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Diffstat (limited to 'python/google/protobuf/descriptor_pool.py')
| -rw-r--r-- | python/google/protobuf/descriptor_pool.py | 643 |
1 files changed, 643 insertions, 0 deletions
diff --git a/python/google/protobuf/descriptor_pool.py b/python/google/protobuf/descriptor_pool.py new file mode 100644 index 0000000..372f458 --- /dev/null +++ b/python/google/protobuf/descriptor_pool.py @@ -0,0 +1,643 @@ +# Protocol Buffers - Google's data interchange format +# Copyright 2008 Google Inc. All rights reserved. +# http://code.google.com/p/protobuf/ +# +# 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. + +"""Provides DescriptorPool to use as a container for proto2 descriptors. + +The DescriptorPool is used in conjection with a DescriptorDatabase to maintain +a collection of protocol buffer descriptors for use when dynamically creating +message types at runtime. + +For most applications protocol buffers should be used via modules generated by +the protocol buffer compiler tool. This should only be used when the type of +protocol buffers used in an application or library cannot be predetermined. + +Below is a straightforward example on how to use this class: + + pool = DescriptorPool() + file_descriptor_protos = [ ... ] + for file_descriptor_proto in file_descriptor_protos: + pool.Add(file_descriptor_proto) + my_message_descriptor = pool.FindMessageTypeByName('some.package.MessageType') + +The message descriptor can be used in conjunction with the message_factory +module in order to create a protocol buffer class that can be encoded and +decoded. + +If you want to get a Python class for the specified proto, use the +helper functions inside google.protobuf.message_factory +directly instead of this class. +""" + +__author__ = 'matthewtoia@google.com (Matt Toia)' + +import sys + +from google.protobuf import descriptor +from google.protobuf import descriptor_database +from google.protobuf import text_encoding + + +def _NormalizeFullyQualifiedName(name): + """Remove leading period from fully-qualified type name. + + Due to b/13860351 in descriptor_database.py, types in the root namespace are + generated with a leading period. This function removes that prefix. + + Args: + name: A str, the fully-qualified symbol name. + + Returns: + A str, the normalized fully-qualified symbol name. + """ + return name.lstrip('.') + + +class DescriptorPool(object): + """A collection of protobufs dynamically constructed by descriptor protos.""" + + def __init__(self, descriptor_db=None): + """Initializes a Pool of proto buffs. + + The descriptor_db argument to the constructor is provided to allow + specialized file descriptor proto lookup code to be triggered on demand. An + example would be an implementation which will read and compile a file + specified in a call to FindFileByName() and not require the call to Add() + at all. Results from this database will be cached internally here as well. + + Args: + descriptor_db: A secondary source of file descriptors. + """ + + self._internal_db = descriptor_database.DescriptorDatabase() + self._descriptor_db = descriptor_db + self._descriptors = {} + self._enum_descriptors = {} + self._file_descriptors = {} + + def Add(self, file_desc_proto): + """Adds the FileDescriptorProto and its types to this pool. + + Args: + file_desc_proto: The FileDescriptorProto to add. + """ + + self._internal_db.Add(file_desc_proto) + + def AddDescriptor(self, desc): + """Adds a Descriptor to the pool, non-recursively. + + If the Descriptor contains nested messages or enums, the caller must + explicitly register them. This method also registers the FileDescriptor + associated with the message. + + Args: + desc: A Descriptor. + """ + if not isinstance(desc, descriptor.Descriptor): + raise TypeError('Expected instance of descriptor.Descriptor.') + + self._descriptors[desc.full_name] = desc + self.AddFileDescriptor(desc.file) + + def AddEnumDescriptor(self, enum_desc): + """Adds an