gecko-dev/servo/components/style/traversal_flags.rs
2018-12-03 08:43:48 -05:00

77 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 https://mozilla.org/MPL/2.0/. */
//! Flags that control the traversal process.
//!
//! We CamelCase rather than UPPER_CASING so that we can grep for the same
//! strings across gecko and servo.
#![allow(non_upper_case_globals)]
bitflags! {
/// Flags that control the traversal process.
pub struct TraversalFlags: u32 {
/// Traverse only elements for animation restyles.
const AnimationOnly = 1 << 0;
/// Traverse and update all elements with CSS animations since
/// @keyframes rules may have changed. Triggered by CSS rule changes.
const ForCSSRuleChanges = 1 << 1;
/// A forgetful traversal ignores the previous state of the frame tree, and
/// thus does not compute damage or maintain other state describing the styles
/// pre-traversal. A forgetful traversal is usually the right thing if you
/// aren't going to do a post-traversal.
const Forgetful = 1 << 3;
/// Clears all the dirty bits on the elements traversed.
const ClearDirtyBits = 1 << 5;
/// Clears the animation-only dirty descendants bit in the subtree.
const ClearAnimationOnlyDirtyDescendants = 1 << 6;
/// Allows the traversal to run in parallel if there are sufficient cores on
/// the machine.
const ParallelTraversal = 1 << 7;
/// Flush throttled animations. By default, we only update throttled animations
/// when we have other non-throttled work to do. With this flag, we
/// unconditionally tick and process them.
const FlushThrottledAnimations = 1 << 8;
}
}
/// Asserts that all TraversalFlags flags have a matching ServoTraversalFlags value in gecko.
#[cfg(feature = "gecko")]
#[inline]
pub fn assert_traversal_flags_match() {
use crate::gecko_bindings::structs;
macro_rules! check_traversal_flags {
( $( $a:ident => $b:path ),*, ) => {
if cfg!(debug_assertions) {
let mut modes = TraversalFlags::all();
$(
assert_eq!(structs::$a as usize, $b.bits() as usize, stringify!($b));
modes.remove($b);
)*
assert_eq!(modes, TraversalFlags::empty(), "all TraversalFlags bits should have an assertion");
}
}
}
check_traversal_flags! {
ServoTraversalFlags_AnimationOnly => TraversalFlags::AnimationOnly,
ServoTraversalFlags_ForCSSRuleChanges => TraversalFlags::ForCSSRuleChanges,
ServoTraversalFlags_Forgetful => TraversalFlags::Forgetful,
ServoTraversalFlags_ClearDirtyBits => TraversalFlags::ClearDirtyBits,
ServoTraversalFlags_ClearAnimationOnlyDirtyDescendants =>
TraversalFlags::ClearAnimationOnlyDirtyDescendants,
ServoTraversalFlags_ParallelTraversal => TraversalFlags::ParallelTraversal,
ServoTraversalFlags_FlushThrottledAnimations => TraversalFlags::FlushThrottledAnimations,
}
}
impl TraversalFlags {
/// Returns true if the traversal is for animation-only restyles.
#[inline]
pub fn for_animation_only(&self) -> bool {
self.contains(TraversalFlags::AnimationOnly)
}
}