/*
* Copyright (c) 2021-2023, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Bytecode/CommonImplementations.h>
#include <LibJS/Bytecode/Interpreter.h>
#include <LibJS/Bytecode/Op.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/DeclarativeEnvironment.h>
#include <LibJS/Runtime/ECMAScriptFunctionObject.h>
#include <LibJS/Runtime/FunctionEnvironment.h>
#include <LibJS/Runtime/GlobalEnvironment.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/ObjectEnvironment.h>
#include <LibJS/Runtime/RegExpObject.h>
namespace JS::Bytecode {
ThrowCompletionOr<NonnullGCPtr<Object>> base_object_for_get(Bytecode::Interpreter& interpreter, Value base_value)
{
auto& vm = interpreter.vm();
if (base_value.is_object())
return base_value.as_object();
// OPTIMIZATION: For various primitives we can avoid actually creating a new object for them.
if (base_value.is_string())
return vm.current_realm()->intrinsics().string_prototype();
if (base_value.is_number())
return vm.current_realm()->intrinsics().number_prototype();
if (base_value.is_boolean())
return vm.current_realm()->intrinsics().boolean_prototype();
return base_value.to_object(vm);
}
ThrowCompletionOr<Value> get_by_id(Bytecode::Interpreter& interpreter, IdentifierTableIndex property, Value base_value, Value this_value, u32 cache_index)
{
auto& vm = interpreter.vm();
auto const& name = interpreter.current_executable().get_identifier(property);
auto& cache = interpreter.current_executable().property_lookup_caches[cache_index];
if (base_value.is_string()) {
auto string_value = TRY(base_value.as_string().get(vm, name));
if (string_value.has_value())
return *string_value;
}
auto base_obj = TRY(base_object_for_get(interpreter, base_value));
// OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
// NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
auto& shape = base_obj->shape();
if (&shape == cache.shape
&& (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
return base_obj->get_direct(cache.property_offset.value());
}
CacheablePropertyMetadata cacheable_metadata;
auto value = TRY(base_obj->internal_get(name, this_value, &cacheable_metadata));
if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
cache.shape = shape;
cache.property_offset = cacheable_metadata.property_offset.value();
cache.unique_shape_serial_number = shape.unique_shape_serial_number();
}
return value;
}
ThrowCompletionOr<Value> get_by_value(Bytecode::Interpreter& interpreter, Value base_value, Value property_key_value)
{
auto& vm = interpreter.vm();
auto object = TRY(base_object_for_get(interpreter, base_value));
// OPTIMIZATION: Fast path for simple Int32 indexes in array-like objects.
if (property_key_value.is_int32()
&& property_key_value.as_i32() >= 0
&& !object->may_interfere_with_indexed_property_access()
&& object->indexed_properties().has_index(property_key_value.as_i32())) {
auto value = object->indexed_properties().get(property_key_value.as_i32())->value;
if (!value.is_accessor())
return value;
}
auto property_key = TRY(property_key_value.to_property_key(vm));
if (base_value.is_string()) {
auto string_value = TRY(base_value.as_string().get(vm, property_key));
if (string_value.has_value())
return *string_value;
}
return TRY(object->internal_get(property_key, base_value));
}
ThrowCompletionOr<Value> get_global(Bytecode::Interpreter& interpreter, IdentifierTableIndex identifier, u32 cache_index)
{
auto& vm = interpreter.vm();
auto& realm = *vm.current_realm();
auto& cache = interpreter.current_executable().global_variable_caches[cache_index];
auto& binding_object = realm.global_environment().object_record().binding_object();
auto& declarative_record = realm.global_environment().declarative_record();
// OPTIMIZATION: If the shape of the object hasn't changed, we can use the cached property offset.
