Struct SubprocChain

pub struct SubprocChain { /* private fields */ }

An event source that processes a sequence of commands.

Exactly one event will ever be generated, and it will be either at the successful completion of all the commands OR at the first failed subprocess. If an optional cleanup command is provided, that will be run before the event is generated, but only in the event of a failure.

Note that to avoid leaking file descriptors (or the memory associated with the event source itself), you must either honour the calloop::PostAction returned from process_events() yourself, or use this with TransientSource in calloop.

Implementations

impl SubprocChain

pub fn new<T>(commands: T, cleanup: Option<Command>) -> Result<Self>

where T: IntoIterator<Item = Command>,

Create a new subprocess event source from a sequence of commands and, optionally, a cleanup command to run in case of failure.

Trait Implementations

impl EventSource for SubprocChain

fn process_events<F>( &mut self, readiness: Readiness, token: Token, callback: F, ) -> Result<PostAction, Self::Error>

where F: FnMut(Self::Event, &mut Self::Metadata) -> Self::Ret,

This event source is designed to fire exactly once, and the callback will receive the result. See the SubprocChain docs for more detail.

Even though the callback will only be called once, the API for calloop::EventSource requires it to be a FnMut. This can be worked around by wrapping a FnOnce in an Option type if necessary.

type Event = Result<(), ErrorEvent>

The type of events generated by your source.

type Metadata = ()

Some metadata of your event source

type Ret = ()

The return type of the user callback

type Error = LaunchError

The error type returned from process_events() (not the user callback!).

fn register( &mut self, poll: &mut Poll, token_factory: &mut TokenFactory, ) -> Result<()>

Register yourself to this poll instance

fn reregister( &mut self, poll: &mut Poll, token_factory: &mut TokenFactory, ) -> Result<()>

Re-register your file descriptors

fn unregister(&mut self, poll: &mut Poll) -> Result<()>

Unregister your file descriptors

fn pre_run<F>(&mut self, _callback: F) -> Result<(), Error>

where F: FnMut(Self::Event, &mut Self::Metadata) -> Self::Ret,

Notification that a polling session is going to start

fn post_run<F>(&mut self, _callback: F) -> Result<(), Error>

where F: FnMut(Self::Event, &mut Self::Metadata) -> Self::Ret,

Notification that the current polling session ended