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43273fde27
For now, `BrotliDecode` hasn't been specified but it should be in a close future. So when it's possible we use the native `DecompressionStream` API with "brotli" as argument. If that fails or if we've to decompress in a sync context, we fallback to `BrotliStream` which a pure js implementation (see README in external/brotli).
87 lines
2.3 KiB
JavaScript
87 lines
2.3 KiB
JavaScript
/* Copyright 2026 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import { BrotliDecode } from "../../external/brotli/decode.js";
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import { DecodeStream } from "./decode_stream.js";
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import { Stream } from "./stream.js";
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class BrotliStream extends DecodeStream {
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#isAsync = true;
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constructor(stream, maybeLength) {
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super(maybeLength);
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this.stream = stream;
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this.dict = stream.dict;
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}
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readBlock() {
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// TODO: add some telemetry to measure how often we fallback here.
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// Get all bytes from the input stream
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const bytes = this.stream.getBytes();
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const decodedData = BrotliDecode(
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new Int8Array(bytes.buffer, bytes.byteOffset, bytes.length)
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);
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this.buffer = new Uint8Array(
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decodedData.buffer,
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decodedData.byteOffset,
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decodedData.length
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);
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this.bufferLength = this.buffer.length;
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this.eof = true;
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}
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async getImageData(length, _decoderOptions) {
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const data = await this.asyncGetBytes();
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if (!data) {
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return this.getBytes(length);
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}
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if (data.length <= length) {
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return data;
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}
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return data.subarray(0, length);
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}
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async asyncGetBytes() {
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const { decompressed, compressed } =
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await this.asyncGetBytesFromDecompressionStream("brotli");
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if (decompressed) {
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return decompressed;
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}
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// DecompressionStream failed (for example because there are some extra
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// bytes after the end of the compressed data), so we fallback to our
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// decoder.
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// We already get the bytes from the underlying stream, so we just reuse
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// them to avoid get them again.
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this.#isAsync = false;
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this.stream = new Stream(
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compressed,
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0,
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compressed.length,
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this.stream.dict
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);
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this.reset();
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return null;
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}
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get isAsync() {
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return this.#isAsync;
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}
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}
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export { BrotliStream };
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