/* 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
https://mozilla.org/MPL/2.0/. */
//! The restyle damage is a hint that tells layout which kind of operations may
//! be needed in presence of incremental style changes.
use crate::computed_values::display::T as Display;
use crate::matching::{StyleChange, StyleDifference};
use crate::properties::ComputedValues;
use std::fmt;
bitflags! {
/// Individual layout actions that may be necessary after restyling.
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub struct ServoRestyleDamage: u8 {
/// Repaint the node itself.
///
/// Currently unused; need to decide how this propagates.
const REPAINT = 0x01;
/// The stacking-context-relative position of this node or its
/// descendants has changed.
///
/// Propagates both up and down the flow tree.
const REPOSITION = 0x02;
/// Recompute the overflow regions (bounding box of object and all descendants).
///
/// Propagates down the flow tree because the computation is bottom-up.
const STORE_OVERFLOW = 0x04;
/// Recompute intrinsic inline_sizes (minimum and preferred).
///
/// Propagates down the flow tree because the computation is.
/// bottom-up.
const BUBBLE_ISIZES = 0x08;
/// Recompute actual inline-sizes and block-sizes, only taking
/// out-of-flow children into account.
///
/// Propagates up the flow tree because the computation is top-down.
const REFLOW_OUT_OF_FLOW = 0x10;
/// Recompute actual inline_sizes and block_sizes.
///
/// Propagates up the flow tree because the computation is top-down.
const REFLOW = 0x20;
/// Re-resolve generated content.
///
/// Propagates up the flow tree because the computation is inorder.
const RESOLVE_GENERATED_CONTENT = 0x40;
/// The entire flow needs to be reconstructed.
const RECONSTRUCT_FLOW = 0x80;
}
}
malloc_size_of_is_0!(ServoRestyleDamage);
impl ServoRestyleDamage {
/// Compute the `StyleDifference` (including the appropriate restyle damage)
/// for a given style change between `old` and `new`.
pub fn compute_style_difference(old: &ComputedValues, new: &ComputedValues) -> StyleDifference {
let damage = compute_damage(old, new);
let change = if damage.is_empty() {
StyleChange::Unchanged
} else {
// FIXME(emilio): Differentiate between reset and inherited
// properties here, and set `reset_only` appropriately so the
// optimization to skip the cascade in those cases applies.
StyleChange::Changed { reset_only: false }
};
StyleDifference { damage, change }
}
/// Returns a bitmask that represents a flow that needs to be rebuilt and
/// reflowed.
///
/// FIXME(bholley): Do we ever actually need this? Shouldn't
/// RECONSTRUCT_FLOW imply everything else?
pub fn rebuild_and_reflow() -> ServoRestyleDamage {
ServoRestyleDamage::REPAINT |
ServoRestyleDamage::REPOSITION |
ServoRestyleDamage::STORE_OVERFLOW |
ServoRestyleDamage::BUBBLE_ISIZES |
ServoRestyleDamage::REFLOW_OUT_OF_FLOW |
ServoRestyleDamage::REFLOW |
ServoRestyleDamage::RECONSTRUCT_FLOW
}
/// Returns a bitmask indicating that the frame needs to be reconstructed.
pub fn reconstruct() -> ServoRestyleDamage {
ServoRestyleDamage::RECONSTRUCT_FLOW
}
/// Supposing a flow has the given `position` property and this damage,
/// returns the damage that we should add to the *parent* of this flow.
pub fn damage_for_parent(self, child_is_absolutely_positioned: bool) -> ServoRestyleDam
age {
if child_is_absolutely_positioned {
self & (ServoRestyleDamage::REPAINT |
ServoRestyleDamage::REPOSITION |
ServoRestyleDamage::STORE_OVERFLOW |
ServoRestyleDamage::REFLOW_OUT_OF_FLOW |
ServoRestyleDamage::RESOLVE_GENERATED_CONTENT)
} else {
self & (ServoRestyleDamage::REPAINT |
ServoRestyleDamage::REPOSITION |
ServoRestyleDamage::STORE_OVERFLOW |
ServoRestyleDamage::REFLOW |
ServoRestyleDamage::REFLOW_OUT_OF_FLOW |
ServoRestyleDamage::RESOLVE_GENERATED_CONTENT)
}
}
/// Supposing the *parent* of a flow with the given `position` property has
/// this damage, returns the damage that we should add to this flow.
pub fn damage_for_child(
self,
parent_is_absolutely_positioned: bool,
child_is_absolutely_positioned: bool,
) -> ServoRestyleDamage {
match (
parent_is_absolutely_positioned,
child_is_absolutely_positioned,
) {
(false, true) => {
// Absolute children are out-of-flow and therefore insulated from changes.
