VM.cpp 51 KB

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  1. /*
  2. * Copyright (c) 2020-2023, Andreas Kling <kling@serenityos.org>
  3. * Copyright (c) 2020-2023, Linus Groh <linusg@serenityos.org>
  4. * Copyright (c) 2021-2022, David Tuin <davidot@serenityos.org>
  5. *
  6. * SPDX-License-Identifier: BSD-2-Clause
  7. */
  8. #include <AK/Array.h>
  9. #include <AK/Debug.h>
  10. #include <AK/LexicalPath.h>
  11. #include <AK/ScopeGuard.h>
  12. #include <AK/String.h>
  13. #include <AK/StringBuilder.h>
  14. #include <LibCore/DeprecatedFile.h>
  15. #include <LibFileSystem/FileSystem.h>
  16. #include <LibJS/AST.h>
  17. #include <LibJS/Interpreter.h>
  18. #include <LibJS/Runtime/AbstractOperations.h>
  19. #include <LibJS/Runtime/Array.h>
  20. #include <LibJS/Runtime/BoundFunction.h>
  21. #include <LibJS/Runtime/Completion.h>
  22. #include <LibJS/Runtime/ECMAScriptFunctionObject.h>
  23. #include <LibJS/Runtime/Error.h>
  24. #include <LibJS/Runtime/FinalizationRegistry.h>
  25. #include <LibJS/Runtime/FunctionEnvironment.h>
  26. #include <LibJS/Runtime/IteratorOperations.h>
  27. #include <LibJS/Runtime/NativeFunction.h>
  28. #include <LibJS/Runtime/PromiseCapability.h>
  29. #include <LibJS/Runtime/Reference.h>
  30. #include <LibJS/Runtime/Symbol.h>
  31. #include <LibJS/Runtime/VM.h>
  32. #include <LibJS/SourceTextModule.h>
  33. #include <LibJS/SyntheticModule.h>
  34. namespace JS {
  35. ErrorOr<NonnullRefPtr<VM>> VM::create(OwnPtr<CustomData> custom_data)
  36. {
  37. ErrorMessages error_messages {};
  38. error_messages[to_underlying(ErrorMessage::OutOfMemory)] = TRY(String::from_utf8(ErrorType::OutOfMemory.message()));
  39. auto vm = adopt_ref(*new VM(move(custom_data), move(error_messages)));
  40. WellKnownSymbols well_known_symbols {
  41. #define __JS_ENUMERATE(SymbolName, snake_name) \
  42. Symbol::create(*vm, TRY("Symbol." #SymbolName##_string), false),
  43. JS_ENUMERATE_WELL_KNOWN_SYMBOLS
  44. #undef __JS_ENUMERATE
  45. };
  46. vm->set_well_known_symbols(move(well_known_symbols));
  47. return vm;
  48. }
  49. template<u32... code_points>
  50. static constexpr auto make_single_ascii_character_strings(IndexSequence<code_points...>)
  51. {
  52. return AK::Array { (String::from_code_point(code_points))... };
  53. }
  54. static constexpr auto single_ascii_character_strings = make_single_ascii_character_strings(MakeIndexSequence<128>());
  55. VM::VM(OwnPtr<CustomData> custom_data, ErrorMessages error_messages)
  56. : m_heap(*this)
  57. , m_error_messages(move(error_messages))
  58. , m_custom_data(move(custom_data))
  59. {
  60. m_empty_string = m_heap.allocate_without_realm<PrimitiveString>(String {});
  61. for (size_t i = 0; i < single_ascii_character_strings.size(); ++i)
  62. m_single_ascii_character_strings[i] = m_heap.allocate_without_realm<PrimitiveString>(single_ascii_character_strings[i]);
  63. // Default hook implementations. These can be overridden by the host, for example, LibWeb overrides the default hooks to place promise jobs on the microtask queue.
  64. host_promise_rejection_tracker = [this](Promise& promise, Promise::RejectionOperation operation) {
  65. promise_rejection_tracker(promise, operation);
  66. };
  67. host_call_job_callback = [this](JobCallback& job_callback, Value this_value, MarkedVector<Value> arguments) {
  68. return call_job_callback(*this, job_callback, this_value, move(arguments));
  69. };
  70. host_enqueue_finalization_registry_cleanup_job = [this](FinalizationRegistry& finalization_registry) {
  71. enqueue_finalization_registry_cleanup_job(finalization_registry);
  72. };
  73. host_enqueue_promise_job = [this](Function<ThrowCompletionOr<Value>()> job, Realm* realm) {
  74. enqueue_promise_job(move(job), realm);
  75. };
  76. host_make_job_callback = [](FunctionObject& function_object) {
  77. return make_job_callback(function_object);
  78. };
  79. host_resolve_imported_module = [&](ScriptOrModule referencing_script_or_module, ModuleRequest const& specifier) {
  80. return resolve_imported_module(move(referencing_script_or_module), specifier);
  81. };
  82. host_import_module_dynamically = [&](ScriptOrModule, ModuleRequest const&, PromiseCapability const& promise_capability) -> ThrowCompletionOr<void> {
  83. // By default, we throw on dynamic imports this is to prevent arbitrary file access by scripts.
  84. VERIFY(current_realm());
  85. auto& realm = *current_realm();
  86. auto promise = Promise::create(realm);
  87. // If you are here because you want to enable dynamic module importing make sure it won't be a security problem
  88. // by checking the default implementation of HostImportModuleDynamically and creating your own hook or calling
  89. // vm.enable_default_host_import_module_dynamically_hook().
  90. promise->reject(MUST_OR_THROW_OOM(Error::create(realm, ErrorType::DynamicImportNotAllowed.message())));
  91. promise->perform_then(
  92. NativeFunction::create(realm, "", [](auto&) -> ThrowCompletionOr<Value> {
  93. VERIFY_NOT_REACHED();
  94. }),
  95. NativeFunction::create(realm, "", [&promise_capability](auto& vm) -> ThrowCompletionOr<Value> {
  96. auto error = vm.argument(0);
  97. // a. Perform ! Call(promiseCapability.[[Reject]], undefined, « error »).
  98. MUST(call(vm, *promise_capability.reject(), js_undefined(), error));
  99. // b. Return undefined.
