LadybirdBrowser/ladybird
1
1
Fork 0
mirror of https://github.com/LadybirdBrowser/ladybird.git synced 2024-10-05 17:49:16 +03:00
Code Issues Packages Projects Releases Wiki Activity

LibJS: Add using declaration support, RAII like operation in js

Browse Source 
In this patch only top level and not the more complicated for loop using
statements are supported. Also, as noted in the latest meeting of tc39
async parts of the spec are not stage 3 thus not included.
This commit is contained in:
davidot 2022-12-20 22:09:57 +01:00 committed by Linus Groh
parent 2c87ff2218
commit 541637e15a
Notes: sideshowbarker 2024-07-17 01:21:46 +09:00 
Author: https://github.com/davidot
Commit: https://github.com/SerenityOS/serenity/commit/541637e15a
Pull-request: https://github.com/SerenityOS/serenity/pull/16630
Reviewed-by: https://github.com/alimpfard
Reviewed-by: https://github.com/linusg ✅
15 changed files with 861 additions and 68 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
.prettierignore
View File

@ -2,3 +2,7 @@ Base/home/anon/Source/js
Userland/Libraries/LibJS/Tests/invalid-lhs-in-assignment.js
Userland/Libraries/LibJS/Tests/unicode-identifier-escape.js
Userland/Libraries/LibJS/Tests/modules/failing.mjs
# FIXME: Remove once prettier is updated to support using declarations.
Userland/Libraries/LibJS/Tests/modules/top-level-dispose.mjs
Userland/Libraries/LibJS/Tests/using-declaration.js

98
Userland/Libraries/LibJS/AST.cpp
View File

@ -235,21 +235,25 @@ Completion BlockStatement::execute(Interpreter& interpreter) const
auto& vm = interpreter.vm();
Environment* old_environment { nullptr };
ArmedScopeGuard restore_environment = [&] {
vm.running_execution_context().lexical_environment = old_environment;
};
// Optimization: We only need a new lexical environment if there are any lexical declarations. :^)
if (has_lexical_declarations()) {
old_environment = vm.running_execution_context().lexical_environment;
auto block_environment = new_declarative_environment(*old_environment);
block_declaration_instantiation(interpreter, block_environment);
vm.running_execution_context().lexical_environment = block_environment;
} else {
restore_environment.disarm();
}
if (!has_lexical_declarations())
return evaluate_statements(interpreter);
return evaluate_statements(interpreter);
old_environment = vm.running_execution_context().lexical_environment;
auto block_environment = new_declarative_environment(*old_environment);
block_declaration_instantiation(interpreter, block_environment);
vm.running_execution_context().lexical_environment = block_environment;
// 5. Let blockValue be the result of evaluating StatementList.
auto block_value = evaluate_statements(interpreter);
// 6. Set blockValue to DisposeResources(blockEnv, blockValue).
block_value = dispose_resources(vm, block_environment, block_value);
vm.running_execution_context().lexical_environment = old_environment;
return block_value;
}
Completion Program::execute(Interpreter& interpreter) const
@ -3015,6 +3019,48 @@ void VariableDeclaration::dump(int indent) const
declarator.dump(indent + 1);
}
// 6.2.1.2 Runtime Semantics: Evaluation, https://tc39.es/proposal-explicit-resource-management/#sec-let-and-const-declarations-runtime-semantics-evaluation
Completion UsingDeclaration::execute(Interpreter& interpreter) const
{
// 1. Let next be BindingEvaluation of BindingList with parameter sync-dispose.
InterpreterNodeScope node_scope { interpreter, *this };
auto& vm = interpreter.vm();
for (auto& declarator : m_declarations) {
VERIFY(declarator.target().has<NonnullRefPtr<Identifier>>());
VERIFY(declarator.init());
auto& id = declarator.target().get<NonnullRefPtr<Identifier>>();
// 2. ReturnIfAbrupt(next).
auto reference = TRY(id->to_reference(interpreter));
auto initializer_result = TRY(interpreter.vm().named_evaluation_if_anonymous_function(*declarator.init(), id->string()));
VERIFY(!initializer_result.is_empty());
TRY(reference.initialize_referenced_binding(vm, initializer_result, Environment::InitializeBindingHint::SyncDispose));
}
// 3. Return empty.
return normal_completion({});
}
ThrowCompletionOr<void> UsingDeclaration::for_each_bound_name(ThrowCompletionOrVoidCallback<DeprecatedFlyString const&>&& callback) const
{
for (auto const& entry : m_declarations) {
VERIFY(entry.target().has<NonnullRefPtr<Identifier>>());
TRY(callback(entry.target().get<NonnullRefPtr<Identifier>>()->string()));
}
return {};
}
void UsingDeclaration::dump(int indent) const
{
ASTNode::dump(indent);
print_indent(indent + 1);
for (auto& declarator : m_declarations)
declarator.dump(indent + 1);
}
void VariableDeclarator::dump(int indent) const
{
ASTNode::dump(indent);
@ -4154,11 +4200,13 @@ Completion SwitchStatement::execute_impl(Interpreter& interpreter) const
// 2. Let switchValue be ? GetValue(exprRef).
auto switch_value = TRY(m_discriminant->execute(interpreter)).release_value();
// 3. Let oldEnv be the running execution context's LexicalEnvironment.
auto* old_environment = interpreter.lexical_environment();
Completion result;
// Optimization: Avoid creating a lexical environment if there are no lexical declarations.
if (has_lexical_declarations()) {
// 3. Let oldEnv be the running execution context's LexicalEnvironment.
auto* old_environment = interpreter.lexical_environment();
// 4. Let blockEnv be NewDeclarativeEnvironment(oldEnv).
auto block_environment = new_declarative_environment(*old_environment);
@ -4167,15 +4215,23 @@ Completion SwitchStatement::execute_impl(Interpreter& interpreter) const
// 6. Set the running execution context's LexicalEnvironment to blockEnv.
vm.running_execution_context().lexical_environment = block_environment;
// 7. Let R be Completion(CaseBlockEvaluation of CaseBlock with argument switchValue).
result = case_block_evaluation(switch_value);
// 8. Let env be blockEnv's LexicalEnvironment.
// FIXME: blockEnv doesn't have a lexical env it is one?? Probably a spec issue
// 9. Set R to DisposeResources(env, R).
result = dispose_resources(vm, block_environment, result);
// 10. Set the running execution context's LexicalEnvironment to oldEnv.
vm.running_execution_context().lexical_environment = old_environment;
} else {
result = case_block_evaluation(switch_value);
}
// 7. Let R be Completion(CaseBlockEvaluation of CaseBlock with argument switchValue).
auto result = case_block_evaluation(switch_value);
// 8. Set the running execution context's LexicalEnvironment to oldEnv.
vm.running_execution_context().lexical_environment = old_environment;
// 9. Return R.
// 11. Return R.
return result;
}

