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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* 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/. */
#include "vm/ProxyObject.h"
#include "jscompartment.h"
#include "proxy/DeadObjectProxy.h"
#include "proxy/ScriptedProxyHandler.h"
#include "jsobjinlines.h"
using namespace js;
/* static */ ProxyObject*
ProxyObject::New(JSContext* cx, const BaseProxyHandler* handler, HandleValue priv, TaggedProto proto_,
const ProxyOptions& options)
{
Rooted<TaggedProto> proto(cx, proto_);
const Class* clasp = options.clasp();
MOZ_ASSERT(isValidProxyClass(clasp));
MOZ_ASSERT(clasp->shouldDelayMetadataBuilder());
MOZ_ASSERT_IF(proto.isObject(), cx->compartment() == proto.toObject()->compartment());
MOZ_ASSERT(clasp->hasFinalize());
/*
* Eagerly mark properties unknown for proxies, so we don't try to track
* their properties and so that we don't need to walk the compartment if
* their prototype changes later. But don't do this for DOM proxies,
* because we want to be able to keep track of them in typesets in useful
* ways.
*/
if (proto.isObject() && !options.singleton() && !clasp->isDOMClass()) {
RootedObject protoObj(cx, proto.toObject());
if (!JSObject::setNewGroupUnknown(cx, clasp, protoObj))
return nullptr;
}
// Ensure that the wrapper has the same lifetime assumptions as the
// wrappee. Prefer to allocate in the nursery, when possible.
NewObjectKind newKind = NurseryAllocatedProxy;
if (options.singleton()) {
MOZ_ASSERT(priv.isNull() || (priv.isGCThing() && priv.toGCThing()->isTenured()));
newKind = SingletonObject;
} else if ((priv.isGCThing() && priv.toGCThing()->isTenured()) ||
!handler->canNurseryAllocate() ||
!handler->finalizeInBackground(priv))
{
newKind = TenuredObject;
}
gc::AllocKind allocKind = gc::GetGCObjectKind(clasp);
if (handler->finalizeInBackground(priv))
allocKind = GetBackgroundAllocKind(allocKind);
AutoSetNewObjectMetadata metadata(cx);
// Note: this will initialize the object's |data| to strange values, but we
// will immediately overwrite those below.
RootedObject obj(cx, NewObjectWithGivenTaggedProto(cx, clasp, proto, allocKind,
newKind));
if (!obj)
return nullptr;
Rooted<ProxyObject*> proxy(cx, &obj->as<ProxyObject>());
new (proxy->data.values) detail::ProxyValueArray;
proxy->data.handler = handler;
proxy->setCrossCompartmentPrivate(priv);
/* Don't track types of properties of non-DOM and non-singleton proxies. */
if (newKind != SingletonObject && !clasp->isDOMClass())
MarkObjectGroupUnknownProperties(cx, proxy->group());
return proxy;
}
gc::AllocKind
ProxyObject::allocKindForTenure() const
{
gc::AllocKind allocKind = gc::GetGCObjectKind(group()->clasp());
if (data.handler->finalizeInBackground(const_cast<ProxyObject*>(this)->private_()))
allocKind = GetBackgroundAllocKind(allocKind);
return allocKind;
}
/* static */ size_t
ProxyObject::objectMovedDuringMinorGC(TenuringTracer* trc, JSObject* dst, JSObject* src)
{
ProxyObject& psrc = src->as<ProxyObject>();
ProxyObject& pdst = dst->as<ProxyObject>();
// We're about to sweep the nursery heap, so migrate the inline
// ProxyValueArray to the malloc heap if they were nursery allocated.
if (trc->runtime()->gc.nursery.isInside(psrc.data.values))
pdst.data.values = js_new<detail::ProxyValueArray>(*psrc.data.values);
else
trc->runtime()->gc.nursery.removeMallocedBuffer(psrc.data.values);
return sizeof(detail::ProxyValueArray);
}
void
ProxyObject::setCrossCompartmentPrivate(const Value& priv)
{
*slotOfPrivate() = priv;
}
void
ProxyObject::setSameCompartmentPrivate(const Value& priv)
{
MOZ_ASSERT(IsObjectValueInCompartment(priv, compartment()));
*slotOfPrivate() = priv;
}
void
ProxyObject::nuke()
{
// When nuking scripted proxies, isCallable and isConstructor values for
// the proxy needs to be preserved. Do this before clearing the target.
uint32_t callable = handler()->isCallable(this)
? ScriptedProxyHandler::IS_CALLABLE : 0;
uint32_t constructor = handler()->isConstructor(this)
? ScriptedProxyHandler::IS_CONSTRUCTOR : 0;
setExtra(ScriptedProxyHandler::IS_CALLCONSTRUCT_EXTRA,
PrivateUint32Value(callable | constructor));
// Clear the target reference.
setSameCompartmentPrivate(NullValue());
// Update the handler to make this a DeadObjectProxy.
setHandler(&DeadObjectProxy::singleton);
// The proxy's extra slots are not cleared and will continue to be
// traced. This avoids the possibility of triggering write barriers while
// nuking proxies in dead compartments which could otherwise cause those
// compartments to be kept alive. Note that these are slots cannot hold
// cross compartment pointers, so this cannot cause the target compartment
// to leak.
}
JS_FRIEND_API(void)
js::SetValueInProxy(Value* slot, const Value& value)
{
// Slots in proxies are not GCPtrValues, so do a cast whenever assigning
// values to them which might trigger a barrier.
*reinterpret_cast<GCPtrValue*>(slot) = value;
}
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