path: root/generator/nanopb_generator.py

#!/usr/bin/env python

from __future__ import unicode_literals

'''Generate header file for nanopb from a ProtoBuf FileDescriptorSet.'''
nanopb_version = "nanopb-0.3.8-dev"

import sys
import re
from functools import reduce

try:
    # Add some dummy imports to keep packaging tools happy.
    import google, distutils.util # bbfreeze seems to need these
    import pkg_resources # pyinstaller / protobuf 2.5 seem to need these
except:
    # Don't care, we will error out later if it is actually important.
    pass

try:
    import google.protobuf.text_format as text_format
    import google.protobuf.descriptor_pb2 as descriptor
except:
    sys.stderr.write('''
         *************************************************************
         *** Could not import the Google protobuf Python libraries ***
         *** Try installing package 'python-protobuf' or similar.  ***
         *************************************************************
    ''' + '\n')
    raise

try:
    import proto.nanopb_pb2 as nanopb_pb2
    import proto.plugin_pb2 as plugin_pb2
except:
    sys.stderr.write('''
         ********************************************************************
         *** Failed to import the protocol definitions for generator.     ***
         *** You have to run 'make' in the nanopb/generator/proto folder. ***
         ********************************************************************
    ''' + '\n')
    raise

# ---------------------------------------------------------------------------
#                     Generation of single fields
# ---------------------------------------------------------------------------

import time
import os.path

# Values are tuple (c type, pb type, encoded size, int_size_allowed)
FieldD = descriptor.FieldDescriptorProto
datatypes = {
    FieldD.TYPE_BOOL:       ('bool',     'BOOL',        1,  False),
    FieldD.TYPE_DOUBLE:     ('double',   'DOUBLE',      8,  False),
    FieldD.TYPE_FIXED32:    ('uint32_t', 'FIXED32',     4,  False),
    FieldD.TYPE_FIXED64:    ('uint64_t', 'FIXED64',     8,  False),
    FieldD.TYPE_FLOAT:      ('float',    'FLOAT',       4,  False),
    FieldD.TYPE_INT32:      ('int32_t',  'INT32',      10,  True),
    FieldD.TYPE_INT64:      ('int64_t',  'INT64',      10,  True),
    FieldD.TYPE_SFIXED32:   ('int32_t',  'SFIXED32',    4,  False),
    FieldD.TYPE_SFIXED64:   ('int64_t',  'SFIXED64',    8,  False),
    FieldD.TYPE_SINT32:     ('int32_t',  'SINT32',      5,  True),
    FieldD.TYPE_SINT64:     ('int64_t',  'SINT64',     10,  True),
    FieldD.TYPE_UINT32:     ('uint32_t', 'UINT32',      5,  True),
    FieldD.TYPE_UINT64:     ('uint64_t', 'UINT64',     10,  True)
}

# Integer size overrides (from .proto settings)
intsizes = {
    nanopb_pb2.IS_8:     'int8_t',
    nanopb_pb2.IS_16:    'int16_t',
    nanopb_pb2.IS_32:    'int32_t',
    nanopb_pb2.IS_64:    'int64_t',
}

# String types (for python 2 / python 3 compatibility)
try:
    strtypes = (unicode, str)
except NameError:
    strtypes = (str, )

class Names:
    '''Keeps a set of nested names and formats them to C identifier.'''
    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, strtypes):
            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 __eq__(self, other):
        return isinstance(other, Names) and self.parts == other.parts

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('.'))

def varint_max_size(max_value):
    '''Returns the maximum number of bytes a varint can take when encoded.'''
    if max_value < 0:
        max_value = 2**64 - max_value
    for i in range(1, 11):
        if (max_value >> (i * 7)) == 0:
            return i
    raise ValueError("Value too large for varint: " + str(max_value))

assert varint_max_size(-1) == 10
assert varint_max_size(0) == 1
assert varint_max_size(127) == 1
assert varint_max_size(128) == 2

class EncodedSize:
    '''Class used to represent the encoded size of a field or a message.
    Consists of a combination of symbolic sizes and integer sizes.'''
    def __init__(self, value = 0, symbols = []):
        if isinstance(value, EncodedSize):
            self.value = value.value
            self.symbols = value.symbols
        elif isinstance(value, strtypes + (Names,)):
            self.symbols = [str(value)]
            self.value = 0
        else:
            self.value = value
            self.symbols = symbols

    def __add__(self, other):
        if isinstance(other, int):
            return EncodedSize(self.value + other, self.symbols)
        elif isinstance(other, strtypes + (Names,)):
            return EncodedSize(self.value, self.symbols + [str(other)])
        elif isinstance(other, EncodedSize):
            return EncodedSize(self.value + other.value, self.symbols + other.symbols)
        else:
            raise ValueError("Cannot add size: " + repr(other))

    def __mul__(self, other):
        if isinstance(other, int):
            return EncodedSize(self.value * other, [str(other) + '*' + s for s in self.symbols])
        else:
            raise ValueError("Cannot multiply size: " + repr(other))

    def __str__(self):
        if not self.symbols:
            return str(self.value)
        else:
            return '(' + str(self.value) + ' + ' + ' + '.join(self.symbols) + ')'

    def upperlimit(self):
        if not self.symbols:
            return self.value
        else:
            return 2**32 - 1

class Enum:
    def __init__(self, names, desc, enum_options):
        '''desc is EnumDescriptorProto'''

        self.options = enum_options
        self.names = names + desc.name

        if enum_options.long_names:
            self.values = [(self.names + x.name, x.number) for x in desc.value]
        else:
            self.values = [(names + x.name, x.number) for x in desc.value]

        self.value_longnames = [self.names + x.name for x in desc.value]
        self.packed = enum_options.packed_enum

    def has_negative(self):
        for n, v in self.values:
            if v < 0:
                return True
        return False

    def encoded_size(self):
        return max([varint_max_size(v) for n,v in self.values])

    def __str__(self):
        result = 'typedef enum _%s {\n' % self.names
        result += ',\n'.join(["    %s = %d" % x for x in self.values])
        result += '\n}'

        if self.packed:
            result += ' pb_packed'

        result += ' %s;' % self.names

        result += '\n#define _%s_MIN %s' % (self.names, self.values[0][0])
        result += '\n#define _%s_MAX %s' % (self.names, self.values[-1][0])
        result += '\n#define _%s_ARRAYSIZE ((%s)(%s+1))' % (self.names, self.names, self.values[-1][0])