  100. return js_undefined();
  101. }),
  102. {});
  103. return {};
  104. };
  105. host_finish_dynamic_import = [&](ScriptOrModule referencing_script_or_module, ModuleRequest const& specifier, PromiseCapability const& promise_capability, Promise* promise) {
  106. return finish_dynamic_import(move(referencing_script_or_module), specifier, promise_capability, promise);
  107. };
  108. host_get_import_meta_properties = [&](SourceTextModule const&) -> HashMap<PropertyKey, Value> {
  109. return {};
  110. };
  111. host_finalize_import_meta = [&](Object*, SourceTextModule const&) {
  112. };
  113. host_get_supported_import_assertions = [&] {
  114. return Vector<DeprecatedString> { "type" };
  115. };
  116. // 19.2.1.2 HostEnsureCanCompileStrings ( callerRealm, calleeRealm ), https://tc39.es/ecma262/#sec-hostensurecancompilestrings
  117. host_ensure_can_compile_strings = [](Realm&) -> ThrowCompletionOr<void> {
  118. // The host-defined abstract operation HostEnsureCanCompileStrings takes argument calleeRealm (a Realm Record)
  119. // and returns either a normal completion containing unused or a throw completion.
  120. // It allows host environments to block certain ECMAScript functions which allow developers to compile strings into ECMAScript code.
  121. // An implementation of HostEnsureCanCompileStrings must conform to the following requirements:
  122. // - If the returned Completion Record is a normal completion, it must be a normal completion containing unused.
  123. // The default implementation of HostEnsureCanCompileStrings is to return NormalCompletion(unused).
  124. return {};
  125. };
  126. host_ensure_can_add_private_element = [](Object&) -> ThrowCompletionOr<void> {
  127. // The host-defined abstract operation HostEnsureCanAddPrivateElement takes argument O (an Object)
  128. // and returns either a normal completion containing unused or a throw completion.
  129. // It allows host environments to prevent the addition of private elements to particular host-defined exotic objects.
  130. // An implementation of HostEnsureCanAddPrivateElement must conform to the following requirements:
  131. // - If O is not a host-defined exotic object, this abstract operation must return NormalCompletion(unused) and perform no other steps.
  132. // - Any two calls of this abstract operation with the same argument must return the same kind of Completion Record.
  133. // The default implementation of HostEnsureCanAddPrivateElement is to return NormalCompletion(unused).
  134. return {};
  135. // This abstract operation is only invoked by ECMAScript hosts that are web browsers.
  136. // NOTE: Since LibJS has no way of knowing whether the current environment is a browser we always
  137. // call HostEnsureCanAddPrivateElement when needed.
  138. };
  139. }
  140. String const& VM::error_message(ErrorMessage type) const
  141. {
  142. VERIFY(type < ErrorMessage::__Count);
  143. auto const& message = m_error_messages[to_underlying(type)];
  144. VERIFY(!message.is_empty());
  145. return message;
  146. }
  147. void VM::enable_default_host_import_module_dynamically_hook()
  148. {
  149. host_import_module_dynamically = [&](ScriptOrModule referencing_script_or_module, ModuleRequest const& specifier, PromiseCapability const& promise_capability) {
  150. return import_module_dynamically(move(referencing_script_or_module), specifier, promise_capability);
  151. };
  152. }
  153. Interpreter& VM::interpreter()
  154. {
  155. VERIFY(!m_interpreters.is_empty());
  156. return *m_interpreters.last();
  157. }
  158. Interpreter* VM::interpreter_if_exists()
  159. {
  160. if (m_interpreters.is_empty())
  161. return nullptr;
  162. return m_interpreters.last();
  163. }
  164. void VM::push_interpreter(Interpreter& interpreter)
  165. {
  166. m_interpreters.append(&interpreter);
  167. }
  168. void VM::pop_interpreter(Interpreter& interpreter)
  169. {
  170. VERIFY(!m_interpreters.is_empty());
  171. auto* popped_interpreter = m_interpreters.take_last();
  172. VERIFY(popped_interpreter == &interpreter);
  173. }
  174. VM::InterpreterExecutionScope::InterpreterExecutionScope(Interpreter& interpreter)
  175. : m_interpreter(interpreter)
  176. {
  177. m_interpreter.vm().push_interpreter(m_interpreter);
  178. }
  179. VM::InterpreterExecutionScope::~InterpreterExecutionScope()
  180. {
  181. m_interpreter.vm().pop_interpreter(m_interpreter);
  182. }
  183. void VM::gather_roots(HashTable<Cell*>& roots)
  184. {
  185. roots.set(m_empty_string);
  186. for (auto string : m_single_ascii_character_strings)
  187. roots.set(string);
  188. auto gather_roots_from_execution_context_stack = [&roots](Vector<ExecutionContext*> const& stack) {
  189. for (auto& execution_context : stack) {
  190. if (execution_context->this_value.is_cell())
  191. roots.set(&execution_context->this_value.as_cell());
  192. for (auto& argument : execution_context->arguments) {
  193. if (argument.is_cell())
  194. roots.set(&argument.as_cell());
  195. }
  196. roots.set(execution_context->lexical_environment);
  197. roots.set(execution_context->variable_environment);
  198. roots.set(execution_context->private_environment);
  199. if (auto context_owner = execution_context->context_owner)
  200. roots.set(context_owner);
  201. execution_context->script_or_module.visit(
  202. [](Empty) {},
  203. [&](auto& script_or_module) {
  204. roots.set(script_or_module.ptr());
  205. });
  206. }
  207. };
  208. gather_roots_from_execution_context_stack(m_execution_context_stack);
  209. for (auto& saved_stack : m_saved_execution_context_stacks)
  210. gather_roots_from_execution_context_stack(saved_stack);
  211. #define __JS_ENUMERATE(SymbolName, snake_name) \
  212. roots.set(well_known_symbol_##snake_name());
  213. JS_ENUMERATE_WELL_KNOWN_SYMBOLS
  214. #undef __JS_ENUMERATE
  215. for (auto& symbol : m_global_symbol_registry)
  216. roots.set(symbol.value);
  217. for (auto finalization_registry : m_finalization_registry_cleanup_jobs)
  218. roots.set(finalization_registry);
  219. }
  220. ThrowCompletionOr<Value> VM::named_evaluation_if_anonymous_function(ASTNode const& expression, DeprecatedFlyString const& name)
  221. {
  222. // 8.3.3 Static Semantics: IsAnonymousFunctionDefinition ( expr ), https://tc39.es/ecma262/#sec-isanonymousfunctiondefinition
  223. // And 8.3.5 Runtime Semantics: NamedEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-namedevaluation
  224. if (is<FunctionExpression>(expression)) {
  225. auto& function = static_cast<FunctionExpression const&>(expression);
  226. if (!function.has_name()) {
  227. return function.instantiate_ordinary_function_expression(interpreter(), name);
  228. }
  229. } else if (is<ClassExpression>(expression)) {
  230. auto& class_expression = static_cast<ClassExpression const&>(expression);
  231. if (!class_expression.has_name()) {
  232. return TRY(class_expression.class_definition_evaluation(interpreter(), {}, name));
  233. }
  234. }
  235. return TRY(expression.execute(interpreter())).release_value();
  236. }
  237. // 13.15.5.2 Runtime Semantics: DestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-destructuringassignmentevaluation
  238. ThrowCompletionOr<void> VM::destructuring_assignment_evaluation(NonnullRefPtr<BindingPattern const> const& target, Value value)
  239. {
  240. // Note: DestructuringAssignmentEvaluation is just like BindingInitialization without an environment
  241. // And it allows member expressions. We thus trust the parser to disallow member expressions
  242. // in any non assignment binding and just call BindingInitialization with a nullptr environment
  243. return binding_initialization(target, value, nullptr);
  244. }
  245. // 8.5.2 Runtime Semantics: BindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-bindinginitialization
  246. ThrowCompletionOr<void> VM::binding_initialization(DeprecatedFlyString const& target, Value value, Environment* environment)
  247. {
  248. // 1. Let name be StringValue of Identifier.
