Auto merge of #5988 - Ms2ger:preshints, r=pcwalton

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/5988)
<!-- Reviewable:end -->

4 files changed, 116 insertions, 199 deletions

diff --git a/components/layout/wrapper.rs b/components/layout/wrapper.rs
index 33e343df99f..f9a214daf20 100644
--- a/components/layout/wrapper.rs
+++ b/components/layout/wrapper.rs
@@ -60,7 +60,7 @@ use script::dom::node::{HAS_CHANGED, IS_DIRTY, HAS_DIRTY_SIBLINGS, HAS_DIRTY_DES
 use script::dom::text::Text;
 use script::layout_interface::LayoutChan;
 use msg::constellation_msg::{PipelineId, SubpageId};
-use util::str::{LengthOrPercentageOrAuto, is_whitespace};
+use util::str::is_whitespace;
 use std::borrow::ToOwned;
 use std::cell::{Ref, RefMut};
 use std::marker::PhantomData;
@@ -71,8 +71,7 @@ use style::computed_values::content::ContentItem;
 use style::computed_values::{content, display, white_space};
 use selectors::matching::DeclarationBlock;
 use selectors::parser::{NamespaceConstraint, AttrSelector};
-use style::legacy::{IntegerAttribute, LengthAttribute};
-use style::legacy::{UnsignedIntegerAttribute};
+use style::legacy::UnsignedIntegerAttribute;
 use style::node::{TElement, TElementAttributes, TNode};
 use style::properties::{PropertyDeclaration, PropertyDeclarationBlock};
 use util::smallvec::VecLike;
@@ -657,18 +656,6 @@ impl<'le> TElementAttributes<'le> for LayoutElement<'le> {
         }
     }
 
-    fn get_length_attribute(self, length_attribute: LengthAttribute) -> LengthOrPercentageOrAuto {
-        unsafe {
-            self.element.get_length_attribute_for_layout(length_attribute)
-        }
-    }
-
-    fn get_integer_attribute(self, integer_attribute: IntegerAttribute) -> Option<i32> {
-        unsafe {
-            self.element.get_integer_attribute_for_layout(integer_attribute)
-        }
-    }
-
     fn get_unsigned_integer_attribute(self, attribute: UnsignedIntegerAttribute) -> Option<u32> {
         unsafe {
             self.element.get_unsigned_integer_attribute_for_layout(attribute)
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index 4989039802d..18481db2c2d 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -59,10 +59,13 @@ use dom::virtualmethods::{VirtualMethods, vtable_for};
 
 use devtools_traits::AttrInfo;
 use style;
-use style::legacy::{UnsignedIntegerAttribute, IntegerAttribute, LengthAttribute, from_declaration};
+use style::legacy::{UnsignedIntegerAttribute, from_declaration};
 use style::properties::{PropertyDeclarationBlock, PropertyDeclaration, parse_style_attribute};
 use style::properties::DeclaredValue::SpecifiedValue;
-use style::values::specified::CSSColor;
+use style::properties::longhands::{self, border_spacing};
+use style::values::CSSFloat;
+use style::values::specified::{self, CSSColor};
+use util::geometry::Au;
 use util::namespace;
 use util::smallvec::VecLike;
 use util::str::{DOMString, LengthOrPercentageOrAuto};
@@ -162,10 +165,6 @@ pub trait RawLayoutElementHelpers {
 
     unsafe fn synthesize_presentational_hints_for_legacy_attributes<V>(&self, &mut V)
         where V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
-    unsafe fn get_length_attribute_for_layout(&self, length_attribute: LengthAttribute)
-                                              -> LengthOrPercentageOrAuto;
-    unsafe fn get_integer_attribute_for_layout(&self, integer_attribute: IntegerAttribute)
-                                               -> Option<i32>;
     unsafe fn get_checked_state_for_layout(&self) -> bool;
     unsafe fn get_indeterminate_state_for_layout(&self) -> bool;
     unsafe fn get_unsigned_integer_attribute_for_layout(&self, attribute: UnsignedIntegerAttribute)
@@ -260,51 +259,120 @@ impl RawLayoutElementHelpers for Element {
                 PropertyDeclaration::BackgroundColor(SpecifiedValue(
                     CSSColor { parsed: Color::RGBA(color), authored: None }))));
         }
-    }
 