        if not self.options.long_names:
            # Define the long names always so that enum value references
            # from other files work properly.
            for i, x in enumerate(self.values):
                result += '\n#define %s %s' % (self.value_longnames[i], x[0])

        return result

class FieldMaxSize:
    def __init__(self, worst = 0, checks = [], field_name = 'undefined'):
        if isinstance(worst, list):
            self.worst = max(i for i in worst if i is not None)
        else:
            self.worst = worst

        self.worst_field = field_name
        self.checks = list(checks)

    def extend(self, extend, field_name = None):
        self.worst = max(self.worst, extend.worst)

        if self.worst == extend.worst:
            self.worst_field = extend.worst_field

        self.checks.extend(extend.checks)

class Field:
    def __init__(self, struct_name, desc, field_options):
        '''desc is FieldDescriptorProto'''
        self.tag = desc.number
        self.struct_name = struct_name
        self.union_name = None
        self.name = desc.name
        self.default = None
        self.max_size = None
        self.max_count = None
        self.array_decl = ""
        self.enc_size = None
        self.ctype = None

        self.inline = None
        if field_options.type == nanopb_pb2.FT_INLINE:
            field_options.type = nanopb_pb2.FT_STATIC
            self.inline = nanopb_pb2.FT_INLINE

        # Parse field options
        if field_options.HasField("max_size"):
            self.max_size = field_options.max_size

        if field_options.HasField("max_count"):
            self.max_count = field_options.max_count

        if desc.HasField('default_value'):
            self.default = desc.default_value

        # Check field rules, i.e. required/optional/repeated.
        can_be_static = True
        if desc.label == FieldD.LABEL_REPEATED:
            self.rules = 'REPEATED'
            if self.max_count is None:
                can_be_static = False
            else:
                self.array_decl = '[%d]' % self.max_count
        elif field_options.HasField("proto3"):
            self.rules = 'SINGULAR'
        elif desc.label == FieldD.LABEL_REQUIRED:
            self.rules = 'REQUIRED'
        elif desc.label == FieldD.LABEL_OPTIONAL:
            self.rules = 'OPTIONAL'
        else:
            raise NotImplementedError(desc.label)

        # Check if the field can be implemented with static allocation
        # i.e. whether the data size is known.
        if desc.type == FieldD.TYPE_STRING and self.max_size is None:
            can_be_static = False

        if desc.type == FieldD.TYPE_BYTES and self.max_size is None:
            can_be_static = False

        # Decide how the field data will be allocated
        if field_options.type == nanopb_pb2.FT_DEFAULT:
            if can_be_static:
                field_options.type = nanopb_pb2.FT_STATIC
            else:
                field_options.type = nanopb_pb2.FT_CALLBACK

        if field_options.type == nanopb_pb2.FT_STATIC and not can_be_static:
            raise Exception("Field %s is defined as static, but max_size or "
                            "max_count is not given." % self.name)

        if field_options.type == nanopb_pb2.FT_STATIC:
            self.allocation = 'STATIC'
        elif field_options.type == nanopb_pb2.FT_POINTER:
            self.allocation = 'POINTER'
        elif field_options.type == nanopb_pb2.FT_CALLBACK:
            self.allocation = 'CALLBACK'
        else:
            raise NotImplementedError(field_options.type)

        # Decide the C data type to use in the struct.
        if desc.type in datatypes:
            self.ctype, self.pbtype, self.enc_size, isa = datatypes[desc.type]

            # Override the field size if user wants to use smaller integers
            if isa and field_options.int_size != nanopb_pb2.IS_DEFAULT:
                self.ctype = intsizes[field_options.int_size]
                if desc.type == FieldD.TYPE_UINT32 or desc.type == FieldD.TYPE_UINT64:
                    self.ctype = 'u' + self.ctype;
        elif desc.type == FieldD.TYPE_ENUM:
            self.pbtype = 'ENUM'
            self.ctype = names_from_type_name(desc.type_name)
            if self.default is not None:
                self.default = self.ctype + self.default
            self.enc_size = None # Needs to be filled in when enum values are known
        elif desc.type == FieldD.TYPE_STRING:
            self.pbtype = 'STRING'
            self.ctype = 'char'
            if self.allocation == 'STATIC':
                self.ctype = 'char'
                self.array_decl += '[%d]' % self.max_size
                self.enc_size = varint_max_size(self.max_size) + self.max_size
        elif desc.type == FieldD.TYPE_BYTES:
            self.pbtype = 'BYTES'
            if self.allocation == 'STATIC':
                # Inline STATIC for BYTES is like STATIC for STRING.
                if self.inline:
                    self.ctype = 'pb_byte_t'
                    self.array_decl += '[%d]' % self.max_size
                else:
                    self.ctype = self.struct_name + self.name + 't'
                self.enc_size = varint_max_size(self.max_size) + self.max_size
            elif self.allocation == 'POINTER':
                self.ctype = 'pb_bytes_array_t'
        elif desc.type == FieldD.TYPE_MESSAGE:
            self.pbtype = 'MESSAGE'
            self.ctype = self.submsgname = names_from_type_name(desc.type_name)
            self.enc_size = None # Needs to be filled in after the message type is available
        else:
            raise NotImplementedError(desc.type)

    def __lt__(self, other):
        return self.tag < other.tag

    def __str__(self):
        result = ''
        if self.allocation == 'POINTER':
            if self.rules == 'REPEATED':
                result += '    pb_size_t ' + self.name + '_count;\n'

            if self.pbtype == 'MESSAGE':
                # Use struct definition, so recursive submessages are possible
                result += '    struct _%s *%s;' % (self.ctype, self.name)
            elif self.rules == 'REPEATED' and self.pbtype in ['STRING', 'BYTES']:
                # String/bytes arrays need to be defined as pointers to pointers
                result += '    %s **%s;' % (self.ctype, self.name)
            else:
                result += '    %s *%s;' % (self.ctype, self.name)
        elif self.allocation == 'CALLBACK':
            result += '    pb_callback_t %s;' % self.name
        else:
            if self.rules == 'OPTIONAL' and self.allocation == 'STATIC':
                result += '    bool has_' + self.name + ';\n'
            elif self.rules == 'REPEATED' and self.allocation == 'STATIC':
                result += '    pb_size_t ' + self.name + '_count;\n'
            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.pbtype == 'BYTES' and self.allocation == 'STATIC' and not self.inline:
            result = 'typedef PB_BYTES_ARRAY_T(%d) %s;\n' % (self.max_size, self.ctype)
        else:
            result = ''
        return result