  249. // 2. Return ? InitializeBoundName(name, value, environment).
  250. return initialize_bound_name(*this, target, value, environment);
  251. }
  252. // 8.5.2 Runtime Semantics: BindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-bindinginitialization
  253. ThrowCompletionOr<void> VM::binding_initialization(NonnullRefPtr<BindingPattern const> const& target, Value value, Environment* environment)
  254. {
  255. auto& vm = *this;
  256. // BindingPattern : ObjectBindingPattern
  257. if (target->kind == BindingPattern::Kind::Object) {
  258. // 1. Perform ? RequireObjectCoercible(value).
  259. TRY(require_object_coercible(vm, value));
  260. // 2. Return ? BindingInitialization of ObjectBindingPattern with arguments value and environment.
  261. // BindingInitialization of ObjectBindingPattern
  262. // 1. Perform ? PropertyBindingInitialization of BindingPropertyList with arguments value and environment.
  263. TRY(property_binding_initialization(*target, value, environment));
  264. // 2. Return unused.
  265. return {};
  266. }
  267. // BindingPattern : ArrayBindingPattern
  268. else {
  269. // 1. Let iteratorRecord be ? GetIterator(value).
  270. auto iterator_record = TRY(get_iterator(vm, value));
  271. // 2. Let result be Completion(IteratorBindingInitialization of ArrayBindingPattern with arguments iteratorRecord and environment).
  272. auto result = iterator_binding_initialization(*target, iterator_record, environment);
  273. // 3. If iteratorRecord.[[Done]] is false, return ? IteratorClose(iteratorRecord, result).
  274. if (!iterator_record.done) {
  275. // iterator_close() always returns a Completion, which ThrowCompletionOr will interpret as a throw
  276. // completion. So only return the result of iterator_close() if it is indeed a throw completion.
  277. auto completion = result.is_throw_completion() ? result.release_error() : normal_completion({});
  278. if (completion = iterator_close(vm, iterator_record, move(completion)); completion.is_error())
  279. return completion.release_error();
  280. }
  281. // 4. Return ? result.
  282. return result;
  283. }
  284. }
  285. // 13.15.5.3 Runtime Semantics: PropertyDestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-propertydestructuringassignmentevaluation
  286. // 14.3.3.1 Runtime Semantics: PropertyBindingInitialization, https://tc39.es/ecma262/#sec-destructuring-binding-patterns-runtime-semantics-propertybindinginitialization
  287. ThrowCompletionOr<void> VM::property_binding_initialization(BindingPattern const& binding, Value value, Environment* environment)
  288. {
  289. auto& vm = *this;
  290. auto& realm = *vm.current_realm();
  291. auto object = TRY(value.to_object(vm));
  292. HashTable<PropertyKey> seen_names;
  293. for (auto& property : binding.entries) {
  294. VERIFY(!property.is_elision());
  295. if (property.is_rest) {
  296. Reference assignment_target;
  297. if (auto identifier_ptr = property.name.get_pointer<NonnullRefPtr<Identifier const>>()) {
  298. assignment_target = TRY(resolve_binding((*identifier_ptr)->string(), environment));
  299. } else if (auto member_ptr = property.alias.get_pointer<NonnullRefPtr<MemberExpression const>>()) {
  300. assignment_target = TRY((*member_ptr)->to_reference(interpreter()));
  301. } else {
  302. VERIFY_NOT_REACHED();
  303. }
  304. auto rest_object = Object::create(realm, realm.intrinsics().object_prototype());
  305. VERIFY(rest_object);
  306. TRY(rest_object->copy_data_properties(vm, object, seen_names));
  307. if (!environment)
  308. return assignment_target.put_value(vm, rest_object);
  309. else
  310. return assignment_target.initialize_referenced_binding(vm, rest_object);
  311. }
  312. auto name = TRY(property.name.visit(
  313. [&](Empty) -> ThrowCompletionOr<PropertyKey> { VERIFY_NOT_REACHED(); },
  314. [&](NonnullRefPtr<Identifier const> const& identifier) -> ThrowCompletionOr<PropertyKey> {
  315. return identifier->string();
  316. },
  317. [&](NonnullRefPtr<Expression const> const& expression) -> ThrowCompletionOr<PropertyKey> {
  318. auto result = TRY(expression->execute(interpreter())).release_value();
  319. return result.to_property_key(vm);
  320. }));
  321. seen_names.set(name);
  322. if (property.name.has<NonnullRefPtr<Identifier const>>() && property.alias.has<Empty>()) {
  323. // FIXME: this branch and not taking this have a lot in common we might want to unify it more (like it was before).
