codekingpro/portable-devtools

1# Protocol Buffers - Google's data interchange format2# Copyright 2008 Google Inc.  All rights reserved.3#4# Use of this source code is governed by a BSD-style5# license that can be found in the LICENSE file or at6# https://developers.google.com/open-source/licenses/bsd7 8"""Contains _ExtensionDict class to represent extensions.9"""10 11from google.protobuf.internal import type_checkers12from google.protobuf.descriptor import FieldDescriptor13 14 15def _VerifyExtensionHandle(message, extension_handle):16  """Verify that the given extension handle is valid."""17 18  if not isinstance(extension_handle, FieldDescriptor):19    raise KeyError('HasExtension() expects an extension handle, got: %s' %20                   extension_handle)21 22  if not extension_handle.is_extension:23    raise KeyError('"%s" is not an extension.' % extension_handle.full_name)24 25  if not extension_handle.containing_type:26    raise KeyError('"%s" is missing a containing_type.'27                   % extension_handle.full_name)28 29  if extension_handle.containing_type is not message.DESCRIPTOR:30    raise KeyError('Extension "%s" extends message type "%s", but this '31                   'message is of type "%s".' %32                   (extension_handle.full_name,33                    extension_handle.containing_type.full_name,34                    message.DESCRIPTOR.full_name))35 36 37# TODO: Unify error handling of "unknown extension" crap.38# TODO: Support iteritems()-style iteration over all39# extensions with the "has" bits turned on?40class _ExtensionDict(object):41 42  """Dict-like container for Extension fields on proto instances.43 44  Note that in all cases we expect extension handles to be45  FieldDescriptors.46  """47 48  def __init__(self, extended_message):49    """50    Args:51      extended_message: Message instance for which we are the Extensions dict.52    """53    self._extended_message = extended_message54 55  def __getitem__(self, extension_handle):56    """Returns the current value of the given extension handle."""57 58    _VerifyExtensionHandle(self._extended_message, extension_handle)59 60    result = self._extended_message._fields.get(extension_handle)61    if result is not None:62      return result63 64    if extension_handle.is_repeated:65      result = extension_handle._default_constructor(self._extended_message)66    elif extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE:67      message_type = extension_handle.message_type68      if not hasattr(message_type, '_concrete_class'):69        # pylint: disable=g-import-not-at-top70        from google.protobuf import message_factory71        message_factory.GetMessageClass(message_type)72      if not hasattr(extension_handle.message_type, '_concrete_class'):73        from google.protobuf import message_factory74        message_factory.GetMessageClass(extension_handle.message_type)75      result = extension_handle.message_type._concrete_class()76      try:77        result._SetListener(self._extended_message._listener_for_children)78      except ReferenceError:79        pass80    else:81      # Singular scalar -- just return the default without inserting into the82      # dict.83      return extension_handle.default_value84 85    # Atomically check if another thread has preempted us and, if not, swap86    # in the new object we just created.  If someone has preempted us, we87    # take that object and discard ours.88    # WARNING:  We are relying on setdefault() being atomic.  This is true89    #   in CPython but we haven't investigated others.  This warning appears90    #   in several other locations in this file.91    result = self._extended_message._fields.setdefault(92        extension_handle, result)93 94    return result95 96  def __eq__(self, other):97    if not isinstance(other, self.__class__):98      return False99 100    my_fields = self._extended_message.ListFields()101    other_fields = other._extended_message.ListFields()102 103    # Get rid of non-extension fields.104    my_fields = [field for field in my_fields if field.is_extension]105    other_fields = [field for field in other_fields if field.is_extension]106 107    return my_fields == other_fields108 109  def __ne__(self, other):110    return not self == other111 112  def __len__(self):113    fields = self._extended_message.ListFields()114    # Get rid of non-extension fields.115    extension_fields = [field for field in fields if field[0].is_extension]116    return len(extension_fields)117 118  def __hash__(self):119    raise TypeError('unhashable object')120 121  # Note that this is only meaningful for non-repeated, scalar extension122  # fields.  Note also that we may have to call _Modified() when we do123  # successfully set a field this way, to set any necessary "has" bits in the124  # ancestors of the extended message.125  def __setitem__(self, extension_handle, value):126    """If extension_handle specifies a non-repeated, scalar extension127    field, sets the value of that field.128    """129 130    _VerifyExtensionHandle(self._extended_message, extension_handle)131 132    if (extension_handle.is_repeated or133        extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE):134      raise TypeError(135          'Cannot assign to extension "%s" because it is a repeated or '136          'composite type.' % extension_handle.full_name)137 138    # It's slightly wasteful to lookup the type checker each time,139    # but we expect this to be a vanishingly uncommon case anyway.140    type_checker = type_checkers.GetTypeChecker(extension_handle)141    # pylint: disable=protected-access142    self._extended_message._fields[extension_handle] = (143        type_checker.CheckValue(value))144    self._extended_message._Modified()145 146  def __delitem__(self, extension_handle):147    self._extended_message.ClearExtension(extension_handle)148 149  def _FindExtensionByName(self, name):150    """Tries to find a known extension with the specified name.151 152    Args:153      name: Extension full name.154 155    Returns:156      Extension field descriptor.157    """158    descriptor = self._extended_message.DESCRIPTOR159    extensions = descriptor.file.pool._extensions_by_name[descriptor]160    return extensions.get(name, None)161 162  def _FindExtensionByNumber(self, number):163    """Tries to find a known extension with the field number.164 165    Args:166      number: Extension field number.167 168    Returns:169      Extension field descriptor.170    """171    descriptor = self._extended_message.DESCRIPTOR172    extensions = descriptor.file.pool._extensions_by_number[descriptor]173    return extensions.get(number, None)174 175  def __iter__(self):176    # Return a generator over the populated extension fields177    return (f[0] for f in self._extended_message.ListFields()178            if f[0].is_extension)179 180  def __contains__(self, extension_handle):181    _VerifyExtensionHandle(self._extended_message, extension_handle)182 183    if extension_handle not in self._extended_message._fields:184      return False185 186    if extension_handle.is_repeated:187      return bool(self._extended_message._fields.get(extension_handle))188 189    if extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE:190      value = self._extended_message._fields.get(extension_handle)191      # pylint: disable=protected-access192      return value is not None and value._is_present_in_parent193 194    return True195