21
Userland/Libraries/LibJS/AST.h
View File

@ -1719,6 +1719,27 @@ private:
NonnullRefPtrVector<VariableDeclarator> m_declarations;
};
class UsingDeclaration final : public Declaration {
public:
UsingDeclaration(SourceRange source_range, NonnullRefPtrVector<VariableDeclarator> declarations)
: Declaration(move(source_range))
, m_declarations(move(declarations))
{
}
virtual Completion execute(Interpreter&) const override;
virtual void dump(int indent) const override;
virtual ThrowCompletionOr<void> for_each_bound_name(ThrowCompletionOrVoidCallback<DeprecatedFlyString const&>&& callback) const override;
virtual bool is_constant_declaration() const override { return true; };
virtual bool is_lexical_declaration() const override { return true; }
private:
NonnullRefPtrVector<VariableDeclarator> m_declarations;
};
class ObjectProperty final : public ASTNode {
public:
enum class Type : u8 {

156
Userland/Libraries/LibJS/Parser.cpp
View File

@ -253,6 +253,11 @@ public:
return m_contains_await_expression;
}
bool can_have_using_declaration() const
{
return m_scope_level != ScopeLevel::ScriptTopLevel;
}
private:
void throw_identifier_declared(DeprecatedFlyString const& name, NonnullRefPtr<Declaration> const& declaration)
{
@ -597,6 +602,14 @@ NonnullRefPtr<Declaration> Parser::parse_declaration()
case TokenType::Let:
case TokenType::Const:
return parse_variable_declaration();
case TokenType::Identifier:
if (m_state.current_token.original_value() == "using"sv) {
if (!m_state.current_scope_pusher->can_have_using_declaration())
syntax_error("'using' not allowed outside of block, for loop or function");
return parse_using_declaration();
}
[[fallthrough]];
default:
expected("declaration");
consume();
@ -2457,7 +2470,7 @@ NonnullRefPtr<ReturnStatement> Parser::parse_return_statement()
void Parser::parse_statement_list(ScopeNode& output_node, AllowLabelledFunction allow_labelled_functions)
{
while (!done()) {
if (match_declaration()) {
if (match_declaration(AllowUsingDeclaration::Yes)) {
auto declaration = parse_declaration();
VERIFY(m_state.current_scope_pusher);
m_state.current_scope_pusher->add_declaration(declaration);
@ -2949,7 +2962,37 @@ RefPtr<BindingPattern> Parser::parse_binding_pattern(Parser::AllowDuplicates all
return pattern;
}
NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_loop_variable_declaration)
RefPtr<Identifier> Parser::parse_lexical_binding()
{
auto binding_start = push_start();
if (match_identifier()) {
auto name = consume_identifier().DeprecatedFlyString_value();
return create_ast_node<Identifier>(
{ m_source_code, binding_start.position(), position() },
name);
}
if (!m_state.in_generator_function_context && match(TokenType::Yield)) {
if (m_state.strict_mode)
syntax_error("Identifier must not be a reserved word in strict mode ('yield')");
return create_ast_node<Identifier>(
{ m_source_code, binding_start.position(), position() },
consume().DeprecatedFlyString_value());
}
if (!m_state.await_expression_is_valid && match(TokenType::Async)) {
if (m_program_type == Program::Type::Module)
syntax_error("Identifier must not be a reserved word in modules ('async')");
return create_ast_node<Identifier>(
{ m_source_code, binding_start.position(), position() },
consume().DeprecatedFlyString_value());
}
return {};
}
NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(IsForLoopVariableDeclaration is_for_loop_variable_declaration)
{
auto rule_start = push_start();
DeclarationKind declaration_kind;
@ -2972,38 +3015,21 @@ NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_l
NonnullRefPtrVector<VariableDeclarator> declarations;
for (;;) {
Variant<NonnullRefPtr<Identifier>, NonnullRefPtr<BindingPattern>, Empty> target {};
if (match_identifier()) {
auto identifier_start = push_start();
auto name = consume_identifier().DeprecatedFlyString_value();
target = create_ast_node<Identifier>(
{ m_source_code, rule_start.position(), position() },
name);
check_identifier_name_for_assignment_validity(name);
if ((declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const) && name == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
} else if (auto pattern = parse_binding_pattern(declaration_kind != DeclarationKind::Var ? AllowDuplicates::No : AllowDuplicates::Yes, AllowMemberExpressions::No)) {
target = pattern.release_nonnull();
if (auto pattern = parse_binding_pattern(declaration_kind != DeclarationKind::Var ? AllowDuplicates::No : AllowDuplicates::Yes, AllowMemberExpressions::No)) {
if ((declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const)) {
target.get<NonnullRefPtr<BindingPattern>>()->for_each_bound_name([this](auto& name) {
pattern->for_each_bound_name([this](auto& name) {
if (name == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
});
}
} else if (!m_state.in_generator_function_context && match(TokenType::Yield)) {
if (m_state.strict_mode)
syntax_error("Identifier must not be a reserved word in strict mode ('yield')");
target = create_ast_node<Identifier>(
{ m_source_code, rule_start.position(), position() },
consume().DeprecatedFlyString_value());
} else if (!m_state.await_expression_is_valid && match(TokenType::Async)) {
if (m_program_type == Program::Type::Module)
syntax_error("Identifier must not be a reserved word in modules ('async')");