  324. auto& identifier = *property.name.get<NonnullRefPtr<Identifier const>>();
  325. auto reference = TRY(resolve_binding(identifier.string(), environment));
  326. auto value_to_assign = TRY(object->get(name));
  327. if (property.initializer && value_to_assign.is_undefined()) {
  328. value_to_assign = TRY(named_evaluation_if_anonymous_function(*property.initializer, identifier.string()));
  329. }
  330. if (!environment)
  331. TRY(reference.put_value(vm, value_to_assign));
  332. else
  333. TRY(reference.initialize_referenced_binding(vm, value_to_assign));
  334. continue;
  335. }
  336. auto reference_to_assign_to = TRY(property.alias.visit(
  337. [&](Empty) -> ThrowCompletionOr<Optional<Reference>> { return Optional<Reference> {}; },
  338. [&](NonnullRefPtr<Identifier const> const& identifier) -> ThrowCompletionOr<Optional<Reference>> {
  339. return TRY(resolve_binding(identifier->string(), environment));
  340. },
  341. [&](NonnullRefPtr<BindingPattern const> const&) -> ThrowCompletionOr<Optional<Reference>> { return Optional<Reference> {}; },
  342. [&](NonnullRefPtr<MemberExpression const> const& member_expression) -> ThrowCompletionOr<Optional<Reference>> {
  343. return TRY(member_expression->to_reference(interpreter()));
  344. }));
  345. auto value_to_assign = TRY(object->get(name));
  346. if (property.initializer && value_to_assign.is_undefined()) {
  347. if (auto* identifier_ptr = property.alias.get_pointer<NonnullRefPtr<Identifier const>>())
  348. value_to_assign = TRY(named_evaluation_if_anonymous_function(*property.initializer, (*identifier_ptr)->string()));
  349. else
  350. value_to_assign = TRY(property.initializer->execute(interpreter())).release_value();
  351. }
  352. if (auto* binding_ptr = property.alias.get_pointer<NonnullRefPtr<BindingPattern const>>()) {
  353. TRY(binding_initialization(*binding_ptr, value_to_assign, environment));
  354. } else {
  355. VERIFY(reference_to_assign_to.has_value());
  356. if (!environment)
  357. TRY(reference_to_assign_to->put_value(vm, value_to_assign));
  358. else
  359. TRY(reference_to_assign_to->initialize_referenced_binding(vm, value_to_assign));
  360. }
  361. }
  362. return {};
  363. }
  364. // 13.15.5.5 Runtime Semantics: IteratorDestructuringAssignmentEvaluation, https://tc39.es/ecma262/#sec-runtime-semantics-iteratordestructuringassignmentevaluation
  365. // 8.5.3 Runtime Semantics: IteratorBindingInitialization, https://tc39.es/ecma262/#sec-runtime-semantics-iteratorbindinginitialization
  366. ThrowCompletionOr<void> VM::iterator_binding_initialization(BindingPattern const& binding, Iterator& iterator_record, Environment* environment)
  367. {
  368. auto& vm = *this;
  369. auto& realm = *vm.current_realm();
  370. // FIXME: this method is nearly identical to destructuring assignment!
  371. for (size_t i = 0; i < binding.entries.size(); i++) {
  372. auto& entry = binding.entries[i];
  373. Value value;
  374. auto assignment_target = TRY(entry.alias.visit(
  375. [&](Empty) -> ThrowCompletionOr<Optional<Reference>> { return Optional<Reference> {}; },
  376. [&](NonnullRefPtr<Identifier const> const& identifier) -> ThrowCompletionOr<Optional<Reference>> {
  377. return TRY(resolve_binding(identifier->string(), environment));
  378. },
  379. [&](NonnullRefPtr<BindingPattern const> const&) -> ThrowCompletionOr<Optional<Reference>> { return Optional<Reference> {}; },
  380. [&](NonnullRefPtr<MemberExpression const> const& member_expression) -> ThrowCompletionOr<Optional<Reference>> {
  381. return TRY(member_expression->to_reference(interpreter()));
  382. }));
  383. // BindingRestElement : ... BindingIdentifier
  384. // BindingRestElement : ... BindingPattern
  385. if (entry.is_rest) {
  386. VERIFY(i == binding.entries.size() - 1);
  387. // 2. Let A be ! ArrayCreate(0).
  388. auto array = MUST(Array::create(realm, 0));
  389. // 3. Let n be 0.
  390. // 4. Repeat,
  391. while (true) {
  392. ThrowCompletionOr<GCPtr<Object>> next { nullptr };
  393. // a. If iteratorRecord.[[Done]] is false, then
  394. if (!iterator_record.done) {
  395. // i. Let next be Completion(IteratorStep(iteratorRecord)).
  396. next = iterator_step(vm, iterator_record);
  397. // ii. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
  398. // iii. ReturnIfAbrupt(next).
  399. if (next.is_error()) {
  400. iterator_record.done = true;
  401. return next.release_error();
  402. }
  403. // iv. If next is false, set iteratorRecord.[[Done]] to true.
  404. if (!next.value())
  405. iterator_record.done = true;
  406. }
  407. // b. If iteratorRecord.[[Done]] is true, then
  408. if (iterator_record.done) {
  409. // NOTE: Step i. and ii. are handled below.
  410. break;
  411. }
  412. // c. Let nextValue be Completion(IteratorValue(next)).
  413. auto next_value = iterator_value(vm, *next.value());
  414. // d. If nextValue is an abrupt completion, set iteratorRecord.[[Done]] to true.
  415. // e. ReturnIfAbrupt(nextValue).
  416. if (next_value.is_error()) {
  417. iterator_record.done = true;
  418. return next_value.release_error();
  419. }
  420. // f. Perform ! CreateDataPropertyOrThrow(A, ! ToString(𝔽(n)), nextValue).
  421. array->indexed_properties().append(next_value.value());
  422. // g. Set n to n + 1.
  423. }
  424. value = array;
  425. }
  426. // SingleNameBinding : BindingIdentifier Initializer[opt]
  427. // BindingElement : BindingPattern Initializer[opt]
  428. else {
  429. // 1. Let v be undefined.
  430. value = js_undefined();
  431. // 2. If iteratorRecord.[[Done]] is false, then
  432. if (!iterator_record.done) {
  433. // a. Let next be Completion(IteratorStep(iteratorRecord)).
  434. auto next = iterator_step(vm, iterator_record);
  435. // b. If next is an abrupt completion, set iteratorRecord.[[Done]] to true.
  436. // c. ReturnIfAbrupt(next).
  437. if (next.is_error()) {
  438. iterator_record.done = true;
  439. return next.release_error();
  440. }
  441. // d. If next is false, set iteratorRecord.[[Done]] to true.
  442. if (!next.value()) {
  443. iterator_record.done = true;
  444. }
  445. // e. Else,
  446. else {
  447. // i. Set v to Completion(IteratorValue(next)).
  448. auto value_or_error = iterator_value(vm, *next.value());
  449. // ii. If v is an abrupt completion, set iteratorRecord.[[Done]] to true.
  450. // iii. ReturnIfAbrupt(v).
  451. if (value_or_error.is_throw_completion()) {
  452. iterator_record.done = true;
  453. return value_or_error.release_error();
  454. }
  455. value = value_or_error.release_value();
  456. }
  457. }
  458. // NOTE: Step 3. and 4. are handled below.
