Make it possible to build the style_traits crate with a stable compiler.

Testing this on CI to make sure we don’t regress it is blocked on #11806

components/style_traits/Cargo.toml

@@ -8,13 +8,16 @@ publish = false
 name = "style_traits"
 path = "lib.rs"
 
+[features]
+heap_size = ["heapsize", "heapsize_plugin", "cssparser/heap_size", "euclid/plugins"]
+serde-serialization = ["serde", "serde_macros", "cssparser/serde-serialization", "euclid/plugins"]
+
 [dependencies]
 util = {path = "../util"}
-plugins = {path = "../plugins"}
-cssparser = {version = "0.5.4", features = ["heap_size", "serde-serialization"]}
-euclid = {version = "0.6.4", features = ["plugins"]}
-heapsize = "0.3.0"
-heapsize_plugin = "0.1.2"
+cssparser = "0.5.4"
+euclid = "0.6.4"
+heapsize = {version = "0.3.0", optional = true}
+heapsize_plugin = {version = "0.1.2", optional = true}
 rustc-serialize = "0.3"
-serde = "0.7"
-serde_macros = "0.7"
+serde = {version = "0.7", optional = true}
+serde_macros = {version = "0.7", optional = true}

components/style_traits/cursor.rs

@@ -8,7 +8,9 @@ use cssparser::ToCss;
 
 macro_rules! define_cursor {
     ($( $css: expr => $variant: ident = $value: expr, )+) => {
-        #[derive(Clone, Copy, Debug, Deserialize, Eq, HeapSizeOf, PartialEq, Serialize)]
+        #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+        #[cfg_attr(feature = "serde-serialization", derive(Deserialize, Serialize))]
+        #[cfg_attr(feature = "heap_size", derive(HeapSizeOf))]
         #[repr(u8)]
         pub enum Cursor {
             $( $variant = $value ),+

components/style_traits/lib.rs

@@ -8,19 +8,22 @@
 
 #![crate_name = "style_traits"]
 #![crate_type = "rlib"]
-#![feature(custom_derive)]
-#![feature(plugin)]
-#![plugin(heapsize_plugin)]
-#![plugin(serde_macros)]
-#![plugin(plugins)]
+
 #![deny(unsafe_code)]
 
+#![cfg_attr(feature = "serde-serialization", feature(custom_derive))]
+#![cfg_attr(feature = "serde-serialization", feature(plugin))]
+#![cfg_attr(feature = "serde-serialization", plugin(serde_macros))]
+#![cfg_attr(feature = "heap_size", feature(custom_derive))]
+#![cfg_attr(feature = "heap_size", feature(plugin))]
+#![cfg_attr(feature = "heap_size", plugin(heapsize_plugin))]
+
 #[macro_use]
 extern crate cssparser;
 extern crate euclid;
-extern crate heapsize;
+#[cfg(feature = "heap_size")] extern crate heapsize;
 extern crate rustc_serialize;
-extern crate serde;
+#[cfg(feature = "serde-serialization")] extern crate serde;
 extern crate util;
 
 pub mod cursor;

components/style_traits/values.rs

@@ -5,12 +5,58 @@
 #[macro_export]
 macro_rules! define_css_keyword_enum {
     ($name: ident: $( $css: expr => $variant: ident ),+,) => {
-        define_css_keyword_enum!($name: $( $css => $variant ),+);
+        __define_css_keyword_enum__add_serde!($name [ $( $css => $variant ),+ ]);
     };
     ($name: ident: $( $css: expr => $variant: ident ),+) => {
+        __define_css_keyword_enum__add_serde!($name [ $( $css => $variant ),+ ]);
+    };
+}
+
+#[cfg(feature = "serde-serialization")]
+#[macro_export]
+macro_rules! __define_css_keyword_enum__add_serde {
+    ($name: ident [ $( $css: expr => $variant: ident ),+ ]) => {
+        __define_css_keyword_enum__add_heapsize! {
+            $name [ Deserialize, Serialize ] [ $( $css => $variant ),+ ]
+        }
+    };
+}
+
+#[cfg(not(feature = "serde-serialization"))]
+#[macro_export]
+macro_rules! __define_css_keyword_enum__add_serde {
+    ($name: ident [ $( $css: expr => $variant: ident ),+ ]) => {
+        __define_css_keyword_enum__add_heapsize! {
+            $name [] [ $( $css => $variant ),+ ]
+        }
+    };
+}
+
+#[cfg(feature = "heap_size")]
+#[macro_export]
+macro_rules! __define_css_keyword_enum__add_heapsize {
+    ($name: ident [ $( $derived_trait: ident),* ]  [ $( $css: expr => $variant: ident ),+ ]) => {
+        __define_css_keyword_enum__actual! {
+            $name [  $( $derived_trait, )* HeapSizeOf ] [ $( $css => $variant ),+ ]
+        }
+    };
+}
+
+#[cfg(not(feature = "heap_size"))]
+#[macro_export]
+macro_rules! __define_css_keyword_enum__add_heapsize {
+    ($name: ident [ $( $derived_trait: ident),* ]  [ $( $css: expr => $variant: ident ),+ ]) => {
+        __define_css_keyword_enum__actual! {
+            $name [ $( $derived_trait ),* ] [ $( $css => $variant ),+ ]
+        }
+    };
+}
+
+#[macro_export]
+macro_rules! __define_css_keyword_enum__actual {
+    ($name: ident [ $( $derived_trait: ident),* ] [ $( $css: expr => $variant: ident ),+ ]) => {
         #[allow(non_camel_case_types)]
-        #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug, HeapSizeOf)]
-        #[derive(Deserialize, Serialize)]
+        #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug $(, $derived_trait )* )]
         pub enum $name {
             $( $variant ),+
         }

components/style_traits/viewport.rs

@@ -20,7 +20,9 @@ define_css_keyword_enum!(Orientation:
                          "landscape" => Landscape);
 
 
-#[derive(Clone, Debug, PartialEq, Deserialize, Serialize, HeapSizeOf)]
+#[derive(Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "serde-serialization", derive(Deserialize, Serialize))]
+#[cfg_attr(feature = "heap_size", derive(HeapSizeOf))]
 pub struct ViewportConstraints {
     pub size: TypedSize2D<ViewportPx, f32>,
 
@@ -54,7 +56,8 @@ impl ToCss for ViewportConstraints {
 
 /// Zoom is a number | percentage | auto
 /// See http://dev.w3.org/csswg/css-device-adapt/#descdef-viewport-zoom
-#[derive(Copy, Clone, Debug, HeapSizeOf, PartialEq)]
+#[derive(Copy, Clone, Debug, PartialEq)]
+#[cfg_attr(feature = "heap_size", derive(HeapSizeOf))]
 pub enum Zoom {
     Number(f32),
     Percentage(f32),