ladybird/Userland/Libraries/LibJS/Runtime/ShadowRealm.cpp

280 lines
13 KiB
C++

/*
* Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <LibJS/Lexer.h>
#include <LibJS/Parser.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/DeclarativeEnvironment.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/PromiseConstructor.h>
#include <LibJS/Runtime/PromiseReaction.h>
#include <LibJS/Runtime/ShadowRealm.h>
#include <LibJS/Runtime/WrappedFunction.h>
namespace JS {
ShadowRealm::ShadowRealm(Realm& shadow_realm, ExecutionContext execution_context, Object& prototype)
: Object(prototype)
, m_shadow_realm(shadow_realm)
, m_execution_context(move(execution_context))
{
}
void ShadowRealm::visit_edges(Visitor& visitor)
{
Base::visit_edges(visitor);
visitor.visit(&m_shadow_realm);
}
// 3.1.1 PerformShadowRealmEval ( sourceText, callerRealm, evalRealm ), https://tc39.es/proposal-shadowrealm/#sec-performshadowrealmeval
ThrowCompletionOr<Value> perform_shadow_realm_eval(GlobalObject& global_object, StringView source_text, Realm& caller_realm, Realm& eval_realm)
{
auto& vm = global_object.vm();
// 1. Assert: Type(sourceText) is String.
// 2. Assert: callerRealm is a Realm Record.
// 3. Assert: evalRealm is a Realm Record.
// 4. Perform ? HostEnsureCanCompileStrings(callerRealm, evalRealm).
// FIXME: We don't have this host-defined abstract operation yet.
// 5. Perform the following substeps in an implementation-defined order, possibly interleaving parsing and error detection:
// a. Let script be ParseText(! StringToCodePoints(sourceText), Script).
auto parser = Parser(Lexer(source_text));
auto program = parser.parse_program();
// b. If script is a List of errors, throw a SyntaxError exception.
if (parser.has_errors()) {
auto& error = parser.errors()[0];
return vm.throw_completion<JS::SyntaxError>(global_object, error.to_string());
}
// c. If script Contains ScriptBody is false, return undefined.
if (program->children().is_empty())
return js_undefined();
// d. Let body be the ScriptBody of script.
// e. If body Contains NewTarget is true, throw a SyntaxError exception.
// f. If body Contains SuperProperty is true, throw a SyntaxError exception.
// g. If body Contains SuperCall is true, throw a SyntaxError exception.
// FIXME: Implement these, we probably need a generic way of scanning the AST for certain nodes.
// 6. Let strictEval be IsStrict of script.
auto strict_eval = program->is_strict_mode();
// 7. Let runningContext be the running execution context.
// NOTE: This would be unused due to step 11 and is omitted for that reason.
// 8. Let lexEnv be NewDeclarativeEnvironment(evalRealm.[[GlobalEnv]]).
Environment* lexical_environment = new_declarative_environment(eval_realm.global_environment());
// 9. Let varEnv be evalRealm.[[GlobalEnv]].
Environment* variable_environment = &eval_realm.global_environment();
// 10. If strictEval is true, set varEnv to lexEnv.
if (strict_eval)
variable_environment = lexical_environment;
// 11. If runningContext is not already suspended, suspend runningContext.
// NOTE: We don't support this concept yet.
// 12. Let evalContext be a new ECMAScript code execution context.
auto eval_context = ExecutionContext { vm.heap() };
// 13. Set evalContext's Function to null.
eval_context.function = nullptr;
// 14. Set evalContext's Realm to evalRealm.
eval_context.realm = &eval_realm;
// 15. Set evalContext's ScriptOrModule to null.
// FIXME: Our execution context struct currently does not track this item.
// 16. Set evalContext's VariableEnvironment to varEnv.
eval_context.variable_environment = variable_environment;
// 17. Set evalContext's LexicalEnvironment to lexEnv.
eval_context.lexical_environment = lexical_environment;
// Non-standard
eval_context.is_strict_mode = strict_eval;
// 18. Push evalContext onto the execution context stack; evalContext is now the running execution context.
