bdrck 0.22.5

Generic common foundational utilities.
Documentation 
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
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92

// Copyright 2015 Axel Rasmussen
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

use crate::io::*;
use crate::testing::temp;
use std::fs;
use std::io::{self, Read};

#[test]
fn test_read_at_most() {
    crate::init().unwrap();

    let testdata = b"Hello, world!";
    for buffer_size in &[testdata.len() - 1, testdata.len(), testdata.len() + 1] {
        let tf = temp::File::new_file().unwrap();
        fs::write(tf.path(), testdata).unwrap();

        let mut f = fs::File::open(tf.path()).unwrap();
        let result = read_at_most(&mut f, *buffer_size);

        if *buffer_size < testdata.len() {
            assert!(result.is_err());
        } else {
            let data = result.unwrap();
            assert_eq!(testdata, data.as_slice());
        }
    }
}

/// A Read wrapper that returns Interrupted on its first N calls, then
/// delegates to the inner reader.
struct InterruptedReader<R: Read> {
    inner: R,
    remaining_interrupts: usize,
}

impl<R: Read> Read for InterruptedReader<R> {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        if self.remaining_interrupts > 0 {
            self.remaining_interrupts -= 1;
            return Err(io::Error::new(io::ErrorKind::Interrupted, "interrupt"));
        }
        self.inner.read(buf)
    }
}

#[test]
fn test_read_at_most_interrupted_retry() {
    crate::init().unwrap();

    let data: &[u8] = b"hello world";
    // Issue Interrupted twice before the main loop reads and once before the
    // EOF probe.
    let mut reader = InterruptedReader {
        inner: data,
        remaining_interrupts: 3,
    };

    let result = read_at_most(&mut reader, data.len()).unwrap();
    assert_eq!(data, result.as_slice());
}

#[test]
fn test_read_at_most_zero_buffer_with_data() {
    crate::init().unwrap();

    let data: &[u8] = b"not empty";
    let mut reader = data;
    // Asking for 0 bytes when there's data present should report InputTooBig.
    assert!(read_at_most(&mut reader, 0).is_err());
}

#[test]
fn test_read_at_most_zero_buffer_empty_input() {
    crate::init().unwrap();

    let data: &[u8] = b"";
    let mut reader = data;
    let result = read_at_most(&mut reader, 0).unwrap();
    assert!(result.is_empty());
}