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https://github.com/LadybirdBrowser/ladybird.git
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9ea6ef4ed1
The motivation for this change is twofold: - Returning a JS::Value is misleading as one would expect it to carry some meaningful information, like maybe the error object that's being created, but in fact it is always empty. Supposedly to serve as a shortcut for the common case of "throw and return empty value", but that's just leading us to my second point. - Inconsistent usage / coding style: as of this commit there are 114 uses of throw_exception() discarding its return value and 55 uses directly returning the call result (in LibJS, not counting LibWeb); with the first style often having a more explicit empty value (or nullptr in some cases) return anyway. One more line to always make the return value obvious is should be worth it. So now it's basically always these steps, which is already being used in the majority of cases (as outlined above): - Throw an exception. This mutates interpreter state by updating m_exception and unwinding, but doesn't return anything. - Let the caller explicitly return an empty value, nullptr or anything else itself.
133 lines
4.3 KiB
C++
133 lines
4.3 KiB
C++
/*
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* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <LibJS/Interpreter.h>
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#include <LibJS/Runtime/Error.h>
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#include <LibJS/Runtime/Function.h>
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#include <LibJS/Runtime/LexicalEnvironment.h>
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#include <LibJS/Runtime/Value.h>
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namespace JS {
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LexicalEnvironment::LexicalEnvironment()
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{
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}
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LexicalEnvironment::LexicalEnvironment(EnvironmentRecordType environment_record_type)
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: m_environment_record_type(environment_record_type)
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{
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}
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LexicalEnvironment::LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent)
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: m_parent(parent)
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, m_variables(move(variables))
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{
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}
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LexicalEnvironment::LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent, EnvironmentRecordType environment_record_type)
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: m_parent(parent)
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, m_variables(move(variables))
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, m_environment_record_type(environment_record_type)
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{
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}
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LexicalEnvironment::~LexicalEnvironment()
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{
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}
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void LexicalEnvironment::visit_children(Visitor& visitor)
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{
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Cell::visit_children(visitor);
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visitor.visit(m_parent);
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visitor.visit(m_this_value);
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visitor.visit(m_home_object);
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visitor.visit(m_new_target);
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visitor.visit(m_current_function);
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for (auto& it : m_variables)
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visitor.visit(it.value.value);
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}
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Optional<Variable> LexicalEnvironment::get(const FlyString& name) const
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{
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return m_variables.get(name);
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}
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void LexicalEnvironment::set(const FlyString& name, Variable variable)
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{
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m_variables.set(name, variable);
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}
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bool LexicalEnvironment::has_super_binding() const
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{
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return m_environment_record_type == EnvironmentRecordType::Function && this_binding_status() != ThisBindingStatus::Lexical && m_home_object.is_object();
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}
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Value LexicalEnvironment::get_super_base()
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{
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ASSERT(has_super_binding());
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if (m_home_object.is_object())
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return m_home_object.as_object().prototype();
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return {};
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}
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bool LexicalEnvironment::has_this_binding() const
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{
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// More like "is_capable_of_having_a_this_binding".
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switch (m_environment_record_type) {
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case EnvironmentRecordType::Declarative:
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case EnvironmentRecordType::Object:
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return false;
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case EnvironmentRecordType::Function:
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return this_binding_status() != ThisBindingStatus::Lexical;
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case EnvironmentRecordType::Module:
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case EnvironmentRecordType::Global:
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return true;
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}
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ASSERT_NOT_REACHED();
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}
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Value LexicalEnvironment::get_this_binding() const
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{
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ASSERT(has_this_binding());
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if (this_binding_status() == ThisBindingStatus::Uninitialized) {
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interpreter().throw_exception<ReferenceError>(ErrorType::ThisHasNotBeenInitialized);
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return {};
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}
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return m_this_value;
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}
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void LexicalEnvironment::bind_this_value(Value this_value)
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{
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ASSERT(has_this_binding());
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if (m_this_binding_status == ThisBindingStatus::Initialized) {
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interpreter().throw_exception<ReferenceError>(ErrorType::ThisIsAlreadyInitialized);
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return;
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}
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m_this_value = this_value;
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m_this_binding_status = ThisBindingStatus::Initialized;
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}
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}
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