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use std::char;
use std::ffi::OsString;
use std::fs::File;
use std::io::{self, BufRead, BufReader, Error, ErrorKind};
use std::os::unix::ffi::OsStringExt;
use std::path::{Path, PathBuf};
use std::str::FromStr;
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
pub struct SwapInfo {
pub source: PathBuf,
pub kind: OsString,
pub size: usize,
pub used: usize,
pub priority: isize,
}
impl SwapInfo {
pub fn parse_line(line: &str) -> io::Result<SwapInfo> {
let mut parts = line.split_whitespace();
fn parse<F: FromStr>(string: &OsString) -> io::Result<F> {
let string = string.to_str().ok_or_else(|| Error::new(
ErrorKind::InvalidData,
"/proc/swaps contains non-UTF8 entry"
))?;
string.parse::<F>().map_err(|_| Error::new(
ErrorKind::InvalidData,
"/proc/swaps contains invalid data"
))
}
macro_rules! next_value {
($err:expr) => {{
parts.next()
.ok_or_else(|| Error::new(ErrorKind::Other, $err))
.and_then(|val| Self::parse_value(val))
}}
}
Ok(SwapInfo {
source: PathBuf::from(next_value!("Missing source")?),
kind: next_value!("Missing kind")?,
size: parse::<usize>(&next_value!("Missing size")?)?,
used: parse::<usize>(&next_value!("Missing used")?)?,
priority: parse::<isize>(&next_value!("Missing priority")?)?,
})
}
fn parse_value(value: &str) -> io::Result<OsString> {
let mut ret = Vec::new();
let mut bytes = value.bytes();
while let Some(b) = bytes.next() {
match b {
b'\\' => {
let mut code = 0;
for _i in 0..3 {
if let Some(b) = bytes.next() {
code *= 8;
code += u32::from_str_radix(&(b as char).to_string(), 8)
.map_err(|err| Error::new(ErrorKind::Other, err))?;
} else {
return Err(Error::new(ErrorKind::Other, "truncated octal code"));
}
}
ret.push(code as u8);
}
_ => {
ret.push(b);
}
}
}
Ok(OsString::from_vec(ret))
}
}
#[derive(Debug, Clone, Hash, Eq, PartialEq)]
pub struct SwapList(pub Vec<SwapInfo>);
impl SwapList {
pub fn parse_from<'a, I: Iterator<Item = &'a str>>(lines: I) -> io::Result<SwapList> {
lines.map(SwapInfo::parse_line)
.collect::<io::Result<Vec<SwapInfo>>>()
.map(SwapList)
}
pub fn new() -> io::Result<SwapList> {
Ok(SwapList(SwapIter::new()?.collect::<io::Result<Vec<SwapInfo>>>()?))
}
pub fn get_swapped(&self, path: &Path) -> bool {
self.0.iter().any(|mount| mount.source == path)
}
}
pub struct SwapIter {
file: BufReader<File>,
buffer: String
}
impl SwapIter {
pub fn new() -> io::Result<Self> {
let mut file = BufReader::new(File::open("/proc/swaps")?);
let mut buffer = String::with_capacity(512);
file.read_line(&mut buffer)?;
buffer.clear();
Ok(Self { file, buffer })
}
}
impl Iterator for SwapIter {
type Item = io::Result<SwapInfo>;
fn next(&mut self) -> Option<Self::Item> {
self.buffer.clear();
match self.file.read_line(&mut self.buffer) {
Ok(read) if read == 0 => None,
Ok(_) => Some(SwapInfo::parse_line(&self.buffer)),
Err(why) => Some(Err(why))
}
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::path::PathBuf;
use std::ffi::OsString;
const SAMPLE: &str = r#"Filename Type Size Used Priority
/dev/sda5 partition 8388600 0 -2"#;
#[test]
fn swaps() {
let swaps = SwapList::parse_from(SAMPLE.lines().skip(1)).unwrap();
assert_eq!(
swaps,
SwapList(vec![
SwapInfo {
source: PathBuf::from("/dev/sda5"),
kind: OsString::from("partition"),
size: 8_388_600,
used: 0,
priority: -2
}
])
);
assert!(swaps.get_swapped(Path::new("/dev/sda5")));
assert!(!swaps.get_swapped(Path::new("/dev/sda1")));
}
}