Source file `tezos_context_disk.ml`

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(*****************************************************************************)
(*                                                                           *)
(* Open Source License                                                       *)
(* Copyright (c) 2022-2022 Tarides <contact@tarides.com>                     *)
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(** Context comes with two variants: [Context] and [Context_binary] with
    different tradeoffs.

    Both have different Merkle tree representations (i.e. when presented the
    same data, they don't produce the same hashes).

    [lib_context] represents directories as a structured tree of inodes, instead
    of a flat list of files, to get efficient copy-on-write and optimised read
    patterns.

    The context variants differ by the branching factors used for these inode
    trees:

    - [Context] uses a branching factor of 32;
    - [Context_binary] uses a branching factor of 2.

    To represent a large directory, [Context] uses less but larger inodes than
    [Context_binary].

    As persisting inodes on disk have an overhead (i.e. the serialisation of an
    inode is prefixed by its 32 byte hash), [Context] is thus optimised for
    storing a large quantity of data on disk.

    On the opposite, as the inodes in Merkle proofs contain the hashes of the
    shallow siblings, [Context_binary] is thus optimised for producing smaller
    Merkle proofs. *)

module type TEZOS_CONTEXT_UNIX = Context.TEZOS_CONTEXT_UNIX

module Context_binary = Context.Make (Tezos_context_encoding.Context_binary)

(** The context of a tezos node. Persisted to disk. *)
module Context = Context.Make (Tezos_context_encoding.Context)