style: Make quotes property representation allocate less.

Differential Revision: https://phabricator.services.mozilla.com/D10650

components/style/properties/gecko.mako.rs

@@ -4187,9 +4187,9 @@ fn static_assert() {
             UniqueRefPtr::from_addrefed(Gecko_NewStyleQuoteValues(other.0.len() as u32))
         };
 
-        for (servo, gecko) in other.0.into_iter().zip(refptr.mQuotePairs.iter_mut()) {
-            gecko.first.assign_str(&servo.0);
-            gecko.second.assign_str(&servo.1);
+        for (servo, gecko) in other.0.iter().zip(refptr.mQuotePairs.iter_mut()) {
+            gecko.first.assign_str(&servo.opening);
+            gecko.second.assign_str(&servo.closing);
         }
 
         self.gecko.mQuotes.set_move(refptr.get())
@@ -4206,14 +4206,14 @@ fn static_assert() {
     pub fn clone_quotes(&self) -> longhands::quotes::computed_value::T {
         unsafe {
             let ref gecko_quote_values = *self.gecko.mQuotes.mRawPtr;
-            longhands::quotes::computed_value::T(
+            longhands::quotes::computed_value::T(Arc::new(
                 gecko_quote_values.mQuotePairs.iter().map(|gecko_pair| {
-                    (
-                        gecko_pair.first.to_string().into_boxed_str(),
-                        gecko_pair.second.to_string().into_boxed_str(),
-                    )
+                    values::specified::QuotePair {
+                        opening: gecko_pair.first.to_string().into_boxed_str(),
+                        closing: gecko_pair.second.to_string().into_boxed_str(),
+                    }
                 }).collect::<Vec<_>>().into_boxed_slice()
-            )
+            ))
         }
     }
 

components/style/values/computed/list.rs

@@ -6,26 +6,30 @@
 
 #[cfg(feature = "gecko")]
 pub use values::specified::list::ListStyleType;
-pub use values::specified::list::Quotes;
+pub use values::specified::list::{QuotePair, Quotes};
+
+use servo_arc::Arc;
+use values::specified::list::QuotePair;
+
+lazy_static! {
+    static ref INITIAL_QUOTES: Arc<Box<[QuotePair]>> = Arc::new(
+        vec![
+            QuotePair {
+                opening: "\u{201c}".to_owned().into_boxed_str(),
+                closing: "\u{201d}".to_owned().into_boxed_str(),
+            },
+            QuotePair {
+                opening: "\u{2018}".to_owned().into_boxed_str(),
+                closing: "\u{2019}".to_owned().into_boxed_str(),
+            },
+        ].into_boxed_slice()
+    );
+}
 
 impl Quotes {
     /// Initial value for `quotes`.
-    ///
-    /// FIXME(emilio): This should ideally not allocate.
     #[inline]
     pub fn get_initial_value() -> Quotes {
-        Quotes(
-            vec![
-                (
-                    "\u{201c}".to_owned().into_boxed_str(),
-                    "\u{201d}".to_owned().into_boxed_str(),
-                ),
-                (
-                    "\u{2018}".to_owned().into_boxed_str(),
-                    "\u{2019}".to_owned().into_boxed_str(),
-                ),
-            ]
-            .into_boxed_slice(),
-        )
+        Quotes(INITIAL_QUOTES.clone())
     }
 }

components/style/values/computed/mod.rs

@@ -69,7 +69,7 @@ pub use self::length::{LengthOrPercentageOrAuto, LengthOrPercentageOrNone, MaxLe
 pub use self::length::{NonNegativeLengthOrPercentage, NonNegativeLengthOrPercentageOrAuto};
 #[cfg(feature = "gecko")]
 pub use self::list::ListStyleType;
-pub use self::list::Quotes;
+pub use self::list::{QuotePair, Quotes};
 pub use self::motion::OffsetPath;
 pub use self::outline::OutlineStyle;
 pub use self::percentage::{NonNegativePercentage, Percentage};

components/style/values/specified/list.rs

@@ -6,8 +6,8 @@
 
 use cssparser::{Parser, Token};
 use parser::{Parse, ParserContext};
-use std::fmt::{self, Write};
-use style_traits::{CssWriter, ParseError, StyleParseErrorKind, ToCss};
+use servo_arc::Arc;
+use style_traits::{ParseError, StyleParseErrorKind};
 #[cfg(feature = "gecko")]
 use values::generics::CounterStyleOrNone;
 #[cfg(feature = "gecko")]
@@ -73,41 +73,25 @@ impl Parse for ListStyleType {
     }
 }
 
