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- /*
- * Copyright (c) 2020-2021, Andreas Kling <kling@serenityos.org>
- *
- * SPDX-License-Identifier: BSD-2-Clause
- */
- #include <LibJS/Interpreter.h>
- #include <LibJS/Runtime/DeclarativeEnvironment.h>
- #include <LibJS/Runtime/Error.h>
- #include <LibJS/Runtime/FunctionObject.h>
- #include <LibJS/Runtime/GlobalObject.h>
- #include <LibJS/Runtime/Value.h>
- namespace JS {
- DeclarativeEnvironment::DeclarativeEnvironment()
- : Environment(nullptr)
- {
- }
- DeclarativeEnvironment::DeclarativeEnvironment(Environment* parent_scope)
- : Environment(parent_scope)
- {
- }
- DeclarativeEnvironment::~DeclarativeEnvironment()
- {
- }
- void DeclarativeEnvironment::visit_edges(Visitor& visitor)
- {
- Base::visit_edges(visitor);
- for (auto& binding : m_bindings)
- visitor.visit(binding.value);
- }
- // 9.1.1.1.1 HasBinding ( N ), https://tc39.es/ecma262/#sec-declarative-environment-records-hasbinding-n
- ThrowCompletionOr<bool> DeclarativeEnvironment::has_binding(FlyString const& name, Optional<size_t>* out_index) const
- {
- auto it = m_names.find(name);
- if (it == m_names.end())
- return false;
- if (!is_permanently_screwed_by_eval() && out_index)
- *out_index = it->value;
- return true;
- }
- // 9.1.1.1.2 CreateMutableBinding ( N, D ), https://tc39.es/ecma262/#sec-declarative-environment-records-createmutablebinding-n-d
- ThrowCompletionOr<void> DeclarativeEnvironment::create_mutable_binding(GlobalObject&, FlyString const& name, bool can_be_deleted)
- {
- // 2. Create a mutable binding in envRec for N and record that it is uninitialized. If D is true, record that the newly created binding may be deleted by a subsequent DeleteBinding call.
- m_bindings.append(Binding {
- .value = {},
- .strict = false,
- .mutable_ = true,
- .can_be_deleted = can_be_deleted,
- .initialized = false,
- });
- auto result = m_names.set(name, m_bindings.size() - 1);
- // 1. Assert: envRec does not already have a binding for N.
- VERIFY(result == AK::HashSetResult::InsertedNewEntry);
- // 3. Return NormalCompletion(empty).
- return {};
- }
- // 9.1.1.1.3 CreateImmutableBinding ( N, S ), https://tc39.es/ecma262/#sec-declarative-environment-records-createimmutablebinding-n-s
- ThrowCompletionOr<void> DeclarativeEnvironment::create_immutable_binding(GlobalObject&, FlyString const& name, bool strict)
- {
- // 2. Create an immutable binding in envRec for N and record that it is uninitialized. If S is true, record that the newly created binding is a strict binding.
- m_bindings.append(Binding {
- .value = {},
- .strict = strict,
- .mutable_ = false,
- .can_be_deleted = false,
- .initialized = false,
- });
- auto result = m_names.set(name, m_bindings.size() - 1);
- // 1. Assert: envRec does not already have a binding for N.
- VERIFY(result == AK::HashSetResult::InsertedNewEntry);
- // 3. Return NormalCompletion(empty).
- return {};
- }
- // 9.1.1.1.4 InitializeBinding ( N, V ), https://tc39.es/ecma262/#sec-declarative-environment-records-initializebinding-n-v
- ThrowCompletionOr<void> DeclarativeEnvironment::initialize_binding(GlobalObject&, FlyString const& name, Value value)
- {
- auto it = m_names.find(name);
- VERIFY(it != m_names.end());
- auto& binding = m_bindings[it->value];
- // 1. Assert: envRec must have an uninitialized binding for N.
- VERIFY(binding.initialized == false);
- // 2. Set the bound value for N in envRec to V.
- binding.value = value;
- // 3. Record that the binding for N in envRec has been initialized.
- binding.initialized = true;
- // 4. Return NormalCompletion(empty).
