old_contents: # Copyright 2013 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.
  
  """A temp file that automatically gets pushed and deleted from a device."""
  
  # pylint: disable=W0622
  
  import random
  import time
  
  from pylib import cmd_helper
  from pylib.device import device_errors
  
  
  class DeviceTempFile(object):
    def __init__(self, adb, suffix='', prefix='temp_file', dir='/data/local/tmp'):
      """Find an unused temporary file path in the devices external directory.
  
      When this object is closed, the file will be deleted on the device.
  
      Args:
        adb: An instance of AdbWrapper
        suffix: The suffix of the name of the temp file.
        prefix: The prefix of the name of the temp file.
        dir: The directory on the device where to place the temp file.
      """
      self._adb = adb
      # make sure that the temp dir is writable
      self._adb.Shell('test -d %s' % cmd_helper.SingleQuote(dir))
      while True:
        self.name = '{dir}/{prefix}-{time:d}-{nonce:d}{suffix}'.format(
          dir=dir, prefix=prefix, time=int(time.time()),
          nonce=random.randint(0, 1000000), suffix=suffix)
        self.name_quoted = cmd_helper.SingleQuote(self.name)
        try:
          self._adb.Shell('test -e %s' % self.name_quoted)
        except device_errors.AdbCommandFailedError:
          break # file does not exist
  
      # Immediately touch the file, so other temp files can't get the same name.
      self._adb.Shell('touch %s' % self.name_quoted)
  
    def close(self):
      """Deletes the temporary file from the device."""
      # ignore exception if the file is already gone.
      try:
        self._adb.Shell('rm -f %s' % self.name_quoted)
      except device_errors.AdbCommandFailedError:
        # file does not exist on Android version without 'rm -f' support (ICS)
        pass
  
    def __enter__(self):
      return self
  
    def __exit__(self, type, value, traceback):
      self.close()
  
new_contents: # Copyright 2013 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.
  
  """A temp file that automatically gets pushed and deleted from a device."""
  
  # pylint: disable=W0622
  
  from pylib import cmd_helper
  from pylib.device import device_errors
  
  _COMMAND_TEMPLATE = (
      # Make sure that the temp dir is writable
      'test -d {dir} && '
      # If 10 random attempts fail, something is up.
      'for i in $(seq 10); do '
      'fn={dir}/{prefix}-$(date +%s)-"$RANDOM"{suffix};'
      'test -e "$fn" || break;'
      'done && '
      # Touch the file, so other temp files can't get the same name.
      'touch "$fn" && echo -n "$fn"')
  
  class DeviceTempFile(object):
    def __init__(self, adb, suffix='', prefix='temp_file', dir='/data/local/tmp'):
      """Find an unused temporary file path in the devices external directory.
  
      When this object is closed, the file will be deleted on the device.
  
      Args:
        adb: An instance of AdbWrapper
        suffix: The suffix of the name of the temp file.
        prefix: The prefix of the name of the temp file.
        dir: The directory on the device where to place the temp file.
      """
      self._adb = adb
      command = _COMMAND_TEMPLATE.format(
          dir=cmd_helper.SingleQuote(dir),
          suffix=cmd_helper.SingleQuote(suffix),
          prefix=cmd_helper.SingleQuote(prefix))
      self.name = self._adb.Shell(command)
      self.name_quoted = cmd_helper.SingleQuote(self.name)
  
    def close(self):
      """Deletes the temporary file from the device."""
      # ignore exception if the file is already gone.
      try:
        self._adb.Shell('rm -f %s' % self.name_quoted)
      except device_errors.AdbCommandFailedError:
        # file does not exist on Android version without 'rm -f' support (ICS)
        pass
  
    def __enter__(self):
      return self
  
    def __exit__(self, type, value, traceback):
      self.close()
  
subject: Optimize DeviceTempFile() by combining logic into a single "adb shell"