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/*
* 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.
*/
#include <AK/Badge.h>
#include <LibJS/AST.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/ArrayPrototype.h>
#include <LibJS/Runtime/BooleanPrototype.h>
#include <LibJS/Runtime/DatePrototype.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/ErrorPrototype.h>
#include <LibJS/Runtime/FunctionPrototype.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/NativeFunction.h>
#include <LibJS/Runtime/NumberPrototype.h>
#include <LibJS/Runtime/Object.h>
#include <LibJS/Runtime/ObjectPrototype.h>
#include <LibJS/Runtime/Shape.h>
#include <LibJS/Runtime/StringPrototype.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
Interpreter::Interpreter()
: m_heap(*this)
{
m_empty_object_shape = heap().allocate<Shape>();
// These are done first since other prototypes depend on their presence.
m_object_prototype = heap().allocate<ObjectPrototype>();
m_function_prototype = heap().allocate<FunctionPrototype>();
#define __JS_ENUMERATE(ClassName, snake_name, PrototypeName, ConstructorName) \
if (!m_##snake_name##_prototype) \
m_##snake_name##_prototype = heap().allocate<PrototypeName>();
JS_ENUMERATE_BUILTIN_TYPES
#undef __JS_ENUMERATE
}
Interpreter::~Interpreter()
{
}
Value Interpreter::run(const Statement& statement, ArgumentVector arguments, ScopeType scope_type)
{
if (!statement.is_scope_node())
return statement.execute(*this);
auto& block = static_cast<const ScopeNode&>(statement);
enter_scope(block, move(arguments), scope_type);
m_last_value = js_undefined();
for (auto& node : block.children()) {
m_last_value = node.execute(*this);
if (m_unwind_until != ScopeType::None)
break;
}
bool did_return = m_unwind_until == ScopeType::Function;
if (m_unwind_until == scope_type)
m_unwind_until = ScopeType::None;
exit_scope(block);
return did_return ? m_last_value : js_undefined();
}
void Interpreter::enter_scope(const ScopeNode& scope_node, ArgumentVector arguments, ScopeType scope_type)
{
HashMap<FlyString, Variable> scope_variables_with_declaration_kind;
scope_variables_with_declaration_kind.ensure_capacity(16);
for (auto& declaration : scope_node.variables()) {
for (auto& declarator : declaration.declarations()) {
if (scope_node.is_program())
global_object().put(declarator.id().string(), js_undefined());
else
scope_variables_with_declaration_kind.set(declarator.id().string(), { js_undefined(), declaration.declaration_kind() });
}
}
for (auto& argument : arguments) {
scope_variables_with_declaration_kind.set(argument.name, { argument.value, DeclarationKind::Var });
}
m_scope_stack.append({ scope_type, scope_node, move(scope_variables_with_declaration_kind) });
}
void Interpreter::exit_scope(const ScopeNode& scope_node)
{
while (!m_scope_stack.is_empty()) {
auto popped_scope = m_scope_stack.take_last();
if (popped_scope.scope_node.ptr() == &scope_node)
break;
}
// If we unwind all the way, just reset m_unwind_until so that future "return" doesn't break.
if (m_scope_stack.is_empty())
m_unwind_until = ScopeType::None;
}
void Interpreter::set_variable(const FlyString& name, Value value, bool first_assignment)
{
for (ssize_t i = m_scope_stack.size() - 1; i >= 0; --i) {
auto& scope = m_scope_stack.at(i);
auto possible_match = scope.variables.get(name);
if (possible_match.has_value()) {
if (!first_assignment && possible_match.value().declaration_kind == DeclarationKind::Const) {
throw_exception<TypeError>("Assignment to constant variable");
return;
}
scope.variables.set(move(name), { move(value), possible_match.value().declaration_kind });
return;
}
}
global_object().put(move(name), move(value));
}
Optional<Value> Interpreter::get_variable(const FlyString& name)
{
for (ssize_t i = m_scope_stack.size() - 1; i >= 0; --i) {
auto& scope = m_scope_stack.at(i);
auto value = scope.variables.get(name);
if (value.has_value())
return value.value().value;
}
return global_object().get(name);
}
void Interpreter::gather_roots(Badge<Heap>, HashTable<Cell*>& roots)
{
roots.set(m_empty_object_shape);
roots.set(m_global_object);
roots.set(m_exception);
#define __JS_ENUMERATE(ClassName, snake_name, PrototypeName, ConstructorName) \
roots.set(m_##snake_name##_prototype);
JS_ENUMERATE_BUILTIN_TYPES
#undef __JS_ENUMERATE
if (m_last_value.is_cell())
roots.set(m_last_value.as_cell());
for (auto& scope : m_scope_stack) {
for (auto& it : scope.variables) {
if (it.value.value.is_cell())
roots.set(it.value.value.as_cell());
}
}
for (auto& call_frame : m_call_stack) {
if (call_frame.this_value.is_cell())
roots.set(call_frame.this_value.as_cell());
for (auto& argument : call_frame.arguments) {
if (argument.is_cell())
roots.set(argument.as_cell());
}
}
}
Value Interpreter::call(Function* function, Value this_value, const Vector<Value>& arguments)
{
auto& call_frame = push_call_frame();
call_frame.function_name = function->name();
call_frame.this_value = this_value;
call_frame.arguments = arguments;
auto result = function->call(*this);
pop_call_frame();
return result;
}
Value Interpreter::throw_exception(Exception* exception)
{
if (exception->value().is_object() && exception->value().as_object().is_error()) {
auto& error = static_cast<Error&>(exception->value().as_object());
dbg() << "Throwing JavaScript Error: " << error.name() << ", " << error.message();
}
m_exception = exception;
unwind(ScopeType::Try);
return {};
}
GlobalObject& Interpreter::global_object()
{
return static_cast<GlobalObject&>(*m_global_object);
}
const GlobalObject& Interpreter::global_object() const
{
return static_cast<const GlobalObject&>(*m_global_object);
}
}
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