  459. }
  460. if (value.is_undefined() && entry.initializer) {
  461. VERIFY(!entry.is_rest);
  462. if (auto* identifier_ptr = entry.alias.get_pointer<NonnullRefPtr<Identifier const>>())
  463. value = TRY(named_evaluation_if_anonymous_function(*entry.initializer, (*identifier_ptr)->string()));
  464. else
  465. value = TRY(entry.initializer->execute(interpreter())).release_value();
  466. }
  467. if (auto* binding_ptr = entry.alias.get_pointer<NonnullRefPtr<BindingPattern const>>()) {
  468. TRY(binding_initialization(*binding_ptr, value, environment));
  469. } else if (!entry.alias.has<Empty>()) {
  470. VERIFY(assignment_target.has_value());
  471. if (!environment)
  472. TRY(assignment_target->put_value(vm, value));
  473. else
  474. TRY(assignment_target->initialize_referenced_binding(vm, value));
  475. }
  476. }
  477. return {};
  478. }
  479. // 9.1.2.1 GetIdentifierReference ( env, name, strict ), https://tc39.es/ecma262/#sec-getidentifierreference
  480. ThrowCompletionOr<Reference> VM::get_identifier_reference(Environment* environment, DeprecatedFlyString name, bool strict, size_t hops)
  481. {
  482. // 1. If env is the value null, then
  483. if (!environment) {
  484. // a. Return the Reference Record { [[Base]]: unresolvable, [[ReferencedName]]: name, [[Strict]]: strict, [[ThisValue]]: empty }.
  485. return Reference { Reference::BaseType::Unresolvable, move(name), strict };
  486. }
  487. // 2. Let exists be ? env.HasBinding(name).
  488. Optional<size_t> index;
  489. auto exists = TRY(environment->has_binding(name, &index));
  490. // Note: This is an optimization for looking up the same reference.
  491. Optional<EnvironmentCoordinate> environment_coordinate;
  492. if (index.has_value()) {
  493. VERIFY(hops <= NumericLimits<u32>::max());
  494. VERIFY(index.value() <= NumericLimits<u32>::max());
  495. environment_coordinate = EnvironmentCoordinate { .hops = static_cast<u32>(hops), .index = static_cast<u32>(index.value()) };
  496. }
  497. // 3. If exists is true, then
  498. if (exists) {
  499. // a. Return the Reference Record { [[Base]]: env, [[ReferencedName]]: name, [[Strict]]: strict, [[ThisValue]]: empty }.
  500. return Reference { *environment, move(name), strict, environment_coordinate };
  501. }
  502. // 4. Else,
  503. else {
  504. // a. Let outer be env.[[OuterEnv]].
  505. // b. Return ? GetIdentifierReference(outer, name, strict).
  506. return get_identifier_reference(environment->outer_environment(), move(name), strict, hops + 1);
  507. }
  508. }
  509. // 9.4.2 ResolveBinding ( name [ , env ] ), https://tc39.es/ecma262/#sec-resolvebinding
  510. ThrowCompletionOr<Reference> VM::resolve_binding(DeprecatedFlyString const& name, Environment* environment)
  511. {
  512. // 1. If env is not present or if env is undefined, then
  513. if (!environment) {
  514. // a. Set env to the running execution context's LexicalEnvironment.
  515. environment = running_execution_context().lexical_environment;
  516. }
  517. // 2. Assert: env is an Environment Record.
  518. VERIFY(environment);
  519. // 3. If the source text matched by the syntactic production that is being evaluated is contained in strict mode code, let strict be true; else let strict be false.
  520. bool strict = in_strict_mode();
  521. // 4. Return ? GetIdentifierReference(env, name, strict).
  522. return get_identifier_reference(environment, name, strict);
  523. // NOTE: The spec says:
  524. // Note: The result of ResolveBinding is always a Reference Record whose [[ReferencedName]] field is name.
  525. // But this is not actually correct as GetIdentifierReference (or really the methods it calls) can throw.
  526. }
  527. // 9.4.4 ResolveThisBinding ( ), https://tc39.es/ecma262/#sec-resolvethisbinding
  528. ThrowCompletionOr<Value> VM::resolve_this_binding()
  529. {
  530. auto& vm = *this;
  531. // 1. Let envRec be GetThisEnvironment().
  532. auto environment = get_this_environment(vm);
  533. // 2. Return ? envRec.GetThisBinding().
  534. return TRY(environment->get_this_binding(vm));
  535. }
  536. // 9.4.5 GetNewTarget ( ), https://tc39.es/ecma262/#sec-getnewtarget
  537. Value VM::get_new_target()
  538. {
  539. // 1. Let envRec be GetThisEnvironment().
  540. auto env = get_this_environment(*this);
  541. // 2. Assert: envRec has a [[NewTarget]] field.
  542. // 3. Return envRec.[[NewTarget]].
  543. return verify_cast<FunctionEnvironment>(*env).new_target();
  544. }
  545. // 9.4.5 GetGlobalObject ( ), https://tc39.es/ecma262/#sec-getglobalobject
  546. Object& VM::get_global_object()
  547. {
  548. // 1. Let currentRealm be the current Realm Record.
  549. auto& current_realm = *this->current_realm();
  550. // 2. Return currentRealm.[[GlobalObject]].
  551. return current_realm.global_object();
  552. }
  553. bool VM::in_strict_mode() const
  554. {
  555. if (execution_context_stack().is_empty())
  556. return false;
  557. return running_execution_context().is_strict_mode;
  558. }
  559. void VM::run_queued_promise_jobs()
  560. {
  561. dbgln_if(PROMISE_DEBUG, "Running queued promise jobs");
  562. while (!m_promise_jobs.is_empty()) {
  563. auto job = m_promise_jobs.take_first();
  564. dbgln_if(PROMISE_DEBUG, "Calling promise job function");
  565. [[maybe_unused]] auto result = job();
  566. }
  567. }
  568. // 9.5.4 HostEnqueuePromiseJob ( job, realm ), https://tc39.es/ecma262/#sec-hostenqueuepromisejob
  569. void VM::enqueue_promise_job(Function<ThrowCompletionOr<Value>()> job, Realm*)
  570. {
  571. // An implementation of HostEnqueuePromiseJob must conform to the requirements in 9.5 as well as the following:
  572. // - FIXME: If realm is not null, each time job is invoked the implementation must perform implementation-defined steps such that execution is prepared to evaluate ECMAScript code at the time of job's invocation.
  573. // - FIXME: Let scriptOrModule be GetActiveScriptOrModule() at the time HostEnqueuePromiseJob is invoked. If realm is not null, each time job is invoked the implementation must perform implementation-defined steps
  574. // such that scriptOrModule is the active script or module at the time of job's invocation.
  575. // - Jobs must run in the same order as the HostEnqueuePromiseJob invocations that scheduled them.
  576. m_promise_jobs.append(move(job));
  577. }
  578. void VM::run_queued_finalization_registry_cleanup_jobs()
  579. {
  580. while (!m_finalization_registry_cleanup_jobs.is_empty()) {
  581. auto registry = m_finalization_registry_cleanup_jobs.take_first();
  582. // FIXME: Handle any uncatched exceptions here.
