#!/bin/bash
#
#   pacman-optimize
#   @configure_input@
#
#   Copyright (c) 2002-2007 by Judd Vinet <jvinet@zeroflux.org>
#
#   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.
#

# gettext initialization
export TEXTDOMAIN='pacman'
export TEXTDOMAINDIR='@localedir@'

myver='@PACKAGE_VERSION@'
dbroot='@localstatedir@/lib/pacman/'
lockfile="${dbroot}db.lck"

msg() {
	local mesg=$1; shift
	printf "==> ${mesg}\n" "$@" >&2
}

error () {
	local mesg=$1; shift
	printf "==> ERROR: ${mesg}\n" "$@" >&2
}

usage() {
	printf "pacman-optimize (pacman) %s\n" "$myver"
	echo
	printf "$(gettext "Usage: %s[pacman_db_root]")\n" "$0"
	echo
	echo "$(gettext "pacman-optimize is a little hack that should improve the performance")"
	echo "$(gettext "of pacman when reading/writing to its filesystem-based database.")"
	echo
	echo "$(gettext "Because pacman uses many small files to keep track of packages,")"
	echo "$(gettext "there is a tendency for these files to become fragmented over time.")"
	echo "$(gettext "This script attempts to relocate these small files into one")"
	echo "$(gettext "continuous location on your hard drive. The result is that the hard")"
	echo "$(gettext "drive should be able to read them faster, since the hard drive head")"
	echo "$(gettext "does not have to move around the disk as much.")"
	echo
}

version() {
	printf "pacman-optimize (pacman) %s\n" "$myver"
	printf "Copyright (C) 2002-2007 Judd Vinet <jvinet@zeroflux.org>.\n"
	echo
	printf "This is free software; see the source for copying conditions.\n"
	printf "There is NO WARRANTY, to the extent permitted by law.\n"
	echo
}

die() {
	error $@
	exit 1
}

die_r() {
	rm -f $lockfile
	die $@
}

if [ "$1" = "-h" -o "$1" = "--help" ]; then
	usage
	exit 0
fi

if [ "$1" = "-V" -o "$1" = "--version" ]; then
	version
	exit 0
fi

if [ "$1" != "" ]; then
	dbroot="$1"
fi

# make sure pacman isn't running
if [ -f $lockfile ]; then
	die "$(gettext "Pacman lockfile was found. Cannot run while pacman is running.")"
fi

if [ ! -d "$dbroot" ]; then
	die "$(gettext "%s does not exist or is not a directory.")" "$dbroot"
fi

if [ ! -w "$dbroot" ]; then
	die "$(gettext "You must have correct permissions to optimize the database.")"
fi

# do not let pacman run while we do this
touch $lockfile

# step 1: sum the old db
msg "$(gettext "MD5sum'ing the old database...")"
find $dbroot -type f | sort | xargs md5sum > /tmp/pacsums.old

# step 2: tar it up
msg "$(gettext "Tar'ing up %s...")" "$dbroot"
cd $dbroot
tar -czf /tmp/pacmanDB.tgz ./
if [ $? -ne 0 ]; then
	rm -f /tmp/pacmanDB.tgz /tmp/pacsums.old
	die_r "$(gettext "Tar'ing up %s failed.")" "$dbroot"
fi

# step 3: make and sum the new db
msg "$(gettext "Making and MD5sum'ing the new db...")"
mkdir $dbroot.new
tar -zxpf /tmp/pacmanDB.tgz -C $dbroot.new/
if [ $? -ne 0 ]; then
       rm -f /tmp/pacmanDB.tgz /tmp/pacsums.old
       rm -rf "$dbroot.new"
       die_r "$(gettext "Untar'ing $dbroot failed.")"
fi
find "$dbroot.new" -type f | sort | sed -e 's/pacman.new/pacman/g' | \
		xargs md5sum > /tmp/pacsums.new

# step 4: compare the sums
msg "$(gettext "Checking integrity...")"
diff /tmp/pacsums.old /tmp/pacsums.new >/dev/null 2>&1
if [ $? -ne 0 ]; then
	# failed
	# leave /tmp/pacsums.old and .new for checking to see what doesn't match up
	rm -rf "$dbroot.new" $lockfile /tmp/pacmanDB.tgz
	die_r "$(gettext "integrity check FAILED, reverting to old database.")"
fi

# step 5: remove the new temporary database and the old one
#         and use the .tgz to replace the old one
msg "$(gettext "Putting the new database in place...")"
rm -rf "$dbroot.new" "$dbroot"/*
tar -zxpf /tmp/pacmanDB.tgz -C "$dbroot"/

# remove the lock file, sum files, and .tgz of database
rm -f $lockfile /tmp/pacsums.old /tmp/pacsums.new /tmp/pacmanDB.tgz

echo
echo "$(gettext "Finished. Your pacman database has been optimized.")"
echo

exit 0

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