target = pattern.release_nonnull();
} else if (auto lexical_binding = parse_lexical_binding()) {
check_identifier_name_for_assignment_validity(lexical_binding->string());
if ((declaration_kind == DeclarationKind::Let || declaration_kind == DeclarationKind::Const) && lexical_binding->string() == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
target = create_ast_node<Identifier>(
{ m_source_code, rule_start.position(), position() },
consume().DeprecatedFlyString_value());
target = lexical_binding.release_nonnull();
}
if (target.has<Empty>()) {
@ -3020,13 +3046,13 @@ NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_l
consume();
// In a for loop 'in' can be ambiguous so we do not allow it
// 14.7.4 The for Statement, https://tc39.es/ecma262/#prod-ForStatement and 14.7.5 The for-in, for-of, and for-await-of Statements, https://tc39.es/ecma262/#prod-ForInOfStatement
if (for_loop_variable_declaration)
if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::Yes)
init = parse_expression(2, Associativity::Right, { TokenType::In });
else
init = parse_expression(2);
} else if (!for_loop_variable_declaration && declaration_kind == DeclarationKind::Const) {
} else if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::No && declaration_kind == DeclarationKind::Const) {
syntax_error("Missing initializer in 'const' variable declaration");
} else if (!for_loop_variable_declaration && target.has<NonnullRefPtr<BindingPattern>>()) {
} else if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::No && target.has<NonnullRefPtr<BindingPattern>>()) {
syntax_error("Missing initializer in destructuring assignment");
}
@ -3041,7 +3067,7 @@ NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_l
}
break;
}
if (!for_loop_variable_declaration)
if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::No)
consume_or_insert_semicolon();
declarations.shrink_to_fit();
@ -3050,6 +3076,55 @@ NonnullRefPtr<VariableDeclaration> Parser::parse_variable_declaration(bool for_l
return declaration;
}
NonnullRefPtr<UsingDeclaration> Parser::parse_using_declaration(IsForLoopVariableDeclaration is_for_loop_variable_declaration)
{
// using [no LineTerminator here] BindingList[?In, ?Yield, ?Await, +Using] ;
auto rule_start = push_start();
VERIFY(m_state.current_token.original_value() == "using"sv);
consume(TokenType::Identifier);
VERIFY(!m_state.current_token.trivia_contains_line_terminator());
NonnullRefPtrVector<VariableDeclarator> declarations;
for (;;) {
auto lexical_binding = parse_lexical_binding();
if (!lexical_binding) {
expected("lexical binding");
break;
}
check_identifier_name_for_assignment_validity(lexical_binding->string());
if (lexical_binding->string() == "let"sv)
syntax_error("Lexical binding may not be called 'let'");
RefPtr<Expression> initializer;
if (match(TokenType::Equals)) {
consume();
if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::Yes)
initializer = parse_expression(2, Associativity::Right, { TokenType::In });
else
initializer = parse_expression(2);
} else if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::No) {
consume(TokenType::Equals);
}
declarations.append(create_ast_node<VariableDeclarator>(
{ m_source_code, rule_start.position(), position() },
lexical_binding.release_nonnull(),
move(initializer)));
if (match(TokenType::Comma)) {
consume();
continue;
}
break;
}
if (is_for_loop_variable_declaration == IsForLoopVariableDeclaration::No)
consume_or_insert_semicolon();
return create_ast_node<UsingDeclaration>({ m_source_code, rule_start.position(), position() }, move(declarations));
}
NonnullRefPtr<ThrowStatement> Parser::parse_throw_statement()
{
auto rule_start = push_start();
@ -3499,7 +3574,7 @@ NonnullRefPtr<Statement> Parser::parse_for_statement()
RefPtr<ASTNode> init;
if (!match(TokenType::Semicolon)) {
if (match_variable_declaration()) {
auto declaration = parse_variable_declaration(true);
auto declaration = parse_variable_declaration(IsForLoopVariableDeclaration::Yes);
if (declaration->declaration_kind() == DeclarationKind::Var) {
m_state.current_scope_pusher->add_declaration(declaration);
} else {
@ -3763,7 +3838,7 @@ bool Parser::match_export_or_import() const
|| type == TokenType::Import;
}
bool Parser::match_declaration() const
bool Parser::match_declaration(AllowUsingDeclaration allow_using) const
{
auto type = m_state.current_token.type();
@ -3776,6 +3851,9 @@ bool Parser::match_declaration() const
return lookahead_token.type() == TokenType::Function && !lookahead_token.trivia_contains_line_terminator();
}
if (allow_using == AllowUsingDeclaration::Yes && type == TokenType::Identifier && m_state.current_token.original_value() == "using"sv)
return try_match_using_declaration();
return type == TokenType::Function
|| type == TokenType::Class
|| type == TokenType::Const
@ -3810,6 +3888,18 @@ bool Parser::try_match_let_declaration() const
return false;
}
bool Parser::try_match_using_declaration() const
{
VERIFY(m_state.current_token.type() == TokenType::Identifier);
VERIFY(m_state.current_token.original_value() == "using"sv);
auto token_after = next_token();
if (token_after.trivia_contains_line_terminator())
return false;
return token_after.is_identifier_name();
}
bool Parser::match_variable_declaration() const
{
auto type = m_state.current_token.type();