TRY(vm.push_execution_context(eval_context, eval_realm.global_object()));
// 19. Let result be EvalDeclarationInstantiation(body, varEnv, lexEnv, null, strictEval).
auto eval_result = eval_declaration_instantiation(vm, eval_realm.global_object(), program, variable_environment, lexical_environment, nullptr, strict_eval);
Completion result;
// 20. If result.[[Type]] is normal, then
if (!eval_result.is_throw_completion()) {
// TODO: Optionally use bytecode interpreter?
// FIXME: We need to use evaluate_statements() here because Program::execute() calls global_declaration_instantiation() when it shouldn't
// a. Set result to the result of evaluating body.
auto result_value = program->evaluate_statements(vm.interpreter(), eval_realm.global_object());
if (auto* exception = vm.exception())
result = throw_completion(exception->value());
else if (!result_value.is_empty())
result = normal_completion(result_value);
else
result = Completion {}; // Normal completion with no value
}
// 21. If result.[[Type]] is normal and result.[[Value]] is empty, then
if (result.type() == Completion::Type::Normal && !result.has_value()) {
// a. Set result to NormalCompletion(undefined).
result = normal_completion(js_undefined());
}
// 22. Suspend evalContext and remove it from the execution context stack.
// NOTE: We don't support this concept yet.
vm.pop_execution_context();
// 23. Resume the context that is now on the top of the execution context stack as the running execution context.
// NOTE: We don't support this concept yet.
// 24. If result.[[Type]] is not normal, throw a TypeError exception.
if (result.type() != Completion::Type::Normal)
return vm.throw_completion<TypeError>(global_object, ErrorType::ShadowRealmEvaluateAbruptCompletion);
// 25. Return ? GetWrappedValue(callerRealm, result.[[Value]]).
return get_wrapped_value(global_object, caller_realm, result.value());
// NOTE: Also see "Editor's Note" in the spec regarding the TypeError above.
}
// 3.1.2 ShadowRealmImportValue ( specifierString, exportNameString, callerRealm, evalRealm, evalContext ), https://tc39.es/proposal-shadowrealm/#sec-shadowrealmimportvalue
ThrowCompletionOr<Value> shadow_realm_import_value(GlobalObject& global_object, String specifier_string, String export_name_string, Realm& caller_realm, Realm& eval_realm, ExecutionContext& eval_context)
{
auto& vm = global_object.vm();
// 1. Assert: Type(specifierString) is String.
// 2. Assert: Type(exportNameString) is String.
// 3. Assert: callerRealm is a Realm Record.
// 4. Assert: evalRealm is a Realm Record.
// 5. Assert: evalContext is an execution context associated to a ShadowRealm instance's [[ExecutionContext]].
// 6. Let innerCapability be ! NewPromiseCapability(%Promise%).
auto inner_capability = MUST(new_promise_capability(global_object, global_object.promise_constructor()));
// 7. Let runningContext be the running execution context.
// 8. If runningContext is not already suspended, suspend runningContext.
// NOTE: We don't support this concept yet.
// 9. Push evalContext onto the execution context stack; evalContext is now the running execution context.
TRY(vm.push_execution_context(eval_context, eval_realm.global_object()));
// 10. Perform ! HostImportModuleDynamically(null, specifierString, innerCapability).
// FIXME: We don't have this yet. We generally have very little support for modules and imports.
// So, in the meantime we just do the "Failure path" step, and pretend to call FinishDynamicImport
// with the rejected promise. This should be easy to complete once those missing module AOs are added.
// HostImportModuleDynamically: At some future time, the host environment must perform
// FinishDynamicImport(referencingScriptOrModule, specifier, promiseCapability, promise),
// where promise is a Promise rejected with an error representing the cause of failure.
auto* promise = Promise::create(global_object);
promise->reject(Error::create(global_object, String::formatted("Import of '{}' from '{}' failed", export_name_string, specifier_string)));
// FinishDynamicImport, 5. Perform ! PerformPromiseThen(innerPromise, onFulfilled, onRejected).
promise->perform_then(
NativeFunction::create(global_object, "", [](auto&, auto&) -> ThrowCompletionOr<Value> {
// Not called because we hardcoded a rejection above.
