Implement offsetParent/Top/Left/Width/Height.

3 files changed, 94 insertions, 3 deletions

diff --git a/components/script/dom/htmlelement.rs b/components/script/dom/htmlelement.rs
index 513a9d39775..376bec890cc 100644
--- a/components/script/dom/htmlelement.rs
+++ b/components/script/dom/htmlelement.rs
@@ -12,7 +12,7 @@ use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementM
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLFrameSetElementDerived};
 use dom::bindings::codegen::InheritTypes::{EventTargetCast, HTMLInputElementCast, NodeCast};
-use dom::bindings::codegen::InheritTypes::{HTMLElementDerived, HTMLBodyElementDerived};
+use dom::bindings::codegen::InheritTypes::{HTMLElementDerived, HTMLBodyElementDerived, HTMLHtmlElementDerived};
 use dom::bindings::js::{JS, MutNullableHeap, Root};
 use dom::bindings::error::ErrorResult;
 use dom::bindings::error::Error::Syntax;
@@ -216,6 +216,63 @@ impl<'a> HTMLElementMethods for &'a HTMLElement {
         // If `request_focus` is not called, focus will be set to None.
         document.r().commit_focus_transaction(FocusType::Element);
     }
+
+    // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
+    fn GetOffsetParent(self) -> Option<Root<Element>> {
+        if self.is_htmlbodyelement() || self.is_htmlhtmlelement() {
+            return None;
+        }
+
+        let node = NodeCast::from_ref(self);
+        let window = window_from_node(self);
+        let (element, _) = window.offset_parent_query(node.to_trusted_node_address());
+
+        element
+    }
+
+    // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
+    fn OffsetTop(self) -> i32 {
+        if self.is_htmlbodyelement() {
+            return 0;
+        }
+
+        let node = NodeCast::from_ref(self);
+        let window = window_from_node(self);
+        let (_, rect) = window.offset_parent_query(node.to_trusted_node_address());
+
+        rect.origin.y.to_nearest_px()
+    }
+
+    // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
+    fn OffsetLeft(self) -> i32 {
+        if self.is_htmlbodyelement() {
+            return 0;
+        }
+
+        let node = NodeCast::from_ref(self);
+        let window = window_from_node(self);
+        let (_, rect) = window.offset_parent_query(node.to_trusted_node_address());
+
+        rect.origin.x.to_nearest_px()
+    }
+
+    // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
+    fn OffsetWidth(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        let window = window_from_node(self);
+        let (_, rect) = window.offset_parent_query(node.to_trusted_node_address());
+
+        rect.size.width.to_nearest_px()
+    }
+
+    // https://drafts.csswg.org/cssom-view/#extensions-to-the-htmlelement-interface
+    fn OffsetHeight(self) -> i32 {
+        let node = NodeCast::from_ref(self);
+        let window = window_from_node(self);
+        let (_, rect) = window.offset_parent_query(node.to_trusted_node_address());
+
+        rect.size.height.to_nearest_px()
+    }
 }
 
