Struct FileLock 

pub struct FileLock { /* private fields */ }

Exclusive file lock to prevent concurrent aria2 instances from writing to the same file simultaneously.

Uses platform-appropriate locking mechanism:

• On Unix: flock(LOCK_EX | LOCK_NB) via libc (non-blocking).
• On Windows: Creates a .lock marker file with exclusive semantics.
• On other platforms: No-op placeholder.

The lock is automatically released when this struct is dropped.

Implementations

impl FileLock

pub fn acquire(path: &Path) -> Result<Self, String>

Acquire an exclusive lock on the given file path.

Unix Behavior

Opens/creates the file and calls flock(fd, LOCK_EX | LOCK_NB). If another process already holds the lock, returns an error immediately (non-blocking). The lock is advisory – cooperative processes must all use flock for it to be effective. The lock is released when the returned FileLock is dropped (or when [release] is called).

Windows Behavior

Creates a sibling .lock file in the same directory. This is a simple marker-based approach; a production implementation would use LockFileEx or a named mutex for true exclusivity.

Errors

Returns Err if:

• The file cannot be created/opened (permission denied, disk full, etc.)
• Another process already holds the lock (Unix only)

pub fn release(self)

Explicitly release the lock.

After calling this method, the lock is released and the FileLock should no longer be used. Dropping the FileLock also releases the lock, so explicit release is optional.

pub fn is_held(&self) -> bool

Check whether we currently hold the lock.

Always returns true if [acquire] succeeded (the lock is held until dropped or explicitly released). Returns false only if the lock was never acquired.

pub fn path(&self) -> &Path

Return the path that this lock guards.

pub fn lock_file_path(&self) -> PathBuf

Return the actual platform-specific lock file path used for locking.

• Unix: Same as path() (the file itself is locked via flock).
• Windows: The .lock marker file (e.g., foo.lock for target foo).

Trait Implementations

impl Debug for FileLock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for FileLock

fn drop(&mut self)

Executes the destructor for this type.

fn pin_drop(self: Pin<&mut Self>)

🔬This is a nightly-only experimental API. (pin_ergonomics)

Execute the destructor for this type, but different to Drop::drop, it requires self to be pinned.