auto merge of #5461 : mbrubeck/servo/focus, r=jdm

Fixes #5460. This supports for simple focusable elements that are their own DOM anchors, like text `input` fields.

Requires servo/rust-selectors#20.  r? @SimonSapin

5 files changed, 71 insertions, 5 deletions

diff --git a/components/script/dom/document.rs b/components/script/dom/document.rs
index 5cb13ac18e9..49eaef294d5 100644
--- a/components/script/dom/document.rs
+++ b/components/script/dom/document.rs
@@ -454,7 +454,20 @@ impl<'a> DocumentHelpers<'a> for JSRef<'a, Document> {
     /// transaction, or none if no elements requested it.
     fn commit_focus_transaction(self) {
         //TODO: dispatch blur, focus, focusout, and focusin events
+
+        if let Some(ref elem) = self.focused.get().root() {
+            let node: JSRef<Node> = NodeCast::from_ref(elem.r());
+            node.set_focus_state(false);
+        }
+
         self.focused.assign(self.possibly_focused.get());
+
+        if let Some(ref elem) = self.focused.get().root() {
+            let node: JSRef<Node> = NodeCast::from_ref(elem.r());
+            node.set_focus_state(true);
+        }
+        // TODO: Update the focus state for all elements in the focus chain.
+        // https://html.spec.whatwg.org/multipage/interaction.html#focus-chain
     }
 
     /// Handles any updates when the document's title has changed.
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index f69392a4126..498432cfd8a 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -1461,6 +1461,13 @@ impl<'a> style::node::TElement<'a> for JSRef<'a, Element> {
         let node: JSRef<Node> = NodeCast::from_ref(self);
         node.get_hover_state()
     }
+    fn get_focus_state(self) -> bool {
+        // TODO: Also check whether the top-level browsing context has the system focus,
+        // and whether this element is a browsing context container.
+        // https://html.spec.whatwg.org/multipage/scripting.html#selector-focus
+        let node: JSRef<Node> = NodeCast::from_ref(self);
+        node.get_focus_state()
+    }
     fn get_id(self) -> Option<Atom> {
         self.get_attribute(ns!(""), &atom!("id")).map(|attr| {
             let attr = attr.root();
diff --git a/components/script/dom/htmlelement.rs b/components/script/dom/htmlelement.rs
index a0d0adaf82b..55c0fc6fcec 100644
--- a/components/script/dom/htmlelement.rs
+++ b/components/script/dom/htmlelement.rs
@@ -10,21 +10,21 @@ use dom::bindings::codegen::Bindings::HTMLElementBinding::HTMLElementMethods;
 use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementMethods;
 use dom::bindings::codegen::Bindings::WindowBinding::WindowMethods;
 use dom::bindings::codegen::InheritTypes::{ElementCast, HTMLFrameSetElementDerived};
-use dom::bindings::codegen::InheritTypes::{EventTargetCast, HTMLInputElementCast};
+use dom::bindings::codegen::InheritTypes::{EventTargetCast, HTMLInputElementCast, NodeCast};
 use dom::bindings::codegen::InheritTypes::{HTMLElementDerived, HTMLBodyElementDerived};
 use dom::bindings::js::{JSRef, Temporary, MutNullableJS};
 use dom::bindings::error::ErrorResult;
 use dom::bindings::error::Error::Syntax;
 use dom::bindings::utils::Reflectable;
 use dom::cssstyledeclaration::{CSSStyleDeclaration, CSSModificationAccess};
-use dom::document::Document;
+use dom::document::{Document, DocumentHelpers};
 use dom::domstringmap::DOMStringMap;
 use dom::element::{Element, ElementTypeId, ActivationElementHelpers, AttributeHandlers};
 use dom::eventtarget::{EventTarget, EventTargetHelpers, EventTargetTypeId};
 use dom::htmlinputelement::HTMLInputElement;
 use dom::htmlmediaelement::HTMLMediaElementTypeId;
 use dom::htmltablecellelement::HTMLTableCellElementTypeId;
-use dom::node::{Node, NodeTypeId, window_from_node};
+use dom::node::{Node, NodeHelpers, NodeTypeId, document_from_node, window_from_node};
 use dom::virtualmethods::VirtualMethods;
 use dom::window::WindowHelpers;
 
