Trait conch_runtime::spawn::Spawn

pub trait Spawn<E: ?Sized> {
    type EnvFuture: EnvFuture<E, Item = Self::Future, Error = Self::Error>;
    type Future: Future<Item = ExitStatus, Error = Self::Error>;
    type Error;
    fn spawn(self, env: &E) -> Self::EnvFuture;
}

A trait for spawning commands into an EnvFuture which can be polled to completion.

Spawning a command is separated into two distinct parts: a future that requires a mutable environment to make progress, and a future which no longer needs any context and can make progress on its own.

This distinction allows a caller to drop an environment as soon as it is no longer needed, which will free up resources, and especially important in preventing deadlocks between pipelines (since the parent process will contain extra reader/writer ends of a pipe and may prevent processes from exiting).

Associated Types

type EnvFuture: EnvFuture<E, Item = Self::Future, Error = Self::Error>

The future that represents spawning the command.

It represents all computations that may need an environment to progress further.

type Future: Future<Item = ExitStatus, Error = Self::Error>

The future that represents the exit status of a fully bootstrapped command, which no longer requires an environment to be driven to completion.

type Error

The type of error that a future will resolve with if it fails in a normal fashion.

Required Methods

fn spawn(self, env: &E) -> Self::EnvFuture

Spawn the command as a future.

Although the implementation is free to make any optimizations or pre-computations, there should be no observable side-effects until the very first call to poll on the future. That way a constructed future that was never polled could be dropped without the risk of unintended side effects.

Note: There are no guarantees that the environment will not change between the spawn invocation and the first call to poll() on the future. Thus any optimizations the implementation may decide to make based on the environment should be done with care.

Implementations on Foreign Types

impl<T: ?Sized, E: ?Sized> Spawn<E> for Rc<T> where
    T: 'static + SpawnBoxed<E>,
    E: 'static, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = T::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'b, T: ?Sized, E: ?Sized> Spawn<E> for &'b Rc<T> where
    T: 'static + SpawnBoxed<E>,
    E: 'static, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = T::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<T: ?Sized, E: ?Sized> Spawn<E> for Arc<T> where
    T: 'static + SpawnBoxed<E>,
    E: 'static, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = T::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'b, T: ?Sized, E: ?Sized> Spawn<E> for &'b Arc<T> where
    T: 'static + SpawnBoxed<E>,
    E: 'static, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = T::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<E: ?Sized, T> Spawn<E> for AndOrList<T> where
    E: LastStatusEnvironment + ReportErrorEnvironment,
    T: Spawn<E>,
    T::Error: IsFatalError, 

type Error = T::Error

type EnvFuture = AndOrList<T, IntoIter<AndOr<T>>, E>

type Future = ExitResult<T::Future>

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, E: ?Sized, T> Spawn<E> for &'a AndOrList<T> where
    E: LastStatusEnvironment + ReportErrorEnvironment,
    &'a T: Spawn<E>,
    <&'a T as Spawn<E>>::Error: IsFatalError, 

type Error = <&'a T as Spawn<E>>::Error

type EnvFuture = AndOrList<&'a T, AndOrRefIter<Iter<'a, AndOr<T>>>, E>

type Future = ExitResult<<&'a T as Spawn<E>>::Future>

fn spawn(self, env: &E) -> Self::EnvFuture

impl<E: ?Sized, T> Spawn<E> for Command<T> where
    E: LastStatusEnvironment,
    T: Spawn<E>,
    T::Error: From<RuntimeError>, 

type Error = T::Error

type EnvFuture = Command<T::EnvFuture>

type Future = T::Future

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, E: ?Sized, T> Spawn<E> for &'a Command<T> where
    E: LastStatusEnvironment,
    &'a T: Spawn<E>,
    <&'a T as Spawn<E>>::Error: From<RuntimeError>, 

type Error = <&'a T as Spawn<E>>::Error

type EnvFuture = Command<<&'a T as Spawn<E>>::EnvFuture>

type Future = <&'a T as Spawn<E>>::Future

fn spawn(self, env: &E) -> Self::EnvFuture

impl<S, R, E: ?Sized> Spawn<E> for CompoundCommand<S, R> where
    R: RedirectEval<E, Handle = E::FileHandle>,
    S: Spawn<E>,
    S::Error: From<RedirectionError> + From<R::Error>,
    E: AsyncIoEnvironment + FileDescEnvironment,
    E::FileHandle: Clone + From<FileDesc>, 

