Auto merge of #12878 - Manishearth:clip-path, r=heycam

stylo: Support clip-path

Todo:

 - [x] `set_clip_path` (probably needs a bunch of gecko bindings for running constructors/destructors)
 - [ ] Ensure that I've ordered the coordinates correctly
 - [ ] Check that it works
 - [x] Might want to convert NS_STYLE_FILL_RULE and NS_RADIUS to enum classes

Depends on:

 - https://github.com/servo/rust-bindgen/pull/29
 - https://github.com/Manishearth/gecko-dev/compare/servo:stylo...Manishearth:clip-path

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components/style/values/specified/basic_shape.rs

@@ -8,13 +8,111 @@
 //! [basic-shape]: https://drafts.csswg.org/css-shapes/#typedef-basic-shape
 
 use cssparser::{Parser, ToCss};
+use parser::{ParserContext, Parse};
 use properties::shorthands::{parse_four_sides, serialize_four_sides};
 use std::fmt;
+use url::Url;
 use values::computed::basic_shape as computed_basic_shape;
 use values::computed::{Context, ToComputedValue, ComputedValueAsSpecified};
+use values::specified::UrlExtraData;
 use values::specified::position::Position;
 use values::specified::{BorderRadiusSize, LengthOrPercentage, Percentage};
 
+/// A shape source, for some reference box
+///
+/// clip-path uses ShapeSource<GeometryBox>,
+/// shape-outside uses ShapeSource<ShapeBox>
+#[derive(Clone, PartialEq, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum ShapeSource<T> {
+    Url(Url, UrlExtraData),
+    Shape(BasicShape, Option<T>),
+    Box(T),
+    None,
+}
+
+impl<T> Default for ShapeSource<T> {
+    fn default() -> Self {
+        ShapeSource::None
+    }
+}
+
+impl<T: ToCss> ToCss for ShapeSource<T> {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        use values::LocalToCss;
+        match *self {
+            ShapeSource::Url(ref url, _) => url.to_css(dest),
+            ShapeSource::Shape(ref shape, Some(ref reference)) => {
+                try!(shape.to_css(dest));
+                try!(dest.write_str(" "));
+                reference.to_css(dest)
+            }
+            ShapeSource::Shape(ref shape, None) => shape.to_css(dest),
+            ShapeSource::Box(ref reference) => reference.to_css(dest),
+            ShapeSource::None => dest.write_str("none"),
+
+        }
+    }
+}
+
+impl<T: Parse + PartialEq + Copy> ShapeSource<T> {
+    pub fn parse(context: &ParserContext, input: &mut Parser) -> Result<Self, ()> {
+        if let Ok(_) = input.try(|input| input.expect_ident_matching("none")) {
+            Ok(ShapeSource::None)
+        } else if let Ok(url) = input.try(|input| input.expect_url()) {
+            match UrlExtraData::make_from(context) {
+                Some(extra_data) => {
+                    Ok(ShapeSource::Url(context.parse_url(&url), extra_data))
+                },
+                None => Err(()),
+            }
+        } else {
+            fn parse_component<U: Parse>(input: &mut Parser, component: &mut Option<U>) -> bool {
+                if component.is_some() {
+                    return false; // already parsed this component
+                }
+                *component = input.try(U::parse).ok();
+                component.is_some()
+            }
+
+            let mut shape = None;
+            let mut reference = None;
+            loop {
+                if !parse_component(input, &mut shape) &&
+                   !parse_component(input, &mut reference) {
+                    break;
+                }
+            }
+            match (shape, reference) {
+                (Some(shape), _) => Ok(ShapeSource::Shape(shape, reference)),
+                (None, Some(reference)) => Ok(ShapeSource::Box(reference)),
+                (None, None) => Err(()),
+            }
+        }
+    }
+}
+
+impl<T: ToComputedValue> ToComputedValue for ShapeSource<T> {
+    type ComputedValue = computed_basic_shape::ShapeSource<T::ComputedValue>;
+    #[inline]
+    fn to_computed_value(&self, cx: &Context) -> Self::ComputedValue {
+        match *self {
+            ShapeSource::Url(ref url, ref data) => {
+                computed_basic_shape::ShapeSource::Url(url.clone(), data.clone())
+            }
+            ShapeSource::Shape(ref shape, ref reference) => {
+                computed_basic_shape::ShapeSource::Shape(
+                    shape.to_computed_value(cx),
+                    reference.as_ref().map(|ref r| r.to_computed_value(cx)))
+            }
+            ShapeSource::Box(ref reference) => {
+                computed_basic_shape::ShapeSource::Box(reference.to_computed_value(cx))
+            }
+            ShapeSource::None => computed_basic_shape::ShapeSource::None,
+        }
+    }
+}
+
 #[derive(Clone, PartialEq, Debug)]
 #[cfg_attr(feature = "servo", derive(HeapSizeOf))]
 pub enum BasicShape {
@@ -24,8 +122,8 @@ pub enum BasicShape {
     Polygon(Polygon),
 }
 
