Derive ToCss for TransformOperation

Now that SequenceWriter<W> does not monomorphise excessively, we can actually
type check a derived ToCss without too much type recursion.

components/style/values/generics/transform.rs

@@ -30,7 +30,8 @@ pub struct Matrix<T, U = T> {
 
 #[allow(missing_docs)]
 #[cfg_attr(rustfmt, rustfmt_skip)]
-#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[css(comma, function = "matrix3d")]
+#[derive(Clone, Copy, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 pub struct Matrix3D<T, U = T, V = T> {
     pub m11: T, pub m12: T, pub m13: T, pub m14: T,
     pub m21: T, pub m22: T, pub m23: T, pub m24: T,
@@ -191,7 +192,7 @@ impl TimingKeyword {
     }
 }
 
-#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue)]
+#[derive(Clone, Debug, MallocSizeOf, PartialEq, ToComputedValue, ToCss)]
 /// A single operation in the list of a `transform` value
 pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, LengthOrPercentage, LoPoNumber> {
     /// Represents a 2D 2x3 matrix.
@@ -200,31 +201,37 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
     /// For `moz-transform`.
     PrefixedMatrix(Matrix<Number, LoPoNumber>),
     /// Represents a 3D 4x4 matrix.
-    #[allow(missing_docs)]
     Matrix3D(Matrix3D<Number>),
     /// Represents a 3D 4x4 matrix with percentage and length values.
     /// For `moz-transform`.
-    #[allow(missing_docs)]
     PrefixedMatrix3D(Matrix3D<Number, LoPoNumber, LengthOrNumber>),
     /// A 2D skew.
     ///
     /// If the second angle is not provided it is assumed zero.
     ///
     /// Syntax can be skew(angle) or skew(angle, angle)
+    #[css(comma, function)]
     Skew(Angle, Option<Angle>),
     /// skewX(angle)
+    #[css(function = "skewX")]
     SkewX(Angle),
     /// skewY(angle)
+    #[css(function = "skewY")]
     SkewY(Angle),
     /// translate(x, y) or translate(x)
+    #[css(comma, function)]
     Translate(LengthOrPercentage, Option<LengthOrPercentage>),
     /// translateX(x)
+    #[css(function = "translateX")]
     TranslateX(LengthOrPercentage),
     /// translateY(y)
+    #[css(function = "translateY")]
     TranslateY(LengthOrPercentage),
     /// translateZ(z)
+    #[css(function = "translateZ")]
     TranslateZ(Length),
     /// translate3d(x, y, z)
+    #[css(comma, function = "translate3d")]
     Translate3D(LengthOrPercentage, LengthOrPercentage, Length),
     /// A 2D scaling factor.
     ///
@@ -234,28 +241,38 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
     /// Negative values are allowed and flip the element.
     ///
     /// Syntax can be scale(factor) or scale(factor, factor)
+    #[css(comma, function)]
     Scale(Number, Option<Number>),
     /// scaleX(factor)
+    #[css(function = "scaleX")]
     ScaleX(Number),
     /// scaleY(factor)
+    #[css(function = "scaleY")]
     ScaleY(Number),
     /// scaleZ(factor)
+    #[css(function = "scaleZ")]
     ScaleZ(Number),
     /// scale3D(factorX, factorY, factorZ)
+    #[css(comma, function = "scale3d")]
     Scale3D(Number, Number, Number),
     /// Describes a 2D Rotation.
     ///
     /// In a 3D scene `rotate(angle)` is equivalent to `rotateZ(angle)`.
+    #[css(function)]
     Rotate(Angle),
     /// Rotation in 3D space around the x-axis.
+    #[css(function = "rotateX")]
     RotateX(Angle),
     /// Rotation in 3D space around the y-axis.
+    #[css(function = "rotateY")]
     RotateY(Angle),
     /// Rotation in 3D space around the z-axis.
+    #[css(function = "rotateZ")]
     RotateZ(Angle),
     /// Rotation in 3D space.
     ///
     /// Generalization of rotateX, rotateY and rotateZ.
+    #[css(comma, function = "rotate3d")]
     Rotate3D(Number, Number, Number, Angle),
     /// Specifies a perspective projection matrix.
     ///
@@ -263,11 +280,14 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
     /// [§ 13.1. 3D Transform Function](https://drafts.csswg.org/css-transforms-2/#funcdef-perspective).
     ///
     /// The value must be greater than or equal to zero.
+    #[css(function)]
     Perspective(Length),
     /// A intermediate type for interpolation of mismatched transform lists.
     #[allow(missing_docs)]
+    #[css(comma, function = "interpolatematrix")]
     InterpolateMatrix {
         #[compute(ignore_bound)]
+        #[css(ignore_bound)]
         from_list: Transform<
             TransformOperation<
                 Angle,
@@ -280,6 +300,7 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
             >,
         >,
         #[compute(ignore_bound)]
+        #[css(ignore_bound)]
         to_list: Transform<
             TransformOperation<
                 Angle,
@@ -296,8 +317,10 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
     },
     /// A intermediate type for accumulation of mismatched transform lists.
     #[allow(missing_docs)]
+    #[css(comma, function = "accumulatematrix")]
     AccumulateMatrix {
         #[compute(ignore_bound)]
+        #[css(ignore_bound)]
         from_list: Transform<
             TransformOperation<
                 Angle,
@@ -310,6 +333,7 @@ pub enum TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, Leng
             >,
         >,
         #[compute(ignore_bound)]
+        #[css(ignore_bound)]
         to_list: Transform<
             TransformOperation<
                 Angle,
@@ -541,120 +565,6 @@ where
     }
 }
 
