Expose reset_counters in the BuckleScript runtime

See #307 (comment).

src/common/bisect_common.ml

@@ -145,6 +145,14 @@ end
 let table : (string, int array * string) Hashtbl.t Lazy.t =
   lazy (Hashtbl.create 17)
 
+let reset_counters () =
+  Lazy.force table
+  |> Hashtbl.iter begin fun _ (point_state, _) ->
+    match Array.length point_state with
+    | 0 -> ()
+    | n -> Array.fill point_state 0 (n - 1) 0
+  end
+
 let runtime_data_to_string () =
   let data = Hashtbl.fold (fun k v acc -> (k, v)::acc) (Lazy.force table) [] in
   match data with

src/common/bisect_common.mli

@@ -61,8 +61,8 @@ val read_runtime_data : string -> (string * (int array * string)) list
 val read_points : string -> point_definition list
 (** [read_points s] reads point definitions from the string [s]. *)
 
-val table : (string, int array * string) Hashtbl.t Lazy.t
-(** Coverage statistics table used by the runtime. *)
+val reset_counters : unit -> unit
+(** Clears accumulated coverage statistics. *)
 
 val register_file :
   string -> point_count:int -> point_definitions:string ->

src/runtime/bucklescript/runtime.ml

@@ -37,3 +37,6 @@ let node_at_exit = [%bs.raw {|
 
 let write_coverage_data_on_exit () =
   node_at_exit write_coverage_data
+
+let reset_coverage_data =
+  Bisect_common.reset_counters

src/runtime/bucklescript/runtime.mli

@@ -32,3 +32,6 @@ val write_coverage_data : unit -> unit
 val write_coverage_data_on_exit : unit -> unit
 (** Registers {!write_coverage_data} to be called automatically on process
     exit. *)
+
+val reset_coverage_data : unit -> unit
+(** [reset_coverage_data ()] clears accumulated coverage statistics. *)

src/runtime/native/runtime.ml

@@ -94,16 +94,12 @@ let file_channel () =
   in
   create_file ()
 
+let reset_counters =
+  Common.reset_counters
+
 let dump_counters_exn =
   Common.write_runtime_data
 
-let reset_counters () =
-  Hashtbl.iter (fun _ (point_state, _) ->
-      match Array.length point_state with
-      | 0 -> ()
-      | n -> Array.(fill point_state 0 (n - 1) 0)
-    ) (Lazy.force Common.table)
-
 let dump () =
   match file_channel () with
   | None -> ()