[utils] move parts of utils into their own submodules to avoid future dependency cycle

Summary:
This will be needed higher up in the stack because the new `ProcessPool` module
will need to call into `Logging` to refresh the logging formatters to get the
right PID when writing to the log file.

+remove dead code `iter_parallel`

Reviewed By: jberdine

Differential Revision: D5165130

fbshipit-source-id: 95c949b

infer/src/backend/PerfStats.ml

@@ -141,7 +141,7 @@ let stats () =
   }
 
 let register_report_at_exit file =
-  Utils.register_epilogue (fun () ->
+  Epilogues.register ~f:(fun () ->
       try
         let json_stats = to_json (stats ()) in
         try

infer/src/backend/Tasks.ml

@@ -50,21 +50,21 @@ let run t =
 
 module Runner = struct
   type runner =
-    { pool : Utils.ProcessPool.t;
+    { pool : ProcessPool.t;
       all_continuations : closure Queue.t }
 
   let create ~jobs =
-    { pool = Utils.ProcessPool.create ~jobs;
+    { pool = ProcessPool.create ~jobs;
       all_continuations = Queue.create () }
 
   let start runner ~tasks =
     let pool = runner.pool in
     Queue.enqueue_all runner.all_continuations (Queue.to_list tasks.continuations);
     List.iter
-      ~f:(fun x -> Utils.ProcessPool.start_child ~f:(fun f -> f ()) ~pool x)
+      ~f:(fun x -> ProcessPool.start_child ~f:(fun f -> f ()) ~pool x)
       tasks.closures
 
   let complete runner =
-    Utils.ProcessPool.wait_all runner.pool;
+    ProcessPool.wait_all runner.pool;
     Queue.iter ~f:(fun f -> f ()) runner.all_continuations
 end

infer/src/base/Epilogues.ml

@@ -0,0 +1,34 @@
+(*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+open! IStd
+
+module F = Format
+
+(* Run the epilogues when we get SIGINT (Control-C). We do not want to mask SIGINT unless at least
+   one epilogue has been registered, so make this value lazy. *)
+let activate_run_epilogues_on_signal = lazy (
+  let run_epilogues_on_signal s =
+    F.eprintf "*** %s: Caught %s, time to die@." (Filename.basename Sys.executable_name)
+      (Signal.to_string s);
+    (* Epilogues are registered with [at_exit] so exiting will make them run. *)
+    exit 0 in
+  Signal.Expert.handle Signal.int run_epilogues_on_signal
+)
+
+let register ~f desc =
+  let f_no_exn () =
+    if not !ProcessPool.in_child then
+      try
+        f ()
+      with exn ->
+        F.eprintf "Error while running epilogue %s:@ %a.@ Powering through...@." desc Exn.pp exn in
+  (* We call `exit` in a bunch of places, so register the epilogues with [at_exit]. *)
+  Pervasives.at_exit f_no_exn;
+  (* Register signal masking. *)
+  Lazy.force activate_run_epilogues_on_signal

infer/src/base/Epilogues.mli

@@ -0,0 +1,13 @@
+(*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+open! IStd
+
+(** Register a function to run when the program exits or is interrupted. Registered functions are
+    run in the reverse order in which they were registered. *)
+val register : f:(unit -> unit) -> string -> unit

infer/src/base/Logging.ml

@@ -68,8 +68,8 @@ let create_log_file command name_prefix =
   if Config.print_logs then (
     dup_formatter file_fmt Format.err_formatter
   );
-  Utils.register_epilogue
-    (fun () -> close_log_file (lazy file_fmt) (lazy chan) (lazy file))
+  Epilogues.register
+    ~f:(fun () -> close_log_file (lazy file_fmt) (lazy chan) (lazy file))
     "log files flushing";
   (file_fmt, chan, file)
 

infer/src/base/ProcessPool.ml

@@ -0,0 +1,52 @@
+(*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+open! IStd
+
+(* Keep track of whether the current execution is in a child process *)
+let in_child = ref false
+
+type t =
+  {
+    mutable num_processes : int;
+    jobs : int;
+  }
+let create ~jobs =
+  {
+    num_processes = 0;
+    jobs;
+  }
+
+let incr counter =
+  counter.num_processes <- counter.num_processes + 1
+
+let decr counter =
+  counter.num_processes <- counter.num_processes - 1
+
+let wait counter =
+  let _ = Unix.wait `Any in
+  decr counter
+
+let wait_all counter =
+  for _ = 1 to counter.num_processes do
+    wait counter
+  done
+
+let should_wait counter =
+  counter.num_processes >= counter.jobs
+
+let start_child ~f ~pool x =
+  match Unix.fork () with
+  | `In_the_child ->
+      in_child := true;
+      f x;
+      exit 0
+  | `In_the_parent _pid ->
+      incr pool;
+      if should_wait pool
+      then wait pool

infer/src/base/ProcessPool.mli

@@ -0,0 +1,24 @@
+(*
+ * Copyright (c) 2017 - present Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ *)
+open! IStd
+
+(** Pool of processes to execute in parallel up to a number of jobs. *)
+type t
+
+(** Create a new pool of processes *)
+val create : jobs:int -> t
+
+(** Start a new child process in the pool.
+    If all the jobs are taken, wait until one is free. *)
+val start_child : f:('a -> unit) -> pool:t -> 'a -> unit
+
+(** Wait until all the currently executing processes terminate *)
+val wait_all : t -> unit
+
+val in_child : bool ref

