Auto merge of #12924 - servo:selectors-ser, r=nox

Update selectors to 0.10, with ToCss serialization.

<!-- Please describe your changes on the following line: -->
r? @emilio

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [ ] These changes fix #__ (github issue number if applicable).

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- [x] There are tests for these changes OR
- [ ] These changes do not require tests because _____

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This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/12924)
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22 files changed, 203 insertions, 69 deletions

diff --git a/components/layout/Cargo.toml b/components/layout/Cargo.toml
index 5b6baf33845..0ac6e869864 100644
--- a/components/layout/Cargo.toml
+++ b/components/layout/Cargo.toml
@@ -33,7 +33,7 @@ range = {path = "../range"}
 rustc-serialize = "0.3"
 script_layout_interface = {path = "../script_layout_interface"}
 script_traits = {path = "../script_traits"}
-selectors = {version = "0.9", features = ["heap_size"]}
+selectors = {version = "0.10", features = ["heap_size"]}
 serde_macros = "0.8"
 smallvec = "0.1"
 string_cache = {version = "0.2.23", features = ["heap_size"]}
diff --git a/components/script/Cargo.toml b/components/script/Cargo.toml
index 91c7a7fd2f6..a2e8d3a28f8 100644
--- a/components/script/Cargo.toml
+++ b/components/script/Cargo.toml
@@ -62,7 +62,7 @@ regex = "0.1.43"
 rustc-serialize = "0.3"
 script_layout_interface = {path = "../script_layout_interface"}
 script_traits = {path = "../script_traits"}
-selectors = {version = "0.9", features = ["heap_size"]}
+selectors = {version = "0.10", features = ["heap_size"]}
 serde = "0.8"
 smallvec = "0.1"
 string_cache = {version = "0.2.23", features = ["heap_size", "unstable"]}
diff --git a/components/script/dom/element.rs b/components/script/dom/element.rs
index f74f253aa78..860818c024c 100644
--- a/components/script/dom/element.rs
+++ b/components/script/dom/element.rs
@@ -2250,7 +2250,7 @@ impl<'a> ::selectors::MatchAttrGeneric for Root<Element> {
         };
         match attr.namespace {
             NamespaceConstraint::Specific(ref ns) => {
-                self.get_attribute(ns, local_name)
+                self.get_attribute(&ns.url, local_name)
                     .map_or(false, |attr| {
                         test(&attr.value())
                     })
diff --git a/components/script/layout_wrapper.rs b/components/script/layout_wrapper.rs
index 13fcdc41df9..cbf04b48e5b 100644
--- a/components/script/layout_wrapper.rs
+++ b/components/script/layout_wrapper.rs
@@ -483,7 +483,7 @@ impl<'le> ::selectors::MatchAttrGeneric for ServoLayoutElement<'le> {
         };
         match attr.namespace {
             NamespaceConstraint::Specific(ref ns) => {
-                self.get_attr(ns, name).map_or(false, |attr| test(attr))
+                self.get_attr(&ns.url, name).map_or(false, |attr| test(attr))
             },
             NamespaceConstraint::Any => {
                 let attrs = unsafe {
@@ -970,7 +970,7 @@ impl<'le> ::selectors::MatchAttrGeneric for ServoThreadSafeLayoutElement<'le> {
         where F: Fn(&str) -> bool {
         match attr.namespace {
             NamespaceConstraint::Specific(ref ns) => {
-                self.get_attr(ns, &attr.name).map_or(false, |attr| test(attr))
+                self.get_attr(&ns.url, &attr.name).map_or(false, |attr| test(attr))
             },
             NamespaceConstraint::Any => {
                 unsafe {
diff --git a/components/script_layout_interface/Cargo.toml b/components/script_layout_interface/Cargo.toml
index b2ec16ab3e6..bd4ac66f410 100644
--- a/components/script_layout_interface/Cargo.toml
+++ b/components/script_layout_interface/Cargo.toml
@@ -27,7 +27,7 @@ plugins = {path = "../plugins"}
 profile_traits = {path = "../profile_traits"}
 range = {path = "../range"}
 script_traits = {path = "../script_traits"}
-selectors = {version = "0.9", features = ["heap_size"]}
+selectors = {version = "0.10", features = ["heap_size"]}
 string_cache = {version = "0.2.23", features = ["heap_size"]}
 style = {path = "../style"}
 url = {version = "1.2", features = ["heap_size"]}
diff --git a/components/servo/Cargo.lock b/components/servo/Cargo.lock
index 152277c7189..2b4bb06119a 100644
--- a/components/servo/Cargo.lock
+++ b/components/servo/Cargo.lock
@@ -790,7 +790,7 @@ dependencies = [
  "servo-fontconfig 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "simd 0.1.0 (git+https://github.com/huonw/simd)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -956,7 +956,7 @@ dependencies = [
  "phf 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1162,10 +1162,10 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_layout_interface 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "unicode-bidi 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1931,10 +1931,10 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_layout_interface 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "tinyfiledialogs 0.1.0 (git+https://github.com/jdm/tinyfiledialogs)",
@@ -1967,8 +1967,8 @@ dependencies = [
  "profile_traits 0.0.1",
  "range 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -2016,7 +2016,7 @@ dependencies = [
 
