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Bug 904701 - Implement prototype madness for ES6 generators. r=bhackett, r=jorendorff

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Add a Generator constructor, like the Function constructor.

Define the GeneratorFunctionPrototype, GeneratorFunction, and
GeneratorObjectPrototype meta-objects.

When cloning or creating a star generator, give it
GeneratorFunctionPrototype as its prototype.

Each star generator function has a ".prototype" property, which has
GeneratorObjectPrototype as its prototype.  That prototype does not have
a ".constructor" link.

If Function.prototype.toSource is called on a non-function, chain up to
Object.prototype.toSource instead.

Prototypes of generator objects are no longer made with
GeneratorObject::class_.  This allows us to elide some "null" checks
from bug 352885.  Instead calling a generator on a method now signals a
typeerror.

Make the "send" generator method a simple alias to "next".
This commit is contained in:
Andy Wingo
2013-08-23 11:07:10 -04:00
parent 4733a88992
commit 66cdba52f7
15 changed files with 490 additions and 156 deletions
Download Patch File Download Diff File Expand all files Collapse all files

203
js/src/jsiter.cpp
View File

@@ -958,7 +958,7 @@ const JSFunctionSpec ElementIteratorObject::methods[] = {
};
static bool
CloseGenerator(JSContext *cx, HandleObject genobj);
CloseLegacyGenerator(JSContext *cx, HandleObject genobj);
bool
js::ValueToIterator(JSContext *cx, unsigned flags, MutableHandleValue vp)
@@ -999,6 +999,30 @@ js::ValueToIterator(JSContext *cx, unsigned flags, MutableHandleValue vp)
return GetIterator(cx, obj, flags, vp);
}
bool
IsGenerator(HandleValue v)
{
return v.isObject() && v.toObject().is<GeneratorObject>();
}
static bool
IsLegacyGenerator(HandleObject obj)
{
if (!obj->is<GeneratorObject>())
return false;
JSGenerator *gen = obj->as<GeneratorObject>().getGenerator();
return gen->regs.fp()->script()->isLegacyGenerator();
}
bool
IsLegacyGenerator(HandleValue v)
{
if (!IsGenerator(v))
return false;
JSGenerator *gen = v.toObject().as<GeneratorObject>().getGenerator();
return gen->regs.fp()->script()->isLegacyGenerator();
}
bool
js::CloseIterator(JSContext *cx, HandleObject obj)
{
@@ -1020,9 +1044,8 @@ js::CloseIterator(JSContext *cx, HandleObject obj)
*/
ni->props_cursor = ni->props_array;
}
} else if (obj->is<GeneratorObject>()) {
// FIXME: Only close legacy generators.
return CloseGenerator(cx, obj);
} else if (IsLegacyGenerator(obj)) {
return CloseLegacyGenerator(cx, obj);
}
return true;
}
@@ -1477,15 +1500,25 @@ js_NewGenerator(JSContext *cx, const FrameRegs &stackRegs)
JS_ASSERT(stackfp->script()->isGenerator());
if (stackfp->script()->isStarGenerator()) {
JS_ReportErrorNumber(cx, js_GetErrorMessage, NULL, JSMSG_ES6_UNIMPLEMENTED);
return NULL;
}
Rooted<GlobalObject*> global(cx, &stackfp->global());
RootedObject obj(cx);
{
JSObject *proto = global->getOrCreateGeneratorPrototype(cx);
if (stackfp->script()->isStarGenerator()) {
RootedValue pval(cx);
RootedObject fun(cx, stackfp->fun());
// FIXME: This would be faster if we could avoid doing a lookup to get
// the prototype for the instance. Bug 906600.
if (!JSObject::getProperty(cx, fun, fun, cx->names().classPrototype, &pval))
return NULL;
JSObject *proto = pval.isObject() ? &pval.toObject() : NULL;
if (!proto) {
proto = global->getOrCreateStarGeneratorObjectPrototype(cx);
if (!proto)
return NULL;
}
obj = NewObjectWithGivenProto(cx, &GeneratorObject::class_, proto, global);
} else {
JS_ASSERT(stackfp->script()->isLegacyGenerator());
JSObject *proto = global->getOrCreateLegacyGeneratorObjectPrototype(cx);
if (!proto)
return NULL;
