LibJS: Implement Uint8Array.prototype.setFromHex

Author: https://github.com/trflynn89
Commit: https://github.com/LadybirdBrowser/ladybird/commit/7d0e33cb27f
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/1258
Reviewed-by: https://github.com/awesomekling

Userland/Libraries/LibJS/Runtime/CommonPropertyNames.h

@@ -464,6 +464,7 @@ namespace JS {
     P(setFloat32)                            \
     P(setFloat64)                            \
     P(setFromBase64)                         \
+    P(setFromHex)                            \
     P(setFullYear)                           \
     P(setHours)                              \
     P(setInt8)                               \

Userland/Libraries/LibJS/Runtime/Uint8Array.cpp

@@ -32,6 +32,7 @@ void Uint8ArrayPrototypeHelpers::initialize(Realm& realm, Object& prototype)
     prototype.define_native_function(realm, vm.names.toBase64, to_base64, 0, attr);
     prototype.define_native_function(realm, vm.names.toHex, to_hex, 0, attr);
     prototype.define_native_function(realm, vm.names.setFromBase64, set_from_base64, 1, attr);
+    prototype.define_native_function(realm, vm.names.setFromHex, set_from_hex, 1, attr);
 }
 
 static ThrowCompletionOr<Alphabet> parse_alphabet(VM& vm, Object& options)
@@ -307,6 +308,66 @@ JS_DEFINE_NATIVE_FUNCTION(Uint8ArrayConstructorHelpers::from_hex)
     return typed_array;
 }
 
+// 6 Uint8Array.prototype.setFromHex ( string ), https://tc39.es/proposal-arraybuffer-base64/spec/#sec-uint8array.prototype.setfromhex
+JS_DEFINE_NATIVE_FUNCTION(Uint8ArrayPrototypeHelpers::set_from_hex)
+{
+    auto& realm = *vm.current_realm();
+
+    auto string_value = vm.argument(0);
+
+    // 1. Let into be the this value.
+    // 2. Perform ? ValidateUint8Array(into).
+    auto into = TRY(validate_uint8_array(vm));
+
+    // 3. If string is not a String, throw a TypeError exception.
+    if (!string_value.is_string())
+        return vm.throw_completion<TypeError>(ErrorType::NotAString, string_value);
+
+    // 4. Let taRecord be MakeTypedArrayWithBufferWitnessRecord(into, seq-cst).
+    auto typed_array_record = make_typed_array_with_buffer_witness_record(into, ArrayBuffer::Order::SeqCst);
+
+    // 5. If IsTypedArrayOutOfBounds(taRecord) is true, throw a TypeError exception.
+    if (is_typed_array_out_of_bounds(typed_array_record))
+        return vm.throw_completion<TypeError>(ErrorType::BufferOutOfBounds, "TypedArray"sv);
+
+    // 6. Let byteLength be TypedArrayLength(taRecord).
+    auto byte_length = typed_array_length(typed_array_record);
+
+    // 7. Let result be FromHex(string, byteLength).
+    auto result = JS::from_hex(vm, string_value.as_string().utf8_string_view(), byte_length);
+
+    // 8. Let bytes be result.[[Bytes]].
+    auto bytes = move(result.bytes);
+
+    // 9. Let written be the length of bytes.
+    auto written = bytes.size();
+
+    // 10. NOTE: FromHex does not invoke any user code, so the ArrayBuffer backing into cannot have been detached or shrunk.
+    // 11. Assert: written ≤ byteLength.
+    VERIFY(written <= byte_length);
+
+    // 12. Perform SetUint8ArrayBytes(into, bytes).
+    set_uint8_array_bytes(into, bytes);
+
+    // 13. If result.[[Error]] is not none, then
+    if (result.error.has_value()) {
+        // a. Throw result.[[Error]].
+        return result.error.release_value();
+    }
+
+    // 14. Let resultObject be OrdinaryObjectCreate(%Object.prototype%).
+    auto result_object = Object::create(realm, realm.intrinsics().object_prototype());
+
+    // 15. Perform ! CreateDataPropertyOrThrow(resultObject, "read", 𝔽(result.[[Read]])).
+    MUST(result_object->create_data_property(vm.names.read, Value { result.read }));
+
+    // 16. Perform ! CreateDataPropertyOrThrow(resultObject, "written", 𝔽(written)).
+    MUST(result_object->create_data_property(vm.names.written, Value { written }));
+
+    // 17. Return resultObject.
+    return result_object;
+}
+
 // 7 ValidateUint8Array ( ta ), https://tc39.es/proposal-arraybuffer-base64/spec/#sec-validateuint8array
 ThrowCompletionOr<NonnullGCPtr<TypedArrayBase>> validate_uint8_array(VM& vm)
 {