// NOTE: Unique shapes don't change identity, so we compare their serial numbers instead.
auto& shape = binding_object.shape();
if (cache.environment_serial_number == declarative_record.environment_serial_number()
&& &shape == cache.shape
&& (!shape.is_unique() || shape.unique_shape_serial_number() == cache.unique_shape_serial_number)) {
return binding_object.get_direct(cache.property_offset.value());
}
cache.environment_serial_number = declarative_record.environment_serial_number();
auto const& name = interpreter.current_executable().get_identifier(identifier);
if (vm.running_execution_context().script_or_module.has<NonnullGCPtr<Module>>()) {
// NOTE: GetGlobal is used to access variables stored in the module environment and global environment.
// The module environment is checked first since it precedes the global environment in the environment chain.
auto& module_environment = *vm.running_execution_context().script_or_module.get<NonnullGCPtr<Module>>()->environment();
if (TRY(module_environment.has_binding(name))) {
// TODO: Cache offset of binding value
return TRY(module_environment.get_binding_value(vm, name, vm.in_strict_mode()));
}
}
if (TRY(declarative_record.has_binding(name))) {
// TODO: Cache offset of binding value
return TRY(declarative_record.get_binding_value(vm, name, vm.in_strict_mode()));
}
if (TRY(binding_object.has_property(name))) {
CacheablePropertyMetadata cacheable_metadata;
auto value = TRY(binding_object.internal_get(name, js_undefined(), &cacheable_metadata));
if (cacheable_metadata.type == CacheablePropertyMetadata::Type::OwnProperty) {
cache.shape = shape;
cache.property_offset = cacheable_metadata.property_offset.value();
cache.unique_shape_serial_number = shape.unique_shape_serial_number();
}
return value;
}
return vm.throw_completion<ReferenceError>(ErrorType::UnknownIdentifier, name);
}
ThrowCompletionOr<void> put_by_property_key(VM& vm, Value base, Value this_value, Value value, PropertyKey name, Op::PropertyKind kind)
{
auto object = TRY(base.to_object(vm));
if (kind == Op::PropertyKind::Getter || kind == Op::PropertyKind::Setter) {
// The generator should only pass us functions for getters and setters.
VERIFY(value.is_function());
}
switch (kind) {
case Op::PropertyKind::Getter: {
auto& function = value.as_function();
if (function.name().is_empty() && is<ECMAScriptFunctionObject>(function))
static_cast<ECMAScriptFunctionObject*>(&function)->set_name(DeprecatedString::formatted("get {}", name));
object->define_direct_accessor(name, &function, nullptr, Attribute::Configurable | Attribute::Enumerable);
break;
}
case Op::PropertyKind::Setter: {
auto& function = value.as_function();
if (function.name().is_empty() && is<ECMAScriptFunctionObject>(function))
static_cast<ECMAScriptFunctionObject*>(&function)->set_name(DeprecatedString::formatted("set {}", name));
object->define_direct_accessor(name, nullptr, &function, Attribute::Configurable | Attribute::Enumerable);
break;
}
case Op::PropertyKind::KeyValue: {
bool succeeded = TRY(object->internal_set(name, value, this_value));
if (!succeeded && vm.in_strict_mode())
return vm.throw_completion<TypeError>(ErrorType::ReferenceNullishSetProperty, name, base.to_string_without_side_effects());
break;
}
case Op::PropertyKind::DirectKeyValue:
object->define_direct_property(name, value, Attribute::Enumerable | Attribute::Writable | Attribute::Configurable);
break;
case Op::PropertyKind::Spread:
TRY(object->copy_data_properties(vm, value, {}));
break;
case Op::PropertyKind::ProtoSetter:
if (value.is_object() || value.is_null())
MUST(object->internal_set_prototype_of(value.is_object() ? &value.as_object() : nullptr));
break;
}
return {};
}
ThrowCompletionOr<Value> perform_call(Interpreter& interpreter, Value this_value, Op::CallType call_type, Value callee, MarkedVector<Value> argument_values)
{
auto& vm = interpreter.vm();
auto& function = callee.as_function();
Value return_value;
if (call_type == Op::CallType::DirectEval) {
if (callee == interpreter.realm().intrinsics().eval_function())
