Context: switch to blake2B

Get rid of the old SHA1 that was used by git...

lib_crypto/base58.ml

@@ -301,6 +301,7 @@ module Prefix = struct
   let operation_list_hash = "\133\233" (* Lo(52) *)
   let operation_list_list_hash = "\029\159\109" (* LLo(53) *)
   let protocol_hash = "\002\170" (* P(51) *)
+  let context_hash = "\079\199" (* Co(52) *)
 
   (* 20 *)
   let ed25519_public_key_hash = "\006\161\159" (* tz1(36) *)

lib_crypto/base58.mli

@@ -16,6 +16,7 @@ module Prefix : sig
   val operation_list_hash: string
   val operation_list_list_hash: string
   val protocol_hash: string
+  val context_hash: string
   val ed25519_public_key_hash: string
   val cryptobox_public_key_hash: string
   val ed25519_public_key: string

lib_crypto/blake2B.ml

@@ -209,6 +209,11 @@ module Make (R : sig
         Data_encoding.(list (tup2 encoding arg_encoding))
   end
 
+  let zero =
+    match of_hex (String.make (size * 2) '0') with
+    | Some c -> c
+    | None -> assert false
+
 end
 
 module Generic_Merkle_tree (H : sig

lib_crypto/context_hash.ml

@@ -0,0 +1,18 @@
+(**************************************************************************)
+(*                                                                        *)
+(*    Copyright (c) 2014 - 2017.                                          *)
+(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
+(*                                                                        *)
+(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
+(*                                                                        *)
+(**************************************************************************)
+
+include Blake2B.Make (Base58) (struct
+    let name = "Context_hash"
+    let title = "A hash of context"
+    let b58check_prefix = Base58.Prefix.context_hash
+    let size = None
+  end)
+
+let () =
+  Base58.check_encoded_prefix b58check_encoding "Co" 52

lib_crypto/context_hash.mli

@@ -0,0 +1,10 @@
+(**************************************************************************)
+(*                                                                        *)
+(*    Copyright (c) 2014 - 2017.                                          *)
+(*    Dynamic Ledger Solutions, Inc. <contact@tezos.com>                  *)
+(*                                                                        *)
+(*    All rights reserved. No warranty, explicit or implicit, provided.   *)
+(*                                                                        *)
+(**************************************************************************)
+
+include S.INTERNAL_HASH

lib_crypto/net_id.ml

@@ -148,3 +148,8 @@ end
 
 let () =
   Base58.check_encoded_prefix b58check_encoding "Net" 15
+
+let zero =
+  match of_hex (String.make (size * 2) '0') with
+  | Some c -> c
+  | None -> assert false

lib_crypto/s.ml

@@ -94,6 +94,7 @@ module type INTERNAL_HASH = sig
     (t -> 'a, 'arg, 'ret) Cli_entries.params
   val random_set_elt: Set.t -> t
   module Table : Hashtbl.S with type key = t
+  val zero: t
 end
 
 module type INTERNAL_MERKLE_TREE = sig

lib_storage/context.ml

@@ -29,13 +29,49 @@ module Metadata = struct
   let merge = Irmin.Merge.default t
 end
 
+module IrminBlake2B : Irmin.Hash.S with type t = Context_hash.t = struct
+
+  type t = Context_hash.t
+
+  let digest_size = Context_hash.size
+
+  let to_raw t = Cstruct.of_bigarray (Context_hash.to_bytes t)
+  let of_raw t =
+    match Context_hash.of_bytes (Cstruct.to_bigarray t) with
+    | Some t -> t
+    | None ->
+        let str = Cstruct.to_string t in
+        Format.kasprintf invalid_arg "%s (%d)" str (String.length str)
+
+  let t = Irmin.Type.like Irmin.Type.cstruct of_raw to_raw
+
+  let digest t x =
+    Context_hash.hash_bytes
+      [Cstruct.to_bigarray (Irmin.Type.encode_cstruct t x)]
+
+  let pp = Context_hash.pp
+
+  let of_string x =
+    match Context_hash.of_b58check_exn x with
+    | exception (Invalid_argument s) -> Error (`Msg s)
+    | h -> Ok h
+
+  let has_kind = function
+    | `SHA1 -> true
+    | _ -> false
+
+  let to_raw_int c =
+    Int64.to_int @@ MBytes.get_int64 (Context_hash.to_bytes c) 0
+
+end
+
 module GitStore =
   Irmin_leveldb.Make
     (Metadata)
     (MBytesContent)
     (Irmin.Path.String_list)
     (Irmin.Branch.String)
-    (Irmin.Hash.SHA1)
+    (IrminBlake2B)
 
 type index = {
   path: string ;
@@ -50,30 +86,6 @@ and context = {
 }
 type t = context
 
