Struct Watchers

pub struct Watchers(/* private fields */);

Wraps all watcher connections observing one directory. The directory is responsible for calling Self::add() and Self::send_event() method when appropriate to make sure watchers are observing a consistent view.

Implementations

impl Watchers

pub fn new() -> Self

Constructs a new Watchers instance with no connected watchers.

pub fn add( &mut self, scope: ExecutionScope, directory: Arc<dyn Directory>, mask: WatchMask, watcher: DirectoryWatcher, ) -> Arc<Controller>

Connects a new watcher (connected over the channel) to the list of watchers. It is the responsibility of the caller to also send WATCH_EVENT_EXISTING and WatchMask::IDLE events on the returned Controller to the newly connected watcher using the Self::send_event methods. This mask is the event mask this watcher has requested.

Return value of None means the executor did not accept a new task, so the watcher has been dropped.

NOTE The reason add can not send both events on its own by consuming an EventProducer is because a lazy directory needs async context to generate a list of it’s entries. Meaning we need a async version of the EventProducer - and that is a lot of additional managing of functions and state. Traits do not support async methods yet, so we would need to manage futures returned by the EventProducer methods explicitly. Plus, for the crate::directory::immutable::Simple directory it is all unnecessary.

pub fn send_event(&mut self, producer: &mut dyn EventProducer)

Informs all the connected watchers about the specified event. While mask and event carry the same information, as they are represented by WatchMask::* and WATCH_EVENT_* constants in fuchsia.io, it is easier when both forms are provided. mask is used to filter out those watchers that did not request for observation of this event and event is used to construct the event object. The method will operate correctly only if mask and event match.

In case of a communication error with any of the watchers, connection to this watcher is closed.

pub fn remove(&mut self, key: usize)

Disconnects a watcher with the specified key. A directory will use this method during the unregister_watcher call.