return_value = TRY(perform_eval(vm, !argument_values.is_empty() ? argument_values[0].value_or(JS::js_undefined()) : js_undefined(), vm.in_strict_mode() ? CallerMode::Strict : CallerMode::NonStrict, EvalMode::Direct));
else
return_value = TRY(JS::call(vm, function, this_value, move(argument_values)));
} else if (call_type == Op::CallType::Call)
return_value = TRY(JS::call(vm, function, this_value, move(argument_values)));
else
return_value = TRY(construct(vm, function, move(argument_values)));
return return_value;
}
static Completion throw_type_error_for_callee(Bytecode::Interpreter& interpreter, Value callee, StringView callee_type, Optional<StringTableIndex> const& expression_string)
{
auto& vm = interpreter.vm();
if (expression_string.has_value())
return vm.throw_completion<TypeError>(ErrorType::IsNotAEvaluatedFrom, callee.to_string_without_side_effects(), callee_type, interpreter.current_executable().get_string(expression_string->value()));
return vm.throw_completion<TypeError>(ErrorType::IsNotA, callee.to_string_without_side_effects(), callee_type);
}
ThrowCompletionOr<void> throw_if_needed_for_call(Interpreter& interpreter, Value callee, Op::CallType call_type, Optional<StringTableIndex> const& expression_string)
{
if (call_type == Op::CallType::Call && !callee.is_function())
return throw_type_error_for_callee(interpreter, callee, "function"sv, expression_string);
if (call_type == Op::CallType::Construct && !callee.is_constructor())
return throw_type_error_for_callee(interpreter, callee, "constructor"sv, expression_string);
return {};
}
ThrowCompletionOr<Value> typeof_variable(VM& vm, DeprecatedFlyString const& string)
{
// 1. Let val be the result of evaluating UnaryExpression.
auto reference = TRY(vm.resolve_binding(string));
// 2. If val is a Reference Record, then
// a. If IsUnresolvableReference(val) is true, return "undefined".
if (reference.is_unresolvable())
return PrimitiveString::create(vm, "undefined"_string);
// 3. Set val to ? GetValue(val).
auto value = TRY(reference.get_value(vm));
// 4. NOTE: This step is replaced in section B.3.6.3.
// 5. Return a String according to Table 41.
return PrimitiveString::create(vm, value.typeof());
}
ThrowCompletionOr<void> set_variable(
VM& vm,
DeprecatedFlyString const& name,
Value value,
Op::EnvironmentMode mode,
Op::SetVariable::InitializationMode initialization_mode)
{
auto environment = mode == Op::EnvironmentMode::Lexical ? vm.running_execution_context().lexical_environment : vm.running_execution_context().variable_environment;
auto reference = TRY(vm.resolve_binding(name, environment));
switch (initialization_mode) {
case Op::SetVariable::InitializationMode::Initialize:
TRY(reference.initialize_referenced_binding(vm, value));
break;
case Op::SetVariable::InitializationMode::Set:
TRY(reference.put_value(vm, value));
break;
}
return {};
}
Value new_function(VM& vm, FunctionExpression const& function_node, Optional<IdentifierTableIndex> const& lhs_name, Optional<Register> const& home_object)
{
Value value;
if (!function_node.has_name()) {
DeprecatedFlyString name = {};
if (lhs_name.has_value())
name = vm.bytecode_interpreter().current_executable().get_identifier(lhs_name.value());
value = function_node.instantiate_ordinary_function_expression(vm, name);
} else {
value = ECMAScriptFunctionObject::create(*vm.current_realm(), function_node.name(), function_node.source_text(), function_node.body(), function_node.parameters(), function_node.function_length(), function_node.local_variables_names(), vm.lexical_environment(), vm.running_execution_context().private_environment, function_node.kind(), function_node.is_strict_mode(), function_node.might_need_arguments_object(), function_node.contains_direct_call_to_eval(), function_node.is_arrow_function());
}
if (home_object.has_value()) {
auto home_object_value = vm.bytecode_interpreter().reg(home_object.value());
static_cast<ECMAScriptFunctionObject&>(value.as_function()).set_home_object(&home_object_value.as_object());
}
return value;
}
ThrowCompletionOr<void> put_by_value(VM& vm, Value base, Value property_key_value, Value value, Op::PropertyKind kind)
{
// OPTIMIZATION: Fast path for simple Int32 indexes in array-like objects.