obj = NewObjectWithGivenProto(cx, &GeneratorObject::class_, proto, global);
@@ -1623,66 +1656,17 @@ SendToGenerator(JSContext *cx, JSGeneratorOp op, HandleObject obj,
}
static bool
CloseGenerator(JSContext *cx, HandleObject obj)
CloseLegacyGenerator(JSContext *cx, HandleObject obj)
{
JS_ASSERT(IsLegacyGenerator(obj));
JSGenerator *gen = obj->as<GeneratorObject>().getGenerator();
if (!gen) {
/* Generator prototype object. */
return true;
}
// FIXME: Assert that gen is a legacy generator.
if (gen->state == JSGEN_CLOSED)
return true;
return SendToGenerator(cx, JSGENOP_CLOSE, obj, gen, JS::UndefinedHandleValue);
}
JS_ALWAYS_INLINE bool
IsGenerator(HandleValue v)
{
return v.isObject() && v.toObject().is<GeneratorObject>();
}
JS_ALWAYS_INLINE bool
generator_send_impl(JSContext *cx, CallArgs args)
{
// FIXME: Change assertion to IsLegacyGenerator().
JS_ASSERT(IsGenerator(args.thisv()));
RootedObject thisObj(cx, &args.thisv().toObject());
JSGenerator *gen = thisObj->as<GeneratorObject>().getGenerator();
if (!gen || gen->state == JSGEN_CLOSED) {
/* This happens when obj is the generator prototype. See bug 352885. */
return js_ThrowStopIteration(cx);
}
if (gen->state == JSGEN_NEWBORN && args.hasDefined(0)) {
RootedValue val(cx, args[0]);
js_ReportValueError(cx, JSMSG_BAD_GENERATOR_SEND,
JSDVG_SEARCH_STACK, val, NullPtr());
return false;
}
// FIXME: next() takes the send value as an optional argument in ES6
// generator objects.
if (!SendToGenerator(cx, JSGENOP_SEND, thisObj, gen, args.get(0)))
return false;
args.rval().set(gen->fp->returnValue());
return true;
}
bool
generator_send(JSContext *cx, unsigned argc, Value *vp)
{
// FIXME: send() is only a method on legacy generator objects.
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsGenerator, generator_send_impl>(cx, args);
}
JS_ALWAYS_INLINE bool
generator_next_impl(JSContext *cx, CallArgs args)
{
@@ -1691,12 +1675,17 @@ generator_next_impl(JSContext *cx, CallArgs args)
RootedObject thisObj(cx, &args.thisv().toObject());
JSGenerator *gen = thisObj->as<GeneratorObject>().getGenerator();
if (!gen || gen->state == JSGEN_CLOSED) {
/* This happens when obj is the generator prototype. See bug 352885. */
if (gen->state == JSGEN_CLOSED)
return js_ThrowStopIteration(cx);
if (gen->state == JSGEN_NEWBORN && args.hasDefined(0)) {
RootedValue val(cx, args[0]);
js_ReportValueError(cx, JSMSG_BAD_GENERATOR_SEND,
JSDVG_SEARCH_STACK, val, NullPtr());
return false;
}
if (!SendToGenerator(cx, JSGENOP_NEXT, thisObj, gen, JS::UndefinedHandleValue))
if (!SendToGenerator(cx, JSGENOP_SEND, thisObj, gen, args.get(0)))
return false;
args.rval().set(gen->fp->returnValue());
@@ -1718,8 +1707,7 @@ generator_throw_impl(JSContext *cx, CallArgs args)
RootedObject thisObj(cx, &args.thisv().toObject());
JSGenerator *gen = thisObj->as<GeneratorObject>().getGenerator();
if (!gen || gen->state == JSGEN_CLOSED) {
/* This happens when obj is the generator prototype. See bug 352885. */
if (gen->state == JSGEN_CLOSED) {
cx->setPendingException(args.length() >= 1 ? args[0] : UndefinedValue());
return false;
}
@@ -1741,14 +1729,12 @@ generator_throw(JSContext *cx, unsigned argc, Value *vp)
JS_ALWAYS_INLINE bool
generator_close_impl(JSContext *cx, CallArgs args)
{
// FIXME: Change assertion to IsLegacyGenerator().
JS_ASSERT(IsGenerator(args.thisv()));
JS_ASSERT(IsLegacyGenerator(args.thisv()));
RootedObject thisObj(cx, &args.thisv().toObject());
JSGenerator *gen = thisObj->as<GeneratorObject>().getGenerator();
if (!gen || gen->state == JSGEN_CLOSED) {
/* This happens when obj is the generator prototype. See bug 352885. */
if (gen->state == JSGEN_CLOSED) {
args.rval().setUndefined();
return true;
}
