mirror of
https://github.com/RGBCube/serenity
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3a184f7841
The spec version of canonical_numeric_index_string is absurdly complex, and ends up converting from a string to a number, and then back again which is both slow and also requires a few allocations and a string compare. Instead lets use the logic we already have as that is much more efficient. This improves performance of all non-numeric property names.
112 lines
4 KiB
C++
112 lines
4 KiB
C++
/*
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* Copyright (c) 2021, Luke Wilde <lukew@serenityos.org>
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* Copyright (c) 2021, Linus Groh <linusg@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/ByteBuffer.h>
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#include <AK/NumericLimits.h>
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#include <LibJS/Runtime/AbstractOperations.h>
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#include <LibJS/Runtime/ArrayBuffer.h>
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#include <LibJS/Runtime/DataView.h>
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#include <LibJS/Runtime/PropertyKey.h>
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#include <LibJS/Runtime/TypedArray.h>
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#include <LibWeb/Bindings/IDLAbstractOperations.h>
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namespace Web::Bindings::IDL {
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// https://webidl.spec.whatwg.org/#is-an-array-index
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bool is_an_array_index(JS::PropertyKey const& property_name)
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{
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// 1. If Type(P) is not String, then return false.
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if (!property_name.is_number())
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return false;
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// 2. Let index be ! CanonicalNumericIndexString(P).
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auto index = JS::canonical_numeric_index_string(property_name);
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if (!index.has_value()) {
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// All of these are handled by canonical_numeric_index_string
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// 3. If index is undefined, then return false.
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// 4. If IsInteger(index) is false, then return false.
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// 5. If index is −0, then return false.
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// 6. If index < 0, then return false.
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// 7. If index ≥ 2 ** 32 − 1, then return false.
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// Note: 2 ** 32 − 1 is the maximum array length allowed by ECMAScript.
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return false;
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}
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// 8. Return true.
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return true;
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}
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// https://webidl.spec.whatwg.org/#dfn-get-buffer-source-copy
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Optional<ByteBuffer> get_buffer_source_copy(JS::Object const& buffer_source)
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{
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// 1. Let esBufferSource be the result of converting bufferSource to an ECMAScript value.
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// 2. Let esArrayBuffer be esBufferSource.
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JS::ArrayBuffer* es_array_buffer;
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// 3. Let offset be 0.
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u32 offset = 0;
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// 4. Let length be 0.
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u32 length = 0;
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// 5. If esBufferSource has a [[ViewedArrayBuffer]] internal slot, then:
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if (is<JS::TypedArrayBase>(buffer_source)) {
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auto const& es_buffer_source = static_cast<JS::TypedArrayBase const&>(buffer_source);
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// 1. Set esArrayBuffer to esBufferSource.[[ViewedArrayBuffer]].
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es_array_buffer = es_buffer_source.viewed_array_buffer();
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// 2. Set offset to esBufferSource.[[ByteOffset]].
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offset = es_buffer_source.byte_offset();
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// 3. Set length to esBufferSource.[[ByteLength]].
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length = es_buffer_source.byte_length();
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} else if (is<JS::DataView>(buffer_source)) {
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auto const& es_buffer_source = static_cast<JS::DataView const&>(buffer_source);
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// 1. Set esArrayBuffer to esBufferSource.[[ViewedArrayBuffer]].
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es_array_buffer = es_buffer_source.viewed_array_buffer();
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// 2. Set offset to esBufferSource.[[ByteOffset]].
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offset = es_buffer_source.byte_offset();
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// 3. Set length to esBufferSource.[[ByteLength]].
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length = es_buffer_source.byte_length();
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}
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// 6. Otherwise:
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else {
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// 1. Assert: esBufferSource is an ArrayBuffer or SharedArrayBuffer object.
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auto const& es_buffer_source = static_cast<JS::ArrayBuffer const&>(buffer_source);
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es_array_buffer = &const_cast<JS ::ArrayBuffer&>(es_buffer_source);
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// 2. Set length to esBufferSource.[[ArrayBufferByteLength]].
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length = es_buffer_source.byte_length();
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}
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// 7. If ! IsDetachedBuffer(esArrayBuffer) is true, then return the empty byte sequence.
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if (es_array_buffer->is_detached())
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return ByteBuffer {};
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// 8. Let bytes be a new byte sequence of length equal to length.
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auto bytes = ByteBuffer::create_zeroed(length);
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if (bytes.is_error())
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return {};
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// 9. For i in the range offset to offset + length − 1, inclusive, set bytes[i − offset] to ! GetValueFromBuffer(esArrayBuffer, i, Uint8, true, Unordered).
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for (u64 i = offset; i <= offset + length - 1; ++i) {
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auto value = es_array_buffer->get_value<u8>(i, true, JS::ArrayBuffer::Unordered);
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bytes.value()[i - offset] = (u8)value.as_u32();
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}
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// 10. Return bytes.
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return bytes.release_value();
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}
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}
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