type EnvFuture = LocalRedirections<IntoIter<R>, S, E>

type Future = S::Future

type Error = S::Error

fn spawn(self, _env: &E) -> Self::EnvFuture

impl<'a, S, R, E: ?Sized> Spawn<E> for &'a CompoundCommand<S, R> where
    &'a R: RedirectEval<E, Handle = E::FileHandle>,
    &'a S: Spawn<E>,
    <&'a S as Spawn<E>>::Error: From<RedirectionError> + From<<&'a R as RedirectEval<E>>::Error>,
    E: AsyncIoEnvironment + FileDescEnvironment,
    E::FileHandle: Clone + From<FileDesc>, 

type EnvFuture = LocalRedirections<Iter<'a, R>, &'a S, E>

type Future = <&'a S as Spawn<E>>::Future

type Error = <&'a S as Spawn<E>>::Error

fn spawn(self, _env: &E) -> Self::EnvFuture

impl<T, W, S, E> Spawn<E> for CompoundCommandKind<T, W, S> where
    W: WordEval<E>,
    W::Error: IsFatalError,
    W::EvalResult: Into<E::Var>,
    S: 'static + Spawn<E> + SpawnBoxed<E, Error = <S as Spawn<E>>::Error>,
    <S as Spawn<E>>::Error: From<W::Error> + IsFatalError,
    E: 'static + ArgumentsEnvironment + LastStatusEnvironment + ReportErrorEnvironment + VariableEnvironment + SubEnvironment,
    E::Var: From<E::Arg>,
    E::VarName: Clone + From<T>, 

type EnvFuture = CompoundCommandKindFuture<IntoIter<S>, IntoIter<W>, IntoIter<GuardBodyPair<IntoIter<S>>>, IntoIter<PatternBodyPair<IntoIter<W>, IntoIter<S>>>, Arc<S>, E>

type Future = ExitResult<Either<S::Future, BoxStatusFuture<'static, Self::Error>>>

type Error = <S as Spawn<E>>::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, T, W, S, E> Spawn<E> for &'a CompoundCommandKind<T, W, S> where
    T: Clone,
    &'a W: WordEval<E>,
    <&'a W as WordEval<E>>::Error: IsFatalError,
    <&'a W as WordEval<E>>::EvalResult: Into<E::Var>,
    &'a S: Spawn<E>,
    <&'a S as Spawn<E>>::Error: IsFatalError,
    <&'a S as Spawn<E>>::Error: From<<&'a W as WordEval<E>>::Error> + IsFatalError,
    E: ArgumentsEnvironment + LastStatusEnvironment + ReportErrorEnvironment + VariableEnvironment + SubEnvironment,
    E::Var: From<E::Arg>,
    E::VarName: Clone + From<T>, 

type EnvFuture = CompoundCommandKindRefFuture<'a, S, W, E>

type Future = ExitResult<Either<<&'a S as Spawn<E>>::Future, <&'a S as Spawn<E>>::Future>>

type Error = <&'a S as Spawn<E>>::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<S, E> Spawn<E> for ListableCommand<S> where
    S: Spawn<E>,
    S::Error: From<Error>,
    E: FileDescEnvironment + SubEnvironment,
    E::FileHandle: From<FileDesc> + Clone, 

type EnvFuture = ListableCommand<S, E>

type Future = ExitResult<SpawnedPipeline<S, E>>

type Error = S::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, S: 'a, E> Spawn<E> for &'a ListableCommand<S> where
    &'a S: Spawn<E>,
    <&'a S as Spawn<E>>::Error: From<Error>,
    E: FileDescEnvironment + SubEnvironment,
    E::FileHandle: From<FileDesc> + Clone, 

