Re: yesno module consumes too much input

[Eric Blake]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

According to Jim Meyering on 8/19/2007 12:47 AM:
>> Jim, you are affected the most - which would you rather see, a relatively
>> big patch to yesno/closein that potentially changes API, or a one-line
>> patch to each of your five affected programs?
> 
> The complexity of the yesno-modifying approach seems too high,
> and not limited just to yesno, so I think the per-application
> one-line changes are better.

Here's what I'm committing to gnulib; a patch for coreutils will follow.

2007-08-19  Eric Blake  <address@hidden>

        Test yesno in combination with closein.
        * lib/yesno.c (yesno): Document use of stdin.
        * modules/yesno-tests (Files): New module.
        * tests/test-yesno.c (main): New file.
        * tests/test-yesno.sh: Likewise.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.5 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iD8DBQFGyGEc84KuGfSFAYARAktLAKCEpwYZTx1AXP93bB12nZDLHPKTdACgtmpc
xTz7FUZG5iqa68XreZ0t+YI=
=9W1R
-----END PGP SIGNATURE-----

Index: lib/yesno.c
===================================================================
RCS file: /sources/gnulib/gnulib/lib/yesno.c,v
retrieving revision 1.17
diff -u -p -r1.17 yesno.c
--- lib/yesno.c 14 Dec 2006 18:47:36 -0000      1.17
+++ lib/yesno.c 19 Aug 2007 15:07:18 -0000
@@ -1,6 +1,6 @@
 /* yesno.c -- read a yes/no response from stdin
 
-   Copyright (C) 1990, 1998, 2001, 2003, 2004, 2005, 2006 Free
+   Copyright (C) 1990, 1998, 2001, 2003, 2004, 2005, 2006, 2007 Free
    Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
@@ -28,10 +28,14 @@
 # include "getline.h"
 #endif
 
-/* Return true if we read an affirmative line from standard input.  */
-
 extern int rpmatch (char const *response);
 
+/* Return true if we read an affirmative line from standard input.
+
+   Since this function uses stdin, it is suggested that the caller not
+   use STDIN_FILENO directly, and also that the line
+   atexit(close_stdin) be added to main().  */
+
 bool
 yesno (void)
 {
Index: modules/yesno-tests
===================================================================
RCS file: modules/yesno-tests
diff -N modules/yesno-tests
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ modules/yesno-tests 19 Aug 2007 15:07:18 -0000
@@ -0,0 +1,15 @@
+Files:
+tests/test-yesno.c
+tests/test-yesno.sh
+
+Depends-on:
+closein
+
+configure.ac:
+
+Makefile.am:
+TESTS += test-yesno.sh
+TESTS_ENVIRONMENT += EXEEXT='@EXEEXT@'
+check_PROGRAMS += test-yesno
+EXTRA_DIST += test-yesno.sh
+test_yesno_LDADD = $(LDADD) @LIBINTL@
Index: tests/test-yesno.c
===================================================================
RCS file: tests/test-yesno.c
diff -N tests/test-yesno.c
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ tests/test-yesno.c  19 Aug 2007 15:07:18 -0000
@@ -0,0 +1,51 @@
+/* Test of yesno module.
+   Copyright (C) 2007 Free Software Foundation, Inc.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3, or (at your option)
+   any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "closein.h"
+#include "yesno.h"
+
+char *program_name;
+
+/* Test yesno.  Without arguments, read one line.  If first argument
+   is zero, close stdin before attempting to read one line.
+   Otherwise, read the number of lines specified by first
+   argument.  */
+int
+main (int argc, char **argv)
+{
+  int i = 1;
+  program_name = argv[0];
+  /* yesno recommends that all clients use close_stdin in main.  */
+  atexit (close_stdin);
+
+  if (1 < argc)
+    i = atoi (argv[1]);
+  if (!i)
+    {
+      i = 1;
+      close (0);
+    }
+  while (i--)
+    puts (yesno () ? "Y" : "N");
+  return 0;
+}
Index: tests/test-yesno.sh
===================================================================
RCS file: tests/test-yesno.sh
diff -N tests/test-yesno.sh
--- /dev/null   1 Jan 1970 00:00:00 -0000
+++ tests/test-yesno.sh 19 Aug 2007 15:07:18 -0000
@@ -0,0 +1,58 @@
+#!/bin/sh
+
+tmpfiles=
+trap 'rm -fr $tmpfiles' 1 2 3 15
+
+p=t-yesno-
+tmpfiles="${p}in.tmp ${p}xout.tmp ${p}out.tmp"
+
+# For now, only test with C locale
+LC_ALL=C
+export LC_ALL
+
+# Test with seekable stdin; followon process must see remaining data
+cat <<EOF > ${p}in.tmp
+nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn - entire line consumed
+yn - backspace does not change result
+y
+does not match either yesexpr or noexpr
+n
+EOF
+cat <<EOF > ${p}xout.tmp
+N
+Y
+Y
+N
+n
+EOF
+(./test-yesno${EXEEXT}; ./test-yesno${EXEEXT} 3; cat) \
+  < ${p}in.tmp > ${p}out.tmp || exit 1
+cmp ${p}xout.tmp ${p}out.tmp || exit 1
+
+(./test-yesno${EXEEXT} 3; ./test-yesno${EXEEXT}; cat) \
+  < ${p}in.tmp > ${p}out.tmp || exit 1
+cmp ${p}xout.tmp ${p}out.tmp || exit 1
+
+# Test for behavior on pipe
+cat <<EOF > ${p}xout.tmp
+Y
+N
+EOF
+echo yes | ./test-yesno${EXEEXT} 2 > ${p}out.tmp || exit 1
+cmp ${p}xout.tmp ${p}out.tmp || exit 1
+
+# Test for behavior on EOF
+cat <<EOF > ${p}xout.tmp
+N
+EOF
+./test-yesno${EXEEXT} </dev/null > ${p}out.tmp || exit 1
+cmp ${p}xout.tmp ${p}out.tmp || exit 1
+
+# Test for behavior when stdin is closed
+./test-yesno${EXEEXT} 0 <&- > ${p}out.tmp && exit 1
+cmp ${p}xout.tmp ${p}out.tmp || exit 1
+
+# Cleanup
+rm -fr $tmpfiles
+
+exit 0