Parameter Closeable.CA

include Brassaia_eio_pack.Import.Brassaia.Indexable.S
include Brassaia_eio.Indexable_intf.S_without_key_impl

Read-only stores

Read-only stores are store where it is only possible to read existing values.

type -'a t

The type for stores. The 'a phantom type carries information about the store mutability.

type key

The type for keys.

type value

The type for raw values.

val mem : [> Brassaia_eio.Import.read ] t -> key -> bool

mem t k is true iff k is present in t.

val find : [> Brassaia_eio.Import.read ] t -> key -> value option

find t k is Some v if k is associated to v in t and None is k is not present in t.

val close : 'a t -> unit

close t frees up all the resources associated with t. Any operations run on a closed handle will raise Closed.

type hash

The type of hashes of value.

val index : [> Brassaia_eio.Import.read ] t -> hash -> key option

Indexing maps the hash of a value to a corresponding key of that value in the store. For stores that are addressed by hashes directly, this is typically fun _t h -> Lwt.return (Key.of_hash h); for stores with more complex addressing schemes, index may attempt a lookup operation in the store.

In general, indexing is best-effort and reveals no information about the membership of the value in the store. In particular:

  • index t hash = Some key doesn't guarantee mem t key: the value with hash hash may still be absent from the store;
  • index t hash = None doesn't guarantee that there is no key such that mem t key and Key.to_hash key = hash: the value may still be present in the store under a key that is not indexed.

batch t f applies the writes in f in a separate batch. The exact guarantees depend on the implementation.

module Key : Brassaia_eio.Key.S with type t = key and type hash = hash
val add : 'a t -> value -> key

Overwrite add to work with a read-only database handler.

val unsafe_add : 'a t -> hash -> value -> key

Overwrite unsafe_add to work with a read-only database handler.

val index_direct : _ t -> hash -> key option
val unsafe_append : ensure_unique:bool -> overcommit:bool -> 'a t -> hash -> value -> key
val unsafe_mem : 'a t -> key -> bool
val unsafe_find : check_integrity:bool -> 'a t -> key -> value option