    def get_dependencies(self):
        '''Get list of type names used by this field.'''
        if self.allocation == 'STATIC':
            return [str(self.ctype)]
        else:
            return []

    def get_initializer(self, null_init, inner_init_only = False):
        '''Return literal expression for this field's default value.
        null_init: If True, initialize to a 0 value instead of default from .proto
        inner_init_only: If True, exclude initialization for any count/has fields
        '''

        inner_init = None
        if self.pbtype == 'MESSAGE':
            if null_init:
                inner_init = '%s_init_zero' % self.ctype
            else:
                inner_init = '%s_init_default' % self.ctype
        elif self.default is None or null_init:
            if self.pbtype == 'STRING':
                inner_init = '""'
            elif self.pbtype == 'BYTES':
                if self.inline:
                    inner_init = '{0}'
                else:
                    inner_init = '{0, {0}}'
            elif self.pbtype in ('ENUM', 'UENUM'):
                inner_init = '(%s)0' % self.ctype
            else:
                inner_init = '0'
        else:
            if self.pbtype == 'STRING':
                inner_init = self.default.replace('"', '\\"')
                inner_init = '"' + inner_init + '"'
            elif self.pbtype == 'BYTES':
                data = ['0x%02x' % ord(c) for c in self.default]
                if len(data) == 0:
                    if self.inline:
                        inner_init = '{0}'
                    else:
                        inner_init = '{0, {0}}'
                else:
                    if self.inline:
                        inner_init = '{%s}' % ','.join(data)
                    else:
                        inner_init = '{%d, {%s}}' % (len(data), ','.join(data))
            elif self.pbtype in ['FIXED32', 'UINT32']:
                inner_init = str(self.default) + 'u'
            elif self.pbtype in ['FIXED64', 'UINT64']:
                inner_init = str(self.default) + 'ull'
            elif self.pbtype in ['SFIXED64', 'INT64']:
                inner_init = str(self.default) + 'll'
            else:
                inner_init = str(self.default)

        if inner_init_only:
            return inner_init

        outer_init = None
        if self.allocation == 'STATIC':
            if self.rules == 'REPEATED':
                outer_init = '0, {'
                outer_init += ', '.join([inner_init] * self.max_count)
                outer_init += '}'
            elif self.rules == 'OPTIONAL':
                outer_init = 'false, ' + inner_init
            else:
                outer_init = inner_init
        elif self.allocation == 'POINTER':
            if self.rules == 'REPEATED':
                outer_init = '0, NULL'
            else:
                outer_init = 'NULL'
        elif self.allocation == 'CALLBACK':
            if self.pbtype == 'EXTENSION':
                outer_init = 'NULL'
            else:
                outer_init = '{{NULL}, NULL}'

        return outer_init

    def default_decl(self, declaration_only = False):
        '''Return definition for this field's default value.'''
        if self.default is None:
            return None

        ctype = self.ctype
        default = self.get_initializer(False, True)
        array_decl = ''

        if self.pbtype == 'STRING':
            if self.allocation != 'STATIC':
                return None # Not implemented
            array_decl = '[%d]' % self.max_size
        elif self.pbtype == 'BYTES':
            if self.allocation != 'STATIC':
                return None # Not implemented
            if self.inline:
                array_decl = '[%d]' % self.max_size

        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 tags(self):
        '''Return the #define for the tag number of this field.'''
        identifier = '%s_%s_tag' % (self.struct_name, self.name)
        return '#define %-40s %d\n' % (identifier, self.tag)

    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.
        '''

        if self.rules == 'ONEOF':
            if self.anonymous:
                result = '    PB_ANONYMOUS_ONEOF_FIELD(%s, ' % self.union_name
            else:
                result = '    PB_ONEOF_FIELD(%s, ' % self.union_name
        else:
            result = '    PB_FIELD('

        result += '%3d, ' % self.tag
        result += '%-8s, ' % self.pbtype
        result += '%s, ' % self.rules
        result += '%-8s, ' % (self.allocation if not self.inline else "INLINE")
        result += '%s, ' % ("FIRST" if not prev_field_name else "OTHER")
        result += '%s, ' % self.struct_name
        result += '%s, ' % self.name
        result += '%s, ' % (prev_field_name or self.name)

        if self.pbtype == 'MESSAGE':
            result += '&%s_fields)' % self.submsgname
        elif self.default is None:
            result += '0)'
        elif self.pbtype in ['BYTES', 'STRING'] and self.allocation != 'STATIC':
            result += '0)' # Arbitrary size default values not implemented
        elif self.rules == 'OPTEXT':
            result += '0)' # Default value for extensions is not implemented
        else:
            result += '&%s_default)' % (self.struct_name + self.name)

        return result

    def get_last_field_name(self):
        return self.name

    def largest_field_value(self):
        '''Determine if this field needs 16bit or 32bit pb_field_t structure to compile properly.
        Returns numeric value or a C-expression for assert.'''
        check = []
        if self.pbtype == 'MESSAGE' and self.allocation == 'STATIC':
            if self.rules == 'REPEATED':
                check.append('pb_membersize(%s, %s[0])' % (self.struct_name, self.name))
            elif self.rules == 'ONEOF':
                if self.anonymous:
                    check.append('pb_membersize(%s, %s)' % (self.struct_name, self.name))
                else:
                    check.append('pb_membersize(%s, %s.%s)' % (self.struct_name, self.union_name, self.name))
            else:
                check.append('pb_membersize(%s, %s)' % (self.struct_name, self.name))
        elif self.pbtype == 'BYTES' and self.allocation == 'STATIC':
            if self.max_size > 251:
                check.append('pb_membersize(%s, %s)' % (self.struct_name, self.name))

        return FieldMaxSize([self.tag, self.max_size, self.max_count],
                            check,
                            ('%s.%s' % (self.struct_name, self.name)))

    def encoded_size(self, dependencies):
        '''Return the maximum size that this field can take when encoded,
        including the field tag. If the size cannot be determined, returns
        None.'''

        if self.allocation != 'STATIC':
            return None

        if self.pbtype == 'MESSAGE':
            encsize = None
            if str(self.submsgname) in dependencies:
                submsg = dependencies[str(self.submsgname)]
                encsize = submsg.encoded_size(dependencies)
                if encsize is not None:
                    # Include submessage length prefix
                    encsize += varint_max_size(encsize.upperlimit())

            if encsize is None:
                # Submessage or its size cannot be found.
                # This can occur if submessage is defined in different
                # file, and it or its .options could not be found.
                # Instead of direct numeric value, reference the size that
                # has been #defined in the other file.
                encsize = EncodedSize(self.submsgname + 'size')

