servo: Merge #4190 - Implements the :checked pseudo-class for inputs (from mttr:checked_pseudo_class); r=Manishearth

Relevant spec:
https://html.spec.whatwg.org/multipage/scripting.html#selector-checked

Also modifies HTMLInputElement::SetChecked to no longer modify its
checked content value, instead making use of its internal checkedness
state now that we can match `:checked` properly.

Source-Repo: https://github.com/servo/servo
Source-Revision: f18c18371d2bb5edde9d64e46b74bf01411afab3

servo/components/layout/wrapper.rs

@@ -552,6 +552,13 @@ impl<'le> TElement<'le> for LayoutElement<'le> {
         }
     }
 
+    #[inline]
+    fn get_checked_state(self) -> bool {
+        unsafe {
+            self.element.get_checked_state_for_layout()
+        }
+    }
+
     #[inline]
     fn has_class(self, name: &Atom) -> bool {
         unsafe {

servo/components/script/dom/element.rs

@@ -13,6 +13,7 @@ use dom::bindings::codegen::Bindings::AttrBinding::AttrMethods;
 use dom::bindings::codegen::Bindings::ElementBinding;
 use dom::bindings::codegen::Bindings::ElementBinding::ElementMethods;
 use dom::bindings::codegen::Bindings::EventBinding::EventMethods;
+use dom::bindings::codegen::Bindings::HTMLInputElementBinding::HTMLInputElementMethods;
 use dom::bindings::codegen::Bindings::NamedNodeMapBinding::NamedNodeMapMethods;
 use dom::bindings::codegen::InheritTypes::{ElementDerived, HTMLInputElementDerived, HTMLTableCellElementDerived};
 use dom::bindings::codegen::InheritTypes::{HTMLInputElementCast, NodeCast, EventTargetCast, ElementCast};
@@ -198,6 +199,7 @@ pub trait RawLayoutElementHelpers {
                                               -> LengthOrPercentageOrAuto;
     unsafe fn get_integer_attribute_for_layout(&self, integer_attribute: IntegerAttribute)
                                                -> Option<i32>;
+    unsafe fn get_checked_state_for_layout(&self) -> bool;
     fn local_name<'a>(&'a self) -> &'a Atom;
     fn namespace<'a>(&'a self) -> &'a Namespace;
     fn style_attribute<'a>(&'a self) -> &'a DOMRefCell<Option<style::PropertyDeclarationBlock>>;
@@ -313,6 +315,17 @@ impl RawLayoutElementHelpers for Element {
         }
     }
 
+    #[inline]
+    #[allow(unrooted_must_root)]
+    unsafe fn get_checked_state_for_layout(&self) -> bool {
+        // TODO option and menuitem can also have a checked state.
+        if !self.is_htmlinputelement() {
+            return false
+        }
+        let this: &HTMLInputElement = mem::transmute(self);
+        this.get_checked_state_for_layout()
+    }
+
     // Getters used in components/layout/wrapper.rs
 
     fn local_name<'a>(&'a self) -> &'a Atom {
@@ -1156,6 +1169,12 @@ impl<'a> style::TElement<'a> for JSRef<'a, Element> {
         let node: JSRef<Node> = NodeCast::from_ref(self);
         node.get_enabled_state()
     }
+    fn get_checked_state(self) -> bool {
+        match HTMLInputElementCast::to_ref(self) {
+            Some(input) => input.Checked(),
+            None => false,
+        }
+    }
     fn has_class(self, name: &Atom) -> bool {
         // FIXME(zwarich): Remove this when UFCS lands and there is a better way
         // of disambiguating methods.

servo/components/script/dom/htmlinputelement.rs

@@ -125,6 +125,7 @@ pub trait LayoutHTMLInputElementHelpers {
 }
 
 pub trait RawLayoutHTMLInputElementHelpers {
+    unsafe fn get_checked_state_for_layout(&self) -> bool;
     unsafe fn get_size_for_layout(&self) -> u32;
 }
 
