#!/bin/bash
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.

# Unpack a disk image to a specified target folder
#
# Usage: unpack-diskimage <image_file>
#                         <mountpoint>
#                         <target_path>

DMG_PATH=$1
MOUNTPOINT=$2
TARGETPATH=$3

# How long to wait before giving up waiting for the mount to finish (seconds)
TIMEOUT=90

# If mnt already exists, then the previous run may not have cleaned up
# properly.  We should try to umount and remove the mnt directory.
if [ -d $MOUNTPOINT ]; then
    echo "mnt already exists, trying to clean up"
    hdiutil detach $MOUNTPOINT -force
    rm -rdfv $MOUNTPOINT
fi

# Install an on-exit handler that will unmount and remove the '$MOUNTPOINT' directory
trap "{ if [ -d $MOUNTPOINT ]; then hdiutil detach $MOUNTPOINT -force; rm -rdfv $MOUNTPOINT; fi; }" EXIT

mkdir -p $MOUNTPOINT

hdiutil attach -verbose -noautoopen -mountpoint $MOUNTPOINT "$DMG_PATH"
# Wait for files to show up
# hdiutil uses a helper process, diskimages-helper, which isn't always done its
# work by the time hdiutil exits. So we wait until something shows up in the
# mnt directory. Due to the async nature of diskimages-helper, the best thing
# we can do is to make sure the glob() rsync is making can find files.
i=0
while [ "$(echo $MOUNTPOINT/*)" == "$MOUNTPOINT/*" ]; do
    if [ $i -gt $TIMEOUT ]; then
        echo "No files found, exiting"
        exit 1
    fi
    sleep 1
    i=$(expr $i + 1)
done
# Now we can copy everything out of the $MOUNTPOINT directory into the target directory
rsync -av $MOUNTPOINT/* $MOUNTPOINT/.DS_Store $MOUNTPOINT/.background $MOUNTPOINT/.VolumeIcon.icns $TARGETPATH/.
hdiutil detach $MOUNTPOINT
rm -rdf $MOUNTPOINT
# diskimage-helper prints messages to stdout asynchronously as well, sleep
# for a bit to ensure they don't disturb following commands in a script that
# might parse stdout messages
sleep 5