Cleanup machine based on the state in configuration file for mini installer test.

chrome/test/mini_installer/cleanup.py

+# Copyright 2017 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.
+
+import _winreg
+import os
+import shutil
+
+import file_verifier
+import registry_verifier
+import verifier_runner
+
+class FileCleaner(file_verifier.FileVerifier):
+  """ Delete the directory if it exists but marked as shouldn't exist
+      in the config file.
+  """
+  def _Assert(self, is_true, message):
+    """ Override verifyer.Verifier._Assert
+    """
+    if not is_true and self._file_exists and os.path.isdir(self._file_path):
+      shutil.rmtree(self._file_path, ignore_errors=True)
+
+class RegistryCleaner(registry_verifier.RegistryVerifier):
+  """ Delete the registry key recursively if it exists and marked as forbidden
+      in the config file.
+  """
+  def _DeleteRegKey(self, root, key_path):
+    """ Delete a registry key recursively.
+
+        Args:
+          root: An integer represents HKEY_ constant.
+          key_path: A string represents the path of key that needs to be
+                    deleted.
+    """
+    with _winreg.OpenKey(root, key_path, 0, _winreg.KEY_SET_VALUE |
+                                            _winreg.KEY_READ |
+                                            _winreg.KEY_WOW64_32KEY) as key:
+      num_of_sub_keys, _, _ =  _winreg.QueryInfoKey(key)
+      for i in range(0, num_of_sub_keys):
+        self._DeleteRegKey(root, key_path + "\\" + _winreg.EnumKey(key, i))
+    _winreg.DeleteKey(root, key_path)
+
+
+  def _Assert(self, is_true, message):
+    """ Override verifyer.Verifier._Assert
+    """
+    if not is_true and self._is_key_forbidden:
+      try:
+        self._DeleteRegKey(self._root_key_value, self._sub_key)
+      except WindowsError:
+        # Suppress any delete error
+        pass
+
+class CleanupRunner:
+  """ Run cleaners based on the config state.
+  """
+  _instance = None
+
+  def __init__(self):
+    self._cleaners = {
+      verifier_runner.FILES: FileCleaner(),
+      verifier_runner.REGISTRY_ENTRIES: RegistryCleaner(),
+    }
+
+  @classmethod
+  def Create(cls):
+    """Singleton constructor.
+    """
+    if not cls._instance:
+      cls._instance = CleanupRunner()
+    return cls._instance
+
+  def CleanAll(self, state, variable_expander):
+    """ Put the machine to a clean state based on the config file.
+
+        Only support:
+          1) Delete directory, always recursively. Delete file is NOT supported.
+          2) Delete registry key, always recursively.
+        Args:
+          state: A property dictionary reprsents the clean state in the
+                    config file.
+          variable_expander: A VariableExpander object.
+    """
+    for verifier_name, verifier_input in state.iteritems():
+      if verifier_name not in self._cleaners:
+        continue
+      self._cleaners[verifier_name].VerifyInput(verifier_input,

[grt (UTC plus 2), 2017/03/14 09:19:44]

rather than using a Verifier to do the cleaning, i think it's more elegant to
turn walking a state's property dict into something more like a proper Visitor
pattern. verification would look sorta like:

// Traverse a state's property dict, invoking |visitor|'s
// "VisitPropertyName" methods along the way.
WalkPropertyDict(visitor):
  for each (name, input) in property dict:
    // invoke the visitor's "VisitFooBar" method
    getattr(visitor, 'Visit' + name)(input, expander)

// A visitor for state property dict walking that verifies the state.
VerifierVisitor:
  VisitFiles:
    self.file_verifier.VerifyInput
  VisitProcesses:
    self.process_verifier.VerifyInput
  VisitRegistryEntries:
    self.registry_verifier.VerifyInput

VerifyAll:
  WalkPropertyDict(new VerifierVisitor)

and then cleaning would look like:

// A visitor for state property dict walking that cleans to make the state
valid.
CleanerVisitor:
  VisitFiles:
    self.file_cleaner.CleanInput
  VisitProcesses:
    self.process_cleaner.CleanInput
  VisitRegistryEntries:
    self.registry_cleaner.CleanInput

CleanAll:
  WalkPropertyDict(new CleanerVisitor)

[zmin, 2017/03/14 23:13:00]

Ok, I'll refactor the code.

+                                                 variable_expander)