Auto merge of #6188 - Manishearth:sizeof, r=nnethercote

Fixes #5914

r? @nnethercote for the gfx changes

r? @kmcallister or @jdm for the plugin

<!-- Reviewable:start -->
[<img src="https://reviewable.io/review_button.png" height=40 alt="Review on Reviewable"/>](https://reviewable.io/reviews/servo/servo/6188)
<!-- Reviewable:end -->

components/gfx/display_list/mod.rs

@@ -24,10 +24,10 @@ use text::glyph::CharIndex;
 use text::TextRun;
 
 use azure::azure::AzFloat;
-use azure::azure_hl::{Color};
+use azure::azure_hl::Color;
 
 use collections::linked_list::{self, LinkedList};
-use geom::{Matrix2D, Point2D, Rect, SideOffsets2D, Size2D, Matrix4};
+use geom::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D, Matrix4};
 use geom::approxeq::ApproxEq;
 use geom::num::Zero;
 use libc::uintptr_t;
@@ -66,7 +66,7 @@ const MIN_INDENTATION_LENGTH: usize = 4;
 /// Because the script task's GC does not trace layout, node data cannot be safely stored in layout
 /// data structures. Also, layout code tends to be faster when the DOM is not being accessed, for
 /// locality reasons. Using `OpaqueNode` enforces this invariant.
-#[derive(Clone, PartialEq, Copy, Debug)]
+#[derive(Clone, PartialEq, Copy, Debug, HeapSizeOf)]
 pub struct OpaqueNode(pub uintptr_t);
 
 impl OpaqueNode {
@@ -82,6 +82,7 @@ impl OpaqueNode {
 ///
 /// TODO(pcwalton): We could reduce the size of this structure with a more "skip list"-like
 /// structure, omitting several pointers and lengths.
+#[derive(HeapSizeOf)]
 pub struct DisplayList {
     /// The border and backgrounds for the root of this stacking context: steps 1 and 2.
     pub background_and_borders: LinkedList<DisplayItem>,
@@ -218,24 +219,14 @@ impl DisplayList {
     }
 }
 
-impl HeapSizeOf for DisplayList {
-    fn heap_size_of_children(&self) -> usize {
-        self.background_and_borders.heap_size_of_children() +
-            self.block_backgrounds_and_borders.heap_size_of_children() +
-            self.floats.heap_size_of_children() +
-            self.content.heap_size_of_children() +
-            self.positioned_content.heap_size_of_children() +
-            self.outlines.heap_size_of_children() +
-            self.children.heap_size_of_children()
-    }
-}
-
+#[derive(HeapSizeOf)]
 /// Represents one CSS stacking context, which may or may not have a hardware layer.
 pub struct StackingContext {
     /// The display items that make up this stacking context.
     pub display_list: Box<DisplayList>,
 
     /// The layer for this stacking context, if there is one.
+    #[ignore_heap_size_of = "FIXME(njn): should measure this at some point"]
     pub layer: Option<Arc<PaintLayer>>,
 
     /// The position and size of this stacking context.
@@ -588,14 +579,6 @@ impl StackingContext {
     }
 }
 
-impl HeapSizeOf for StackingContext {
-    fn heap_size_of_children(&self) -> usize {
-        self.display_list.heap_size_of_children()
-
-        // FIXME(njn): other fields may be measured later, esp. `layer`
-    }
-}
-
 /// Returns the stacking context in the given tree of stacking contexts with a specific layer ID.
 pub fn find_stacking_context_with_layer_id(this: &Arc<StackingContext>, layer_id: LayerId)
                                            -> Option<Arc<StackingContext>> {
@@ -615,7 +598,7 @@ pub fn find_stacking_context_with_layer_id(this: &Arc<StackingContext>, layer_id
 }
 
 /// One drawing command in the list.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub enum DisplayItem {
     SolidColorClass(Box<SolidColorDisplayItem>),
     TextClass(Box<TextDisplayItem>),
@@ -627,7 +610,7 @@ pub enum DisplayItem {
 }
 
 /// Information common to all display items.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct BaseDisplayItem {
     /// The boundaries of the display item, in layer coordinates.
     pub bounds: Rect<Au>,
@@ -651,17 +634,11 @@ impl BaseDisplayItem {
     }
 }
 
