Implement StructuredCloneData::write.

components/script/dom/bindings/structuredclone.rs

@@ -2,7 +2,15 @@
  * 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 dom::bindings::error::Fallible;
+use dom::bindings::error::Error::DataClone;
+
+use js::jsapi::JSContext;
+use js::jsapi::{JS_WriteStructuredClone, JS_ClearPendingException};
+use js::jsval::JSVal;
+
 use libc::size_t;
+use std::ptr;
 
 #[allow(raw_pointer_deriving)]
 #[deriving(Copy)]
@@ -10,3 +18,23 @@ pub struct StructuredCloneData {
     pub data: *mut u64,
     pub nbytes: size_t,
 }
+
+impl StructuredCloneData {
+    pub fn write(cx: *mut JSContext, message: JSVal)
+                 -> Fallible<StructuredCloneData> {
+        let mut data = ptr::null_mut();
+        let mut nbytes = 0;
+        let result = unsafe {
+            JS_WriteStructuredClone(cx, message, &mut data, &mut nbytes,
+                                    ptr::null(), ptr::null_mut())
+        };
+        if result == 0 {
+            unsafe { JS_ClearPendingException(cx); }
+            return Err(DataClone);
+        }
+        Ok(StructuredCloneData {
+            data: data,
+            nbytes: nbytes,
+        })
+    }
+}