 [[package]]
 name = "selectors"
-version = "0.9.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2027,7 +2027,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickersort 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2204,7 +2204,7 @@ dependencies = [
 
 [[package]]
 name = "string_cache"
-version = "0.2.23"
+version = "0.2.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "debug_unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2238,11 +2238,11 @@ dependencies = [
  "plugins 0.0.1",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2258,8 +2258,8 @@ dependencies = [
  "cssparser 0.5.7 (registry+https://github.com/rust-lang/crates.io-index)",
  "euclid 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2698,7 +2698,7 @@ dependencies = [
  "phf 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/components/style/Cargo.toml b/components/style/Cargo.toml
index 91693e26069..000803d2777 100644
--- a/components/style/Cargo.toml
+++ b/components/style/Cargo.toml
@@ -38,11 +38,11 @@ num-traits = "0.1.32"
 ordered-float = "0.2.2"
 rand = "0.3"
 rustc-serialize = "0.3"
-selectors = "0.9"
+selectors = "0.10.1"
 serde = {version = "0.8", optional = true}
 serde_macros = {version = "0.8", optional = true}
 smallvec = "0.1"
-string_cache = {version = "0.2.23", features = ["heap_size"], optional = true}
+string_cache = {version = "0.2.24", features = ["heap_size"], optional = true}
 style_traits = {path = "../style_traits"}
 time = "0.1"
 url = "1.2"
diff --git a/components/style/gecko_selector_impl.rs b/components/style/gecko_selector_impl.rs
index d78349af2aa..611e79eddcc 100644
--- a/components/style/gecko_selector_impl.rs
+++ b/components/style/gecko_selector_impl.rs
@@ -2,10 +2,12 @@
  * 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 cssparser::ToCss;
 use element_state::ElementState;
 use selector_impl::PseudoElementCascadeType;
 use selector_impl::{attr_exists_selector_is_shareable, attr_equals_selector_is_shareable};
 use selectors::parser::{ParserContext, SelectorImpl, AttrSelector};
+use std::fmt;
 use string_cache::{Atom, WeakAtom, Namespace, WeakNamespace};
 use stylesheets::Stylesheet;
 
@@ -93,6 +95,16 @@ impl PseudoElement {
     }
 }
 
+impl ToCss for PseudoElement {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        // FIXME: why does the atom contain one colon? Pseudo-element has two
+        debug_assert!(self.0.as_slice().starts_with(&[b':' as u16]) &&
+                      !self.0.as_slice().starts_with(&[b':' as u16, b':' as u16]));
+        try!(dest.write_char(':'));
+        write!(dest, "{}", self.0)
+    }
+}
+
 #[derive(Clone, Debug, PartialEq, Eq, Hash)]
 pub enum NonTSPseudoClass {
     AnyLink,
@@ -109,6 +121,26 @@ pub enum NonTSPseudoClass {
     ReadOnly,
 }
 
