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Auto merge of #16663 - emilio:style-builder, r=bholley

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style: Add a StyleBuilder struct to avoid refcount and atomic CAS during the cascade.

This should fix most of the complaints that caused
https://bugzilla.mozilla.org/show_bug.cgi?id=1360889 to be open, and also fix a
bunch of other FIXMEs across the style system.

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This commit is contained in:
bors-servo 2017-04-30 18:31:41 -05:00 • committed by GitHub
commit bf0bf4f4b4
11 changed files with 279 additions and 120 deletions
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44
components/style/properties/gecko.mako.rs
View file

@ -102,32 +102,13 @@ pub struct ComputedValues {
}
impl ComputedValues {
/// Inherits style from the parent element, accounting for the default
/// computed values that need to be provided as well.
pub fn inherit_from(parent: &Self, default: &Self) -> Self {
ComputedValues {
custom_properties: parent.custom_properties.clone(),
writing_mode: parent.writing_mode,
root_font_size: parent.root_font_size,
font_size_keyword: parent.font_size_keyword,
cached_system_font: None,
% for style_struct in data.style_structs:
% if style_struct.inherited:
${style_struct.ident}: parent.${style_struct.ident}.clone(),
% else:
${style_struct.ident}: default.${style_struct.ident}.clone(),
% endif
% endfor
}
}
pub fn new(custom_properties: Option<Arc<ComputedValuesMap>>,
writing_mode: WritingMode,
root_font_size: Au,
font_size_keyword: Option<(longhands::font_size::KeywordSize, f32)>,
% for style_struct in data.style_structs:
${style_struct.ident}: Arc<style_structs::${style_struct.name}>,
% endfor
writing_mode: WritingMode,
root_font_size: Au,
font_size_keyword: Option<(longhands::font_size::KeywordSize, f32)>,
% for style_struct in data.style_structs:
${style_struct.ident}: Arc<style_structs::${style_struct.name}>,
% endfor
) -> Self {
ComputedValues {
custom_properties: custom_properties,
@ -168,6 +149,11 @@ impl ComputedValues {
pub fn get_${style_struct.name_lower}(&self) -> &style_structs::${style_struct.name} {
&self.${style_struct.ident}
}
pub fn ${style_struct.name_lower}_arc(&self) -> &Arc<style_structs::${style_struct.name}> {
&self.${style_struct.ident}
}
#[inline]
pub fn mutate_${style_struct.name_lower}(&mut self) -> &mut style_structs::${style_struct.name} {
Arc::make_mut(&mut self.${style_struct.ident})
@ -175,7 +161,7 @@ impl ComputedValues {
% endfor
pub fn custom_properties(&self) -> Option<Arc<ComputedValuesMap>> {
self.custom_properties.as_ref().map(|x| x.clone())
self.custom_properties.clone()
}
#[allow(non_snake_case)]
@ -183,12 +169,6 @@ impl ComputedValues {
!self.get_box().gecko.mBinding.mPtr.mRawPtr.is_null()
}
#[allow(non_snake_case)]
pub fn in_top_layer(&self) -> bool {
matches!(self.get_box().clone__moz_top_layer(),
longhands::_moz_top_layer::SpecifiedValue::top)
}
// FIXME(bholley): Implement this properly.
#[inline]
pub fn is_multicol(&self) -> bool { false }

2
components/style/properties/helpers.mako.rs
View file

@ -478,7 +478,7 @@
SpecifiedValue::Keyword(v) => v,
SpecifiedValue::System(_) => {
% if product == "gecko":
_cx.style.cached_system_font.as_ref().unwrap().${to_rust_ident(name)}
_cx.cached_system_font.as_ref().unwrap().${to_rust_ident(name)}
% else:
unreachable!()
% endif

