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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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,
#include "mozilla/dom/DOMJSProxyHandler.h"
#include "xpcpublic.h"
#include "xpcprivate.h"
#include "XPCWrapper.h"
#include "WrapperFactory.h"
#include "nsWrapperCacheInlines.h"
#include "mozilla/dom/BindingUtils.h"
#include "jsapi.h"
#include "js/friend/DOMProxy.h" // JS::DOMProxyShadowsResult, JS::ExpandoAndGeneration, JS::SetDOMProxyInformation
#include "js/PropertyAndElement.h" // JS_AlreadyHasOwnPropertyById, JS_DefineProperty, JS_DefinePropertyById, JS_DeleteProperty, JS_DeletePropertyById
#include "js/Object.h" // JS::GetCompartment
using namespace JS;
namespace mozilla::dom {
jsid s_length_id = JS::PropertyKey::Void();
bool DefineStaticJSVals(JSContext* cx) {
return AtomizeAndPinJSString(cx, s_length_id, "length");
}
const char DOMProxyHandler::family = 0;
JS::DOMProxyShadowsResult DOMProxyShadows(JSContext* cx,
JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id) {
using DOMProxyShadowsResult = JS::DOMProxyShadowsResult;
JS::Rooted<JSObject*> expando(cx, DOMProxyHandler::GetExpandoObject(proxy));
JS::Value v = js::GetProxyPrivate(proxy);
bool isOverrideBuiltins = !v.isObject() && !v.isUndefined();
if (expando) {
bool hasOwn;
if (!JS_AlreadyHasOwnPropertyById(cx, expando, id, &hasOwn))
return DOMProxyShadowsResult::ShadowCheckFailed;
if (hasOwn) {
return isOverrideBuiltins
? DOMProxyShadowsResult::ShadowsViaIndirectExpando
: DOMProxyShadowsResult::ShadowsViaDirectExpando;
}
}
if (!isOverrideBuiltins) {
// Our expando, if any, didn't shadow, so we're not shadowing at all.
return DOMProxyShadowsResult::DoesntShadow;
}
bool hasOwn;
if (!GetProxyHandler(proxy)->hasOwn(cx, proxy, id, &hasOwn))
return DOMProxyShadowsResult::ShadowCheckFailed;
return hasOwn ? DOMProxyShadowsResult::Shadows
: DOMProxyShadowsResult::DoesntShadowUnique;
}
// Store the information for the specialized ICs.
struct SetDOMProxyInformation {
SetDOMProxyInformation() {
JS::SetDOMProxyInformation((const void*)&DOMProxyHandler::family,
DOMProxyShadows,
&RemoteObjectProxyBase::sCrossOriginProxyFamily);
}
};
SetDOMProxyInformation gSetDOMProxyInformation;
static inline void CheckExpandoObject(JSObject* proxy,
const JS::Value& expando) {
#ifdef DEBUG
JSObject* obj = &expando.toObject();
MOZ_ASSERT(!js::gc::EdgeNeedsSweepUnbarriered(&obj));
MOZ_ASSERT(JS::GetCompartment(proxy) == JS::GetCompartment(obj));
// When we create an expando object in EnsureExpandoObject below, we preserve
// the wrapper. The wrapper is released when the object is unlinked, but we
// should never call these functions after that point.
nsISupports* native = UnwrapDOMObject<nsISupports>(proxy);
nsWrapperCache* cache;
// QueryInterface to nsWrapperCache will not GC.
JS::AutoSuppressGCAnalysis suppress;
CallQueryInterface(native, &cache);
MOZ_ASSERT(cache->PreservingWrapper());
#endif
}
static inline void CheckExpandoAndGeneration(
JSObject* proxy, JS::ExpandoAndGeneration* expandoAndGeneration) {
#ifdef DEBUG
JS::Value value = expandoAndGeneration->expando;
if (!value.isUndefined()) CheckExpandoObject(proxy, value);
#endif
}
static inline void CheckDOMProxy(JSObject* proxy) {
#ifdef DEBUG
MOZ_ASSERT(IsDOMProxy(proxy), "expected a DOM proxy object");
MOZ_ASSERT(!js::gc::EdgeNeedsSweepUnbarriered(&proxy));
nsISupports* native = UnwrapDOMObject<nsISupports>(proxy);
nsWrapperCache* cache;
// QI to nsWrapperCache cannot GC for very non-obvious reasons; see
JS::AutoSuppressGCAnalysis nogc;
CallQueryInterface(native, &cache);
MOZ_ASSERT(cache->GetWrapperPreserveColor() == proxy);
#endif
}
// static
JSObject* DOMProxyHandler::GetAndClearExpandoObject(JSObject* obj) {
CheckDOMProxy(obj);
JS::Value v = js::GetProxyPrivate(obj);
if (v.isUndefined()) {
return nullptr;
}
if (v.isObject()) {
js::SetProxyPrivate(obj, UndefinedValue());
} else {
auto* expandoAndGeneration =
static_cast<JS::ExpandoAndGeneration*>(v.toPrivate());
v = expandoAndGeneration->expando;
if (v.isUndefined()) {
return nullptr;
}
expandoAndGeneration->expando = UndefinedValue();
}
CheckExpandoObject(obj, v);
return &v.toObject();
}
// static
JSObject* DOMProxyHandler::EnsureExpandoObject(JSContext* cx,
JS::Handle<JSObject*> obj) {
CheckDOMProxy(obj);
JS::Value v = js::GetProxyPrivate(obj);
if (v.isObject()) {
CheckExpandoObject(obj, v);
return &v.toObject();
}
JS::ExpandoAndGeneration* expandoAndGeneration = nullptr;
if (!v.isUndefined()) {
expandoAndGeneration =
static_cast<JS::ExpandoAndGeneration*>(v.toPrivate());