-    #[inline]
-    unsafe fn get_length_attribute_for_layout(&self, length_attribute: LengthAttribute)
-                                              -> LengthOrPercentageOrAuto {
-        match length_attribute {
-            LengthAttribute::Width => {
-                if self.is_htmltableelement() {
-                    let this: &HTMLTableElement = mem::transmute(self);
-                    this.get_width()
-                } else if self.is_htmltablecellelement() {
-                    let this: &HTMLTableCellElement = mem::transmute(self);
-                    this.get_width()
-                } else {
-                    panic!("I'm not a table or table cell!")
+
+        let cellspacing = if self.is_htmltableelement() {
+            let this: &HTMLTableElement = mem::transmute(self);
+            this.get_cellspacing()
+        } else {
+            None
+        };
+
+        if let Some(cellspacing) = cellspacing {
+            let width_value = specified::Length::Absolute(Au::from_px(cellspacing as i32));
+            hints.push(from_declaration(
+                PropertyDeclaration::BorderSpacing(SpecifiedValue(
+                    border_spacing::SpecifiedValue {
+                        horizontal: width_value,
+                        vertical: width_value,
+                    }))));
+        }
+
+
+        let size = if self.is_htmlinputelement() {
+            // FIXME(pcwalton): More use of atoms, please!
+            // FIXME(Ms2ger): this is nonsense! Invalid values also end up as
+            //                a text field
+            match self.get_attr_val_for_layout(&ns!(""), &atom!("type")) {
+                Some("text") | Some("password") => {
+                    let this: &HTMLInputElement = mem::transmute(self);
+                    match this.get_size_for_layout() {
+                        0 => None,
+                        s => Some(s as i32),
+                    }
                 }
+                _ => None
             }
+        } else {
+            None
+        };
+
+        if let Some(size) = size {
+            let value = specified::Length::ServoCharacterWidth(
+                specified::CharacterWidth(size));
+            hints.push(from_declaration(
+                PropertyDeclaration::Width(SpecifiedValue(
+                    specified::LengthOrPercentageOrAuto::Length(value)))));
         }
-    }
 