-impl HeapSizeOf for BaseDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.metadata.heap_size_of_children() +
-            self.clip.heap_size_of_children()
-    }
-}
 
 /// A clipping region for a display item. Currently, this can describe rectangles, rounded
 /// rectangles (for `border-radius`), or arbitrary intersections of the two. Arbitrary transforms
 /// are not supported because those are handled by the higher-level `StackingContext` abstraction.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
 pub struct ClippingRegion {
     /// The main rectangular region. This does not include any corners.
     pub main: Rect<Au>,
@@ -675,7 +652,7 @@ pub struct ClippingRegion {
 /// A complex clipping region. These don't as easily admit arbitrary intersection operations, so
 /// they're stored in a list over to the side. Currently a complex clipping region is just a
 /// rounded rectangle, but the CSS WGs will probably make us throw more stuff in here eventually.
-#[derive(Clone, PartialEq, Debug)]
+#[derive(Clone, PartialEq, Debug, HeapSizeOf)]
 pub struct ComplexClippingRegion {
     /// The boundaries of the rectangle.
     pub rect: Rect<Au>,
@@ -783,22 +760,11 @@ impl ClippingRegion {
     }
 }
 
-impl HeapSizeOf for ClippingRegion {
-    fn heap_size_of_children(&self) -> usize {
-        self.complex.heap_size_of_children()
-    }
-}
-
-impl HeapSizeOf for ComplexClippingRegion {
-    fn heap_size_of_children(&self) -> usize {
-        0
-    }
-}
 
 /// Metadata attached to each display item. This is useful for performing auxiliary tasks with
 /// the display list involving hit testing: finding the originating DOM node and determining the
 /// cursor to use when the element is hovered over.
-#[derive(Clone, Copy)]
+#[derive(Clone, Copy, HeapSizeOf)]
 pub struct DisplayItemMetadata {
     /// The DOM node from which this display item originated.
     pub node: OpaqueNode,
@@ -826,14 +792,8 @@ impl DisplayItemMetadata {
     }
 }
 
-impl HeapSizeOf for DisplayItemMetadata {
-    fn heap_size_of_children(&self) -> usize {
-        0
-    }
-}
-
 /// Paints a solid color.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct SolidColorDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -842,19 +802,14 @@ pub struct SolidColorDisplayItem {
     pub color: Color,
 }
 
-impl HeapSizeOf for SolidColorDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-    }
-}
-
 /// Paints text.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct TextDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
 
     /// The text run.
+    #[ignore_heap_size_of = "Because it is non-owning"]
     pub text_run: Arc<Box<TextRun>>,
 
     /// The range of text within the text run.
@@ -873,14 +828,7 @@ pub struct TextDisplayItem {
     pub blur_radius: Au,
 }
 
-impl HeapSizeOf for TextDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-        // We exclude `text_run` because it is non-owning.
-    }
-}
-
-#[derive(Clone, Eq, PartialEq)]
+#[derive(Clone, Eq, PartialEq, HeapSizeOf)]
 pub enum TextOrientation {
     Upright,
     SidewaysLeft,
@@ -888,9 +836,10 @@ pub enum TextOrientation {
 }
 
 /// Paints an image.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct ImageDisplayItem {
     pub base: BaseDisplayItem,
+    #[ignore_heap_size_of = "Because it is non-owning"]
     pub image: Arc<Image>,
 
     /// The dimensions to which the image display item should be stretched. If this is smaller than
@@ -903,12 +852,6 @@ pub struct ImageDisplayItem {
     pub image_rendering: image_rendering::T,
 }
 
-impl HeapSizeOf for ImageDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-        // We exclude `image` here because it is non-owning.
-    }
-}
 
 /// Paints a gradient.
 #[derive(Clone)]
@@ -926,6 +869,7 @@ pub struct GradientDisplayItem {
     pub stops: Vec<GradientStop>,
 }
 
+
 impl HeapSizeOf for GradientDisplayItem {
     fn heap_size_of_children(&self) -> usize {
         use libc::c_void;
@@ -941,7 +885,7 @@ impl HeapSizeOf for GradientDisplayItem {
 
