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denoland-deno/iotest.ts
Ryan Dahl 9b014313db Add bufio tests.
Original: aa9e3df0d2
2018-11-07 20:28:01 -05:00

61 lines
1.6 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.
import { Reader, ReadResult } from "deno";
/** 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: ArrayBufferView): Promise<ReadResult> {
if (p.byteLength === 0) {
return { nread: 0, eof: false };
}
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: ArrayBufferView): Promise<ReadResult> {
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: ArrayBufferView): Promise<ReadResult> {
this.count++;
if (this.count === 2) {
throw new ErrTimeout();
}
return this.r.read(p);
}
}