From 9a95d9999343026480b6bf934ac31954a64f93de Mon Sep 17 00:00:00 2001
From: Aaron Ball <nullspoon@oper.io>
Date: Sat, 14 Oct 2017 18:37:11 -0600
Subject: Rewrote the package setup and compression process

Previously, the packaging process created a working directory in which
modifications could be made before the final tarball creation. This was
problematic because most of the time, the backup destination is on a
vfat filesystem, which doesn't support symlinks. Any packages that used
symlinks in their data directory would through "Function not
implemented" errors during the initial copy of this directory. There
were also space concerns with this approach.

This updates the package process to construct a tar command. The
constructon of this command is where package modifications can be made
(eg: --exclude).  The usage of tar directly on the source files removes
the need to copy files around. This uses much less storage as well as
performs much faster as it is now almost entirely done in memory.
---
 andbackup.sh | 20 +++++++++-----------
 1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/andbackup.sh b/andbackup.sh
index 7f5c239..72b8aac 100755
--- a/andbackup.sh
+++ b/andbackup.sh
@@ -85,7 +85,10 @@ lfatal() {
 backup_app() {
   local app="${1}"
 
-  if [ -z "${app}" ]; then
+  local tar  # Tar command for packaging the backup
+
+  # Make sure app is specified
+  if [[ -z ${app} ]]; then
     lerror "Application name required."
     return 1
   fi
@@ -115,8 +118,6 @@ backup_app() {
 
   # Create backup destination if not exist
   [ ! -d "${backups}" ] && mkdir -p "${backups}"
-  # Delete data stage directory if it exists so we can start new
-  [ -d "${backups}/${app}/data" ] && rm -rf "${backups}/${app}/data"
 
   # Backup the apk file if it exists
   if [ ! -z "${apk}" ]; then
@@ -150,24 +151,21 @@ backup_app() {
     linfo "Skipping application force stop while booted to recovery mode."
   fi
 
-  # Copy the user data
-  cp -rp "${data}" "${backups}/${app}/data"
+  tar="tar -C ${data} -c "
   # Delete cache directory if it exists
   # This will sometimes free up significant amounts of space
-  if [ ! -d "${backups}/${app}/data/cache" ]; then
+  if [[ ! -d "${data}/cache" ]]; then
     linfo "Cache doesn't exist for ${app}"
   elif ! $preserveCache; then
-    linfo "Deleting cache for ${app}"
-    rm -rf "${backups}/${app}/data/cache"
+    linfo "Excluding cache for ${app}"
+    tar="${tar} --exclude=cache"
   else
     linfo "Preserving cache for ${app}"
   fi
 
   # Compress the backup
   linfo "Compressing userdata for ${app}"
-  cd "${backups}/${app}/"
-  tar -c data | gzip -c > data.tar.gz
-  rm -rf data
+  ${tar} . | gzip -c > "${backups}/${app}/data.tar.gz"
 }
 
 
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