TODO();
}),
NativeFunction::create(global_object, "", [reject = make_handle(inner_capability.reject)](auto& vm, auto& global_object) -> ThrowCompletionOr<Value> {
auto error = vm.argument(0);
// a. Perform ! Call(promiseCapability.[[Reject]], undefined, « error »).
MUST(call(global_object, reject.cell(), js_undefined(), error));
// b. Return undefined.
return js_undefined();
}),
{});
// 11. Suspend evalContext and remove it from the execution context stack.
// NOTE: We don't support this concept yet.
vm.pop_execution_context();
// 12. Resume the context that is now on the top of the execution context stack as the running execution context.
// NOTE: We don't support this concept yet.
// 13. Let steps be the steps of an ExportGetter function as described below.
// 14. Let onFulfilled be ! CreateBuiltinFunction(steps, 1, "", « [[ExportNameString]] », callerRealm).
// 15. Set onFulfilled.[[ExportNameString]] to exportNameString.
// FIXME: Support passing a realm to NativeFunction::create()
(void)caller_realm;
auto* on_fulfilled = NativeFunction::create(
global_object,
"",
[string = move(export_name_string)](auto& vm, auto& global_object) -> ThrowCompletionOr<Value> {
// 1. Assert: exports is a module namespace exotic object.
auto& exports = vm.argument(0).as_object();
// 2. Let f be the active function object.
auto* function = vm.running_execution_context().function;
// 3. Let string be f.[[ExportNameString]].
// 4. Assert: Type(string) is String.
// 5. Let hasOwn be ? HasOwnProperty(exports, string).
auto has_own = TRY(exports.has_own_property(string));
// 6. If hasOwn is false, throw a TypeError exception.
if (!has_own)
return vm.template throw_completion<TypeError>(global_object, ErrorType::MissingRequiredProperty, string);
// 7. Let value be ? Get(exports, string).
auto value = TRY(exports.get(string));
// 8. Let realm be f.[[Realm]].
auto* realm = function->realm();
VERIFY(realm);
// 9. Return ? GetWrappedValue(realm, value).
return get_wrapped_value(global_object, *realm, value);
});
on_fulfilled->define_direct_property(vm.names.length, Value(1), Attribute::Configurable);
on_fulfilled->define_direct_property(vm.names.name, js_string(vm, String::empty()), Attribute::Configurable);
// 16. Let promiseCapability be ! NewPromiseCapability(%Promise%).
auto promise_capability = MUST(new_promise_capability(global_object, global_object.promise_constructor()));
// NOTE: Even though the spec tells us to use %ThrowTypeError%, it's not observable if we actually do.
// Throw a nicer TypeError forwarding the import error message instead (we know the argument is an Error object).
auto* throw_type_error = NativeFunction::create(global_object, {}, [](auto& vm, auto& global_object) -> ThrowCompletionOr<Value> {
return vm.template throw_completion<TypeError>(global_object, vm.argument(0).as_object().get_without_side_effects(vm.names.message).as_string().string());
});
// 17. Return ! PerformPromiseThen(innerCapability.[[Promise]], onFulfilled, callerRealm.[[Intrinsics]].[[%ThrowTypeError%]], promiseCapability).
return verify_cast<Promise>(inner_capability.promise)->perform_then(on_fulfilled, throw_type_error, promise_capability);
}
// 3.1.3 GetWrappedValue ( callerRealm, value ), https://tc39.es/proposal-shadowrealm/#sec-getwrappedvalue
ThrowCompletionOr<Value> get_wrapped_value(GlobalObject& global_object, Realm& caller_realm, Value value)
{
auto& vm = global_object.vm();
// 1. Assert: callerRealm is a Realm Record.
// 2. If Type(value) is Object, then
if (value.is_object()) {
// a. If IsCallable(value) is false, throw a TypeError exception.
if (!value.is_function())
return vm.throw_completion<TypeError>(global_object, ErrorType::ShadowRealmWrappedValueNonFunctionObject, value);
// b. Return ! WrappedFunctionCreate(callerRealm, value).
return WrappedFunction::create(global_object, caller_realm, value.as_function());
}
// 3. Return value.
return value;
}
}