Auto merge of #17058 - Manishearth:stylo-randomprops, r=emilio

stylo: Support remaning longhands

r=xidorn https://bugzilla.mozilla.org/show_bug.cgi?id=1367275

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components/style/values/generics/mod.rs

@@ -10,7 +10,7 @@ use cssparser::Parser;
 use euclid::size::Size2D;
 use parser::{Parse, ParserContext};
 use std::fmt;
-use style_traits::{HasViewportPercentage, ToCss};
+use style_traits::{HasViewportPercentage, OneOrMoreCommaSeparated, ToCss};
 use super::CustomIdent;
 
 pub use self::basic_shape::serialize_radius_values;
@@ -163,3 +163,152 @@ impl ToCss for CounterStyleOrNone {
         }
     }
 }
+
+/// A settings tag, defined by a four-character tag and a setting value
+///
+/// For font-feature-settings, this is a tag and an integer,
+/// for font-variation-settings this is a tag and a float
+#[derive(Clone, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct FontSettingTag<T> {
+    /// A four-character tag, packed into a u32 (one byte per character)
+    pub tag: u32,
+    /// The value
+    pub value: T,
+}
+
+impl<T> OneOrMoreCommaSeparated for FontSettingTag<T> {}
+
+impl<T: ToCss> ToCss for FontSettingTag<T> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use byteorder::{WriteBytesExt, BigEndian};
+        use cssparser::serialize_string;
+        use std::str;
+
+        let mut raw: Vec<u8> = vec!();
+        raw.write_u32::<BigEndian>(self.tag).unwrap();
+        serialize_string(str::from_utf8(&raw).unwrap_or_default(), dest)?;
+
+        self.value.to_css(dest)
+    }
+}
+
+impl<T: Parse> Parse for FontSettingTag<T> {
+    /// https://www.w3.org/TR/css-fonts-3/#propdef-font-feature-settings
+    /// https://drafts.csswg.org/css-fonts-4/#low-level-font-variation-
+    /// settings-control-the-font-variation-settings-property
+    /// <string> [ on | off | <integer> ]
+    /// <string> <number>
+    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        use byteorder::{ReadBytesExt, BigEndian};
+        use std::io::Cursor;
+
+        let tag = try!(input.expect_string());
+
+        // allowed strings of length 4 containing chars: <U+20, U+7E>
+        if tag.len() != 4 ||
+           tag.chars().any(|c| c < ' ' || c > '~')
+        {
+            return Err(())
+        }
+
+        let mut raw = Cursor::new(tag.as_bytes());
+        let u_tag = raw.read_u32::<BigEndian>().unwrap();
+
+        Ok(FontSettingTag { tag: u_tag, value: T::parse(context, input)? })
+    }
+}
+
+
+/// A font settings value for font-variation-settings or font-feature-settings
+#[derive(Clone, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum FontSettings<T> {
+    /// No settings (default)
+    Normal,
+    /// Set of settings
+    Tag(Vec<FontSettingTag<T>>)
+}
+
+impl<T: ToCss> ToCss for FontSettings<T> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            FontSettings::Normal => dest.write_str("normal"),
+            FontSettings::Tag(ref ftvs) => ftvs.to_css(dest)
+        }
+    }
+}
+
+impl<T: Parse> Parse for FontSettings<T> {
+    /// https://www.w3.org/TR/css-fonts-3/#propdef-font-feature-settings
+    fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        if input.try(|i| i.expect_ident_matching("normal")).is_ok() {
+            return Ok(FontSettings::Normal);
+        }
+        Vec::parse(context, input).map(FontSettings::Tag)
+    }
+}
+
+/// An integer that can also parse "on" and "off",
+/// for font-feature-settings
+///
+/// Do not use this type anywhere except within FontSettings
+/// because it serializes with the preceding space
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct FontSettingTagInt(pub u32);
+/// A number value to be used for font-variation-settings
+///
+/// Do not use this type anywhere except within FontSettings
+/// because it serializes with the preceding space
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub struct FontSettingTagFloat(pub f32);
+
+impl ToCss for FontSettingTagInt {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match self.0 {
+            1 => Ok(()),
+            0 => dest.write_str(" off"),
+            x => write!(dest, " {}", x)
+        }
+    }
+}
+
+impl Parse for FontSettingTagInt {
+    fn parse(_context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        if let Ok(value) = input.try(|input| input.expect_integer()) {
+            // handle integer, throw if it is negative
+            if value >= 0 {
+                Ok(FontSettingTagInt(value as u32))
+            } else {
+                Err(())
+            }
+        } else if let Ok(_) = input.try(|input| input.expect_ident_matching("on")) {
+            // on is an alias for '1'
+            Ok(FontSettingTagInt(1))
+        } else if let Ok(_) = input.try(|input| input.expect_ident_matching("off")) {
+            // off is an alias for '0'
+            Ok(FontSettingTagInt(0))
+        } else {
+            // empty value is an alias for '1'
+            Ok(FontSettingTagInt(1))
+        }
+    }
+}
+
+
+impl Parse for FontSettingTagFloat {
+    fn parse(_: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        input.expect_number().map(FontSettingTagFloat)
+    }
+}
+
+impl ToCss for FontSettingTagFloat {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        dest.write_str(" ")?;
+        self.0.to_css(dest)
+    }
+}
+
+