if (base.is_object() && property_key_value.is_int32() && property_key_value.as_i32() >= 0) {
auto& object = base.as_object();
auto* storage = object.indexed_properties().storage();
auto index = static_cast<u32>(property_key_value.as_i32());
if (storage
&& storage->is_simple_storage()
&& !object.may_interfere_with_indexed_property_access()
&& storage->has_index(index)) {
auto existing_value = storage->get(index)->value;
if (!existing_value.is_accessor()) {
storage->put(index, value);
return {};
}
}
}
auto property_key = kind != Op::PropertyKind::Spread ? TRY(property_key_value.to_property_key(vm)) : PropertyKey {};
TRY(put_by_property_key(vm, base, base, value, property_key, kind));
return {};
}
ThrowCompletionOr<Value> get_variable(Bytecode::Interpreter& interpreter, DeprecatedFlyString const& name, u32 cache_index)
{
auto& vm = interpreter.vm();
auto& cached_environment_coordinate = interpreter.current_executable().environment_variable_caches[cache_index];
if (cached_environment_coordinate.has_value()) {
auto environment = vm.running_execution_context().lexical_environment;
for (size_t i = 0; i < cached_environment_coordinate->hops; ++i)
environment = environment->outer_environment();
VERIFY(environment);
VERIFY(environment->is_declarative_environment());
if (!environment->is_permanently_screwed_by_eval()) {
return TRY(verify_cast<DeclarativeEnvironment>(*environment).get_binding_value_direct(vm, cached_environment_coordinate.value().index, vm.in_strict_mode()));
}
cached_environment_coordinate = {};
}
auto reference = TRY(vm.resolve_binding(name));
if (reference.environment_coordinate().has_value())
cached_environment_coordinate = reference.environment_coordinate();
return TRY(reference.get_value(vm));
}
ThrowCompletionOr<CalleeAndThis> get_callee_and_this_from_environment(Bytecode::Interpreter& interpreter, DeprecatedFlyString const& name, u32 cache_index)
{
auto& vm = interpreter.vm();
Value callee = js_undefined();
Value this_value = js_undefined();
auto& cached_environment_coordinate = interpreter.current_executable().environment_variable_caches[cache_index];
if (cached_environment_coordinate.has_value()) {
auto environment = vm.running_execution_context().lexical_environment;
for (size_t i = 0; i < cached_environment_coordinate->hops; ++i)
environment = environment->outer_environment();
VERIFY(environment);
VERIFY(environment->is_declarative_environment());
if (!environment->is_permanently_screwed_by_eval()) {
callee = TRY(verify_cast<DeclarativeEnvironment>(*environment).get_binding_value_direct(vm, cached_environment_coordinate.value().index, vm.in_strict_mode()));
this_value = js_undefined();
if (auto base_object = environment->with_base_object())
this_value = base_object;
return CalleeAndThis {
.callee = callee,
.this_value = this_value,
};
}
cached_environment_coordinate = {};
}
auto reference = TRY(vm.resolve_binding(name));
if (reference.environment_coordinate().has_value())
cached_environment_coordinate = reference.environment_coordinate();
callee = TRY(reference.get_value(vm));
if (reference.is_property_reference()) {
this_value = reference.get_this_value();
} else {
if (reference.is_environment_reference()) {
if (auto base_object = reference.base_environment().with_base_object(); base_object != nullptr)
this_value = base_object;
}
}
return CalleeAndThis {
.callee = callee,
.this_value = this_value,
};
}
// 13.2.7.3 Runtime Semantics: Evaluation, https://tc39.es/ecma262/#sec-regular-expression-literals-runtime-semantics-evaluation
Value new_regexp(VM& vm, ParsedRegex const& parsed_regex, DeprecatedString const& pattern, DeprecatedString const& flags)
{
// 1. Let pattern be CodePointsToString(BodyText of RegularExpressionLiteral).
// 2. Let flags be CodePointsToString(FlagText of RegularExpressionLiteral).
