'''Generate header file for nanopb from a ProtoBuf FileDescriptorSet.''' import google.protobuf.descriptor_pb2 as descriptor import nanopb_pb2 import os.path # Values are tuple (c type, pb ltype) FieldD = descriptor.FieldDescriptorProto datatypes = { FieldD.TYPE_BOOL: ('bool', 'PB_LTYPE_VARINT'), FieldD.TYPE_DOUBLE: ('double', 'PB_LTYPE_FIXED64'), FieldD.TYPE_FIXED32: ('uint32_t', 'PB_LTYPE_FIXED32'), FieldD.TYPE_FIXED64: ('uint64_t', 'PB_LTYPE_FIXED64'), FieldD.TYPE_FLOAT: ('float', 'PB_LTYPE_FIXED32'), FieldD.TYPE_INT32: ('int32_t', 'PB_LTYPE_VARINT'), FieldD.TYPE_INT64: ('int64_t', 'PB_LTYPE_VARINT'), FieldD.TYPE_SFIXED32: ('int32_t', 'PB_LTYPE_FIXED'), FieldD.TYPE_SFIXED64: ('int64_t', 'PB_LTYPE_FIXED'), FieldD.TYPE_SINT32: ('int32_t', 'PB_LTYPE_SVARINT'), FieldD.TYPE_SINT64: ('int64_t', 'PB_LTYPE_SVARINT'), FieldD.TYPE_UINT32: ('uint32_t', 'PB_LTYPE_VARINT'), FieldD.TYPE_UINT64: ('uint64_t', 'PB_LTYPE_VARINT') } class Names: '''Keeps a set of nested names and formats them to C identifier. You can subclass this with your own implementation. ''' def __init__(self, parts = ()): if isinstance(parts, Names): parts = parts.parts self.parts = tuple(parts) def __str__(self): return '_'.join(self.parts) def __add__(self, other): if isinstance(other, (str, unicode)): return Names(self.parts + (other,)) elif isinstance(other, tuple): return Names(self.parts + other) else: raise ValueError("Name parts should be of type str") def names_from_type_name(type_name): '''Parse Names() from FieldDescriptorProto type_name''' if type_name[0] != '.': raise NotImplementedError("Lookup of non-absolute type names is not supported") return Names(type_name[1:].split('.')) class Enum: def __init__(self, names, desc): '''desc is EnumDescriptorProto''' self.names = names + desc.name self.values = [(self.names + x.name, x.number) for x in desc.value] def __str__(self): result = 'typedef enum {\n' result += ',\n'.join([" %s = %d" % x for x in self.values]) result += '\n} %s;' % self.names return result class Field: def __init__(self, struct_name, desc): '''desc is FieldDescriptorProto''' self.tag = desc.number self.struct_name = struct_name self.name = desc.name self.default = None self.max_size = None self.max_count = None self.array_decl = "" # Parse nanopb-specific field options if desc.options.HasExtension(nanopb_pb2.nanopb): ext = desc.options.Extensions[nanopb_pb2.nanopb] if ext.HasField("max_size"): self.max_size = ext.max_size if ext.HasField("max_count"): self.max_count = ext.max_count if desc.HasField('default_value'): self.default = desc.default_value # Decide HTYPE # HTYPE is the high-order nibble of nanopb field description, # defining whether value is required/optional/repeated. is_callback = False if desc.label == FieldD.LABEL_REQUIRED: self.htype = 'PB_HTYPE_REQUIRED' elif desc.label == FieldD.LABEL_OPTIONAL: self.htype = 'PB_HTYPE_OPTIONAL' elif desc.label == FieldD.LABEL_REPEATED: if self.max_count is None: is_callback = True else: self.htype = 'PB_HTYPE_ARRAY' self.array_decl = '[%d]' % self.max_count else: raise NotImplementedError(desc.label) # Decide LTYPE and CTYPE # LTYPE is the low-order nibble of nanopb field description, # defining how to decode an individual value. # CTYPE is the name of the c type to use in the struct. if datatypes.has_key(desc.type): self.ctype, self.ltype = datatypes[desc.type] elif desc.type == FieldD.TYPE_ENUM: self.ltype = 'PB_LTYPE_VARINT' self.ctype = names_from_type_name(desc.type_name) if self.default is not None: self.default = self.ctype + self.default elif desc.type == FieldD.TYPE_STRING: self.ltype = 'PB_LTYPE_STRING' if self.max_size is None: is_callback = True else: self.ctype = 'char' self.array_decl += '[%d]' % self.max_size elif desc.type == FieldD.TYPE_BYTES: self.ltype = 'PB_LTYPE_BYTES' if self.max_size is None: is_callback = True else: self.ctype = self.struct_name + self.name + 't' elif desc.type == FieldD.TYPE_MESSAGE: self.ltype = 'PB_LTYPE_SUBMESSAGE' self.ctype = self.submsgname = names_from_type_name(desc.type_name) else: raise NotImplementedError(desc.type) if