type EnvFuture = ListableCommand<&'a S, E>

type Future = ExitResult<SpawnedPipeline<&'a S, E>>

type Error = <&'a S as Spawn<E>>::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<ERR, N, S, C, F, E: ?Sized> Spawn<E> for PipeableCommand<N, S, C, Rc<F>> where
    S: Spawn<E, Error = ERR>,
    C: Spawn<E, Error = ERR>,
    F: 'static + SpawnBoxed<E, Error = ERR>,
    E: FunctionEnvironment,
    E::FnName: From<N>,
    E::Fn: From<Rc<SpawnBoxed<E, Error = ERR> + 'static>>, 

type EnvFuture = PipeableCommand<N, S::EnvFuture, C::EnvFuture, Rc<SpawnBoxed<E, Error = ERR> + 'static>>

type Future = ExitResult<Either<S::Future, C::Future>>

type Error = ERR

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, ERR, N, S, C, F, E: ?Sized> Spawn<E> for &'a PipeableCommand<N, S, C, Rc<F>> where
    N: Clone,
    &'a S: Spawn<E, Error = ERR>,
    &'a C: Spawn<E, Error = ERR>,
    F: 'static + SpawnBoxed<E, Error = ERR>,
    E: FunctionEnvironment,
    E::FnName: From<N>,
    E::Fn: From<Rc<SpawnBoxed<E, Error = ERR> + 'static>>, 

type EnvFuture = PipeableCommand<N, <&'a S as Spawn<E>>::EnvFuture, <&'a C as Spawn<E>>::EnvFuture, Rc<SpawnBoxed<E, Error = ERR> + 'static>>

type Future = ExitResult<Either<<&'a S as Spawn<E>>::Future, <&'a C as Spawn<E>>::Future>>

type Error = ERR

fn spawn(self, env: &E) -> Self::EnvFuture

impl<ERR, N, S, C, F, E: ?Sized> Spawn<E> for PipeableCommand<N, S, C, Arc<F>> where
    S: Spawn<E, Error = ERR>,
    C: Spawn<E, Error = ERR>,
    F: 'static + SpawnBoxed<E, Error = ERR> + Send + Sync,
    E: FunctionEnvironment,
    E::FnName: From<N>,
    E::Fn: From<Arc<SpawnBoxed<E, Error = ERR> + Send + Sync + 'static>>, 

type EnvFuture = PipeableCommand<N, S::EnvFuture, C::EnvFuture, Arc<SpawnBoxed<E, Error = ERR> + Send + Sync + 'static>>

type Future = ExitResult<Either<S::Future, C::Future>>

type Error = ERR

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, ERR, N, S, C, F, E: ?Sized> Spawn<E> for &'a PipeableCommand<N, S, C, Arc<F>> where
    N: Clone,
    &'a S: Spawn<E, Error = ERR>,
    &'a C: Spawn<E, Error = ERR>,
    F: 'static + SpawnBoxed<E, Error = ERR> + Send + Sync,
    E: FunctionEnvironment,
    E::FnName: From<N>,
    E::Fn: From<Arc<SpawnBoxed<E, Error = ERR> + Send + Sync + 'static>>, 

type EnvFuture = PipeableCommand<N, <&'a S as Spawn<E>>::EnvFuture, <&'a C as Spawn<E>>::EnvFuture, Arc<SpawnBoxed<E, Error = ERR> + Send + Sync + 'static>>

type Future = ExitResult<Either<<&'a S as Spawn<E>>::Future, <&'a C as Spawn<E>>::Future>>

type Error = ERR

fn spawn(self, env: &E) -> Self::EnvFuture

impl<V, W, R, S, E: ?Sized> Spawn<E> for SimpleCommand<V, W, R> where
    R: RedirectEval<E, Handle = E::FileHandle>,
    R::Error: From<RedirectionError>,
    V: Hash + Eq + Borrow<String>,
    W: WordEval<E>,
    S: Clone + Spawn<E>,
    S::Error: From<CommandError> + From<RedirectionError> + From<R::Error> + From<W::Error>,
    E: AsyncIoEnvironment + ExecutableEnvironment + ExportedVariableEnvironment + FileDescEnvironment + FunctionEnvironment<Fn = S> + SetArgumentsEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Arg: From<W::EvalResult>,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<W::EvalResult>,
    E::VarName: Borrow<String> + Clone + From<V>,
    E::Var: Borrow<String> + Clone + From<W::EvalResult>, 

