Revision 322c73366a9198d5bd6be08e91b729c775761821 authored by Diane Gallois-Wong on 31 August 2022, 15:57:02 UTC, committed by Marge Bot on 06 September 2022, 08:21:04 UTC
Notably, remove plugin tests on 1M, since the plugin is no longer responsible for enforcing 1M. Similar tests on 1M already exist in tezt, and will be extended in the next commit to cover all the cases of the removed tests.
1 parent 995112f
merkle_list.ml
(*****************************************************************************)
(* *)
(* Open Source License *)
(* Copyright (c) 2022 Nomadic Labs <contact@nomadic-labs.com> *)
(* *)
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(* copy of this software and associated documentation files (the "Software"),*)
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(* Software is furnished to do so, subject to the following conditions: *)
(* *)
(* The above copyright notice and this permission notice shall be included *)
(* in all copies or substantial portions of the Software. *)
(* *)
(* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR*)
(* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, *)
(* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL *)
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(* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING *)
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(*****************************************************************************)
type error += Merkle_list_invalid_position
let max_depth ~count_limit =
(* We assume that the Merkle_tree implemenation computes a tree in a
logarithmic size of the number of leaves. *)
let log2 n = Z.numbits (Z.of_int n) in
log2 count_limit
let _ =
register_error_kind
`Temporary
~id:"Merkle_list_invalid_position"
~title:"Merkle_list_invalid_position"
~description:"Merkle_list_invalid_position"
~pp:(fun ppf () -> Format.fprintf ppf "%s" "Merkle_list_invalid_position")
Data_encoding.empty
(function Merkle_list_invalid_position -> Some () | _ -> None)
(fun () -> Merkle_list_invalid_position)
module type T = sig
type t
type h
type elt
type path
val dummy_path : path
val pp_path : Format.formatter -> path -> unit
val nil : t
val empty : h
val root : t -> h
val snoc : t -> elt -> t
val snoc_tr : t -> elt -> t
val compute : elt list -> h
val path_encoding : path Data_encoding.t
val bounded_path_encoding : ?max_length:int -> unit -> path Data_encoding.t
val compute_path : t -> int -> path tzresult
val check_path : path -> int -> elt -> h -> bool tzresult
val path_depth : path -> int
val elt_bytes : elt -> Bytes.t
module Internal_for_tests : sig
val path_to_list : path -> h list
val equal : t -> t -> bool
val to_list : t -> h list
end
end
module Make (El : sig
type t
val to_bytes : t -> bytes
end)
(H : S.HASH) : T with type elt = El.t and type h = H.t = struct
type h = H.t
type elt = El.t
let elt_bytes = El.to_bytes
(*
The goal of this structure is to model an append-only list.
Its internal representation is that of a binary tree whose
leaves are all at the same level (the tree's height).
To insert a new element in a full tree t, we create a new root with t
as its left subtree and a new tree t' as its right subtree. t' is just a
left-spine of the same height as t. Visually,
t = / \ t' = / snoc 4 t = / \
/\ /\ / / \ /
0 1 2 3 4 /\ /\ /
0 1 2 3 4
Then, this is a balanced tree by construction.
As the key in the tree for a given position is the position's
binary decomposition of size height(tree), the tree is dense.
For that reason, the use of extenders is not needed.
*)
type tree = Empty | Leaf of h | Node of (h * tree * tree)
(* The tree has the following invariants:
A node [Node left right] if valid iff
1. [right] is Empty and [left] is not Empty, or
2. [right] is not Empty and [left] is full
Additionally:
[t.depth] is the height of [t.tree] and
[t.next_pos] is the number of leaves in [t.tree] *)
type t = {tree : tree; depth : int; next_pos : int}
type path = h list
let dummy_path = []
let pp_path ppf =
Format.fprintf
ppf
"%a"
(Format.pp_print_list
~pp_sep:(fun fmt () -> Format.fprintf fmt ";@ ")
H.pp)
let empty = H.zero
let root = function Empty -> empty | Leaf h -> h | Node (h, _, _) -> h
let nil = {tree = Empty; depth = 0; next_pos = 0}
let hash_elt el = H.hash_bytes [elt_bytes el]
let leaf_of el = Leaf (hash_elt el)
let hash2 h1 h2 = H.(hash_bytes [to_bytes h1; to_bytes h2])
let node_of t1 t2 = Node (hash2 (root t1) (root t2), t1, t2)
(* to_bin computes the [depth]-long binary representation of [pos]
(left-padding with 0s if required). This corresponds to the tree traversal
of en element at position [pos] (false = left, true = right).
Pre-condition: pos >= 0 /| pos < 2^depth
Post-condition: len(to_bin pos depth) = depth *)
let to_bin ~pos ~depth =
let rec aux acc pos depth =
let (pos', dir) = (pos / 2, pos mod 2) in
match depth with
| 0 -> acc
| d -> aux (Compare.Int.(dir = 1) :: acc) pos' (d - 1)
in
aux [] pos depth
(* Constructs a tree of a given depth in which every right subtree is empty
* and the only leaf contains the hash of el. *)
let make_spine_with el =
let rec aux left = function
| 0 -> left
| d -> (aux [@tailcall]) (node_of left Empty) (d - 1)
in
aux (leaf_of el)
let snoc t (el : elt) =
let rec traverse tree depth key =
match (tree, key) with
| (Node (_, t_left, Empty), true :: _key) ->
(* The base case where the left subtree is full and we start
* the right subtree by creating a new tree the size of the remaining
* depth and placing the new element in its leftmost position. *)
let t_right = make_spine_with el (depth - 1) in
node_of t_left t_right
| (Node (_, t_left, Empty), false :: key) ->
(* Traversing left, the left subtree is not full (and thus the right
* subtree is empty). Recurse on left subtree. *)
let t_left = traverse t_left (depth - 1) key in
node_of t_left Empty
| (Node (_, t_left, t_right), true :: key) ->
(* Traversing right, the left subtree is full.