19
Userland/Libraries/LibJS/Parser.h
View File

@ -88,7 +88,15 @@ public:
NonnullRefPtr<BlockStatement> parse_block_statement();
NonnullRefPtr<FunctionBody> parse_function_body(Vector<FunctionParameter> const& parameters, FunctionKind function_kind, bool& contains_direct_call_to_eval);
NonnullRefPtr<ReturnStatement> parse_return_statement();
NonnullRefPtr<VariableDeclaration> parse_variable_declaration(bool for_loop_variable_declaration = false);
enum class IsForLoopVariableDeclaration {
No,
Yes
};
NonnullRefPtr<VariableDeclaration> parse_variable_declaration(IsForLoopVariableDeclaration is_for_loop_variable_declaration = IsForLoopVariableDeclaration::No);
RefPtr<Identifier> parse_lexical_binding();
NonnullRefPtr<UsingDeclaration> parse_using_declaration(IsForLoopVariableDeclaration is_for_loop_variable_declaration = IsForLoopVariableDeclaration::No);
NonnullRefPtr<Statement> parse_for_statement();
enum class IsForAwaitLoop {
@ -208,8 +216,15 @@ private:
bool match_statement() const;
bool match_export_or_import() const;
bool match_assert_clause() const;
bool match_declaration() const;
enum class AllowUsingDeclaration {
No,
Yes
};
bool match_declaration(AllowUsingDeclaration allow_using = AllowUsingDeclaration::No) const;
bool try_match_let_declaration() const;
bool try_match_using_declaration() const;
bool match_variable_declaration() const;
bool match_identifier() const;
bool match_identifier_name() const;

157
Userland/Libraries/LibJS/Runtime/AbstractOperations.cpp
View File

@ -31,6 +31,7 @@
#include <LibJS/Runtime/PropertyKey.h>
#include <LibJS/Runtime/ProxyObject.h>
#include <LibJS/Runtime/Reference.h>
#include <LibJS/Runtime/SuppressedError.h>
namespace JS {
@ -1316,4 +1317,160 @@ ThrowCompletionOr<String> get_substitution(VM& vm, Utf16View const& matched, Utf
return TRY_OR_THROW_OOM(vm, Utf16View { result }.to_utf8());
}
// 2.1.2 AddDisposableResource ( disposable, V, hint [ , method ] ), https://tc39.es/proposal-explicit-resource-management/#sec-adddisposableresource-disposable-v-hint-disposemethod
ThrowCompletionOr<void> add_disposable_resource(VM& vm, Vector<DisposableResource>& disposable, Value value, Environment::InitializeBindingHint hint, FunctionObject* method)
{
// NOTE: For now only sync is a valid hint
VERIFY(hint == Environment::InitializeBindingHint::SyncDispose);
Optional<DisposableResource> resource;
// 1. If method is not present then,
if (!method) {
// a. If V is null or undefined, return NormalCompletion(empty).
if (value.is_nullish())
return {};
// b. If Type(V) is not Object, throw a TypeError exception.
if (!value.is_object())
return vm.throw_completion<TypeError>(ErrorType::NotAnObject, value.to_string_without_side_effects());
// c. Let resource be ? CreateDisposableResource(V, hint).
resource = TRY(create_disposable_resource(vm, value, hint));
}
// 2. Else,
else {
// a. If V is null or undefined, then
if (value.is_nullish()) {
// i. Let resource be ? CreateDisposableResource(undefined, hint, method).
resource = TRY(create_disposable_resource(vm, js_undefined(), hint, method));
}
// b. Else,
else {
// i. If Type(V) is not Object, throw a TypeError exception.
if (!value.is_object())
return vm.throw_completion<TypeError>(ErrorType::NotAnObject, value.to_string_without_side_effects());
// ii. Let resource be ? CreateDisposableResource(V, hint, method).
resource = TRY(create_disposable_resource(vm, value, hint, method));
}
}
// 3. Append resource to disposable.[[DisposableResourceStack]].
VERIFY(resource.has_value());
disposable.append(resource.release_value());
// 4. Return NormalCompletion(empty).
return {};
}
// 2.1.3 CreateDisposableResource ( V, hint [ , method ] ), https://tc39.es/proposal-explicit-resource-management/#sec-createdisposableresource
ThrowCompletionOr<DisposableResource> create_disposable_resource(VM& vm, Value value, Environment::InitializeBindingHint hint, FunctionObject* method)
{
// 1. If method is not present, then
if (!method) {
// a. If V is undefined, throw a TypeError exception.
if (value.is_undefined())
return vm.throw_completion<TypeError>(ErrorType::IsUndefined, "value");
// b. Set method to ? GetDisposeMethod(V, hint).
method = TRY(get_dispose_method(vm, value, hint));
// c. If method is undefined, throw a TypeError exception.
if (!method)
return vm.throw_completion<TypeError>(ErrorType::NoDisposeMethod, value.to_string_without_side_effects());
}
// 2. Else,
// a. If IsCallable(method) is false, throw a TypeError exception.
// NOTE: This is guaranteed to never occur from the type.
VERIFY(method);
// 3. Return the DisposableResource Record { [[ResourceValue]]: V, [[Hint]]: hint, [[DisposeMethod]]: method }.
// NOTE: Since we only support sync dispose we don't store the hint for now.
VERIFY(hint == Environment::InitializeBindingHint::SyncDispose);
return DisposableResource {
value,
*method
};
}
// 2.1.4 GetDisposeMethod ( V, hint ), https://tc39.es/proposal-explicit-resource-management/#sec-getdisposemethod
ThrowCompletionOr<GCPtr<FunctionObject>> get_dispose_method(VM& vm, Value value, Environment::InitializeBindingHint hint)
{
// NOTE: We only have sync dispose for now which means we ignore step 1.
VERIFY(hint == Environment::InitializeBindingHint::SyncDispose);
// 2. Else,
// a. Let method be ? GetMethod(V, @@dispose).
return GCPtr<FunctionObject> { TRY(value.get_method(vm, *vm.well_known_symbol_dispose())) };
}
// 2.1.5 Dispose ( V, hint, method ), https://tc39.es/proposal-explicit-resource-management/#sec-dispose
Completion dispose(VM& vm, Value value, NonnullGCPtr<FunctionObject> method)
{
// 1. Let result be ? Call(method, V).
[[maybe_unused]] auto result = TRY(call(vm, *method, value));
// NOTE: Hint can only be sync-dispose so we ignore step 2.
// 2. If hint is async-dispose and result is not undefined, then
// a. Perform ? Await(result).
// 3. Return undefined.
return js_undefined();
}
// 2.1.6 DisposeResources ( disposable, completion ), https://tc39.es/proposal-explicit-resource-management/#sec-disposeresources-disposable-completion-errors
Completion dispose_resources(VM& vm, Vector<DisposableResource> const& disposable, Completion completion)
{
// 1. If disposable is not undefined, then
// NOTE: At this point disposable is always defined.
// a. For each resource of disposable.[[DisposableResourceStack]], in reverse list order, do
for (auto const& resource : disposable.in_reverse()) {
// i. Let result be Dispose(resource.[[ResourceValue]], resource.[[Hint]], resource.[[DisposeMethod]]).
auto result = dispose(vm, resource.resource_value, resource.dispose_method);
// ii. If result.[[Type]] is throw, then
if (result.is_error()) {
// 1. If completion.[[Type]] is throw, then
if (completion.is_error()) {
// a. Set result to result.[[Value]].
// b. Let suppressed be completion.[[Value]].
auto suppressed = completion.value().value();
// c. Let error be a newly created SuppressedError object.
auto error = SuppressedError::create(*vm.current_realm());
// d. Perform ! DefinePropertyOrThrow(error, "error", PropertyDescriptor { [[Configurable]]: true, [[Enumerable]]: false, [[Writable]]: true, [[Value]]: result }).
MUST(error->define_property_or_throw(vm.names.error, { .value = result.value(), .writable = true, .enumerable = true, .configurable = true }));
// e. Perform ! DefinePropertyOrThrow(error, "suppressed", PropertyDescriptor { [[Configurable]]: true, [[Enumerable]]: false, [[Writable]]: true, [[Value]]: suppressed }).
MUST(error->define_property_or_throw(vm.names.suppressed, { .value = suppressed, .writable = true, .enumerable = false, .configurable = true }));
// f. Set completion to ThrowCompletion(error).
completion = throw_completion(error);
}
// 2. Else,
else {
// a. Set completion to result.
completion = result;
}
}
}
// 2. Return completion.
return completion;
}
Completion dispose_resources(VM& vm, GCPtr<DeclarativeEnvironment> disposable, Completion completion)
{
// 1. If disposable is not undefined, then
if (disposable)
return dispose_resources(vm, disposable->disposable_resource_stack(), completion);
// 2. Return completion.
return completion;
}
}