-#[cfg_attr(rustfmt, rustfmt_skip)]
-impl<Angle: ToCss + Copy, Number: ToCss + Copy, Length: ToCss,
-     Integer: ToCss + Copy, LengthOrNumber: ToCss, LengthOrPercentage: ToCss, LoPoNumber: ToCss>
-    ToCss for
-    TransformOperation<Angle, Number, Length, Integer, LengthOrNumber, LengthOrPercentage, LoPoNumber> {
-    fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
-    where
-        W: Write,
-    {
-        match *self {
-            TransformOperation::Matrix(ref m) => m.to_css(dest),
-            TransformOperation::PrefixedMatrix(ref m) => m.to_css(dest),
-            TransformOperation::Matrix3D(Matrix3D {
-                m11, m12, m13, m14,
-                m21, m22, m23, m24,
-                m31, m32, m33, m34,
-                m41, m42, m43, m44,
-            }) => {
-                serialize_function!(dest, matrix3d(
-                    m11, m12, m13, m14,
-                    m21, m22, m23, m24,
-                    m31, m32, m33, m34,
-                    m41, m42, m43, m44,
-                ))
-            }
-            TransformOperation::PrefixedMatrix3D(Matrix3D {
-                m11, m12, m13, m14,
-                m21, m22, m23, m24,
-                m31, m32, m33, m34,
-                ref m41, ref m42, ref m43, m44,
-            }) => {
-                serialize_function!(dest, matrix3d(
-                    m11, m12, m13, m14,
-                    m21, m22, m23, m24,
-                    m31, m32, m33, m34,
-                    m41, m42, m43, m44,
-                ))
-            }
-            TransformOperation::Skew(ax, None) => {
-                serialize_function!(dest, skew(ax))
-            }
-            TransformOperation::Skew(ax, Some(ay)) => {
-                serialize_function!(dest, skew(ax, ay))
-            }
-            TransformOperation::SkewX(angle) => {
-                serialize_function!(dest, skewX(angle))
-            }
-            TransformOperation::SkewY(angle) => {
-                serialize_function!(dest, skewY(angle))
-            }
-            TransformOperation::Translate(ref tx, None) => {
-                serialize_function!(dest, translate(tx))
-            }
-            TransformOperation::Translate(ref tx, Some(ref ty)) => {
-                serialize_function!(dest, translate(tx, ty))
-            }
-            TransformOperation::TranslateX(ref tx) => {
-                serialize_function!(dest, translateX(tx))
-            }
-            TransformOperation::TranslateY(ref ty) => {
-                serialize_function!(dest, translateY(ty))
-            }
-            TransformOperation::TranslateZ(ref tz) => {
-                serialize_function!(dest, translateZ(tz))
-            }
-            TransformOperation::Translate3D(ref tx, ref ty, ref tz) => {
-                serialize_function!(dest, translate3d(tx, ty, tz))
-            }
-            TransformOperation::Scale(factor, None) => {
-                serialize_function!(dest, scale(factor))
-            }
-            TransformOperation::Scale(sx, Some(sy)) => {
-                serialize_function!(dest, scale(sx, sy))
-            }
-            TransformOperation::ScaleX(sx) => {
-                serialize_function!(dest, scaleX(sx))
-            }
-            TransformOperation::ScaleY(sy) => {
-                serialize_function!(dest, scaleY(sy))
-            }
-            TransformOperation::ScaleZ(sz) => {
-                serialize_function!(dest, scaleZ(sz))
-            }
-            TransformOperation::Scale3D(sx, sy, sz) => {
-                serialize_function!(dest, scale3d(sx, sy, sz))
-            }
-            TransformOperation::Rotate(theta) => {
-                serialize_function!(dest, rotate(theta))
-            }
-            TransformOperation::RotateX(theta) => {
-                serialize_function!(dest, rotateX(theta))
-            }
-            TransformOperation::RotateY(theta) => {
-                serialize_function!(dest, rotateY(theta))
-            }
-            TransformOperation::RotateZ(theta) => {
-                serialize_function!(dest, rotateZ(theta))
-            }
-            TransformOperation::Rotate3D(x, y, z, theta) => {
-                serialize_function!(dest, rotate3d(x, y, z, theta))
-            }
-            TransformOperation::Perspective(ref length) => {
-                serialize_function!(dest, perspective(length))
-            }
-            TransformOperation::InterpolateMatrix { ref from_list, ref to_list, progress } => {
-                serialize_function!(dest, interpolatematrix(from_list, to_list, progress))
-            }
-            TransformOperation::AccumulateMatrix { ref from_list, ref to_list, count } => {
-                serialize_function!(dest, accumulatematrix(from_list, to_list, count))
-            }
-        }
-    }
-}
-
 impl<T: ToCss> ToCss for Transform<T> {
     fn to_css<W>(&self, dest: &mut CssWriter<W>) -> fmt::Result
     where