@@ -1769,22 +1755,47 @@ generator_close_impl(JSContext *cx, CallArgs args)
bool
generator_close(JSContext *cx, unsigned argc, Value *vp)
{
// FIXME: close() is only a method on legacy generator objects.
CallArgs args = CallArgsFromVp(argc, vp);
return CallNonGenericMethod<IsGenerator, generator_close_impl>(cx, args);
return CallNonGenericMethod<IsLegacyGenerator, generator_close_impl>(cx, args);
}
#define JSPROP_ROPERM (JSPROP_READONLY | JSPROP_PERMANENT)
static const JSFunctionSpec generator_methods[] = {
static const JSFunctionSpec legacy_generator_methods[] = {
JS_FN("iterator", iterator_iterator, 0, 0),
JS_FN("next", generator_next, 0,JSPROP_ROPERM),
JS_FN("send", generator_send, 1,JSPROP_ROPERM),
JS_FN("next", generator_next, 1,JSPROP_ROPERM),
// Send is exactly the same as next.
JS_FN("send", generator_next, 1,JSPROP_ROPERM),
JS_FN("throw", generator_throw, 1,JSPROP_ROPERM),
JS_FN("close", generator_close, 0,JSPROP_ROPERM),
JS_FS_END
};
static const JSFunctionSpec star_generator_methods[] = {
JS_FN("iterator", iterator_iterator, 0, 0),
JS_FN("next", generator_next, 1,JSPROP_ROPERM),
JS_FN("throw", generator_throw, 1,JSPROP_ROPERM),
JS_FS_END
};
static JSObject*
NewObjectWithObjectPrototype(JSContext *cx, Handle<GlobalObject *> global)
{
JSObject *proto = global->getOrCreateObjectPrototype(cx);
if (!proto)
return NULL;
return NewObjectWithGivenProto(cx, &JSObject::class_, proto, global);
}
static JSObject*
NewObjectWithFunctionPrototype(JSContext *cx, Handle<GlobalObject *> global)
{
JSObject *proto = global->getOrCreateFunctionPrototype(cx);
if (!proto)
return NULL;
return NewObjectWithGivenProto(cx, &JSObject::class_, proto, global);
}
/* static */ bool
GlobalObject::initIteratorClasses(JSContext *cx, Handle<GlobalObject *> global)
{
@@ -1826,11 +1837,41 @@ GlobalObject::initIteratorClasses(JSContext *cx, Handle<GlobalObject *> global)
global->setReservedSlot(ELEMENT_ITERATOR_PROTO, ObjectValue(*proto));
}
if (global->getSlot(GENERATOR_PROTO).isUndefined()) {
proto = global->createBlankPrototype(cx, &GeneratorObject::class_);
if (!proto || !DefinePropertiesAndBrand(cx, proto, NULL, generator_methods))
if (global->getSlot(LEGACY_GENERATOR_OBJECT_PROTO).isUndefined()) {
proto = NewObjectWithObjectPrototype(cx, global);
if (!proto || !DefinePropertiesAndBrand(cx, proto, NULL, legacy_generator_methods))
return false;
global->setReservedSlot(GENERATOR_PROTO, ObjectValue(*proto));
global->setReservedSlot(LEGACY_GENERATOR_OBJECT_PROTO, ObjectValue(*proto));
}
if (global->getSlot(STAR_GENERATOR_OBJECT_PROTO).isUndefined()) {
RootedObject genObjectProto(cx, NewObjectWithObjectPrototype(cx, global));
if (!genObjectProto)
return false;
if (!DefinePropertiesAndBrand(cx, genObjectProto, NULL, star_generator_methods))
return false;
RootedObject genFunctionProto(cx, NewObjectWithFunctionPrototype(cx, global));
if (!genFunctionProto)
return false;
if (!LinkConstructorAndPrototype(cx, genFunctionProto, genObjectProto))
return false;
RootedValue function(cx, global->getConstructor(JSProto_Function));
if (!function.toObjectOrNull())
return false;
RootedAtom name(cx, cx->names().GeneratorFunction);
RootedObject genFunction(cx, NewFunctionWithProto(cx, NullPtr(), Generator, 1,
JSFunction::NATIVE_CTOR, global, name,
&function.toObject()));
if (!genFunction)
return false;
if (!LinkConstructorAndPrototype(cx, genFunction, genFunctionProto))
return false;
global->setSlot(STAR_GENERATOR_OBJECT_PROTO, ObjectValue(*genObjectProto));
global->setSlot(JSProto_GeneratorFunction, ObjectValue(*genFunction));
global->setSlot(JSProto_GeneratorFunction + JSProto_LIMIT, ObjectValue(*genFunctionProto));
}
if (global->getPrototype(JSProto_StopIteration).isUndefined()) {