bool
JSCompartment::wrap(JSContext *cx, Value *vp)
{
JS_ASSERT(cx->compartment == this);
uintN flags = 0;
JS_CHECK_RECURSION(cx, return false);
/* Only GC things have to be wrapped or copied. */
if (!vp->isMarkable())
return true;
/* Static strings do not have to be wrapped. */
if (vp->isString() && JSString::isStatic(vp->toString()))
return true;
/* Unwrap incoming objects. */
if (vp->isObject()) {
JSObject *obj = &vp->toObject();
/* If the object is already in this compartment, we are done. */
if (obj->getCompartment(cx) == this)
return true;
/* Don't unwrap an outer window proxy. */
if (!obj->getClass()->ext.innerObject) {
obj = vp->toObject().unwrap(&flags);
OBJ_TO_OUTER_OBJECT(cx, obj);
if (!obj)
return false;
vp->setObject(*obj);
}
/* If the wrapped object is already in this compartment, we are done. */
if (obj->getCompartment(cx) == this)
return true;
}
/* If we already have a wrapper for this value, use it. */
if (WrapperMap::Ptr p = crossCompartmentWrappers.lookup(*vp)) {
*vp = p->value;
return true;
}
if (vp->isString()) {
Value orig = *vp;
JSString *str = vp->toString();
JSString *wrapped = js_NewStringCopyN(cx, str->chars(), str->length());
if (!wrapped)
return false;
vp->setString(wrapped);
return crossCompartmentWrappers.put(orig, *vp);
}
JSObject *obj = &vp->toObject();
/*
* Recurse to wrap the prototype. Long prototype chains will run out of
* stack, causing an error in CHECK_RECURSE.
*
* Wrapping the proto before creating the new wrapper and adding it to the
* cache helps avoid leaving a bad entry in the cache on OOM. But note that
* if we wrapped both proto and parent, we would get infinite recursion
* here (since Object.prototype->parent->proto leads to Object.prototype
* itself).
*/
JSObject *proto = obj->getProto();
if (!wrap(cx, &proto))
return false;
/*
* We hand in the original wrapped object into the wrap hook to allow
* the wrap hook to reason over what wrappers are currently applied
* to the object.
*/
JSObject *wrapper = cx->runtime->wrapObjectCallback(cx, obj, proto, flags);
if (!wrapper)
return false;
wrapper->setProto(proto);
vp->setObject(*wrapper);
if (!crossCompartmentWrappers.put(wrapper->getProxyPrivate(), *vp))
return false;
/*
* Wrappers should really be parented to the wrapped parent of the wrapped
* object, but in that case a wrapped global object would have a NULL
* parent without being a proper global object (JSCLASS_IS_GLOBAL). Instead,
* we parent all wrappers to the global object in their home compartment.
* This loses us some transparency, and is generally very cheesy.
*/
JSObject *global;
if (cx->hasfp()) {
global = cx->fp()->scopeChain().getGlobal();
} else {
global = cx->globalObject;
OBJ_TO_INNER_OBJECT(cx, global);
if (!global)
return false;
}
wrapper->setParent(global);
return true;
}