  583. (void)registry->cleanup();
  584. }
  585. }
  586. // 9.10.4.1 HostEnqueueFinalizationRegistryCleanupJob ( finalizationRegistry ), https://tc39.es/ecma262/#sec-host-cleanup-finalization-registry
  587. void VM::enqueue_finalization_registry_cleanup_job(FinalizationRegistry& registry)
  588. {
  589. m_finalization_registry_cleanup_jobs.append(&registry);
  590. }
  591. // 27.2.1.9 HostPromiseRejectionTracker ( promise, operation ), https://tc39.es/ecma262/#sec-host-promise-rejection-tracker
  592. void VM::promise_rejection_tracker(Promise& promise, Promise::RejectionOperation operation) const
  593. {
  594. switch (operation) {
  595. case Promise::RejectionOperation::Reject:
  596. // A promise was rejected without any handlers
  597. if (on_promise_unhandled_rejection)
  598. on_promise_unhandled_rejection(promise);
  599. break;
  600. case Promise::RejectionOperation::Handle:
  601. // A handler was added to an already rejected promise
  602. if (on_promise_rejection_handled)
  603. on_promise_rejection_handled(promise);
  604. break;
  605. default:
  606. VERIFY_NOT_REACHED();
  607. }
  608. }
  609. void VM::dump_backtrace() const
  610. {
  611. for (ssize_t i = m_execution_context_stack.size() - 1; i >= 0; --i) {
  612. auto& frame = m_execution_context_stack[i];
  613. if (frame->current_node) {
  614. auto source_range = frame->current_node->source_range();
  615. dbgln("-> {} @ {}:{},{}", frame->function_name, source_range.filename(), source_range.start.line, source_range.start.column);
  616. } else {
  617. dbgln("-> {}", frame->function_name);
  618. }
  619. }
  620. }
  621. void VM::save_execution_context_stack()
  622. {
  623. m_saved_execution_context_stacks.append(move(m_execution_context_stack));
  624. }
  625. void VM::restore_execution_context_stack()
  626. {
  627. m_execution_context_stack = m_saved_execution_context_stacks.take_last();
  628. }
  629. // 9.4.1 GetActiveScriptOrModule ( ), https://tc39.es/ecma262/#sec-getactivescriptormodule
  630. ScriptOrModule VM::get_active_script_or_module() const
  631. {
  632. // 1. If the execution context stack is empty, return null.
  633. if (m_execution_context_stack.is_empty())
  634. return Empty {};
  635. // 2. Let ec be the topmost execution context on the execution context stack whose ScriptOrModule component is not null.
  636. for (auto i = m_execution_context_stack.size() - 1; i > 0; i--) {
  637. if (!m_execution_context_stack[i]->script_or_module.has<Empty>())
  638. return m_execution_context_stack[i]->script_or_module;
  639. }
  640. // 3. If no such execution context exists, return null. Otherwise, return ec's ScriptOrModule.
  641. // Note: Since it is not empty we have 0 and since we got here all the
  642. // above contexts don't have a non-null ScriptOrModule
  643. return m_execution_context_stack[0]->script_or_module;
  644. }
  645. VM::StoredModule* VM::get_stored_module(ScriptOrModule const&, DeprecatedString const& filename, DeprecatedString const&)
  646. {
  647. // Note the spec says:
  648. // Each time this operation is called with a specific referencingScriptOrModule, specifier pair as arguments
  649. // it must return the same Module Record instance if it completes normally.
  650. // Currently, we ignore the referencing script or module but this might not be correct in all cases.
  651. // Editor's Note from https://tc39.es/proposal-json-modules/#sec-hostresolveimportedmodule
  652. // The above text implies that is recommended but not required that hosts do not use moduleRequest.[[Assertions]]
  653. // as part of the module cache key. In either case, an exception thrown from an import with a given assertion list
  654. // does not rule out success of another import with the same specifier but a different assertion list.
  655. auto end_or_module = m_loaded_modules.find_if([&](StoredModule const& stored_module) {
  656. return stored_module.filename == filename;
  657. });
  658. if (end_or_module.is_end())
  659. return nullptr;
  660. return &(*end_or_module);
  661. }
  662. ThrowCompletionOr<void> VM::link_and_eval_module(Badge<Interpreter>, SourceTextModule& module)
  663. {
  664. return link_and_eval_module(module);
  665. }
  666. ThrowCompletionOr<void> VM::link_and_eval_module(Module& module)
  667. {
  668. auto filename = module.filename();
  669. auto module_or_end = m_loaded_modules.find_if([&](StoredModule const& stored_module) {
  670. return stored_module.module.ptr() == &module;
  671. });
  672. StoredModule* stored_module;
  673. if (module_or_end.is_end()) {
  674. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] Warning introducing module via link_and_eval_module {}", module.filename());
  675. if (m_loaded_modules.size() > 0)
  676. dbgln("Warning: Using multiple modules as entry point can lead to unexpected results");
  677. m_loaded_modules.empend(
  678. NonnullGCPtr(module),
  679. module.filename(),
  680. DeprecatedString {}, // Null type
  681. module,
  682. true);
  683. stored_module = &m_loaded_modules.last();
  684. } else {
  685. stored_module = module_or_end.operator->();
  686. if (stored_module->has_once_started_linking) {
  687. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] Module already has started linking once {}", module.filename());
  688. return {};
  689. }
  690. stored_module->has_once_started_linking = true;
  691. }
  692. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] Linking module {}", filename);
  693. auto linked_or_error = module.link(*this);
  694. if (linked_or_error.is_error())
  695. return linked_or_error.throw_completion();
  696. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] Linking passed, now evaluating module {}", filename);
  697. auto evaluated_or_error = module.evaluate(*this);
  698. if (evaluated_or_error.is_error())
  699. return evaluated_or_error.throw_completion();
  700. auto* evaluated_value = evaluated_or_error.value();
  701. run_queued_promise_jobs();
  702. VERIFY(m_promise_jobs.is_empty());
  703. // FIXME: This will break if we start doing promises actually asynchronously.