                # We will have to make a conservative assumption on the length
                # prefix size, though.
                encsize += 5

        elif self.pbtype in ['ENUM', 'UENUM']:
            if str(self.ctype) in dependencies:
                enumtype = dependencies[str(self.ctype)]
                encsize = enumtype.encoded_size()
            else:
                # Conservative assumption
                encsize = 10

        elif self.enc_size is None:
            raise RuntimeError("Could not determine encoded size for %s.%s"
                               % (self.struct_name, self.name))
        else:
            encsize = EncodedSize(self.enc_size)

        encsize += varint_max_size(self.tag << 3) # Tag + wire type

        if self.rules == 'REPEATED':
            # Decoders must be always able to handle unpacked arrays.
            # Therefore we have to reserve space for it, even though
            # we emit packed arrays ourselves.
            encsize *= self.max_count

        return encsize


class ExtensionRange(Field):
    def __init__(self, struct_name, range_start, field_options):
        '''Implements a special pb_extension_t* field in an extensible message
        structure. The range_start signifies the index at which the extensions
        start. Not necessarily all tags above this are extensions, it is merely
        a speed optimization.
        '''
        self.tag = range_start
        self.struct_name = struct_name
        self.name = 'extensions'
        self.pbtype = 'EXTENSION'
        self.rules = 'OPTIONAL'
        self.allocation = 'CALLBACK'
        self.ctype = 'pb_extension_t'
        self.array_decl = ''
        self.default = None
        self.max_size = 0
        self.max_count = 0
        self.inline = None

    def __str__(self):
        return '    pb_extension_t *extensions;'

    def types(self):
        return ''

    def tags(self):
        return ''

    def encoded_size(self, dependencies):
        # We exclude extensions from the count, because they cannot be known
        # until runtime. Other option would be to return None here, but this
        # way the value remains useful if extensions are not used.
        return EncodedSize(0)

class ExtensionField(Field):
    def __init__(self, struct_name, desc, field_options):
        self.fullname = struct_name + desc.name
        self.extendee_name = names_from_type_name(desc.extendee)
        Field.__init__(self, self.fullname + 'struct', desc, field_options)

        if self.rules != 'OPTIONAL':
            self.skip = True
        else:
            self.skip = False
            self.rules = 'OPTEXT'

    def tags(self):
        '''Return the #define for the tag number of this field.'''
        identifier = '%s_tag' % self.fullname
        return '#define %-40s %d\n' % (identifier, self.tag)

    def extension_decl(self):
        '''Declaration of the extension type in the .pb.h file'''
        if self.skip:
            msg = '/* Extension field %s was skipped because only "optional"\n' % self.fullname
            msg +='   type of extension fields is currently supported. */\n'
            return msg

        return ('extern const pb_extension_type_t %s; /* field type: %s */\n' %
            (self.fullname, str(self).strip()))

    def extension_def(self):
        '''Definition of the extension type in the .pb.c file'''

        if self.skip:
            return ''

        result  = 'typedef struct {\n'
        result += str(self)
        result += '\n} %s;\n\n' % self.struct_name
        result += ('static const pb_field_t %s_field = \n  %s;\n\n' %
                    (self.fullname, self.pb_field_t(None)))
        result += 'const pb_extension_type_t %s = {\n' % self.fullname
        result += '    NULL,\n'
        result += '    NULL,\n'
        result += '    &%s_field\n' % self.fullname
        result += '};\n'
        return result


# ---------------------------------------------------------------------------
#                   Generation of oneofs (unions)
# ---------------------------------------------------------------------------

class OneOf(Field):
    def __init__(self, struct_name, oneof_desc):
        self.struct_name = struct_name
        self.name = oneof_desc.name
        self.ctype = 'union'
        self.pbtype = 'oneof'
        self.fields = []
        self.allocation = 'ONEOF'
        self.default = None
        self.rules = 'ONEOF'
        self.anonymous = False
        self.inline = None

    def add_field(self, field):
        if field.allocation == 'CALLBACK':
            raise Exception("Callback fields inside of oneof are not supported"
                            + " (field %s)" % field.name)

        field.union_name = self.name
        field.rules = 'ONEOF'
        field.anonymous = self.anonymous
        self.fields.append(field)
        self.fields.sort(key = lambda f: f.tag)

        # Sort by the lowest tag number inside union
        self.tag = min([f.tag for f in self.fields])

    def __str__(self):
        result = ''
        if self.fields:
            result += '    pb_size_t which_' + self.name + ";\n"
            result += '    union {\n'
            for f in self.fields:
                result += '    ' + str(f).replace('\n', '\n    ') + '\n'
            if self.anonymous:
                result += '    };'
            else:
                result += '    } ' + self.name + ';'
        return result

    def types(self):
        return ''.join([f.types() for f in self.fields])

    def get_dependencies(self):
        deps = []
        for f in self.fields:
            deps += f.get_dependencies()
        return deps

    def get_initializer(self, null_init):
        return '0, {' + self.fields[0].get_initializer(null_init) + '}'

    def default_decl(self, declaration_only = False):
        return None

    def tags(self):
        return ''.join([f.tags() for f in self.fields])

    def pb_field_t(self, prev_field_name):
        result = ',\n'.join([f.pb_field_t(prev_field_name) for f in self.fields])
        return result

    def get_last_field_name(self):
        if self.anonymous:
            return self.fields[-1].name
        else:
            return self.name + '.' + self.fields[-1].name

    def largest_field_value(self):
        largest = FieldMaxSize()
        for f in self.fields:
            largest.extend(f.largest_field_value())
        return largest

    def encoded_size(self, dependencies):
        '''Returns the size of the largest oneof field.'''
        largest = EncodedSize(0)
        for f in self.fields:
            size = EncodedSize(f.encoded_size(dependencies))
            if size.value is None:
                return None
            elif size.symbols:
                return None # Cannot resolve maximum of symbols
            elif size.value > largest.value:
                largest = size

        return largest

# ---------------------------------------------------------------------------
#                   Generation of messages (structures)
# ---------------------------------------------------------------------------


class Message:
    def __init__(self, names, desc, message_options):
        self.name = names
        self.fields = []
        self.oneofs = {}
        no_unions = []

