// Copyright 2018-2022 System76 <info@system76.com>
// SPDX-License-Identifier: MIT OR Apache-2.0
use std::{
fs::File,
io::{self, BufRead, BufReader},
};
/// Data structure for validating if a filesystem argument is valid, and used within
/// automatic file system mounting.
#[derive(Clone, Debug)]
#[allow(clippy::module_name_repetitions)]
pub struct SupportedFilesystems {
nodev: Vec<bool>,
fs: Vec<String>,
}
impl SupportedFilesystems {
/// Detects available supported file systems on the system
///
/// # Errors
///
/// - On failure to open `/proc/filesystems`
pub fn new() -> io::Result<Self> {
let mut fss = Vec::with_capacity(64);
let mut nodevs = Vec::with_capacity(64);
for line in BufReader::new(File::open("/proc/filesystems")?).lines() {
let line = line?;
let mut line = line.split_whitespace();
let (nodev, fs) = match (line.next(), line.next()) {
(Some(fs), None) => (false, fs),
(Some("nodev"), Some(fs)) => (true, fs),
_ => continue,
};
nodevs.push(nodev);
fss.push(fs.to_owned());
}
Ok(SupportedFilesystems {
nodev: nodevs,
fs: fss,
})
}
/// Check if a provided file system is valid on this system.
///
/// ```rust
/// extern crate sys_mount;
///
/// use sys_mount::SupportedFilesystems;
///
/// fn main() {
/// let supports = SupportedFilesystems::new().unwrap();
/// println!("btrfs is {}", if supports.is_supported("btrfs") {
/// "supported"
/// } else {
/// "not supported"
/// });
/// }
/// ```
#[must_use]
pub fn is_supported(&self, fs: &str) -> bool {
self.fs.iter().any(|s| s.as_str() == fs)
}
/// Iterate through file systems which are not associated with physical devices.
#[must_use]
pub fn nodev_file_systems<'a>(&'a self) -> Box<dyn Iterator<Item = &str> + 'a> {
// TODO: When we can, switch to `impl Iterator`.
let iter = self.nodev.iter().enumerate().filter_map(move |(id, &x)| {
if x {
Some(self.fs[id].as_str())
} else {
None
}
});
Box::new(iter)
}
/// Iterate through file systems which are associated with physical devices.
#[must_use]
pub fn dev_file_systems<'a>(&'a self) -> Box<dyn Iterator<Item = &str> + 'a> {
// TODO: When we can, switch to `impl Iterator`.
let iter = self.nodev.iter().enumerate().filter_map(move |(id, &x)| {
if x {
None
} else {
Some(self.fs[id].as_str())
}
});
Box::new(iter)
}
}