#!/bin/sh

##
# Make a disk image v1.0
#
# Wilfredo Sanchez, wsanchez@mit.edu
# Copyright (c) 2002 Wilfredo Sanchez. All rights reserved.
##

set -u
set -e

usage()
{
    echo "$(basename $0): usage: $(basename $0) target source"
    echo "	target specifies target volume name and image name"
    echo "	source specifies source directory to place at root of volume"
    echo "	Do not include .dmg extention in target"
    exit 1
}

if [ $# != 0 ]; then Target=$1 && shift; else usage; fi
if [ $# != 0 ]; then Source=$1 && shift; else usage; fi

if [ $# != 0 ]; then usage; fi

if [ -e "${Target}.dmg" ]; then
    echo "${Target}.dmg exists."
    exit 1
fi

# Get a unique temporary image file
TempImage="/tmp/make_image_dmg.$$"
while [ -e "${TempImage}.dmg" ]; do TempImage="${TempImage}x"; done
TempImage="${TempImage}.dmg"

# Get size in MB of the source directory, add 4
Size=$(($(du -s "${Source}" | cut -f 1) / 1024 + 4))

# Create a disk image of the right size
hdiutil create -megabytes "${Size}" -layout NONE "${TempImage}"

# Attach the image to a device node without mounting it
# The cut is needed because hdid spits out crap after the device name
DiskDevice=$(hdid -nomount "${TempImage}" | cut -f 1 -d ' ')

# Format the mounted volume as HFS+
newfs_hfs -v "${Target}" "${DiskDevice}"

# Get a unique temporary mount point
MountPoint="/tmp/make_image_mnt.$$"
while [ -e "${MountPoint}" ]; do MountPoint="${MountPoint}x"; done

# Mount the image
mkdir -p "${MountPoint}"
mount -t hfs "${DiskDevice}" "${MountPoint}"

# Copy data
pax -s '|'"${Source}"'||' -rw "${Source}" "${MountPoint}"

# Umount the image
umount "${DiskDevice}"
rm -rf "${MountPoint}"

# Detach the device
hdiutil eject "${DiskDevice}"

# Create a read-only version, use zlib compression
hdiutil convert -format UDZO "${TempImage}" -o "${Target}"

# Delete the temporary image
rm -f "${TempImage}"