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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, You can obtain one at http://mozilla.org/MPL/2.0/. */
/* Fundamental operations on objects. */
#ifndef vm_ObjectOperations_inl_h
#define vm_ObjectOperations_inl_h
#include "vm/ObjectOperations.h"
#include "mozilla/Assertions.h" // MOZ_ASSERT
#include "mozilla/Attributes.h" // MOZ_ALWAYS_INLINE
#include "mozilla/Likely.h" // MOZ_UNLIKELY
#include <stdint.h> // uint32_t
#include "jsapi.h" // JSPROP_ENUMERATE, JS::PropertyDescriptor
#include "js/Class.h" // js::{Delete,Get,Has}PropertyOp, JSMayResolveOp, JS::ObjectOpResult
#include "js/GCAPI.h" // JS::AutoSuppressGCAnalysis
#include "js/Id.h" // INT_TO_JSID, jsid, JSID_INT_MAX, SYMBOL_TO_JSID
#include "js/RootingAPI.h" // JS::Handle, JS::MutableHandle, JS::Rooted
#include "js/Value.h" // JS::ObjectValue, JS::Value
#include "proxy/Proxy.h" // js::Proxy
#include "vm/JSContext.h" // JSContext
#include "vm/JSObject.h" // JSObject
#include "vm/NativeObject.h" // js::NativeObject, js::Native{Get,Has,Set}Property, js::NativeGetPropertyNoGC, js::Qualified
#include "vm/ProxyObject.h" // js::ProxyObject
#include "vm/StringType.h" // js::NameToId
#include "vm/SymbolType.h" // JS::Symbol
#include "vm/JSAtom-inl.h" // js::IndexToId
namespace js {
// The functions below are the fundamental operations on objects. See the
// comment about "Standard internal methods" in jsapi.h.
/*
* ES6 [[GetPrototypeOf]]. Get obj's prototype, storing it in protop.
*
* If obj is definitely not a proxy, the infallible obj->getProto() can be used
* instead. See the comment on JSObject::getTaggedProto().
*/
inline bool GetPrototype(JSContext* cx, JS::Handle<JSObject*> obj,
JS::MutableHandle<JSObject*> protop) {
if (obj->hasDynamicPrototype()) {
MOZ_ASSERT(obj->is<ProxyObject>());
return Proxy::getPrototype(cx, obj, protop);
}
protop.set(obj->staticPrototype());
return true;
}
/*
* ES6 [[IsExtensible]]. Extensible objects can have new properties defined on
* them. Inextensible objects can't, and their [[Prototype]] slot is fixed as
* well.
*/
inline bool IsExtensible(JSContext* cx, JS::Handle<JSObject*> obj,
bool* extensible) {
if (obj->is<ProxyObject>()) {
MOZ_ASSERT(!cx->isHelperThreadContext());
return Proxy::isExtensible(cx, obj, extensible);
}
*extensible = obj->nonProxyIsExtensible();
// If the following assertion fails, there's somewhere else a missing
// call to shrinkCapacityToInitializedLength() which needs to be found and
// fixed.
MOZ_ASSERT_IF(obj->is<NativeObject>() && !*extensible,
obj->as<NativeObject>().getDenseInitializedLength() ==
obj->as<NativeObject>().getDenseCapacity());
return true;
}
/*
* ES6 [[Has]]. Set *foundp to true if `id in obj` (that is, if obj has an own
* or inherited property obj[id]), false otherwise.
*/
inline bool HasProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<jsid> id, bool* foundp) {
if (HasPropertyOp op = obj->getOpsHasProperty()) {
return op(cx, obj, id, foundp);
}
return NativeHasProperty(cx, obj.as<NativeObject>(), id, foundp);
}
inline bool HasProperty(JSContext* cx, JS::Handle<JSObject*> obj,
PropertyName* name, bool* foundp) {
JS::Rooted<jsid> id(cx, NameToId(name));
return HasProperty(cx, obj, id, foundp);
}
/*
* ES6 [[Get]]. Get the value of the property `obj[id]`, or undefined if no
* such property exists.
*
* Typically obj == receiver; if obj != receiver then the caller is most likely
* a proxy using GetProperty to finish a property get that started out as
* `receiver[id]`, and we've already searched the prototype chain up to `obj`.
