Auto merge of #6662 - tschneidereit:client-geometry, r=glennw,pcwatson

Implement Element.client{Top,Left,Width,Height}

This isn't done, but contains a working implementation of at least `clientTop`. Feedback would be much appreciated: it's probably far from ideal.

Implementing `clientLeft` is straight-forward, I think, but `clientWidth` and `clientHeight` require accessing the `border_box` - and I don't know how that works, yet.

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/6662)
<!-- Reviewable:end -->

components/script/dom/element.rs

@@ -1317,6 +1317,26 @@ impl<'a> ElementMethods for &'a Element {
             rect.origin.x + rect.size.width)
     }
 
+    fn ClientTop(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        node.get_client_rect().origin.y
+    }
+
+    fn ClientLeft(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        node.get_client_rect().origin.x
+    }
+
+    fn ClientWidth(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        node.get_client_rect().size.width
+    }
+
+    fn ClientHeight(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        node.get_client_rect().size.height
+    }
+
     // https://dvcs.w3.org/hg/innerhtml/raw-file/tip/index.html#widl-Element-innerHTML
     fn GetInnerHTML(self) -> Fallible<DOMString> {
         //XXX TODO: XML case

components/script/dom/node.rs

@@ -492,6 +492,7 @@ pub trait NodeHelpers {
 
     fn get_bounding_content_box(self) -> Rect<Au>;
     fn get_content_boxes(self) -> Vec<Rect<Au>>;
+    fn get_client_rect(self) -> Rect<i32>;
 
     fn before(self, nodes: Vec<NodeOrString>) -> ErrorResult;
     fn after(self, nodes: Vec<NodeOrString>) -> ErrorResult;
@@ -794,6 +795,10 @@ impl<'a> NodeHelpers for &'a Node {
         window_from_node(self).r().content_boxes_query(self.to_trusted_node_address())
     }
 
+    fn get_client_rect(self) -> Rect<i32> {
+        window_from_node(self).r().client_rect_query(self.to_trusted_node_address())
+    }
+
     // https://dom.spec.whatwg.org/#dom-childnode-before
     fn before(self, nodes: Vec<NodeOrString>) -> ErrorResult {
         match self.parent_node.get() {

components/script/dom/webidls/Element.webidl

@@ -59,6 +59,11 @@ interface Element : Node {
 partial interface Element {
   DOMRectList getClientRects();
   DOMRect getBoundingClientRect();
+
+  readonly attribute long clientTop;
+  readonly attribute long clientLeft;
+  readonly attribute long clientWidth;
+  readonly attribute long clientHeight;
 };
 
 // https://domparsing.spec.whatwg.org/#extensions-to-the-element-interface

components/script/dom/window.rs

@@ -540,6 +540,7 @@ pub trait WindowHelpers {
     fn layout(&self) -> &LayoutRPC;
     fn content_box_query(self, content_box_request: TrustedNodeAddress) -> Rect<Au>;
     fn content_boxes_query(self, content_boxes_request: TrustedNodeAddress) -> Vec<Rect<Au>>;
+    fn client_rect_query(self, node_geometry_request: TrustedNodeAddress) -> Rect<i32>;
     fn handle_reflow_complete_msg(self, reflow_id: u32);
     fn set_fragment_name(self, fragment: Option<String>);
     fn steal_fragment_name(self) -> Option<String>;
@@ -771,6 +772,13 @@ impl<'a> WindowHelpers for &'a Window {
         rects
     }
 
+    fn client_rect_query(self, node_geometry_request: TrustedNodeAddress) -> Rect<i32> {
+        self.reflow(ReflowGoal::ForScriptQuery,
+                    ReflowQueryType::NodeGeometryQuery(node_geometry_request),
+                    ReflowReason::Query);
+        self.layout_rpc.node_geometry().client_rect
+    }
+
     fn handle_reflow_complete_msg(self, reflow_id: u32) {
         let last_reflow_id = self.last_reflow_id.get();
         if last_reflow_id == reflow_id {
@@ -1077,6 +1085,7 @@ fn debug_reflow_events(goal: &ReflowGoal, query_type: &ReflowQueryType, reason:
         ReflowQueryType::NoQuery => "\tNoQuery",
         ReflowQueryType::ContentBoxQuery(_n) => "\tContentBoxQuery",
         ReflowQueryType::ContentBoxesQuery(_n) => "\tContentBoxesQuery",
+        ReflowQueryType::NodeGeometryQuery(_n) => "\tNodeGeometryQuery",
     });
 
     debug_msg.push_str(match *reason {

components/script/layout_interface.rs

@@ -95,6 +95,8 @@ pub trait LayoutRPC {
     fn content_box(&self) -> ContentBoxResponse;
     /// Requests the dimensions of all the content boxes, as in the `getClientRects()` call.
     fn content_boxes(&self) -> ContentBoxesResponse;
+    /// Requests the geometry of this node. Used by APIs such as `clientTop`.
+    fn node_geometry(&self) -> NodeGeometryResponse;
     /// Requests the node containing the point of interest
     fn hit_test(&self, node: TrustedNodeAddress, point: Point2D<f32>) -> Result<HitTestResponse, ()>;
     fn mouse_over(&self, node: TrustedNodeAddress, point: Point2D<f32>) -> Result<MouseOverResponse, ()>;
@@ -102,6 +104,9 @@ pub trait LayoutRPC {
 
 pub struct ContentBoxResponse(pub Rect<Au>);
 pub struct ContentBoxesResponse(pub Vec<Rect<Au>>);
+pub struct NodeGeometryResponse {
+    pub client_rect: Rect<i32>,
+}
 pub struct HitTestResponse(pub UntrustedNodeAddress);
 pub struct MouseOverResponse(pub Vec<UntrustedNodeAddress>);
 
@@ -120,6 +125,7 @@ pub enum ReflowQueryType {
     NoQuery,
     ContentBoxQuery(TrustedNodeAddress),
     ContentBoxesQuery(TrustedNodeAddress),
+    NodeGeometryQuery(TrustedNodeAddress),
 }
 
 /// Information needed for a reflow.