pub trait Owned<'a> {
type Reader: FromPointerReader<'a> + SetPointerBuilder<Self::Builder>;
type Builder: FromPointerBuilder<'a>;
}
Expand description
Associated types hackery that allows us to reason about Cap’n Proto types
without needing to give them a lifetime 'a
.
If Foo
is a Cap’n Proto struct and Bar
is a Rust-native struct, then
foo::Reader<'a>
is to foo::Owned
as &'a Bar
is to Bar
, and
foo::Builder<'a>
is to foo::Owned
as &'a mut Bar
is to Bar
.
The relationship is formalized by an impl <'a> capnp::traits::Owned<'a> for foo::Owned
.
Because Cap’n Proto struct layout differs from Rust struct layout, a foo::Owned
value
cannot be used for anything interesting on its own; the foo::Owned
type is useful
nonetheless as a type parameter, e.g. for a generic container that owns a Cap’n Proto
message of type T: for<'a> capnp::traits::Owned<'a>
.