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// Copyright (C) 2018 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant
#include <qv4generatorobject_p.h>
#include <qv4symbol_p.h>
#include <qv4iterator_p.h>
#include <qv4jscall_p.h>
#include <qv4vme_moth_p.h>
using namespace QV4;
DEFINE_OBJECT_VTABLE(GeneratorFunctionCtor);
DEFINE_OBJECT_VTABLE(GeneratorFunction);
DEFINE_OBJECT_VTABLE(GeneratorObject);
void Heap::GeneratorFunctionCtor::init(QV4::ExecutionEngine *engine)
{
Heap::FunctionObject::init(engine, QStringLiteral("GeneratorFunction"));
}
ReturnedValue GeneratorFunctionCtor::virtualCallAsConstructor(const FunctionObject *f, const Value *argv, int argc, const Value *newTarget)
{
ExecutionEngine *engine = f->engine();
QQmlRefPointer<ExecutableCompilationUnit> compilationUnit = parse(engine, argv, argc, Type_Generator);
if (engine->hasException)
return Encode::undefined();
Function *vmf = compilationUnit->rootFunction();
ExecutionContext *global = engine->scriptContext();
ReturnedValue o = Encode(GeneratorFunction::create(global, vmf));
if (!newTarget)
return o;
Scope scope(engine);
ScopedObject obj(scope, o);
obj->setProtoFromNewTarget(newTarget);
return obj->asReturnedValue();
}
// 15.3.1: This is equivalent to new Function(...)
ReturnedValue GeneratorFunctionCtor::virtualCall(const FunctionObject *f, const Value *, const Value *argv, int argc)
{
return virtualCallAsConstructor(f, argv, argc, f);
}
Heap::FunctionObject *GeneratorFunction::create(ExecutionContext *context, Function *function)
{
Scope scope(context);
Scoped<GeneratorFunction> g(scope, context->engine()->memoryManager->allocate<GeneratorFunction>(context, function));
ScopedObject proto(scope, scope.engine->newObject());
proto->setPrototypeOf(scope.engine->generatorPrototype());
g->defineDefaultProperty(scope.engine->id_prototype(), proto, Attr_NotConfigurable|Attr_NotEnumerable);
g->setPrototypeOf(ScopedObject(scope, scope.engine->generatorFunctionCtor()->get(scope.engine->id_prototype())));
return g->d();
}
// The interpreter writes to the generator's frame without write barrier. While the generator is
// executing, the frame is marked as part of the stack. Once it's suspended, we need to mark it
// explicitly.
static void markSuspendedFrame(ExecutionEngine *engine, const JSTypesStackFrame *frame)
{
WriteBarrier::markCustom(engine,
[frame](MarkStack *markStack) { frame->markJSFrame(markStack); });
}
ReturnedValue GeneratorFunction::virtualCall(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc)
{
const GeneratorFunction *gf = static_cast<const GeneratorFunction *>(f);
Function *function = gf->function();
ExecutionEngine *engine = gf->engine();
Scope scope(engine);
CHECK_STACK_LIMITS(engine)
Scoped<GeneratorObject> g(scope, engine->memoryManager->allocManaged<GeneratorObject>(engine->classes[EngineBase::Class_GeneratorObject]));
g->setPrototypeOf(ScopedObject(scope, gf->get(engine->id_prototype())));
// We need to set up a separate JSFrame for the generator, as it's being re-entered
Heap::GeneratorObject *gp = g->d();
gp->values.set(engine, engine->newArrayObject(argc));
gp->jsFrame.set(engine, engine->newArrayObject(
JSTypesStackFrame::requiredJSStackFrameSize(function)));
// copy original arguments
for (int i = 0; i < argc; i++)
gp->values->arrayData->setArrayData(engine, i, argv[i]);
gp->cppFrame.init(function, gp->values->arrayData->values.values, argc);
gp->cppFrame.setupJSFrame(gp->jsFrame->arrayData->values.values, *gf, gf->scope(),
thisObject ? *thisObject : Value::undefinedValue(),
Value::undefinedValue());
gp->cppFrame.push(engine);
Moth::VME::interpret(&gp->cppFrame, engine, function->codeData);
markSuspendedFrame(engine, &gp->cppFrame);
gp->state = GeneratorState::SuspendedStart;
gp->cppFrame.pop(engine);
return g->asReturnedValue();
}
void Heap::GeneratorPrototype::init()
{
Heap::FunctionObject::init();
}
void GeneratorPrototype::init(ExecutionEngine *engine, Object *ctor)
{
Scope scope(engine);
ScopedValue v(scope);
Scoped<InternalClass> ic(scope, engine->newInternalClass(
Object::staticVTable(), engine->functionPrototype()));
ScopedObject ctorProto(scope, engine->newObject(ic->d()));
ctor->defineReadonlyConfigurableProperty(engine->id_length(), Value::fromInt32(1));
ctor->defineReadonlyProperty(engine->id_prototype(), ctorProto);
ctorProto->defineDefaultProperty(QStringLiteral("constructor"), (v = ctor), Attr_ReadOnly_ButConfigurable);
ctorProto->defineDefaultProperty(engine->symbol_toStringTag(), (v = engine->newIdentifier(QStringLiteral("GeneratorFunction"))), Attr_ReadOnly_ButConfigurable);
ctorProto->defineDefaultProperty(engine->id_prototype(), (v = this), Attr_ReadOnly_ButConfigurable);
setPrototypeOf(engine->iteratorPrototype());
