mmoxi 0.3.1

spectrum scale tools
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
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

//! `mmlsfs` parsing.

use std::io::BufRead;
use std::process::Command;

use anyhow::{anyhow, Context, Result};

/// Returns the file system names.
///
/// # Errors
///
/// Returns an error if running `mmlsfs` fails or if parsing its output fails.
pub fn names() -> Result<Vec<String>> {
    let mut cmd = Command::new("mmlsfs");
    cmd.args(["all", "-Y", "-B"]);

    let output = cmd
        .output()
        .with_context(|| format!("error running: {cmd:?}"))?;

    let data = Filesystems::from_reader(output.stdout.as_slice())?;

    let names = data.0.into_iter().map(|fs| fs.name).collect();

    Ok(names)
}

/// Parsed file systems.
#[derive(Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug, Default)]
pub struct Filesystems(Vec<Filesystem>);

impl Filesystems {
    fn from_reader<Input: BufRead>(input: Input) -> Result<Self> {
        let mut index = Index::default();
        let mut fs = Self::default();

        for line in input.lines() {
            let line = line?;

            let tokens = line.split(':').collect::<Vec<_>>();

            if tokens[2] == "HEADER" {
                index = Index::default();
                header_to_index(&tokens, &mut index);
            } else {
                let entry = Filesystem::from_tokens(&tokens, &index)?;
                fs.0.push(entry);
            }
        }

        Ok(fs)
    }
}

impl IntoIterator for Filesystems {
    type Item = Filesystem;
    type IntoIter = std::vec::IntoIter<Self::Item>;

    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}

/// File system data.
#[derive(Clone, Eq, PartialEq, Ord, PartialOrd, Hash, Debug)]
pub struct Filesystem {
    name: String,
}

impl Filesystem {
    /// Returns the file system name.
    #[must_use]
    pub fn name(&self) -> &str {
        &self.name
    }
}

// ----------------------------------------------------------------------------
// boiler-platy parsing
// ----------------------------------------------------------------------------

impl Filesystem {
    fn from_tokens(tokens: &[&str], index: &Index) -> Result<Self> {
        let name_index = index
            .name
            .ok_or_else(|| anyhow!("no filesystem name index"))?;
        let name = tokens[name_index].into();

        Ok(Self { name })
    }
}

#[derive(Debug, Default)]
struct Index {
    name: Option<usize>,
}

fn header_to_index(tokens: &[&str], index: &mut Index) {
    for (i, token) in tokens.iter().enumerate() {
        if *token == "deviceName" {
            index.name = Some(i);
        }
    }
}

// ----------------------------------------------------------------------------
// tests
// ----------------------------------------------------------------------------

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn parse() {
        let input = include_str!("fs-example.in");

        let fs = Filesystems::from_reader(input.as_bytes()).unwrap();
        let mut fs = fs.0.into_iter();

        assert_eq!(
            fs.next(),
            Some(Filesystem {
                name: "gpfs1".into()
            })
        );

        assert_eq!(
            fs.next(),
            Some(Filesystem {
                name: "gpfs2".into()
            })
        );

        assert_eq!(fs.next(), None);
    }
}