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https://github.com/denoland/deno.git
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f626b04ebe
Original: c5e6e015b5
61 lines
1.6 KiB
TypeScript
61 lines
1.6 KiB
TypeScript
// Ported to Deno from
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// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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import { Reader, ReadResult } from "deno";
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/** OneByteReader returns a Reader that implements
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* each non-empty Read by reading one byte from r.
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*/
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export class OneByteReader implements Reader {
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constructor(readonly r: Reader) {}
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async read(p: Uint8Array): Promise<ReadResult> {
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if (p.byteLength === 0) {
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return { nread: 0, eof: false };
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}
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if (!(p instanceof Uint8Array)) {
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throw Error("expected Uint8Array");
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}
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return this.r.read(p.subarray(0, 1));
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}
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}
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/** HalfReader returns a Reader that implements Read
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* by reading half as many requested bytes from r.
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*/
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export class HalfReader implements Reader {
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constructor(readonly r: Reader) {}
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async read(p: Uint8Array): Promise<ReadResult> {
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if (!(p instanceof Uint8Array)) {
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throw Error("expected Uint8Array");
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}
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const half = Math.floor((p.byteLength + 1) / 2);
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return this.r.read(p.subarray(0, half));
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}
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}
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export class ErrTimeout extends Error {
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constructor() {
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super("timeout");
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this.name = "ErrTimeout";
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}
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}
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/** TimeoutReader returns ErrTimeout on the second read
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* with no data. Subsequent calls to read succeed.
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*/
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export class TimeoutReader implements Reader {
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count = 0;
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constructor(readonly r: Reader) {}
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async read(p: Uint8Array): Promise<ReadResult> {
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this.count++;
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if (this.count === 2) {
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throw new ErrTimeout();
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}
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return this.r.read(p);
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}
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}
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