18
components/style/properties/longhand/font.mako.rs
View file

@ -50,7 +50,7 @@
SpecifiedValue::Value(v) => v,
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
_context.style.cached_system_font.as_ref().unwrap().${name}
_context.cached_system_font.as_ref().unwrap().${name}
</%self:nongecko_unreachable>
}
}
@ -270,7 +270,7 @@
SpecifiedValue::Values(ref v) => computed_value::T(v.clone()),
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
_cx.style.cached_system_font.as_ref().unwrap().font_family.clone()
_cx.cached_system_font.as_ref().unwrap().font_family.clone()
</%self:nongecko_unreachable>
}
}
@ -532,7 +532,7 @@ ${helpers.single_keyword_system("font-variant-caps",
},
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
context.style.cached_system_font.as_ref().unwrap().font_weight.clone()
context.cached_system_font.as_ref().unwrap().font_weight.clone()
</%self:nongecko_unreachable>
}
}
@ -809,7 +809,7 @@ ${helpers.single_keyword_system("font-variant-caps",
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
context.style.cached_system_font.as_ref().unwrap().font_size
context.cached_system_font.as_ref().unwrap().font_size
</%self:nongecko_unreachable>
}
}
@ -982,7 +982,7 @@ ${helpers.single_keyword_system("font-variant-caps",
SpecifiedValue::Number(ref n) => computed_value::T::Number(n.to_computed_value(context)),
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
context.style.cached_system_font.as_ref().unwrap().font_size_adjust
context.cached_system_font.as_ref().unwrap().font_size_adjust
</%self:nongecko_unreachable>
}
}
@ -1966,7 +1966,7 @@ ${helpers.single_keyword_system("font-variant-position",
}
SpecifiedValue::System(_) => {
<%self:nongecko_unreachable>
_context.style.cached_system_font.as_ref().unwrap().font_language_override
_context.cached_system_font.as_ref().unwrap().font_language_override
</%self:nongecko_unreachable>
}
}
@ -2365,11 +2365,11 @@ ${helpers.single_keyword("-moz-math-variant",
/// Must be called before attempting to compute a system font
/// specified value
pub fn resolve_system_font(system: SystemFont, context: &mut Context) {
if context.style.cached_system_font.is_none() {
if context.cached_system_font.is_none() {
let computed = system.to_computed_value(context);
context.style.cached_system_font = Some(computed);
context.cached_system_font = Some(computed);
}
debug_assert!(system == context.style.cached_system_font.as_ref().unwrap().system_font)
debug_assert!(system == context.cached_system_font.as_ref().unwrap().system_font)
}
#[derive(Clone, Debug)]

