servo/components/layout/incremental.rs

79 lines
3.3 KiB
Rust

/* 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 http://mozilla.org/MPL/2.0/. */
use flow::{self, AFFECTS_COUNTERS, Flow, HAS_COUNTER_AFFECTING_CHILDREN, IS_ABSOLUTELY_POSITIONED};
use script_layout_interface::restyle_damage::{RestyleDamage, REFLOW, RECONSTRUCT_FLOW};
use style::computed_values::float;
use style::dom::TRestyleDamage;
bitflags! {
pub flags SpecialRestyleDamage: u8 {
#[doc = "If this flag is set, we need to reflow the entire document. This is more or less a \
temporary hack to deal with cases that we don't handle incrementally yet."]
const REFLOW_ENTIRE_DOCUMENT = 0x01,
}
}
pub trait LayoutDamageComputation {
fn compute_layout_damage(self) -> SpecialRestyleDamage;
fn reflow_entire_document(self);
}
impl<'a> LayoutDamageComputation for &'a mut Flow {
fn compute_layout_damage(self) -> SpecialRestyleDamage {
let mut special_damage = SpecialRestyleDamage::empty();
let is_absolutely_positioned = flow::base(self).flags.contains(IS_ABSOLUTELY_POSITIONED);
// In addition to damage, we use this phase to compute whether nodes affect CSS counters.
let mut has_counter_affecting_children = false;
{
let self_base = flow::mut_base(self);
// Take a snapshot of the parent damage before updating it with damage from children.
let parent_damage = self_base.restyle_damage;
for kid in self_base.children.iter_mut() {
let child_is_absolutely_positioned =
flow::base(kid).flags.contains(IS_ABSOLUTELY_POSITIONED);
flow::mut_base(kid).restyle_damage.insert(
parent_damage.damage_for_child(is_absolutely_positioned,
child_is_absolutely_positioned));
{
let kid: &mut Flow = kid;
special_damage.insert(kid.compute_layout_damage());
}
self_base.restyle_damage
.insert(flow::base(kid).restyle_damage.damage_for_parent(
child_is_absolutely_positioned));
has_counter_affecting_children = has_counter_affecting_children ||
flow::base(kid).flags.intersects(AFFECTS_COUNTERS |
HAS_COUNTER_AFFECTING_CHILDREN);
}
}
let self_base = flow::mut_base(self);
if self_base.flags.float_kind() != float::T::none &&
self_base.restyle_damage.intersects(REFLOW) {
special_damage.insert(REFLOW_ENTIRE_DOCUMENT);
}
if has_counter_affecting_children {
self_base.flags.insert(HAS_COUNTER_AFFECTING_CHILDREN)
} else {
self_base.flags.remove(HAS_COUNTER_AFFECTING_CHILDREN)
}
special_damage
}
fn reflow_entire_document(self) {
let self_base = flow::mut_base(self);
self_base.restyle_damage.insert(RestyleDamage::rebuild_and_reflow());
self_base.restyle_damage.remove(RECONSTRUCT_FLOW);
for kid in self_base.children.iter_mut() {
kid.reflow_entire_document();
}
}
}