 
 /// Paints a border.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct BorderDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -961,16 +905,10 @@ pub struct BorderDisplayItem {
     pub radius: BorderRadii<Au>,
 }
 
-impl HeapSizeOf for BorderDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-    }
-}
-
 /// Information about the border radii.
 ///
 /// TODO(pcwalton): Elliptical radii.
-#[derive(Clone, Default, PartialEq, Debug, Copy)]
+#[derive(Clone, Default, PartialEq, Debug, Copy, HeapSizeOf)]
 pub struct BorderRadii<T> {
     pub top_left: T,
     pub top_right: T,
@@ -1000,7 +938,7 @@ impl<T> BorderRadii<T> where T: PartialEq + Zero + Clone {
 }
 
 /// Paints a line segment.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct LineDisplayItem {
     pub base: BaseDisplayItem,
 
@@ -1011,14 +949,8 @@ pub struct LineDisplayItem {
     pub style: border_style::T
 }
 
-impl HeapSizeOf for LineDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-    }
-}
-
 /// Paints a box shadow per CSS-BACKGROUNDS.
-#[derive(Clone)]
+#[derive(Clone, HeapSizeOf)]
 pub struct BoxShadowDisplayItem {
     /// Fields common to all display items.
     pub base: BaseDisplayItem,
@@ -1042,14 +974,8 @@ pub struct BoxShadowDisplayItem {
     pub clip_mode: BoxShadowClipMode,
 }
 
-impl HeapSizeOf for BoxShadowDisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        self.base.heap_size_of_children()
-    }
-}
-
 /// How a box shadow should be clipped.
-#[derive(Clone, Copy, Debug, PartialEq)]
+#[derive(Clone, Copy, Debug, PartialEq, HeapSizeOf)]
 pub enum BoxShadowClipMode {
     /// No special clipping should occur. This is used for (shadowed) text decorations.
     None,
@@ -1210,17 +1136,4 @@ impl fmt::Debug for DisplayItem {
     }
 }
 
-impl HeapSizeOf for DisplayItem {
-    fn heap_size_of_children(&self) -> usize {
-        match *self {
-            SolidColorClass(ref item) => item.heap_size_of_children(),
-            TextClass(ref item)       => item.heap_size_of_children(),
-            ImageClass(ref item)      => item.heap_size_of_children(),
-            BorderClass(ref item)     => item.heap_size_of_children(),
-            GradientClass(ref item)   => item.heap_size_of_children(),
-            LineClass(ref item)       => item.heap_size_of_children(),
-            BoxShadowClass(ref item)  => item.heap_size_of_children(),
-        }
-    }
-}
 

components/gfx/lib.rs

@@ -6,7 +6,8 @@
 #![feature(box_syntax)]
 #![feature(collections)]
 #![feature(core)]
-#![feature(plugin)]
+#![feature(plugin, custom_attribute)]
+#![feature(custom_derive)]
 #![feature(rustc_private)]
 #![feature(std_misc)]
 #![feature(str_char)]

components/gfx/text/glyph.rs

@@ -519,6 +519,7 @@ int_range_index! {
     #[derive(RustcEncodable)]
     #[doc = "An index that refers to a character in a text run. This could \
              point to the middle of a glyph."]
+    #[derive(HeapSizeOf)]
     struct CharIndex(isize)
 }
 

