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Update WebRender

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This allows servo to use the ExternalScrollId API from WebRender fixing
some issues related to duplicate scroll root ids.

Fixes #17176.
Fixes #19287.
Fixes #19648.
This commit is contained in:
Martin Robinson 2018-01-16 18:47:05 +01:00
parent 984f3ccc41
commit 99eb457fc7
19 changed files with 154 additions and 119 deletions
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27
components/gfx_traits/lib.rs
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@ -56,10 +56,10 @@ int_range_index! {
struct ByteIndex(isize)
}
/// The type of fragment that a stacking context represents.
/// The type of fragment that a scroll root is created for.
///
/// This can only ever grow to maximum 4 entries. That's because we cram the value of this enum
/// into the lower 2 bits of the `StackingContextId`, which otherwise contains a 32-bit-aligned
/// into the lower 2 bits of the `ScrollRootId`, which otherwise contains a 32-bit-aligned
/// heap address.
#[derive(Clone, Copy, Debug, Deserialize, Eq, Hash, MallocSizeOf, PartialEq, Serialize)]
pub enum FragmentType {
@ -71,23 +71,20 @@ pub enum FragmentType {
AfterPseudoContent,
}
/// The next ID that will be used for a special stacking context.
/// The next ID that will be used for a special scroll root id.
///
/// A special stacking context is a stacking context that is one of (a) the outer stacking context
/// of an element with `overflow: scroll`; (b) generated content; (c) both (a) and (b).
static NEXT_SPECIAL_STACKING_CONTEXT_ID: AtomicUsize = ATOMIC_USIZE_INIT;
/// A special scroll root is a scroll root that is created for generated content.
static NEXT_SPECIAL_SCROLL_ROOT_ID: AtomicUsize = ATOMIC_USIZE_INIT;
/// If none of the bits outside this mask are set, the stacking context is a special stacking
/// context.
///
/// If none of the bits outside this mask are set, the scroll root is a special scroll root.
/// Note that we assume that the top 16 bits of the address space are unused on the platform.
const SPECIAL_STACKING_CONTEXT_ID_MASK: usize = 0xffff;
const SPECIAL_SCROLL_ROOT_ID_MASK: usize = 0xffff;
/// Returns a new stacking context ID for a special stacking context.
/// Returns a new scroll root ID for a scroll root.
fn next_special_id() -> usize {
// We shift this left by 2 to make room for the fragment type ID.
((NEXT_SPECIAL_STACKING_CONTEXT_ID.fetch_add(1, Ordering::SeqCst) + 1) << 2) &
SPECIAL_STACKING_CONTEXT_ID_MASK
((NEXT_SPECIAL_SCROLL_ROOT_ID.fetch_add(1, Ordering::SeqCst) + 1) << 2) &
SPECIAL_SCROLL_ROOT_ID_MASK
}
pub fn combine_id_with_fragment_type(id: usize, fragment_type: FragmentType) -> usize {
@ -99,8 +96,8 @@ pub fn combine_id_with_fragment_type(id: usize, fragment_type: FragmentType) ->
}
}
pub fn node_id_from_clip_id(id: usize) -> Option<usize> {
if (id & !SPECIAL_STACKING_CONTEXT_ID_MASK) != 0 {
pub fn node_id_from_scroll_id(id: usize) -> Option<usize> {
if (id & !SPECIAL_SCROLL_ROOT_ID_MASK) != 0 {
return Some((id & !3) as usize);
}
None