*/
inline bool GetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JS::Value> receiver, JS::Handle<jsid> id,
JS::MutableHandle<JS::Value> vp) {
if (GetPropertyOp op = obj->getOpsGetProperty()) {
return op(cx, obj, receiver, id, vp);
}
return NativeGetProperty(cx, obj.as<NativeObject>(), receiver, id, vp);
}
inline bool GetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JS::Value> receiver, PropertyName* name,
JS::MutableHandle<JS::Value> vp) {
JS::Rooted<jsid> id(cx, NameToId(name));
return GetProperty(cx, obj, receiver, id, vp);
}
inline bool GetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JSObject*> receiver, JS::Handle<jsid> id,
JS::MutableHandle<JS::Value> vp) {
JS::Rooted<JS::Value> receiverValue(cx, JS::ObjectValue(*receiver));
return GetProperty(cx, obj, receiverValue, id, vp);
}
inline bool GetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JSObject*> receiver, PropertyName* name,
JS::MutableHandle<JS::Value> vp) {
JS::Rooted<JS::Value> receiverValue(cx, JS::ObjectValue(*receiver));
return GetProperty(cx, obj, receiverValue, name, vp);
}
inline bool GetElement(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JS::Value> receiver, uint32_t index,
JS::MutableHandle<JS::Value> vp) {
JS::Rooted<jsid> id(cx);
if (!IndexToId(cx, index, &id)) {
return false;
}
return GetProperty(cx, obj, receiver, id, vp);
}
inline bool GetElement(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<JSObject*> receiver, uint32_t index,
JS::MutableHandle<JS::Value> vp) {
JS::Rooted<JS::Value> receiverValue(cx, JS::ObjectValue(*receiver));
return GetElement(cx, obj, receiverValue, index, vp);
}
inline bool GetPropertyNoGC(JSContext* cx, JSObject* obj,
const JS::Value& receiver, jsid id, JS::Value* vp) {
if (obj->getOpsGetProperty()) {
return false;
}
return NativeGetPropertyNoGC(cx, &obj->as<NativeObject>(), receiver, id, vp);
}
inline bool GetPropertyNoGC(JSContext* cx, JSObject* obj,
const JS::Value& receiver, PropertyName* name,
JS::Value* vp) {
return GetPropertyNoGC(cx, obj, receiver, NameToId(name), vp);
}
inline bool GetElementNoGC(JSContext* cx, JSObject* obj,
const JS::Value& receiver, uint32_t index,
JS::Value* vp) {
if (obj->getOpsGetProperty()) {
return false;
}
if (index > JSID_INT_MAX) {
return false;
}
return GetPropertyNoGC(cx, obj, receiver, INT_TO_JSID(index), vp);
}
static MOZ_ALWAYS_INLINE bool ClassMayResolveId(const JSAtomState& names,
const JSClass* clasp, jsid id,
JSObject* maybeObj) {
MOZ_ASSERT_IF(maybeObj, maybeObj->getClass() == clasp);
if (!clasp->getResolve()) {
// Sanity check: we should only have a mayResolve hook if we have a
// resolve hook.
MOZ_ASSERT(!clasp->getMayResolve(),
"Class with mayResolve hook but no resolve hook");
return false;
}
if (JSMayResolveOp mayResolve = clasp->getMayResolve()) {
// Tell the analysis our mayResolve hooks won't trigger GC.
JS::AutoSuppressGCAnalysis nogc;
if (!mayResolve(names, id, maybeObj)) {
return false;
}
}
return true;
}
// Returns whether |obj| or an object on its proto chain may have an interesting
// symbol property (see JSObject::hasInterestingSymbolProperty). If it returns
// true, *holder is set to the object that may have this property.
MOZ_ALWAYS_INLINE bool MaybeHasInterestingSymbolProperty(
JSContext* cx, JSObject* obj, JS::Symbol* symbol,
JSObject** holder /* = nullptr */) {
MOZ_ASSERT(symbol->isInterestingSymbol());
jsid id = SYMBOL_TO_JSID(symbol);
do {
if (obj->maybeHasInterestingSymbolProperty() ||
MOZ_UNLIKELY(
ClassMayResolveId(cx->names(), obj->getClass(), id, obj))) {
if (holder) {
*holder = obj;
}
return true;
}
obj = obj->staticPrototype();
} while (obj);
return false;
}
// Like GetProperty but optimized for interesting symbol properties like
// @@toStringTag.
