LibJS: Add getter/setter support

This patch adds a GetterSetterPair object. Values can now store pointers
to objects of this type. These objects are created when using
Object.defineProperty and providing an accessor descriptor.
This commit is contained in:
Matthew Olsson 2020-05-21 11:14:23 -07:00 committed by Andreas Kling
parent a4d04cc748
commit 45dfa094e9
Notes: sideshowbarker 2024-07-19 06:16:10 +09:00
7 changed files with 259 additions and 12 deletions

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@ -59,6 +59,7 @@ class DeferGC;
class Error;
class Exception;
class Expression;
class Accessor;
class GlobalObject;
class HandleImpl;
class Heap;

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@ -0,0 +1,79 @@
/*
* Copyright (c) 2020, Matthew Olsson <matthewcolsson@gmail.com>
* 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 <LibJS/Runtime/Cell.h>
#include <LibJS/Runtime/Value.h>
namespace JS {
class Accessor final : public Cell {
public:
static Accessor* create(Interpreter& interpreter, Value getter, Value setter)
{
return interpreter.heap().allocate<Accessor>(getter, setter);
}
Accessor(Value getter, Value setter)
: m_getter(getter)
, m_setter(setter)
{
}
Value getter() { return m_getter; }
Value setter() { return m_setter; }
Value call_getter(Value this_object)
{
if (!getter().is_function())
return js_undefined();
return interpreter().call(getter().as_function(), this_object);
}
void call_setter(Value this_object, Value setter_value)
{
if (!setter().is_function())
return;
MarkedValueList arguments(interpreter().heap());
arguments.values().append(setter_value);
interpreter().call(setter().as_function(), this_object, move(arguments));
}
void visit_children(Cell::Visitor& visitor) override
{
visitor.visit(m_getter);
visitor.visit(m_setter);
}
private:
const char* class_name() const override { return "Accessor"; };
Value m_getter;
Value m_setter;
};
}