-/// Specified and computed `quote` property.
-///
-/// FIXME(emilio): It's a shame that this allocates all the time it's computed,
-/// probably should just be refcounted.
-/// FIXME This can probably derive ToCss.
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToComputedValue)]
-pub struct Quotes(#[css(if_empty = "none")] pub Box<[(Box<str>, Box<str>)]>);
-
-impl ToCss for Quotes {
-    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
-    where
-        W: Write,
-    {
-        let mut iter = self.0.iter();
-
-        match iter.next() {
-            Some(&(ref l, ref r)) => {
-                l.to_css(dest)?;
-                dest.write_char(' ')?;
-                r.to_css(dest)?;
-            },
-            None => return dest.write_str("none"),
-        }
-
-        for &(ref l, ref r) in iter {
-            dest.write_char(' ')?;
-            l.to_css(dest)?;
-            dest.write_char(' ')?;
-            r.to_css(dest)?;
-        }
+/// A quote pair.
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToComputedValue, ToCss)]
+pub struct QuotePair {
+    /// The opening quote.
+    pub opening: Box<str>,
 
-        Ok(())
-    }
+    /// The closing quote.
+    pub closing: Box<str>,
 }
 
+/// Specified and computed `quotes` property.
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, SpecifiedValueInfo, ToComputedValue, ToCss)]
+pub struct Quotes(
+    #[css(if_empty = "none")]
+    #[css(iterable)]
+    #[ignore_malloc_size_of = "Arc"]
+    pub Arc<Box<[QuotePair]>>
+);
+
 impl Parse for Quotes {
     fn parse<'i, 't>(
         _: &ParserContext,
@@ -117,24 +101,24 @@ impl Parse for Quotes {
             .try(|input| input.expect_ident_matching("none"))
             .is_ok()
         {
-            return Ok(Quotes(Vec::new().into_boxed_slice()));
+            return Ok(Quotes(Arc::new(Box::new([]))));
         }
 
         let mut quotes = Vec::new();
         loop {
             let location = input.current_source_location();
-            let first = match input.next() {
+            let opening = match input.next() {
                 Ok(&Token::QuotedString(ref value)) => value.as_ref().to_owned().into_boxed_str(),
                 Ok(t) => return Err(location.new_unexpected_token_error(t.clone())),
                 Err(_) => break,
             };
 
-            let second = input.expect_string()?.as_ref().to_owned().into_boxed_str();
-            quotes.push((first, second))
+            let closing = input.expect_string()?.as_ref().to_owned().into_boxed_str();
+            quotes.push(QuotePair { opening, closing });
         }
 
         if !quotes.is_empty() {
-            Ok(Quotes(quotes.into_boxed_slice()))
+            Ok(Quotes(Arc::new(quotes.into_boxed_slice())))
         } else {
             Err(input.new_custom_error(StyleParseErrorKind::UnspecifiedError))
         }

components/style/values/specified/mod.rs

@@ -63,7 +63,7 @@ pub use self::length::{NoCalcLength, ViewportPercentageLength};
 pub use self::length::{NonNegativeLengthOrPercentage, NonNegativeLengthOrPercentageOrAuto};
 #[cfg(feature = "gecko")]
 pub use self::list::ListStyleType;
-pub use self::list::Quotes;
+pub use self::list::{QuotePair, Quotes};
 pub use self::motion::OffsetPath;
 pub use self::outline::OutlineStyle;
 pub use self::percentage::Percentage;