LibJS: Add spec comments to DataViewPrototype

1 files changed, 145 insertions, 25 deletions

diff --git a/Userland/Libraries/LibJS/Runtime/DataViewPrototype.cpp b/Userland/Libraries/LibJS/Runtime/DataViewPrototype.cpp
index 5fb6cc62f6..102ca0ef4e 100644
--- a/Userland/Libraries/LibJS/Runtime/DataViewPrototype.cpp
+++ b/Userland/Libraries/LibJS/Runtime/DataViewPrototype.cpp
@@ -54,28 +54,44 @@ void DataViewPrototype::initialize(Realm& realm)
 template<typename T>
 static ThrowCompletionOr<Value> get_view_value(VM& vm, Value request_index, Value is_little_endian)
 {
+    // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
+    // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
     auto* view = TRY(DataViewPrototype::typed_this_value(vm));
+
+    // 3. Let getIndex be ? ToIndex(requestIndex).
     auto get_index = TRY(request_index.to_index(vm));
+
+    // 4. Set isLittleEndian to ToBoolean(isLittleEndian).
     auto little_endian = is_little_endian.to_boolean();
 
+    // 5. Let buffer be view.[[ViewedArrayBuffer]].
     auto buffer = view->viewed_array_buffer();
+
+    // 6. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
     if (buffer->is_detached())
         return vm.template throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
 
+    // 7. Let viewOffset be view.[[ByteOffset]].
     auto view_offset = view->byte_offset();
+
+    // 8. Let viewSize be view.[[ByteLength]].
     auto view_size = view->byte_length();
 
+    // 9. Let elementSize be the Element Size value specified in Table 68 for Element Type type.
     auto element_size = sizeof(T);
 
+    // 11. Let bufferIndex be getIndex + viewOffset.
     Checked<size_t> buffer_index = get_index;
     buffer_index += view_offset;
 
     Checked<size_t> end_index = get_index;
     end_index += element_size;
 
+    // 10. If getIndex + elementSize > viewSize, throw a RangeError exception.
     if (buffer_index.has_overflow() || end_index.has_overflow() || end_index.value() > view_size)
         return vm.throw_completion<RangeError>(ErrorType::DataViewOutOfRangeByteOffset, get_index, view_size);
 
+    // 12. Return GetValueFromBuffer(buffer, bufferIndex, type, false, Unordered, isLittleEndian).
     return buffer->get_value<T>(buffer_index.value(), false, ArrayBuffer::Order::Unordered, little_endian);
 }
 
@@ -83,174 +99,278 @@ static ThrowCompletionOr<Value> get_view_value(VM& vm, Value request_index, Valu
 template<typename T>
 static ThrowCompletionOr<Value> set_view_value(VM& vm, Value request_index, Value is_little_endian, Value value)
 {
+    // 1. Perform ? RequireInternalSlot(view, [[DataView]]).
+    // 2. Assert: view has a [[ViewedArrayBuffer]] internal slot.
     auto* view = TRY(DataViewPrototype::typed_this_value(vm));
+
+    // 3. Let getIndex be ? ToIndex(requestIndex).
     auto get_index = TRY(request_index.to_index(vm));
 
     Value number_value;
+
+    // 4. If IsBigIntElementType(type) is true, let numberValue be ? ToBigInt(value).
     if constexpr (IsIntegral<T> && sizeof(T) == 8)
         number_value = TRY(value.to_bigint(vm));
+    // 5. Otherwise, let numberValue be ? ToNumber(value).
     else
         number_value = TRY(value.to_number(vm));
 
+    // 6. Set isLittleEndian to ToBoolean(isLittleEndian).
     auto little_endian = is_little_endian.to_boolean();
 
+    // 7. Let buffer be view.[[ViewedArrayBuffer]].
     auto buffer = view->viewed_array_buffer();
+
+    // 8. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
     if (buffer->is_detached())
         return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
 
+    // 9. Let viewOffset be view.[[ByteOffset]].
     auto view_offset = view->byte_offset();
+
+    // 10. Let viewSize be view.[[ByteLength]].
     auto view_size = view->byte_length();
 
+    // 11. Let elementSize be the Element Size value specified in Table 68 for Element Type type.
     auto element_size = sizeof(T);
 