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@ -27,6 +27,7 @@
#include <AK/String.h>
#include <LibJS/Heap/Heap.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/Accessor.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/Error.h>
#include <LibJS/Runtime/GlobalObject.h>
@ -96,6 +97,9 @@ Value Object::get_own_property(const Object& this_object, const FlyString& prope
auto value_here = m_storage[metadata.value().offset];
ASSERT(!value_here.is_empty());
if (value_here.is_accessor()) {
return value_here.as_accessor().call_getter(Value(const_cast<Object*>(this)));
}
if (value_here.is_object() && value_here.as_object().is_native_property()) {
auto& native_property = static_cast<const NativeProperty&>(value_here.as_object());
auto& interpreter = const_cast<Object*>(this)->interpreter();
@ -180,10 +184,16 @@ Value Object::get_own_property_descriptor(const FlyString& property_name) const
if (interpreter().exception())
return {};
auto* descriptor = Object::create_empty(interpreter(), interpreter().global_object());
descriptor->put("value", value.value_or(js_undefined()));
descriptor->put("writable", Value(!!(metadata.value().attributes & Attribute::Writable)));
descriptor->put("enumerable", Value(!!(metadata.value().attributes & Attribute::Enumerable)));
descriptor->put("configurable", Value(!!(metadata.value().attributes & Attribute::Configurable)));
descriptor->put("enumerable", Value((metadata.value().attributes & Attribute::Enumerable) != 0));
descriptor->put("configurable", Value((metadata.value().attributes & Attribute::Configurable) != 0));
if (value.is_accessor()) {
auto& pair = value.as_accessor();
descriptor->put("get", pair.getter());
descriptor->put("set", pair.setter());
} else {
descriptor->put("value", value.value_or(js_undefined()));
descriptor->put("writable", Value((metadata.value().attributes & Attribute::Writable) != 0));
}
return descriptor;
}
@ -195,19 +205,74 @@ void Object::set_shape(Shape& new_shape)
bool Object::define_property(const FlyString& property_name, const Object& descriptor, bool throw_exceptions)
{
auto value = descriptor.get("value");
bool is_accessor_property = descriptor.has_property("get") || descriptor.has_property("set");
u8 configurable = descriptor.get("configurable").value_or(Value(false)).to_boolean() * Attribute::Configurable;
if (interpreter().exception())
return {};
u8 enumerable = descriptor.get("enumerable").value_or(Value(false)).to_boolean() * Attribute::Enumerable;
u8 writable = descriptor.get("writable").value_or(Value(false)).to_boolean() * Attribute::Writable;
u8 attributes = configurable | enumerable | writable;
if (interpreter().exception())
return {};
u8 attributes = configurable | enumerable;
dbg() << "Defining new property " << property_name << " with descriptor { " << configurable << ", " << enumerable << ", " << writable << ", attributes=" << attributes << " }";
if (is_accessor_property) {
if (descriptor.has_property("value") || descriptor.has_property("writable")) {
if (throw_exceptions)
interpreter().throw_exception<TypeError>("Accessor property descriptors cannot specify a value or writable key");
return false;
}
auto getter = descriptor.get("get");
if (interpreter().exception())
return {};
auto setter = descriptor.get("set");
if (interpreter().exception())
return {};
if (!(getter.is_empty() || getter.is_undefined() || getter.is_function())) {
interpreter().throw_exception<TypeError>("Accessor descriptor's 'get' field must be a function or undefined");
return false;
}
if (!(setter.is_empty() || setter.is_undefined() || setter.is_function())) {
interpreter().throw_exception<TypeError>("Accessor descriptor's 'set' field must be a function or undefined");
return false;
}
// FIXME: Throw a TypeError if the setter does not take any arguments
dbg() << "Defining new property " << property_name << " with accessor descriptor { attributes=" << attributes
<< " , getter=" << (getter.is_empty() ? "<empty>" : getter.to_string_without_side_effects())
<< ", setter=" << (setter.is_empty() ? "<empty>" : setter.to_string_without_side_effects()) << "}";
return put_own_property(*this, property_name, attributes, Accessor::create(interpreter(), getter, setter), PutOwnPropertyMode::DefineProperty, throw_exceptions);
}
auto value = descriptor.get("value");
if (interpreter().exception())
return {};
u8 writable = descriptor.get("writable").value_or(Value(false)).to_boolean() * Attribute::Writable;
if (interpreter().exception())
return {};
attributes |= writable;
dbg() << "Defining new property " << property_name << " with data descriptor { attributes=" << attributes
<< ", value=" << (value.is_empty() ? "<empty>" : value.to_string_without_side_effects()) << " }";
return put_own_property(*this, property_name, attributes, value, PutOwnPropertyMode::DefineProperty, throw_exceptions);
}
bool Object::put_own_property(Object& this_object, const FlyString& property_name, u8 attributes, Value value, PutOwnPropertyMode mode, bool throw_exceptions)
{
ASSERT(!(mode == PutOwnPropertyMode::Put && value.is_accessor()));
if (value.is_accessor()) {
auto& accessor = value.as_accessor();
if (accessor.getter().is_function())
attributes |= Attribute::HasGet;
if (accessor.setter().is_function())
attributes |= Attribute::HasSet;
}
auto metadata = shape().lookup(property_name);
bool new_property = !metadata.has_value();
@ -231,7 +296,7 @@ bool Object::put_own_property(Object& this_object, const FlyString& property_nam
if (!new_property && mode == PutOwnPropertyMode::DefineProperty && !(metadata.value().attributes & Attribute::Configurable) && attributes != metadata.value().attributes) {
dbg() << "Disallow reconfig of non-configurable property";
if (throw_exceptions)
interpreter().throw_exception<TypeError>(String::format("Cannot redefine property '%s'", property_name.characters()));
interpreter().throw_exception<TypeError>(String::format("Cannot change attributes of non-configurable property '%s'", property_name.characters()));
return false;
}
@ -246,7 +311,8 @@ bool Object::put_own_property(Object& this_object, const FlyString& property_nam
dbg() << "Reconfigured property " << property_name << ", new shape says offset is " << metadata.value().offset << " and my storage capacity is " << m_storage.size();
}
if (!new_property && mode == PutOwnPropertyMode::Put && !(metadata.value().attributes & Attribute::Writable)) {
auto value_here = m_storage[metadata.value().offset];
if (!new_property && mode == PutOwnPropertyMode::Put && !value_here.is_accessor() && !(metadata.value().attributes & Attribute::Writable)) {
dbg() << "Disallow write to non-writable property";
return false;
}
@ -254,7 +320,6 @@ bool Object::put_own_property(Object& this_object, const FlyString& property_nam
if (value.is_empty())
return true;
auto value_here = m_storage[metadata.value().offset];
if (value_here.is_object() && value_here.as_object().is_native_property()) {
auto& native_property = static_cast<NativeProperty&>(value_here.as_object());
auto& interpreter = const_cast<Object*>(this)->interpreter();
@ -377,6 +442,10 @@ bool Object::put(const FlyString& property_name, Value value, u8 attributes)
auto metadata = object->shape().lookup(property_name);
if (metadata.has_value()) {
auto value_here = object->m_storage[metadata.value().offset];
if (value_here.is_accessor()) {
value_here.as_accessor().call_setter(Value(this), value);
return true;
}
if (value_here.is_object() && value_here.as_object().is_native_property()) {
auto& native_property = static_cast<NativeProperty&>(value_here.as_object());
auto& interpreter = const_cast<Object*>(this)->interpreter();