* Recurse on right subtree *)
let t_right = traverse t_right (depth - 1) key in
node_of t_left t_right
| (_, _) ->
(* Impossible by construction of the tree and of the key.
* See [tree] invariants and [to_bin]. *)
assert false
in
let (tree', depth') =
match (t.tree, t.depth, t.next_pos) with
| (Empty, 0, 0) -> (node_of (leaf_of el) Empty, 1)
| (tree, depth, pos) when Int32.(equal (shift_left 1l depth) (of_int pos))
->
let t_right = make_spine_with el depth in
(node_of tree t_right, depth + 1)
| (tree, depth, pos) ->
let key = to_bin ~pos ~depth in
(traverse tree depth key, depth)
in
{tree = tree'; depth = depth'; next_pos = t.next_pos + 1}
type zipper = Left of zipper * tree | Right of tree * zipper | Top
let rec rebuild_tree z t =
match z with
| Top -> t
| Left (z, r) -> (rebuild_tree [@tailcall]) z (node_of t r)
| Right (l, z) -> (rebuild_tree [@tailcall]) z (node_of l t)
let snoc_tr t (el : elt) =
let rec traverse (z : zipper) tree depth key =
match (tree, key) with
| (Node (_, t_left, Empty), true :: _key) ->
let t_right = make_spine_with el (depth - 1) in
rebuild_tree z (node_of t_left t_right)
| (Node (_, t_left, Empty), false :: key) ->
let z = Left (z, Empty) in
(traverse [@tailcall]) z t_left (depth - 1) key
| (Node (_, t_left, t_right), true :: key) ->
let z = Right (t_left, z) in
(traverse [@tailcall]) z t_right (depth - 1) key
| (_, _) ->
(* Impossible by construction of the tree and of the key.
* See [tree] invariants and [to_bin]. *)
assert false
in
let (tree', depth') =
match (t.tree, t.depth, t.next_pos) with
| (Empty, 0, 0) -> (node_of (leaf_of el) Empty, 1)
| (tree, depth, pos) when Int32.(equal (shift_left 1l depth) (of_int pos))
->
let t_right = make_spine_with el depth in
(node_of tree t_right, depth + 1)
| (tree, depth, pos) ->
let key = to_bin ~pos ~depth in
(traverse Top tree depth key, depth)
in
{tree = tree'; depth = depth'; next_pos = t.next_pos + 1}
let rec tree_to_list = function
| Empty -> []
| Leaf h -> [h]
| Node (_, t_left, t_right) -> tree_to_list t_left @ tree_to_list t_right
let path_encoding = Data_encoding.(list H.encoding)
let bounded_path_encoding ?max_length () =
match max_length with
| None -> path_encoding
| Some max_length -> Data_encoding.((list ~max_length) H.encoding)
(* The order of the path is from bottom to top *)
let compute_path {tree; depth; next_pos} pos =
if Compare.Int.(pos < 0 || pos >= next_pos) then
error Merkle_list_invalid_position
else
let key = to_bin ~pos ~depth in
let rec aux acc tree key =
match (tree, key) with
| (Leaf _, []) -> ok acc
| (Node (_, l, r), b :: key) ->
if b then aux (root l :: acc) r key else aux (root r :: acc) l key
| _ -> error Merkle_list_invalid_position
in
aux [] tree key
let check_path path pos el expected_root =
let depth = List.length path in
if
Compare.Int.(pos >= 0)
&& Compare.Z.(Z.of_int pos < Z.shift_left Z.one depth)
then
let key = List.rev @@ to_bin ~pos ~depth in
let computed_root =
List.fold_left
(fun acc (sibling, b) ->
if b then hash2 sibling acc else hash2 acc sibling)
(hash_elt el)
(List.combine_drop path key)
in
ok (H.equal computed_root expected_root)
else error Merkle_list_invalid_position
let path_depth path = List.length path
let compute l =
let rec aux l =
let rec pairs acc = function
| [] -> List.rev acc
| [x] -> List.rev (hash2 x empty :: acc)
| x :: y :: xs -> pairs (hash2 x y :: acc) xs
in
match pairs [] l with [] -> empty | [h] -> h | pl -> aux pl
in
aux (List.map hash_elt l)
let root t = root t.tree
module Internal_for_tests = struct
let path_to_list x = x
let to_list tree = tree_to_list tree.tree
let equal t1 t2 =
let rec eq_tree t1 t2 =
match (t1, t2) with
| (Empty, Empty) -> true
| (Leaf h1, Leaf h2) -> H.equal h1 h2
| (Node (h1, l1, r1), Node (h2, l2, r2)) ->
H.equal h1 h2 && eq_tree l1 l2 && eq_tree r1 r2
| _ -> false
in
Compare.Int.equal t1.depth t2.depth
&& Compare.Int.equal t1.next_pos t2.next_pos
&& eq_tree t1.tree t2.tree
end
end
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