Auto merge of #19838 - servo:rm-sequence-writer-as-it-was, r=emilio

Make ToCss' SequenceWriter not monomorphise like a maniac anymore

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components/script/dom/medialist.rs

@@ -93,12 +93,11 @@ impl MediaListMethods for MediaList {
     // https://drafts.csswg.org/cssom/#dom-medialist-item
     fn Item(&self, index: u32) -> Option<DOMString> {
         let guard = self.shared_lock().read();
-        self.media_queries.read_with(&guard).media_queries
-        .get(index as usize).and_then(|query| {
-            let mut s = String::new();
-            query.to_css(&mut s).unwrap();
-            Some(DOMString::from_string(s))
-        })
+        self.media_queries
+            .read_with(&guard)
+            .media_queries
+            .get(index as usize)
+            .map(|query| query.to_css_string().into())
     }
 
     // https://drafts.csswg.org/cssom/#dom-medialist-item

components/script/dom/mediaquerylist.rs

@@ -83,9 +83,7 @@ impl MediaQueryList {
 impl MediaQueryListMethods for MediaQueryList {
     // https://drafts.csswg.org/cssom-view/#dom-mediaquerylist-media
     fn Media(&self) -> DOMString {
-        let mut s = String::new();
-        self.media_query_list.to_css(&mut s).unwrap();
-        DOMString::from_string(s)
+        self.media_query_list.to_css_string().into()
     }
 
     // https://drafts.csswg.org/cssom-view/#dom-mediaquerylist-matches

components/style/counter_style/mod.rs

@@ -20,7 +20,8 @@ use std::borrow::Cow;
 use std::fmt::{self, Write};
 use std::ops::Range;
 use str::CssStringWriter;
-use style_traits::{Comma, OneOrMoreSeparated, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{Comma, CssWriter, OneOrMoreSeparated, ParseError};
+use style_traits::{StyleParseErrorKind, ToCss};
 use values::CustomIdent;
 
 /// Parse a counter style name reference.
@@ -231,12 +232,12 @@ macro_rules! counter_style_descriptors {
         impl ToCssWithGuard for CounterStyleRuleData {
             fn to_css(&self, _guard: &SharedRwLockReadGuard, dest: &mut CssStringWriter) -> fmt::Result {
                 dest.write_str("@counter-style ")?;
-                self.name.to_css(dest)?;
+                self.name.to_css(&mut CssWriter::new(dest))?;
                 dest.write_str(" {\n")?;
                 $(
                     if let Some(ref value) = self.$ident {
                         dest.write_str(concat!("  ", $name, ": "))?;
-                        ToCss::to_css(value, dest)?;
+                        ToCss::to_css(value, &mut CssWriter::new(dest))?;
                         dest.write_str(";\n")?;
                     }
                 )+
@@ -362,7 +363,10 @@ impl Parse for System {
 }
 
 impl ToCss for System {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
         match *self {
             System::Cyclic => dest.write_str("cyclic"),
             System::Numeric => dest.write_str("numeric"),
@@ -410,7 +414,10 @@ impl Parse for Symbol {
 }
 
 impl ToCss for Symbol {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
         match *self {
             Symbol::String(ref s) => s.to_css(dest),
             Symbol::Ident(ref s) => serialize_identifier(s, dest),
@@ -477,7 +484,10 @@ fn parse_bound<'i, 't>(input: &mut Parser<'i, 't>) -> Result<Option<i32>, ParseE
 }
 
 impl ToCss for Ranges {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
         let mut iter = self.0.iter();
         if let Some(first) = iter.next() {
             range_to_css(first, dest)?;
@@ -492,14 +502,19 @@ impl ToCss for Ranges {
     }
 }
 
-fn range_to_css<W>(range: &Range<Option<i32>>, dest: &mut W) -> fmt::Result
-where W: fmt::Write {
+fn range_to_css<W>(range: &Range<Option<i32>>, dest: &mut CssWriter<W>) -> fmt::Result
+where
+    W: Write,
+{
     bound_to_css(range.start, dest)?;
     dest.write_char(' ')?;
     bound_to_css(range.end, dest)
 }
 
