropped
+ let families_ref = unsafe { &*families_ptr };
 
  // Convert text colour
  let color = itext_styles.color.as_peniko();
@@ -102,27 +142,30 @@ pub(crate) fn style(style: &stylo::ComputedValues) -> parley::TextStyle<'static,
  .map(ToPenikoColor::as_peniko)
  .map(|color| TextBrush::Normal(peniko::Brush::Solid(color)));
 
- parley::TextStyle {
- // font_stack: parley::FontStack::Single(FontFamily::Generic(GenericFamily::SystemUi)),
- font_stack: parley::FontStack::List(families),
- font_size,
- font_stretch: Default::default(),
- font_style,
- font_weight,
- font_variations: parley::FontSettings::List(&[]),
- font_features: parley::FontSettings::List(&[]),
- locale: Default::default(),
- brush: TextBrush::Normal(peniko::Brush::Solid(color)),
- has_underline: itext_styles.text_decorations_in_effect.underline,
- underline_offset: Default::default(),
- underline_size: Default::default(),
- underline_brush: decoration_brush.clone(),
- has_strikethrough: itext_styles.text_decorations_in_effect.line_through,
- strikethrough_offset: Default::default(),
- strikethrough_size: Default::default(),
- strikethrough_brush: decoration_brush,
- line_height,
- word_spacing: Default::default(),
- letter_spacing: itext_styles.letter_spacing.0.px(),
+ OwnedTextStyle {
+ fonts,
+ font_stack: families,
+ text_style: parley::TextStyle {
+ font_stack: parley::FontStack::List(families_ref),
+ font_size,
+ font_stretch: Default::default(),
+ font_style,
+ font_weight,
+ font_variations: parley::FontSettings::List(&[]),
+ font_features: parley::FontSettings::List(&[]),
+ locale: Default::default(),
+ brush: TextBrush::Normal(peniko::Brush::Solid(color)),
+ has_underline: itext_styles.text_decorations_in_effect.underline,
+ underline_offset: Default::default(),
+ underline_size: Default::default(),
+ underline_brush: decoration_brush.clone(),
+ has_strikethrough: itext_styles.text_decorations_in_effect.line_through,
+ strikethrough_offset: Default::default(),
+ strikethrough_size: Default::default(),
+ strikethrough_brush: decoration_brush,
+ line_height,
+ word_spacing: Default::default(),
+ letter_spacing: itext_styles.letter_spacing.0.px(),
+ },
  }
 }