// 3. Return ! RegExpCreate(pattern, flags).
auto& realm = *vm.current_realm();
Regex<ECMA262> regex(parsed_regex.regex, parsed_regex.pattern, parsed_regex.flags);
// NOTE: We bypass RegExpCreate and subsequently RegExpAlloc as an optimization to use the already parsed values.
auto regexp_object = RegExpObject::create(realm, move(regex), pattern, flags);
// RegExpAlloc has these two steps from the 'Legacy RegExp features' proposal.
regexp_object->set_realm(realm);
// We don't need to check 'If SameValue(newTarget, thisRealm.[[Intrinsics]].[[%RegExp%]]) is true'
// here as we know RegExpCreate calls RegExpAlloc with %RegExp% for newTarget.
regexp_object->set_legacy_features_enabled(true);
return regexp_object;
}
// 13.3.8.1 https://tc39.es/ecma262/#sec-runtime-semantics-argumentlistevaluation
MarkedVector<Value> argument_list_evaluation(Bytecode::Interpreter& interpreter)
{
// Note: Any spreading and actual evaluation is handled in preceding opcodes
// Note: The spec uses the concept of a list, while we create a temporary array
// in the preceding opcodes, so we have to convert in a manner that is not
// visible to the user
auto& vm = interpreter.vm();
MarkedVector<Value> argument_values { vm.heap() };
auto arguments = interpreter.accumulator();
auto& argument_array = arguments.as_array();
auto array_length = argument_array.indexed_properties().array_like_size();
argument_values.ensure_capacity(array_length);
for (size_t i = 0; i < array_length; ++i) {
if (auto maybe_value = argument_array.indexed_properties().get(i); maybe_value.has_value())
argument_values.append(maybe_value.release_value().value);
else
argument_values.append(js_undefined());
}
return argument_values;
}
ThrowCompletionOr<void> create_variable(VM& vm, DeprecatedFlyString const& name, Op::EnvironmentMode mode, bool is_global, bool is_immutable, bool is_strict)
{
if (mode == Op::EnvironmentMode::Lexical) {
VERIFY(!is_global);
// Note: This is papering over an issue where "FunctionDeclarationInstantiation" creates these bindings for us.
// Instead of crashing in there, we'll just raise an exception here.
if (TRY(vm.lexical_environment()->has_binding(name)))
return vm.throw_completion<InternalError>(TRY_OR_THROW_OOM(vm, String::formatted("Lexical environment already has binding '{}'", name)));
if (is_immutable)
return vm.lexical_environment()->create_immutable_binding(vm, name, is_strict);
return vm.lexical_environment()->create_mutable_binding(vm, name, is_strict);
}
if (!is_global) {
if (is_immutable)
return vm.variable_environment()->create_immutable_binding(vm, name, is_strict);
return vm.variable_environment()->create_mutable_binding(vm, name, is_strict);
}
// NOTE: CreateVariable with m_is_global set to true is expected to only be used in GlobalDeclarationInstantiation currently, which only uses "false" for "can_be_deleted".
// The only area that sets "can_be_deleted" to true is EvalDeclarationInstantiation, which is currently fully implemented in C++ and not in Bytecode.
return verify_cast<GlobalEnvironment>(vm.variable_environment())->create_global_var_binding(name, false);
}
ThrowCompletionOr<ECMAScriptFunctionObject*> new_class(VM& vm, ClassExpression const& class_expression, Optional<IdentifierTableIndex> const& lhs_name)
{
auto& interpreter = vm.bytecode_interpreter();
auto name = class_expression.name();
auto super_class = interpreter.accumulator();
// NOTE: NewClass expects classEnv to be active lexical environment
auto* class_environment = vm.lexical_environment();
vm.running_execution_context().lexical_environment = interpreter.saved_lexical_environment_stack().take_last();
DeprecatedFlyString binding_name;
DeprecatedFlyString class_name;
if (!class_expression.has_name() && lhs_name.has_value()) {
class_name = interpreter.current_executable().get_identifier(lhs_name.value());
} else {
binding_name = name;
class_name = name.is_null() ? ""sv : name;
}
return TRY(class_expression.create_class_constructor(vm, class_environment, vm.lexical_environment(), super_class, binding_name, class_name));
}
// 13.3.7.1 Runtime Semantics: Evaluation, https://tc39.es/ecma262/#sec-super-keyword-runtime-semantics-evaluation
ThrowCompletionOr<NonnullGCPtr<Object>> super_call_with_argument_array(VM& vm, Value argument_array, bool is_synthetic)
{
auto& interpreter = vm.bytecode_interpreter();
// 1. Let newTarget be GetNewTarget().