11
Userland/Libraries/LibJS/Runtime/AbstractOperations.h
View File

@ -42,6 +42,17 @@ ThrowCompletionOr<Object*> get_prototype_from_constructor(VM&, FunctionObject co
Object* create_unmapped_arguments_object(VM&, Span<Value> arguments);
Object* create_mapped_arguments_object(VM&, FunctionObject&, Vector<FunctionParameter> const&, Span<Value> arguments, Environment&);
struct DisposableResource {
Value resource_value;
NonnullGCPtr<FunctionObject> dispose_method;
};
ThrowCompletionOr<void> add_disposable_resource(VM&, Vector<DisposableResource>& disposable, Value, Environment::InitializeBindingHint, FunctionObject* = nullptr);
ThrowCompletionOr<DisposableResource> create_disposable_resource(VM&, Value, Environment::InitializeBindingHint, FunctionObject* method = nullptr);
ThrowCompletionOr<GCPtr<FunctionObject>> get_dispose_method(VM&, Value, Environment::InitializeBindingHint);
Completion dispose(VM& vm, Value, NonnullGCPtr<FunctionObject> method);
Completion dispose_resources(VM& vm, Vector<DisposableResource> const& disposable, Completion completion);
Completion dispose_resources(VM& vm, GCPtr<DeclarativeEnvironment> disposable, Completion completion);
enum class CanonicalIndexMode {
DetectNumericRoundtrip,
IgnoreNumericRoundtrip,

12
Userland/Libraries/LibJS/Runtime/DeclarativeEnvironment.cpp
View File

@ -5,6 +5,7 @@
*/
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/DeclarativeEnvironment.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FunctionObject.h>
@ -42,6 +43,11 @@ void DeclarativeEnvironment::visit_edges(Visitor& visitor)
Base::visit_edges(visitor);
for (auto& binding : m_bindings)
visitor.visit(binding.value);
for (auto& disposable : m_disposable_resource_stack) {
visitor.visit(disposable.resource_value);
visitor.visit(disposable.dispose_method);
}
}
// 9.1.1.1.1 HasBinding ( N ), https://tc39.es/ecma262/#sec-declarative-environment-records-hasbinding-n
@ -97,7 +103,7 @@ ThrowCompletionOr<void> DeclarativeEnvironment::create_immutable_binding(VM&, De
// 9.1.1.1.4 InitializeBinding ( N, V ), https://tc39.es/ecma262/#sec-declarative-environment-records-initializebinding-n-v
// 4.1.1.1.1 InitializeBinding ( N, V, hint ), https://tc39.es/proposal-explicit-resource-management/#sec-declarative-environment-records
ThrowCompletionOr<void> DeclarativeEnvironment::initialize_binding(VM&, DeprecatedFlyString const& name, Value value, Environment::InitializeBindingHint)
ThrowCompletionOr<void> DeclarativeEnvironment::initialize_binding(VM& vm, DeprecatedFlyString const& name, Value value, Environment::InitializeBindingHint hint)
{
auto binding_and_index = find_binding_and_index(name);
VERIFY(binding_and_index.has_value());
@ -106,7 +112,9 @@ ThrowCompletionOr<void> DeclarativeEnvironment::initialize_binding(VM&, Deprecat
// 1. Assert: envRec must have an uninitialized binding for N.
VERIFY(binding.initialized == false);
// FIXME: 2. If hint is not normal, perform ? AddDisposableResource(envRec, V, hint).
// 2. If hint is not normal, perform ? AddDisposableResource(envRec, V, hint).
if (hint != Environment::InitializeBindingHint::Normal)
TRY(add_disposable_resource(vm, m_disposable_resource_stack, value, hint));
// 3. Set the bound value for N in envRec to V.
binding.value = value;

