irmin-pack

Irmin backend which stores values in a pack file
IN THIS PACKAGE

Parameters

module H : Irmin.Hash.S
module Pack : Pack_store.S with type hash = H.t and type key = H.t Irmin_pack.Pack_key.t and type value = Inter.Raw.t

Signature

include Irmin_pack.Inode.S with type key = H.t Irmin_pack.Pack_key.t with type hash = H.t with type Val.metadata = Node.metadata with type Val.step = Node.step with type value = Inter.Val.t
include Irmin.Indexable.S with type key = H.t Irmin_pack.Pack_key.t with type hash = H.t with type value = Inter.Val.t

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.

The type for keys.

type value = Inter.Val.t

The type for raw values.

val mem : [> Irmin.Perms.read ] t -> key -> bool Lwt.t

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

val find : [> Irmin.Perms.read ] t -> key -> value option Lwt.t

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 Lwt.t

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

type hash = H.t

The type of hashes of value.

val add : [> Irmin.Perms.write ] t -> value -> key Lwt.t

Write the contents of a value to the store, and obtain its key.

val unsafe_add : [> Irmin.Perms.write ] t -> hash -> value -> key Lwt.t

Same as add but allows specifying the value's hash directly. The backend might choose to discard that hash and/or can be corrupt if the hash is not consistent.

val index : [> Irmin.Perms.read ] t -> hash -> key option Lwt.t

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.
val batch : Irmin.Perms.read t -> ( [ Irmin.Perms.read | Irmin.Perms.write ] t -> 'a Lwt.t ) -> 'a Lwt.t

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

module Key : Irmin.Key.S with type t = key and type hash = hash
module Hash : Irmin.Hash.S with type t = hash

Signature for digest hashes, inspired by Digestif.

module Val : sig ... end
val decode_bin_length : string -> int -> int
val save : ?allow_non_root:bool -> 'a t -> value -> key
type file_manager = Pack.file_manager
type dict = Pack.dict
include Irmin_pack.S.Checkable with type 'a t := 'a t and type hash := hash
val integrity_check : offset:Optint.Int63.t -> length:int -> hash -> _ t -> ( unit, [ `Wrong_hash | `Absent_value ] ) result
val integrity_check_inodes : [ `Read ] t -> key -> ( unit, string ) result Lwt.t
module Pack : Pack_store.S with type file_manager = file_manager and type dict = dict and type key := hash Irmin_pack.Pack_key.t and type hash := hash and type 'a t = 'a t
module Raw : Irmin_pack.Inode.Raw with type t = Pack.value and type hash := hash and type key := hash Irmin_pack.Pack_key.t
val to_snapshot : Raw.t -> Snapshot.inode
val of_snapshot : 'a t -> index:( hash -> key ) -> Snapshot.inode -> value