@@ -135,6 +135,32 @@ impl<'a> HTMLElementMethods for JSRef<'a, HTMLElement> {
         // https://www.w3.org/Bugs/Public/show_bug.cgi?id=27430 ?
         element.as_maybe_activatable().map(|a| a.synthetic_click_activation(false, false, false, false));
     }
+
+    // https://html.spec.whatwg.org/multipage/interaction.html#dom-focus
+    fn Focus(self) {
+        // TODO: Mark the element as locked for focus and run the focusing steps.
+        // https://html.spec.whatwg.org/multipage/interaction.html#focusing-steps
+        let element: JSRef<Element> = ElementCast::from_ref(self);
+        let document = document_from_node(self).root();
+        let document = document.r();
+        document.begin_focus_transaction();
+        document.request_focus(element);
+        document.commit_focus_transaction();
+    }
+
+    // https://html.spec.whatwg.org/multipage/interaction.html#dom-blur
+    fn Blur(self) {
+        // TODO: Run the unfocusing steps.
+        let node: JSRef<Node> = NodeCast::from_ref(self);
+        if !node.get_focus_state() {
+            return;
+        }
+        // https://html.spec.whatwg.org/multipage/interaction.html#unfocusing-steps
+        let document = document_from_node(self).root();
+        document.r().begin_focus_transaction();
+        // If `request_focus` is not called, focus will be set to None.
+        document.r().commit_focus_transaction();
+    }
 }
 
 // https://html.spec.whatwg.org/#attr-data-*
diff --git a/components/script/dom/node.rs b/components/script/dom/node.rs
index a302308d33a..f9b81cad136 100644
--- a/components/script/dom/node.rs
+++ b/components/script/dom/node.rs
@@ -152,6 +152,8 @@ bitflags! {
         #[doc = "Specifies whether or not there is an authentic click in progress on \
                  this element."]
         const CLICK_IN_PROGRESS = 0x100,
+        #[doc = "Specifies whether this node has the focus."]
+        const IN_FOCUS_STATE = 0x200,
     }
 }
 
@@ -440,6 +442,9 @@ pub trait NodeHelpers<'a> {
     fn get_hover_state(self) -> bool;
     fn set_hover_state(self, state: bool);
 
+    fn get_focus_state(self) -> bool;
+    fn set_focus_state(self, state: bool);
+
     fn get_disabled_state(self) -> bool;
     fn set_disabled_state(self, state: bool);
 
@@ -618,6 +623,14 @@ impl<'a> NodeHelpers<'a> for JSRef<'a, Node> {
         self.set_flag(IN_HOVER_STATE, state)
     }
 
+    fn get_focus_state(self) -> bool {
+        self.get_flag(IN_FOCUS_STATE)
+    }
+
+    fn set_focus_state(self, state: bool) {
+        self.set_flag(IN_FOCUS_STATE, state)
+    }
+
     fn get_disabled_state(self) -> bool {
         self.get_flag(IN_DISABLED_STATE)
     }
@@ -1036,6 +1049,8 @@ pub trait RawLayoutNodeHelpers {
     #[allow(unsafe_code)]
     unsafe fn get_hover_state_for_layout(&self) -> bool;
     #[allow(unsafe_code)]
+    unsafe fn get_focus_state_for_layout(&self) -> bool;
+    #[allow(unsafe_code)]
     unsafe fn get_disabled_state_for_layout(&self) -> bool;
     #[allow(unsafe_code)]
     unsafe fn get_enabled_state_for_layout(&self) -> bool;
@@ -1050,6 +1065,11 @@ impl RawLayoutNodeHelpers for Node {
     }
     #[inline]
     #[allow(unsafe_code)]
+    unsafe fn get_focus_state_for_layout(&self) -> bool {
+        self.flags.get().contains(IN_FOCUS_STATE)
+    }
+    #[inline]
+    #[allow(unsafe_code)]
     unsafe fn get_disabled_state_for_layout(&self) -> bool {
         self.flags.get().contains(IN_DISABLED_STATE)
     }
diff --git a/components/script/dom/webidls/HTMLElement.webidl b/components/script/dom/webidls/HTMLElement.webidl
index 90ef09d7a9f..fa3ecb6bbb2 100644
--- a/components/script/dom/webidls/HTMLElement.webidl
+++ b/components/script/dom/webidls/HTMLElement.webidl
@@ -25,8 +25,8 @@ interface HTMLElement : Element {
            attribute boolean hidden;
   void click();
   //         attribute long tabIndex;
-  //void focus();
-  //void blur();
+  void focus();
+  void blur();
   //         attribute DOMString accessKey;
   //readonly attribute DOMString accessKeyLabel;
   //         attribute boolean draggable;