1 files changed, 64 insertions, 0 deletions
diff --git a/components/style/namespaces.rs b/components/style/namespaces.rs
new file mode 100644
index 00000000000..6ea1e4b4c3a
--- /dev/null
+++ b/components/style/namespaces.rs
@@ -0,0 +1,64 @@
+/* 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 cssparser::ast::*;
+use std::collections::hashmap::HashMap;
+use servo_util::namespace::Namespace;
+use errors::log_css_error;
+
+pub struct NamespaceMap {
+    pub default: Option<Namespace>,
+    pub prefix_map: HashMap<String, Namespace>,
+}
+
+
+impl NamespaceMap {
+    pub fn new() -> NamespaceMap {
+        NamespaceMap { default: None, prefix_map: HashMap::new() }
+    }
+}
+
+
+pub fn parse_namespace_rule(rule: AtRule, namespaces: &mut NamespaceMap) {
+    let location = rule.location;
+    macro_rules! syntax_error(
+        () => {{
+            log_css_error(location, "Invalid @namespace rule");
+            return
+        }};
+    );
+    if rule.block.is_some() { syntax_error!() }
+    let mut prefix: Option<String> = None;
+    let mut ns: Option<Namespace> = None;
+    let mut iter = rule.prelude.move_skip_whitespace();
+    for component_value in iter {
+        match component_value {
+            Ident(value) => {
+                if prefix.is_some() { syntax_error!() }
+                prefix = Some(value.into_string());
+            },
+            URL(value) | String(value) => {
+                if ns.is_some() { syntax_error!() }
+                ns = Some(Namespace::from_str(value.as_slice()));
+                break
+            },
+            _ => syntax_error!(),
+        }
+    }
+    if iter.next().is_some() { syntax_error!() }
+    match (prefix, ns) {
+        (Some(prefix), Some(ns)) => {
+            if namespaces.prefix_map.swap(prefix, ns).is_some() {
+                log_css_error(location, "Duplicate @namespace rule");
+            }
+        },
+        (None, Some(ns)) => {
+            if namespaces.default.is_some() {
+                log_css_error(location, "Duplicate @namespace rule");
+            }
+            namespaces.default = Some(ns);
+        },
+        _ => syntax_error!()
+    }
+}