EnumDescriptor to the pool. + + This method also registers the FileDescriptor associated with the message. + + Args: + enum_desc: An EnumDescriptor. + """ + + if not isinstance(enum_desc, descriptor.EnumDescriptor): + raise TypeError('Expected instance of descriptor.EnumDescriptor.') + + self._enum_descriptors[enum_desc.full_name] = enum_desc + self.AddFileDescriptor(enum_desc.file) + + def AddFileDescriptor(self, file_desc): + """Adds a FileDescriptor to the pool, non-recursively. + + If the FileDescriptor contains messages or enums, the caller must explicitly + register them. + + Args: + file_desc: A FileDescriptor. + """ + + if not isinstance(file_desc, descriptor.FileDescriptor): + raise TypeError('Expected instance of descriptor.FileDescriptor.') + self._file_descriptors[file_desc.name] = file_desc + + def FindFileByName(self, file_name): + """Gets a FileDescriptor by file name. + + Args: + file_name: The path to the file to get a descriptor for. + + Returns: + A FileDescriptor for the named file. + + Raises: + KeyError: if the file can not be found in the pool. + """ + + try: + return self._file_descriptors[file_name] + except KeyError: + pass + + try: + file_proto = self._internal_db.FindFileByName(file_name) + except KeyError: + _, error, _ = sys.exc_info() #PY25 compatible for GAE. + if self._descriptor_db: + file_proto = self._descriptor_db.FindFileByName(file_name) + else: + raise error + if not file_proto: + raise KeyError('Cannot find a file named %s' % file_name) + return self._ConvertFileProtoToFileDescriptor(file_proto) + + def FindFileContainingSymbol(self, symbol): + """Gets the FileDescriptor for the file containing the specified symbol. + + Args: + symbol: The name of the symbol to search for. + + Returns: + A FileDescriptor that contains the specified symbol. + + Raises: + KeyError: if the file can not be found in the pool. + """ + + symbol = _NormalizeFullyQualifiedName(symbol) + try: + return self._descriptors[symbol].file + except KeyError: + pass + + try: + return self._enum_descriptors[symbol].file + except KeyError: + pass + + try: + file_proto = self._internal_db.FindFileContainingSymbol(symbol) + except KeyError: + _, error, _ = sys.exc_info() #PY25 compatible for GAE. + if self._descriptor_db: + file_proto = self._descriptor_db.FindFileContainingSymbol(symbol) + else: + raise error + if not file_proto: + raise KeyError('Cannot find a file containing %s' % symbol) + return self._ConvertFileProtoToFileDescriptor(file_proto) + + def FindMessageTypeByName(self, full_name): + """Loads the named descriptor from the pool. + + Args: + full_name: The full name of the descriptor to load. + + Returns: + The descriptor for the named type. + """ + + full_name = _NormalizeFullyQualifiedName(full_name) + if full_name not in self._descriptors: + self.FindFileContainingSymbol(full_name) + return self._descriptors[full_name] + + def FindEnumTypeByName(self, full_name): + """Loads the named enum descriptor from the pool. + + Args: + full_name: The full name of the enum descriptor to load. + + Returns: + The enum descriptor for the named type. + """ + + full_name = _NormalizeFullyQualifiedName(full_name) + if full_name not in self._enum_descriptors: + self.FindFileContainingSymbol(full_name) + return self._enum_descriptors[full_name] + + def _ConvertFileProtoToFileDescriptor(self, file_proto): + """Creates a FileDescriptor from a proto or returns a cached copy. + + This method also has the side effect of loading all the symbols found in + the file into the appropriate dictionaries in the pool. + + Args: + file_proto: The proto to convert. + + Returns: + A FileDescriptor matching the passed in proto. + """ + + if file_proto.name not in self._file_descriptors: + built_deps = list(self._GetDeps(file_proto.dependency)) + direct_deps = [self.FindFileByName(n) for n in file_proto.dependency] + + file_descriptor = descriptor.FileDescriptor( + name=file_proto.name, + package=file_proto.package, + options=file_proto.options, + serialized_pb=file_proto.SerializeToString(), + dependencies=direct_deps) + scope = {} + + # This loop extracts all the message and enum types from all the + # dependencoes of the file_proto. This is necessary to create the + # scope of available message types when defining the passed in + # file proto. + for dependency in built_deps: + scope.update(self._ExtractSymbols( + dependency.message_types_by_name.values())) + scope.update((_PrefixWithDot(enum.full_name), enum) + for enum in dependency.enum_types_by_name.values()) + + for message_type in file_proto.message_type: + message_desc = self._ConvertMessageDescriptor( + message_type, file_proto.package, file_descriptor, scope) + file_descriptor.message_types_by_name[message_desc.name] = message_desc + + for enum_type in file_proto.enum_type: + file_descriptor.enum_types_by_name[enum_type.name] = ( + self._ConvertEnumDescriptor(enum_type, file_proto.package, + file_descriptor, None, scope)) + + for index, extension_proto in enumerate(file_proto.extension): + extension_desc = self.MakeFieldDescriptor( + extension_proto, file_proto.package, index, is_extension=True) + extension_desc.containing_type = self._GetTypeFromScope( + file_descriptor.package, extension_proto.extendee, scope) + self.SetFieldType(extension_proto, extension_desc, + file_descriptor.package, scope) + file_descriptor.extensions_by_name[extension_desc.name] = extension_desc + + for desc_proto in file_proto.message_type: + self.SetAllFieldTypes(file_proto.package, desc_proto, scope) + + if file_proto.package: + desc_proto_prefix = _PrefixWithDot(file_proto.package) + else: + desc_proto_prefix = '' + + for desc_proto in file_proto.message_type: + desc = self._GetTypeFromScope(desc_proto_prefix, desc_proto.name, scope) + file_descriptor.message_types_by_name[desc_proto.name] = desc + self.Add(file_proto) + self._file_descriptors[file_proto.name] = file_descriptor + + return self._file_descriptors[file_proto.name] + + def _ConvertMessageDescriptor(self, desc_proto, package=None, file_desc=None, + scope=None): + """Adds the proto to the pool in the specified package. + + Args: + desc_proto: The descriptor_pb2.DescriptorProto protobuf message. + package: The package the proto should be located in. + file_desc: The file containing this message. + scope: Dict mapping short and full symbols to message and enum types. + + Returns: + The added descriptor. + """ + + if package: + desc_name = '.'.join((package, desc_proto.name)) + else: + desc_name = desc_proto.name + + if file_desc is None: + file_name = None + else: + file_name = file_desc.name + + if scope is None: + scope = {} + + nested = [ + self._ConvertMessageDescriptor(nested, desc_name, file_desc, scope) + for nested in desc_proto.nested_type] + enums = [ + self._ConvertEnumDescriptor(enum, desc_name, file_desc, None, scope) + for enum in desc_proto.enum_type] + fields = [self.MakeFieldDescriptor(field, desc_name, index) + for index, field in enumerate(desc_proto.field)] + extensions = [ + self.MakeFieldDescriptor(extension, desc_name, index, is_extension=True) + for index, extension in enumerate(desc_proto.extension)] + oneofs = [ + descriptor.OneofDescriptor(desc.name, '.'.join((desc_name, desc.name)), + index, None, []) + for index, desc in enumerate(desc_proto.oneof_decl)] + extension_ranges = [(r.start, r.end) for r in desc_proto.extension_range] + if extension_ranges: + is_extendable = True + else: + is_extendable = False + desc = descriptor.Descriptor( + name=desc_proto.name, + full_name=desc_name, + filename=file_name, + containing_type=None, + fields=fields, + oneofs=oneofs, + nested_types=nested, + enum_types=enums, + extensions=extensions, + options=desc_proto.options, + is_extendable=is_extendable, + extension_ranges=extension_ranges, + file=file_desc, + serialized_start=None, + serialized_end=None) + for nested in desc.nested_types: + nested.containing_type = desc + for enum in desc.enum_types: + enum.containing_type = desc + for field_index, field_desc