CheckExpandoAndGeneration(obj, expandoAndGeneration);
if (expandoAndGeneration->expando.isObject()) {
return &expandoAndGeneration->expando.toObject();
}
}
JS::Rooted<JSObject*> expando(
cx, JS_NewObjectWithGivenProto(cx, nullptr, nullptr));
if (!expando) {
return nullptr;
}
nsISupports* native = UnwrapDOMObject<nsISupports>(obj);
nsWrapperCache* cache;
CallQueryInterface(native, &cache);
cache->PreserveWrapper(native);
if (expandoAndGeneration) {
expandoAndGeneration->expando.setObject(*expando);
return expando;
}
js::SetProxyPrivate(obj, ObjectValue(*expando));
return expando;
}
bool DOMProxyHandler::preventExtensions(JSContext* cx,
JS::Handle<JSObject*> proxy,
JS::ObjectOpResult& result) const {
// always extensible per WebIDL
return result.failCantPreventExtensions();
}
bool DOMProxyHandler::isExtensible(JSContext* cx, JS::Handle<JSObject*> proxy,
bool* extensible) const {
*extensible = true;
return true;
}
bool BaseDOMProxyHandler::getOwnPropertyDescriptor(
JSContext* cx, Handle<JSObject*> proxy, Handle<jsid> id,
MutableHandle<Maybe<PropertyDescriptor>> desc) const {
return getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ false,
desc);
}
bool DOMProxyHandler::defineProperty(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
Handle<PropertyDescriptor> desc,
JS::ObjectOpResult& result,
bool* done) const {
if (xpc::WrapperFactory::IsXrayWrapper(proxy)) {
return result.succeed();
}
JS::Rooted<JSObject*> expando(cx, EnsureExpandoObject(cx, proxy));
if (!expando) {
return false;
}
if (!JS_DefinePropertyById(cx, expando, id, desc, result)) {
return false;
}
*done = true;
return true;
}
bool DOMProxyHandler::set(JSContext* cx, Handle<JSObject*> proxy,
Handle<jsid> id, Handle<JS::Value> v,
Handle<JS::Value> receiver,
ObjectOpResult& result) const {
MOZ_ASSERT(!xpc::WrapperFactory::IsXrayWrapper(proxy),
"Should not have a XrayWrapper here");
bool done;
if (!setCustom(cx, proxy, id, v, &done)) {
return false;
}
if (done) {
return result.succeed();
}
// Make sure to ignore our named properties when checking for own
// property descriptors for a set.
Rooted<Maybe<PropertyDescriptor>> ownDesc(cx);
if (!getOwnPropDescriptor(cx, proxy, id, /* ignoreNamedProps = */ true,
&ownDesc)) {
return false;
}
return js::SetPropertyIgnoringNamedGetter(cx, proxy, id, v, receiver, ownDesc,
result);
}
bool DOMProxyHandler::delete_(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id,
JS::ObjectOpResult& result) const {
JS::Rooted<JSObject*> expando(cx);
if (!xpc::WrapperFactory::IsXrayWrapper(proxy) &&
(expando = GetExpandoObject(proxy))) {
return JS_DeletePropertyById(cx, expando, id, result);
}
return result.succeed();
}
bool BaseDOMProxyHandler::ownPropertyKeys(
JSContext* cx, JS::Handle<JSObject*> proxy,
JS::MutableHandleVector<jsid> props) const {
return ownPropNames(cx, proxy,
JSITER_OWNONLY | JSITER_HIDDEN | JSITER_SYMBOLS, props);
}
bool BaseDOMProxyHandler::getPrototypeIfOrdinary(
JSContext* cx, JS::Handle<JSObject*> proxy, bool* isOrdinary,
JS::MutableHandle<JSObject*> proto) const {
*isOrdinary = true;
proto.set(GetStaticPrototype(proxy));
return true;
}
bool BaseDOMProxyHandler::getOwnEnumerablePropertyKeys(
JSContext* cx, JS::Handle<JSObject*> proxy,
JS::MutableHandleVector<jsid> props) const {
return ownPropNames(cx, proxy, JSITER_OWNONLY, props);
}
bool DOMProxyHandler::setCustom(JSContext* cx, JS::Handle<JSObject*> proxy,
JS::Handle<jsid> id, JS::Handle<JS::Value> v,
bool* done) const {
*done = false;
return true;
}
// static
JSObject* DOMProxyHandler::GetExpandoObject(JSObject* obj) {
CheckDOMProxy(obj);
JS::Value v = js::GetProxyPrivate(obj);
if (v.isObject()) {
CheckExpandoObject(obj, v);
return &v.toObject();
}
if (v.isUndefined()) {
return nullptr;
}
auto* expandoAndGeneration =
static_cast<JS::ExpandoAndGeneration*>(v.toPrivate());
CheckExpandoAndGeneration(obj, expandoAndGeneration);
v = expandoAndGeneration->expando;
return v.isUndefined() ? nullptr : &v.toObject();
}
void ShadowingDOMProxyHandler::trace(JSTracer* trc, JSObject* proxy) const {
DOMProxyHandler::trace(trc, proxy);
MOZ_ASSERT(IsDOMProxy(proxy), "expected a DOM proxy object");
JS::Value v = js::GetProxyPrivate(proxy);
MOZ_ASSERT(!v.isObject(), "Should not have expando object directly!");
// The proxy's private slot is set when we allocate the proxy,
// so it cannot be |undefined|.
MOZ_ASSERT(!v.isUndefined());
auto* expandoAndGeneration =
static_cast<JS::ExpandoAndGeneration*>(v.toPrivate());
JS::TraceEdge(trc, &expandoAndGeneration->expando,
"Shadowing DOM proxy expando");
}
} // namespace mozilla::dom