  704. VERIFY(evaluated_value->state() != Promise::State::Pending);
  705. if (evaluated_value->state() == Promise::State::Rejected)
  706. return JS::throw_completion(evaluated_value->result());
  707. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] Evaluating passed for module {}", module.filename());
  708. return {};
  709. }
  710. static DeprecatedString resolve_module_filename(StringView filename, StringView module_type)
  711. {
  712. auto extensions = Vector<StringView, 2> { "js"sv, "mjs"sv };
  713. if (module_type == "json"sv)
  714. extensions = { "json"sv };
  715. if (!FileSystem::exists(filename)) {
  716. for (auto extension : extensions) {
  717. // import "./foo" -> import "./foo.ext"
  718. auto resolved_filepath = DeprecatedString::formatted("{}.{}", filename, extension);
  719. if (FileSystem::exists(resolved_filepath))
  720. return resolved_filepath;
  721. }
  722. } else if (FileSystem::is_directory(filename)) {
  723. for (auto extension : extensions) {
  724. // import "./foo" -> import "./foo/index.ext"
  725. auto resolved_filepath = LexicalPath::join(filename, DeprecatedString::formatted("index.{}", extension)).string();
  726. if (FileSystem::exists(resolved_filepath))
  727. return resolved_filepath;
  728. }
  729. }
  730. return filename;
  731. }
  732. // 16.2.1.7 HostResolveImportedModule ( referencingScriptOrModule, specifier ), https://tc39.es/ecma262/#sec-hostresolveimportedmodule
  733. ThrowCompletionOr<NonnullGCPtr<Module>> VM::resolve_imported_module(ScriptOrModule referencing_script_or_module, ModuleRequest const& module_request)
  734. {
  735. // An implementation of HostResolveImportedModule must conform to the following requirements:
  736. // - If it completes normally, the [[Value]] slot of the completion must contain an instance of a concrete subclass of Module Record.
  737. // - If a Module Record corresponding to the pair referencingScriptOrModule, moduleRequest does not exist or cannot be created, an exception must be thrown.
  738. // - Each time this operation is called with a specific referencingScriptOrModule, moduleRequest.[[Specifier]], moduleRequest.[[Assertions]] triple
  739. // as arguments it must return the same Module Record instance if it completes normally.
  740. // * It is recommended but not required that implementations additionally conform to the following stronger constraint:
  741. // each time this operation is called with a specific referencingScriptOrModule, moduleRequest.[[Specifier]] pair as arguments it must return the same Module Record instance if it completes normally.
  742. // - moduleRequest.[[Assertions]] must not influence the interpretation of the module or the module specifier;
  743. // instead, it may be used to determine whether the algorithm completes normally or with an abrupt completion.
  744. // Multiple different referencingScriptOrModule, moduleRequest.[[Specifier]] pairs may map to the same Module Record instance.
  745. // The actual mapping semantic is host-defined but typically a normalization process is applied to specifier as part of the mapping process.
  746. // A typical normalization process would include actions such as alphabetic case folding and expansion of relative and abbreviated path specifiers.
  747. // We only allow "type" as a supported assertion so it is the only valid key that should ever arrive here.
  748. VERIFY(module_request.assertions.is_empty() || (module_request.assertions.size() == 1 && module_request.assertions.first().key == "type"));
  749. auto module_type = module_request.assertions.is_empty() ? DeprecatedString {} : module_request.assertions.first().value;
  750. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] module at {} has type {} [is_null={}]", module_request.module_specifier, module_type, module_type.is_null());
  751. StringView base_filename = referencing_script_or_module.visit(
  752. [&](Empty) {
  753. return "."sv;
  754. },
  755. [&](auto& script_or_module) {
  756. return script_or_module->filename();
  757. });
  758. LexicalPath base_path { base_filename };
  759. auto filename = LexicalPath::absolute_path(base_path.dirname(), module_request.module_specifier);
  760. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] base path: '{}'", base_path);
  761. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] initial filename: '{}'", filename);
  762. filename = resolve_module_filename(filename, module_type);
  763. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] resolved filename: '{}'", filename);
  764. #if JS_MODULE_DEBUG
  765. DeprecatedString referencing_module_string = referencing_script_or_module.visit(
  766. [&](Empty) -> DeprecatedString {
  767. return ".";
  768. },
  769. [&](auto& script_or_module) {
  770. if constexpr (IsSame<Script*, decltype(script_or_module)>) {
  771. return DeprecatedString::formatted("Script @ {}", script_or_module.ptr());
  772. }
  773. return DeprecatedString::formatted("Module @ {}", script_or_module.ptr());
  774. });
  775. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] resolve_imported_module({}, {})", referencing_module_string, filename);
  776. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] resolved {} + {} -> {}", base_path, module_request.module_specifier, filename);
  777. #endif
  778. auto* loaded_module_or_end = get_stored_module(referencing_script_or_module, filename, module_type);
  779. if (loaded_module_or_end != nullptr) {
  780. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] resolve_imported_module({}) already loaded at {}", filename, loaded_module_or_end->module.ptr());
  781. return NonnullGCPtr(*loaded_module_or_end->module);
  782. }
  783. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] reading and parsing module {}", filename);
  784. auto file_or_error = Core::DeprecatedFile::open(filename, Core::OpenMode::ReadOnly);
  785. if (file_or_error.is_error()) {
  786. return throw_completion<SyntaxError>(ErrorType::ModuleNotFound, module_request.module_specifier);
  787. }
  788. // FIXME: Don't read the file in one go.
  789. auto file_content = file_or_error.value()->read_all();
  790. StringView content_view { file_content.data(), file_content.size() };
  791. auto module = TRY([&]() -> ThrowCompletionOr<NonnullGCPtr<Module>> {
  792. // If assertions has an entry entry such that entry.[[Key]] is "type", let type be entry.[[Value]]. The following requirements apply:
  793. // If type is "json", then this algorithm must either invoke ParseJSONModule and return the resulting Completion Record, or throw an exception.
  794. if (module_type == "json"sv) {
  795. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] reading and parsing JSON module {}", filename);
  796. return parse_json_module(content_view, *current_realm(), filename);
  797. }
  798. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] reading and parsing as SourceTextModule module {}", filename);
  799. // Note: We treat all files as module, so if a script does not have exports it just runs it.
  800. auto module_or_errors = SourceTextModule::parse(content_view, *current_realm(), filename);
  801. if (module_or_errors.is_error()) {
  802. VERIFY(module_or_errors.error().size() > 0);
  803. return throw_completion<SyntaxError>(module_or_errors.error().first().to_deprecated_string());
  804. }
  805. return module_or_errors.release_value();
  806. }());
  807. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] resolve_imported_module(...) parsed {} to {}", filename, module.ptr());
  808. // We have to set it here already in case it references itself.