type EnvFuture = SimpleCommandEnvFuture<R, V, W, E>

type Future = ExitResult<SpawnedSimpleCommand<E::Future, S::Future>>

type Error = S::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, V, W, R, S, E: ?Sized> Spawn<E> for &'a SimpleCommand<V, W, R> where
    &'a R: RedirectEval<E, Handle = E::FileHandle>,
    <&'a R as RedirectEval<E>>::Error: From<RedirectionError>,
    V: Hash + Eq + Borrow<String> + Clone,
    &'a W: WordEval<E>,
    S: Clone + Spawn<E>,
    S::Error: From<CommandError> + From<RedirectionError> + From<<&'a R as RedirectEval<E>>::Error> + From<<&'a W as WordEval<E>>::Error>,
    E: AsyncIoEnvironment + ExecutableEnvironment + ExportedVariableEnvironment + FileDescEnvironment + FunctionEnvironment<Fn = S> + SetArgumentsEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Arg: From<<&'a W as WordEval<E>>::EvalResult>,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<<&'a W as WordEval<E>>::EvalResult>,
    E::VarName: Borrow<String> + Clone + From<V>,
    E::Var: Borrow<String> + Clone + From<<&'a W as WordEval<E>>::EvalResult>, 

type EnvFuture = SimpleCommandEnvFuture<&'a R, V, &'a W, E>

type Future = ExitResult<SpawnedSimpleCommand<E::Future, S::Future>>

type Error = S::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<T, E: ?Sized> Spawn<E> for TopLevelCommand<T> where
    T: 'static + StringWrapper + Display,
    E: 'static + AsyncIoEnvironment + ArgumentsEnvironment<Arg = T> + ExecutableEnvironment + ExportedVariableEnvironment<VarName = T, Var = T> + FileDescEnvironment + FunctionEnvironment + IsInteractiveEnvironment + LastStatusEnvironment + ReportErrorEnvironment + SetArgumentsEnvironment + SubEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<T>,
    E::Fn: Clone + From<Rc<SpawnBoxed<E, Error = RuntimeError> + 'static>> + Spawn<E, Error = RuntimeError>, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = RuntimeError

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, T: 'a, E: ?Sized> Spawn<E> for &'a TopLevelCommand<T> where
    T: 'static + StringWrapper + Display,
    E: 'static + AsyncIoEnvironment + ArgumentsEnvironment<Arg = T> + ExecutableEnvironment + ExportedVariableEnvironment<VarName = T, Var = T> + FileDescEnvironment + FunctionEnvironment + IsInteractiveEnvironment + LastStatusEnvironment + ReportErrorEnvironment + SetArgumentsEnvironment + SubEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<T>,
    E::Fn: Clone + From<Rc<SpawnBoxed<E, Error = RuntimeError> + 'static>> + Spawn<E, Error = RuntimeError>, 

type EnvFuture = BoxSpawnEnvFuture<'a, E, Self::Error>

type Future = BoxStatusFuture<'a, Self::Error>

type Error = RuntimeError

fn spawn(self, env: &E) -> Self::EnvFuture

impl<T, E: ?Sized> Spawn<E> for AtomicTopLevelCommand<T> where
    T: 'static + StringWrapper + Display + Send + Sync,
    E: 'static + AsyncIoEnvironment + ArgumentsEnvironment<Arg = T> + ExecutableEnvironment + ExportedVariableEnvironment<VarName = T, Var = T> + FileDescEnvironment + FunctionEnvironment + IsInteractiveEnvironment + LastStatusEnvironment + ReportErrorEnvironment + SetArgumentsEnvironment + SubEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<T>,
    E::Fn: Clone + From<Arc<SpawnBoxed<E, Error = RuntimeError> + Send + Sync + 'static>> + Spawn<E, Error = RuntimeError>, 

