adb-backup

#!/bin/bash
shopt -s extglob

# Print help and exit.
_help() {
    local path="$0";
    local script=${path##*/};
    local fmt="$(date +%Y-%m-%d)";
    cat << EOH >&2
${script}
DESCRIPTION:
  Backup data on an Android device to an Android backup '.ab' archive.
USAGE:
  ${script} [OPTIONS] <backup-name>.ab
OPTIONS:
  n, normal [default]
    Make a normal backup:
      backup everything but shared storage / SD card contents
  f, full, a, all
    Make a full backup:
      backup as much as possible,
      including shared storage / SD card contents
  q, quick, s, small
    Make a quick backup:
      do not backup apk's or shared storage / SD card contents

When the name for the backup file is not specified, it will be one of these three:
    ${fmt}.ab
    ${fmt}_full.ab
    ${fmt}_quick.ab
EOH

#'
    if [ "${1}" ]; then
        exit "${1}";
    fi;
    exit 1;
}

# Analyze user arguments.
_getopts() {
    # Declare arrays for commandline bool switches and string options.
    local -a Bools;
    local -a Strings;

    # Iterate over user arguments.
    local -i i;
    local flag;
    for ((i=1;i<=$#;i++)); do
        eval flag="\$$i";
        case "${flag}" in 
            #*(-)[hH] | *(-)[hH][eE][lL][pP] )
            *(-)[hH]*([eE][lL][pP]) )
                _help;
                ;;
            *(-)[aA]*([lL]) )
                Bools[0]=0;
                ;;
            *(-)[fF]*([uU]+([lL])) )
                Bools[0]=0;
                ;;
            *(-)[qQ]*([uU][iI][cC][kK]) )
                Bools[1]=0;
                ;;
            *(-)[sS]*([mM][aA]+([lL])) )
                Bools[1]=0;
                ;;
            *(-)[lL]*([iI][mM][iI]+([tT])*([eE][dD])) )
                Bools[1]=0;
                ;;
            * )
                Strings+=( "${flag}" );
                ;;
        esac;
    done;
    
    # Set bool options.
    DO_FULL="${Bools[0]}";
    DO_QUICK="${Bools[1]}";

    # Set string options.
    _evalopts "${Strings[*]}";
}

# Further analyze user arguments.
_evalopts() {
    if [ "$*" ]; then
        AB="$*";
        if ! _hasExt "${AB}" "ab"; then
            AB="${AB}.ab";
        fi;
        return 0;
    fi;

    if [ "${DO_FULL}" ]; then
        AB="$(date +%Y-%m-%d)_full.ab";
    elif [ "${DO_QUICK}" ]; then
        AB="$(date +%Y-%m-%d)_quick.ab";
    else
        AB="$(date +%Y-%m-%d).ab";
    fi;
}

# Echo a command, and then evaluate it.
_evalcho() {
    echo "$@";
    eval "$@";
}

# Exit with error 1 if the previous command returned an error.
_err() {
    if [[ $? == 0 ]]; then
        return 0;
    fi;

    local err="$*";
    if ! [ "${err}" ]; then
        err="An error occurred. Cannot continue.";
    fi;
    echo "${err}";
    exit 1;
}

# Run a command silently.
_q() {
    eval "$@" >&/dev/null;
}

# Remove an extension from a filename.
_rmExt() {
    local file="${1}";
    local ext="${2}";
    if [[ "${file:$((${#file}-1)):1}" == "." ]]; then
        file="$(_rmExt "${file}" "")";
    fi;

    if [[ "${file%\.${ext}*}" != "${file}" ]]; then
        echo "${file%\.${ext}*}";
    else
        echo "${file%${ext}*}";
    fi;
}

# Check whether a file ends with a certain extension.
_hasExt() {
    local file="${1}";
    local ext="${2}";
    
    # If globbing works, the file ends with the extension.
    if [[ "${file}" != "${file%%\.${ext}*}" ]]; then
        return 0;
    fi;
    return 1;
}

# Wait for Android device to connect.
_connect() {
    local connected;
    connected="$(adb devices | head -2 | tail -1)";
    if [ "${connected}" ]; then
        return 0;
    fi;
    echo "Waiting for Android device to connect...";
    adb wait-for-device;
}

# Run `adb backup` to backup an Android device.
# Backup everything EXCEPT shared storage (SD card contents).
_backup() {
    local ab="${1}";
    if ! [ "${ab}" ]; then
        ab="$(date +%Y-%m-%d).ab";
    elif ! _hasExt "${ab}" "ab"; then
        ab="${ab}.ab";
    fi;
	
    _connect;
    _evalcho adb backup -f "${ab}" -apk -obb -noshared -all -system &&
        echo "${ab}";
}

# Run `adb backup` to backup an Android device.
# Backup everything INCLUDING shared storage (SD card contents).
_backupFull() {
    local ab="${1}";
    if ! [ "${ab}" ]; then
        ab="$(date +%Y-%m-%d).ab";
    elif ! _hasExt "${ab}" "ab"; then
        ab="${ab}.ab";
    fi;
	
    _connect;
    _evalcho adb backup -f "${ab}" -apk -obb -shared -all -system &&
        echo "${ab}";
}

# Run `adb backup` to backup an Android device.
# Do not backup apks.
_backupQuick() {
    local ab="${1}";
    if ! [ "${ab}" ]; then
        ab="$(date +%Y-%m-%d).ab";
    elif ! _hasExt "${ab}" "ab"; then
        ab="${ab}.ab";
    fi;
	
    _connect;
    #_evalcho adb backup -f "${ab}" -noapk -noobb -noshared -all -system;
    _evalcho adb backup -f "${ab}" -noapk -noobb -noshared -all &&
        echo "${ab}";
    
}

# Declare bool variables.
declare DO_FULL;
declare DO_QUICK;

# Declare string variables.
declare AB;

# Evaluate user arguments.
_getopts "$@";
_evalopts;

# Backup Android device.
if [ "${DO_FULL}" ]; then
    _backupFull "${AB}";
elif [ "${DO_QUICK}" ]; then
    _backupQuick "${AB}";
else
    _backup "${AB}";
fi;