1 files changed, 309 insertions, 0 deletions
diff --git a/components/layout/query.rs b/components/layout/query.rs
new file mode 100644
index 00000000000..01f1c6065b5
--- /dev/null
+++ b/components/layout/query.rs
@@ -0,0 +1,309 @@
+/* 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/. */
+
+//! Utilities for querying the layout, as needed by the layout task.
+
+use layout_task::{LayoutTaskData, RWGuard};
+
+use euclid::point::Point2D;
+use euclid::rect::Rect;
+use flow_ref::FlowRef;
+use fragment::{Fragment, FragmentBorderBoxIterator};
+use gfx::display_list::{DisplayItemMetadata, OpaqueNode};
+use msg::constellation_msg::Msg as ConstellationMsg;
+use msg::constellation_msg::ConstellationChan;
+use opaque_node::OpaqueNodeMethods;
+use script::layout_interface::{ContentBoxResponse, ContentBoxesResponse, NodeGeometryResponse};
+use script::layout_interface::{HitTestResponse, LayoutRPC, MouseOverResponse, OffsetParentResponse};
+use script::layout_interface::{ResolvedStyleResponse, ScriptLayoutChan, TrustedNodeAddress};
+use sequential;
+
+use std::sync::{Arc, Mutex};
+use util::geometry::Au;
+use util::cursor::Cursor;
+use util::logical_geometry::WritingMode;
+
+pub struct LayoutRPCImpl(pub Arc<Mutex<LayoutTaskData>>);
+
+impl LayoutRPC for LayoutRPCImpl {
+
+    // The neat thing here is that in order to answer the following two queries we only
+    // need to compare nodes for equality. Thus we can safely work only with `OpaqueNode`.
+    fn content_box(&self) -> ContentBoxResponse {
+        let &LayoutRPCImpl(ref rw_data) = self;
+        let rw_data = rw_data.lock().unwrap();
+        ContentBoxResponse(rw_data.content_box_response)
+    }
+
+    /// Requests the dimensions of all the content boxes, as in the `getClientRects()` call.
+    fn content_boxes(&self) -> ContentBoxesResponse {
+        let &LayoutRPCImpl(ref rw_data) = self;
+        let rw_data = rw_data.lock().unwrap();
+        ContentBoxesResponse(rw_data.content_boxes_response.clone())
+    }
+
+    fn node_geometry(&self) -> NodeGeometryResponse {
+        let &LayoutRPCImpl(ref rw_data) = self;
+        let rw_data = rw_data.lock().unwrap();
+        NodeGeometryResponse {
+            client_rect: rw_data.client_rect_response
+        }
+    }
+
+    /// Retrieves the resolved value for a CSS style property.
+    fn resolved_style(&self) -> ResolvedStyleResponse {
+        let &LayoutRPCImpl(ref rw_data) = self;
+        let rw_data = rw_data.lock().unwrap();
+        ResolvedStyleResponse(rw_data.resolved_style_response.clone())
+    }
+
+    /// Requests the node containing the point of interest.
+    fn hit_test(&self, _: TrustedNodeAddress, point: Point2D<f32>) -> Result<HitTestResponse, ()> {
+        let point = Point2D::new(Au::from_f32_px(point.x), Au::from_f32_px(point.y));
+        let resp = {
+            let &LayoutRPCImpl(ref rw_data) = self;
+            let rw_data = rw_data.lock().unwrap();
+            match rw_data.stacking_context {
+                None => panic!("no root stacking context!"),
+                Some(ref stacking_context) => {
+                    let mut result = Vec::new();
+                    stacking_context.hit_test(point, &mut result, true);
+                    if !result.is_empty() {
+                        Some(HitTestResponse(result[0].node.to_untrusted_node_address()))
+                    } else {
+                        None
+                    }
+                }
+            }
+        };
+
+        if resp.is_some() {
+            return Ok(resp.unwrap());
+        }
+        Err(())
+    }
+
+    fn mouse_over(&self, _: TrustedNodeAddress, point: Point2D<f32>)
+                  -> Result<MouseOverResponse, ()> {
+        let mut mouse_over_list: Vec<DisplayItemMetadata> = vec!();
+        let point = Point2D::new(Au::from_f32_px(point.x), Au::from_f32_px(point.y));
+        {
+            let &LayoutRPCImpl(ref rw_data) = self;
+            let rw_data = rw_data.lock().unwrap();
+            match rw_data.stacking_context {
+                None => panic!("no root stacking context!"),
+                Some(ref stacking_context) => {
+                    stacking_context.hit_test(point, &mut mouse_over_list, false);
+                }
+            }
+
+            // Compute the new cursor.