auto new_target = vm.get_new_target();
// 2. Assert: Type(newTarget) is Object.
VERIFY(new_target.is_object());
// 3. Let func be GetSuperConstructor().
auto* func = get_super_constructor(vm);
// 4. Let argList be ? ArgumentListEvaluation of Arguments.
MarkedVector<Value> arg_list { vm.heap() };
if (is_synthetic) {
VERIFY(argument_array.is_object() && is<Array>(argument_array.as_object()));
auto const& array_value = static_cast<Array const&>(argument_array.as_object());
auto length = MUST(length_of_array_like(vm, array_value));
for (size_t i = 0; i < length; ++i)
arg_list.append(array_value.get_without_side_effects(PropertyKey { i }));
} else {
arg_list = argument_list_evaluation(interpreter);
}
// 5. If IsConstructor(func) is false, throw a TypeError exception.
if (!Value(func).is_constructor())
return vm.throw_completion<TypeError>(ErrorType::NotAConstructor, "Super constructor");
// 6. Let result be ? Construct(func, argList, newTarget).
auto result = TRY(construct(vm, static_cast<FunctionObject&>(*func), move(arg_list), &new_target.as_function()));
// 7. Let thisER be GetThisEnvironment().
auto& this_environment = verify_cast<FunctionEnvironment>(*get_this_environment(vm));
// 8. Perform ? thisER.BindThisValue(result).
TRY(this_environment.bind_this_value(vm, result));
// 9. Let F be thisER.[[FunctionObject]].
auto& f = this_environment.function_object();
// 10. Assert: F is an ECMAScript function object.
// NOTE: This is implied by the strong C++ type.
// 11. Perform ? InitializeInstanceElements(result, F).
TRY(result->initialize_instance_elements(f));
// 12. Return result.
return result;
}
// FIXME: Since the accumulator is a Value, we store an object there and have to convert back and forth between that an Iterator records. Not great.
// Make sure to put this into the accumulator before the iterator object disappears from the stack to prevent the members from being GC'd.
Object* iterator_to_object(VM& vm, IteratorRecord iterator)
{
auto& realm = *vm.current_realm();
auto object = Object::create(realm, nullptr);
object->define_direct_property(vm.names.iterator, iterator.iterator, 0);
object->define_direct_property(vm.names.next, iterator.next_method, 0);
object->define_direct_property(vm.names.done, Value(iterator.done), 0);
return object;
}
IteratorRecord object_to_iterator(VM& vm, Object& object)
{
return IteratorRecord {
.iterator = &MUST(object.get(vm.names.iterator)).as_object(),
.next_method = MUST(object.get(vm.names.next)),
.done = MUST(object.get(vm.names.done)).as_bool()
};
}
ThrowCompletionOr<NonnullGCPtr<Array>> iterator_to_array(VM& vm, Value iterator)
{
auto iterator_object = TRY(iterator.to_object(vm));
auto iterator_record = object_to_iterator(vm, iterator_object);
auto array = MUST(Array::create(*vm.current_realm(), 0));
size_t index = 0;
while (true) {
auto iterator_result = TRY(iterator_next(vm, iterator_record));
auto complete = TRY(iterator_complete(vm, iterator_result));
if (complete)
return array;
auto value = TRY(iterator_value(vm, iterator_result));
MUST(array->create_data_property_or_throw(index, value));
index++;
}
}
ThrowCompletionOr<void> append(VM& vm, Value lhs, Value rhs, bool is_spread)
{
// Note: This OpCode is used to construct array literals and argument arrays for calls,
// containing at least one spread element,
// Iterating over such a spread element to unpack it has to be visible by
// the user courtesy of
// (1) https://tc39.es/ecma262/#sec-runtime-semantics-arrayaccumulation
// SpreadElement : ... AssignmentExpression
// 1. Let spreadRef be ? Evaluation of AssignmentExpression.
