Adding battery control API for android.

build/android/pylib/android_commands.py

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Provides an interface to communicate with the device via the adb command.
 
 Assumes adb binary is currently on system path.
 """
 # pylint: disable-all
 
@@ skipping 55 matching lines @@
 KEYCODE_DPAD_UP = 19
 KEYCODE_DPAD_DOWN = 20
 KEYCODE_DPAD_RIGHT = 22
 KEYCODE_ENTER = 66
 KEYCODE_MENU = 82
 
 MD5SUM_DEVICE_FOLDER = constants.TEST_EXECUTABLE_DIR + '/md5sum/'
 MD5SUM_DEVICE_PATH = MD5SUM_DEVICE_FOLDER + 'md5sum_bin'
 MD5SUM_LD_LIBRARY_PATH = 'LD_LIBRARY_PATH=%s' % MD5SUM_DEVICE_FOLDER
 
+CONTROL_BATTERY_CHARGING_COMMAND = [

[Philippe, 2014/04/01 09:51:58]

Nit: s/COMMAND/COMMANDS?

[qsr, 2014/04/02 09:14:57]

Done.

+  {

[tonyg, 2014/04/01 16:13:18]

WDYT about adding a comment listing some example devices that support each dict
in this list? I'm mostly just curious which device has the pm8921.

[qsr, 2014/04/02 09:14:57]

 Done. This one if for the N4 and the only one I have worked with for now.

+    'witness_file': '/sys/module/pm8921_charger/parameters/disabled',
+    'enable_command': 'echo 0 > /sys/module/pm8921_charger/parameters/disabled',
+    'disable_command':
+        'echo 1 > /sys/module/pm8921_charger/parameters/disabled',
+  },
+];
 
 def GetAVDs():
   """Returns a list of AVDs."""
   re_avd = re.compile('^[ ]+Name: ([a-zA-Z0-9_:.-]+)', re.MULTILINE)
   avds = re_avd.findall(cmd_helper.GetCmdOutput(['android', 'list', 'avd']))
   return avds
 
 def ResetBadDevices():
   """Removes the blacklist that keeps track of bad devices for a current
      build.
@@ skipping 1732 matching lines @@
     out = self.RunShellCommand('sh %s %s %s' % (temp_script_file, source, dest),
                                timeout_time=120)
     if self._device:
       device_repr = self._device[-4:]
     else:
       device_repr = '????'
     for line in out:
       logging.info('[%s]> %s', device_repr, line)
     self.RunShellCommand('rm %s' % temp_script_file)
 
+  def _GetControlBatteryChargingCommand(self):
+    for command in CONTROL_BATTERY_CHARGING_COMMAND:
+      witness_file = command['witness_file']
+      if self.FileExistsOnDevice(witness_file):

[tonyg, 2014/04/01 16:13:18]

Maybe we should add an assert that all of the required fields (enable_command,
disable_command) are present in the dict.

[qsr, 2014/04/02 09:14:57]

Done.

+        return command
+    return None
+
+  def CanControlBatteryCharging(self):

[tonyg, 2014/04/01 16:13:18]

Is BatteryCharging really the intent of this API? Because one thing is disabling
battery charging, but that isn't that useful to us if the system is still
drawing power from USB. Hopefully the intent is CanControlUsbCharging. If so,
let's rename. If not, I'm curious about the motivation.

[qsr, 2014/04/02 09:14:57]

 You are right. Will rename.

+    return self._GetControlBatteryChargingCommand() is not None
+
+  def DisableBatteryCharging(self):
+    command = self._GetControlBatteryChargingCommand()

[tonyg, 2014/04/01 16:13:18]

Can we cache the enable/disable command in _GetControlBatteryChargingCommand().
That way we don't have to round trip to the device to keep looking if files
exist.

[qsr, 2014/04/02 09:14:57]

Done.

+    if not command:
+      raise Exception('Unable to act on battery charing.')

[tonyg, 2014/04/01 16:13:18]

s/charing/charging/

[qsr, 2014/04/02 09:14:57]

Done.

+    disable_command = command['disable_command']
+    self.RunShellCommand(disable_command)
+
+  def EnableBatteryCharging(self):
+    command = self._GetControlBatteryChargingCommand()
+    if not command:
+      raise Exception('Unable to act on battery charing.')
+    disable_command = command['enable_command']
+    self.RunShellCommand(disable_command)
+
 
 class NewLineNormalizer(object):
   """A file-like object to normalize EOLs to '\n'.
 
   Pexpect runs adb within a pseudo-tty device (see
   http://www.noah.org/wiki/pexpect), so any '\n' printed by adb is written
   as '\r\n' to the logfile. Since adb already uses '\r\n' to terminate
   lines, the log ends up having '\r\r\n' at the end of each line. This
   filter replaces the above with a single '\n' in the data stream.
   """
   def __init__(self, output):
     self._output = output
 
   def write(self, data):
     data = data.replace('\r\r\n', '\n')
     self._output.write(data)
 
   def flush(self):
     self._output.flush()