-type commit = GitStore.Commit.Hash.t
-
-let dummy_commit =
-  match
-    GitStore.Commit.Hash.of_string "0000000000000000000000000000000000000000"
-  with
-  | Ok c -> c
-  | Error _ -> assert false
-
-let commit_encoding : commit Data_encoding.t =
-  let open Data_encoding in
-  conv
-    (fun c -> Cstruct.to_bigarray (Irmin.Type.encode_cstruct GitStore.Commit.Hash.t c))
-    (fun c ->
-       match
-         Irmin.Type.decode_cstruct
-           GitStore.Commit.Hash.t
-           (Cstruct.of_bigarray c)
-       with
-       | Ok x -> x
-       | _ -> assert false
-    )
-    bytes
-
 (*-- Version Access and Update -----------------------------------------------*)
 
 let current_protocol_key = ["protocol"]

lib_storage/context.mli

@@ -16,11 +16,6 @@ type index
 type t
 type context = t
 
-type commit
-
-val dummy_commit: commit
-val commit_encoding: commit Data_encoding.t
-
 (** Open or initialize a versioned store at a given path. *)
 val init:
   ?patch_context:(context -> context Lwt.t) ->
@@ -32,11 +27,11 @@ val commit_genesis:
   net_id:Net_id.t ->
   time:Time.t ->
   protocol:Protocol_hash.t ->
-  commit Lwt.t
+  Context_hash.t Lwt.t
 
 val commit_test_network_genesis:
   index -> Block_hash.t -> Time.t -> context ->
-  (Net_id.t * Block_hash.t * commit) tzresult Lwt.t
+  (Net_id.t * Block_hash.t * Context_hash.t) tzresult Lwt.t
 
 (** {2 Generic interface} ****************************************************)
 
@@ -61,16 +56,16 @@ val fold_keys:
 
 (** {2 Accessing and Updating Versions} **************************************)
 
-val exists: index -> commit -> bool Lwt.t
-val checkout: index -> commit -> context option Lwt.t
-val checkout_exn: index -> commit -> context Lwt.t
+val exists: index -> Context_hash.t -> bool Lwt.t
+val checkout: index -> Context_hash.t -> context option Lwt.t
+val checkout_exn: index -> Context_hash.t -> context Lwt.t
 val commit:
   time:Time.t ->
   message:string ->
   context ->
-  commit Lwt.t
-val set_head: index -> Net_id.t -> commit -> unit Lwt.t
-val set_master: index -> commit -> unit Lwt.t
+  Context_hash.t Lwt.t
+val set_head: index -> Net_id.t -> Context_hash.t -> unit Lwt.t
+val set_master: index -> Context_hash.t -> unit Lwt.t
 
 (** {2 Predefined Fields} ****************************************************)
 

lib_storage/store.ml

@@ -86,7 +86,7 @@ module Block = struct
     max_operations_ttl: int ;
     max_number_of_operations: int list;
     max_operation_data_length: int;
-    context: Context.commit ;
+    context: Context_hash.t ;
   }
 
   module Contents =
@@ -115,7 +115,7 @@ module Block = struct
                 (req "max_operations_ttl" uint16)
                 (req "max_number_of_operations" (list uint16))
                 (req "max_operation_data_length" uint16)
-                (req "context" Context.commit_encoding)
+                (req "context" Context_hash.encoding)
                 (req "header" Block_header.encoding))
        end))
 

lib_storage/store.mli

@@ -90,7 +90,7 @@ module Block : sig
     max_operations_ttl: int ;
     max_number_of_operations: int list;
     max_operation_data_length: int;
-    context: Context.commit ;
+    context: Context_hash.t ;
   }
 
   module Contents : SINGLE_STORE

test/shell/test_context.ml

@@ -84,10 +84,10 @@ let create_block3b idx block2_commit =
 
 type t = {
   idx: Context.index ;
-  genesis: Context.commit ;
-  block2: Context.commit ;
-  block3a: Context.commit ;
-  block3b: Context.commit ;
+  genesis: Context_hash.t ;
+  block2: Context_hash.t ;
+  block3a: Context_hash.t ;
+  block3b: Context_hash.t ;
 }
 
 let wrap_context_init f base_dir =

test/shell/test_store.ml

@@ -88,7 +88,7 @@ let lolblock ?(operations = []) header =
       } ;
     max_operations_ttl = 0 ;
     message = "" ;
-    context = Context.dummy_commit ;
+    context = Context_hash.zero ;
     max_number_of_operations = [] ;
     max_operation_data_length = 0 ;
   }