-    #[inline]
-    unsafe fn get_integer_attribute_for_layout(&self, integer_attribute: IntegerAttribute)
-                                               -> Option<i32> {
-        match integer_attribute {
-            IntegerAttribute::Size => {
-                if !self.is_htmlinputelement() {
-                    panic!("I'm not a form input!")
-                }
-                let this: &HTMLInputElement = mem::transmute(self);
-                Some(this.get_size_for_layout() as i32)
+
+        let width = if self.is_htmltableelement() {
+            let this: &HTMLTableElement = mem::transmute(self);
+            this.get_width()
+        } else if self.is_htmltabledatacellelement() {
+            let this: &HTMLTableCellElement = mem::transmute(self);
+            this.get_width()
+        } else {
+            LengthOrPercentageOrAuto::Auto
+        };
+
+        match width {
+            LengthOrPercentageOrAuto::Auto => {}
+            LengthOrPercentageOrAuto::Percentage(percentage) => {
+                let width_value = specified::LengthOrPercentageOrAuto::Percentage(percentage);
+                hints.push(from_declaration(
+                    PropertyDeclaration::Width(SpecifiedValue(width_value))));
             }
-            IntegerAttribute::Cols => {
-                if !self.is_htmltextareaelement() {
-                    panic!("I'm not a textarea element!")
-                }
-                let this: &HTMLTextAreaElement = mem::transmute(self);
-                Some(this.get_cols_for_layout() as i32)
+            LengthOrPercentageOrAuto::Length(length) => {
+                let width_value = specified::LengthOrPercentageOrAuto::Length(specified::Length::Absolute(length));
+                hints.push(from_declaration(
+                    PropertyDeclaration::Width(SpecifiedValue(width_value))));
             }
-            IntegerAttribute::Rows => {
-                if !self.is_htmltextareaelement() {
-                    panic!("I'm not a textarea element!")
-                }
-                let this: &HTMLTextAreaElement = mem::transmute(self);
-                Some(this.get_rows_for_layout() as i32)
+        }
+
+
+        let cols = if self.is_htmltextareaelement() {
+            let this: &HTMLTextAreaElement = mem::transmute(self);
+            match this.get_cols_for_layout() {
+                0 => None,
+                c => Some(c as i32),
             }
+        } else {
+            None
+        };
+
+        if let Some(cols) = cols {
+            // TODO(mttr) ServoCharacterWidth uses the size math for <input type="text">, but
+            // the math for <textarea> is a little different since we need to take
+            // scrollbar size into consideration (but we don't have a scrollbar yet!)
+            //
+            // https://html.spec.whatwg.org/multipage/#textarea-effective-width
+            let value = specified::Length::ServoCharacterWidth(specified::CharacterWidth(cols));
+            hints.push(from_declaration(
+                PropertyDeclaration::Width(SpecifiedValue(
+                    specified::LengthOrPercentageOrAuto::Length(value)))));
+        }
+
+
+        let rows = if self.is_htmltextareaelement() {
+            let this: &HTMLTextAreaElement = mem::transmute(self);
+            match this.get_rows_for_layout() {
+                0 => None,
+                r => Some(r as i32),
+            }
+        } else {
+            None
+        };
+
+        if let Some(rows) = rows {
+            // TODO(mttr) This should take scrollbar size into consideration.
+            //
+            // https://html.spec.whatwg.org/multipage/#textarea-effective-height
+            let value = specified::Length::FontRelative(specified::FontRelativeLength::Em(rows as CSSFloat));
+            hints.push(from_declaration(
+                PropertyDeclaration::Height(SpecifiedValue(
+                    longhands::height::SpecifiedValue(
+                        specified::LengthOrPercentageOrAuto::Length(value))))));
         }
     }
 
@@ -345,16 +413,6 @@ impl RawLayoutElementHelpers for Element {
                     None
                 }
             }
-            UnsignedIntegerAttribute::CellSpacing => {
-                if self.is_htmltableelement() {
-                    let this: &HTMLTableElement = mem::transmute(self);
-                    this.get_cellspacing()
-                } else {
-                    // Don't panic since `display` can cause this to be called on arbitrary
-                    // elements.
-                    None
-                }
-            }
             UnsignedIntegerAttribute::ColSpan => {
                 if self.is_htmltablecellelement() {
                     let this: &HTMLTableCellElement = mem::transmute(self);
diff --git a/components/style/legacy.rs b/components/style/legacy.rs
index b10376981a8..4d6e89756af 100644
--- a/components/style/legacy.rs
+++ b/components/style/legacy.rs
@@ -10,39 +10,20 @@ use std::sync::Arc;
 use selectors::tree::{TElement, TNode};
 use selectors::matching::DeclarationBlock;
 use node::TElementAttributes;
-use values::{CSSFloat, specified};
+use values::specified;
 use properties::DeclaredValue::SpecifiedValue;
 use properties::PropertyDeclaration;
-use properties::longhands::{self, border_spacing};
+use properties::longhands;
 use selector_matching::Stylist;
 
 use util::geometry::Au;
 use util::smallvec::VecLike;
-use util::str::LengthOrPercentageOrAuto;
-
-/// Legacy presentational attributes that take a length as defined in HTML5 § 2.4.4.4.
-#[derive(Copy, Clone, PartialEq, Eq)]
-pub enum LengthAttribute {
-    /// `<td width>`
-    Width,
-}
-
-/// Legacy presentational attributes that take an integer as defined in HTML5 § 2.4.4.2.
-#[derive(Copy, Clone, PartialEq, Eq)]
-pub enum IntegerAttribute {
-    /// `<input size>`
-    Size,
-    Cols,
-    Rows,
-}
 
