1 files changed, 105 insertions, 0 deletions
diff --git a/servo/components/style/gecko_string_cache/namespace.rs b/servo/components/style/gecko_string_cache/namespace.rs
new file mode 100644
index 0000000000..d9745b9e21
--- /dev/null
+++ b/servo/components/style/gecko_string_cache/namespace.rs
@@ -0,0 +1,105 @@
+/* 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 https://mozilla.org/MPL/2.0/. */
+
+//! A type to represent a namespace.
+
+use crate::gecko_bindings::structs::nsAtom;
+use crate::string_cache::{Atom, WeakAtom};
+use precomputed_hash::PrecomputedHash;
+use std::borrow::Borrow;
+use std::fmt;
+use std::ops::Deref;
+
+/// In Gecko namespaces are just regular atoms, so this is a simple macro to
+/// forward one macro to the other.
+#[macro_export]
+macro_rules! ns {
+    () => {
+        $crate::string_cache::Namespace(atom!(""))
+    };
+    ($s:tt) => {
+        $crate::string_cache::Namespace(atom!($s))
+    };
+}
+
+/// A Gecko namespace is just a wrapped atom.
+#[derive(
+    Clone,
+    Debug,
+    Default,
+    Eq,
+    Hash,
+    MallocSizeOf,
+    PartialEq,
+    ToComputedValue,
+    ToResolvedValue,
+    ToShmem,
+)]
+#[repr(transparent)]
+pub struct Namespace(pub Atom);
+
+impl PrecomputedHash for Namespace {
+    #[inline]
+    fn precomputed_hash(&self) -> u32 {
+        self.0.precomputed_hash()
+    }
+}
+
+/// A Gecko WeakNamespace is a wrapped WeakAtom.
+#[derive(Deref, Hash)]
+pub struct WeakNamespace(WeakAtom);
+
+impl Deref for Namespace {
+    type Target = WeakNamespace;
+
+    #[inline]
+    fn deref(&self) -> &WeakNamespace {
+        let weak: *const WeakAtom = &*self.0;
+        unsafe { &*(weak as *const WeakNamespace) }
+    }
+}
+
+impl<'a> From<&'a str> for Namespace {
+    fn from(s: &'a str) -> Self {
+        Namespace(Atom::from(s))
+    }
+}
+
+impl fmt::Display for Namespace {
+    fn fmt(&self, w: &mut fmt::Formatter) -> fmt::Result {
+        self.0.fmt(w)
+    }
+}
+
+impl Borrow<WeakNamespace> for Namespace {
+    #[inline]
+    fn borrow(&self) -> &WeakNamespace {
+        self
+    }
+}
+
+impl WeakNamespace {
+    /// Trivially construct a WeakNamespace.
+    #[inline]
+    pub unsafe fn new<'a>(atom: *mut nsAtom) -> &'a Self {
+        &*(atom as *const WeakNamespace)
+    }
+
+    /// Clone this WeakNamespace to obtain a strong reference to the same
+    /// underlying namespace.
+    #[inline]
+    pub fn clone(&self) -> Namespace {
+        Namespace(self.0.clone())
+    }
+}
+
+impl Eq for WeakNamespace {}
+impl PartialEq for WeakNamespace {
+    #[inline]
+    fn eq(&self, other: &Self) -> bool {
+        let weak: *const WeakNamespace = self;
+        let other: *const WeakNamespace = other;
+        weak == other
+    }
+}