        if message_options.msgid:
            self.msgid = message_options.msgid

        if hasattr(desc, 'oneof_decl'):
            for i, f in enumerate(desc.oneof_decl):
                oneof_options = get_nanopb_suboptions(desc, message_options, self.name + f.name)
                if oneof_options.no_unions:
                    no_unions.append(i) # No union, but add fields normally
                elif oneof_options.type == nanopb_pb2.FT_IGNORE:
                    pass # No union and skip fields also
                else:
                    oneof = OneOf(self.name, f)
                    if oneof_options.anonymous_oneof:
                        oneof.anonymous = True
                    self.oneofs[i] = oneof
                    self.fields.append(oneof)

        for f in desc.field:
            field_options = get_nanopb_suboptions(f, message_options, self.name + f.name)
            if field_options.type == nanopb_pb2.FT_IGNORE:
                continue

            field = Field(self.name, f, field_options)
            if (hasattr(f, 'oneof_index') and
                f.HasField('oneof_index') and
                f.oneof_index not in no_unions):
                if f.oneof_index in self.oneofs:
                    self.oneofs[f.oneof_index].add_field(field)
            else:
                self.fields.append(field)

        if len(desc.extension_range) > 0:
            field_options = get_nanopb_suboptions(desc, message_options, self.name + 'extensions')
            range_start = min([r.start for r in desc.extension_range])
            if field_options.type != nanopb_pb2.FT_IGNORE:
                self.fields.append(ExtensionRange(self.name, range_start, field_options))

        self.packed = message_options.packed_struct
        self.ordered_fields = self.fields[:]
        self.ordered_fields.sort()

    def get_dependencies(self):
        '''Get list of type names that this structure refers to.'''
        deps = []
        for f in self.fields:
            deps += f.get_dependencies()
        return deps

    def __str__(self):
        result = 'typedef struct _%s {\n' % self.name

        if not self.ordered_fields:
            # Empty structs are not allowed in C standard.
            # Therefore add a dummy field if an empty message occurs.
            result += '    char dummy_field;'

        result += '\n'.join([str(f) for f in self.ordered_fields])
        result += '\n/* @@protoc_insertion_point(struct:%s) */' % self.name
        result += '\n}'

        if self.packed:
            result += ' pb_packed'

        result += ' %s;' % self.name

        if self.packed:
            result = 'PB_PACKED_STRUCT_START\n' + result
            result += '\nPB_PACKED_STRUCT_END'

        return result

    def types(self):
        return ''.join([f.types() for f in self.fields])

    def get_initializer(self, null_init):
        if not self.ordered_fields:
            return '{0}'

        parts = []
        for field in self.ordered_fields:
            parts.append(field.get_initializer(null_init))
        return '{' + ', '.join(parts) + '}'

    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 count_required_fields(self):
        '''Returns number of required fields inside this message'''
        count = 0
        for f in self.fields:
            if not isinstance(f, OneOf):
                if f.rules == 'REQUIRED':
                    count += 1
        return count

    def count_all_fields(self):
        count = 0
        for f in self.fields:
            if isinstance(f, OneOf):
                count += len(f.fields)
            else:
                count += 1
        return count

    def fields_declaration(self):
        result = 'extern const pb_field_t %s_fields[%d];' % (self.name, self.count_all_fields() + 1)
        return result

    def fields_definition(self):
        result = 'const pb_field_t %s_fields[%d] = {\n' % (self.name, self.count_all_fields() + 1)

        prev = None
        for field in self.ordered_fields:
            result += field.pb_field_t(prev)
            result += ',\n'
            prev = field.get_last_field_name()

        result += '    PB_LAST_FIELD\n};'
        return result

    def encoded_size(self, dependencies):
        '''Return the maximum size that this message can take when encoded.
        If the size cannot be determined, returns None.
        '''
        size = EncodedSize(0)
        for field in self.fields:
            fsize = field.encoded_size(dependencies)
            if fsize is None:
                return None
            size += fsize

        return size


# ---------------------------------------------------------------------------
#                    Processing of entire .proto files
# ---------------------------------------------------------------------------

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 iterate_extensions(desc, names = Names()):
    '''Recursively find all extensions.
    For each, yield name, FieldDescriptorProto.
    '''
    for extension in desc.extension:
        yield names, extension

    for subname, subdesc in iterate_messages(desc, names):
        for extension in subdesc.extension:
            yield subname, extension

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 list(data.items()):
        v.discard(k) # Ignore self dependencies
    extra_items_in_deps = reduce(set.union, list(data.values()), set()) - set(data.keys())
    data.update(dict([(item, set()) for item in extra_items_in_deps]))
    while True:
        ordered = set(item for item,dep in list(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 list(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 make_identifier(headername):
    '''Make #ifndef identifier that contains uppercase A-Z and digits 0-9'''
    result = ""
    for c in headername.upper():
        if c.isalnum():
            result += c
        else:
            result += '_'
    return result

class ProtoFile:
    def __init__(self, fdesc, file_options):
        '''Takes a FileDescriptorProto and parses it.'''
        self.fdesc = fdesc
        self.file_options = file_options
        self.dependencies = {}
        self.parse()

        # Some of types used in this file probably come from the file itself.
        # Thus it has implicit dependency on itself.
        self.add_dependency(self)

    def parse(self):
        self.enums = []
        self.messages = []
        self.extensions = []

        if self.fdesc.package:
            base_name = Names(self.fdesc.package.split('.'))
        else:
            base_name = Names()

        for enum in self.fdesc.enum_type:
            enum_options = get_nanopb_suboptions(enum, self.file_options, base_name + enum.name)
            self.enums.append(Enum(base_name, enum, enum_options))

        for names, message in iterate_messages(self.fdesc, base_name):
            message_options = get_nanopb_suboptions(message, self.file_options, names)

            if message_options.skip_message:
                continue

            self.messages.append(Message(names, message, message_options))
            for enum in message.enum_type:
                enum_options = get_nanopb_suboptions(enum, message_options, names + enum.name)
                self.enums.append(Enum(names, enum, enum_options))

        for names, extension in iterate_extensions(self.fdesc, base_name):
            field_options = get_nanopb_suboptions(extension, self.file_options, names + extension.name)
            if field_options.type != nanopb_pb2.FT_IGNORE:
                self.extensions.append(ExtensionField(names, extension, field_options))

    def add_dependency(self, other):
        for enum in other.enums:
            self.dependencies[str(enum.names)] = enum

        for msg in other.messages:
            self.dependencies[str(msg.name)] = msg

        # Fix field default values where enum short names are used.
        for enum in other.enums:
            if not enum.options.long_names:
                for message in self.messages:
                    for field in message.fields:
                        if field.default in enum.value_longnames:
                            idx = enum.value_longnames.index(field.default)
                            field.default = enum.values[idx][0]

        # Fix field data types where enums have negative values.
        for enum in other.enums:
            if not enum.has_negative():
                for message in self.messages:
                    for field in message.fields:
                        if field.pbtype == 'ENUM' and field.ctype == enum.names:
                            field.pbtype = 'UENUM'

    def generate_header(self, includes, headername, options):
        '''Generate content for a header file.
        Generates strings, which should be concatenated and stored to file.
        '''

        yield '/* Automatically generated nanopb header */\n'
        if options.notimestamp:
            yield '/* Generated by %s */\n\n' % (nanopb_version)
        else:
            yield '/* Generated by %s at %s. */\n\n' % (nanopb_version, time.asctime())

        if self.fdesc.package:
            symbol = make_identifier(self.fdesc.package + '_' + headername)
        else:
            symbol = make_identifier(headername)
        yield '#ifndef PB_%s_INCLUDED\n' % symbol
        yield '#define PB_%s_INCLUDED\n' % symbol
        try:
            yield options.libformat % ('pb.h')
        except TypeError:
            # no %s specified - use whatever was passed in as options.libformat
            yield options.libformat
        yield '\n'

        for incfile in includes:
            noext = os.path.splitext(incfile)[0]
            yield options.genformat % (noext + options.extension + '.h')
            yield '\n'

        yield '/* @@protoc_insertion_point(includes) */\n'

        yield '#if PB_PROTO_HEADER_VERSION != 30\n'
        yield '#error Regenerate this file with the current version of nanopb generator.\n'
        yield '#endif\n'
        yield '\n'

        yield '#ifdef __cplusplus\n'
        yield 'extern "C" {\n'
        yield '#endif\n\n'

        if self.enums:
            yield '/* Enum definitions */\n'
            for enum in self.enums:
                yield str(enum) + '\n\n'

        if self.messages:
            yield '/* Struct definitions */\n'
            for msg in sort_dependencies(self.messages):
                yield msg.types()
                yield str(msg) + '\n\n'

        if self.extensions:
            yield '/* Extensions */\n'
            for extension in self.extensions:
                yield extension.extension_decl()
            yield '\n'

        if self.messages:
            yield '/* Default values for struct fields */\n'
            for msg in self.messages:
                yield msg.default_decl(True)
            yield '\n'

            yield '/* Initializer values for message structs */\n'
            for msg in self.messages:
                identifier = '%s_init_default' % msg.name
                yield '#define %-40s %s\n' % (identifier, msg.get_initializer(False))
            for msg in self.messages:
                identifier = '%s_init_zero' % msg.name
                yield '#define %-40s %s\n' % (identifier, msg.get_initializer(True))
            yield '\n'

            yield '/* Field tags (for use in manual encoding/decoding) */\n'
            for msg in sort_dependencies(self.messages):
                for field in msg.fields:
                    yield field.tags()
            for extension in self.extensions:
                yield extension.tags()
            yield '\n'

            yield '/* Struct field encoding specification for nanopb */\n'
            for msg in self.messages:
                yield msg.fields_declaration() + '\n'
            yield '\n'

            yield '/* Maximum encoded size of messages (where known) */\n'
            for msg in self.messages:
                msize = msg.encoded_size(self.dependencies)
                identifier = '%s_size' % msg.name
                if msize is not None:
                    yield '#define %-40s %s\n' % (identifier, msize)
                else:
                    yield '/* %s depends on runtime parameters */\n' % identifier
            yield '\n'

            yield '/* Message IDs (where set with "msgid" option) */\n'

            yield '#ifdef PB_MSGID\n'
            for msg in self.messages:
                if hasattr(msg,'msgid'):
                    yield '#define PB_MSG_%d %s\n' % (msg.msgid, msg.name)
            yield '\n'

            symbol = make_identifier(headername.split('.')[0])
            yield '#define %s_MESSAGES \\\n' % symbol

            for msg in self.messages:
                m = "-1"
                msize = msg.encoded_size(self.dependencies)
                if msize is not None:
                    m = msize
                if hasattr(msg,'msgid'):
                    yield '\tPB_MSG(%d,%s,%s) \\\n' % (msg.msgid, m, msg.name)
            yield '\n'

            for msg in self.messages:
                if hasattr(msg,'msgid'):
                    yield '#define %s_msgid %d\n' % (msg.name, msg.msgid)
            yield '\n'

            yield '#endif\n\n'

        yield '#ifdef __cplusplus\n'
        yield '} /* extern "C" */\n'
        yield '#endif\n'

        # End of header
        yield '/* @@protoc_insertion_point(eof) */\n'
        yield '\n#endif\n'

    def generate_source(self, headername, options):
        '''Generate content for a source file.'''

        yield '/* Automatically generated nanopb constant definitions */\n'
        if options.notimestamp:
            yield '/* Generated by %s */\n\n' % (nanopb_version)
        else:
            yield '/* Generated by %s at %s. */\n\n' % (nanopb_version, time.asctime())
        yield options.genformat % (headername)
        yield '\n'
        yield '/* @@protoc_insertion_point(includes) */\n'

        yield '#if PB_PROTO_HEADER_VERSION != 30\n'
        yield '#error Regenerate this file with the current version of nanopb generator.\n'
        yield '#endif\n'
        yield '\n'

        for msg in self.messages:
            yield msg.default_decl(False)

        yield '\n\n'

        for msg in self.messages:
            yield msg.fields_definition() + '\n\n'

        for ext in self.extensions:
            yield ext.extension_def() + '\n'