-impl BasicShape {
-    pub fn parse(input: &mut Parser) -> Result<BasicShape, ()> {
+impl Parse for BasicShape {
+    fn parse(input: &mut Parser) -> Result<BasicShape, ()> {
         match_ignore_ascii_case! { try!(input.expect_function()),
             "inset" => {
                 Ok(BasicShape::Inset(
@@ -528,3 +626,77 @@ impl ToCss for FillRule {
         }
     }
 }
+
+/// https://drafts.fxtf.org/css-masking-1/#typedef-geometry-box
+#[derive(Clone, PartialEq, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum GeometryBox {
+    Fill,
+    Stroke,
+    View,
+    ShapeBox(ShapeBox),
+}
+
+impl Parse for GeometryBox {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        if let Ok(shape_box) = input.try(ShapeBox::parse) {
+            Ok(GeometryBox::ShapeBox(shape_box))
+        } else {
+            match_ignore_ascii_case! { try!(input.expect_ident()),
+                "fill-box" => Ok(GeometryBox::Fill),
+                "stroke-box" => Ok(GeometryBox::Stroke),
+                "view-box" => Ok(GeometryBox::View),
+                _ => Err(())
+            }
+        }
+    }
+}
+
+impl ToCss for GeometryBox {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            GeometryBox::Fill => dest.write_str("fill-box"),
+            GeometryBox::Stroke => dest.write_str("stroke-box"),
+            GeometryBox::View => dest.write_str("view-box"),
+            GeometryBox::ShapeBox(s) => s.to_css(dest),
+        }
+    }
+}
+
+impl ComputedValueAsSpecified for GeometryBox {}
+
+// https://drafts.csswg.org/css-shapes-1/#typedef-shape-box
+#[derive(Clone, PartialEq, Copy, Debug)]
+#[cfg_attr(feature = "servo", derive(HeapSizeOf))]
+pub enum ShapeBox {
+    Margin,
+    // https://drafts.csswg.org/css-backgrounds-3/#box
+    Border,
+    Padding,
+    Content,
+}
+
+impl Parse for ShapeBox {
+    fn parse(input: &mut Parser) -> Result<Self, ()> {
+        match_ignore_ascii_case! { try!(input.expect_ident()),
+            "margin-box" => Ok(ShapeBox::Margin),
+            "border-box" => Ok(ShapeBox::Border),
+            "padding-box" => Ok(ShapeBox::Padding),
+            "content-box" => Ok(ShapeBox::Content),
+            _ => Err(())
+        }
+    }
+}
+
+impl ToCss for ShapeBox {
+    fn to_css<W>(&self, dest: &mut W) -> fmt::Result where W: fmt::Write {
+        match *self {
+            ShapeBox::Margin => dest.write_str("margin-box"),
+            ShapeBox::Border => dest.write_str("border-box"),
+            ShapeBox::Padding => dest.write_str("padding-box"),
+            ShapeBox::Content => dest.write_str("content-box"),
+        }
+    }
+}
+
+impl ComputedValueAsSpecified for ShapeBox {}