  809. m_loaded_modules.empend(
  810. referencing_script_or_module,
  811. filename,
  812. module_type,
  813. *module,
  814. false);
  815. return module;
  816. }
  817. // 16.2.1.8 HostImportModuleDynamically ( referencingScriptOrModule, specifier, promiseCapability ), https://tc39.es/ecma262/#sec-hostimportmoduledynamically
  818. ThrowCompletionOr<void> VM::import_module_dynamically(ScriptOrModule referencing_script_or_module, ModuleRequest module_request, PromiseCapability const& promise_capability)
  819. {
  820. auto& realm = *current_realm();
  821. // Success path:
  822. // - At some future time, the host environment must perform FinishDynamicImport(referencingScriptOrModule, moduleRequest, promiseCapability, promise),
  823. // where promise is a Promise resolved with undefined.
  824. // - Any subsequent call to HostResolveImportedModule after FinishDynamicImport has completed,
  825. // given the arguments referencingScriptOrModule and specifier, must return a normal completion
  826. // containing a module which has already been evaluated, i.e. whose Evaluate concrete method has
  827. // already been called and returned a normal completion.
  828. // Failure path:
  829. // - At some future time, the host environment must perform
  830. // FinishDynamicImport(referencingScriptOrModule, moduleRequest, promiseCapability, promise),
  831. // where promise is a Promise rejected with an error representing the cause of failure.
  832. auto promise = Promise::create(realm);
  833. ScopeGuard finish_dynamic_import = [&] {
  834. host_finish_dynamic_import(referencing_script_or_module, module_request, promise_capability, promise);
  835. };
  836. // Generally within ECMA262 we always get a referencing_script_or_moulde. However, ShadowRealm gives an explicit null.
  837. // To get around this is we attempt to get the active script_or_module otherwise we might start loading "random" files from the working directory.
  838. if (referencing_script_or_module.has<Empty>()) {
  839. referencing_script_or_module = get_active_script_or_module();
  840. // If there is no ScriptOrModule in any of the execution contexts
  841. if (referencing_script_or_module.has<Empty>()) {
  842. // Throw an error for now
  843. promise->reject(InternalError::create(realm, TRY_OR_THROW_OOM(*this, String::formatted(ErrorType::ModuleNotFoundNoReferencingScript.message(), module_request.module_specifier))));
  844. return {};
  845. }
  846. }
  847. // Note: If host_resolve_imported_module returns a module it has been loaded successfully and the next call in finish_dynamic_import will retrieve it again.
  848. auto module_or_error = host_resolve_imported_module(referencing_script_or_module, module_request);
  849. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] HostImportModuleDynamically(..., {}) -> {}", module_request.module_specifier, module_or_error.is_error() ? "failed" : "passed");
  850. if (module_or_error.is_throw_completion()) {
  851. promise->reject(*module_or_error.throw_completion().value());
  852. } else {
  853. auto module = module_or_error.release_value();
  854. auto& source_text_module = static_cast<Module&>(*module);
  855. auto evaluated_or_error = link_and_eval_module(source_text_module);
  856. if (evaluated_or_error.is_throw_completion()) {
  857. promise->reject(*evaluated_or_error.throw_completion().value());
  858. } else {
  859. promise->fulfill(js_undefined());
  860. }
  861. }
  862. // It must return unused.
  863. // Note: Just return void always since the resulting value cannot be accessed by user code.
  864. return {};
  865. }
  866. // 16.2.1.9 FinishDynamicImport ( referencingScriptOrModule, specifier, promiseCapability, innerPromise ), https://tc39.es/ecma262/#sec-finishdynamicimport
  867. void VM::finish_dynamic_import(ScriptOrModule referencing_script_or_module, ModuleRequest module_request, PromiseCapability const& promise_capability, Promise* inner_promise)
  868. {
  869. dbgln_if(JS_MODULE_DEBUG, "[JS MODULE] finish_dynamic_import on {}", module_request.module_specifier);
  870. auto& realm = *current_realm();
  871. // 1. Let fulfilledClosure be a new Abstract Closure with parameters (result) that captures referencingScriptOrModule, specifier, and promiseCapability and performs the following steps when called:
  872. auto fulfilled_closure = [referencing_script_or_module = move(referencing_script_or_module), module_request = move(module_request), &promise_capability](VM& vm) -> ThrowCompletionOr<Value> {
  873. auto result = vm.argument(0);
  874. // a. Assert: result is undefined.
  875. VERIFY(result.is_undefined());
  876. // b. Let moduleRecord be ! HostResolveImportedModule(referencingScriptOrModule, specifier).
  877. auto module_record = MUST(vm.host_resolve_imported_module(referencing_script_or_module, module_request));
  878. // c. Assert: Evaluate has already been invoked on moduleRecord and successfully completed.
  879. // Note: If HostResolveImportedModule returns a module evaluate will have been called on it.
  880. // d. Let namespace be Completion(GetModuleNamespace(moduleRecord)).
  881. auto namespace_ = module_record->get_module_namespace(vm);
  882. // e. If namespace is an abrupt completion, then
  883. if (namespace_.is_throw_completion()) {
  884. // i. Perform ! Call(promiseCapability.[[Reject]], undefined, « namespace.[[Value]] »).
  885. MUST(call(vm, *promise_capability.reject(), js_undefined(), *namespace_.throw_completion().value()));
  886. }
  887. // f. Else,
  888. else {
  889. // i. Perform ! Call(promiseCapability.[[Resolve]], undefined, « namespace.[[Value]] »).
  890. MUST(call(vm, *promise_capability.resolve(), js_undefined(), namespace_.release_value()));
  891. }
  892. // g. Return unused.
  893. // NOTE: We don't support returning an empty/optional/unused value here.
  894. return js_undefined();
  895. };
  896. // 2. Let onFulfilled be CreateBuiltinFunction(fulfilledClosure, 0, "", « »).
  897. auto on_fulfilled = NativeFunction::create(realm, move(fulfilled_closure), 0, "");
  898. // 3. Let rejectedClosure be a new Abstract Closure with parameters (error) that captures promiseCapability and performs the following steps when called:
  899. auto rejected_closure = [&promise_capability](VM& vm) -> ThrowCompletionOr<Value> {
  900. auto error = vm.argument(0);
  901. // a. Perform ! Call(promiseCapability.[[Reject]], undefined, « error »).
  902. MUST(call(vm, *promise_capability.reject(), js_undefined(), error));
  903. // b. Return unused.
  904. // NOTE: We don't support returning an empty/optional/unused value here.
  905. return js_undefined();
  906. };
  907. // 4. Let onRejected be CreateBuiltinFunction(rejectedClosure, 0, "", « »).
  908. auto on_rejected = NativeFunction::create(realm, move(rejected_closure), 0, "");
  909. // 5. Perform PerformPromiseThen(innerPromise, onFulfilled, onRejected).
  910. inner_promise->perform_then(on_fulfilled, on_rejected, {});
  911. // 6. Return unused.
  912. }
  913. }