        # Add checks for numeric limits
        if self.messages:
            largest_msg = max(self.messages, key = lambda m: m.count_required_fields())
            largest_count = largest_msg.count_required_fields()
            if largest_count > 64:
                yield '\n/* Check that missing required fields will be properly detected */\n'
                yield '#if PB_MAX_REQUIRED_FIELDS < %d\n' % largest_count
                yield '#error Properly detecting missing required fields in %s requires \\\n' % largest_msg.name
                yield '       setting PB_MAX_REQUIRED_FIELDS to %d or more.\n' % largest_count
                yield '#endif\n'

        max_field = FieldMaxSize()
        checks_msgnames = []
        for msg in self.messages:
            checks_msgnames.append(msg.name)
            for field in msg.fields:
                max_field.extend(field.largest_field_value())

        worst = max_field.worst
        worst_field = max_field.worst_field
        checks = max_field.checks

        if worst > 255 or checks:
            yield '\n/* Check that field information fits in pb_field_t */\n'

            if worst > 65535 or checks:
                yield '#if !defined(PB_FIELD_32BIT)\n'
                if worst > 65535:
                    yield '#error Field descriptor for %s is too large. Define PB_FIELD_32BIT to fix this.\n' % worst_field
                else:
                    assertion = ' && '.join(str(c) + ' < 65536' for c in checks)
                    msgs = '_'.join(str(n) for n in checks_msgnames)
                    yield '/* If you get an error here, it means that you need to define PB_FIELD_32BIT\n'
                    yield ' * compile-time option. You can do that in pb.h or on compiler command line.\n'
                    yield ' * \n'
                    yield ' * The reason you need to do this is that some of your messages contain tag\n'
                    yield ' * numbers or field sizes that are larger than what can fit in 8 or 16 bit\n'
                    yield ' * field descriptors.\n'
                    yield ' */\n'
                    yield 'PB_STATIC_ASSERT((%s), YOU_MUST_DEFINE_PB_FIELD_32BIT_FOR_MESSAGES_%s)\n'%(assertion,msgs)
                yield '#endif\n\n'

            if worst < 65536:
                yield '#if !defined(PB_FIELD_16BIT) && !defined(PB_FIELD_32BIT)\n'
                if worst > 255:
                    yield '#error Field descriptor for %s is too large. Define PB_FIELD_16BIT to fix this.\n' % worst_field
                else:
                    assertion = ' && '.join(str(c) + ' < 256' for c in checks)
                    msgs = '_'.join(str(n) for n in checks_msgnames)
                    yield '/* If you get an error here, it means that you need to define PB_FIELD_16BIT\n'
                    yield ' * compile-time option. You can do that in pb.h or on compiler command line.\n'
                    yield ' * \n'
                    yield ' * The reason you need to do this is that some of your messages contain tag\n'
                    yield ' * numbers or field sizes that are larger than what can fit in the default\n'
                    yield ' * 8 bit descriptors.\n'
                    yield ' */\n'
                    yield 'PB_STATIC_ASSERT((%s), YOU_MUST_DEFINE_PB_FIELD_16BIT_FOR_MESSAGES_%s)\n'%(assertion,msgs)
                yield '#endif\n\n'

        # Add check for sizeof(double)
        has_double = False
        for msg in self.messages:
            for field in msg.fields:
                if field.ctype == 'double':
                    has_double = True

        if has_double:
            yield '\n'
            yield '/* On some platforms (such as AVR), double is really float.\n'
            yield ' * These are not directly supported by nanopb, but see example_avr_double.\n'
            yield ' * To get rid of this error, remove any double fields from your .proto.\n'
            yield ' */\n'
            yield 'PB_STATIC_ASSERT(sizeof(double) == 8, DOUBLE_MUST_BE_8_BYTES)\n'

        yield '\n'
        yield '/* @@protoc_insertion_point(eof) */\n'

# ---------------------------------------------------------------------------
#                    Options parsing for the .proto files
# ---------------------------------------------------------------------------

from fnmatch import fnmatch

def read_options_file(infile):
    '''Parse a separate options file to list:
        [(namemask, options), ...]
    '''
    results = []
    data = infile.read()
    data = re.sub('/\*.*?\*/', '', data, flags = re.MULTILINE)
    data = re.sub('//.*?$', '', data, flags = re.MULTILINE)
    data = re.sub('#.*?$', '', data, flags = re.MULTILINE)
    for i, line in enumerate(data.split('\n')):
        line = line.strip()
        if not line:
            continue

        parts = line.split(None, 1)

        if len(parts) < 2:
            sys.stderr.write("%s:%d: " % (infile.name, i + 1) +
                             "Option lines should have space between field name and options. " +
                             "Skipping line: '%s'\n" % line)
            continue

        opts = nanopb_pb2.NanoPBOptions()

        try:
            text_format.Merge(parts[1], opts)
        except Exception as e:
            sys.stderr.write("%s:%d: " % (infile.name, i + 1) +
                             "Unparseable option line: '%s'. " % line +
                             "Error: %s\n" % str(e))
            continue
        results.append((parts[0], opts))

    return results

class Globals:
    '''Ugly global variables, should find a good way to pass these.'''
    verbose_options = False
    separate_options = []
    matched_namemasks = set()

def get_nanopb_suboptions(subdesc, options, name):
    '''Get copy of options, and merge information from subdesc.'''
    new_options = nanopb_pb2.NanoPBOptions()
    new_options.CopyFrom(options)

    # Handle options defined in a separate file
    dotname = '.'.join(name.parts)
    for namemask, options in Globals.separate_options:
        if fnmatch(dotname, namemask):
            Globals.matched_namemasks.add(namemask)
            new_options.MergeFrom(options)

    if hasattr(subdesc, 'syntax') and subdesc.syntax == "proto3":
        new_options.proto3 = True

    # Handle options defined in .proto
    if isinstance(subdesc.options, descriptor.FieldOptions):
        ext_type = nanopb_pb2.nanopb
    elif isinstance(subdesc.options, descriptor.FileOptions):
        ext_type = nanopb_pb2.nanopb_fileopt
    elif isinstance(subdesc.options, descriptor.MessageOptions):
        ext_type = nanopb_pb2.nanopb_msgopt
    elif isinstance(subdesc.options, descriptor.EnumOptions):
        ext_type = nanopb_pb2.nanopb_enumopt
    else:
        raise Exception("Unknown options type")

    if subdesc.options.HasExtension(ext_type):
        ext = subdesc.options.Extensions[ext_type]
        new_options.MergeFrom(ext)

    if Globals.verbose_options:
        sys.stderr.write("Options for " + dotname + ": ")
        sys.stderr.write(text_format.MessageToString(new_options) + "\n")

    return new_options


# ---------------------------------------------------------------------------
#                         Command line interface
# ---------------------------------------------------------------------------

