ladybird/Libraries/LibJS/Runtime/FunctionConstructor.cpp
Linus Groh a10d09faba LibJS: Tweak generated source in 'new Function()' to match ES 2015 spec
ES 5(.1) described parsing of the function body string as:

https://www.ecma-international.org/ecma-262/5.1/#sec-15.3.2.1

7. If P is not parsable as a FormalParameterList[opt] then throw a SyntaxError exception.
8. If body is not parsable as FunctionBody then throw a SyntaxError exception.

We implemented it as building the source string of a complete function
and feeding that to the parser, with the same outcome. ES 2015+ does
exactly that, but with newlines at certain positions:

https://tc39.es/ecma262/#sec-createdynamicfunction

16. Let bodyString be the string-concatenation of 0x000A (LINE FEED), ? ToString(bodyArg), and 0x000A (LINE FEED).
17. Let prefix be the prefix associated with kind in Table 49.
18. Let sourceString be the string-concatenation of prefix, " anonymous(", P, 0x000A (LINE FEED), ") {", bodyString, and "}".

This patch updates the generated source string to match these
requirements. This will make certain edge cases work, e.g.
'new Function("-->")', where the user supplied input must be placed on
its own line to be valid syntax.
2020-10-29 22:27:55 +01:00

105 lines
3.8 KiB
C++

/*
* Copyright (c) 2020, Linus Groh <mail@linusgroh.de>
* 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/StringBuilder.h>
#include <LibJS/AST.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Parser.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/FunctionConstructor.h>
#include <LibJS/Runtime/GlobalObject.h>
#include <LibJS/Runtime/ScriptFunction.h>
namespace JS {
FunctionConstructor::FunctionConstructor(GlobalObject& global_object)
: NativeFunction(vm().names.Function, *global_object.function_prototype())
{
}
void FunctionConstructor::initialize(GlobalObject& global_object)
{
auto& vm = this->vm();
NativeFunction::initialize(global_object);
define_property(vm.names.prototype, global_object.function_prototype(), 0);
define_property(vm.names.length, Value(1), Attribute::Configurable);
}
FunctionConstructor::~FunctionConstructor()
{
}
Value FunctionConstructor::call()
{
return construct(*this);
}
Value FunctionConstructor::construct(Function&)
{
auto& vm = this->vm();
String parameters_source = "";
String body_source = "";
if (vm.argument_count() == 1) {
body_source = vm.argument(0).to_string(global_object());
if (vm.exception())
return {};
}
if (vm.argument_count() > 1) {
Vector<String> parameters;
for (size_t i = 0; i < vm.argument_count() - 1; ++i) {
parameters.append(vm.argument(i).to_string(global_object()));
if (vm.exception())
return {};
}
StringBuilder parameters_builder;
parameters_builder.join(',', parameters);
parameters_source = parameters_builder.build();
body_source = vm.argument(vm.argument_count() - 1).to_string(global_object());
if (vm.exception())
return {};
}
auto source = String::formatted("function anonymous({}\n) {{\n{}\n}}", parameters_source, body_source);
auto parser = Parser(Lexer(source));
auto function_expression = parser.parse_function_node<FunctionExpression>();
if (parser.has_errors()) {
auto error = parser.errors()[0];
vm.throw_exception<SyntaxError>(global_object(), error.to_string());
return {};
}
OwnPtr<Interpreter> local_interpreter;
Interpreter* interpreter = vm.interpreter_if_exists();
if (!interpreter) {
local_interpreter = Interpreter::create_with_existing_global_object(global_object());
interpreter = local_interpreter.ptr();
}
VM::InterpreterExecutionScope scope(*interpreter);
return function_expression->execute(*interpreter, global_object());
}
}