5
Userland/Libraries/LibJS/Runtime/DeclarativeEnvironment.h
View File

@ -8,6 +8,7 @@
#include <AK/DeprecatedFlyString.h>
#include <AK/HashMap.h>
#include <LibJS/Runtime/AbstractOperations.h>
#include <LibJS/Runtime/Completion.h>
#include <LibJS/Runtime/Environment.h>
#include <LibJS/Runtime/Value.h>
@ -63,6 +64,9 @@ private:
ThrowCompletionOr<Value> get_binding_value_direct(VM&, Binding&, bool strict);
ThrowCompletionOr<void> set_mutable_binding_direct(VM&, Binding&, Value, bool strict);
friend Completion dispose_resources(VM&, GCPtr<DeclarativeEnvironment>, Completion);
Vector<DisposableResource> const& disposable_resource_stack() const { return m_disposable_resource_stack; }
protected:
DeclarativeEnvironment();
explicit DeclarativeEnvironment(Environment* parent_environment);
@ -116,6 +120,7 @@ private:
virtual bool is_declarative_environment() const override { return true; }
Vector<Binding> m_bindings;
Vector<DisposableResource> m_disposable_resource_stack;
};
template<>

28
Userland/Libraries/LibJS/Runtime/ECMAScriptFunctionObject.cpp
View File

@ -736,7 +736,7 @@ void async_block_start(VM& vm, NonnullRefPtr<Statement> const& async_body, Promi
auto& running_context = vm.running_execution_context();
// 3. Set the code evaluation state of asyncContext such that when evaluation is resumed for that execution context the following steps will be performed:
auto execution_steps = NativeFunction::create(realm, "", [&async_body, &promise_capability](auto& vm) -> ThrowCompletionOr<Value> {
auto execution_steps = NativeFunction::create(realm, "", [&async_body, &promise_capability, &async_context](auto& vm) -> ThrowCompletionOr<Value> {
// a. Let result be the result of evaluating asyncBody.
auto result = async_body->execute(vm.interpreter());
@ -745,17 +745,24 @@ void async_block_start(VM& vm, NonnullRefPtr<Statement> const& async_body, Promi
// c. Remove asyncContext from the execution context stack and restore the execution context that is at the top of the execution context stack as the running execution context.
vm.pop_execution_context();
// d. If result.[[Type]] is normal, then
// d. Let env be asyncContext's LexicalEnvironment.
auto* env = async_context.lexical_environment;
VERIFY(is<DeclarativeEnvironment>(env));
// e. Set result to DisposeResources(env, result).
result = dispose_resources(vm, static_cast<DeclarativeEnvironment*>(env), result);
// f. If result.[[Type]] is normal, then
if (result.type() == Completion::Type::Normal) {
// i. Perform ! Call(promiseCapability.[[Resolve]], undefined, « undefined »).
MUST(call(vm, *promise_capability.resolve(), js_undefined(), js_undefined()));
}
// e. Else if result.[[Type]] is return, then
// g. Else if result.[[Type]] is return, then
else if (result.type() == Completion::Type::Return) {
// i. Perform ! Call(promiseCapability.[[Resolve]], undefined, « result.[[Value]] »).
MUST(call(vm, *promise_capability.resolve(), js_undefined(), *result.value()));
}
// f. Else,
// h. Else,
else {
// i. Assert: result.[[Type]] is throw.
VERIFY(result.type() == Completion::Type::Throw);
@ -763,7 +770,7 @@ void async_block_start(VM& vm, NonnullRefPtr<Statement> const& async_body, Promi
// ii. Perform ! Call(promiseCapability.[[Reject]], undefined, « result.[[Value]] »).
MUST(call(vm, *promise_capability.reject(), js_undefined(), *result.value()));
}
// g. Return unused.
// i. Return unused.
// NOTE: We don't support returning an empty/optional/unused value here.
return js_undefined();
});
@ -882,8 +889,15 @@ Completion ECMAScriptFunctionObject::ordinary_call_evaluate_body()
// 1. Perform ? FunctionDeclarationInstantiation(functionObject, argumentsList).
TRY(function_declaration_instantiation(ast_interpreter));
// 2. Return the result of evaluating FunctionStatementList.
return m_ecmascript_code->execute(*ast_interpreter);
// 2. Let result be result of evaluating FunctionStatementList.
auto result = m_ecmascript_code->execute(*ast_interpreter);
// 3. Let env be the running execution context's LexicalEnvironment.
auto* env = vm.running_execution_context().lexical_environment;
VERIFY(is<DeclarativeEnvironment>(env));
// 4. Return ? DisposeResources(env, result).
return dispose_resources(vm, static_cast<DeclarativeEnvironment*>(env), result);
}
// AsyncFunctionBody : FunctionBody
else if (m_kind == FunctionKind::Async) {

1
Userland/Libraries/LibJS/Runtime/ErrorTypes.h
View File

@ -85,6 +85,7 @@
M(ModuleNotFound, "Cannot find/open module: '{}'") \
M(ModuleNotFoundNoReferencingScript, "Cannot resolve module {} without any active script or module") \
M(NegativeExponent, "Exponent must be positive") \
M(NoDisposeMethod, "{} does not have dispose method") \
M(NonExtensibleDefine, "Cannot define property {} on non-extensible object") \
M(NotAConstructor, "{} is not a constructor") \
M(NotAFunction, "{} is not a function") \

