Crate async_fd_lock

Advisory reader-writer locks for files.

Notes on Advisory Locks

“advisory locks” are locks which programs must opt-in to adhere to. This means that they can be used to coordinate file access, but not prevent access. Use this to coordinate file access between multiple instances of the same program. But do not use this to prevent actors from accessing or modifying files.

Example

use std::path::PathBuf;
use tokio::fs::File;
use tokio::io::{AsyncReadExt, AsyncWriteExt};
use async_fd_lock::{LockRead, LockWrite};

let dir = tempfile::tempdir().unwrap();
let path = dir.path().join("foo.txt");

// Lock it for writing.
{
    let mut write_guard = File::options()
        .create_new(true)
        .write(true)
        .truncate(true)
        .open(&path).await?
        .lock_write().await
        .map_err(|(_, err)| err)?;
    write_guard.write(b"bongo cat").await?;
}

// Lock it for reading.
{
    let mut read_guard_1 = File::open(&path).await?.lock_read().await.map_err(|(_, err)| err)?;
    let mut read_guard_2 = File::open(&path).await?.lock_read().await.map_err(|(_, err)| err)?;
    let byte_1 = read_guard_1.read_u8().await?;
    let byte_2 = read_guard_2.read_u8().await?;
}

Re-exports

• pub use nonblocking::*;

Modules

• blocking
• nonblocking

Structs

• RwLockReadGuard
  Onwed version of RwLockReadGuard
• RwLockWriteGuard
  Onwed version of RwLockWriteGuard

Traits

• AsOpenFile
  A trait to borrow the file descriptor from an underlying object.

Type Aliases

• LockReadResult
• LockWriteResult