+impl ToCss for NonTSPseudoClass {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use self::NonTSPseudoClass::*;
+        dest.write_str(match *self {
+            AnyLink => ":any-link",
+            Link => ":link",
+            Visited => ":visited",
+            Active => ":active",
+            Focus => ":focus",
+            Hover => ":hover",
+            Enabled => ":enabled",
+            Disabled => ":disabled",
+            Checked => ":checked",
+            Indeterminate => ":indeterminate",
+            ReadWrite => ":read-write",
+            ReadOnly => ":read-only",
+        })
+    }
+}
+
 impl NonTSPseudoClass {
     pub fn state_flag(&self) -> ElementState {
         use element_state::*;
@@ -135,8 +167,9 @@ impl SelectorImpl for GeckoSelectorImpl {
     type Identifier = Atom;
     type ClassName = Atom;
     type LocalName = Atom;
-    type Namespace = Namespace;
-    type BorrowedNamespace = WeakNamespace;
+    type NamespacePrefix = Atom;
+    type NamespaceUrl = Namespace;
+    type BorrowedNamespaceUrl = WeakNamespace;
     type BorrowedLocalName = WeakAtom;
 
     type PseudoElement = PseudoElement;
diff --git a/components/style/properties/properties.mako.rs b/components/style/properties/properties.mako.rs
index 7b19126aeb6..aaf9ddfe88c 100644
--- a/components/style/properties/properties.mako.rs
+++ b/components/style/properties/properties.mako.rs
@@ -468,7 +468,7 @@ fn append_serialization<'a, W, I>(dest: &mut W,
         return append_declaration_value(dest, appendable_value, is_important);
     }
 
-    write!(dest, "{}:", property_name);
+    try!(write!(dest, "{}:", property_name));
 
     // for normal parsed values, add a space between key: and value
     match &appendable_value {
diff --git a/components/style/restyle_hints.rs b/components/style/restyle_hints.rs
index e0688567550..a876dbf54cc 100644
--- a/components/style/restyle_hints.rs
+++ b/components/style/restyle_hints.rs
@@ -220,7 +220,7 @@ impl<'a, E> Element for ElementWrapper<'a, E>
         self.element.get_local_name()
     }
 
-    fn get_namespace(&self) -> &<Self::Impl as SelectorImpl>::BorrowedNamespace {
+    fn get_namespace(&self) -> &<Self::Impl as SelectorImpl>::BorrowedNamespaceUrl {
         self.element.get_namespace()
     }
 
diff --git a/components/style/servo_selector_impl.rs b/components/style/servo_selector_impl.rs
index fab4315dd9f..f69b1cb9e12 100644
--- a/components/style/servo_selector_impl.rs
+++ b/components/style/servo_selector_impl.rs
@@ -3,6 +3,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use attr::{AttrIdentifier, AttrValue};
+use cssparser::ToCss;
 use element_state::ElementState;
 use error_reporting::StdoutErrorReporter;
 use parser::ParserContextExtraData;
@@ -11,6 +12,7 @@ use selector_impl::{ElementExt, PseudoElementCascadeType, TheSelectorImpl};
 use selector_impl::{attr_exists_selector_is_shareable, attr_equals_selector_is_shareable};
 use selectors::parser::{AttrSelector, ParserContext, SelectorImpl};
 use selectors::{Element, MatchAttrGeneric};
+use std::fmt;
 use std::process;
 use string_cache::{Atom, Namespace};
 use stylesheets::{Stylesheet, Origin};
@@ -28,6 +30,20 @@ pub enum PseudoElement {
     DetailsContent,
 }
 
+impl ToCss for PseudoElement {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use self::PseudoElement::*;
+        dest.write_str(match *self {
+            Before => "::before",
+            After => "::after",
+            Selection => "::selection",
+            DetailsSummary => "::-servo-details-summary",
+            DetailsContent => "::-servo-details-content",
+        })
+    }
+}
+
+
 impl PseudoElement {
     #[inline]
     pub fn is_before_or_after(&self) -> bool {
@@ -70,6 +86,29 @@ pub enum NonTSPseudoClass {
     Target,
 }
 
