Implement JSManaged for DOM objects.

src/components/script/dom/bindings/js.rs

@@ -0,0 +1,99 @@
+/* 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 dom::bindings::utils::{Reflector, Reflectable};
+use dom::window;
+use js::jsapi::{JSContext, JSObject};
+use layout_interface::TrustedNodeAddress;
+
+use std::cast;
+use std::cell::RefCell;
+use std::unstable::raw::Box;
+
+pub struct JS<T> {
+    priv ptr: RefCell<*mut T>
+}
+
+impl<T> Eq for JS<T> {
+    fn eq(&self, other: &JS<T>) -> bool {
+        self.ptr == other.ptr
+    }
+}
+
+impl <T> Clone for JS<T> {
+    fn clone(&self) -> JS<T> {
+        JS {
+            ptr: self.ptr.clone()
+        }
+    }
+}
+
+impl<T: Reflectable> JS<T> {
+    pub fn new(mut obj: ~T,
+               window:  &window::Window,
+               wrap_fn: extern "Rust" fn(*JSContext, *JSObject, ~T) -> *JSObject) -> JS<T> {
+        let cx = window.get_cx();
+        let scope = window.reflector().get_jsobject();
+        let raw: *mut T = &mut *obj;
+        if wrap_fn(cx, scope, obj).is_null() {
+            fail!("Could not eagerly wrap object");
+        }
+        JS {
+            ptr: RefCell::new(raw)
+        }
+    }
+
+    pub unsafe fn from_raw(raw: *mut T) -> JS<T> {
+        JS {
+            ptr: RefCell::new(raw)
+        }
+    }
+
+
+    pub unsafe fn from_box(box_: *mut Box<T>) -> JS<T> {
+        let raw: *mut T = &mut (*box_).data;
+        JS {
+            ptr: RefCell::new(raw)
+        }
+    }
+
+    pub unsafe fn from_trusted_node_address(inner: TrustedNodeAddress) -> JS<T> {
+        JS {
+            ptr: RefCell::new(inner as *mut T)
+        }
+    }
+}
+
+impl<T: Reflectable> Reflectable for JS<T> {
+    fn reflector<'a>(&'a self) -> &'a Reflector {
+        self.get().reflector()
+    }
+
+    fn mut_reflector<'a>(&'a mut self) -> &'a mut Reflector {
+        self.get_mut().mut_reflector()
+    }
+}
+
+impl<T> JS<T> {
+    pub fn get<'a>(&'a self) -> &'a T {
+        let borrowed = self.ptr.borrow();
+        unsafe {
+            &(**borrowed.get())
+        }
+    }
+
+    pub fn get_mut<'a>(&'a mut self) -> &'a mut T {
+        let mut borrowed = self.ptr.borrow_mut();
+        unsafe {
+            &mut (**borrowed.get())
+        }
+    }
+}
+
+impl<From, To> JS<From> {
+    //XXXjdm It would be lovely if this could be private.
+    pub unsafe fn transmute(self) -> JS<To> {
+        cast::transmute(self)
+    }
+}