@@ -162,6 +163,11 @@ impl LayoutHTMLInputElementHelpers for JS<HTMLInputElement> {
 }
 
 impl RawLayoutHTMLInputElementHelpers for HTMLInputElement {
+    #[allow(unrooted_must_root)]
+    unsafe fn get_checked_state_for_layout(&self) -> bool {
+        self.checked.get()
+    }
+
     #[allow(unrooted_must_root)]
     unsafe fn get_size_for_layout(&self) -> u32 {
         self.size.get()
@@ -181,7 +187,9 @@ impl<'a> HTMLInputElementMethods for JSRef<'a, HTMLInputElement> {
     }
 
     // https://html.spec.whatwg.org/multipage/forms.html#dom-input-checked
-    make_bool_setter!(SetChecked, "checked")
+    fn SetChecked(self, checked: bool) {
+        self.update_checked_state(checked);
+    }
 
     // https://html.spec.whatwg.org/multipage/forms.html#dom-input-readonly
     make_bool_getter!(ReadOnly)

servo/components/style/node.rs

@@ -45,6 +45,7 @@ pub trait TElement<'a> : Copy {
     fn get_id(self) -> Option<Atom>;
     fn get_disabled_state(self) -> bool;
     fn get_enabled_state(self) -> bool;
+    fn get_checked_state(self) -> bool;
     fn has_class(self, name: &Atom) -> bool;
 
     // Ordinarily I wouldn't use callbacks like this, but the alternative is

servo/components/style/selector_matching.rs

@@ -997,6 +997,12 @@ pub fn matches_simple_selector<'a,E,N>(selector: &SimpleSelector,
             let elem = element.as_element();
             elem.get_enabled_state()
         },
+        // https://html.spec.whatwg.org/multipage/scripting.html#selector-checked
+        Checked => {
+            *shareable = false;
+            let elem = element.as_element();
+            elem.get_checked_state()
+        }
         FirstChild => {
             *shareable = false;
             matches_first_child(element)

servo/components/style/selectors.rs

@@ -68,6 +68,7 @@ pub enum SimpleSelector {
     Hover,
     Disabled,
     Enabled,
+    Checked,
     FirstChild, LastChild, OnlyChild,
 //    Empty,
     Root,
@@ -226,7 +227,7 @@ fn compute_specificity(mut selector: &CompoundSelector,
                 | &AttrExists(..) | &AttrEqual(..) | &AttrIncludes(..) | &AttrDashMatch(..)
                 | &AttrPrefixMatch(..) | &AttrSubstringMatch(..) | &AttrSuffixMatch(..)
                 | &AnyLink | &Link | &Visited | &Hover | &Disabled | &Enabled
-                | &FirstChild | &LastChild | &OnlyChild | &Root
+                | &FirstChild | &LastChild | &OnlyChild | &Root | &Checked
 //                | &Empty | &Lang(*)
                 | &NthChild(..) | &NthLastChild(..)
                 | &NthOfType(..) | &NthLastOfType(..)
@@ -497,6 +498,7 @@ fn parse_simple_pseudo_class(name: &str) -> Result<SimpleSelector, ()> {
         "hover" => Ok(Hover),
         "disabled" => Ok(Disabled),
         "enabled" => Ok(Enabled),
+        "checked" => Ok(Checked),
         "first-child" => Ok(FirstChild),
         "last-child"  => Ok(LastChild),
         "only-child"  => Ok(OnlyChild),

servo/resources/servo.css

@@ -10,9 +10,9 @@ input[type="checkbox"],
 input[type="radio"]     { font-family: monospace !important; border: none !important; background: transparent; }
 
 input[type="checkbox"]::before { content: "[ ]"; padding: 0; }
-input[type="checkbox"][checked]::before { content: "[✓]"; }
+input[type="checkbox"]:checked::before { content: "[✓]"; }
 input[type="radio"]::before { content: "( )"; padding: 0; }
-input[type="radio"][checked]::before { content: "(●)"; }
+input[type="radio"]:checked::before { content: "(●)"; }
 
 td[align="left"]    { text-align: left; }
 td[align="center"]  { text-align: center; }