layout/layout_data.rs -> layout/data.rs

components/layout/data.rs

@@ -0,0 +1,117 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+#![allow(unsafe_blocks)]
+
+use construct::ConstructionResult;
+use incremental::RestyleDamage;
+use parallel::DomParallelInfo;
+use wrapper::{LayoutNode, TLayoutNode};
+
+use script::dom::node::SharedLayoutData;
+use script::layout_interface::LayoutChan;
+use std::mem;
+use std::cell::{Ref, RefMut};
+use style::properties::ComputedValues;
+use std::sync::Arc;
+
+/// Data that layout associates with a node.
+pub struct PrivateLayoutData {
+    /// The results of CSS styling for this node's `before` pseudo-element, if any.
+    pub before_style: Option<Arc<ComputedValues>>,
+
+    /// The results of CSS styling for this node's `after` pseudo-element, if any.
+    pub after_style: Option<Arc<ComputedValues>>,
+
+    /// Description of how to account for recent style changes.
+    pub restyle_damage: RestyleDamage,
+
+    /// The current results of flow construction for this node. This is either a flow or a
+    /// `ConstructionItem`. See comments in `construct.rs` for more details.
+    pub flow_construction_result: ConstructionResult,
+
+    pub before_flow_construction_result: ConstructionResult,
+
+    pub after_flow_construction_result: ConstructionResult,
+
+    /// Information needed during parallel traversals.
+    pub parallel: DomParallelInfo,
+
+    /// Various flags.
+    pub flags: LayoutDataFlags,
+}
+
+impl PrivateLayoutData {
+    /// Creates new layout data.
+    pub fn new() -> PrivateLayoutData {
+        PrivateLayoutData {
+            before_style: None,
+            after_style: None,
+            restyle_damage: RestyleDamage::empty(),
+            flow_construction_result: ConstructionResult::None,
+            before_flow_construction_result: ConstructionResult::None,
+            after_flow_construction_result: ConstructionResult::None,
+            parallel: DomParallelInfo::new(),
+            flags: LayoutDataFlags::empty(),
+        }
+    }
+}
+
+bitflags! {
+    flags LayoutDataFlags: u8 {
+        #[doc="Whether a flow has been newly constructed."]
+        const HAS_NEWLY_CONSTRUCTED_FLOW = 0x01
+    }
+}
+
+pub struct LayoutDataWrapper {
+    pub chan: Option<LayoutChan>,
+    pub shared_data: SharedLayoutData,
+    pub data: Box<PrivateLayoutData>,
+}
+
+impl LayoutDataWrapper {
+    pub fn clear(&self) {
+        // TODO: Clear items related to this node, e.g. compositor layers
+    }
+}
+
+#[allow(dead_code)]
+fn static_assertion(x: Option<LayoutDataWrapper>) {
+    unsafe {
+        let _: Option<::script::dom::node::LayoutData> =
+            ::std::intrinsics::transmute(x);
+    }
+}
+
+/// A trait that allows access to the layout data of a DOM node.
+pub trait LayoutDataAccess {
+    /// Borrows the layout data without checks.
+    unsafe fn borrow_layout_data_unchecked(&self) -> *const Option<LayoutDataWrapper>;
+    /// Borrows the layout data immutably. Fails on a conflicting borrow.
+    fn borrow_layout_data<'a>(&'a self) -> Ref<'a,Option<LayoutDataWrapper>>;
+    /// Borrows the layout data mutably. Fails on a conflicting borrow.
+    fn mutate_layout_data<'a>(&'a self) -> RefMut<'a,Option<LayoutDataWrapper>>;
+}
+
+impl<'ln> LayoutDataAccess for LayoutNode<'ln> {
+    #[inline(always)]
+    unsafe fn borrow_layout_data_unchecked(&self) -> *const Option<LayoutDataWrapper> {
+        mem::transmute(self.get().layout_data_unchecked())
+    }
+
+    #[inline(always)]
+    fn borrow_layout_data<'a>(&'a self) -> Ref<'a,Option<LayoutDataWrapper>> {
+        unsafe {
+            mem::transmute(self.get().layout_data())
+        }
+    }
+
+    #[inline(always)]
+    fn mutate_layout_data<'a>(&'a self) -> RefMut<'a,Option<LayoutDataWrapper>> {
+        unsafe {
+            mem::transmute(self.get().layout_data_mut())
+        }
+    }
+}