type EnvFuture = BoxSpawnEnvFuture<'static, E, Self::Error>

type Future = BoxStatusFuture<'static, Self::Error>

type Error = RuntimeError

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, T: 'a, E: ?Sized> Spawn<E> for &'a AtomicTopLevelCommand<T> where
    T: 'static + StringWrapper + Display + Send + Sync,
    E: 'static + AsyncIoEnvironment + ArgumentsEnvironment<Arg = T> + ExecutableEnvironment + ExportedVariableEnvironment<VarName = T, Var = T> + FileDescEnvironment + FunctionEnvironment + IsInteractiveEnvironment + LastStatusEnvironment + ReportErrorEnvironment + SetArgumentsEnvironment + SubEnvironment + UnsetVariableEnvironment + WorkingDirectoryEnvironment,
    E::Args: From<Vec<E::Arg>>,
    E::FileHandle: FileDescWrapper,
    E::FnName: From<T>,
    E::Fn: Clone + From<Arc<SpawnBoxed<E, Error = RuntimeError> + Send + Sync + 'static>> + Spawn<E, Error = RuntimeError>, 

type EnvFuture = BoxSpawnEnvFuture<'a, E, Self::Error>

type Future = BoxStatusFuture<'a, Self::Error>

type Error = RuntimeError

fn spawn(self, env: &E) -> Self::EnvFuture

impl<E: ?Sized, T: Spawn<E>> Spawn<E> for Box<T>

type EnvFuture = T::EnvFuture

type Future = T::Future

type Error = T::Error

fn spawn(self, env: &E) -> Self::EnvFuture

impl<'a, E: ?Sized, T: 'a> Spawn<E> for &'a Box<T> where
    &'a T: Spawn<E>, 

type EnvFuture = <&'a T as Spawn<E>>::EnvFuture

type Future = <&'a T as Spawn<E>>::Future

type Error = <&'a T as Spawn<E>>::Error

fn spawn(self, env: &E) -> Self::EnvFuture

Implementors

• impl<T, I, E: ?Sized> Spawn<E> for Cd<I> where
    T: StringWrapper,
    I: Iterator<Item = T>,
    E: AsyncIoEnvironment + ChangeWorkingDirectoryEnvironment + FileDescEnvironment + ReportErrorEnvironment + VariableEnvironment + WorkingDirectoryEnvironment,
    E::FileHandle: Borrow<FileDesc>,
    E::VarName: Borrow<String> + From<String>,
    E::Var: Borrow<String> + From<String>,  type EnvFuture = SpawnedCd<I>; type Future = ExitResult<CdFuture<E::WriteAll>>; type Error = Void;
• impl<E: ?Sized> Spawn<E> for Colon type EnvFuture = SpawnedColon; type Future = ExitStatus; type Error = Void;
• impl<T, I, E: ?Sized> Spawn<E> for Echo<I> where
    T: StringWrapper,
    I: Iterator<Item = T>,
    E: AsyncIoEnvironment,
    E: FileDescEnvironment,
    E: ReportErrorEnvironment,
    E::FileHandle: Borrow<FileDesc>,  type EnvFuture = SpawnedEcho<I>; type Future = ExitResult<EchoFuture<E::WriteAll>>; type Error = Void;
• impl<E: ?Sized> Spawn<E> for False type EnvFuture = SpawnedFalse; type Future = ExitStatus; type Error = Void;
• impl<T, I, E: ?Sized> Spawn<E> for Pwd<I> where
    T: StringWrapper,
    I: Iterator<Item = T>,
    E: AsyncIoEnvironment,
    E: FileDescEnvironment,
    E: ReportErrorEnvironment,
    E::FileHandle: Borrow<FileDesc>,
    E: WorkingDirectoryEnvironment,  type EnvFuture = SpawnedPwd<I>; type Future = ExitResult<PwdFuture<E::WriteAll>>; type Error = Void;
• impl<T, I, E: ?Sized> Spawn<E> for Shift<I> where
    T: StringWrapper,
    I: Iterator<Item = T>,
    E: ArgumentsEnvironment + ShiftArgumentsEnvironment + ReportErrorEnvironment,  type EnvFuture = SpawnedShift<I>; type Future = ExitStatus; type Error = Void;
• impl<E: ?Sized> Spawn<E> for True type EnvFuture = SpawnedTrue; type Future = ExitStatus; type Error = Void;