package tezos-context

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Tezos: on-disk context abstraction for `octez-node`

Install 

dune-project
 Dependency

www.tezos.com Readme Edit opam file Versions (5)

Authors

  1. T
    Tezos devteam

Maintainers

  1. C
    contact@tezos.com

Sources

tezos-17.3.tar.gz
sha256=7062cd57addd452852598a2214ade393130efa087b99068d53713bdf912b3680
sha512=08e4091144a03ce3c107fb91a66501bd8b65ca3278917c455a2eaac6df3e108ade63f6ab8340a4bb152d60f404326e464d0ec95d26cafe8e82f870465d24a5fc

doc/tezos-context.helpers/Tezos_context_helpers/Context/Make_tree/argument-2-DB/Backend/Node/index.html

Module Backend.Node

A node store.

include Irmin.Indexable.S with type hash = Hash.t with type key = node_key

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 = node_key

The type for keys.

type value

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 = Hash.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 Path = Path

Path provides base functions on node paths.

val merge : [> Irmin.Perms.read_write ] t -> key option Irmin.Merge.t

merge is the 3-way merge function for nodes keys.

module Metadata = Schema.Metadata

Metadata provides base functions for node metadata.

module Val : sig ... end

Val provides base functions for node values.

module Hash : Irmin.Hash.Typed with type t = hash and type value = value

Contents is the underlying contents store.