+impl ToCss for NonTSPseudoClass {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use self::NonTSPseudoClass::*;
+        dest.write_str(match *self {
+            AnyLink => ":any-link",
+            Link => ":link",
+            Visited => ":visited",
+            Active => ":active",
+            Focus => ":focus",
+            Hover => ":hover",
+            Enabled => ":enabled",
+            Disabled => ":disabled",
+            Checked => ":checked",
+            Indeterminate => ":indeterminate",
+            ReadWrite => ":read-write",
+            ReadOnly => ":read-only",
+            PlaceholderShown => ":placeholder-shown",
+            Target => ":target",
+            ServoNonZeroBorder => ":-servo-nonzero-border",
+        })
+    }
+}
+
 impl NonTSPseudoClass {
     pub fn state_flag(&self) -> ElementState {
         use element_state::*;
@@ -106,9 +145,10 @@ impl SelectorImpl for ServoSelectorImpl {
     type Identifier = Atom;
     type ClassName = Atom;
     type LocalName = Atom;
-    type Namespace = Namespace;
+    type NamespacePrefix = Atom;
+    type NamespaceUrl = Namespace;
     type BorrowedLocalName = Atom;
-    type BorrowedNamespace = Namespace;
+    type BorrowedNamespaceUrl = Namespace;
 
     fn attr_exists_selector_is_shareable(attr_selector: &AttrSelector<Self>) -> bool {
         attr_exists_selector_is_shareable(attr_selector)
@@ -283,7 +323,7 @@ impl MatchAttrGeneric for ServoElementSnapshot {
         let html = self.is_html_element_in_html_document;
         let local_name = if html { &attr.lower_name } else { &attr.name };
         match attr.namespace {
-            NamespaceConstraint::Specific(ref ns) => self.get_attr(ns, local_name),
+            NamespaceConstraint::Specific(ref ns) => self.get_attr(&ns.url, local_name),
             NamespaceConstraint::Any => self.get_attr_ignore_ns(local_name),
         }.map_or(false, |v| test(v))
     }
diff --git a/components/style/stylesheets.rs b/components/style/stylesheets.rs
index 25bb03174e0..8d234540adc 100644
--- a/components/style/stylesheets.rs
+++ b/components/style/stylesheets.rs
@@ -58,7 +58,11 @@ pub struct Stylesheet {
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum CSSRule {
     Charset(String),
-    Namespace(Option<String>, Namespace),
+    Namespace {
+        /// `None` for the default Namespace
+        prefix: Option<Atom>,
+        url: Namespace,
+    },
     Style(StyleRule),
     Media(MediaRule),
     FontFace(FontFaceRule),
@@ -143,13 +147,13 @@ impl Stylesheet {
             while let Some(result) = iter.next() {
                 match result {
                     Ok(rule) => {
-                        if let CSSRule::Namespace(ref prefix, ref namespace) = rule {
+                        if let CSSRule::Namespace { ref prefix, ref url } = rule {
                             if let Some(prefix) = prefix.as_ref() {
                                 iter.parser.context.selector_context.namespace_prefixes.insert(
-                                    prefix.clone(), namespace.clone());
+                                    prefix.clone(), url.clone());
                             } else {
                                 iter.parser.context.selector_context.default_namespace =
-                                    Some(namespace.clone());
+                                    Some(url.clone());
                             }
                         }
 
@@ -435,9 +439,12 @@ impl<'a> AtRuleParser for TopLevelRuleParser<'a> {
                 if self.state.get() <= State::Namespaces {
                     self.state.set(State::Namespaces);
 