+    // 13. Let bufferIndex be getIndex + viewOffset.
     Checked<size_t> buffer_index = get_index;
     buffer_index += view_offset;
 
     Checked<size_t> end_index = get_index;
     end_index += element_size;
 
+    // 12. If getIndex + elementSize > viewSize, throw a RangeError exception.
     if (buffer_index.has_overflow() || end_index.has_overflow() || end_index.value() > view_size)
         return vm.throw_completion<RangeError>(ErrorType::DataViewOutOfRangeByteOffset, get_index, view_size);
 
+    // 14. Perform SetValueInBuffer(buffer, bufferIndex, type, numberValue, false, Unordered, isLittleEndian).
     buffer->set_value<T>(buffer_index.value(), number_value, false, ArrayBuffer::Order::Unordered, little_endian);
 
+    // 15. Return undefined.
     return js_undefined();
 }
 
+// 25.3.4.1 get DataView.prototype.buffer, https://tc39.es/ecma262/#sec-get-dataview.prototype.buffer
+JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::buffer_getter)
+{
+    // 1. Let O be the this value.
+    // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
+    // 3. Assert: O has a [[ViewedArrayBuffer]] internal slot.
+    auto* data_view = TRY(typed_this_value(vm));
+
+    // 4. Let buffer be O.[[ViewedArrayBuffer]].
+    // 5. Return buffer.
+    return data_view->viewed_array_buffer();
+}
+
+// 25.3.4.2 get DataView.prototype.byteLength, https://tc39.es/ecma262/#sec-get-dataview.prototype.bytelength
+JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::byte_length_getter)
+{
+    // 1. Let O be the this value.
+    // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
+    // 3. Assert: O has a [[ViewedArrayBuffer]] internal slot.
+    auto* data_view = TRY(typed_this_value(vm));
+
+    // 4. Let buffer be O.[[ViewedArrayBuffer]].
+    // 5. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+    if (data_view->viewed_array_buffer()->is_detached())
+        return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
+
+    // 6. Let size be O.[[ByteLength]].
+    // 7. Return 𝔽(size).
+    return Value(data_view->byte_length());
+}
+
+// 25.3.4.3 get DataView.prototype.byteOffset, https://tc39.es/ecma262/#sec-get-dataview.prototype.byteoffset
+JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::byte_offset_getter)
+{
+    // 1. Let O be the this value.
+    // 2. Perform ? RequireInternalSlot(O, [[DataView]]).
+    // 3. Assert: O has a [[ViewedArrayBuffer]] internal slot.
+    auto* data_view = TRY(typed_this_value(vm));
+
+    // 4. Let buffer be O.[[ViewedArrayBuffer]].
+    // 5. If IsDetachedBuffer(buffer) is true, throw a TypeError exception.
+    if (data_view->viewed_array_buffer()->is_detached())
+        return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
+
+    // 6. Let offset be O.[[ByteOffset]].
+    // 7. Return 𝔽(offset).
+    return Value(data_view->byte_offset());
+}
+
 // 25.3.4.5 DataView.prototype.getBigInt64 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getbigint64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_big_int_64)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigInt64).
     return get_view_value<i64>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.6 DataView.prototype.getBigUint64 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getbiguint64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_big_uint_64)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? GetViewValue(v, byteOffset, littleEndian, BigUint64).
     return get_view_value<u64>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.7 DataView.prototype.getFloat32 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getfloat32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_float_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Float32).
     return get_view_value<float>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.8 DataView.prototype.getFloat64 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getfloat64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_float_64)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Float64).
     return get_view_value<double>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.9 DataView.prototype.getInt8 ( byteOffset ), https://tc39.es/ecma262/#sec-dataview.prototype.getint8
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_int_8)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? GetViewValue(v, byteOffset, true, Int8).
     return get_view_value<i8>(vm, vm.argument(0), Value(true));
 }
 
 // 25.3.4.10 DataView.prototype.getInt16 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getint16
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_int_16)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Int16).
     return get_view_value<i16>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.11 DataView.prototype.getInt32 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getint32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_int_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Int32).
     return get_view_value<i32>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.12 DataView.prototype.getUint8 ( byteOffset ), https://tc39.es/ecma262/#sec-dataview.prototype.getuint8
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_uint_8)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? GetViewValue(v, byteOffset, true, Uint8).
     return get_view_value<u8>(vm, vm.argument(0), Value(true));
 }
 