defineDefaultProperty(QStringLiteral("constructor"), ctorProto, Attr_ReadOnly_ButConfigurable);
defineDefaultProperty(QStringLiteral("next"), method_next, 1);
defineDefaultProperty(QStringLiteral("return"), method_return, 1);
defineDefaultProperty(QStringLiteral("throw"), method_throw, 1);
defineDefaultProperty(engine->symbol_toStringTag(), (v = engine->newString(QStringLiteral("Generator"))), Attr_ReadOnly_ButConfigurable);
}
ReturnedValue GeneratorPrototype::method_next(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc)
{
ExecutionEngine *engine = f->engine();
const GeneratorObject *g = thisObject->as<GeneratorObject>();
if (!g || g->d()->state == GeneratorState::Executing)
return engine->throwTypeError();
Heap::GeneratorObject *gp = g->d();
if (gp->state == GeneratorState::Completed)
return IteratorPrototype::createIterResultObject(engine, Value::undefinedValue(), true);
return g->resume(engine, argc ? argv[0] : Value::undefinedValue(), {});
}
ReturnedValue GeneratorPrototype::method_return(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc)
{
ExecutionEngine *engine = f->engine();
const GeneratorObject *g = thisObject->as<GeneratorObject>();
if (!g || g->d()->state == GeneratorState::Executing)
return engine->throwTypeError();
Heap::GeneratorObject *gp = g->d();
if (gp->state == GeneratorState::SuspendedStart)
gp->state = GeneratorState::Completed;
if (gp->state == GeneratorState::Completed)
return IteratorPrototype::createIterResultObject(engine, argc ? argv[0] : Value::undefinedValue(), true);
return g->resume(engine, argc ? argv[0] : Value::undefinedValue(), Value::emptyValue());
}
ReturnedValue GeneratorPrototype::method_throw(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc)
{
ExecutionEngine *engine = f->engine();
const GeneratorObject *g = thisObject->as<GeneratorObject>();
if (!g || g->d()->state == GeneratorState::Executing)
return engine->throwTypeError();
Heap::GeneratorObject *gp = g->d();
if (gp->state == GeneratorState::SuspendedStart || gp->state == GeneratorState::Completed) {
gp->state = GeneratorState::Completed;
engine->throwError(argc ? argv[0] : Value::undefinedValue());
return Encode::undefined();
}
return g->resume(engine, Value::undefinedValue(), argc ? argv[0] : Value::undefinedValue());
}
ReturnedValue GeneratorObject::resume(ExecutionEngine *engine, const Value &arg, std::optional<Value> exception) const
{
Scope scope(engine);
CHECK_STACK_LIMITS(scope.engine)
Heap::GeneratorObject *gp = d();
gp->state = GeneratorState::Executing;
gp->cppFrame.setParentFrame(engine->currentStackFrame);
engine->currentStackFrame = &gp->cppFrame;
Q_ASSERT(gp->cppFrame.yield() != nullptr);
const char *code = gp->cppFrame.yield();
gp->cppFrame.setYield(nullptr);
gp->cppFrame.jsFrame->accumulator = arg;
gp->cppFrame.setYieldIsIterator(false);
// A value to be thrown will be passed in by `method_throw` or
// `method_return` when they need to resume the generator.
// For `method_throw` this will be the value that was passed to
// `throw` itself.
// For `method_return` this will be an `emptyValue`.
// The empty value will be used as a signal that `return` was
// called and managed in the execution of a `Resume` instruction
// during `interpret`.
if (exception)
engine->throwError(*exception);
ScopedValue result(scope, Moth::VME::interpret(&gp->cppFrame, engine, code));
engine->currentStackFrame = gp->cppFrame.parentFrame();
markSuspendedFrame(engine, &gp->cppFrame);
bool done = (gp->cppFrame.yield() == nullptr);
gp->state = done ? GeneratorState::Completed : GeneratorState::SuspendedYield;
if (engine->hasException)
return Encode::undefined();
if (gp->cppFrame.yieldIsIterator())
return result->asReturnedValue();
return IteratorPrototype::createIterResultObject(engine, result, done);
}
DEFINE_OBJECT_VTABLE(MemberGeneratorFunction);
Heap::FunctionObject *MemberGeneratorFunction::create(ExecutionContext *context, Function *function, Object *homeObject, String *name)
{
Scope scope(context);
Scoped<MemberGeneratorFunction> g(scope, context->engine()->memoryManager->allocate<MemberGeneratorFunction>(context, function, name));
g->d()->homeObject.set(scope.engine, homeObject->d());
ScopedObject proto(scope, scope.engine->newObject());
proto->setPrototypeOf(scope.engine->generatorPrototype());
g->defineDefaultProperty(scope.engine->id_prototype(), proto, Attr_NotConfigurable|Attr_NotEnumerable);
g->setPrototypeOf(ScopedObject(scope, scope.engine->generatorFunctionCtor()->get(scope.engine->id_prototype())));
return g->d();
}
ReturnedValue MemberGeneratorFunction::virtualCall(const FunctionObject *f, const Value *thisObject, const Value *argv, int argc)
{
return GeneratorFunction::virtualCall(f, thisObject, argv, argc);
}