257
components/style/properties/properties.mako.rs
View file

@ -13,6 +13,7 @@
use std::borrow::Cow;
use std::collections::HashSet;
use std::fmt;
use std::ops::Deref;
use std::sync::Arc;
use app_units::Au;
@ -1725,6 +1726,12 @@ impl ComputedValues {
&self.${style_struct.ident}
}
/// Gets an immutable reference to the refcounted value that wraps
/// `${style_struct.name}`.
pub fn ${style_struct.name_lower}_arc(&self) -> &Arc<style_structs::${style_struct.name}> {
&self.${style_struct.ident}
}
/// Get a mutable reference to the ${style_struct.name} struct.
#[inline]
pub fn mutate_${style_struct.name_lower}(&mut self) -> &mut style_structs::${style_struct.name} {
@ -1737,18 +1744,13 @@ impl ComputedValues {
/// Cloning the Arc here is fine because it only happens in the case where
/// we have custom properties, and those are both rare and expensive.
fn custom_properties(&self) -> Option<Arc<::custom_properties::ComputedValuesMap>> {
self.custom_properties.as_ref().map(|x| x.clone())
self.custom_properties.clone()
}
/// Whether this style has a -moz-binding value. This is always false for
/// Servo for obvious reasons.
pub fn has_moz_binding(&self) -> bool { false }
/// Whether this style has a top-layer style. That's implemented in Gecko
/// via the -moz-top-layer property, but servo doesn't have any concept of a
/// top layer (yet, it's needed for fullscreen).
pub fn in_top_layer(&self) -> bool { false }
/// Returns whether this style's display value is equal to contents.
///
/// Since this isn't supported in Servo, this is always false for Servo.
@ -1967,22 +1969,6 @@ impl ComputedValues {
}
}
impl ComputedValues {
/// Returns whether this computed style represents a floated object.
pub fn floated(&self) -> bool {
self.get_box().clone_float() != longhands::float::computed_value::T::none
}
/// Returns whether this computed style represents an out of flow-positioned
/// object.
pub fn out_of_flow_positioned(&self) -> bool {
use properties::longhands::position::computed_value::T as position;
matches!(self.get_box().clone_position(),
position::absolute | position::fixed)
}
}
/// Return a WritingMode bitflags from the relevant CSS properties.
pub fn get_writing_mode(inheritedbox_style: &style_structs::InheritedBox) -> WritingMode {
use logical_geometry;
@ -2034,6 +2020,176 @@ pub fn get_writing_mode(inheritedbox_style: &style_structs::InheritedBox) -> Wri
flags
}
/// A reference to a style struct of the parent, or our own style struct.
pub enum StyleStructRef<'a, T: 'a> {
/// A borrowed struct from the parent, for example, for inheriting style.
Borrowed(&'a Arc<T>),
/// An owned struct, that we've already mutated.
Owned(T),
}
impl<'a, T: 'a> StyleStructRef<'a, T>
where T: Clone,
{
/// Ensure a mutable reference of this value exists, either cloning the
/// borrowed value, or returning the owned one.
pub fn mutate(&mut self) -> &mut T {
if let StyleStructRef::Borrowed(v) = *self {
*self = StyleStructRef::Owned((**v).clone());
}
match *self {
StyleStructRef::Owned(ref mut v) => v,
StyleStructRef::Borrowed(..) => unreachable!(),
}
}
/// Returns an `Arc` to the internal struct, constructing one if
/// appropriate.
pub fn build(self) -> Arc<T> {
match self {
StyleStructRef::Owned(v) => Arc::new(v),
StyleStructRef::Borrowed(v) => v.clone(),
}
}
}
impl<'a, T: 'a> Deref for StyleStructRef<'a, T> {
type Target = T;
fn deref(&self) -> &T {
match *self {
StyleStructRef::Owned(ref v) => v,
StyleStructRef::Borrowed(v) => &**v,
}
}
}
/// A type used to compute a struct with minimal overhead.
///
/// This allows holding references to the parent/default computed values without
/// actually cloning them, until we either build the style, or mutate the
/// inherited value.
pub struct StyleBuilder<'a> {
custom_properties: Option<Arc<::custom_properties::ComputedValuesMap>>,
/// The writing mode flags.
///
/// TODO(emilio): Make private.
pub writing_mode: WritingMode,
/// The font size of the root element.
pub root_font_size: Au,
/// The keyword behind the current font-size property, if any.
pub font_size_keyword: Option<(longhands::font_size::KeywordSize, f32)>,
% for style_struct in data.active_style_structs():
${style_struct.ident}: StyleStructRef<'a, style_structs::${style_struct.name}>,
% endfor
}
impl<'a> StyleBuilder<'a> {
/// Trivially construct a `StyleBuilder`.
pub fn new(
custom_properties: Option<Arc<::custom_properties::ComputedValuesMap>>,
writing_mode: WritingMode,
root_font_size: Au,
font_size_keyword: Option<(longhands::font_size::KeywordSize, f32)>,
% for style_struct in data.active_style_structs():
${style_struct.ident}: &'a Arc<style_structs::${style_struct.name}>,
% endfor
) -> Self {
StyleBuilder {
custom_properties: custom_properties,
writing_mode: writing_mode,
root_font_size: root_font_size,
font_size_keyword: font_size_keyword,
% for style_struct in data.active_style_structs():
${style_struct.ident}: StyleStructRef::Borrowed(${style_struct.ident}),
% endfor
}
}
/// Creates a StyleBuilder holding only references to the structs of `s`, in
/// order to create a derived style.
pub fn for_derived_style(s: &'a ComputedValues) -> Self {
Self::for_inheritance(s, s)
}
/// Inherits style from the parent element, accounting for the default
/// computed values that need to be provided as well.