in enumerate(desc_proto.field): + if field_desc.HasField('oneof_index'): + oneof_index = field_desc.oneof_index + oneofs[oneof_index].fields.append(fields[field_index]) + fields[field_index].containing_oneof = oneofs[oneof_index] + + scope[_PrefixWithDot(desc_name)] = desc + self._descriptors[desc_name] = desc + return desc + + def _ConvertEnumDescriptor(self, enum_proto, package=None, file_desc=None, + containing_type=None, scope=None): + """Make a protobuf EnumDescriptor given an EnumDescriptorProto protobuf. + + Args: + enum_proto: The descriptor_pb2.EnumDescriptorProto protobuf message. + package: Optional package name for the new message EnumDescriptor. + file_desc: The file containing the enum descriptor. + containing_type: The type containing this enum. + scope: Scope containing available types. + + Returns: + The added descriptor + """ + + if package: + enum_name = '.'.join((package, enum_proto.name)) + else: + enum_name = enum_proto.name + + if file_desc is None: + file_name = None + else: + file_name = file_desc.name + + values = [self._MakeEnumValueDescriptor(value, index) + for index, value in enumerate(enum_proto.value)] + desc = descriptor.EnumDescriptor(name=enum_proto.name, + full_name=enum_name, + filename=file_name, + file=file_desc, + values=values, + containing_type=containing_type, + options=enum_proto.options) + scope['.%s' % enum_name] = desc + self._enum_descriptors[enum_name] = desc + return desc + + def MakeFieldDescriptor(self, field_proto, message_name, index, + is_extension=False): + """Creates a field descriptor from a FieldDescriptorProto. + + For message and enum type fields, this method will do a look up + in the pool for the appropriate descriptor for that type. If it + is unavailable, it will fall back to the _source function to + create it. If this type is still unavailable, construction will + fail. + + Args: + field_proto: The proto describing the field. + message_name: The name of the containing message. + index: Index of the field + is_extension: Indication that this field is for an extension. + + Returns: + An initialized FieldDescriptor object + """ + + if message_name: + full_name = '.'.join((message_name, field_proto.name)) + else: + full_name = field_proto.name + + return descriptor.FieldDescriptor( + name=field_proto.name, + full_name=full_name, + index=index, + number=field_proto.number, + type=field_proto.type, + cpp_type=None, + message_type=None, + enum_type=None, + containing_type=None, + label=field_proto.label, + has_default_value=False, + default_value=None, + is_extension=is_extension, + extension_scope=None, + options=field_proto.options) + + def SetAllFieldTypes(self, package, desc_proto, scope): + """Sets all the descriptor's fields's types. + + This method also sets the containing types on any extensions. + + Args: + package: The current package of desc_proto. + desc_proto: The message descriptor to update. + scope: Enclosing scope of available types. + """ + + package = _PrefixWithDot(package) + + main_desc = self._GetTypeFromScope(package, desc_proto.name, scope) + + if package == '.': + nested_package = _PrefixWithDot(desc_proto.name) + else: + nested_package = '.'.join([package, desc_proto.name]) + + for field_proto, field_desc in zip(desc_proto.field, main_desc.fields): + self.SetFieldType(field_proto, field_desc, nested_package, scope) + + for extension_proto, extension_desc in ( + zip(desc_proto.extension, main_desc.extensions)): + extension_desc.containing_type = self._GetTypeFromScope( + nested_package, extension_proto.extendee, scope) + self.SetFieldType(extension_proto, extension_desc, nested_package, scope) + + for nested_type in desc_proto.nested_type: + self.SetAllFieldTypes(nested_package, nested_type, scope) + + def SetFieldType(self, field_proto, field_desc, package, scope): + """Sets the field's type, cpp_type, message_type and enum_type. + + Args: + field_proto: Data about the field in proto format. + field_desc: The descriptor to modiy. + package: The package the field's container is in. + scope: Enclosing scope of available types. + """ + if field_proto.type_name: + desc = self._GetTypeFromScope(package, field_proto.type_name, scope) + else: + desc = None + + if not field_proto.HasField('type'): + if isinstance(desc, descriptor.Descriptor): + field_proto.type = descriptor.FieldDescriptor.TYPE_MESSAGE + else: + field_proto.type = descriptor.FieldDescriptor.TYPE_ENUM + + field_desc.cpp_type = descriptor.FieldDescriptor.ProtoTypeToCppProtoType( + field_proto.type) + + if (field_proto.type == descriptor.FieldDescriptor.TYPE_MESSAGE + or field_proto.type == descriptor.FieldDescriptor.TYPE_GROUP): + field_desc.message_type = desc + + if field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM: + field_desc.enum_type = desc + + if field_proto.label == descriptor.FieldDescriptor.LABEL_REPEATED: + field_desc.has_default_value = False + field_desc.default_value = [] + elif field_proto.HasField('default_value'): + field_desc.has_default_value = True + if (field_proto.type == descriptor.FieldDescriptor.TYPE_DOUBLE or + field_proto.type == descriptor.FieldDescriptor.TYPE_FLOAT): + field_desc.default_value = float(field_proto.default_value) + elif field_proto.type == descriptor.FieldDescriptor.TYPE_STRING: + field_desc.default_value = field_proto.default_value + elif field_proto.type == descriptor.FieldDescriptor.TYPE_BOOL: + field_desc.default_value = field_proto.default_value.lower() == 'true' + elif field_proto.type == descriptor.FieldDescriptor.TYPE_ENUM: + field_desc.default_value = field_desc.enum_type.values_by_name[ + field_proto.default_value].index + elif field_proto.type == descriptor.FieldDescriptor.TYPE_BYTES: + field_desc.default_value = text_encoding.CUnescape( + field_proto.default_value) + else: + field_desc.default_value = int(field_proto.default_value) + else: + field_desc.has_default_value = False + field_desc.default_value = None + + field_desc.type = field_proto.type + + def _MakeEnumValueDescriptor(self, value_proto, index): + """Creates a enum value descriptor object from a enum value proto. + + Args: + value_proto: The proto describing the enum value. + index: The index of the enum value. + + Returns: + An initialized EnumValueDescriptor object. + """ + + return descriptor.EnumValueDescriptor( + name=value_proto.name, + index=index, + number=value_proto.number, + options=value_proto.options, + type=None) + + def _ExtractSymbols(self, descriptors): + """Pulls out all the symbols from descriptor protos. + + Args: + descriptors: The messages to extract descriptors from. + Yields: + A two element tuple of the type name and descriptor object. + """ + + for desc in descriptors: + yield (_PrefixWithDot(desc.full_name), desc) + for symbol in self._ExtractSymbols(desc.nested_types): + yield symbol + for enum in desc.enum_types: + yield (_PrefixWithDot(enum.full_name), enum) + + def _GetDeps(self, dependencies): + """Recursively finds dependencies for file protos. + + Args: + dependencies: The names of the files being depended on. + + Yields: + Each direct and indirect dependency. + """ + + for dependency in dependencies: + dep_desc = self.FindFileByName(dependency) + yield dep_desc + for parent_dep in dep_desc.dependencies: + yield parent_dep + + def _GetTypeFromScope(self, package, type_name, scope): + """Finds a given type name in the current scope. + + Args: + package: The package the proto should be located in. + type_name: The name of the type to be found in the scope. + scope: Dict mapping short and full symbols to message and enum types. + + Returns: + The descriptor for the requested type. + """ + if type_name not in scope: + components = _PrefixWithDot(package).split('.') + while components: + possible_match = '.'.join(components + [type_name]) + if possible_match in scope: + type_name = possible_match + break + else: + components.pop(-1) + return scope[type_name] + + +def _PrefixWithDot(name): + return name if name.startswith('.') else '.%s' % name |