// 2. Let spreadObj be ? GetValue(spreadRef).
// 3. Let iteratorRecord be ? GetIterator(spreadObj).
// 4. Repeat,
// a. Let next be ? IteratorStep(iteratorRecord).
// b. If next is false, return nextIndex.
// c. Let nextValue be ? IteratorValue(next).
// d. Perform ! CreateDataPropertyOrThrow(array, ! ToString(𝔽(nextIndex)), nextValue).
// e. Set nextIndex to nextIndex + 1.
// (2) https://tc39.es/ecma262/#sec-runtime-semantics-argumentlistevaluation
// ArgumentList : ... AssignmentExpression
// 1. Let list be a new empty List.
// 2. Let spreadRef be ? Evaluation of AssignmentExpression.
// 3. Let spreadObj be ? GetValue(spreadRef).
// 4. Let iteratorRecord be ? GetIterator(spreadObj).
// 5. Repeat,
// a. Let next be ? IteratorStep(iteratorRecord).
// b. If next is false, return list.
// c. Let nextArg be ? IteratorValue(next).
// d. Append nextArg to list.
// ArgumentList : ArgumentList , ... AssignmentExpression
// 1. Let precedingArgs be ? ArgumentListEvaluation of ArgumentList.
// 2. Let spreadRef be ? Evaluation of AssignmentExpression.
// 3. Let iteratorRecord be ? GetIterator(? GetValue(spreadRef)).
// 4. Repeat,
// a. Let next be ? IteratorStep(iteratorRecord).
// b. If next is false, return precedingArgs.
// c. Let nextArg be ? IteratorValue(next).
// d. Append nextArg to precedingArgs.
// Note: We know from codegen, that lhs is a plain array with only indexed properties
auto& lhs_array = lhs.as_array();
auto lhs_size = lhs_array.indexed_properties().array_like_size();
if (is_spread) {
// ...rhs
size_t i = lhs_size;
TRY(get_iterator_values(vm, rhs, [&i, &lhs_array](Value iterator_value) -> Optional<Completion> {
lhs_array.indexed_properties().put(i, iterator_value, default_attributes);
++i;
return {};
}));
} else {
lhs_array.indexed_properties().put(lhs_size, rhs, default_attributes);
}
return {};
}
ThrowCompletionOr<Value> delete_by_id(Bytecode::Interpreter& interpreter, Value base, IdentifierTableIndex property)
{
auto& vm = interpreter.vm();
auto const& identifier = interpreter.current_executable().get_identifier(property);
bool strict = vm.in_strict_mode();
auto reference = Reference { base, identifier, {}, strict };
return TRY(reference.delete_(vm));
}
ThrowCompletionOr<Value> delete_by_value(Bytecode::Interpreter& interpreter, Value base, Value property_key_value)
{
auto& vm = interpreter.vm();
auto property_key = TRY(property_key_value.to_property_key(vm));
bool strict = vm.in_strict_mode();
auto reference = Reference { base, property_key, {}, strict };
return Value(TRY(reference.delete_(vm)));
}
ThrowCompletionOr<Value> delete_by_value_with_this(Bytecode::Interpreter& interpreter, Value base, Value property_key_value, Value this_value)
{
auto& vm = interpreter.vm();
auto property_key = TRY(property_key_value.to_property_key(vm));
bool strict = vm.in_strict_mode();
auto reference = Reference { base, property_key, this_value, strict };
return Value(TRY(reference.delete_(vm)));
}
// 14.7.5.9 EnumerateObjectProperties ( O ), https://tc39.es/ecma262/#sec-enumerate-object-properties
ThrowCompletionOr<Object*> get_object_property_iterator(VM& vm, Value value)
{
// While the spec does provide an algorithm, it allows us to implement it ourselves so long as we meet the following invariants:
// 1- Returned property keys do not include keys that are Symbols
// 2- Properties of the target object may be deleted during enumeration. A property that is deleted before it is processed by the iterator's next method is ignored
// 3- If new properties are added to the target object during enumeration, the newly added properties are not guaranteed to be processed in the active enumeration
// 4- A property name will be returned by the iterator's next method at most once in any enumeration.
