88 lines
1.6 KiB
JavaScript
88 lines
1.6 KiB
JavaScript
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export const streamChunk = function* (chunk, chunkSize) {
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let len = chunk.byteLength;
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if (!chunkSize || len < chunkSize) {
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yield chunk;
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return;
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}
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let pos = 0;
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let end;
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while (pos < len) {
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end = pos + chunkSize;
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yield chunk.slice(pos, end);
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pos = end;
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}
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}
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export const readBytes = async function* (iterable, chunkSize) {
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for await (const chunk of readStream(iterable)) {
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yield* streamChunk(chunk, chunkSize);
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}
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}
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const readStream = async function* (stream) {
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if (stream[Symbol.asyncIterator]) {
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yield* stream;
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return;
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}
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const reader = stream.getReader();
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try {
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for (;;) {
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const {done, value} = await reader.read();
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if (done) {
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break;
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}
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yield value;
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}
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} finally {
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await reader.cancel();
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}
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}
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export const trackStream = (stream, chunkSize, onProgress, onFinish) => {
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const iterator = readBytes(stream, chunkSize);
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let bytes = 0;
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let done;
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let _onFinish = (e) => {
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if (!done) {
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done = true;
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onFinish && onFinish(e);
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}
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}
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return new ReadableStream({
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async pull(controller) {
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try {
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const {done, value} = await iterator.next();
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if (done) {
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_onFinish();
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controller.close();
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return;
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}
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let len = value.byteLength;
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if (onProgress) {
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let loadedBytes = bytes += len;
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onProgress(loadedBytes);
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}
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controller.enqueue(new Uint8Array(value));
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} catch (err) {
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_onFinish(err);
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throw err;
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}
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},
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cancel(reason) {
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_onFinish(reason);
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return iterator.return();
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}
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}, {
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highWaterMark: 2
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})
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}
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