LibWeb: Add the Web::Crypto namespace, built-in, and getRandomValues

Since we don't support IDL typedefs or unions yet, the responsibility
of verifying the type of the argument is temporarily moved from the
generated Wrapper to the implementation.

1 files changed, 37 insertions, 0 deletions

diff --git a/Userland/Libraries/LibWeb/Crypto/Crypto.cpp b/Userland/Libraries/LibWeb/Crypto/Crypto.cpp
new file mode 100644
index 0000000000..64ba54f6ed
--- /dev/null
+++ b/Userland/Libraries/LibWeb/Crypto/Crypto.cpp
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include <AK/Random.h>
+#include <LibJS/Runtime/TypedArray.h>
+#include <LibWeb/Bindings/Wrapper.h>
+#include <LibWeb/Crypto/Crypto.h>
+
+namespace Web::Crypto {
+
+DOM::ExceptionOr<JS::Value> Crypto::get_random_values(JS::Value array) const
+{
+    // 1. If array is not an Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array, then throw a TypeMismatchError and terminate the algorithm.
+    if (!array.is_object() || !(is<JS::Int8Array>(array.as_object()) || is<JS::Uint8Array>(array.as_object()) || is<JS::Uint8ClampedArray>(array.as_object()) || is<JS::Int16Array>(array.as_object()) || is<JS::Uint16Array>(array.as_object()) || is<JS::Int32Array>(array.as_object()) || is<JS::Uint32Array>(array.as_object()) || is<JS::BigInt64Array>(array.as_object()) || is<JS::BigUint64Array>(array.as_object())))
+        return DOM::TypeMismatchError::create("array must be one of Int8Array, Uint8Array, Uint8ClampedArray, Int16Array, Uint16Array, Int32Array, Uint32Array, BigInt64Array, or BigUint64Array");
+    auto& typed_array = static_cast<JS::TypedArrayBase&>(array.as_object());
+
+    // 2. If the byteLength of array is greater than 65536, throw a QuotaExceededError and terminate the algorithm.
+    if (typed_array.byte_length() > 65536)
+        return DOM::QuotaExceededError::create("array's byteLength may not be greater than 65536");
+
+    // IMPLEMENTATION DEFINED: If the viewed array buffer is detached, throw a InvalidStateError and terminate the algorithm.
+    if (typed_array.viewed_array_buffer()->is_detached())
+        return DOM::InvalidStateError::create("array is detached");
+    // FIXME: Handle SharedArrayBuffers
+
+    // 3. Overwrite all elements of array with cryptographically strong random values of the appropriate type.
+    fill_with_random(typed_array.viewed_array_buffer()->buffer().data(), typed_array.viewed_array_buffer()->buffer().size());
+
+    // 4. Return array.
+    return array;
+}
+
+}