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-rw-r--r--servo/components/style/gecko/snapshot.rs238
1 files changed, 238 insertions, 0 deletions
diff --git a/servo/components/style/gecko/snapshot.rs b/servo/components/style/gecko/snapshot.rs
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+++ b/servo/components/style/gecko/snapshot.rs
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+/* 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/. */
+
+//! A gecko snapshot, that stores the element attributes and state before they
+//! change in order to properly calculate restyle hints.
+
+use crate::dom::TElement;
+use crate::gecko::snapshot_helpers;
+use crate::gecko::wrapper::{GeckoElement, NamespaceConstraintHelpers};
+use crate::gecko_bindings::bindings;
+use crate::gecko_bindings::structs::ServoElementSnapshot;
+use crate::gecko_bindings::structs::ServoElementSnapshotFlags as Flags;
+use crate::gecko_bindings::structs::ServoElementSnapshotTable;
+use crate::invalidation::element::element_wrapper::ElementSnapshot;
+use crate::selector_parser::AttrValue;
+use crate::string_cache::{Atom, Namespace};
+use crate::values::{AtomIdent, AtomString};
+use crate::LocalName;
+use crate::WeakAtom;
+use dom::ElementState;
+use selectors::attr::{AttrSelectorOperation, AttrSelectorOperator};
+use selectors::attr::{CaseSensitivity, NamespaceConstraint};
+
+/// A snapshot of a Gecko element.
+pub type GeckoElementSnapshot = ServoElementSnapshot;
+
+/// A map from elements to snapshots for Gecko's style back-end.
+pub type SnapshotMap = ServoElementSnapshotTable;
+
+impl SnapshotMap {
+ /// Gets the snapshot for this element, if any.
+ ///
+ /// FIXME(emilio): The transmute() business we do here is kind of nasty, but
+ /// it's a consequence of the map being a OpaqueNode -> Snapshot table in
+ /// Servo and an Element -> Snapshot table in Gecko.
+ ///
+ /// We should be able to make this a more type-safe with type annotations by
+ /// making SnapshotMap a trait and moving the implementations outside, but
+ /// that's a pain because it implies parameterizing SharedStyleContext.
+ pub fn get<E: TElement>(&self, element: &E) -> Option<&GeckoElementSnapshot> {
+ debug_assert!(element.has_snapshot());
+
+ unsafe {
+ let element = ::std::mem::transmute::<&E, &GeckoElement>(element);
+ bindings::Gecko_GetElementSnapshot(self, element.0).as_ref()
+ }
+ }
+}
+
+impl GeckoElementSnapshot {
+ #[inline]
+ fn has_any(&self, flags: Flags) -> bool {
+ (self.mContains as u8 & flags as u8) != 0
+ }
+
+ /// Returns true if the snapshot has stored state for pseudo-classes
+ /// that depend on things other than `ElementState`.
+ #[inline]
+ pub fn has_other_pseudo_class_state(&self) -> bool {
+ self.has_any(Flags::OtherPseudoClassState)
+ }
+
+ /// Returns true if the snapshot recorded an id change.
+ #[inline]
+ pub fn id_changed(&self) -> bool {
+ self.mIdAttributeChanged()
+ }
+
+ /// Returns true if the snapshot recorded a class attribute change.
+ #[inline]
+ pub fn class_changed(&self) -> bool {
+ self.mClassAttributeChanged()
+ }
+
+ /// Executes the callback once for each attribute that changed.
