git2changelog

#!/bin/sh
#
# ggcov - A GTK frontend for exploring gcov coverage data
# Copyright (c) 2001-2011 Greg Banks <gnb@users.sourceforge.net>
# 
# 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 2 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, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# 
# Shell script to build a change log for a new release
# from git logs. The change log will still need some
# manual editing to re-express changes for users, etc.
#

REV1=
REV2=
PACKAGE=`sed -n -e 's|^AM_INIT_AUTOMAKE(\([^,]\+\),\([^)]\+\))|\1|p' < configure.in`
DRYRUN=no
NREVS=0
ME="Greg Banks"
EMAIL="gnb@users.sourceforge.net"
DATE_FORMAT="%a %b %_d %H:%M:%S %Y"
CHECKFILE="configure.in"
LOG=ChangeLog
OLDLOG=ChangeLog.$$
VERBOSE=0

canon_tag ()
{
    # Usage: canon_tag rev
    echo "${PACKAGE}_$1" | tr a-z. A-Z_
}

get_last_rev_tag ()
{
    git describe --tags HEAD | cut -d- -f1
}

get_rev_date ()
{
    # Usage: get_rev_data rev
    local tag
    local gitdate

    tag=`canon_tag $1`
    gitdate=`git show --pretty='format:%at' $tag | sed -n -e '1s/ .0000$//p'`
    date +"$DATE_FORMAT" -d "$gitdate"
}

usage ()
{
    [ -z "$*" ] || echo "git2changelog: $*"
    echo "Usage: git2changelog [--package pkg] [--dryrun] [rev1 [rev2]]"
    exit 0
}

while [ $# -gt 0 ]; do
    case "$1" in
    --package=*) PACKAGE=`echo "$1"|sed -e 's|^[^=]*=||g'` ;;
    --package) PACKAGE="$2" ; shift ;;
    --dryrun) DRYRUN=yes ;;
    --help) usage ;;
    --verbose) VERBOSE=1 ;;
    -*) usage "bad option \"$1\"" ;;
    [0-9]*.[0-9]*.[0-9]*|[0-9]*.[0-9]*)
    	case "$NREVS" in
	0) REV1="$1" ;;
	1) REV2="$1" ;;
	*) usage "too many revisions at \"$1\"" ;;
	esac
	NREVS=`expr $NREVS + 1`
	;;
    *) usage "unexpected argument at \"$1\"" ;;
    esac
    shift
done

test -z "$PACKAGE" && usage "no package specified"

if [ -z "$REV1" ]; then
    # calculate previous tagged revision by getting
    # most recent tag of the correct format
    TAG1=`get_last_rev_tag`
else
    TAG1=`canon_tag "$REV1"`
fi

if [ -z "$REV2" ]; then
    # Use the magic tag `HEAD' which indicates the
    # most recent revision
    TAG2="HEAD"
    REV2="latest revision"
    DATE=`date +"$DATE_FORMAT"`
    RELEASE=
else
    TAG2=`canon_tag "$REV2"`
    DATE=`get_rev_date $REV2`
    RELEASE="$REV2"
fi

# echo "PACKAGE=$PACKAGE"
# echo "REV1=$REV1"
# echo "TAG1=$TAG1"
# echo "REV2=$REV2"
# echo "TAG2=$TAG2"
# echo "DRYRUN=$DRYRUN"
# exit 1

(
    echo -n "Compiling changes from $PACKAGE tags $TAG1 to $TAG2"
    test "$DRYRUN" = no && echo -n " into $LOG"
    echo ""
) 1>&2;

gather_changes ()
{
    echo "$DATE  $ME <$EMAIL>"
    test -z "$RELEASE" || echo "	* Release $RELEASE"
    git log ${TAG1}..${TAG2} --pretty='format:	* %s' -- 2>&1
    echo ""
}

if [ "$DRYRUN" = yes ] ; then
    gather_changes
else
    mv $LOG $OLDLOG && \
    gather_changes > $LOG && \
    cat $OLDLOG >> $LOG && \
    rm $OLDLOG
fi