derive(HeapSizeOf).

.travis.yml

@@ -9,6 +9,7 @@ script:
   - cargo test
   - cargo test --features log-events
   - "if [ $TRAVIS_RUST_VERSION = nightly ]; then cargo test --features unstable; fi"
+  - "if [ $TRAVIS_RUST_VERSION = nightly ]; then cargo test --features heap_size; fi"
   - "cd examples/summarize-events/ && cargo build"
 notifications:
   webhooks: http://build.servo.org:54856/travis

Cargo.toml

@@ -24,6 +24,9 @@ log-events = ["rustc-serialize"]
 # Use unstable features to optimize space and time (memory and CPU usage).
 unstable = ["string_cache_plugin"]
 
+# HeapSizeOf support
+heap_size = ["heapsize", "heapsize_plugin"]
+
 [dependencies]
 lazy_static = "0.1.10"
 serde = "0.5"
@@ -44,6 +47,14 @@ optional = true
 path = "shared"
 version = "0.1.4"
 
+[dependencies.heapsize]
+version = "0.1.1"
+optional = true
+
+[dependencies.heapsize_plugin]
+version = "0.0.1"
+optional = true
+
 [build-dependencies.string_cache_shared]
 path = "shared"
 version = "0.1.4"

src/atom/mod.rs

@@ -133,6 +133,7 @@ impl StringCache {
 // NOTE: Deriving Eq here implies that a given string must always
 // be interned the same way.
 #[cfg_attr(feature = "unstable", unsafe_no_drop_flag)]  // See tests::atom_drop_is_idempotent
+#[cfg_attr(feature = "heap_size", derive(HeapSizeOf))]
 #[derive(Eq, Hash, PartialEq)]
 pub struct Atom {
     /// This field is public so that the `atom!()` macro can use it.

src/lib.rs

@@ -13,7 +13,9 @@
 #![cfg_attr(test, deny(warnings))]
 #![cfg_attr(all(test, feature = "unstable"), feature(test, filling_drop))]
 #![cfg_attr(feature = "unstable", feature(unsafe_no_drop_flag, plugin))]
+#![cfg_attr(feature = "heap_size", feature(plugin, custom_derive))]
 #![cfg_attr(feature = "unstable", plugin(string_cache_plugin))]
+#![cfg_attr(feature = "heap_size", plugin(heapsize_plugin))]
 
 #[cfg(all(test, feature = "unstable"))]
 extern crate test;
@@ -27,6 +29,9 @@ extern crate rand;
 #[cfg(feature = "log-events")]
 extern crate rustc_serialize;
 
+#[cfg(feature = "heap_size")]
+extern crate heapsize;
+
 extern crate serde;
 
 extern crate string_cache_shared;

src/namespace.rs

@@ -15,6 +15,7 @@ use atom::Atom;
 /// Whether a given string represents a namespace is contextual, so this is
 /// a transparent wrapper that will not catch all mistakes.
 #[derive(PartialEq, Eq, PartialOrd, Ord, Hash, Debug, Clone)]
+#[cfg_attr(feature = "heap_size", derive(HeapSizeOf))]
 pub struct Namespace(pub Atom);
 
 /// A name with a namespace.