pub fn for_inheritance(parent: &'a ComputedValues, default: &'a ComputedValues) -> Self {
Self::new(parent.custom_properties(),
parent.writing_mode,
parent.root_font_size,
parent.font_size_keyword,
% for style_struct in data.active_style_structs():
% if style_struct.inherited:
parent.${style_struct.name_lower}_arc(),
% else:
default.${style_struct.name_lower}_arc(),
% endif
% endfor
)
}
% for style_struct in data.active_style_structs():
/// Gets an immutable view of the current `${style_struct.name}` style.
pub fn get_${style_struct.name_lower}(&self) -> &style_structs::${style_struct.name} {
&self.${style_struct.ident}
}
/// Gets a mutable view of the current `${style_struct.name}` style.
pub fn mutate_${style_struct.name_lower}(&mut self) -> &mut style_structs::${style_struct.name} {
self.${style_struct.ident}.mutate()
}
% endfor
/// Returns whether this computed style represents a floated object.
pub fn floated(&self) -> bool {
self.get_box().clone_float() != longhands::float::computed_value::T::none
}
/// Returns whether this computed style represents an out of flow-positioned
/// object.
pub fn out_of_flow_positioned(&self) -> bool {
use properties::longhands::position::computed_value::T as position;
matches!(self.get_box().clone_position(),
position::absolute | position::fixed)
}
/// Whether this style has a top-layer style. That's implemented in Gecko
/// via the -moz-top-layer property, but servo doesn't have any concept of a
/// top layer (yet, it's needed for fullscreen).
#[cfg(feature = "servo")]
pub fn in_top_layer(&self) -> bool { false }
/// Whether this style has a top-layer style.
#[cfg(feature = "gecko")]
pub fn in_top_layer(&self) -> bool {
matches!(self.get_box().clone__moz_top_layer(),
longhands::_moz_top_layer::computed_value::T::top)
}
/// Turns this `StyleBuilder` into a proper `ComputedValues` instance.
pub fn build(self) -> ComputedValues {
ComputedValues::new(self.custom_properties,
self.writing_mode,
self.root_font_size,
self.font_size_keyword,
% for style_struct in data.active_style_structs():
self.${style_struct.ident}.build(),
% endfor
)
}
/// Get the custom properties map if necessary.
///
/// Cloning the Arc here is fine because it only happens in the case where
/// we have custom properties, and those are both rare and expensive.
fn custom_properties(&self) -> Option<Arc<::custom_properties::ComputedValuesMap>> {
self.custom_properties.clone()
}
}
#[cfg(feature = "servo")]
pub use self::lazy_static_module::INITIAL_SERVO_VALUES;
@ -2202,28 +2358,28 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
::custom_properties::finish_cascade(
custom_properties, &inherited_custom_properties);
let starting_style = if !flags.contains(INHERIT_ALL) {
ComputedValues::new(custom_properties,
WritingMode::empty(),
inherited_style.root_font_size,
inherited_style.font_size_keyword,
% for style_struct in data.active_style_structs():
% if style_struct.inherited:
inherited_style.clone_${style_struct.name_lower}(),
% else:
default_style.clone_${style_struct.name_lower}(),
% endif
% endfor
)
let builder = if !flags.contains(INHERIT_ALL) {
StyleBuilder::new(custom_properties,
WritingMode::empty(),
inherited_style.root_font_size,
inherited_style.font_size_keyword,
% for style_struct in data.active_style_structs():
% if style_struct.inherited:
inherited_style.${style_struct.name_lower}_arc(),
% else:
default_style.${style_struct.name_lower}_arc(),
% endif
% endfor
)
} else {
ComputedValues::new(custom_properties,
WritingMode::empty(),
inherited_style.root_font_size,
inherited_style.font_size_keyword,
% for style_struct in data.active_style_structs():
inherited_style.clone_${style_struct.name_lower}(),
% endfor
)
StyleBuilder::new(custom_properties,
WritingMode::empty(),
inherited_style.root_font_size,
inherited_style.font_size_keyword,
% for style_struct in data.active_style_structs():
inherited_style.${style_struct.name_lower}_arc(),
% endfor
)
};
let mut context = computed::Context {
@ -2231,8 +2387,9 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
device: device,
inherited_style: inherited_style,
layout_parent_style: layout_parent_style,
style: starting_style,
style: builder,
font_metrics_provider: font_metrics_provider,
cached_system_font: None,
in_media_query: false,
quirks_mode: quirks_mode,
};
@ -2382,9 +2539,11 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
let mut style = context.style;
StyleAdjuster::new(&mut style, is_root_element)
.adjust(context.layout_parent_style,
flags.contains(SKIP_ROOT_AND_ITEM_BASED_DISPLAY_FIXUP));
{
StyleAdjuster::new(&mut style, is_root_element)
.adjust(context.layout_parent_style,
flags.contains(SKIP_ROOT_AND_ITEM_BASED_DISPLAY_FIXUP));
}
% if product == "gecko":
// FIXME(emilio): This is effectively creating a new nsStyleBackground
@ -2408,12 +2567,12 @@ pub fn apply_declarations<'a, F, I>(device: &Device,
}
% endif
style
style.build()
}
/// See StyleAdjuster::adjust_for_border_width.
pub fn adjust_border_width(style: &mut ComputedValues) {
pub fn adjust_border_width(style: &mut StyleBuilder) {
% for side in ["top", "right", "bottom", "left"]:
// Like calling to_computed_value, which wouldn't type check.
if style.get_border().clone_border_${side}_style().none_or_hidden() &&