components/plugins/heap_size.rs

@@ -0,0 +1,81 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+//! Handles the auto-deriving for `#[derive(HeapSizeOf)]`
+//!
+//! This provides the `#[derive(HeapSizeOf)]` decorator, which
+//! generates a `HeapSizeOf` implementation that adds up
+//! calls to heap_size_of_children() for all the fields
+//! of a struct or enum variant.
+//!
+//! Fields marked `#[ignore_heap_size_of = "reason"]` will
+//! be ignored in this calculation. Providing a reason is compulsory.
+
+
+use syntax::ext::base::{Annotatable, ExtCtxt};
+use syntax::codemap::Span;
+use syntax::ptr::P;
+use syntax::ast::*;
+use syntax::attr::AttrMetaMethods;
+use syntax::ext::build::AstBuilder;
+use syntax::ext::deriving::generic::*;
+
+pub fn expand_heap_size(cx: &mut ExtCtxt, span: Span, mitem: &MetaItem,
+                        item: &Annotatable, push: &mut FnMut(Annotatable)) {
+    let trait_def = TraitDef {
+        span: span,
+        attributes: Vec::new(),
+        path: ty::Path::new(vec!("util", "mem", "HeapSizeOf")),
+        additional_bounds: Vec::new(),
+        generics: ty::LifetimeBounds::empty(),
+        methods: vec![
+            MethodDef {
+                name: "heap_size_of_children",
+                generics: ty::LifetimeBounds::empty(),
+                explicit_self: ty::borrowed_explicit_self(),
+                args: vec!(),
+                ret_ty: ty::Literal(ty::Path::new_local("usize")),
+                attributes: vec!(),
+                is_unsafe: false,
+                combine_substructure: combine_substructure(Box::new(heap_size_substructure))
+            }
+        ],
+        associated_types: vec![],
+    };
+    trait_def.expand(cx, mitem, item, push)
+}
+
+/// Defines how the implementation for `heap_size_of_children()` is to be generated.
+fn heap_size_substructure(cx: &mut ExtCtxt, trait_span: Span, substr: &Substructure) -> P<Expr> {
+    let fields = match *substr.fields {
+        Struct(ref fs) | EnumMatching(_, _, ref fs) => fs,
+        _ => cx.span_bug(trait_span, "impossible substructure in `#[derive(HeapSizeOf)]`")
+    };
+
+    fields.iter().fold(cx.expr_usize(trait_span, 0), |acc, ref item| {
+        if item.attrs.iter()
+               .find(|ref a| {
+                    if a.check_name("ignore_heap_size_of") {
+                        match a.node.value.node {
+                            MetaNameValue(..) => (),
+                            _ => cx.span_err(a.span, "#[ignore_heap_size_of] \
+                                                      should have an explanation, \
+                                                      e.g. #[ignore_heap_size_of = \"\"]")
+                        }
+                        true
+                    } else {
+                        false
+                    }
+                })
+               .is_some() {
+            acc
+        } else {
+            cx.expr_binary(item.span, BiAdd, acc,
+                           cx.expr_method_call(item.span,
+                                               item.self_.clone(),
+                                               substr.method_ident,
+                                               Vec::new()))
+                        }
+    })
+}

components/plugins/lib.rs

@@ -8,10 +8,10 @@
 //!
 //!  - `#[privatize]` : Forces all fields in a struct/enum to be private
 //!  - `#[jstraceable]` : Auto-derives an implementation of `JSTraceable` for a struct in the script crate
-//!  - `#[must_root]` : Prevents data of the marked type from being used on the stack. See the lints module for more
-//!     details
+//!  - `#[must_root]` : Prevents data of the marked type from being used on the stack.
+//!                     See the lints module for more details
 //!  - `#[dom_struct]` : Implies `#[privatize]`,`#[jstraceable]`, and `#[must_root]`.
-//!     Use this for structs that correspond to a DOM type
+//!                       Use this for structs that correspond to a DOM type
 
 #![feature(plugin_registrar, quote, plugin, box_syntax, rustc_private, collections)]
 
@@ -31,6 +31,8 @@ use syntax::parse::token::intern;
 // Public for documentation to show up
 /// Handles the auto-deriving for `#[jstraceable]`
 pub mod jstraceable;
+/// Handles the auto-deriving for `#[derive(HeapSizeOf)]`
+pub mod heap_size;
 /// Autogenerates implementations of Reflectable on DOM structs
 pub mod reflector;
 pub mod lints;
@@ -43,6 +45,7 @@ pub fn plugin_registrar(reg: &mut Registry) {
     reg.register_syntax_extension(intern("dom_struct"), MultiModifier(box jstraceable::expand_dom_struct));
     reg.register_syntax_extension(intern("jstraceable"), MultiDecorator(box jstraceable::expand_jstraceable));
     reg.register_syntax_extension(intern("_generate_reflector"), MultiDecorator(box reflector::expand_reflector));
+    reg.register_syntax_extension(intern("derive_HeapSizeOf"), MultiDecorator(box heap_size::expand_heap_size));
     reg.register_macro("to_lower", casing::expand_lower);
     reg.register_macro("to_upper", casing::expand_upper);
     reg.register_lint_pass(box lints::transmute_type::TransmutePass as LintPassObject);

