gecko-dev/servo/components/layout/incremental.rs

87 строки
3.5 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::{FlowFlags, Flow, GetBaseFlow};
use style::computed_values::float::T as Float;
use style::selector_parser::RestyleDamage;
use style::servo::restyle_damage::ServoRestyleDamage;
/// Used in a flow traversal to indicate whether this re-layout should be incremental or not.
#[derive(Clone, Copy, PartialEq)]
pub enum RelayoutMode {
Incremental,
Force
}
bitflags! {
pub struct 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 = self.base().flags.contains(FlowFlags::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 = self.mut_base();
// 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 =
kid.base().flags.contains(FlowFlags::IS_ABSOLUTELY_POSITIONED);
kid.mut_base().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(kid.base().restyle_damage.damage_for_parent(
child_is_absolutely_positioned));
has_counter_affecting_children = has_counter_affecting_children ||
kid.base().flags.intersects(FlowFlags::AFFECTS_COUNTERS |
FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN);
}
}
let self_base = self.mut_base();
if self_base.flags.float_kind() != Float::None &&
self_base.restyle_damage.intersects(ServoRestyleDamage::REFLOW) {
special_damage.insert(SpecialRestyleDamage::REFLOW_ENTIRE_DOCUMENT);
}
if has_counter_affecting_children {
self_base.flags.insert(FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN)
} else {
self_base.flags.remove(FlowFlags::HAS_COUNTER_AFFECTING_CHILDREN)
}
special_damage
}
fn reflow_entire_document(self) {
let self_base = self.mut_base();
self_base.restyle_damage.insert(RestyleDamage::rebuild_and_reflow());
self_base.restyle_damage.remove(ServoRestyleDamage::RECONSTRUCT_FLOW);
for kid in self_base.children.iter_mut() {
kid.reflow_entire_document();
}
}
}