Struct dir_lock::DirLock

#[must_use = "should call the drop_async method to unlock"]pub struct DirLock<'a>(_);

A simple file-system-based mutex.

When constructing a value of this type, a directory is created at the specified path. If a directory already exists, the constructor waits until it's removed. Dropping a DirLock removes the corresponding directory. Since creating a directory if it does not exist is an atomic operation on most operating systems, this can be used as a quick-and-dirty cross-process mutex.

To guard against processes exiting without properly removing the lock, a file containing the current process ID is created inside the lock. If no process with that ID exists, another process may claim the lock for itself.

Of course, this is still not completely fail-proof since the user or other processes could mess with the lock directory.

This type is a RAII lock guard, but unlocking a directory lock uses I/O and can error, so it is recommended to call drop_async.

Implementations

impl DirLock<'_>

pub async fn new(path: &impl AsRef<Path>) -> Result<DirLock<'_>, Error>

Acquires a directory lock at the given path, without blocking the thread.

See the type-level docs for details.

pub fn new_sync(path: &impl AsRef<Path>) -> Result<DirLock<'_>, Error>

Blocks the current thread until the lock can be established.

pub async fn drop_async(self) -> Result<(), Error>

Unlocks this lock without blocking the thread.

Trait Implementations

impl Drop for DirLock<'_>

pub fn drop(&mut self)

Unlocks this lock, blocking the current thread while doing so.

Panics

Unlocking a directory lock involves I/O. If an error occurs, this method will panic. It is recommended to use drop_async instead, which returns the error.