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|
extern crate libc;
use std::fs;
use std::io::Write;
#[derive(Debug, PartialEq)]
pub enum PidlockError {
LockExists,
InvalidState,
}
type PidlockResult = Result<(), PidlockError>;
#[derive(Debug, PartialEq)]
enum PidlockState {
New,
Acquired,
Released,
}
fn getpid() -> u32 {
unsafe { libc::getpid() as u32 }
}
pub struct Pidlock {
pid: u32,
path: String,
state: PidlockState,
}
impl Pidlock {
pub fn new(path: &str) -> Self {
Pidlock {
pid: getpid(),
path: path.to_string(),
state: PidlockState::New,
}
}
pub fn acquire(&mut self) -> PidlockResult {
match self.state {
PidlockState::New => {}
_ => {
return Err(PidlockError::InvalidState);
}
}
let mut file = match fs::OpenOptions::new()
.create_new(true)
.write(true)
.read(true)
.open(self.path.clone())
{
Ok(file) => file,
Err(_) => {
return Err(PidlockError::LockExists);
}
};
file.write(&format!("{}", self.pid).into_bytes()[..])
.unwrap();
self.state = PidlockState::Acquired;
Ok(())
}
pub fn release(&mut self) -> PidlockResult {
match self.state {
PidlockState::Acquired => {}
_ => {
return Err(PidlockError::InvalidState);
}
}
fs::remove_file(self.path.clone()).unwrap();
self.state = PidlockState::Released;
Ok(())
}
}
#[cfg(test)]
mod tests {
use super::{Pidlock, PidlockError};
use super::{getpid, PidlockState};
const TEST_PID: &str = "/tmp/test.pid";
#[test]
fn test_new() {
let pidfile = Pidlock::new(TEST_PID);
assert_eq!(pidfile.pid, getpid());
assert_eq!(pidfile.path, "/tmp/test.pid".to_string());
assert_eq!(pidfile.state, PidlockState::New);
}
#[test]
fn test_acquire_and_release() {
let mut pidfile = Pidlock::new(TEST_PID);
pidfile.acquire().unwrap();
assert_eq!(pidfile.state, PidlockState::Acquired);
pidfile.release().unwrap();
assert_eq!(pidfile.state, PidlockState::Released);
}
#[test]
fn test_acquire_lock_exists() {
let mut orig_pidfile = Pidlock::new(TEST_PID);
orig_pidfile.acquire().unwrap();
let mut pidfile = Pidlock::new(TEST_PID);
match pidfile.acquire() {
Err(err) => {
orig_pidfile.release().unwrap();
assert_eq!(err, PidlockError::LockExists);
}
_ => {
orig_pidfile.release().unwrap();
panic!("Test failed");
}
}
}
#[test]
fn test_acquire_already_acquired() {
let mut pidfile = Pidlock::new(TEST_PID);
pidfile.acquire().unwrap();
match pidfile.acquire() {
Err(err) => {
pidfile.release().unwrap();
assert_eq!(err, PidlockError::InvalidState);
}
_ => {
pidfile.release().unwrap();
panic!("Test failed");
}
}
}
#[test]
fn test_release_bad_state() {
let mut pidfile = Pidlock::new(TEST_PID);
match pidfile.release() {
Err(err) => {
assert_eq!(err, PidlockError::InvalidState);
}
_ => {
panic!("Test failed");
}
}
}
}
|
