#!/bin/sh
######################################################################
# Copyright (C) 2006-2007 pmade inc. (Peter Jones pjones@pmade.com)
# All Rights Reserved
# 
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
# 
# 1. Redistributions of source code must retain the above copyright
#    notice, this list of conditions and the following disclaimer.
# 2. Redistributions in binary form must reproduce the above copyright
#    notice, this list of conditions and the following disclaimer in
#    the documentation and/or other materials provided with the
#    distribution.
# 3. Neither the name of the Author nor the names of its contributors
#    may be used to endorse or promote products derived from this software
#    without specific prior written permission.
# 
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS''
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
# TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
# PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR
# OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
# OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
# OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
# SUCH DAMAGE.
######################################################################

if [ $# -eq 2 ]; then
    REPOSITORY=$1
    BACKUP=$2
elif [ $# -eq 0 ]; then
    REPOSITORY=/opt/svn
    BACKUP=/opt/backup/subversion
else
    echo "Usage: svn-backup.sh [REPOSITORY BACKUP]"
    exit 1
fi

REV_FILE=$BACKUP/rev
PATH="/opt/local/bin:$PATH"

mkdir -p $BACKUP/full $BACKUP/incremental

[ -r $REV_FILE ] && REV1=`head -1 $REV_FILE`
[ x$REV1 = x ]   && REV1=0

REV2=`svnlook youngest $REPOSITORY`

if [ $REV1 -eq 0 -o `date +%u` -eq 7 ]; then
    FNAME=$BACKUP/full/`date +%Y%m%d`-R$REV2

    if [ -r $FNAME ]; then
        echo "Full svn backup exists"
        exit
    else
        echo "Doing full svn backup"
        svnadmin dump -q $REPOSITORY > $FNAME
        bzip2 $FNAME
    fi

elif [ $REV1 != $REV2 ]; then
    echo "Doing incremental backup"
    REV1=`expr $REV1 + 1`
    FNAME=$BACKUP/incremental/$REV1-$REV2
    svnadmin -q dump --incremental --revision $REV1:$REV2 $REPOSITORY > $BACKUP/incremental/$REV1-$REV2
    bzip2 $FNAME

else
    echo "No backup necessary"
    exit

fi

# update the state file
echo $REV2 > $REV_FILE

# delete backups older than 6 months
find $BACKUP/full $BACKUP/incremental -type f -mtime +186 -exec rm {} \;