-                    let prefix = input.try(|input| input.expect_ident()).ok().map(|p| p.into_owned());
+                    let prefix = input.try(|input| input.expect_ident()).ok().map(|p| p.into());
                     let url = Namespace(Atom::from(try!(input.expect_url_or_string())));
-                    return Ok(AtRuleType::WithoutBlock(CSSRule::Namespace(prefix, url)))
+                    return Ok(AtRuleType::WithoutBlock(CSSRule::Namespace {
+                        prefix: prefix,
+                        url: url,
+                    }))
                 } else {
                     return Err(())  // "@namespace must be before any rule but @charset and @import"
                 }
diff --git a/ports/cef/Cargo.lock b/ports/cef/Cargo.lock
index 5855f98d9e0..32456904fff 100644
--- a/ports/cef/Cargo.lock
+++ b/ports/cef/Cargo.lock
@@ -707,7 +707,7 @@ dependencies = [
  "servo-fontconfig 0.2.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "simd 0.1.0 (git+https://github.com/huonw/simd)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -864,7 +864,7 @@ dependencies = [
  "phf 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
@@ -1070,10 +1070,10 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_layout_interface 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "unicode-bidi 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1783,10 +1783,10 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
  "script_layout_interface 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "tinyfiledialogs 0.1.0 (git+https://github.com/jdm/tinyfiledialogs)",
@@ -1819,8 +1819,8 @@ dependencies = [
  "profile_traits 0.0.1",
  "range 0.0.1",
  "script_traits 0.0.1",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "util 0.0.1",
@@ -1858,7 +1858,7 @@ dependencies = [
 
 [[package]]
 name = "selectors"
-version = "0.9.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -1869,7 +1869,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickersort 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -2087,7 +2087,7 @@ dependencies = [
 
 [[package]]
 name = "string_cache"
-version = "0.2.23"
+version = "0.2.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "debug_unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2121,11 +2121,11 @@ dependencies = [
  "plugins 0.0.1",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_macros 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -2558,7 +2558,7 @@ dependencies = [
  "phf 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "phf_codegen 0.7.16 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
  "tendril 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
diff --git a/ports/geckolib/Cargo.lock b/ports/geckolib/Cargo.lock
index 51fbc37f50b..a920fdf7118 100644
--- a/ports/geckolib/Cargo.lock
+++ b/ports/geckolib/Cargo.lock
@@ -11,7 +11,7 @@ dependencies = [
  "libc 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "log 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "num_cpus 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -170,7 +170,7 @@ dependencies = [
  "gecko_bindings 0.0.1",
  "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "libc 0.2.13 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -311,7 +311,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "selectors"
-version = "0.9.0"
+version = "0.10.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "bitflags 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -320,7 +320,7 @@ dependencies = [
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "quickersort 2.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
- "string_cache 0.2.23 (registry+https://github.com/rust-lang/crates.io-index)",
+ "string_cache 0.2.24 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -335,7 +335,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "string_cache"
-version = "0.2.23"
+version = "0.2.24"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "debug_unreachable 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -367,7 +367,7 @@ dependencies = [
  "ordered-float 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand 0.3.14 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
- "selectors 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "selectors 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "smallvec 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "style_traits 0.0.1",
  "time 0.1.35 (registry+https://github.com/rust-lang/crates.io-index)",
diff --git a/ports/geckolib/Cargo.toml b/ports/geckolib/Cargo.toml
index 603d5d466ea..72eb2c7b0c5 100644
--- a/ports/geckolib/Cargo.toml
+++ b/ports/geckolib/Cargo.toml
@@ -19,7 +19,7 @@ lazy_static = "0.2"
 libc = "0.2"
 log = {version = "0.3.5", features = ["release_max_level_info"]}
 num_cpus = "0.2.2"
-selectors = "0.9"
+selectors = "0.10"
 style = {path = "../../components/style", features = ["gecko"]}
 style_traits = {path = "../../components/style_traits"}
 url = "1.2"
diff --git a/ports/geckolib/string_cache/Cargo.toml b/ports/geckolib/string_cache/Cargo.toml
index 4fd3daf6dfa..6dd2d704896 100644
--- a/ports/geckolib/string_cache/Cargo.toml
+++ b/ports/geckolib/string_cache/Cargo.toml
@@ -14,5 +14,5 @@ cfg-if = "0.1.0"
 gecko_bindings = {version = "0.0.1", path = "../gecko_bindings"}
 heapsize = "0.3.5"
 libc = "0.2"
-selectors = "0.9"
+selectors = "0.10"
 serde = "0.8"
diff --git a/ports/geckolib/string_cache/namespace.rs b/ports/geckolib/string_cache/namespace.rs
index 6aadd0e3203..d3d57285b5a 100644
--- a/ports/geckolib/string_cache/namespace.rs
+++ b/ports/geckolib/string_cache/namespace.rs
@@ -5,6 +5,7 @@
 use gecko_bindings::structs::nsIAtom;
 use selectors::bloom::BloomHash;
 use std::borrow::Borrow;
+use std::fmt;
 use std::ops::Deref;
 use {Atom, WeakAtom};
 
