[−][src]Module fastobo::share

Enhanced Borrow, ToOwned and Cow to use in tree structures.

This module define two traits:

  • Share, related to std::borrow::Borrow
  • Redeem, related to std::borrow::ToOwned as well as the Cow enum with an interface close to std::borrow::Cow.

The main differences with traits from std::borrow are that:

  • Share::share does not need to return a reference.
  • Share::share has access to the lifetime of the referenced owner.
  • Redeem<Owned=T> for B does not require impl Share<B> for T
  • Cow supports owning structures (preferably Shared ones).
  • Cow needs explicit references where applicable (e.g. Cow<'a, &'a str>).

This allow a Cow-like behaviour on enum structures referencing pointers.

Examples

use fastobo::share::{Cow, Redeem, Share};

pub struct MyOwner(String);

#[derive(Clone)]
pub struct MyRef<'a>(Cow<'a, &'a str>);

impl<'a> Share<'a, MyRef<'a>> for MyOwner {
    fn share(&'a self) -> MyRef<'a> {
        MyRef(Cow::from(self.0.as_ref()))
    }
}

impl<'a> Redeem<'a> for MyRef<'a> {
    type Owned = MyOwner;
    fn redeem(&'a self) -> Self::Owned {
        MyOwner(self.0.to_string())
    }
}

Enums

Cow

Traits

Redeem

A trait for taking ownership over viewed data with possibly expensives costs.

Share

A trait for obtaining a data view from a reference to an owned struct.