improve CCUnix a bit

src/unix/CCUnix.ml

@@ -77,7 +77,7 @@ type call_result =
 
 let kbprintf' buf fmt k = Printf.kbprintf k buf fmt
 
-let call ?(bufsize=2048) ?(stdin=`Str "") ?(env=Unix.environment()) cmd =
+let call_full_inner ?(bufsize=2048) ?(stdin=`Str "") ?(env=Unix.environment()) ~f cmd =
   (* render the command *)
   let buf = Buffer.create 256 in
   kbprintf' buf cmd
@@ -94,13 +94,26 @@ let call ?(bufsize=2048) ?(stdin=`Str "") ?(env=Unix.environment()) cmd =
         let out = read_all ~size:bufsize oc in
         let err = read_all ~size:bufsize errc in
         let status = Unix.close_process_full (oc, ic, errc) in
+        f (out,err,status)
+    )
+
+let call_full ?bufsize ?stdin ?env cmd =
+  call_full_inner ?bufsize ?stdin ?env cmd
+    ~f:(fun (out,err,status) ->
         object
           method stdout = out
           method stderr = err
           method status = status
           method errcode = int_of_process_status status
-        end
-    )
+        end)
+
+let call ?bufsize ?stdin ?env cmd =
+  call_full_inner ?bufsize ?stdin ?env cmd
+    ~f:(fun (out,err,status) -> out, err, int_of_process_status status)
+
+let call_stdout ?bufsize ?stdin ?env cmd =
+  call_full_inner ?bufsize ?stdin ?env cmd
+    ~f:(fun (out,_err,_status) -> out)
 
 type line = string
 
@@ -212,7 +225,7 @@ let establish_server sockaddr ~f =
   done
 
 module Infix = struct
-  let (?|) fmt = call fmt
+  let (?|) fmt = call_full fmt
 
   let (?|&) fmt = async_call fmt
 end

src/unix/CCUnix.mli

@@ -29,12 +29,13 @@ type call_result =
     errcode:int; (** Extracted from status *)
   >
 
-val call : ?bufsize:int ->
+val call_full :
+  ?bufsize:int ->
   ?stdin:[`Gen of string gen | `Str of string] ->
   ?env:string array ->
   ('a, Buffer.t, unit, call_result) format4 ->
   'a
-(** [call cmd] wraps the result of [Unix.open_process_full cmd] into an
+(** [call_full cmd] wraps the result of [Unix.open_process_full cmd] into an
     object. It reads the full stdout and stderr of the subprocess before
     returning.
     @param stdin if provided, the generator or string is consumed and fed to
@@ -44,9 +45,31 @@ val call : ?bufsize:int ->
 *)
 
 (*$T
-  (call ~stdin:(`Str "abc") "cat")#stdout = "abc"
-  (call "echo %s" (escape_str "a'b'c"))#stdout = "a'b'c\n"
-  (call "echo %s" "a'b'c")#stdout = "abc\n"
+  call_full ~stdin:(`Str "abc") "cat" |> stdout = "abc"
+  call_full "echo %s" (escape_str "a'b'c") |> stdout = "a'b'c\n"
+  call_full "echo %s" "a'b'c" |> stdout = "abc\n"
+*)
+
+val call :
+  ?bufsize:int ->
+  ?stdin:[`Gen of string gen | `Str of string] ->
+  ?env:string array ->
+  ('a, Buffer.t, unit, string * string * int) format4 ->
+  'a
+(** [call cmd] is similar to [call_full cmd] but returns
+    a tuple [stdout, stderr, errcode] instead of an object. *)
+
+val call_stdout :
+  ?bufsize:int ->
+  ?stdin:[`Gen of string gen | `Str of string] ->
+  ?env:string array ->
+  ('a, Buffer.t, unit, string) format4 ->
+  'a
+
+(*$T
+  call_stdout ~stdin:(`Str "abc") "cat" = "abc"
+  call_stdout "echo %s" (escape_str "a'b'c") = "a'b'c\n"
+  call_stdout "echo %s" "a'b'c" = "abc\n"
 *)
 
 type line = string
@@ -103,6 +126,9 @@ val with_out : ?mode:int -> ?flags:Unix.open_flag list ->
 
 val with_process_in : string -> f:(in_channel -> 'a) -> 'a
 (** Open a subprocess and obtain a handle to its stdout
+    {[
+      CCUnix.with_process_in "ls /tmp" ~f:CCIO.read_lines_l;;
+    ]}
     @since 0.16 *)
 
 val with_process_out : string -> f:(out_channel -> 'a) -> 'a
@@ -115,7 +141,7 @@ type process_full = <
   stdin: out_channel;
   stdout: in_channel;
   stderr: in_channel;
-  close: Unix.process_status;
+  close: Unix.process_status; (** Will block until the process stops *)
 >
 
 val with_process_full : ?env:string array -> string -> f:(process_full -> 'a) -> 'a