#!/usr/bin/perl

# Convert git log output to ChangeLog format.

my $VERSION = '2008-12-21 12:07'; # UTC

# The definition above must lie within the first 8 lines in order

# for the Emacs time-stamp write hook (at end) to update it.

# If you change this file with Emacs, please let the write hook

# do its job.  Otherwise, update this string manually.

# Copyright (C) 2008 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 of the License, 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/>.

# Written by Jim Meyering

use strict;

use warnings;

use Getopt::Long;

use POSIX qw(strftime);

(my $ME = $0) =~ s|.*/||;

# use File::Coda; # http://meyering.net/code/Coda/

END {

  defined fileno STDOUT or return;

  close STDOUT and return;

  warn "$ME: failed to close standard output: $!\n";

  $? ||= 1;

}

sub usage ($)

{

  my ($exit_code) = @_;

  my $STREAM = ($exit_code == 0 ? *STDOUT : *STDERR);

  if ($exit_code != 0)

    {

      print $STREAM "Try `$ME --help' for more information.\n";

    }

  else

    {

      print $STREAM <

Usage: $ME [OPTIONS] [ARGS]

Convert git log output to ChangeLog format.  If present, any ARGS

are passed to "git log".  To avoid ARGS being parsed as options to

$ME, they may be preceded by '--'.

OPTIONS:

   --since=DATE convert only the logs since DATE;

                  the default is to convert all log entries.

   --help       display this help and exit

   --version    output version information and exit

EXAMPLE:

  $ME --since=2008-01-01 > ChangeLog

  $ME -- -n 5 foo > last-5-commits-to-branch-foo

EOF

    }

  exit $exit_code;

}

# If the string $S is a well-behaved file name, simply return it.

# If it contains white space, quotes, etc., quote it, and return the new string.

sub shell_quote($)

{

  my ($s) = @_;

  if ($s =~ m![^\w+/.,-]!)

    {

      # Convert each single quote to '\''

      $s =~ s/\'/\'\\\'\'/g;

      # Then single quote the string.

      $s = "'$s'";

    }

  return $s;

}

sub quoted_cmd(@)

{

  return join (' ', map {shell_quote $_} @_);

}

{

  my $since_date = '1970-01-01 UTC';

  GetOptions

    (

     help => sub { usage 0 },

     version => sub { print "$ME version $VERSION\n"; exit },

     'since=s' => \$since_date,

    ) or usage 1;

  my @cmd = (qw (git log --log-size), "--since=$since_date",

             '--pretty=format:%ct  %an  <%ae>%n%n%s%n%b%n', @ARGV);

  open PIPE, '-|', @cmd

    or die ("$ME: failed to run `". quoted_cmd (@cmd) ."': $!\n"

            . "(Is your Git too old?  Version 1.5.1 or later is required.)\n");

  my $prev_date_line = '';

  while (1)

    {

      defined (my $in = <PIPE>)

        or last;

      $in =~ /^log size (\d+)$/

        or die "$ME:$.: Invalid line (expected log size):\n$in";

      my $log_nbytes = $1;

      my $log;

      my $n_read = read PIPE, $log, $log_nbytes;

      $n_read == $log_nbytes

        or die "$ME:$.: unexpected EOF\n";

      my @line = split "\n", $log;

      my $author_line = shift @line;

      defined $author_line

        or die "$ME:$.: unexpected EOF\n";

      $author_line =~ /^(\d+)  (.*>)$/

        or die "$ME:$.: Invalid line "

          . "(expected date/author/email):\n$author_line\n";

      my $date_line = sprintf "%s  $2\n", strftime ("%F", localtime ($1));

      # If this line would be the same as the previous date/name/email

      # line, then arrange not to print it.

      if ($date_line ne $prev_date_line)

        {

          $prev_date_line eq ''

            or print "\n";

          print $date_line;

        }

      $prev_date_line = $date_line;

      # Omit "Signed-off-by..." lines.

      @line = grep !/^Signed-off-by: .*>$/, @line;

      # Remove leading and trailing blank lines.

      while ($line[0] =~ /^\s*$/) { shift @line; }

      while ($line[$#line] =~ /^\s*$/) { pop @line; }

      # Prefix each non-empty line with a TAB.

      @line = map { length $_ ? "\t$_" : '' } @line;

      print "\n", join ("\n", @line), "\n";

      defined ($in = <PIPE>)

        or last;

      $in ne "\n"

        and die "$ME:$.: unexpected line:\n$in";

    }

  close PIPE

    or die "$ME: error closing pipe from " . quoted_cmd (@cmd) . "\n";

  # FIXME-someday: include $PROCESS_STATUS in the diagnostic

}

# Local Variables:

# indent-tabs-mode: nil

# eval: (add-hook 'write-file-hooks 'time-stamp)

# time-stamp-start: "my $VERSION = '"

# time-stamp-format: "%:y-%02m-%02d %02H:%02M"

# time-stamp-time-zone: "UTC"

# time-stamp-end: "'; # UTC"

# End: