[utils] return process exit status in with_process_{in,full} helpers

Summary:
It's nice to be able to know how well the process we started did, although this
diff ignores it for now.

Reviewed By: dulmarod

Differential Revision: D3937902

fbshipit-source-id: 80bf20f

infer/src/backend/CommandLineOption.ml

@@ -154,7 +154,7 @@ let align desc_list =
      to read the result from `tput`. *)
   (try Unix.getenv "TERM" |> ignore
    with Not_found -> Unix.putenv "TERM" "ansi");
-  let cur_term_width = try int_of_string (with_process_in "tput cols" input_line)
+  let cur_term_width = try with_process_in "tput cols" input_line |> fst |> int_of_string
     with
     | End_of_file (* tput is unhappy *)
     | Failure "int_of_string" (* not sure if possible *) -> min_term_width in

infer/src/backend/config.ml

@@ -258,6 +258,7 @@ let ncpu =
     with_process_in
       "getconf _NPROCESSORS_ONLN 2>/dev/null"
       (fun chan -> Scanf.fscanf chan "%d" (fun n -> n))
+    |> fst
   with _ ->
     1
 

infer/src/backend/utils.ml

@@ -586,30 +586,42 @@ let read_optional_json_file path =
       Error msg
   else Ok (`Assoc [])
 
+let do_finally f g =
+  let res = try f () with exc -> g () |> ignore; raise exc in
+  let res' = g () in
+  (res, res')
+
 let with_file file ~f =
   let oc = open_out file in
-  try
-    let res = f oc in
-    close_out oc;
-    res
-  with exc ->
-    close_out oc;
-    raise exc
+  let f () = f oc in
+  let g () = close_out oc in
+  do_finally f g
 
 let write_json_to_file destfile json =
   with_file destfile ~f:(fun oc -> Yojson.Basic.pretty_to_channel oc json)
+  |> fst
+
+let consume_in chan_in =
+  try
+    while true do input_line chan_in |> ignore done
+  with End_of_file -> ()
 
 let with_process_in command read =
   let chan = Unix.open_process_in command in
-  let res =
-    try
-      read chan
-    with exc ->
-      Unix.close_process_in chan |> ignore ;
-      raise exc
-  in
-  Unix.close_process_in chan |> ignore ;
-  res
+  let f () = read chan in
+  let g () =
+    consume_in chan;
+    Unix.close_process_in chan in
+  do_finally f g
+
+let with_process_full command read_out read_err =
+  let (out_chan, _, err_chan) as chans = Unix.open_process_full command (Unix.environment ()) in
+  let f () = (read_out out_chan, read_err err_chan) in
+  let g () =
+    consume_in out_chan;
+    consume_in err_chan;
+    Unix.close_process_full chans in
+  do_finally f g
 
 let failwithf fmt =
   Format.kfprintf (fun _ -> failwith (Format.flush_str_formatter ()))

infer/src/backend/utils.mli

@@ -279,7 +279,10 @@ val read_optional_json_file : string -> (Yojson.Basic.json, string) result
 
 val write_json_to_file : string -> Yojson.Basic.json -> unit
 
-val with_process_in: string -> (in_channel -> 'a) -> 'a
+val with_process_in: string -> (in_channel -> 'a) -> ('a * Unix.process_status)
+
+val with_process_full: string -> (in_channel -> 'a) -> (in_channel -> 'b) ->
+  (('a * 'b) * Unix.process_status)
 
 val failwithf : ('a, Format.formatter, unit, 'b) format4 -> 'a
 

infer/src/integration/BuckCompilationDatabase.ml

@@ -168,7 +168,7 @@ let get_compilation_database changed_files =
        let buck_targets_list = buck :: "targets" :: "--show-output" :: args_with_flavor in
        let buck_targets = String.concat " " buck_targets_list in
        try
-         match Utils.with_process_in buck_targets Std.input_list with
+         match fst @@ Utils.with_process_in buck_targets Std.input_list with
          | [] -> Logging.stdout "There are no files to process, exiting."; exit 0
          | lines ->
              let scan_output compilation_database_files chan =