@@ -29,6 +30,12 @@ impl Deref for Namespace {
     }
 }
 
+impl fmt::Display for Namespace {
+    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(w)
+    }
+}
+
 impl Borrow<WeakNamespace> for Namespace {
     #[inline]
     fn borrow(&self) -> &WeakNamespace {
diff --git a/ports/geckolib/wrapper.rs b/ports/geckolib/wrapper.rs
index 5d35acf6ef7..860173820d6 100644
--- a/ports/geckolib/wrapper.rs
+++ b/ports/geckolib/wrapper.rs
@@ -587,7 +587,7 @@ impl AttrSelectorHelpers for AttrSelector<GeckoSelectorImpl> {
     fn ns_or_null(&self) -> *mut nsIAtom {
         match self.namespace {
             NamespaceConstraint::Any => ptr::null_mut(),
-            NamespaceConstraint::Specific(ref ns) => ns.0.as_ptr(),
+            NamespaceConstraint::Specific(ref ns) => ns.url.0.as_ptr(),
         }
     }
 
diff --git a/tests/unit/style/Cargo.toml b/tests/unit/style/Cargo.toml
index 333ccc2574a..22bdc1c86e4 100644
--- a/tests/unit/style/Cargo.toml
+++ b/tests/unit/style/Cargo.toml
@@ -14,7 +14,7 @@ app_units = "0.3"
 cssparser = {version = "0.5.7", features = ["heap_size"]}
 euclid = "0.9"
 rustc-serialize = "0.3"
-selectors = {version = "0.9", features = ["heap_size"]}
+selectors = {version = "0.10", features = ["heap_size"]}
 string_cache = {version = "0.2.23", features = ["heap_size"]}
 style = {path = "../../../components/style"}
 style_traits = {path = "../../../components/style_traits"}
diff --git a/tests/unit/style/parsing/mod.rs b/tests/unit/style/parsing/mod.rs
index c99032417ee..d0989d01582 100644
--- a/tests/unit/style/parsing/mod.rs
+++ b/tests/unit/style/parsing/mod.rs
@@ -15,6 +15,9 @@ fn parse<T, F: Fn(&mut Parser) -> Result<T, ()>>(f: F, s: &str) -> Result<T, ()>
 // This is a macro so that the file/line information
 // is preserved in the panic
 macro_rules! assert_roundtrip {
+    ($fun:expr, $string:expr) => {
+        assert_roundtrip!($fun, $string, $string);
+    };
     ($fun:expr, $input:expr, $output:expr) => {
         let parsed = $crate::parsing::parse($fun, $input)
                         .expect(&format!("Failed to parse {}", $input));
@@ -31,3 +34,4 @@ macro_rules! assert_roundtrip {
 
