OwningHandle
is a complement to OwningRef
. Where OwningRef
allows
consumers to pass around an owned object and a dependent reference,
OwningHandle
contains an owned object and a dependent object.
OwningHandle
can encapsulate a RefMut
along with its associated
RefCell
, or an RwLockReadGuard
along with its associated RwLock
.
However, the API is completely generic and there are no restrictions on
what types of owning and dependent objects may be used.
OwningHandle
is created by passing an owner object (which dereferences
to a stable address) along with a callback which receives a pointer to
that stable location. The callback may then dereference the pointer and
mint a dependent object, with the guarantee that the returned object will
not outlive the referent of the pointer.
Since the callback needs to dereference a raw pointer, it requires unsafe
code. To avoid forcing this unsafety on most callers, the ToHandle
trait is
implemented for common data structures. Types that implement ToHandle
can
be wrapped into an OwningHandle
without passing a callback.
Create a new OwningHandle
for a type that implements ToHandle
. For types
that don't implement ToHandle
, callers may invoke new_with_fn
, which accepts
a callback to perform the conversion.
Create a new mutable OwningHandle
for a type that implements ToHandleMut
.
Create a new OwningHandle. The provided callback will be invoked with
a pointer to the object owned by o
, and the returned value is stored
as the object to which this OwningHandle
will forward Deref
and
DerefMut
.
Create a new OwningHandle. The provided callback will be invoked with
a pointer to the object owned by o
, and the returned value is stored
as the object to which this OwningHandle
will forward Deref
and
DerefMut
.
Mutably dereferences the value.
The resulting type after dereferencing.
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
type Error = <U as TryFrom<T>>::Error
🔬 This is a nightly-only experimental API. (try_from
)
The type returned in the event of a conversion error.
🔬 This is a nightly-only experimental API. (try_from
)
🔬 This is a nightly-only experimental API. (get_type_id
)
this method will likely be replaced by an associated static
Create an error for a missing method specialization. Defaults to panicking with type, trait & method names. S
is the encoder/decoder state type, T
is the type being encoded/decoded, and the arguments are the names of the trait and method that should've been overridden. Read more