0
0
Fork 0
mirror of https://github.com/denoland/deno.git synced 2024-10-30 09:08:00 -04:00
denoland-deno/std/io/iotest.ts
2019-10-09 17:10:09 -04:00

60 lines
1.5 KiB
TypeScript

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