Add copy to the storage

src/lib_protocol_environment/sigs/v1/context.mli

@@ -25,6 +25,9 @@ val get: t -> key -> value option Lwt.t
 
 val set: t -> key -> value -> t Lwt.t
 
+(** [copy] returns None if the [from] key is not bound *)
+val copy: t -> from:key -> to_:key -> t option Lwt.t
+
 val del: t -> key -> t Lwt.t
 val remove_rec: t -> key -> t Lwt.t
 

src/lib_protocol_environment/tezos_protocol_environment.ml

@@ -17,6 +17,7 @@ module type CONTEXT = sig
   val dir_mem: t -> key -> bool Lwt.t
   val get: t -> key -> value option Lwt.t
   val set: t -> key -> value -> t Lwt.t
+  val copy: t -> from:key -> to_:key -> t option Lwt.t
   val del: t -> key -> t Lwt.t
   val remove_rec: t -> key -> t Lwt.t
   val fold:

src/lib_protocol_environment/tezos_protocol_environment.mli

@@ -10,6 +10,7 @@ module type CONTEXT = sig
   val dir_mem: t -> key -> bool Lwt.t
   val get: t -> key -> value option Lwt.t
   val set: t -> key -> value -> t Lwt.t
+  val copy: t -> from:key -> to_:key -> t option Lwt.t
   val del: t -> key -> t Lwt.t
   val remove_rec: t -> key -> t Lwt.t
   val fold:

src/lib_protocol_environment/tezos_protocol_environment_faked.ml

@@ -16,6 +16,7 @@ module Context = struct
   let dir_mem _ _ = assert false
   let get _ _ = assert false
   let set _ _ _ = assert false
+  let copy _ ~from:_ ~to_:_ = assert false
   let del _ _ = assert false
   let remove_rec _ _ = assert false
   let fold _ _ ~init:_ ~f:_ = assert false

src/lib_protocol_environment/tezos_protocol_environment_memory.ml

@@ -86,6 +86,10 @@ module Context = struct
     match raw_set m k None with
     | None -> Lwt.return m
     | Some m -> Lwt.return m
+  let copy m ~from ~to_ =
+    match raw_get m from with
+    | None -> Lwt.return_none
+    | Some v -> Lwt.return (raw_set m to_ (Some v))
 
   let fold m k ~init ~f =
     match raw_get m k with

src/lib_storage/context.ml

@@ -157,6 +157,13 @@ let remove_rec ctxt key =
   GitStore.Tree.remove ctxt.tree (data_key key) >>= fun tree ->
   Lwt.return { ctxt with tree }
 
+let copy ctxt ~from ~to_ =
+  GitStore.Tree.find_tree ctxt.tree (data_key from) >>= function
+  | None -> Lwt.return_none
+  | Some sub_tree ->
+      GitStore.Tree.add_tree ctxt.tree (data_key to_) sub_tree >>= fun tree ->
+      Lwt.return_some { ctxt with tree }
+
 let fold ctxt key ~init ~f =
   GitStore.Tree.list ctxt.tree (data_key key) >>= fun keys ->
   Lwt_list.fold_left_s

src/lib_storage/context.mli

@@ -45,6 +45,9 @@ val set: context -> key -> value -> t Lwt.t
 val del: context -> key -> t Lwt.t
 val remove_rec: context -> key -> t Lwt.t
 
+(** [copy] returns None if the [from] key is not bound *)
+val copy: context -> from:key -> to_:key -> context option Lwt.t
+
 val fold:
   context -> key -> init:'a ->
   f:([ `Key of key | `Dir of key ] -> 'a -> 'a Lwt.t) ->