Implement "handled for descendants" tracking for RestyleDamage.

MozReview-Commit-ID: Bbk99ogILXC
This commit is contained in:
Bobby Holley 2017-02-15 19:36:57 -08:00
parent 1afae52c47
commit d9606a4fae
6 changed files with 135 additions and 23 deletions

View file

@ -245,7 +245,7 @@ static NO_SNAPSHOT: Option<Snapshot> = None;
/// We really want to store an Option<Snapshot> here, but we can't drop Gecko
/// Snapshots off-main-thread. So we make a convenient little wrapper to provide
/// the semantics of Option<Snapshot>, while deferring the actual drop.
#[derive(Debug)]
#[derive(Debug, Default)]
pub struct SnapshotOption {
snapshot: Option<Snapshot>,
destroyed: bool,
@ -292,7 +292,7 @@ impl Deref for SnapshotOption {
/// Transient data used by the restyle algorithm. This structure is instantiated
/// either before or during restyle traversal, and is cleared at the end of node
/// processing.
#[derive(Debug)]
#[derive(Debug, Default)]
pub struct RestyleData {
/// The restyle hint, which indicates whether selectors need to be rematched
/// for this element, its children, and its descendants.
@ -306,22 +306,21 @@ pub struct RestyleData {
/// afte restyling.
pub damage: RestyleDamage,
/// The restyle damage that has already been handled by our ancestors, and does
/// not need to be applied again at this element. Only non-empty during the
/// traversal, once ancestor damage has been calculated.
///
/// Note that this optimization mostly makes sense in terms of Gecko's top-down
/// frame constructor and change list processing model. We don't bother with it
/// for Servo for now.
#[cfg(feature = "gecko")]
pub damage_handled: RestyleDamage,
/// An optional snapshot of the original state and attributes of the element,
/// from which we may compute additional restyle hints at traversal time.
pub snapshot: SnapshotOption,
}
impl Default for RestyleData {
fn default() -> Self {
RestyleData {
hint: StoredRestyleHint::default(),
recascade: false,
damage: RestyleDamage::empty(),
snapshot: SnapshotOption::empty(),
}
}
}
impl RestyleData {
/// Expands the snapshot (if any) into a restyle hint. Returns true if later
/// siblings must be restyled.
@ -354,6 +353,28 @@ impl RestyleData {
self.recascade ||
self.snapshot.is_some()
}
/// Returns damage handled.
#[cfg(feature = "gecko")]
pub fn damage_handled(&self) -> RestyleDamage {
self.damage_handled
}
/// Returns damage handled (always empty for servo).
#[cfg(feature = "servo")]
pub fn damage_handled(&self) -> RestyleDamage {
RestyleDamage::empty()
}
/// Sets damage handled.
#[cfg(feature = "gecko")]
pub fn set_damage_handled(&mut self, d: RestyleDamage) {
self.damage_handled = d;
}
/// Sets damage handled. No-op for Servo.
#[cfg(feature = "servo")]
pub fn set_damage_handled(&mut self, _: RestyleDamage) {}
}
/// Style system data associated with an Element.