// 5- Enumerating the properties of the target object includes enumerating properties of its prototype, and the prototype of the prototype, and so on, recursively;
// but a property of a prototype is not processed if it has the same name as a property that has already been processed by the iterator's next method.
// 6- The values of [[Enumerable]] attributes are not considered when determining if a property of a prototype object has already been processed.
// 7- The enumerable property names of prototype objects must be obtained by invoking EnumerateObjectProperties passing the prototype object as the argument.
// 8- EnumerateObjectProperties must obtain the own property keys of the target object by calling its [[OwnPropertyKeys]] internal method.
// 9- Property attributes of the target object must be obtained by calling its [[GetOwnProperty]] internal method
// Invariant 3 effectively allows the implementation to ignore newly added keys, and we do so (similar to other implementations).
auto object = TRY(value.to_object(vm));
// Note: While the spec doesn't explicitly require these to be ordered, it says that the values should be retrieved via OwnPropertyKeys,
// so we just keep the order consistent anyway.
OrderedHashTable<PropertyKey> properties;
OrderedHashTable<PropertyKey> non_enumerable_properties;
HashTable<NonnullGCPtr<Object>> seen_objects;
// Collect all keys immediately (invariant no. 5)
for (auto object_to_check = GCPtr { object.ptr() }; object_to_check && !seen_objects.contains(*object_to_check); object_to_check = TRY(object_to_check->internal_get_prototype_of())) {
seen_objects.set(*object_to_check);
for (auto& key : TRY(object_to_check->internal_own_property_keys())) {
if (key.is_symbol())
continue;
auto property_key = TRY(PropertyKey::from_value(vm, key));
// If there is a non-enumerable property higher up the prototype chain with the same key,
// we mustn't include this property even if it's enumerable (invariant no. 5 and 6)
if (non_enumerable_properties.contains(property_key))
continue;
if (properties.contains(property_key))
continue;
auto descriptor = TRY(object_to_check->internal_get_own_property(property_key));
if (!*descriptor->enumerable)
non_enumerable_properties.set(move(property_key));
else
properties.set(move(property_key));
}
}
IteratorRecord iterator {
.iterator = object,
.next_method = NativeFunction::create(
*vm.current_realm(),
[items = move(properties)](VM& vm) mutable -> ThrowCompletionOr<Value> {
auto& realm = *vm.current_realm();
auto iterated_object_value = vm.this_value();
if (!iterated_object_value.is_object())
return vm.throw_completion<InternalError>("Invalid state for GetObjectPropertyIterator.next"sv);
auto& iterated_object = iterated_object_value.as_object();
auto result_object = Object::create(realm, nullptr);
while (true) {
if (items.is_empty()) {
result_object->define_direct_property(vm.names.done, JS::Value(true), default_attributes);
return result_object;
}
auto key = items.take_first();
// If the property is deleted, don't include it (invariant no. 2)
if (!TRY(iterated_object.has_property(key)))
continue;
result_object->define_direct_property(vm.names.done, JS::Value(false), default_attributes);
if (key.is_number())
result_object->define_direct_property(vm.names.value, PrimitiveString::create(vm, TRY_OR_THROW_OOM(vm, String::number(key.as_number()))), default_attributes);
else if (key.is_string())
result_object->define_direct_property(vm.names.value, PrimitiveString::create(vm, key.as_string()), default_attributes);
else
VERIFY_NOT_REACHED(); // We should not have non-string/number keys.
return result_object;
}
},
1,
vm.names.next),
.done = false,
};
return iterator_to_object(vm, move(iterator));
}
}