Userland/Libraries/LibJS/Runtime/Uint8Array.h

@@ -33,6 +33,7 @@ private:
     JS_DECLARE_NATIVE_FUNCTION(to_base64);
     JS_DECLARE_NATIVE_FUNCTION(to_hex);
     JS_DECLARE_NATIVE_FUNCTION(set_from_base64);
+    JS_DECLARE_NATIVE_FUNCTION(set_from_hex);
 };
 
 enum class Alphabet {

Userland/Libraries/LibJS/Tests/builtins/TypedArray/Uint8Array.prototype.setFromHex.js

@@ -0,0 +1,84 @@
+describe("errors", () => {
+    test("called on non-Uint8Array object", () => {
+        expect(() => {
+            Uint8Array.prototype.setFromHex.call("");
+        }).toThrowWithMessage(TypeError, "Not an object of type Uint8Array");
+
+        expect(() => {
+            Uint8Array.prototype.setFromHex.call(new Uint16Array());
+        }).toThrowWithMessage(TypeError, "Not an object of type Uint8Array");
+    });
+
+    test("detached ArrayBuffer", () => {
+        let arrayBuffer = new ArrayBuffer(5, { maxByteLength: 10 });
+        let typedArray = new Uint8Array(arrayBuffer, Uint8Array.BYTES_PER_ELEMENT, 1);
+        detachArrayBuffer(arrayBuffer);
+
+        expect(() => {
+            typedArray.setFromHex("");
+        }).toThrowWithMessage(
+            TypeError,
+            "TypedArray contains a property which references a value at an index not contained within its buffer's bounds"
+        );
+    });
+
+    test("ArrayBuffer out of bounds", () => {
+        let arrayBuffer = new ArrayBuffer(Uint8Array.BYTES_PER_ELEMENT * 2, {
+            maxByteLength: Uint8Array.BYTES_PER_ELEMENT * 4,
+        });
+
+        let typedArray = new Uint8Array(arrayBuffer, Uint8Array.BYTES_PER_ELEMENT, 1);
+        arrayBuffer.resize(Uint8Array.BYTES_PER_ELEMENT);
+
+        expect(() => {
+            typedArray.setFromHex("");
+        }).toThrowWithMessage(
+            TypeError,
+            "TypedArray contains a property which references a value at an index not contained within its buffer's bounds"
+        );
+    });
+
+    test("invalid string", () => {
+        expect(() => {
+            new Uint8Array(10).setFromHex(3.14);
+        }).toThrowWithMessage(TypeError, "3.14 is not a string");
+    });
+
+    test("odd number of characters", () => {
+        expect(() => {
+            new Uint8Array(10).setFromHex("a");
+        }).toThrowWithMessage(SyntaxError, "Hex string must have an even length");
+    });
+
+    test("invalid alphabet", () => {
+        expect(() => {
+            new Uint8Array(10).setFromHex("qq");
+        }).toThrowWithMessage(SyntaxError, "Hex string must only contain hex characters");
+    });
+});
+
+describe("correct behavior", () => {
+    test("length is 1", () => {
+        expect(Uint8Array.prototype.setFromHex).toHaveLength(1);
+    });
+
+    const decodeEqual = (input, expected) => {
+        expected = toUTF8Bytes(expected);
+
+        let array = new Uint8Array(expected.length);
+        let result = array.setFromHex(input);
+
+        expect(result.read).toBe(input.length);
+        expect(result.written).toBe(expected.length);
+
+        expect(array).toEqual(expected);
+    };
+
+    test("basic functionality", () => {
+        decodeEqual("", "");
+        decodeEqual("61", "a");
+        decodeEqual("616263646566303132333435", "abcdef012345");
+        decodeEqual("f09fa493", "🤓");
+        decodeEqual("f09fa493666f6ff09f9696", "🤓foo🖖");
+    });
+});