[infer][report] fix performance issue when logging events

Reviewed By: dulmarod, jvillard

Differential Revision: D6960795

fbshipit-source-id: c10eca6

infer/src/backend/InferPrint.ml

@@ -536,6 +536,7 @@ module Stats = struct
          ; symops= summary.stats.symops }
        :: stats.events_to_log
 
+
   let num_files stats = Hashtbl.length stats.files
 
   let pp fmt stats =
@@ -1031,7 +1032,7 @@ let finalize_and_close_files format_list_by_kind (stats: Stats.t) =
           let outfile = get_outfile outfile_opt in
           IssuesJson.pp_json_close outfile.fmt ()
       | Logs, Stats ->
-          EventLogger.log_multiple stats.events_to_log
+          List.iter ~f:EventLogger.log stats.events_to_log
       | Csv, (Issues | Procs | Calls | Summary)
       | Logs, (Issues | Procs | Calls | Summary)
       | Json, (Procs | Stats | Calls | Summary)

infer/src/base/EventLogger.ml

@@ -220,12 +220,4 @@ let prepare = IO.prepare
 
 let log event = IO.write "%s\n" (create_row event)
 
-let log_multiple events =
-  let rows = List.map ~f:create_row events in
-  let combinedJson =
-    List.fold_right rows ~init:"" ~f:(fun row combined -> combined ^ row ^ "\n")
-  in
-  IO.write "%s" combinedJson
-
-
 let dump = IO.dump

infer/src/base/EventLogger.mli

@@ -45,6 +45,4 @@ val prepare : unit -> unit
 
 val log : event -> unit
 
-val log_multiple : event list -> unit
-
 val dump : unit -> unit