 /// Legacy presentational attributes that take a nonnegative integer as defined in HTML5 § 2.4.4.2.
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub enum UnsignedIntegerAttribute {
     /// `<td border>`
     Border,
-    /// `<table cellspacing>`
-    CellSpacing,
     /// `<td colspan>`
     ColSpan,
 }
@@ -75,14 +56,6 @@ pub trait PresentationalHintSynthesis {
                                                                     E: TElement<'a> +
                                                                        TElementAttributes<'a>,
                                                                     V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
-    /// Synthesizes rules for the legacy `width` attribute.
-    fn synthesize_presentational_hint_for_legacy_width_attribute<'a,E,V>(
-            &self,
-            element: E,
-            matching_rules_list: &mut V,
-            shareable: &mut bool)
-            where E: TElement<'a> + TElementAttributes<'a>,
-                  V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
 }
 
 impl PresentationalHintSynthesis for Stylist {
@@ -105,89 +78,16 @@ impl PresentationalHintSynthesis for Stylist {
 
         match element.get_local_name() {
             name if *name == atom!("td") => {
-                self.synthesize_presentational_hint_for_legacy_width_attribute(
-                    element,
-                    matching_rules_list,
-                    shareable);
                 self.synthesize_presentational_hint_for_legacy_border_attribute(
                     element,
                     matching_rules_list,
                     shareable);
             }
             name if *name == atom!("table") => {
-                self.synthesize_presentational_hint_for_legacy_width_attribute(
-                    element,
-                    matching_rules_list,
-                    shareable);
                 self.synthesize_presentational_hint_for_legacy_border_attribute(
                     element,
                     matching_rules_list,
                     shareable);
-                match element.get_unsigned_integer_attribute(
-                        UnsignedIntegerAttribute::CellSpacing) {
-                    None => {}
-                    Some(length) => {
-                        let width_value = specified::Length::Absolute(Au::from_px(length as i32));
-                        matching_rules_list.push(from_declaration(
-                                PropertyDeclaration::BorderSpacing(
-                                    SpecifiedValue(
-                                        border_spacing::SpecifiedValue {
-                                            horizontal: width_value,
-                                            vertical: width_value,
-                                        }))));
-                        *shareable = false
-                    }
-                }
-            }
-            name if *name == atom!("input") => {
-                // FIXME(pcwalton): More use of atoms, please!
-                match element.get_attr(&ns!(""), &atom!("type")) {
-                    Some("text") | Some("password") => {
-                        match element.get_integer_attribute(IntegerAttribute::Size) {
-                            Some(value) if value != 0 => {
-                                let value = specified::Length::ServoCharacterWidth(
-                                    specified::CharacterWidth(value));
-                                matching_rules_list.push(from_declaration(
-                                        PropertyDeclaration::Width(SpecifiedValue(
-                                            specified::LengthOrPercentageOrAuto::Length(value)))));
-                                *shareable = false
-                            }
-                            Some(_) | None => {}
-                        }
-                    }
-                    _ => {}
-                };
-            }
-            name if *name == atom!("textarea") => {
-                match element.get_integer_attribute(IntegerAttribute::Cols) {
-                    Some(value) if value != 0 => {
-                        // TODO(mttr) ServoCharacterWidth uses the size math for <input type="text">, but
-                        // the math for <textarea> is a little different since we need to take
-                        // scrollbar size into consideration (but we don't have a scrollbar yet!)
-                        //
-                        // https://html.spec.whatwg.org/multipage/#textarea-effective-width
-                        let value = specified::Length::ServoCharacterWidth(specified::CharacterWidth(value));
-                        matching_rules_list.push(from_declaration(
-                                PropertyDeclaration::Width(SpecifiedValue(
-                                    specified::LengthOrPercentageOrAuto::Length(value)))));
-                        *shareable = false
-                    }
-                    Some(_) | None => {}
-                }
-                match element.get_integer_attribute(IntegerAttribute::Rows) {
-                    Some(value) if value != 0 => {
-                        // TODO(mttr) This should take scrollbar size into consideration.
-                        //
-                        // https://html.spec.whatwg.org/multipage/#textarea-effective-height
-                        let value = specified::Length::FontRelative(specified::FontRelativeLength::Em(value as CSSFloat));
-                        matching_rules_list.push(from_declaration(
-                                PropertyDeclaration::Height(SpecifiedValue(
-                                    longhands::height::SpecifiedValue(
-                                        specified::LengthOrPercentageOrAuto::Length(value))))));
-                        *shareable = false
-                    }
-                    Some(_) | None => {}
-                }
             }
             _ => {}
         }
@@ -222,31 +122,6 @@ impl PresentationalHintSynthesis for Stylist {
             }
         }
     }
-
-    fn synthesize_presentational_hint_for_legacy_width_attribute<'a,E,V>(
-            &self,
-            element: E,
-            matching_rules_list: &mut V,
-            shareable: &mut bool)
-            where E: TElement<'a> + TElementAttributes<'a>,
-                  V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>> {
-        match element.get_length_attribute(LengthAttribute::Width) {
-            LengthOrPercentageOrAuto::Auto => {}
-            LengthOrPercentageOrAuto::Percentage(percentage) => {
-                let width_value = specified::LengthOrPercentageOrAuto::Percentage(percentage);
-                matching_rules_list.push(from_declaration(
-                        PropertyDeclaration::Width(SpecifiedValue(width_value))));
-                *shareable = false
-            }
-            LengthOrPercentageOrAuto::Length(length) => {
-                let width_value = specified::LengthOrPercentageOrAuto::Length(
-                    specified::Length::Absolute(length));
-                matching_rules_list.push(from_declaration(
-                        PropertyDeclaration::Width(SpecifiedValue(width_value))));
-                *shareable = false
-            }
-        }
-    }
 }
 