components/servo/Cargo.lock

@@ -1280,6 +1280,7 @@ name = "util_tests"
 version = "0.0.1"
 dependencies = [
  "geom 0.1.0 (git+https://github.com/servo/rust-geom)",
+ "plugins 0.0.1",
  "util 0.0.1",
 ]
 

components/style/lib.rs

@@ -9,8 +9,9 @@
 #![feature(collections)]
 #![feature(hash)]
 #![feature(rustc_private)]
-
+#![feature(custom_attribute, custom_derive)]
 #![plugin(string_cache_plugin)]
+#![plugin(plugins)]
 
 #[macro_use] extern crate log;
 #[macro_use] extern crate bitflags;

components/style/properties.mako.rs

@@ -1027,8 +1027,8 @@ pub mod longhands {
         #[inline]
         pub fn get_initial_value() -> computed_value::T {
             computed_value::T(vec![
-                ("\u{201c}".to_string(), "\u{201d}".to_string()),
-                ("\u{2018}".to_string(), "\u{2019}".to_string()),
+                ("\u{201c}".to_owned(), "\u{201d}".to_owned()),
+                ("\u{2018}".to_owned(), "\u{2019}".to_owned()),
             ])
         }
 
@@ -2935,7 +2935,7 @@ pub mod longhands {
             use values::CSSFloat;
             use values::specified::{Angle};
 
-            #[derive(Clone, PartialEq, Debug)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
             pub enum Filter {
                 Blur(Au),
                 Brightness(CSSFloat),
@@ -2948,7 +2948,7 @@ pub mod longhands {
                 Sepia(CSSFloat),
             }
 
-            #[derive(Clone, PartialEq, Debug)]
+            #[derive(Clone, PartialEq, Debug, HeapSizeOf)]
             pub struct T { pub filters: Vec<Filter> }
 
             impl T {
@@ -3631,7 +3631,7 @@ pub mod longhands {
             use cssparser::ToCss;
             use std::fmt;
 
-            #[derive(Copy, Clone, Debug, PartialEq)]
+            #[derive(Copy, Clone, Debug, PartialEq, HeapSizeOf)]
             pub enum T {
                 Auto,
                 CrispEdges,

components/style/values.rs

@@ -12,7 +12,7 @@ macro_rules! define_css_keyword_enum {
     };
     ($name: ident: $( $css: expr => $variant: ident ),+) => {
         #[allow(non_camel_case_types)]
-        #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug)]
+        #[derive(Clone, Eq, PartialEq, Copy, Hash, RustcEncodable, Debug, HeapSizeOf)]
         pub enum $name {
             $( $variant ),+
         }
@@ -43,7 +43,7 @@ macro_rules! define_numbered_css_keyword_enum {
     };
     ($name: ident: $( $css: expr => $variant: ident = $value: expr ),+) => {
         #[allow(non_camel_case_types)]
-        #[derive(Clone, Eq, PartialEq, PartialOrd, Ord, Copy, RustcEncodable, Debug)]
+        #[derive(Clone, Eq, PartialEq, PartialOrd, Ord, Copy, RustcEncodable, Debug, HeapSizeOf)]
         pub enum $name {
             $( $variant = $value ),+
         }
@@ -68,7 +68,6 @@ macro_rules! define_numbered_css_keyword_enum {
     }
 }
 
-
 pub type CSSFloat = f32;
 
 
@@ -607,7 +606,7 @@ pub mod specified {
         }
     }
 
-    #[derive(Clone, PartialEq, PartialOrd, Copy, Debug)]
+    #[derive(Clone, PartialEq, PartialOrd, Copy, Debug, HeapSizeOf)]
     pub struct Angle(pub CSSFloat);
 
     impl ToCss for Angle {

components/util/mem.rs

@@ -9,6 +9,13 @@ use std::collections::LinkedList;
 use std::mem::transmute;
 use std::sync::Arc;
 