components/style_derive/to_css.rs

@@ -3,8 +3,9 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use cg;
+use darling::{Error, FromMetaItem};
 use quote::Tokens;
-use syn::DeriveInput;
+use syn::{self, DeriveInput, Ident};
 use synstructure;
 
 pub fn derive(input: DeriveInput) -> Tokens {
@@ -16,13 +17,13 @@ pub fn derive(input: DeriveInput) -> Tokens {
     let input_attrs = cg::parse_input_attrs::<CssInputAttrs>(&input);
     let style = synstructure::BindStyle::Ref.into();
     let match_body = synstructure::each_variant(&input, &style, |bindings, variant| {
-        let mut identifier = cg::to_css_identifier(variant.ident.as_ref());
+        let identifier = cg::to_css_identifier(variant.ident.as_ref());
         let variant_attrs = cg::parse_variant_attrs::<CssVariantAttrs>(variant);
         let separator = if variant_attrs.comma { ", " } else { " " };
 
         if variant_attrs.dimension {
             assert_eq!(bindings.len(), 1);
-            assert!(!variant_attrs.function, "That makes no sense");
+            assert!(variant_attrs.function.is_none(), "That makes no sense");
         }
 
         let mut expr = if !bindings.is_empty() {
@@ -39,7 +40,10 @@ pub fn derive(input: DeriveInput) -> Tokens {
                 };
             } else {
                 for binding in bindings {
+                    let attrs = cg::parse_field_attrs::<CssFieldAttrs>(&binding.field);
+                    if !attrs.ignore_bound {
                         where_clause.add_trait_bound(&binding.field.ty);
+                    }
                     expr = quote! {
                         #expr
                         writer.item(#binding)?;
@@ -63,7 +67,8 @@ pub fn derive(input: DeriveInput) -> Tokens {
                 #expr?;
                 ::std::fmt::Write::write_str(dest, #identifier)
             }
-        } else if variant_attrs.function {
+        } else if let Some(function) = variant_attrs.function {
+            let mut identifier = function.name.map_or(identifier, |name| name.to_string());
             identifier.push_str("(");
             expr = quote! {
                 ::std::fmt::Write::write_str(dest, #identifier)?;
@@ -112,15 +117,36 @@ pub fn derive(input: DeriveInput) -> Tokens {
 #[derive(Default, FromDeriveInput)]
 struct CssInputAttrs {
     derive_debug: bool,
-    function: bool,
+    function: Option<Function>,
     comma: bool,
 }
 
 #[darling(attributes(css), default)]
 #[derive(Default, FromVariant)]
 struct CssVariantAttrs {
-    function: bool,
+    function: Option<Function>,
     iterable: bool,
     comma: bool,
     dimension: bool,
 }
+
+#[darling(attributes(css), default)]
+#[derive(Default, FromField)]
+struct CssFieldAttrs {
+    ignore_bound: bool,
+}
+
+struct Function {
+    name: Option<Ident>,
+}
+
+impl FromMetaItem for Function {
+    fn from_word() -> Result<Self, Error> {
+        Ok(Self { name: None })
+    }
+
+    fn from_string(name: &str) -> Result<Self, Error> {
+        let name = syn::parse_ident(name).map_err(Error::custom)?;
+        Ok(Self { name: Some(name) })
+    }
+}