is_callback: self.htype = 'PB_HTYPE_CALLBACK' self.ctype = 'pb_callback_t' self.array_decl = '' def __cmp__(self, other): return cmp(self.tag, other.tag) def __str__(self): if self.htype == 'PB_HTYPE_OPTIONAL': result = ' bool has_' + self.name + ';\n' elif self.htype == 'PB_HTYPE_ARRAY': result = ' size_t ' + self.name + '_count;\n' else: result = '' result += ' %s %s%s;' % (self.ctype, self.name, self.array_decl) return result def types(self): '''Return definitions for any special types this field might need.''' if self.ltype == 'PB_LTYPE_BYTES' and self.max_size is not None: result = 'typedef struct {\n' result += ' size_t size;\n' result += ' uint8_t bytes[%d];\n' % self.max_size result += '} %s;\n' % self.ctype else: result = None return result def default_decl(self, declaration_only = False): '''Return definition for this field's default value.''' if self.default is None: return None if self.ltype == 'PB_LTYPE_STRING': ctype = 'char' if self.max_size is None: return None # Not implemented else: array_decl = '[%d]' % (self.max_size + 1) default = str(self.default).encode('string_escape') default = default.replace('"', '\\"') default = '"' + default + '"' elif self.ltype == 'PB_LTYPE_BYTES': data = self.default.decode('string_escape') data = ['0x%02x' % ord(c) for c in data] if self.max_size is None: return None # Not implemented else: ctype = self.ctype default = '{%d, {%s}}' % (len(data), ','.join(data)) array_decl = '' else: ctype, default = self.ctype, self.default array_decl = '' if declaration_only: return 'extern const %s %s_default%s;' % (ctype, self.struct_name + self.name, array_decl) else: return 'const %s %s_default%s = %s;' % (ctype, self.struct_name + self.name, array_decl, default) def pb_field_t(self, prev_field_name): '''Return the pb_field_t initializer to use in the constant array. prev_field_name is the name of the previous field or None. ''' result = ' {%d, ' % self.tag result += self.htype if self.ltype is not None: result += ' | ' + self.ltype result += ',\n' if prev_field_name is None: result += ' offsetof(%s, %s),' % (self.struct_name, self.name) else: result += ' pb_delta_end(%s, %s, %s),' % (self.struct_name, self.name, prev_field_name) if self.htype == 'PB_HTYPE_OPTIONAL': result += '\n pb_delta(%s, has_%s, %s),' % (self.struct_name, self.name, self.name) elif self.htype == 'PB_HTYPE_ARRAY': result += '\n pb_delta(%s, %s_count, %s),' % (self.struct_name, self.name, self.name) else: result += ' 0,' if self.htype == 'PB_HTYPE_ARRAY': result += '\n pb_membersize(%s, %s[0]),' % (self.struct_name, self.name) result += ('\n pb_membersize(%s, %s) / pb_membersize(%s, %s[0]),' % (self.struct_name, self.name, self.struct_name, self.name)) elif self.htype != 'PB_HTYPE_CALLBACK' and self.ltype == 'PB_LTYPE_BYTES': result += '\n pb_membersize(%s, bytes),' % self.ctype result += ' 0,' else: result += '\n pb_membersize(%s, %s),' % (self.struct_name, self.name) result += ' 0,' if self.ltype == 'PB_LTYPE_SUBMESSAGE': result += '\n &%s_fields}' % self.submsgname elif self.default is None or self.htype == 'PB_HTYPE_CALLBACK': result += ' 0}' else: result += '\n &%s_default}' % (self.struct_name + self.name) return result class Message: def __init__(self, names, desc): self.name = names self.fields = [Field(self.name, f) for f in desc.field] self.ordered_fields = self.fields[:] self.ordered_fields.sort() def get_dependencies(self): '''Get list of type names that this structure refers to.''' return [str(field.ctype) for field in self.fields] def __str__(self): result = 'typedef struct {\n' result += '\n'.join([str(f) for f in self.ordered_fields]) result += '\n} %s;' % self.name return result def types(self): result = "" for field in self.fields: types = field.types() if types is not None: result += types + '\n' return result def default_decl(self, declaration_only = False): result = "" for field in self.fields: default = field.default_decl(declaration_only) if default is not None: result += default + '\n' return result def fields_declaration(self): result = 'extern const pb_field_t %s_fields[%d];' % (self.name, len(self.fields) + 1) return result def fields_definition(self): result = 'const pb_field_t %s_fields[%d] = {\n' % (self.name, len(self.fields) + 1) prev = None for field in self.ordered_fields: result += field.pb_field_t(prev) result += ',\n\n' prev = field.name result += ' PB_LAST_FIELD\n};' return result def iterate_messages(desc, names = Names()): '''Recursively find all messages. For each, yield name, DescriptorProto.''' if hasattr(desc, 'message_type'): submsgs = desc.message_type else: submsgs = desc.nested_type for submsg in submsgs: sub_names = names + submsg.name yield sub_names, submsg for x in iterate_messages(submsg, sub_names): yield x def parse_file(fdesc): '''Takes a FileDescriptorProto and returns tuple (enum, messages).''' enums = [] messages = [] if fdesc.package: base_name = Names(fdesc.package.split('.')) else: base_name = Names() for enum in fdesc.enum_type: enums.append(Enum(base_name, enum)) for names, message in iterate_messages(fdesc, base_name): messages.append(Message(names, message)) for enum in message.enum_type: enums.append(Enum(names, enum)) return enums, messages def toposort2(data): '''Topological sort. From http://code.activestate.com/recipes/577413-topological-sort/ This function is under the MIT license. ''' for k, v in data.items(): v.discard(k) # Ignore self dependencies extra_items_in_deps = reduce(set.union, data.values()) - set(data.keys()) data.update(dict([(item, set()) for item in extra_items_in_deps])) while True: ordered = set(item for item,dep in data.items() if not dep) if not ordered: break for item in sorted(ordered): yield item data = dict([(item, (dep - ordered)) for item,dep in data.items() if item not in ordered]) assert not data, "A cyclic dependency exists amongst %r" % data def sort_dependencies(messages): '''Sort a list of Messages based on dependencies.''' dependencies = {} message_by_name = {} for message in messages: dependencies[str(message.name)] = set(message.get_dependencies()) message_by_name[str(message.name)] = message for msgname in toposort2(dependencies): if msgname in message_by_name: yield message_by_name[msgname] def generate_header(headername, enums, messages): '''Generate content for a header file. Generates strings, which should be concatenated and stored to file. ''' yield '/* Automatically generated nanopb header */\n' symbol = headername.replace('.', '_').upper() yield '#ifndef _PB_%s_\n' % symbol yield '#define _PB_%s_\n' % symbol yield '#include \n\n' yield '/* Enum definitions */\n' for enum in enums: yield str(enum) + '\n\n' yield '/* Struct definitions */\n' for msg in sort_dependencies(messages): yield msg.types() yield str(msg) + '\n\n' yield '/* Default values for struct fields */\n' for msg in messages: yield msg.default_decl(True) yield '\n' yield '/* Struct field encoding specification for nanopb */\n' for msg in messages: yield msg.fields_declaration() + '\n' yield '\n#endif\n' def generate_source(headername, enums, messages): '''Generate content for a source file.''' yield '/* Automatically generated nanopb constant definitions */\n' yield '#include "%s"\n\n' % headername for msg in messages: yield msg.default_decl(False) yield '\n\n' for msg in messages: yield msg.fields_definition() + '\n\n' if __name__ == '__main__': import sys import os.path if len(sys.argv) != 2: print "Usage: " + sys.argv[0] + " file.pb" print "where file.pb has been compiled from .proto by:" print "protoc -ofile.pb file.proto" print "Output fill be written to file.pb.h and file.pb.c" sys.exit(1) data = open(sys.argv[1]).read() fdesc = descriptor.FileDescriptorSet.FromString(data) enums, messages = parse_file(fdesc.file[0]) noext = os.path.splitext(sys.argv[1])[0] headername = noext + '.pb.h' sourcename = noext + '.pb.c' headerbasename = os.path.basename(headername) print "Writing to " + headername + " and " + sourcename header = open(headername, 'w') for part in generate_header(headerbasename, enums, messages): header.write(part) source = open(sourcename, 'w') for part in generate_source(headerbasename, enums, messages): source.write(part)