Trait OwnedItem

Source

pub trait OwnedItem: Sized + Send {
    type Accepted: Send;
    type Rejection: Send;
    type Prerequisite: Send;

    // Provided method
    fn retain_accepted(_: Self::Accepted) -> Option<Self::Accepted> { ... }
}

Expand description

An action item interpreted as one whole owned input and an outside reply.

The interpreter borrows Option<Self> and its independent reply destination. It consumes the input only when it can preserve either the accepted value or the complete rejected, blocked or corrupt item in that destination. Dropping an interpretation future before consumption leaves the original input owned by the caller. Preparation and finalization use prepare_item and finish_item; they do not invoke an interpreter or move sibling items.

Implement ActionItem directly when interpretation needs a different custody or input equation. Implement this trait when the standard whole-item loan is the complete contract; the ActionItem implementation is supplied.

struct OpenFile { path: std::path::PathBuf }
impl behavior::OwnedItem for OpenFile {
    type Accepted = std::fs::File;
    type Rejection = std::io::Error;
    type Prerequisite = behavior::Never;

    fn retain_accepted(file: std::fs::File) -> Option<std::fs::File> {
        Some(file)
    }
}

The request can now be interpreted through InterpretItem without copying custody aliases or preparation/finalization. Its file remains owned during source settlement; ordinary receipts use the default discharge policy.