Edit File: extension_dict.py
# Protocol Buffers - Google's data interchange format # Copyright 2008 Google Inc. All rights reserved. # https://developers.google.com/protocol-buffers/ # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions are # met: # # * Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # * Redistributions in binary form must reproduce the above # copyright notice, this list of conditions and the following disclaimer # in the documentation and/or other materials provided with the # distribution. # * Neither the name of Google Inc. nor the names of its # contributors may be used to endorse or promote products derived from # this software without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR # A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT # OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, # DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY # THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """Contains _ExtensionDict class to represent extensions. """ from google.protobuf.internal import type_checkers from google.protobuf.descriptor import FieldDescriptor def _VerifyExtensionHandle(message, extension_handle): """Verify that the given extension handle is valid.""" if not isinstance(extension_handle, FieldDescriptor): raise KeyError('HasExtension() expects an extension handle, got: %s' % extension_handle) if not extension_handle.is_extension: raise KeyError('"%s" is not an extension.' % extension_handle.full_name) if not extension_handle.containing_type: raise KeyError('"%s" is missing a containing_type.' % extension_handle.full_name) if extension_handle.containing_type is not message.DESCRIPTOR: raise KeyError('Extension "%s" extends message type "%s", but this ' 'message is of type "%s".' % (extension_handle.full_name, extension_handle.containing_type.full_name, message.DESCRIPTOR.full_name)) # TODO(robinson): Unify error handling of "unknown extension" crap. # TODO(robinson): Support iteritems()-style iteration over all # extensions with the "has" bits turned on? class _ExtensionDict(object): """Dict-like container for Extension fields on proto instances. Note that in all cases we expect extension handles to be FieldDescriptors. """ def __init__(self, extended_message): """ Args: extended_message: Message instance for which we are the Extensions dict. """ self._extended_message = extended_message def __getitem__(self, extension_handle): """Returns the current value of the given extension handle.""" _VerifyExtensionHandle(self._extended_message, extension_handle) result = self._extended_message._fields.get(extension_handle) if result is not None: return result if extension_handle.label == FieldDescriptor.LABEL_REPEATED: result = extension_handle._default_constructor(self._extended_message) elif extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE: message_type = extension_handle.message_type if not hasattr(message_type, '_concrete_class'): # pylint: disable=g-import-not-at-top from google.protobuf import message_factory message_factory.GetMessageClass(message_type) assert getattr(extension_handle.message_type, '_concrete_class', None), ( 'Uninitialized concrete class found for field %r (message type %r)' % (extension_handle.full_name, extension_handle.message_type.full_name)) result = extension_handle.message_type._concrete_class() try: result._SetListener(self._extended_message._listener_for_children) except ReferenceError: pass else: # Singular scalar -- just return the default without inserting into the # dict. return extension_handle.default_value # Atomically check if another thread has preempted us and, if not, swap # in the new object we just created. If someone has preempted us, we # take that object and discard ours. # WARNING: We are relying on setdefault() being atomic. This is true # in CPython but we haven't investigated others. This warning appears # in several other locations in this file. result = self._extended_message._fields.setdefault( extension_handle, result) return result def __eq__(self, other): if not isinstance(other, self.__class__): return False my_fields = self._extended_message.ListFields() other_fields = other._extended_message.ListFields() # Get rid of non-extension fields. my_fields = [field for field in my_fields if field.is_extension] other_fields = [field for field in other_fields if field.is_extension] return my_fields == other_fields def __ne__(self, other): return not self == other def __len__(self): fields = self._extended_message.ListFields() # Get rid of non-extension fields. extension_fields = [field for field in fields if field[0].is_extension] return len(extension_fields) def __hash__(self): raise TypeError('unhashable object') # Note that this is only meaningful for non-repeated, scalar extension # fields. Note also that we may have to call _Modified() when we do # successfully set a field this way, to set any necessary "has" bits in the # ancestors of the extended message. def __setitem__(self, extension_handle, value): """If extension_handle specifies a non-repeated, scalar extension field, sets the value of that field. """ _VerifyExtensionHandle(self._extended_message, extension_handle) if (extension_handle.label == FieldDescriptor.LABEL_REPEATED or extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE): raise TypeError( 'Cannot assign to extension "%s" because it is a repeated or ' 'composite type.' % extension_handle.full_name) # It's slightly wasteful to lookup the type checker each time, # but we expect this to be a vanishingly uncommon case anyway. type_checker = type_checkers.GetTypeChecker(extension_handle) # pylint: disable=protected-access self._extended_message._fields[extension_handle] = ( type_checker.CheckValue(value)) self._extended_message._Modified() def __delitem__(self, extension_handle): self._extended_message.ClearExtension(extension_handle) def _FindExtensionByName(self, name): """Tries to find a known extension with the specified name. Args: name: Extension full name. Returns: Extension field descriptor. """ return self._extended_message._extensions_by_name.get(name, None) def _FindExtensionByNumber(self, number): """Tries to find a known extension with the field number. Args: number: Extension field number. Returns: Extension field descriptor. """ return self._extended_message._extensions_by_number.get(number, None) def __iter__(self): # Return a generator over the populated extension fields return (f[0] for f in self._extended_message.ListFields() if f[0].is_extension) def __contains__(self, extension_handle): _VerifyExtensionHandle(self._extended_message, extension_handle) if extension_handle not in self._extended_message._fields: return False if extension_handle.label == FieldDescriptor.LABEL_REPEATED: return bool(self._extended_message._fields.get(extension_handle)) if extension_handle.cpp_type == FieldDescriptor.CPPTYPE_MESSAGE: value = self._extended_message._fields.get(extension_handle) # pylint: disable=protected-access return value is not None and value._is_present_in_parent return True
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