[−][src]Trait notify::Watcher

pub trait Watcher: Sized {
    fn new_immediate(tx: Sender<RawEvent>) -> Result<Self>;

    fn new(tx: Sender<Result<Event>>, delay: Duration) -> Result<Self>;

    fn watch<P: AsRef<Path>>(
        &mut self, 
        path: P, 
        recursive_mode: RecursiveMode
    ) -> Result<()>;

    fn unwatch<P: AsRef<Path>>(&mut self, path: P) -> Result<()>;

    fn configure(&mut self, _option: Config) -> Result<bool> { ... }
}

Type that can deliver file activity notifications

Watcher is implemented per platform using the best implementation available on that platform. In addition to such event driven implementations, a polling implementation is also provided that should work on any platform.

Required methods

fn new_immediate(tx: Sender<RawEvent>) -> Result<Self>

Create a new watcher in immediate mode.

Events will be sent using the provided tx immediately after they occur.

fn new(tx: Sender<Result<Event>>, delay: Duration) -> Result<Self>

Create a new debounced watcher with a delay.

Events won't be sent immediately; every iteration they will be collected, deduplicated, and emitted only after the specified delay.

Advantages

This has the advantage that a lot of logic can be offloaded to Notify.

For example you won't have to handle Modify(Name(From|To)) events yourself by piecing the two rename events together. Instead you will just receive a Modify(Name(Both)) with two paths from and to in that order.

Notify will also detect the beginning and the end of write operations. As soon as something is written to a file, a Modify notice is emitted. If no new event arrived until after the specified delay, a Modify event is emitted.

A practical example is "safe-saving", where a temporary file is created and written to, then only when everything has been written is it renamed to overwrite the file that was meant to be saved. Instead of receiving a Create event for the temporary file, Modify(Data) events to that file, and a Modify(Name) event from the temporary file to the file being saved, you will just receive a single Modify(Data) event.

If you use a delay of more than 30 seconds, you can avoid receiving repetitions of previous events on macOS.

Disadvantages

Your application might not feel as responsive.

If a file is saved very slowly, you might receive a Modify event even though the file is still being written to.

fn watch<P: AsRef<Path>>(
    &mut self,
    path: P,
    recursive_mode: RecursiveMode
) -> Result<()>

Begin watching a new path.

If the path is a directory, recursive_mode will be evaluated. If recursive_mode is RecursiveMode::Recursive events will be delivered for all files in that tree. Otherwise only the directory and its immediate children will be watched.

If the path is a file, recursive_mode will be ignored and events will be delivered only for the file.

On some platforms, if the path is renamed or removed while being watched, behaviour may be unexpected. See discussions in #165 and #166. If less surprising behaviour is wanted one may non-recursively watch the parent directory as well and manage related events.

fn unwatch<P: AsRef<Path>>(&mut self, path: P) -> Result<()>

Stop watching a path.

Errors

Returns an error in the case that path has not been watched or if removing the watch fails.

Loading content...

Provided methods

fn configure(&mut self, _option: Config) -> Result<bool>

Configure the watcher at runtime.

See the Config enum for all configuration options.

Returns

  • Ok(true) on success.
  • Ok(false) if the watcher does not support or implement the option.
  • Err(notify::Error) on failure.
Loading content...

Implementors

impl Watcher for INotifyWatcher[src]

impl Watcher for NullWatcher[src]

impl Watcher for PollWatcher[src]

Loading content...