 mod basic_shape;
 mod position;
+mod selectors;
diff --git a/tests/unit/style/parsing/selectors.rs b/tests/unit/style/parsing/selectors.rs
new file mode 100644
index 00000000000..abd1a3b5e9a
--- /dev/null
+++ b/tests/unit/style/parsing/selectors.rs
@@ -0,0 +1,22 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * 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 cssparser::Parser;
+use selectors::parser::{Selector, ParserContext, parse_selector_list};
+use style::selector_impl::TheSelectorImpl;
+
+fn parse(input: &mut Parser) -> Result<Selector<TheSelectorImpl>, ()> {
+    let mut context = ParserContext::new();
+    context.in_user_agent_stylesheet = true;
+    context.namespace_prefixes.insert("svg".into(), ns!(svg));
+    parse_selector_list(&context, input).map(|mut vec| vec.pop().unwrap())
+}
+
+#[test]
+fn test_selectors() {
+    assert_roundtrip!(parse, "div");
+    assert_roundtrip!(parse, "svg|circle");
+    assert_roundtrip!(parse, "p:before", "p::before");
+    assert_roundtrip!(parse, "[border = \"0\"]:-servo-nonzero-border ~ ::-servo-details-summary");
+}
diff --git a/tests/unit/style/stylesheets.rs b/tests/unit/style/stylesheets.rs
index b388416d803..a816c747876 100644
--- a/tests/unit/style/stylesheets.rs
+++ b/tests/unit/style/stylesheets.rs
@@ -8,7 +8,7 @@ use selectors::parser::*;
 use std::borrow::ToOwned;
 use std::sync::Arc;
 use std::sync::Mutex;
-use string_cache::{Atom, Namespace};
+use string_cache::{Atom, Namespace as NsAtom};
 use style::error_reporting::ParseErrorReporter;
 use style::keyframes::{Keyframe, KeyframeSelector, KeyframePercentage};
 use style::parser::ParserContextExtraData;
@@ -38,13 +38,19 @@ fn test_parse_stylesheet() {
         media: None,
         dirty_on_viewport_size_change: false,
         rules: vec![
-            CSSRule::Namespace(None, Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+            CSSRule::Namespace {
+                prefix: None,
+                url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+            },
             CSSRule::Style(StyleRule {
                 selectors: vec![
                     Selector {
                         compound_selectors: Arc::new(CompoundSelector {
                             simple_selectors: vec![
-                                SimpleSelector::Namespace(Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+                                SimpleSelector::Namespace(Namespace {
+                                    prefix: None,
+                                    url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+                                }),
                                 SimpleSelector::LocalName(LocalName {
                                     name: atom!("input"),
                                     lower_name: atom!("input"),
@@ -52,7 +58,10 @@ fn test_parse_stylesheet() {
                                 SimpleSelector::AttrEqual(AttrSelector {
                                     name: atom!("type"),
                                     lower_name: atom!("type"),
-                                    namespace: NamespaceConstraint::Specific(ns!()),
+                                    namespace: NamespaceConstraint::Specific(Namespace {
+                                        prefix: None,
+                                        url: ns!()
+                                    }),
                                 }, "hidden".to_owned(), CaseSensitivity::CaseInsensitive)
                             ],
                             next: None,
@@ -74,7 +83,10 @@ fn test_parse_stylesheet() {
                     Selector {
                         compound_selectors: Arc::new(CompoundSelector {
                             simple_selectors: vec![
-                                SimpleSelector::Namespace(Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+                                SimpleSelector::Namespace(Namespace {
+                                    prefix: None,
+                                    url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+                                }),
                                 SimpleSelector::LocalName(LocalName {
                                     name: atom!("html"),
                                     lower_name: atom!("html"),
@@ -88,7 +100,10 @@ fn test_parse_stylesheet() {
                     Selector {
                         compound_selectors: Arc::new(CompoundSelector {
                             simple_selectors: vec![
-                                SimpleSelector::Namespace(Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+                                SimpleSelector::Namespace(Namespace {
+                                    prefix: None,
+                                    url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+                                }),
                                 SimpleSelector::LocalName(LocalName {
                                     name: atom!("body"),
                                     lower_name: atom!("body"),
@@ -113,12 +128,18 @@ fn test_parse_stylesheet() {
                     Selector {
                         compound_selectors: Arc::new(CompoundSelector {
                             simple_selectors: vec![
-                                SimpleSelector::Namespace(Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+                                SimpleSelector::Namespace(Namespace {
+                                    prefix: None,
+                                    url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+                                }),
                                 SimpleSelector::Class(Atom::from("ok")),
                             ],
                             next: Some((Arc::new(CompoundSelector {
                                 simple_selectors: vec![
-                                    SimpleSelector::Namespace(Namespace(Atom::from("http://www.w3.org/1999/xhtml"))),
+                                    SimpleSelector::Namespace(Namespace {
+                                        prefix: None,
+                                        url: NsAtom(Atom::from("http://www.w3.org/1999/xhtml"))
+                                    }),
                                     SimpleSelector::ID(Atom::from("d1")),
                                 ],
                                 next: None,