adb_wait_for_device: More fixes

platform_tools/android/bin/adb_wait_for_device

 #!/bin/bash
 #
 # Wait for the device to be ready to run tests.
 
 SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 source $SCRIPT_DIR/android_setup.sh
 source $SCRIPT_DIR/utils/setup_adb.sh
 
-function _get_battery_level {
+# Helper function used by get_battery_level. Parses the battery level from
+# dumpsys output.
+function _parse_battery_level {
   SPLIT=( $@ )
 
   HAS_BATTERY=1
   LEVEL=""
 
   for i in "${!SPLIT[@]}"; do
     if [ "${SPLIT[$i]}" = "level:" ]; then
       LEVEL="${SPLIT[$i+1]}"
     fi
     if [ "${SPLIT[$i]}" = "present:" ]; then
       PRESENT="$(echo "${SPLIT[$i+1]}" | tr -d '\r')"
-      if [ "$PRESENT" -eq "0" ]; then
+      if [ "$PRESENT" = "0" ]; then

[borenet, 2015/12/14 18:26:24]

Prevents error if PRESENT is not an integer, eg. "true" or "false"

         HAS_BATTERY=0
       fi
       if [ "$PRESENT" = "false" ]; then
         HAS_BATTERY=0
       fi
     fi
   done
 
   if [ "$HAS_BATTERY" = "1" ]; then
     echo "$LEVEL" | tr -d '\r'
     return
   fi
   # If there's no battery, report a full battery.
   echo "Device has no battery." 1>&2
   echo "100"
 }
 
+# Echo the battery level percentage of the attached Android device.
 function get_battery_level {
   STATS="$($ADB $DEVICE_SERIAL shell dumpsys batteryproperties)"
   SPLIT=( $STATS )
-  RV="$(_get_battery_level ${SPLIT[@]})"
+  RV="$(_parse_battery_level ${SPLIT[@]})"
   if [ -n "$RV" ]; then
     echo "$RV"
     return
   fi
 
   echo "Battery level fallback..." 1>&2
 
   STATS="$($ADB $DEVICE_SERIAL shell dumpsys battery)"
   SPLIT=( $STATS )
-  RV="$(_get_battery_level ${SPLIT[@]})"
+  RV="$(_parse_battery_level ${SPLIT[@]})"
   if [ "$RV" != "-1" ]; then
     echo "$RV"
     return
   fi
 
   echo "Could not determine battery level!" 1>&2
   # Just exit to prevent hanging forever or failing the build.
   echo "0"
 }
 
 set -e
 
 # Wait for the device to be connected and fully booted.
 while [ "$($ADB $DEVICE_SERIAL shell getprop sys.boot_completed | tr -d '\r')" != "1" ]; do
   echo "Waiting for the device to be connected and ready."
   sleep 5
 done
 
 # Wait for battery charge.
 DESIRED_BATTERY_LEVEL=30
 CURRENT_BATTERY_LEVEL="$(get_battery_level)"
 while [ "${CURRENT_BATTERY_LEVEL}" -lt "${DESIRED_BATTERY_LEVEL}" ]; do
   echo "Battery level is ${CURRENT_BATTERY_LEVEL}; waiting to charge to ${DESIRED_BATTERY_LEVEL}"
   sleep 5
   CURRENT_BATTERY_LEVEL="$(get_battery_level)"
 done
 
 echo "Ready!"