//
// FIXME(pcwalton): Au contraire, if the containing block dimensions change!
self & (ServoRestyleDamage::REPAINT | ServoRestyleDamage::REPOSITION)
},
(true, false) => {
// Changing the position of an absolutely-positioned block requires us to reflow
// its kids.
if self.contains(ServoRestyleDamage::REFLOW_OUT_OF_FLOW) {
self | ServoRestyleDamage::REFLOW
} else {
self
}
},
_ => {
// TODO(pcwalton): Take floatedness into account.
self & (ServoRestyleDamage::REPAINT |
ServoRestyleDamage::REPOSITION |
ServoRestyleDamage::REFLOW)
},
}
}
}
impl Default for ServoRestyleDamage {
fn default() -> Self {
Self::empty()
}
}
impl fmt::Display for ServoRestyleDamage {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
let mut first_elem = true;
let to_iter = [
(ServoRestyleDamage::REPAINT, "Repaint"),
(ServoRestyleDamage::REPOSITION, "Reposition"),
(ServoRestyleDamage::STORE_OVERFLOW, "StoreOverflow"),
(ServoRestyleDamage::BUBBLE_ISIZES, "BubbleISizes"),
(ServoRestyleDamage::REFLOW_OUT_OF_FLOW, "ReflowOutOfFlow"),
(ServoRestyleDamage::REFLOW, "Reflow"),
(
ServoRestyleDamage::RESOLVE_GENERATED_CONTENT,
"ResolveGeneratedContent",
),
(ServoRestyleDamage::RECONSTRUCT_FLOW, "ReconstructFlow"),
];
for &(damage, damage_str) in &to_iter {
if self.contains(damage) {
if !first_elem {
write!(f, " | ")?;
}
write!(f, "{}", damage_str)?;
first_elem = false;
}
}
if first_elem {
write!(f, "NoDamage")?;
}
Ok(())
}
}
fn compute_damage(old: &ComputedValues, new: &ComputedValues) -> ServoRestyleDamage {
let mut damage = ServoRestyleDamage::empty();
// This should check every CSS property, as enumerated in the fields of
// https://doc.servo.org/style/properties/struct.ComputedValues.html
// This uses short-circuiting boolean OR for its side effects and ignores the result.
let _ = restyle_damage_rebuild_and_reflow!(
old,
new,
damage,
[
ServoRestyleDamage::REPAINT,
ServoRestyleDamage::REPOSITION,
ServoRestyleDamage::STORE_OVERFLOW,
ServoRestyleDamage::BUBBLE_ISIZES,
ServoRestyleDamage::REFLOW_OUT_OF_FLOW,
ServoRestyleDamage::REFLOW,
ServoRestyleDamage::RECONSTRUCT_FLOW
],
old.get_box().original_display != new.get_box().original_display
) || (new.get_box().display == Display::Inline &&
restyle_damage_rebuild_and_reflow_inline!(
old,
new,
damage,
[
ServoRestyleDamage::REPAINT,
ServoRestyleDamage::REPOSITION,
ServoRestyleDamage::STORE_OVERFLOW,
ServoRestyleDamage::BUBBLE_ISIZES,
ServoRestyleDamage::REFLOW_OUT_OF_FLOW,
ServoRestyleDamage::REFLOW,
ServoRestyleDamage::RECONSTRUCT_FLOW
]
)) ||
restyle_damage_reflow!(
old,
new,
damage,
[
ServoRestyleDamage::REPAINT,
ServoRestyleDamage::REPOSITION,
ServoRestyleDamage::STORE_OVERFLOW,
ServoRestyleDamage::BUBBLE_ISIZES,
ServoRestyleDamage::REFLOW_OUT_OF_FLOW,
ServoRestyleDamage::REFLOW
]
) ||
restyle_damage_reflow_out_of_flow!(
old,
new,
damage,
[
ServoRestyleDamage::REPAINT,
ServoRestyleDamage::REPOSITION,
ServoRestyleDamage::STORE_OVERFLOW,
ServoRestyleDamage::REFLOW_OUT_OF_FLOW
]
) ||
restyle_damage_repaint!(old, new, damage, [ServoRestyleDamage::REPAINT]);
// Paint worklets may depend on custom properties,
// so if they have changed we should repaint.
if !old.custom_properties_equal(new) {
damage.insert(ServoRestyleDamage::REPAINT);
}
// If the layer requirements of this flow have changed due to the value
// of the transform, then reflow is required to rebuild the layers.
if old.transform_requires_layer() != new.transform_requires_layer() {
damage.insert(ServoRestyleDamage::rebuild_and_reflow());
}
damage
}
