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use std::collections::HashMap;
use std::convert::From;
use std::fs::File;
use std::io::{BufReader, BufRead};
use std::path::Path;
const PATHS: [&'static str; 2] = ["/etc/os-release", "/usr/lib/os-release"];
const QUOTES: [&'static str; 2] = ["\"", "'"];
#[derive(Debug, PartialEq)]
pub enum OsReleaseError {
Io,
NoFile,
ParseError,
}
impl From<std::io::Error> for OsReleaseError {
fn from(_: std::io::Error) -> OsReleaseError {
OsReleaseError::Io
}
}
pub type Result<T> = std::result::Result<T, OsReleaseError>;
fn trim_quotes(s: &str) -> &str {
if QUOTES.iter().any(|q| s.starts_with(q) && s.ends_with(q)) {
&s[1..s.len() - 1]
} else {
s
}
}
fn extract_variable_and_value(s: &str) -> Result<(String, String)> {
if let Some(equal) = s.chars().position(|c| c == '=') {
let var = &s[..equal];
let val = &s[equal + 1..];
let val = trim_quotes(val.trim()).to_string();
Ok((var.trim().to_string(), val))
} else {
Err(OsReleaseError::ParseError)
}
}
pub fn parse_os_release<P: AsRef<Path>>(path: P) -> Result<HashMap<String, String>> {
let mut os_release = HashMap::new();
let file = try!(File::open(path));
let reader = BufReader::new(file);
for line in reader.lines() {
let line = try!(line);
let line = line.trim();
if line.starts_with('#') {
continue;
}
let var_val = try!(extract_variable_and_value(line));
os_release.insert(var_val.0, var_val.1);
}
Ok(os_release)
}
pub fn get_os_release() -> Result<HashMap<String, String>> {
for file in &PATHS {
if let Ok(os_release) = parse_os_release(file) {
return Ok(os_release);
}
}
Err(OsReleaseError::NoFile)
}