 
diff --git a/components/style/node.rs b/components/style/node.rs
index ebfcf7d9068..dfe0913e12a 100644
--- a/components/style/node.rs
+++ b/components/style/node.rs
@@ -5,10 +5,9 @@
 //! Traits that nodes must implement. Breaks the otherwise-cyclic dependency between layout and
 //! style.
 
-use legacy::{IntegerAttribute, LengthAttribute, UnsignedIntegerAttribute};
+use legacy::UnsignedIntegerAttribute;
 use properties::PropertyDeclaration;
 use util::smallvec::VecLike;
-use util::str::LengthOrPercentageOrAuto;
 
 use selectors::matching::DeclarationBlock;
 pub use selectors::tree::{TNode, TElement};
@@ -17,8 +16,6 @@ use string_cache::{Atom, Namespace};
 pub trait TElementAttributes<'a> : Copy {
     fn synthesize_presentational_hints_for_legacy_attributes<V>(self, &mut V)
         where V: VecLike<DeclarationBlock<Vec<PropertyDeclaration>>>;
-    fn get_length_attribute(self, attribute: LengthAttribute) -> LengthOrPercentageOrAuto;
-    fn get_integer_attribute(self, attribute: IntegerAttribute) -> Option<i32>;
     fn get_unsigned_integer_attribute(self, attribute: UnsignedIntegerAttribute) -> Option<u32>;
 
     fn get_attr(self, namespace: &Namespace, attr: &Atom) -> Option<&'a str>;