MOZ_ALWAYS_INLINE bool GetInterestingSymbolProperty(
JSContext* cx, JS::Handle<JSObject*> obj, JS::Symbol* sym,
JS::MutableHandle<JS::Value> vp) {
JSObject* holder;
if (!MaybeHasInterestingSymbolProperty(cx, obj, sym, &holder)) {
#ifdef DEBUG
JS::Rooted<JS::Value> receiver(cx, JS::ObjectValue(*obj));
JS::Rooted<jsid> id(cx, SYMBOL_TO_JSID(sym));
if (!GetProperty(cx, obj, receiver, id, vp)) {
return false;
}
MOZ_ASSERT(vp.isUndefined());
#endif
vp.setUndefined();
return true;
}
JS::Rooted<JSObject*> holderRoot(cx, holder);
JS::Rooted<JS::Value> receiver(cx, JS::ObjectValue(*obj));
JS::Rooted<jsid> id(cx, SYMBOL_TO_JSID(sym));
return GetProperty(cx, holderRoot, receiver, id, vp);
}
/*
* ES6 [[Set]]. Carry out the assignment `obj[id] = v`.
*
* The `receiver` argument has to do with how [[Set]] interacts with the
* prototype chain and proxies. It's hard to explain and ES6 doesn't really
* try. Long story short, if you just want bog-standard assignment, pass
* `ObjectValue(*obj)` as receiver. Or better, use one of the signatures that
* doesn't have a receiver parameter.
*
* Callers pass obj != receiver e.g. when a proxy is involved, obj is the
* proxy's target, and the proxy is using SetProperty to finish an assignment
* that started out as `receiver[id] = v`, by delegating it to obj.
*/
inline bool SetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<jsid> id, JS::Handle<JS::Value> v,
JS::Handle<JS::Value> receiver,
JS::ObjectOpResult& result) {
if (obj->getOpsSetProperty()) {
return JSObject::nonNativeSetProperty(cx, obj, id, v, receiver, result);
}
return NativeSetProperty<Qualified>(cx, obj.as<NativeObject>(), id, v,
receiver, result);
}
inline bool SetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<jsid> id, JS::Handle<JS::Value> v) {
JS::Rooted<JS::Value> receiver(cx, JS::ObjectValue(*obj));
JS::ObjectOpResult result;
return SetProperty(cx, obj, id, v, receiver, result) &&
result.checkStrict(cx, obj, id);
}
inline bool SetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
PropertyName* name, JS::Handle<JS::Value> v,
JS::Handle<JS::Value> receiver,
JS::ObjectOpResult& result) {
JS::Rooted<jsid> id(cx, NameToId(name));
return SetProperty(cx, obj, id, v, receiver, result);
}
inline bool SetProperty(JSContext* cx, JS::Handle<JSObject*> obj,
PropertyName* name, JS::Handle<JS::Value> v) {
JS::Rooted<jsid> id(cx, NameToId(name));
JS::Rooted<JS::Value> receiver(cx, JS::ObjectValue(*obj));
JS::ObjectOpResult result;
return SetProperty(cx, obj, id, v, receiver, result) &&
result.checkStrict(cx, obj, id);
}
inline bool SetElement(JSContext* cx, JS::Handle<JSObject*> obj, uint32_t index,
JS::Handle<JS::Value> v, JS::Handle<JS::Value> receiver,
JS::ObjectOpResult& result) {
if (obj->getOpsSetProperty()) {
return JSObject::nonNativeSetElement(cx, obj, index, v, receiver, result);
}
return NativeSetElement(cx, obj.as<NativeObject>(), index, v, receiver,
result);
}
/*
* ES6 draft rev 31 (15 Jan 2015) 7.3.3 Put (O, P, V, Throw), except that on
* success, the spec says this is supposed to return a boolean value, which we
* don't bother doing.
*/
inline bool PutProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<jsid> id, JS::Handle<JS::Value> v,
bool strict) {
JS::Rooted<JS::Value> receiver(cx, JS::ObjectValue(*obj));
JS::ObjectOpResult result;
return SetProperty(cx, obj, id, v, receiver, result) &&
result.checkStrictModeError(cx, obj, id, strict);
}
/*
* ES6 [[Delete]]. Equivalent to the JS code `delete obj[id]`.
*/
inline bool DeleteProperty(JSContext* cx, JS::Handle<JSObject*> obj,
JS::Handle<jsid> id, JS::ObjectOpResult& result) {
if (DeletePropertyOp op = obj->getOpsDeleteProperty()) {
return op(cx, obj, id, result);
}
return NativeDeleteProperty(cx, obj.as<NativeObject>(), id, result);
}
inline bool DeleteElement(JSContext* cx, JS::Handle<JSObject*> obj,
uint32_t index, JS::ObjectOpResult& result) {
JS::Rooted<jsid> id(cx);
if (!IndexToId(cx, index, &id)) {
return false;
}
return DeleteProperty(cx, obj, id, result);
}
} /* namespace js */
#endif /* vm_ObjectOperations_inl_h */