+
+use azure::azure_hl::Color;
+use cursor::Cursor;
+use geom::{Point2D, Rect, SideOffsets2D, Size2D, Matrix2D, Matrix4};
+use geometry::Au;
+use range::Range;
+
 extern {
     // Get the size of a heap block.
     //
@@ -35,9 +42,6 @@ pub fn heap_size_of(ptr: *const c_void) -> usize {
 // return multiple measurements -- e.g. measure text separately from images -- are also possible,
 // and should be used when appropriate.
 //
-// FIXME(njn): it would be nice to be able to derive this trait automatically, given that
-// implementations are mostly repetitive and mechanical.
-//
 pub trait HeapSizeOf {
     /// Measure the size of any heap-allocated structures that hang off this value, but not the
     /// space taken up by the value itself (i.e. what size_of::<T> measures, more or less); that
@@ -158,3 +162,38 @@ impl<T> Drop for LinkedList2<T> {
     fn drop(&mut self) {}
 }
 
+/// For use on types defined in external crates
+/// with known heap sizes.
+#[macro_export]
+macro_rules! known_heap_size(
+    ($size:expr, $($ty:ident),+) => (
+        $(
+            impl $crate::mem::HeapSizeOf for $ty {
+                #[inline(always)]
+                fn heap_size_of_children(&self) -> usize {
+                    $size
+                }
+            }
+        )+
+    );
+    ($size: expr, $($ty:ident<$($gen:ident),+>),+) => (
+        $(
+        impl<$($gen: $crate::mem::HeapSizeOf),+> $crate::mem::HeapSizeOf for $ty<$($gen),+> {
+            #[inline(always)]
+            fn heap_size_of_children(&self) -> usize {
+                $size
+            }
+        }
+        )+
+    );
+);
+
+
+known_heap_size!(0, u8, u16, u32, u64, usize);
+known_heap_size!(0, i8, i16, i32, i64, isize);
+known_heap_size!(0, bool, f32, f64);
+
+known_heap_size!(0, Rect<T>, Point2D<T>, Size2D<T>, Matrix2D<T>, SideOffsets2D<T>, Matrix4<T>);
+
+known_heap_size!(0, Au, Color, Cursor);
+known_heap_size!(0, Range<T>);

tests/unit/util/Cargo.toml

@@ -11,5 +11,9 @@ doctest = false
 [dependencies.util]
 path = "../../../components/util"
 
+
+[dependencies.plugins]
+path = "../../../components/plugins"
+
 [dependencies.geom]
 git = "https://github.com/servo/rust-geom"

tests/unit/util/lib.rs

@@ -2,6 +2,8 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+#![feature(plugin, custom_derive, custom_attributes)]
+#![plugin(plugins)]
 extern crate util;
 extern crate geom;
 
@@ -9,3 +11,4 @@ extern crate geom;
 #[cfg(test)] mod logical_geometry;
 #[cfg(test)] mod task;
 #[cfg(test)] mod vec;
+#[cfg(test)] mod mem;

tests/unit/util/mem.rs

@@ -0,0 +1,33 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+use util::mem::HeapSizeOf;
+
+
+struct Four;
+impl HeapSizeOf for Four {
+    fn heap_size_of_children(&self) -> usize {
+        4
+    }
+}
+
+#[derive(HeapSizeOf)]
+struct Eight(Four, Four, bool, bool, bool);
+
+#[derive(HeapSizeOf)]
+enum EightOrFour {
+    Eight(Eight),
+    Four(Four),
+    Zero(u8)
+}
+
+#[test]
+fn test_heap_size() {
+    assert_eq!(Four.heap_size_of_children(), 4);
+    let eight = Eight(Four, Four, true, true, true);
+    assert_eq!(eight.heap_size_of_children(), 8);
+    assert_eq!(EightOrFour::Eight(eight).heap_size_of_children(), 8);
+    assert_eq!(EightOrFour::Four(Four).heap_size_of_children(), 4);
+    assert_eq!(EightOrFour::Zero(1).heap_size_of_children(), 0);
+}