descriptor_database.py 5.3 KB

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  1. # Protocol Buffers - Google's data interchange format
  2. # Copyright 2008 Google Inc. All rights reserved.
  3. #
  4. # Use of this source code is governed by a BSD-style
  5. # license that can be found in the LICENSE file or at
  6. # https://developers.google.com/open-source/licenses/bsd
  7. """Provides a container for DescriptorProtos."""
  8. __author__ = 'matthewtoia@google.com (Matt Toia)'
  9. import warnings
  10. class Error(Exception):
  11. pass
  12. class DescriptorDatabaseConflictingDefinitionError(Error):
  13. """Raised when a proto is added with the same name & different descriptor."""
  14. class DescriptorDatabase(object):
  15. """A container accepting FileDescriptorProtos and maps DescriptorProtos."""
  16. def __init__(self):
  17. self._file_desc_protos_by_file = {}
  18. self._file_desc_protos_by_symbol = {}
  19. def Add(self, file_desc_proto):
  20. """Adds the FileDescriptorProto and its types to this database.
  21. Args:
  22. file_desc_proto: The FileDescriptorProto to add.
  23. Raises:
  24. DescriptorDatabaseConflictingDefinitionError: if an attempt is made to
  25. add a proto with the same name but different definition than an
  26. existing proto in the database.
  27. """
  28. proto_name = file_desc_proto.name
  29. if proto_name not in self._file_desc_protos_by_file:
  30. self._file_desc_protos_by_file[proto_name] = file_desc_proto
  31. elif self._file_desc_protos_by_file[proto_name] != file_desc_proto:
  32. raise DescriptorDatabaseConflictingDefinitionError(
  33. '%s already added, but with different descriptor.' % proto_name)
  34. else:
  35. return
  36. # Add all the top-level descriptors to the index.
  37. package = file_desc_proto.package
  38. for message in file_desc_proto.message_type:
  39. for name in _ExtractSymbols(message, package):
  40. self._AddSymbol(name, file_desc_proto)
  41. for enum in file_desc_proto.enum_type:
  42. self._AddSymbol(('.'.join((package, enum.name))), file_desc_proto)
  43. for enum_value in enum.value:
  44. self._file_desc_protos_by_symbol[
  45. '.'.join((package, enum_value.name))] = file_desc_proto
  46. for extension in file_desc_proto.extension:
  47. self._AddSymbol(('.'.join((package, extension.name))), file_desc_proto)
  48. for service in file_desc_proto.service:
  49. self._AddSymbol(('.'.join((package, service.name))), file_desc_proto)
  50. def FindFileByName(self, name):
  51. """Finds the file descriptor proto by file name.
  52. Typically the file name is a relative path ending to a .proto file. The
  53. proto with the given name will have to have been added to this database
  54. using the Add method or else an error will be raised.
  55. Args:
  56. name: The file name to find.
  57. Returns:
  58. The file descriptor proto matching the name.
  59. Raises:
  60. KeyError if no file by the given name was added.
  61. """
  62. return self._file_desc_protos_by_file[name]
  63. def FindFileContainingSymbol(self, symbol):
  64. """Finds the file descriptor proto containing the specified symbol.
  65. The symbol should be a fully qualified name including the file descriptor's
  66. package and any containing messages. Some examples:
  67. 'some.package.name.Message'
  68. 'some.package.name.Message.NestedEnum'
  69. 'some.package.name.Message.some_field'
  70. The file descriptor proto containing the specified symbol must be added to
  71. this database using the Add method or else an error will be raised.
  72. Args:
  73. symbol: The fully qualified symbol name.
  74. Returns:
  75. The file descriptor proto containing the symbol.
  76. Raises:
  77. KeyError if no file contains the specified symbol.
  78. """
  79. try:
  80. return self._file_desc_protos_by_symbol[symbol]
  81. except KeyError:
  82. # Fields, enum values, and nested extensions are not in
  83. # _file_desc_protos_by_symbol. Try to find the top level
  84. # descriptor. Non-existent nested symbol under a valid top level
  85. # descriptor can also be found. The behavior is the same with
  86. # protobuf C++.
  87. top_level, _, _ = symbol.rpartition('.')
  88. try:
  89. return self._file_desc_protos_by_symbol[top_level]
  90. except KeyError:
  91. # Raise the original symbol as a KeyError for better diagnostics.
  92. raise KeyError(symbol)
  93. def FindFileContainingExtension(self, extendee_name, extension_number):
  94. # TODO: implement this API.
  95. return None
  96. def FindAllExtensionNumbers(self, extendee_name):
  97. # TODO: implement this API.
  98. return []
  99. def _AddSymbol(self, name, file_desc_proto):
  100. if name in self._file_desc_protos_by_symbol:
  101. warn_msg = ('Conflict register for file "' + file_desc_proto.name +
  102. '": ' + name +
  103. ' is already defined in file "' +
  104. self._file_desc_protos_by_symbol[name].name + '"')
  105. warnings.warn(warn_msg, RuntimeWarning)
  106. self._file_desc_protos_by_symbol[name] = file_desc_proto
  107. def _ExtractSymbols(desc_proto, package):
  108. """Pulls out all the symbols from a descriptor proto.
  109. Args:
  110. desc_proto: The proto to extract symbols from.
  111. package: The package containing the descriptor type.
  112. Yields:
  113. The fully qualified name found in the descriptor.
  114. """
  115. message_name = package + '.' + desc_proto.name if package else desc_proto.name
  116. yield message_name
  117. for nested_type in desc_proto.nested_type:
  118. for symbol in _ExtractSymbols(nested_type, message_name):
  119. yield symbol
  120. for enum_type in desc_proto.enum_type:
  121. yield '.'.join((message_name, enum_type.name))