13
Userland/Libraries/LibJS/SourceTextModule.cpp
View File

@ -687,13 +687,20 @@ ThrowCompletionOr<void> SourceTextModule::execute_module(VM& vm, GCPtr<PromiseCa
// c. Let result be the result of evaluating module.[[ECMAScriptCode]].
auto result = m_ecmascript_code->execute(vm.interpreter());
// d. Suspend moduleContext and remove it from the execution context stack.
// d. Let env be moduleContext's LexicalEnvironment.
auto* env = module_context.lexical_environment;
VERIFY(is<DeclarativeEnvironment>(*env));
// e. Set result to DisposeResources(env, result).
result = dispose_resources(vm, static_cast<DeclarativeEnvironment*>(env), result);
// f. Suspend moduleContext and remove it from the execution context stack.
vm.pop_execution_context();
// e. Resume the context that is now on the top of the execution context stack as the running execution context.
// g. Resume the context that is now on the top of the execution context stack as the running execution context.
// FIXME: We don't have resume yet.
// f. If result is an abrupt completion, then
// h. If result is an abrupt completion, then
if (result.is_error()) {
// i. Return ? result.
return result;

4
Userland/Libraries/LibJS/Tests/modules/basic-modules.js
View File

@ -206,6 +206,10 @@ describe("in- and exports", () => {
test("exporting anonymous function", () => {
expectModulePassed("./anon-func-decl-default-export.mjs");
});
test("can have top level using declarations which trigger at the end of running a module", () => {
expectModulePassed("./top-level-dispose.mjs");
});
});
describe("loops", () => {

14
Userland/Libraries/LibJS/Tests/modules/top-level-dispose.mjs Normal file
View File

@ -0,0 +1,14 @@
export let passed = false;
let failed = false;
if (passed)
failed = true;
using a = { [Symbol.dispose]() { if (!failed) passed = true; } }
if (passed)
failed = true;
failed = true;
// Should trigger before
using b = { [Symbol.dispose]() { if (!passed) failed = false; } }

