Stéphan Kochen
52 lines
1.3 KiB
TypeScript
52 lines
1.3 KiB
TypeScript
import type { Readable, Writable } from "stream";
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const MAX_UINT32 = 2 ** 32 - 1;
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/** Write one or more NAR strings to the output. */
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export const writeNarStrings = (out: Writable, ...input: string[]) => {
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let size = 0;
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const bufs = input.map((str) => {
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const buf = Buffer.from(str);
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// TODO: Support up to MAX_SAFE_INTEGER
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if (buf.byteLength > MAX_UINT32) {
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throw Error(`NAR string too long: ${buf.byteLength}`);
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}
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size += 8 + Math.ceil(buf.byteLength / 8) * 8;
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return buf;
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});
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const res = Buffer.alloc(size);
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let pos = 0;
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for (const buf of bufs) {
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res.writeUInt32LE(buf.byteLength, pos);
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buf.copy(res, pos + 8);
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pos += 8 + Math.ceil(buf.byteLength / 8) * 8;
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}
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out.write(res);
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};
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/** Write the contents of a stream as a NAR string to the output. */
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export const writeNarStream = async (
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out: Writable,
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size: number,
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input: Readable,
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) => {
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// TODO: Support up to MAX_SAFE_INTEGER
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if (size > MAX_UINT32) {
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throw Error(`NAR string too long: ${size}`);
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}
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const sizeBuf = Buffer.alloc(8);
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sizeBuf.writeUInt32LE(size);
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out.write(sizeBuf);
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for await (const chunk of input) {
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out.write(chunk);
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}
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const padding = 8 - (size % 8);
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if (padding !== 8) {
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out.write(Buffer.alloc(padding));
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}
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};
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