+            let cursor = if !mouse_over_list.is_empty() {
+                mouse_over_list[0].pointing.unwrap()
+            } else {
+                Cursor::DefaultCursor
+            };
+            let ConstellationChan(ref constellation_chan) = rw_data.constellation_chan;
+            constellation_chan.send(ConstellationMsg::SetCursor(cursor)).unwrap();
+        }
+
+        if mouse_over_list.is_empty() {
+            Err(())
+        } else {
+            let response_list =
+                mouse_over_list.iter()
+                               .map(|metadata| metadata.node.to_untrusted_node_address())
+                               .collect();
+            Ok(MouseOverResponse(response_list))
+        }
+    }
+
+    fn offset_parent(&self) -> OffsetParentResponse {
+        let &LayoutRPCImpl(ref rw_data) = self;
+        let rw_data = rw_data.lock().unwrap();
+        rw_data.offset_parent_response.clone()
+    }
+}
+
+pub struct UnioningFragmentBorderBoxIterator {
+    pub node_address: OpaqueNode,
+    pub rect: Option<Rect<Au>>,
+}
+
+impl UnioningFragmentBorderBoxIterator {
+    pub fn new(node_address: OpaqueNode) -> UnioningFragmentBorderBoxIterator {
+        UnioningFragmentBorderBoxIterator {
+            node_address: node_address,
+            rect: None
+        }
+    }
+}
+
+impl FragmentBorderBoxIterator for UnioningFragmentBorderBoxIterator {
+    fn process(&mut self, _: &Fragment, _: i32, border_box: &Rect<Au>) {
+        self.rect = match self.rect {
+            Some(rect) => {
+                Some(rect.union(border_box))
+            }
+            None => {
+                Some(*border_box)
+            }
+        };
+    }
+
+    fn should_process(&mut self, fragment: &Fragment) -> bool {
+        fragment.contains_node(self.node_address)
+    }
+}
+
+pub struct CollectingFragmentBorderBoxIterator {
+    pub node_address: OpaqueNode,
+    pub rects: Vec<Rect<Au>>,
+}
+
+impl CollectingFragmentBorderBoxIterator {
+    pub fn new(node_address: OpaqueNode) -> CollectingFragmentBorderBoxIterator {
+        CollectingFragmentBorderBoxIterator {
+            node_address: node_address,
+            rects: Vec::new(),
+        }
+    }
+}
+
+impl FragmentBorderBoxIterator for CollectingFragmentBorderBoxIterator {
+    fn process(&mut self, _: &Fragment, _: i32, border_box: &Rect<Au>) {
+        self.rects.push(*border_box);
+    }
+
+    fn should_process(&mut self, fragment: &Fragment) -> bool {
+        fragment.contains_node(self.node_address)
+    }
+}
+
+pub enum Side {
+    Left,
+    Right,
+    Bottom,
+    Top
+}
+
+pub enum MarginPadding {
+    Margin,
+    Padding
+}
+
+pub enum PositionProperty {
+    Left,
+    Right,
+    Top,
+    Bottom,
+    Width,
+    Height,
+}
+
+pub struct PositionRetrievingFragmentBorderBoxIterator {
+    node_address: OpaqueNode,
+    pub result: Option<Au>,
+    position: Point2D<Au>,
+    property: PositionProperty,
+}
+
+impl PositionRetrievingFragmentBorderBoxIterator {
+    pub fn new(node_address: OpaqueNode,
+           property: PositionProperty,
+           position: Point2D<Au>) -> PositionRetrievingFragmentBorderBoxIterator {
+        PositionRetrievingFragmentBorderBoxIterator {
+            node_address: node_address,
+            position: position,
+            property: property,
+            result: None,
+        }
+    }
+}
+
+impl FragmentBorderBoxIterator for PositionRetrievingFragmentBorderBoxIterator {
+    fn process(&mut self, _: &Fragment, _: i32, border_box: &Rect<Au>) {
+        self.result =
+            Some(match self.property {
+                     PositionProperty::Left => self.position.x,
+                     PositionProperty::Top => self.position.y,
+                     PositionProperty::Width => border_box.size.width,
+                     PositionProperty::Height => border_box.size.height,
+                     // TODO: the following 2 calculations are completely wrong.