+ #[inline]
+ pub fn each_attr_changed<F>(&self, mut callback: F)
+ where
+ F: FnMut(&AtomIdent),
+ {
+ for attr in self.mChangedAttrNames.iter() {
+ unsafe { AtomIdent::with(attr.mRawPtr, &mut callback) }
+ }
+ }
+
+ /// selectors::Element::attr_matches
+ pub fn attr_matches(
+ &self,
+ ns: &NamespaceConstraint<&Namespace>,
+ local_name: &LocalName,
+ operation: &AttrSelectorOperation<&AttrValue>,
+ ) -> bool {
+ unsafe {
+ match *operation {
+ AttrSelectorOperation::Exists => {
+ bindings::Gecko_SnapshotHasAttr(self, ns.atom_or_null(), local_name.as_ptr())
+ },
+ AttrSelectorOperation::WithValue {
+ operator,
+ case_sensitivity,
+ expected_value,
+ } => {
+ let ignore_case = match case_sensitivity {
+ CaseSensitivity::CaseSensitive => false,
+ CaseSensitivity::AsciiCaseInsensitive => true,
+ };
+ // FIXME: case sensitivity for operators other than Equal
+ match operator {
+ AttrSelectorOperator::Equal => bindings::Gecko_SnapshotAttrEquals(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ ),
+ AttrSelectorOperator::Includes => bindings::Gecko_SnapshotAttrIncludes(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ ),
+ AttrSelectorOperator::DashMatch => bindings::Gecko_SnapshotAttrDashEquals(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ ),
+ AttrSelectorOperator::Prefix => bindings::Gecko_SnapshotAttrHasPrefix(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ ),
+ AttrSelectorOperator::Suffix => bindings::Gecko_SnapshotAttrHasSuffix(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ ),
+ AttrSelectorOperator::Substring => {
+ bindings::Gecko_SnapshotAttrHasSubstring(
+ self,
+ ns.atom_or_null(),
+ local_name.as_ptr(),
+ expected_value.as_ptr(),
+ ignore_case,
+ )
+ },
+ }
+ },
+ }
+ }
+ }
+}
+
+impl ElementSnapshot for GeckoElementSnapshot {
+ fn debug_list_attributes(&self) -> String {
+ use nsstring::nsCString;
+ let mut string = nsCString::new();
+ unsafe {
+ bindings::Gecko_Snapshot_DebugListAttributes(self, &mut string);
+ }
+ String::from_utf8_lossy(&*string).into_owned()
+ }
+
+ fn state(&self) -> Option<ElementState> {
+ if self.has_any(Flags::State) {
+ Some(ElementState::from_bits_retain(self.mState))
+ } else {
+ None
+ }
+ }
+
+ #[inline]
+ fn has_attrs(&self) -> bool {
+ self.has_any(Flags::Attributes)
+ }
+
+ #[inline]
+ fn id_attr(&self) -> Option<&WeakAtom> {
+ if !self.has_any(Flags::Id) {
+ return None;
+ }
+
+ snapshot_helpers::get_id(&*self.mAttrs)
+ }
+
+ #[inline]
+ fn is_part(&self, name: &AtomIdent) -> bool {
+ let attr = match snapshot_helpers::find_attr(&*self.mAttrs, &atom!("part")) {
+ Some(attr) => attr,
+ None => return false,
+ };
+
+ snapshot_helpers::has_class_or_part(name, CaseSensitivity::CaseSensitive, attr)
+ }
+
+ #[inline]
+ fn imported_part(&self, name: &AtomIdent) -> Option<AtomIdent> {
+ snapshot_helpers::imported_part(&*self.mAttrs, name)
+ }
+
+ #[inline]
+ fn has_class(&self, name: &AtomIdent, case_sensitivity: CaseSensitivity) -> bool {
+ if !self.has_any(Flags::MaybeClass) {
+ return false;
+ }
+
+ snapshot_helpers::has_class_or_part(name, case_sensitivity, &self.mClass)
+ }
+
+ #[inline]
+ fn each_class<F>(&self, callback: F)
+ where
+ F: FnMut(&AtomIdent),
+ {
+ if !self.has_any(Flags::MaybeClass) {
+ return;
+ }
+
+ snapshot_helpers::each_class_or_part(&self.mClass, callback)
+ }
+
+ #[inline]
+ fn lang_attr(&self) -> Option<AtomString> {
+ let ptr = unsafe { bindings::Gecko_SnapshotLangValue(self) };
+ if ptr.is_null() {
+ None
+ } else {
+ Some(AtomString(unsafe { Atom::from_addrefed(ptr) }))
+ }
+ }
+}