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-rw-r--r--js/src/builtin/Symbol.cpp236
1 files changed, 236 insertions, 0 deletions
diff --git a/js/src/builtin/Symbol.cpp b/js/src/builtin/Symbol.cpp
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+++ b/js/src/builtin/Symbol.cpp
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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/. */
+
+#include "builtin/Symbol.h"
+#include "js/Symbol.h"
+
+#include "js/friend/ErrorMessages.h" // js::GetErrorMessage, JSMSG_*
+#include "js/PropertySpec.h"
+#include "util/StringBuffer.h"
+#include "vm/PlainObject.h" // js::PlainObject
+#include "vm/SymbolType.h"
+
+#include "vm/JSObject-inl.h"
+#include "vm/NativeObject-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(js_toString_str, toString, 0, 0),
+ JS_FN(js_valueOf_str, 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) {
+ HandleNativeObject nativeCtor = ctor.as<NativeObject>();
+
+ // Define the well-known symbol properties, such as Symbol.iterator.
+ ImmutablePropertyNamePtr* 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);
+}
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