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@ -40,6 +40,8 @@ struct Attribute {
Configurable = 1 << 0,
Enumerable = 1 << 1,
Writable = 1 << 2,
HasGet = 1 << 3,
HasSet = 1 << 4,
};
};

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@ -29,6 +29,7 @@
#include <AK/StringBuilder.h>
#include <LibJS/Heap/Heap.h>
#include <LibJS/Interpreter.h>
#include <LibJS/Runtime/Accessor.h>
#include <LibJS/Runtime/Array.h>
#include <LibJS/Runtime/BooleanObject.h>
#include <LibJS/Runtime/Error.h>
@ -63,6 +64,12 @@ Function& Value::as_function()
return static_cast<Function&>(as_object());
}
Accessor& Value::as_accessor()
{
ASSERT(is_accessor());
return static_cast<Accessor&>(*m_value.as_accessor);
}
String Value::to_string_without_side_effects() const
{
if (is_boolean())
@ -92,6 +99,9 @@ String Value::to_string_without_side_effects() const
if (is_symbol())
return as_symbol().to_string();
if (is_accessor())
return "<accessor>";
ASSERT(is_object());
return String::format("[object %s]", as_object().class_name());
}
@ -205,6 +215,7 @@ Value Value::to_number(Interpreter& interpreter) const
{
switch (m_type) {
case Type::Empty:
case Type::Accessor:
ASSERT_NOT_REACHED();
return {};
case Type::Undefined:

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@ -45,6 +45,7 @@ public:
Object,
Boolean,
Symbol,
Accessor,
};
bool is_empty() const { return m_type == Type::Empty; }
@ -55,7 +56,8 @@ public:
bool is_object() const { return m_type == Type::Object; }
bool is_boolean() const { return m_type == Type::Boolean; }
bool is_symbol() const { return m_type == Type::Symbol; }
bool is_cell() const { return is_string() || is_object(); }
bool is_accessor() const { return m_type == Type::Accessor; };
bool is_cell() const { return is_string() || is_accessor() || is_object(); }
bool is_array() const;
bool is_function() const;
@ -119,6 +121,12 @@ public:
m_value.as_symbol = symbol;
}
Value(Accessor* accessor)
: m_type(Type::Accessor)
{
m_value.as_accessor = accessor;
}
explicit Value(Type type)
: m_type(type)
{
@ -183,6 +191,7 @@ public:
String to_string_without_side_effects() const;
Function& as_function();
Accessor& as_accessor();
i32 as_i32() const;
size_t as_size_t() const;
@ -214,6 +223,7 @@ private:
Symbol* as_symbol;
Object* as_object;
Cell* as_cell;
Accessor* as_accessor;
} m_value;
};

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@ -40,6 +40,81 @@ try {
assert(d.writable === true);
assert(d.value === 9);
Object.defineProperty(o, "qux", {
configurable: true,
get() {
return o.secret_qux + 1;
},
set(value) {
this.secret_qux = value + 1;
},
});
o.qux = 10;
assert(o.qux === 12);
o.qux = 20;
assert(o.qux = 22);
Object.defineProperty(o, "qux", { configurable: true, value: 4 });
assert(o.qux === 4);
o.qux = 5;
assert(o.qux = 4);
Object.defineProperty(o, "qux", {
configurable: false,
get() {
return this.secret_qux + 2;
},
set(value) {
o.secret_qux = value + 2;
},
});
o.qux = 10;
assert(o.qux === 14);
o.qux = 20;
assert(o.qux = 24);
assertThrowsError(() => {
Object.defineProperty(o, "qux", {
configurable: false,
get() {
return this.secret_qux + 2;
},
});
}, {
error: TypeError,
message: "Cannot change attributes of non-configurable property 'qux'",
});
assertThrowsError(() => {
Object.defineProperty(o, "qux", { value: 2 });
}, {
error: TypeError,
message: "Cannot change attributes of non-configurable property 'qux'",
});
assertThrowsError(() => {
Object.defineProperty(o, "a", {
get() {},
value: 9,
});
}, {
error: TypeError,
message: "Accessor property descriptors cannot specify a value or writable key",
});
assertThrowsError(() => {
Object.defineProperty(o, "a", {
set() {},
writable: true,
});
}, {
error: TypeError,
message: "Accessor property descriptors cannot specify a value or writable key",
});
console.log("PASS");
} catch (e) {
console.log(e)