386
Userland/Libraries/LibJS/Tests/using-declaration.js Normal file
View File

@ -0,0 +1,386 @@
describe("basic usage", () => {
test("disposes after block exit", () => {
let disposed = false;
let inBlock = false;
{
expect(disposed).toBeFalse();
using a = { [Symbol.dispose]() { disposed = true; } };
inBlock = true;
expect(disposed).toBeFalse();
}
expect(inBlock).toBeTrue();
expect(disposed).toBeTrue();
});
test("disposes in reverse order after block exit", () => {
const disposed = [];
{
expect(disposed).toHaveLength(0);
using a = { [Symbol.dispose]() { disposed.push('a'); } };
using b = { [Symbol.dispose]() { disposed.push('b'); } };
expect(disposed).toHaveLength(0);
}
expect(disposed).toEqual(['b', 'a']);
});
test("disposes in reverse order after block exit even in same declaration", () => {
const disposed = [];
{
expect(disposed).toHaveLength(0);
using a = { [Symbol.dispose]() { disposed.push('a'); } },
b = { [Symbol.dispose]() { disposed.push('b'); } };
expect(disposed).toHaveLength(0);
}
expect(disposed).toEqual(['b', 'a']);
});
});
describe("behavior with exceptions", () => {
function ExpectedError(name) { this.name = name; }
test("is run even after throw", () => {
let disposed = false;
let inBlock = false;
let inCatch = false;
try {
expect(disposed).toBeFalse();
using a = { [Symbol.dispose]() { disposed = true; } };
inBlock = true;
expect(disposed).toBeFalse();
throw new ExpectedError();
expect().fail();
} catch (e) {
expect(disposed).toBeTrue();
expect(e).toBeInstanceOf(ExpectedError);
inCatch = true;
}
expect(disposed).toBeTrue();
expect(inBlock).toBeTrue();
expect(inCatch).toBeTrue();
});
test("throws error if dispose method does", () => {
let disposed = false;
let endOfTry = false;
let inCatch = false;
try {
expect(disposed).toBeFalse();
using a = { [Symbol.dispose]() {
disposed = true;
throw new ExpectedError();
} };
expect(disposed).toBeFalse();
endOfTry = true;
} catch (e) {
expect(disposed).toBeTrue();
expect(e).toBeInstanceOf(ExpectedError);
inCatch = true;
}
expect(disposed).toBeTrue();
expect(endOfTry).toBeTrue();
expect(inCatch).toBeTrue();
});
test("if block and using throw get suppressed error", () => {
let disposed = false;
let inCatch = false;
try {
expect(disposed).toBeFalse();
using a = { [Symbol.dispose]() {
disposed = true;
throw new ExpectedError('dispose');
} };
expect(disposed).toBeFalse();
throw new ExpectedError('throw');
} catch (e) {
expect(disposed).toBeTrue();
expect(e).toBeInstanceOf(SuppressedError);
expect(e.error).toBeInstanceOf(ExpectedError);
expect(e.error.name).toBe('dispose');
expect(e.suppressed).toBeInstanceOf(ExpectedError);
expect(e.suppressed.name).toBe('throw');
inCatch = true;
}
expect(disposed).toBeTrue();
expect(inCatch).toBeTrue();
});
test("multiple throwing disposes give suppressed error", () => {
let inCatch = false;
try {
{
using a = { [Symbol.dispose]() {
throw new ExpectedError('a');
} };
using b = { [Symbol.dispose]() {
throw new ExpectedError('b');
} };
}
expect().fail();
} catch (e) {
expect(e).toBeInstanceOf(SuppressedError);
expect(e.error).toBeInstanceOf(ExpectedError);
expect(e.error.name).toBe('a');
expect(e.suppressed).toBeInstanceOf(ExpectedError);
expect(e.suppressed.name).toBe('b');
inCatch = true;
}
expect(inCatch).toBeTrue();
});
test("3 throwing disposes give chaining suppressed error", () => {
let inCatch = false;
try {
{
using a = { [Symbol.dispose]() {
throw new ExpectedError('a');
} };
using b = { [Symbol.dispose]() {
throw new ExpectedError('b');
} };
using c = { [Symbol.dispose]() {
throw new ExpectedError('c');
} };
}
expect().fail();
} catch (e) {
expect(e).toBeInstanceOf(SuppressedError);
expect(e.error).toBeInstanceOf(ExpectedError);
expect(e.error.name).toBe('a');
expect(e.suppressed).toBeInstanceOf(SuppressedError);
const inner = e.suppressed;
expect(inner.error).toBeInstanceOf(ExpectedError);
expect(inner.error.name).toBe('b');
expect(inner.suppressed).toBeInstanceOf(ExpectedError);
expect(inner.suppressed.name).toBe('c');
inCatch = true;
}
expect(inCatch).toBeTrue();
});
test("normal error and multiple disposing erorrs give chaining suppressed errors", () => {
let inCatch = false;
try {
using a = { [Symbol.dispose]() {
throw new ExpectedError('a');
} };
using b = { [Symbol.dispose]() {
throw new ExpectedError('b');
} };
throw new ExpectedError('top');
} catch (e) {
expect(e).toBeInstanceOf(SuppressedError);
expect(e.error).toBeInstanceOf(ExpectedError);
expect(e.error.name).toBe('a');
expect(e.suppressed).toBeInstanceOf(SuppressedError);
const inner = e.suppressed;
expect(inner.error).toBeInstanceOf(ExpectedError);
expect(inner.error.name).toBe('b');
expect(inner.suppressed).toBeInstanceOf(ExpectedError);
expect(inner.suppressed.name).toBe('top');
inCatch = true;
}
expect(inCatch).toBeTrue();
});
});
describe("works in a bunch of scopes", () => {
test("works in block", () => {
let dispose = false;
expect(dispose).toBeFalse();
{
expect(dispose).toBeFalse();
using a = { [Symbol.dispose]() { dispose = true; } }
expect(dispose).toBeFalse();
}
expect(dispose).toBeTrue();
});
test("works in static class block", () => {
let dispose = false;
expect(dispose).toBeFalse();
class A {
static {
expect(dispose).toBeFalse();
using a = { [Symbol.dispose]() { dispose = true; } }
expect(dispose).toBeFalse();
}
}
expect(dispose).toBeTrue();
});
test("works in function", () => {
let dispose = [];
function f(val) {
const disposeLength = dispose.length;
using a = { [Symbol.dispose]() { dispose.push(val); } }
expect(dispose.length).toBe(disposeLength);
}
expect(dispose).toEqual([]);
f(0);
expect(dispose).toEqual([0]);
f(1);
expect(dispose).toEqual([0, 1]);
});
test("switch block is treated as full block in function", () => {
let disposeFull = [];
let disposeInner = false;
function pusher(val) {
return {
val,
[Symbol.dispose]() { disposeFull.push(val); }
};
}
switch (2) {
case 3:
using notDisposed = { [Symbol.dispose]() { expect().fail("not-disposed 1"); } };
case 2:
expect(disposeFull).toEqual([]);
using a = pusher('a');
expect(disposeFull).toEqual([]);
using b = pusher('b');
expect(disposeFull).toEqual([]);
expect(b.val).toBe('b');
expect(disposeInner).toBeFalse();
// fallthrough
case 1: {
expect(disposeFull).toEqual([]);
expect(disposeInner).toBeFalse();
using inner = { [Symbol.dispose]() { disposeInner = true; } }
expect(disposeInner).toBeFalse();
}
expect(disposeInner).toBeTrue();
using c = pusher('c');
expect(c.val).toBe('c');
break;
case 0:
using notDisposed2 = { [Symbol.dispose]() { expect().fail("not-disposed 2"); } };
}
expect(disposeInner).toBeTrue();
expect(disposeFull).toEqual(['c', 'b', 'a']);
});
});
describe("invalid using bindings", () => {
test("nullish values do not throw", () => {
using a = null, b = undefined;
expect(a).toBeNull();
expect(b).toBeUndefined();
});
test("non-object throws", () => {
[0, "a", true, NaN, 4n, Symbol.dispose].forEach(value => {
expect(() => {
using v = value;
}).toThrowWithMessage(TypeError, "is not an object");
});
});
test("object without dispose throws", () => {
expect(() => {
using a = {};
}).toThrowWithMessage(TypeError, "does not have dispose method");
});
test("object with non callable dispose throws", () => {
[0, "a", true, NaN, 4n, Symbol.dispose, [], {}].forEach(value => {
expect(() => {
using a = { [Symbol.dispose]: value };
}).toThrowWithMessage(TypeError, "is not a function");
});
});
});
describe("using is still a valid variable name", () => {
test("var", () => {
"use strict";
var using = 1;
expect(using).toBe(1);
});
test("const", () => {
"use strict";
const using = 1;
expect(using).toBe(1);
});
test("let", () => {
"use strict";
let using = 1;
expect(using).toBe(1);
});
test("using", () => {
"use strict";
using using = null;
expect(using).toBeNull();
});
test("function", () => {
"use strict";
function using() { return 1; }
expect(using()).toBe(1);
});
});
describe("syntax errors / werid artifacts which remain valid", () => {
test("no patterns in using", () => {
expect("using {a} = {}").not.toEval();
expect("using a, {a} = {}").not.toEval();
expect("using a = null, [b] = [null]").not.toEval();
});
test("using with array pattern is valid array access", () => {
const using = [0, 9999];
const a = 1;
expect(eval("using [a] = 1")).toBe(1);
expect(using[1]).toBe(1);
expect(eval("using [{a: a}, a] = 2")).toBe(2);
expect(using[1]).toBe(2);
expect(eval("using [a, a] = 3")).toBe(3);
expect(using[1]).toBe(3);
expect(eval("using [[a, a], a] = 4")).toBe(4);
expect(using[1]).toBe(4);
expect(eval("using [2, 1, a] = 5")).toBe(5);
expect(using[1]).toBe(5);
});
test("declaration without initializer", () => {
expect("using a").not.toEval();
});
test("no repeat declarations in single using", () => {
expect("using a = null, a = null;").not.toEval();
});
test("cannot have a using declaration named let", () => {
expect("using let = null").not.toEval();
});
});