[Quilt-dev] Re: remove GNU date dependency [Was: quilt mail broken with sed 3.02]

[Gary V. Vaughan]

Andreas Gruenbacher wrote:
> Gary,

Morgen!

> I've looked into this a little, and standard date(1) doesn't have the -d 
> option, and doesn't support `%s' and `%z'. We could get of the first use of 
> -d, but incrementing timestamps is harder, and I'd hate to have to sleep a 
> second between each date generated just to get a different timestamp. We 
> could put the same timestamp in each message in case we can't increment, but 
> then, we still can't generate `%z'. The Perl workaround also relies on 
> strftime(3), which probably is the platform's native libc implementation, and 
> so probably has the same limitations as date(1).

Apparently, perl doesn't use the native strftime... or at least on darwin %z
works within perl, but isn't used in Apple's date implementation.

> The following snipped computes %z in shell code, but this doesn't solve the 
> increment-timestamp problem.
> 
>       zone_offset=
>       while [ "${zone_offset%0}" = "$zone_offset" ]
>       do
>               zone_offset=$(( 9$(date '+%H%M') - 9$(date -u '+%H%M') ))
>       done
>       printf '+%04d\n' $zone_offset
> 
> So I think I'll go with 0.43 even though this portability issue is not fixed.

Here is a patch for a perl date wrapper (my first perl script!), I hope you
can commit this in time for 0.43...  with it, I can `./configure --without-date'
and have the testsuite complete successfully.

Cheers,
        Gary.
-- 
Gary V. Vaughan      ())_.  address@hidden,gnu.org}
Research Scientist   ( '/   http://tkd.kicks-ass.net
GNU Hacker           / )=   http://www.gnu.org/software/libtool
Technical Author   `(_~)_   http://sources.redhat.com/autobook

 compat/date.in |   78 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 configure.ac   |   15 ++++++++++
 2 files changed, 93 insertions(+)

Index: quilt-HEAD/compat/date.in
===================================================================
--- /dev/null
+++ quilt-HEAD/compat/date.in
@@ -0,0 +1,78 @@
+#! @PERL@ -w
+
+#  This script is free software; you can redistribute it and/or modify
+#  it under the terms of the GNU General Public License version 2 as
+#  published by the Free Software Foundation.
+#
+#  See the COPYING and AUTHORS files for more details.
+
+use strict;
+use POSIX qw(strftime);
+use Getopt::Long;
+
+my %opt = ();
+my $spec = '%a %b %e %H:%M:%S %Z %Y';
+my $now  = time();
+
+sub usage() {
+    print "Usage: date [OPTION]... [+FORMAT]
+Display the current time in the given FORMAT.
+
+  -d, --date=STRING         display time described by STRING, not `now'
+  -f, --file=DATEFILE       like --date once for each line of DATEFILE
+  -R, --rfc-2822            output RFC-2822 compliant date string
+  -u, --utc, --universal    print or set Coordinated Universal Time
+      --help                display this help and exit
+";
+    exit;
+}
+
+sub parse_utc_secs() {
+    use Date::Parse;
+
+    my ($now) = @_;
+
+    if ($now =~ / [0-9]+ seconds$/) {
+       # This is an heuristic specifically for quilts mail.in invocation:
+       #   date --rfc-822 -d "1970/01/01 UTC nnnnnnnn seconds"
+       $opt{'utc'} = 1 if ($now =~ / (UTC|GMT) /);
+       $now =~ s/^.* ([0-9]+) seconds$/$1/;
+    }
+    else {
+        $now = str2time($now);
+    }
+
+    return $now;
+}
+
+Getopt::Long::Configure ("bundling", "pass_through");
+
+GetOptions (\%opt, 'rfc-822|R', 'utc|universal|u', 'date|d=s', 'help|h');
+
+my $argc = $#ARGV + 1;
+
+&usage if ($argc > 1 || ($argc == 1 && $ARGV[0] !~ /^\+/));
+
+for my $key ( keys %opt ) {
+    if    ($key =~ /rfc-822/)  { $spec = '%a, %d %b %Y %H:%M:%S %z'; }
+    elsif ($key =~ /utc/)      { ; }
+    elsif ($key =~ /date/)     { $now = &parse_utc_secs($opt{'date'}); }
+    elsif ($key =~ /help/)     { &usage(); }
+    else {
+       die "unknown option `$key'";
+    }
+}
+
+if ($argc == 1) {
+    $spec = substr($ARGV[0], 1);
+}
+
+my @now = ();
+if (exists($opt{'utc'})) {
+    @now = gmtime($now);
+}
+else {
+    @now = localtime($now);
+}
+
+print strftime($spec, @now) . "\n";
Index: quilt-HEAD/configure.ac
===================================================================
--- quilt-HEAD.orig/configure.ac
+++ quilt-HEAD/configure.ac
@@ -82,6 +82,21 @@ duplicates.  You can download GNU coreut
 fi
 
 QUILT_COMPAT_PROG_PATH(DATE, date, [gdate date])
+
+if test -z "$INTERNAL_DATE"; then
+  AC_MSG_CHECKING([whether $DATE --rfc-822 works])
+  if date --rfc-822 >/dev/null 2>&1; then
+       AC_MSG_RESULT(yes)
+  else
+       AC_MSG_ERROR([no
+
+If you don't have a version of `date' that supports --rfc-822, you
+can specify '--without-date' and $PACKAGE_NAME will use its own
+internal date.
+])
+  fi
+fi
+
 QUILT_COMPAT_PROG_PATH(PERL, perl, [perl perl5])
 QUILT_COMPAT_PROG_PATH(GREP, grep)

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