-fn bound_to_css<W>(range: Option<i32>, dest: &mut W) -> fmt::Result where W: fmt::Write {
+fn bound_to_css<W>(range: Option<i32>, dest: &mut CssWriter<W>) -> fmt::Result
+where
+    W: Write,
+{
     if let Some(finite) = range {
         finite.to_css(dest)
     } else {
@@ -556,7 +571,10 @@ impl Parse for Symbols {
 }
 
 impl ToCss for Symbols {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
         let mut iter = self.0.iter();
         let first = iter.next().expect("expected at least one symbol");
         first.to_css(dest)?;

components/style/custom_properties.rs

@@ -17,9 +17,9 @@ use smallvec::SmallVec;
 #[allow(unused_imports)] use std::ascii::AsciiExt;
 use std::borrow::{Borrow, Cow};
 use std::cmp;
-use std::fmt;
+use std::fmt::{self, Write};
 use std::hash::Hash;
-use style_traits::{ToCss, StyleParseErrorKind, ParseError};
+use style_traits::{CssWriter, ToCss, StyleParseErrorKind, ParseError};
 
 /// A custom property name is just an `Atom`.
 ///
@@ -53,8 +53,9 @@ pub struct VariableValue {
 }
 
 impl ToCss for SpecifiedValue {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
-        where W: fmt::Write,
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
     {
         dest.write_str(&self.css)
     }

components/style/font_face.rs

@@ -22,7 +22,8 @@ use selectors::parser::SelectorParseErrorKind;
 use shared_lock::{SharedRwLockReadGuard, ToCssWithGuard};
 use std::fmt::{self, Write};
 use str::CssStringWriter;
-use style_traits::{Comma, OneOrMoreSeparated, ParseError, StyleParseErrorKind, ToCss};
+use style_traits::{Comma, CssWriter, OneOrMoreSeparated, ParseError};
+use style_traits::{StyleParseErrorKind, ToCss};
 use values::computed::font::FamilyName;
 use values::specified::url::SpecifiedUrl;
 
@@ -55,8 +56,9 @@ pub struct UrlSource {
 }
 
 impl ToCss for UrlSource {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
-        where W: fmt::Write,
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
     {
         self.url.to_css(dest)
     }
@@ -278,7 +280,7 @@ macro_rules! font_face_descriptors_common {
                 $(
                     if let Some(ref value) = self.$ident {
                         dest.write_str(concat!("  ", $name, ": "))?;
-                        ToCss::to_css(value, dest)?;
+                        ToCss::to_css(value, &mut CssWriter::new(dest))?;
                         dest.write_str(";\n")?;
                     }
                 )*

components/style/gecko/media_queries.rs

@@ -24,7 +24,7 @@ use std::fmt::{self, Write};
 use std::sync::atomic::{AtomicBool, AtomicIsize, AtomicUsize, Ordering};
 use str::starts_with_ignore_ascii_case;
 use string_cache::Atom;
-use style_traits::{CSSPixel, DevicePixel};
+use style_traits::{CSSPixel, CssWriter, DevicePixel};
 use style_traits::{ToCss, ParseError, StyleParseErrorKind};
 use style_traits::viewport::ViewportConstraints;
 use stylesheets::Origin;
@@ -236,7 +236,7 @@ pub struct Expression {
 }
 
 impl ToCss for Expression {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
         where W: fmt::Write,
     {
         dest.write_str("(")?;
@@ -408,7 +408,7 @@ impl MediaExpressionValue {
 }
 
 impl MediaExpressionValue {
-    fn to_css<W>(&self, dest: &mut W, for_expr: &Expression) -> fmt::Result
+    fn to_css<W>(&self, dest: &mut CssWriter<W>, for_expr: &Expression) -> fmt::Result
         where W: fmt::Write,
     {
         match *self {

components/style/gecko/selector_parser.rs

@@ -16,7 +16,7 @@ use selectors::parser::{self as selector_parser, Selector, Visit, SelectorParseE
 use selectors::visitor::SelectorVisitor;
 use std::fmt;
 use string_cache::{Atom, Namespace, WeakAtom, WeakNamespace};
-use style_traits::{ParseError, StyleParseErrorKind, ToCss as ToCss_};
+use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss as ToCss_};
 
