ladybird/Libraries/LibJS/Runtime/LexicalEnvironment.h
Jack Karamanian 7533fd8b02 LibJS: Initial class implementation; allow super expressions in object
literal methods; add EnvrionmentRecord fields and methods to
LexicalEnvironment

Adding EnvrionmentRecord's fields and methods lets us throw an exception
when |this| is not initialized, which occurs when the super constructor
in a derived class has not yet been called, or when |this| has already
been initialized (the super constructor was already called).
2020-06-29 17:54:54 +02:00

105 lines
3.7 KiB
C++

/*
* Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice, this
* list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#include <AK/FlyString.h>
#include <AK/HashMap.h>
#include <LibJS/Runtime/Cell.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
struct Variable {
Value value;
DeclarationKind declaration_kind;
};
class LexicalEnvironment final : public Cell {
public:
enum class ThisBindingStatus {
Lexical,
Initialized,
Uninitialized,
};
enum class EnvironmentRecordType {
Declarative,
Function,
Global,
Object,
Module,
};
LexicalEnvironment();
LexicalEnvironment(EnvironmentRecordType);
LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent);
LexicalEnvironment(HashMap<FlyString, Variable> variables, LexicalEnvironment* parent, EnvironmentRecordType);
virtual ~LexicalEnvironment() override;
LexicalEnvironment* parent() const { return m_parent; }
Optional<Variable> get(const FlyString&) const;
void set(const FlyString&, Variable);
void clear();
const HashMap<FlyString, Variable>& variables() const { return m_variables; }
void set_home_object(Value object) { m_home_object = object; }
bool has_super_binding() const;
Value get_super_base();
bool has_this_binding() const;
ThisBindingStatus this_binding_status() const { return m_this_binding_status; }
Value get_this_binding() const;
void bind_this_value(Value this_value);
// Not a standard operation.
void replace_this_binding(Value this_value) { m_this_value = this_value; }
Value new_target() const { return m_new_target; };
void set_new_target(Value new_target) { m_new_target = new_target; }
Function* current_function() const { return m_current_function; }
void set_current_function(Function& function) { m_current_function = &function; }
private:
virtual const char* class_name() const override { return "LexicalEnvironment"; }
virtual void visit_children(Visitor&) override;
LexicalEnvironment* m_parent { nullptr };
HashMap<FlyString, Variable> m_variables;
EnvironmentRecordType m_environment_record_type = EnvironmentRecordType::Declarative;
ThisBindingStatus m_this_binding_status = ThisBindingStatus::Uninitialized;
Value m_home_object;
Value m_this_value;
Value m_new_target;
// Corresponds to [[FunctionObject]]
Function* m_current_function { nullptr };
};
}