c0d7f748ed
This commit introduces a WEB_SET_PROTOTYPE_FOR_INTERFACE macro that caches the interface name in a local static FlyString. This means that we only pay for FlyString-from-literal lookup once per browser lifetime instead of every time the interface is instantiated.
115 lines
3.9 KiB
C++
115 lines
3.9 KiB
C++
/*
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* Copyright (c) 2021-2022, 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 <LibJS/Runtime/TypedArray.h>
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#include <LibWeb/Bindings/Intrinsics.h>
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#include <LibWeb/Encoding/TextEncoder.h>
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#include <LibWeb/WebIDL/ExceptionOr.h>
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namespace Web::Encoding {
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JS_DEFINE_ALLOCATOR(TextEncoder);
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WebIDL::ExceptionOr<JS::NonnullGCPtr<TextEncoder>> TextEncoder::construct_impl(JS::Realm& realm)
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{
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return realm.heap().allocate<TextEncoder>(realm, realm);
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}
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TextEncoder::TextEncoder(JS::Realm& realm)
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: PlatformObject(realm)
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{
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}
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TextEncoder::~TextEncoder() = default;
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void TextEncoder::initialize(JS::Realm& realm)
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{
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Base::initialize(realm);
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WEB_SET_PROTOTYPE_FOR_INTERFACE(TextEncoder);
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}
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// https://encoding.spec.whatwg.org/#dom-textencoder-encode
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JS::NonnullGCPtr<JS::Uint8Array> TextEncoder::encode(String const& input) const
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{
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// NOTE: The AK::String is always UTF-8, so most of these steps are no-ops.
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// 1. Convert input to an I/O queue of scalar values.
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// 2. Let output be the I/O queue of bytes « end-of-queue ».
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// 3. While true:
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// 1. Let item be the result of reading from input.
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// 2. Let result be the result of processing an item with item, an instance of the UTF-8 encoder, input, output, and "fatal".
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// 3. Assert: result is not an error.
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// 4. If result is finished, then convert output into a byte sequence and return a Uint8Array object wrapping an ArrayBuffer containing output.
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auto byte_buffer = MUST(ByteBuffer::copy(input.bytes()));
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auto array_length = byte_buffer.size();
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auto array_buffer = JS::ArrayBuffer::create(realm(), move(byte_buffer));
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return JS::Uint8Array::create(realm(), array_length, *array_buffer);
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}
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// https://encoding.spec.whatwg.org/#dom-textencoder-encodeinto
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TextEncoderEncodeIntoResult TextEncoder::encode_into(String const& source, JS::Handle<WebIDL::BufferSource> const& destination) const
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{
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auto& data = destination->viewed_array_buffer()->buffer();
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// 1. Let read be 0.
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WebIDL::UnsignedLongLong read = 0;
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// 2. Let written be 0.
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WebIDL::UnsignedLongLong written = 0;
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// NOTE: The AK::String is always UTF-8, so most of these steps are no-ops.
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// 3. Let encoder be an instance of the UTF-8 encoder.
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// 4. Let unused be the I/O queue of scalar values « end-of-queue ».
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// 5. Convert source to an I/O queue of scalar values.
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auto code_points = source.code_points();
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auto it = code_points.begin();
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// 6. While true:
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while (true) {
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// 6.1. Let item be the result of reading from source.
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// 6.2. Let result be the result of running encoder’s handler on unused and item.
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// 6.3. If result is finished, then break.
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if (it.done())
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break;
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auto item = *it;
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auto result = it.underlying_code_point_bytes();
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// 6.4. Otherwise:
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// 6.4.1. If destination’s byte length − written is greater than or equal to the number of bytes in result, then:
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if (data.size() - written >= result.size()) {
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// 6.4.1.1. If item is greater than U+FFFF, then increment read by 2.
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if (item > 0xffff) {
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read += 2;
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}
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// 6.4.1.2. Otherwise, increment read by 1.
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else {
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read++;
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}
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// 6.4.1.3. Write the bytes in result into destination, with startingOffset set to written.
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// 6.4.1.4. Increment written by the number of bytes in result.
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for (auto byte : result)
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data[written++] = byte;
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}
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// 6.4.2. Otherwise, break.
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else {
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break;
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}
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++it;
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}
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// 7. Return «[ "read" → read, "written" → written ]».
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return { read, written };
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}
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// https://encoding.spec.whatwg.org/#dom-textencoder-encoding
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FlyString const& TextEncoder::encoding()
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{
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static FlyString const encoding = "utf-8"_fly_string;
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return encoding;
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}
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}
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