Unix: add open_process_args{,_in,_out,_full} (#1792)

The idea is to add a variant of the Unix.open_process{,_in,_out,_full} functions that work with a pair (program, args) directly, without going through the system shell, which introduces extra complexity (in particular, with respect to quoting).

I used the name Unix.open_process_args which is the one suggested in ocaml-batteries-team/batteries-included#858, but I am not completely sold on it.

One uses the usual "close" functions Unix.close_process{,_in,_out,_full} with the new functions as well.

The "old" functions Unix.open_process{,_in,_out,_full} are re-implemented in terms of the "new" functions, so I did not feel pressed to add new tests.

Addresses: MPR#7794.

1 files changed, 35 insertions, 0 deletions

diff --git a/otherlibs/unix/unixLabels.mli b/otherlibs/unix/unixLabels.mli
index a78738bbb6..cdfecc8962 100644
--- a/otherlibs/unix/unixLabels.mli
+++ b/otherlibs/unix/unixLabels.mli
@@ -666,6 +666,41 @@ val open_process_full :
    of channels connected respectively to the standard output, standard input,
    and standard error of the command. *)
 
+val open_process_args_in : string -> string array -> in_channel
+(** High-level pipe and process management. The first argument specifies the
+   command to run, and the second argument specifies the argument array passed
+   to the command.  This function runs the command in parallel with the program.
+   The standard output of the command is redirected to a pipe, which can be read
+   via the returned input channel.
+
+    @since 4.08.0 *)
+
+val open_process_args_out : string -> string array -> out_channel
+(** Same as {!Unix.open_process_args_in}, but redirect the standard input of the
+   command to a pipe.  Data written to the returned output channel is sent to
+   the standard input of the command.  Warning: writes on output channels are
+   buffered, hence be careful to call {!Pervasives.flush} at the right times to
+   ensure correct synchronization.
+
+    @since 4.08.0 *)
+
+val open_process_args : string -> string array -> in_channel * out_channel
+(** Same as {!Unix.open_process_args_out}, but redirects both the standard input
+   and standard output of the command to pipes connected to the two returned
+   channels.  The input channel is connected to the output of the command, and
+   the output channel to the input of the command.
+
+    @since 4.08.0 *)
+
+val open_process_args_full :
+  string -> string array -> string array -> in_channel * out_channel * in_channel
+(** Similar to {!Unix.open_process_args}, but the third argument specifies the
+   environment passed to the command.  The result is a triple of channels
+   connected respectively to the standard output, standard input, and standard
+   error of the command.
+
+    @since 4.08.0 *)
+
 val close_process_in : in_channel -> process_status
 (** Close channels opened by {!UnixLabels.open_process_in},
    wait for the associated command to terminate,