 // 25.3.4.13 DataView.prototype.getUint16 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getuint16
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_uint_16)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Uint16).
     return get_view_value<u16>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.14 DataView.prototype.getUint32 ( byteOffset [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.getuint32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::get_uint_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? GetViewValue(v, byteOffset, littleEndian, Uint32).
     return get_view_value<u32>(vm, vm.argument(0), vm.argument(1));
 }
 
 // 25.3.4.15 DataView.prototype.setBigInt64 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setbigint64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_big_int_64)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? SetViewValue(v, byteOffset, littleEndian, BigInt64, value).
     return set_view_value<i64>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.16 DataView.prototype.setBigUint64 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setbiguint64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_big_uint_64)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? SetViewValue(v, byteOffset, littleEndian, BigUint64, value).
     return set_view_value<u64>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.17 DataView.prototype.setFloat32 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setfloat32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_float_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Float32, value).
     return set_view_value<float>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.18 DataView.prototype.setFloat64 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setfloat64
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_float_64)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Float64, value).
     return set_view_value<double>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.19 DataView.prototype.setInt8 ( byteOffset, value ), https://tc39.es/ecma262/#sec-dataview.prototype.setint8
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_int_8)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? SetViewValue(v, byteOffset, true, Int8, value).
     return set_view_value<i8>(vm, vm.argument(0), Value(true), vm.argument(1));
 }
 
+// 25.3.4.20 DataView.prototype.setInt16 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setint16
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_int_16)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Int16, value).
     return set_view_value<i16>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.21 DataView.prototype.setInt32 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setint32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_int_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Int32, value).
     return set_view_value<i32>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.22 DataView.prototype.setUint8 ( byteOffset, value ), https://tc39.es/ecma262/#sec-dataview.prototype.setuint8
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_uint_8)
 {
+    // 1. Let v be the this value.
+    // 2. Return ? SetViewValue(v, byteOffset, true, Uint8, value).
     return set_view_value<u8>(vm, vm.argument(0), Value(true), vm.argument(1));
 }
 
+// 25.3.4.23 DataView.prototype.setUint16 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setuint16
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_uint_16)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Uint16, value).
     return set_view_value<u16>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
+// 25.3.4.24 DataView.prototype.setUint32 ( byteOffset, value [ , littleEndian ] ), https://tc39.es/ecma262/#sec-dataview.prototype.setuint32
 JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::set_uint_32)
 {
+    // 1. Let v be the this value.
+    // 2. If littleEndian is not present, set littleEndian to false.
+    // 3. Return ? SetViewValue(v, byteOffset, littleEndian, Uint32, value).
     return set_view_value<u32>(vm, vm.argument(0), vm.argument(2), vm.argument(1));
 }
 
-// 25.3.4.1 get DataView.prototype.buffer, https://tc39.es/ecma262/#sec-get-dataview.prototype.buffer
-JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::buffer_getter)
-{
-    auto* data_view = TRY(typed_this_value(vm));
-    return data_view->viewed_array_buffer();
-}
-
-// 25.3.4.2 get DataView.prototype.byteLength, https://tc39.es/ecma262/#sec-get-dataview.prototype.bytelength
-JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::byte_length_getter)
-{
-    auto* data_view = TRY(typed_this_value(vm));
-    if (data_view->viewed_array_buffer()->is_detached())
-        return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
-    return Value(data_view->byte_length());
-}
-
-// 25.3.4.3 get DataView.prototype.byteOffset, https://tc39.es/ecma262/#sec-get-dataview.prototype.byteoffset
-JS_DEFINE_NATIVE_FUNCTION(DataViewPrototype::byte_offset_getter)
-{
-    auto* data_view = TRY(typed_this_value(vm));
-    if (data_view->viewed_array_buffer()->is_detached())
-        return vm.throw_completion<TypeError>(ErrorType::DetachedArrayBuffer);
-    return Value(data_view->byte_offset());
-}
-
 }