- return {};
- }
- // 9.1.1.1.5 SetMutableBinding ( N, V, S ), https://tc39.es/ecma262/#sec-declarative-environment-records-setmutablebinding-n-v-s
- ThrowCompletionOr<void> DeclarativeEnvironment::set_mutable_binding(GlobalObject& global_object, FlyString const& name, Value value, bool strict)
- {
- // 1. If envRec does not have a binding for N, then
- auto it = m_names.find(name);
- if (it == m_names.end()) {
- // a. If S is true, throw a ReferenceError exception.
- if (strict)
- return vm().throw_completion<ReferenceError>(global_object, ErrorType::UnknownIdentifier, name);
- // b. Perform envRec.CreateMutableBinding(N, true).
- MUST(create_mutable_binding(global_object, name, true));
- // c. Perform envRec.InitializeBinding(N, V).
- MUST(initialize_binding(global_object, name, value));
- // d. Return NormalCompletion(empty).
- return {};
- }
- // 2-5. (extracted into a non-standard function below)
- TRY(set_mutable_binding_direct(global_object, it->value, value, strict));
- // 6. Return NormalCompletion(empty).
- return {};
- }
- ThrowCompletionOr<void> DeclarativeEnvironment::set_mutable_binding_direct(GlobalObject& global_object, size_t index, Value value, bool strict)
- {
- auto& binding = m_bindings[index];
- if (binding.strict)
- strict = true;
- if (!binding.initialized)
- return vm().throw_completion<ReferenceError>(global_object, ErrorType::BindingNotInitialized, name_from_index(index));
- if (binding.mutable_) {
- binding.value = value;
- } else {
- if (strict)
- return vm().throw_completion<TypeError>(global_object, ErrorType::InvalidAssignToConst);
- }
- return {};
- }
- // 9.1.1.1.6 GetBindingValue ( N, S ), https://tc39.es/ecma262/#sec-declarative-environment-records-getbindingvalue-n-s
- ThrowCompletionOr<Value> DeclarativeEnvironment::get_binding_value(GlobalObject& global_object, FlyString const& name, bool strict)
- {
- // 1. Assert: envRec has a binding for N.
- auto it = m_names.find(name);
- VERIFY(it != m_names.end());
- // 2-3. (extracted into a non-standard function below)
- return get_binding_value_direct(global_object, it->value, strict);
- }
- ThrowCompletionOr<Value> DeclarativeEnvironment::get_binding_value_direct(GlobalObject& global_object, size_t index, bool)
- {
- auto& binding = m_bindings[index];
- // 2. If the binding for N in envRec is an uninitialized binding, throw a ReferenceError exception.
- if (!binding.initialized)
- return vm().throw_completion<ReferenceError>(global_object, ErrorType::BindingNotInitialized, name_from_index(index));
- // 3. Return the value currently bound to N in envRec.
- return binding.value;
- }
- // 9.1.1.1.7 DeleteBinding ( N ), https://tc39.es/ecma262/#sec-declarative-environment-records-deletebinding-n
- ThrowCompletionOr<bool> DeclarativeEnvironment::delete_binding(GlobalObject&, FlyString const& name)
- {
- // 1. Assert: envRec has a binding for the name that is the value of N.
- auto it = m_names.find(name);
- VERIFY(it != m_names.end());
- auto& binding = m_bindings[it->value];
- // 2. If the binding for N in envRec cannot be deleted, return false.
- if (!binding.can_be_deleted)
- return false;
- // 3. Remove the binding for N from envRec.
- // NOTE: We keep the entry in m_bindings to avoid disturbing indices.
- binding = {};
- m_names.remove(it);
- // 4. Return true.
- return true;
- }
- void DeclarativeEnvironment::initialize_or_set_mutable_binding(Badge<ScopeNode>, GlobalObject& global_object, FlyString const& name, Value value)
- {
- auto it = m_names.find(name);
- VERIFY(it != m_names.end());
- auto& binding = m_bindings[it->value];
- if (!binding.initialized)
- MUST(initialize_binding(global_object, name, value));
- else
- MUST(set_mutable_binding(global_object, name, value, false));
- }
- Vector<String> DeclarativeEnvironment::bindings() const
- {
- Vector<String> names;
- for (auto& it : m_names) {
- names.append(it.key);
- }
- return names;
- }
- FlyString const& DeclarativeEnvironment::name_from_index(size_t index) const
- {
- for (auto& it : m_names) {
- if (it.value == index)
- return it.key;
- }
- VERIFY_NOT_REACHED();
- }
- }
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