 pub use gecko::pseudo_element::{PseudoElement, EAGER_PSEUDOS, EAGER_PSEUDO_COUNT, PSEUDO_COUNT};
 pub use gecko::snapshot::SnapshotMap;
@@ -86,12 +86,12 @@ impl ToCss for NonTSPseudoClass {
                     }, )*
                     NonTSPseudoClass::MozLocaleDir(ref dir) => {
                         dest.write_str(":-moz-locale-dir(")?;
-                        dir.to_css(dest)?;
+                        dir.to_css(&mut CssWriter::new(dest))?;
                         return dest.write_char(')')
                     },
                     NonTSPseudoClass::Dir(ref dir) => {
                         dest.write_str(":dir(")?;
-                        dir.to_css(dest)?;
+                        dir.to_css(&mut CssWriter::new(dest))?;
                         return dest.write_char(')')
                     },
                     NonTSPseudoClass::MozAny(ref selectors) => {

components/style/gecko/url.rs

@@ -12,9 +12,9 @@ use gecko_bindings::sugar::refptr::RefPtr;
 use malloc_size_of::{MallocSizeOf, MallocSizeOfOps};
 use parser::ParserContext;
 use servo_arc::{Arc, RawOffsetArc};
-use std::fmt;
+use std::fmt::{self, Write};
 use std::mem;
-use style_traits::{ToCss, ParseError};
+use style_traits::{CssWriter, ToCss, ParseError};
 
 /// A specified url() value for gecko. Gecko does not eagerly resolve SpecifiedUrls.
 #[derive(Clone, Debug, PartialEq)]
@@ -136,7 +136,10 @@ impl SpecifiedUrl {
 }
 
 impl ToCss for SpecifiedUrl {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
+    {
         dest.write_str("url(")?;
         self.serialization.to_css(dest)?;
         dest.write_str(")")

components/style/lib.rs

@@ -134,8 +134,8 @@ pub mod traversal_flags;
 #[allow(non_camel_case_types)]
 pub mod values;
 
-use std::fmt;
-use style_traits::ToCss;
+use std::fmt::{self, Write};
+use style_traits::{CssWriter, ToCss};
 
 #[cfg(feature = "gecko")] pub use gecko_string_cache as string_cache;
 #[cfg(feature = "gecko")] pub use gecko_string_cache::Atom;
@@ -181,11 +181,13 @@ longhand_properties_idents!(reexport_computed_values);
 
 /// Serializes as CSS a comma-separated list of any `T` that supports being
 /// serialized as CSS.
-pub fn serialize_comma_separated_list<W, T>(dest: &mut W,
-                                            list: &[T])
-                                            -> fmt::Result
-    where W: fmt::Write,
-          T: ToCss,
+pub fn serialize_comma_separated_list<W, T>(
+    dest: &mut CssWriter<W>,
+    list: &[T],
+) -> fmt::Result
+where
+    W: Write,
+    T: ToCss,
 {
     if list.is_empty() {
         return Ok(());

components/style/macros.rs

@@ -91,8 +91,11 @@ macro_rules! define_numbered_css_keyword_enum {
             }
         }
 
-        impl ::style_traits::values::ToCss for $name {
-            fn to_css<W>(&self, dest: &mut W) -> ::std::fmt::Result
+        impl ::style_traits::ToCss for $name {
+            fn to_css<W>(
+                &self,
+                dest: &mut ::style_traits::CssWriter<W>,
+            ) -> ::std::fmt::Result
             where
                 W: ::std::fmt::Write,
             {

components/style/media_queries.rs

@@ -14,9 +14,9 @@ use error_reporting::{ContextualParseError, ParseErrorReporter};
 use parser::{ParserContext, ParserErrorContext};
 use selectors::parser::SelectorParseErrorKind;
 use serialize_comma_separated_list;
-use std::fmt;
+use std::fmt::{self, Write};
 use str::string_as_ascii_lowercase;
-use style_traits::{ToCss, ParseError, StyleParseErrorKind};
+use style_traits::{CssWriter, ToCss, ParseError, StyleParseErrorKind};
 use values::CustomIdent;
 
 #[cfg(feature = "servo")]
@@ -33,8 +33,9 @@ pub struct MediaList {
 }
 
 impl ToCss for MediaList {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
-        where W: fmt::Write
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
     {
         serialize_comma_separated_list(dest, &self.media_queries)
     }
@@ -86,8 +87,9 @@ impl MediaQuery {
 }
 
 impl ToCss for MediaQuery {
-    fn to_css<W>(&self, dest: &mut W) -> fmt::Result
-        where W: fmt::Write,
+    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
+    where
+        W: Write,
     {
         if let Some(qual) = self.qualifier {
             qual.to_css(dest)?;