Bug 973780 - Implement an expando WeakMap on XPCWrappedNativeScope. r=mccr8

js/xpconnect/src/XPCWrappedNativeScope.cpp

@@ -302,6 +302,9 @@ XPCWrappedNativeScope::~XPCWrappedNativeScope()
     // XXX might not want to do this at xpconnect shutdown time???
     mComponents = nullptr;
 
+    if (mXrayExpandos.initialized())
+        mXrayExpandos.destroy();
+
     JSRuntime *rt = XPCJSRuntime::Get()->Runtime();
     mXBLScope.finalize(rt);
     mGlobalJSObject.finalize(rt);
@@ -599,6 +602,27 @@ XPCWrappedNativeScope::RemoveWrappedNativeProtos()
                                       GetRuntime()->GetDetachedWrappedNativeProtoMap());
 }
 
+JSObject *
+XPCWrappedNativeScope::GetExpandoChain(JSObject *target)
+{
+    MOZ_ASSERT(GetObjectScope(target) == this);
+    if (!mXrayExpandos.initialized())
+        return nullptr;
+    return mXrayExpandos.lookup(target);
+}
+
+bool
+XPCWrappedNativeScope::SetExpandoChain(JSContext *cx, HandleObject target,
+                                       HandleObject chain)
+{
+    MOZ_ASSERT(GetObjectScope(target) == this);
+    MOZ_ASSERT(js::IsObjectInContextCompartment(target, cx));
+    MOZ_ASSERT_IF(chain, GetObjectScope(chain) == this);
+    if (!mXrayExpandos.initialized() && !mXrayExpandos.init(cx))
+        return false;
+    return mXrayExpandos.put(target, chain);
+}
+
 /***************************************************************************/
 
 // static

js/xpconnect/src/xpcprivate.h

@@ -90,6 +90,7 @@
 
 #include "xpcpublic.h"
 #include "js/Tracer.h"
+#include "js/WeakMapPtr.h"
 #include "pldhash.h"
 #include "nscore.h"
 #include "nsXPCOM.h"
@@ -1037,6 +1038,12 @@ public:
         return nsJSPrincipals::get(JS_GetCompartmentPrincipals(c));
     }
 
+    JSObject*
+    GetExpandoChain(JSObject *target);
+
+    bool
+    SetExpandoChain(JSContext *cx, JS::HandleObject target, JS::HandleObject chain);
+
     void RemoveWrappedNativeProtos();
 
     static void
@@ -1050,6 +1057,8 @@ public:
         mGlobalJSObject.trace(trc, "XPCWrappedNativeScope::mGlobalJSObject");
         if (mXBLScope)
             mXBLScope.trace(trc, "XPCWrappedNativeScope::mXBLScope");
+        if (mXrayExpandos.initialized())
+            mXrayExpandos.trace(trc);
     }
 
     static void
@@ -1169,6 +1178,8 @@ private:
 
     nsAutoPtr<DOMExpandoSet> mDOMExpandoSet;
 
+    JS::WeakMapPtr<JSObject*, JSObject*> mXrayExpandos;
+
     bool mIsXBLScope;
 
     // For remote XUL domains, we run all XBL in the content scope for compat