 // https://html.spec.whatwg.org/#attr-data-*
diff --git a/components/script/dom/webidls/HTMLElement.webidl b/components/script/dom/webidls/HTMLElement.webidl
index f4c0376b618..90b11d85bff 100644
--- a/components/script/dom/webidls/HTMLElement.webidl
+++ b/components/script/dom/webidls/HTMLElement.webidl
@@ -45,5 +45,16 @@ interface HTMLElement : Element {
   //readonly attribute boolean? commandDisabled;
   //readonly attribute boolean? commandChecked;
 };
+
+// http://dev.w3.org/csswg/cssom-view/#extensions-to-the-htmlelement-interface
+partial interface HTMLElement {
+  // CSSOM things are not [Pure] because they can flush
+  readonly attribute Element? offsetParent;
+  readonly attribute long offsetTop;
+  readonly attribute long offsetLeft;
+  readonly attribute long offsetWidth;
+  readonly attribute long offsetHeight;
+};
+
 HTMLElement implements GlobalEventHandlers;
 HTMLElement implements ElementCSSInlineStyle;
diff --git a/components/script/dom/window.rs b/components/script/dom/window.rs
index d7a9e9f243a..1320ca354b9 100644
--- a/components/script/dom/window.rs
+++ b/components/script/dom/window.rs
@@ -8,7 +8,7 @@ use dom::bindings::codegen::Bindings::EventHandlerBinding::{OnErrorEventHandlerN
 use dom::bindings::codegen::Bindings::DocumentBinding::DocumentMethods;
 use dom::bindings::codegen::Bindings::FunctionBinding::Function;
 use dom::bindings::codegen::Bindings::WindowBinding::{self, WindowMethods, FrameRequestCallback};
-use dom::bindings::codegen::InheritTypes::{NodeCast, EventTargetCast};
+use dom::bindings::codegen::InheritTypes::{NodeCast, ElementCast, EventTargetCast};
 use dom::bindings::global::global_object_for_js_object;
 use dom::bindings::error::{report_pending_exception, Fallible};
 use dom::bindings::error::Error::InvalidCharacter;
@@ -27,7 +27,7 @@ use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 use dom::htmlelement::HTMLElement;
 use dom::location::Location;
 use dom::navigator::Navigator;
-use dom::node::{window_from_node, TrustedNodeAddress, NodeHelpers};
+use dom::node::{window_from_node, TrustedNodeAddress, NodeHelpers, from_untrusted_node_address};
 use dom::performance::Performance;
 use dom::screen::Screen;
 use dom::storage::Storage;
@@ -578,6 +578,7 @@ pub trait WindowHelpers {
     fn client_rect_query(self, node_geometry_request: TrustedNodeAddress) -> Rect<i32>;
     fn resolved_style_query(self, element: TrustedNodeAddress,
                             pseudo: Option<PseudoElement>, property: &Atom) -> Option<String>;
+    fn offset_parent_query(self, node: TrustedNodeAddress) -> (Option<Root<Element>>, Rect<Au>);
     fn handle_reflow_complete_msg(self, reflow_id: u32);
     fn set_fragment_name(self, fragment: Option<String>);
     fn steal_fragment_name(self) -> Option<String>;
@@ -827,6 +828,27 @@ impl<'a> WindowHelpers for &'a Window {
         resolved
     }
 
+    fn offset_parent_query(self, node: TrustedNodeAddress) -> (Option<Root<Element>>, Rect<Au>) {
+        self.reflow(ReflowGoal::ForScriptQuery,
+                    ReflowQueryType::OffsetParentQuery(node),
+                    ReflowReason::Query);
+        let response = self.layout_rpc.offset_parent();
+        let js_runtime = self.js_runtime.borrow();
+        let js_runtime = js_runtime.as_ref().unwrap();
+        let element = match response.node_address {
+            Some(parent_node_address) => {
+                let node = from_untrusted_node_address(js_runtime.rt(),
+                                                       parent_node_address);
+                let element = ElementCast::to_ref(node.r()).unwrap();
+                Some(Root::from_ref(element))
+            }
+            None => {
+                None
+            }
+        };
+        (element, response.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 {
@@ -1135,6 +1157,7 @@ fn debug_reflow_events(goal: &ReflowGoal, query_type: &ReflowQueryType, reason:
         ReflowQueryType::ContentBoxesQuery(_n) => "\tContentBoxesQuery",
         ReflowQueryType::NodeGeometryQuery(_n) => "\tNodeGeometryQuery",
         ReflowQueryType::ResolvedStyleQuery(_, _, _) => "\tResolvedStyleQuery",
+        ReflowQueryType::OffsetParentQuery(_n) => "\tOffsetParentQuery",
     });
 
     debug_msg.push_str(match *reason {