Auto merge of #6019 - Ms2ger:preshint-border, r=pcwalton

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/6019)
<!-- Reviewable:end -->

components/script/dom/attr.rs

@@ -306,6 +306,7 @@ impl<'a> AttrHelpers<'a> for JSRef<'a, Attr> {
 
 #[allow(unsafe_code)]
 pub trait AttrHelpersForLayout {
+    unsafe fn value_forever(&self) -> &'static AttrValue;
     unsafe fn value_ref_forever(&self) -> &'static str;
     unsafe fn value_atom_forever(&self) -> Option<Atom>;
     unsafe fn value_tokens_forever(&self) -> Option<&'static [Atom]>;
@@ -314,6 +315,12 @@ pub trait AttrHelpersForLayout {
 
 #[allow(unsafe_code)]
 impl AttrHelpersForLayout for Attr {
+    #[inline]
+    unsafe fn value_forever(&self) -> &'static AttrValue {
+        // This transmute is used to cheat the lifetime restriction.
+        mem::transmute::<&AttrValue, &AttrValue>(self.value.borrow_for_layout())
+    }
+
     #[inline]
     unsafe fn value_ref_forever(&self) -> &'static str {
         // This transmute is used to cheat the lifetime restriction.

components/script/dom/element.rs

@@ -156,6 +156,8 @@ impl Element {
 
 #[allow(unsafe_code)]
 pub trait RawLayoutElementHelpers {
+    unsafe fn get_attr_for_layout<'a>(&'a self, namespace: &Namespace, name: &Atom)
+                                      -> Option<&'a AttrValue>;
     unsafe fn get_attr_val_for_layout<'a>(&'a self, namespace: &Namespace, name: &Atom)
                                       -> Option<&'a str>;
     unsafe fn get_attr_vals_for_layout<'a>(&'a self, name: &Atom) -> Vec<&'a str>;
@@ -190,6 +192,13 @@ unsafe fn get_attr_for_layout(elem: &Element, namespace: &Namespace, name: &Atom
 #[allow(unsafe_code)]
 impl RawLayoutElementHelpers for Element {
     #[inline]
+    unsafe fn get_attr_for_layout<'a>(&'a self, namespace: &Namespace, name: &Atom)
+                                      -> Option<&'a AttrValue> {
+        get_attr_for_layout(self, namespace, name).map(|attr| {
+            (*attr.unsafe_get()).value_forever()
+        })
+    }
+
     unsafe fn get_attr_val_for_layout<'a>(&'a self, namespace: &Namespace, name: &Atom)
                                           -> Option<&'a str> {
         get_attr_for_layout(self, namespace, name).map(|attr| {
@@ -374,6 +383,30 @@ impl RawLayoutElementHelpers for Element {
                     longhands::height::SpecifiedValue(
                         specified::LengthOrPercentageOrAuto::Length(value))))));
         }
+
+
+        let border = if self.is_htmltableelement() {
+            let this: &HTMLTableElement = mem::transmute(self);
+            this.get_border()
+        } else {
+            None
+        };
+
+        if let Some(border) = border {
+            let width_value = specified::Length::Absolute(Au::from_px(border as i32));
+            hints.push(from_declaration(
+                PropertyDeclaration::BorderTopWidth(SpecifiedValue(
+                    longhands::border_top_width::SpecifiedValue(width_value)))));
+            hints.push(from_declaration(
+                PropertyDeclaration::BorderLeftWidth(SpecifiedValue(
+                    longhands::border_left_width::SpecifiedValue(width_value)))));
+            hints.push(from_declaration(
+                PropertyDeclaration::BorderBottomWidth(SpecifiedValue(
+                    longhands::border_bottom_width::SpecifiedValue(width_value)))));
+            hints.push(from_declaration(
+                PropertyDeclaration::BorderRightWidth(SpecifiedValue(
+                    longhands::border_right_width::SpecifiedValue(width_value)))));
+        }
     }
 
     #[inline]
@@ -403,16 +436,6 @@ impl RawLayoutElementHelpers for Element {
                                                         attribute: UnsignedIntegerAttribute)
                                                         -> Option<u32> {
         match attribute {
-            UnsignedIntegerAttribute::Border => {
-                if self.is_htmltableelement() {
-                    let this: &HTMLTableElement = mem::transmute(self);
-                    this.get_border()
-                } else {
-                    // Don't panic since `:-servo-nonzero-border` can cause this to be called on
-                    // arbitrary elements.
-                    None
-                }
-            }
             UnsignedIntegerAttribute::ColSpan => {
                 if self.is_htmltablecellelement() {
                     let this: &HTMLTableCellElement = mem::transmute(self);

components/script/dom/htmltableelement.rs

@@ -2,7 +2,7 @@
  * 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/. */
 
-use dom::attr::{Attr, AttrHelpers};
+use dom::attr::{Attr, AttrHelpers, AttrValue};
 use dom::bindings::codegen::Bindings::HTMLTableElementBinding::HTMLTableElementMethods;
 use dom::bindings::codegen::Bindings::HTMLTableElementBinding;
 use dom::bindings::codegen::Bindings::NodeBinding::NodeMethods;
@@ -17,8 +17,11 @@ use dom::htmltablecaptionelement::HTMLTableCaptionElement;
 use dom::node::{Node, NodeHelpers, NodeTypeId};
 use dom::virtualmethods::VirtualMethods;
 
-use cssparser::RGBA;
 use util::str::{self, DOMString, LengthOrPercentageOrAuto};
+
+use cssparser::RGBA;
+use string_cache::Atom;
+
 use std::cell::Cell;
 
 #[dom_struct]
@@ -158,5 +161,12 @@ impl<'a> VirtualMethods for JSRef<'a, HTMLTableElement> {
             _ => ()
         }
     }
+
+    fn parse_plain_attribute(&self, local_name: &Atom, value: DOMString) -> AttrValue {
+        match local_name {
+            &atom!("border") => AttrValue::from_u32(value, 1),
+            _ => self.super_type().unwrap().parse_plain_attribute(local_name, value),
+        }
+    }
 }