blob: d4365526362a475a03c1056211deb9d171e422e7 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
|
// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
// Based on https://github.com/golang/go/blob/0452f9460f50f0f0aba18df43dc2b31906fb66cc/src/io/io.go
// 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;
import { encode } from "../encoding/utf8.ts";
const { Buffer } = Deno;
/** Reader utility for strings */
export class StringReader extends Buffer {
constructor(private readonly s: string) {
super(encode(s).buffer);
}
}
/** Reader utility for combining multiple readers */
export class MultiReader implements Reader {
private readonly readers: Reader[];
private currentIndex = 0;
constructor(...readers: Reader[]) {
this.readers = readers;
}
async read(p: Uint8Array): Promise<number | null> {
const r = this.readers[this.currentIndex];
if (!r) return null;
const result = await r.read(p);
if (result === null) {
this.currentIndex++;
return 0;
}
return result;
}
}
/**
* A `LimitedReader` reads from `reader` but limits the amount of data returned to just `limit` bytes.
* Each call to `read` updates `limit` to reflect the new amount remaining.
* `read` returns `null` when `limit` <= `0` or
* when the underlying `reader` returns `null`.
*/
export class LimitedReader implements Deno.Reader {
constructor(public reader: Deno.Reader, public limit: number) {}
async read(p: Uint8Array): Promise<number | null> {
if (this.limit <= 0) {
return null;
}
if (p.length > this.limit) {
p = p.subarray(0, this.limit);
}
const n = await this.reader.read(p);
if (n == null) {
return null;
}
this.limit -= n;
return n;
}
}
|
