pub unsafe trait Storable: ToOwned {
type BytesRef<'a>: GenericCow<Borrowed = [u8]>
where
Self: 'a;
type AlignedRef<'a>: GenericCow<Borrowed = Self>;
const CONST_BYTES_LEN: bool;
const TRIVIAL_CMP: bool = false;
const OPTIMIZE_INT: bool = false;
fn to_bytes(&self) -> Self::BytesRef<'_>;
unsafe fn from_bytes_unchecked(bytes: &[u8]) -> Self::AlignedRef<'_>;
unsafe fn cmp_bytes_unchecked(a: &[u8], b: &[u8]) -> Ordering;
fn bytes_len(&self) -> usize { ... }
unsafe fn cmp_bytes_by_ord_unchecked(a: &[u8], b: &[u8]) -> Ordering
where
Self: Ord,
{ ... }
}Expand description
Types that can be stored
Any type that implements Storable can be used as a key or value in a
Db.
Implementation is unsafe and must be correct and not change between
(re-)opening environments.
Types that have a fixed-length byte representation should additionally
implement StorableConstBytesLen.
Several constants must be set correctly to enable various optimizations.
Required Associated Types
type BytesRef<'a>: GenericCow<Borrowed = [u8]>
where
Self: 'a
type BytesRef<'a>: GenericCow<Borrowed = [u8]>
where
Self: 'a
Byte representation as GenericCow
This can be a simple reference (&'a Self) or a
a smart-pointer (like Owned<[u8]>) which drops the byte
representation when the smart-pointer is dropped.
type AlignedRef<'a>: GenericCow<Borrowed = Self>
type AlignedRef<'a>: GenericCow<Borrowed = Self>
Aligned version of Self as GenericCow
This can be a simple reference (&'a Self) if there
are no requirements for memory alignment, or can be a smart-pointer
(like Owned<Self>) which drops the re-aligned copy when the
smart-pointer is dropped.
Required Associated Constants
const CONST_BYTES_LEN: bool
const CONST_BYTES_LEN: bool
Does byte representation have fixed length?
If this constant is true, then trait StorableConstBytesLen should
also be implemented.
Provided Associated Constants
const TRIVIAL_CMP: bool = false
const TRIVIAL_CMP: bool = false
Does Storable::cmp_bytes_unchecked perform a trivial (byte wise)
lexicographical comparison?
const OPTIMIZE_INT: bool = false
const OPTIMIZE_INT: bool = false
Required Methods
unsafe fn from_bytes_unchecked(bytes: &[u8]) -> Self::AlignedRef<'_>
unsafe fn from_bytes_unchecked(bytes: &[u8]) -> Self::AlignedRef<'_>
Converts from byte slice
unsafe fn cmp_bytes_unchecked(a: &[u8], b: &[u8]) -> Ordering
unsafe fn cmp_bytes_unchecked(a: &[u8], b: &[u8]) -> Ordering
Compares byte representation
Provided Methods
Compares byte representation using Ord
This function is provided for convenient implementation of
Storable::cmp_bytes_unchecked where desired.