1 # Copyright 2013 The Chromium Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 6 class SystemProperties(dict): 7 8 """A dict interface to interact with device system properties. 9 10 System properties are key/value pairs as exposed by adb shell getprop/setprop. 11 12 This implementation minimizes interaction with the physical device. It is 13 valid for the lifetime of a boot. 14 """ 15 16 def __init__(self, android_commands): 17 super(SystemProperties, self).__init__() 18 self._adb = android_commands 19 self._cached_static_properties = {} 20 21 def __getitem__(self, key): 22 if self._IsStatic(key): 23 if key not in self._cached_static_properties: 24 self._cached_static_properties[key] = self._GetProperty(key) 25 return self._cached_static_properties[key] 26 return self._GetProperty(key) 27 28 def __setitem__(self, key, value): 29 # TODO(tonyg): This can fail with no root. Verify that it succeeds. 30 self._adb.SendShellCommand('setprop %s "%s"' % (key, value), retry_count=3) 31 32 @staticmethod 33 def _IsStatic(key): 34 # TODO(tonyg): This list is conservative and could be expanded as needed. 35 return (key.startswith('ro.boot.') or 36 key.startswith('ro.build.') or 37 key.startswith('ro.product.')) 38 39 def _GetProperty(self, key): 40 return self._adb.SendShellCommand('getprop %s' % key, retry_count=3).strip() 41
