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57 lines
1.6 KiB
TypeScript
57 lines
1.6 KiB
TypeScript
// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
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const { Buffer, mkdir, open } = Deno;
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type File = Deno.File;
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type Reader = Deno.Reader;
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import * as path from "../path/mod.ts";
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import { encode } from "../encoding/utf8.ts";
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/**
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* Copy bytes from one Uint8Array to another. Bytes from `src` which don't fit
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* into `dst` will not be copied.
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*
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* @param src Source byte array
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* @param dst Destination byte array
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* @param off Offset into `dst` at which to begin writing values from `src`.
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* @return number of bytes copied
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*/
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export function copyBytes(src: Uint8Array, dst: Uint8Array, off = 0): number {
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off = Math.max(0, Math.min(off, dst.byteLength));
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const dstBytesAvailable = dst.byteLength - off;
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if (src.byteLength > dstBytesAvailable) {
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src = src.subarray(0, dstBytesAvailable);
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}
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dst.set(src, off);
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return src.byteLength;
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}
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export function charCode(s: string): number {
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return s.charCodeAt(0);
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}
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export function stringsReader(s: string): Reader {
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return new Buffer(encode(s).buffer);
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}
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/** Create or open a temporal file at specified directory with prefix and
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* postfix
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* */
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export async function tempFile(
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dir: string,
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opts: {
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prefix?: string;
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postfix?: string;
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} = { prefix: "", postfix: "" }
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): Promise<{ file: File; filepath: string }> {
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const r = Math.floor(Math.random() * 1000000);
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const filepath = path.resolve(
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`${dir}/${opts.prefix || ""}${r}${opts.postfix || ""}`
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);
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await mkdir(path.dirname(filepath), { recursive: true });
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const file = await open(filepath, {
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create: true,
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read: true,
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write: true,
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append: true,
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});
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return { file, filepath };
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}
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