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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
#include "builtin/Symbol.h"
#include "js/Symbol.h"
#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_*
#include "js/PropertySpec.h"
#include "vm/PlainObject.h" // js::PlainObject
#include "vm/SymbolType.h"
#include "vm/JSObject-inl.h"
using namespace js;
const JSClass SymbolObject::class_ = {
"Symbol",
JSCLASS_HAS_RESERVED_SLOTS(RESERVED_SLOTS) |
JSCLASS_HAS_CACHED_PROTO(JSProto_Symbol),
JS_NULL_CLASS_OPS, &SymbolObject::classSpec_};
// This uses PlainObject::class_ because: "The Symbol prototype object is an
// ordinary object. It is not a Symbol instance and does not have a
// [[SymbolData]] internal slot." (ES6 rev 24, 19.4.3)
const JSClass& SymbolObject::protoClass_ = PlainObject::class_;
SymbolObject* SymbolObject::create(JSContext* cx, JS::HandleSymbol symbol) {
SymbolObject* obj = NewBuiltinClassInstance<SymbolObject>(cx);
if (!obj) {
return nullptr;
}
obj->setPrimitiveValue(symbol);
return obj;
}
const JSPropertySpec SymbolObject::properties[] = {
JS_PSG("description", descriptionGetter, 0),
JS_STRING_SYM_PS(toStringTag, "Symbol", JSPROP_READONLY), JS_PS_END};
const JSFunctionSpec SymbolObject::methods[] = {
JS_FN("toString", toString, 0, 0), JS_FN("valueOf", valueOf, 0, 0),
JS_SYM_FN(toPrimitive, toPrimitive, 1, JSPROP_READONLY), JS_FS_END};
const JSFunctionSpec SymbolObject::staticMethods[] = {
JS_FN("for", for_, 1, 0), JS_FN("keyFor", keyFor, 1, 0), JS_FS_END};
static bool SymbolClassFinish(JSContext* cx, HandleObject ctor,
HandleObject proto) {
Handle<NativeObject*> nativeCtor = ctor.as<NativeObject>();
// Define the well-known symbol properties, such as Symbol.iterator.
ImmutableTenuredPtr<PropertyName*>* names =
cx->names().wellKnownSymbolNames();
RootedValue value(cx);
unsigned attrs = JSPROP_READONLY | JSPROP_PERMANENT;
WellKnownSymbols* wks = cx->runtime()->wellKnownSymbols;
for (size_t i = 0; i < JS::WellKnownSymbolLimit; i++) {
value.setSymbol(wks->get(i));
if (!NativeDefineDataProperty(cx, nativeCtor, names[i], value, attrs)) {
return false;
}
}
return true;
}
const ClassSpec SymbolObject::classSpec_ = {
GenericCreateConstructor<SymbolObject::construct, 0,
gc::AllocKind::FUNCTION>,
GenericCreatePrototype<SymbolObject>,
staticMethods,
nullptr,
methods,
properties,
SymbolClassFinish};
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.1.1 Symbol ( [ description ] )
bool SymbolObject::construct(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1.
if (args.isConstructing()) {
JS_ReportErrorNumberASCII(cx, GetErrorMessage, nullptr,
JSMSG_NOT_CONSTRUCTOR, "Symbol");
return false;
}
// Steps 2-3.
RootedString desc(cx);
if (!args.get(0).isUndefined()) {
desc = ToString(cx, args.get(0));
if (!desc) {
return false;
}
}
// Step 4.
JS::Symbol* symbol = JS::Symbol::new_(cx, JS::SymbolCode::UniqueSymbol, desc);
if (!symbol) {
return false;
}
args.rval().setSymbol(symbol);
return true;
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.2.2 Symbol.for ( key )
bool SymbolObject::for_(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1.
RootedString stringKey(cx, ToString(cx, args.get(0)));
if (!stringKey) {
return false;
}
// Steps 2-6.
JS::Symbol* symbol = JS::Symbol::for_(cx, stringKey);
if (!symbol) {
return false;
}
args.rval().setSymbol(symbol);
return true;
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.2.6 Symbol.keyFor ( sym )
bool SymbolObject::keyFor(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// Step 1.
HandleValue arg = args.get(0);
if (!arg.isSymbol()) {
ReportValueError(cx, JSMSG_UNEXPECTED_TYPE, JSDVG_SEARCH_STACK, arg,
nullptr, "not a symbol");
return false;
}
// Step 2.
if (arg.toSymbol()->code() == JS::SymbolCode::InSymbolRegistry) {
#ifdef DEBUG
RootedString desc(cx, arg.toSymbol()->description());
MOZ_ASSERT(JS::Symbol::for_(cx, desc) == arg.toSymbol());
#endif
args.rval().setString(arg.toSymbol()->description());
return true;
}
// Step 3: omitted.
// Step 4.
args.rval().setUndefined();
return true;
}
static MOZ_ALWAYS_INLINE bool IsSymbol(HandleValue v) {
return v.isSymbol() || (v.isObject() && v.toObject().is<SymbolObject>());
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.3 Properties of the Symbol Prototype Object, thisSymbolValue.
static MOZ_ALWAYS_INLINE JS::Symbol* ThisSymbolValue(HandleValue val) {
// Step 3, the error case, is handled by CallNonGenericMethod.
MOZ_ASSERT(IsSymbol(val));
// Step 1.
if (val.isSymbol()) {
return val.toSymbol();
}
// Step 2.
return val.toObject().as<SymbolObject>().unbox();
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.3.3 Symbol.prototype.toString ( )
bool SymbolObject::toString_impl(JSContext* cx, const CallArgs& args) {
// Step 1.
JS::Symbol* sym = ThisSymbolValue(args.thisv());
// Step 2.
return SymbolDescriptiveString(cx, sym, args.rval());
}
bool SymbolObject::toString(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsSymbol, toString_impl>(cx, args);
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.3.4 Symbol.prototype.valueOf ( )
bool SymbolObject::valueOf_impl(JSContext* cx, const CallArgs& args) {
// Step 1.
args.rval().setSymbol(ThisSymbolValue(args.thisv()));
return true;
}
bool SymbolObject::valueOf(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsSymbol, valueOf_impl>(cx, args);
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.3.5 Symbol.prototype [ @@toPrimitive ] ( hint )
bool SymbolObject::toPrimitive(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
// The specification gives exactly the same algorithm for @@toPrimitive as
// for valueOf, so reuse the valueOf implementation.
return CallNonGenericMethod<IsSymbol, valueOf_impl>(cx, args);
}
// ES2020 draft rev ecb4178012d6b4d9abc13fcbd45f5c6394b832ce
// 19.4.3.2 get Symbol.prototype.description
bool SymbolObject::descriptionGetter_impl(JSContext* cx, const CallArgs& args) {
// Steps 1-2.
JS::Symbol* sym = ThisSymbolValue(args.thisv());
// Step 3.
// Return the symbol's description if present, otherwise return undefined.
if (JSString* str = sym->description()) {
args.rval().setString(str);
} else {
args.rval().setUndefined();
}
return true;
}
bool SymbolObject::descriptionGetter(JSContext* cx, unsigned argc, Value* vp) {
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsSymbol, descriptionGetter_impl>(cx, args);
}