+                     // They should return the difference between the parent's and this
+                     // fragment's border boxes.
+                     PositionProperty::Right => border_box.max_x() + self.position.x,
+                     PositionProperty::Bottom => border_box.max_y() + self.position.y,
+        });
+    }
+
+    fn should_process(&mut self, fragment: &Fragment) -> bool {
+        fragment.contains_node(self.node_address)
+    }
+}
+
+pub struct MarginRetrievingFragmentBorderBoxIterator {
+    node_address: OpaqueNode,
+    pub result: Option<Au>,
+    writing_mode: WritingMode,
+    margin_padding: MarginPadding,
+    side: Side,
+}
+
+impl MarginRetrievingFragmentBorderBoxIterator {
+    pub fn new(node_address: OpaqueNode, side: Side, margin_padding:
+    MarginPadding, writing_mode: WritingMode) -> MarginRetrievingFragmentBorderBoxIterator {
+        MarginRetrievingFragmentBorderBoxIterator {
+            node_address: node_address,
+            side: side,
+            margin_padding: margin_padding,
+            result: None,
+            writing_mode: writing_mode,
+        }
+    }
+}
+
+impl FragmentBorderBoxIterator for MarginRetrievingFragmentBorderBoxIterator {
+    fn process(&mut self, fragment: &Fragment, _: i32, _: &Rect<Au>) {
+        let rect = match self.margin_padding {
+            MarginPadding::Margin => &fragment.margin,
+            MarginPadding::Padding => &fragment.border_padding
+        };
+        self.result = Some(match self.side {
+                               Side::Left => rect.left(self.writing_mode),
+                               Side::Right => rect.right(self.writing_mode),
+                               Side::Bottom => rect.bottom(self.writing_mode),
+                               Side::Top => rect.top(self.writing_mode)
+        });
+    }
+
+    fn should_process(&mut self, fragment: &Fragment) -> bool {
+        fragment.contains_node(self.node_address)
+    }
+}
+
+pub fn process_content_box_request<'a>(requested_node: TrustedNodeAddress,
+                                       layout_root: &mut FlowRef,
+                                       rw_data: &mut RWGuard<'a>) {
+    // FIXME(pcwalton): This has not been updated to handle the stacking context relative
+    // stuff. So the position is wrong in most cases.
+    let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node);
+    let mut iterator = UnioningFragmentBorderBoxIterator::new(requested_node);
+    sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator);
+    rw_data.content_box_response = match iterator.rect {
+        Some(rect) => rect,
+        None       => Rect::zero()
+    };
+}
+
+pub fn process_content_boxes_request<'a>(requested_node: TrustedNodeAddress,
+                                         layout_root: &mut FlowRef,
+                                         rw_data: &mut RWGuard<'a>) {
+    // FIXME(pcwalton): This has not been updated to handle the stacking context relative
+    // stuff. So the position is wrong in most cases.
+    let requested_node: OpaqueNode = OpaqueNodeMethods::from_script_node(requested_node);
+    let mut iterator = CollectingFragmentBorderBoxIterator::new(requested_node);
+    sequential::iterate_through_flow_tree_fragment_border_boxes(layout_root, &mut iterator);
+    rw_data.content_boxes_response = iterator.rects;
+}