infer/src/base/Utils.ml

@@ -296,78 +296,3 @@ let compare_versions v1 v2 =
   let lv1  = int_list_of_version v1 in
   let lv2  = int_list_of_version v2 in
   [%compare : int list] lv1 lv2
-
-(* Run the epilogues when we get SIGINT (Control-C). We do not want to mask SIGINT unless at least
-   one epilogue has been registered, so make this value lazy. *)
-let activate_run_epilogues_on_signal = lazy (
-  let run_epilogues_on_signal s =
-    F.eprintf "*** %s: Caught %s, time to die@." (Filename.basename Sys.executable_name)
-      (Signal.to_string s);
-    (* Epilogues are registered with [at_exit] so exiting will make them run. *)
-    exit 0 in
-  Signal.Expert.handle Signal.int run_epilogues_on_signal
-)
-
-(* Keep track of whether the current execution is in a child process *)
-let in_child = ref false
-
-module ProcessPool = struct
-  type t =
-    {
-      mutable num_processes : int;
-      jobs : int;
-    }
-  let create ~jobs =
-    {
-      num_processes = 0;
-      jobs;
-    }
-
-  let incr counter =
-    counter.num_processes <- counter.num_processes + 1
-
-  let decr counter =
-    counter.num_processes <- counter.num_processes - 1
-
-  let wait counter =
-    let _ = Unix.wait `Any in
-    decr counter
-
-  let wait_all counter =
-    for _ = 1 to counter.num_processes do
-      wait counter
-    done
-
-  let should_wait counter =
-    counter.num_processes >= counter.jobs
-
-  let start_child ~f ~pool x =
-    match Unix.fork () with
-    | `In_the_child ->
-        in_child := true;
-        f x;
-        exit 0
-    | `In_the_parent _pid ->
-        incr pool;
-        if should_wait pool
-        then wait pool
-end
-
-let iteri_parallel ~f ?(jobs=1) l =
-  let pool = ProcessPool.create ~jobs in
-  List.iteri ~f:(fun i x -> ProcessPool.start_child ~f:(f i) ~pool x) l;
-  ProcessPool.wait_all pool
-
-let iter_parallel ~f ?(jobs=1) l =
-  iteri_parallel ~f:(fun _ x -> f x) ~jobs l
-
-let register_epilogue f desc =
-  let f_no_exn () =
-    if not !in_child then
-      try f ()
-      with exn ->
-        F.eprintf "Error while running epilogue %s:@ %a.@ Powering through...@." desc Exn.pp exn in
-  (* We call `exit` in a bunch of places, so register the epilogues with [at_exit]. *)
-  Pervasives.at_exit f_no_exn;
-  (* Register signal masking. *)
-  Lazy.force activate_run_epilogues_on_signal

infer/src/base/Utils.mli

@@ -83,28 +83,3 @@ val suppress_stderr2 : ('a -> 'b -> 'c) -> 'a -> 'b -> 'c
     -1 if v1 is older than v2 and 0 if they are the same version.
     The versions are strings of the shape "n.m.t", the order is lexicographic. *)
 val compare_versions : string -> string -> int
-
-(** Like List.iter but operates in parallel up to a number of jobs *)
-val iter_parallel : f:('a -> unit) -> ?jobs:int -> 'a list -> unit
-
-(** Like List.iteri but operates in parallel up to a number of jobs *)
-val iteri_parallel : f:(int -> 'a -> unit) -> ?jobs:int -> 'a list -> unit
-
-(** Pool of processes to execute in parallel up to a number of jobs. *)
-module ProcessPool : sig
-  type t
-
-  (** Create a new pool of processes *)
-  val create : jobs:int -> t
-
-  (** Start a new child process in the pool.
-      If all the jobs are taken, wait until one is free. *)
-  val start_child : f:('a -> unit) -> pool:t -> 'a -> unit
-
-  (** Wait until all the currently executing processes terminate *)
-  val wait_all : t -> unit
-end
-
-(** Register a function to run when the program exits or is interrupted. Registered functions are
-    run in the reverse order in which they were registered. *)
-val register_epilogue : (unit -> unit) -> string -> unit

infer/src/integration/Maven.ml

@@ -132,13 +132,13 @@ let add_profile_to_pom_in_directory dir =
   let infer_pom_path = dir ^/ "pom.xml.infer" in
   add_infer_profile maven_pom_path infer_pom_path;
   Unix.rename ~src:maven_pom_path ~dst:saved_pom_path;
-  Utils.register_epilogue
-    (fun () -> Unix.rename ~src:saved_pom_path ~dst:maven_pom_path)
+  Epilogues.register
+    ~f:(fun () -> Unix.rename ~src:saved_pom_path ~dst:maven_pom_path)
     "restoring Maven's pom.xml to its original state";
   Unix.rename ~src:infer_pom_path ~dst:maven_pom_path;
   if Config.debug_mode || Config.stats_mode then
-    Utils.register_epilogue
-      (fun () -> Unix.rename ~src:maven_pom_path ~dst:infer_pom_path)
+    Epilogues.register
+      ~f:(fun () -> Unix.rename ~src:maven_pom_path ~dst:infer_pom_path)
       "saving infer's pom.xml"
 
 let capture ~prog ~args =