import sys
import os.path
from optparse import OptionParser

optparser = OptionParser(
    usage = "Usage: nanopb_generator.py [options] file.pb ...",
    epilog = "Compile file.pb from file.proto by: 'protoc -ofile.pb file.proto'. " +
             "Output will be written to file.pb.h and file.pb.c.")
optparser.add_option("-x", dest="exclude", metavar="FILE", action="append", default=[],
    help="Exclude file from generated #include list.")
optparser.add_option("-e", "--extension", dest="extension", metavar="EXTENSION", default=".pb",
    help="Set extension to use instead of '.pb' for generated files. [default: %default]")
optparser.add_option("-f", "--options-file", dest="options_file", metavar="FILE", default="%s.options",
    help="Set name of a separate generator options file.")
optparser.add_option("-I", "--options-path", dest="options_path", metavar="DIR",
    action="append", default = [],
    help="Search for .options files additionally in this path")
optparser.add_option("-D", "--output-dir", dest="output_dir",
                     metavar="OUTPUTDIR", default=None,
                     help="Output directory of .pb.h and .pb.c files")
optparser.add_option("-Q", "--generated-include-format", dest="genformat",
    metavar="FORMAT", default='#include "%s"\n',
    help="Set format string to use for including other .pb.h files. [default: %default]")
optparser.add_option("-L", "--library-include-format", dest="libformat",
    metavar="FORMAT", default='#include <%s>\n',
    help="Set format string to use for including the nanopb pb.h header. [default: %default]")
optparser.add_option("-T", "--no-timestamp", dest="notimestamp", action="store_true", default=False,
    help="Don't add timestamp to .pb.h and .pb.c preambles")
optparser.add_option("-q", "--quiet", dest="quiet", action="store_true", default=False,
    help="Don't print anything except errors.")
optparser.add_option("-v", "--verbose", dest="verbose", action="store_true", default=False,
    help="Print more information.")
optparser.add_option("-s", dest="settings", metavar="OPTION:VALUE", action="append", default=[],
    help="Set generator option (max_size, max_count etc.).")

def parse_file(filename, fdesc, options):
    '''Parse a single file. Returns a ProtoFile instance.'''
    toplevel_options = nanopb_pb2.NanoPBOptions()
    for s in options.settings:
        text_format.Merge(s, toplevel_options)

    if not fdesc:
        data = open(filename, 'rb').read()
        fdesc = descriptor.FileDescriptorSet.FromString(data).file[0]

    # Check if there is a separate .options file
    had_abspath = False
    try:
        optfilename = options.options_file % os.path.splitext(filename)[0]
    except TypeError:
        # No %s specified, use the filename as-is
        optfilename = options.options_file
        had_abspath = True

    paths = ['.'] + options.options_path
    for p in paths:
        if os.path.isfile(os.path.join(p, optfilename)):
            optfilename = os.path.join(p, optfilename)
            if options.verbose:
                sys.stderr.write('Reading options from ' + optfilename + '\n')
            Globals.separate_options = read_options_file(open(optfilename, "rU"))
            break
    else:
        # If we are given a full filename and it does not exist, give an error.
        # However, don't give error when we automatically look for .options file
        # with the same name as .proto.
        if options.verbose or had_abspath:
            sys.stderr.write('Options file not found: ' + optfilename + '\n')
        Globals.separate_options = []

    Globals.matched_namemasks = set()

    # Parse the file
    file_options = get_nanopb_suboptions(fdesc, toplevel_options, Names([filename]))
    f = ProtoFile(fdesc, file_options)
    f.optfilename = optfilename

    return f

def process_file(filename, fdesc, options, other_files = {}):
    '''Process a single file.
    filename: The full path to the .proto or .pb source file, as string.
    fdesc: The loaded FileDescriptorSet, or None to read from the input file.
    options: Command line options as they come from OptionsParser.

    Returns a dict:
        {'headername': Name of header file,
         'headerdata': Data for the .h header file,
         'sourcename': Name of the source code file,
         'sourcedata': Data for the .c source code file
        }
    '''
    f = parse_file(filename, fdesc, options)

    # Provide dependencies if available
    for dep in f.fdesc.dependency:
        if dep in other_files:
            f.add_dependency(other_files[dep])

    # Decide the file names
    noext = os.path.splitext(filename)[0]
    headername = noext + options.extension + '.h'
    sourcename = noext + options.extension + '.c'
    headerbasename = os.path.basename(headername)

    # List of .proto files that should not be included in the C header file
    # even if they are mentioned in the source .proto.
    excludes = ['nanopb.proto', 'google/protobuf/descriptor.proto'] + options.exclude
    includes = [d for d in f.fdesc.dependency if d not in excludes]

    headerdata = ''.join(f.generate_header(includes, headerbasename, options))
    sourcedata = ''.join(f.generate_source(headerbasename, options))

    # Check if there were any lines in .options that did not match a member
    unmatched = [n for n,o in Globals.separate_options if n not in Globals.matched_namemasks]
    if unmatched and not options.quiet:
        sys.stderr.write("Following patterns in " + f.optfilename + " did not match any fields: "
                         + ', '.join(unmatched) + "\n")
        if not Globals.verbose_options:
            sys.stderr.write("Use  protoc --nanopb-out=-v:.   to see a list of the field names.\n")

    return {'headername': headername, 'headerdata': headerdata,
            'sourcename': sourcename, 'sourcedata': sourcedata}

def main_cli():
    '''Main function when invoked directly from the command line.'''

    options, filenames = optparser.parse_args()

    if not filenames:
        optparser.print_help()
        sys.exit(1)

    if options.quiet:
        options.verbose = False

    if options.output_dir and not os.path.exists(options.output_dir):
        optparser.print_help()
        sys.stderr.write("\noutput_dir does not exist: %s\n" % options.output_dir)
        sys.exit(1)


    Globals.verbose_options = options.verbose
    for filename in filenames:
        results = process_file(filename, None, options)

        base_dir = options.output_dir or ''
        to_write = [
            (os.path.join(base_dir, results['headername']), results['headerdata']),
            (os.path.join(base_dir, results['sourcename']), results['sourcedata']),
        ]

        if not options.quiet:
            paths = " and ".join([x[0] for x in to_write])
            sys.stderr.write("Writing to %s\n" % paths)

        for path, data in to_write:
            with open(path, 'w') as f:
                f.write(data)

def main_plugin():
    '''Main function when invoked as a protoc plugin.'''

    import io, sys
    if sys.platform == "win32":
        import os, msvcrt
        # Set stdin and stdout to binary mode
        msvcrt.setmode(sys.stdin.fileno(), os.O_BINARY)
        msvcrt.setmode(sys.stdout.fileno(), os.O_BINARY)

    data = io.open(sys.stdin.fileno(), "rb").read()

    request = plugin_pb2.CodeGeneratorRequest.FromString(data)

    try:
        # Versions of Python prior to 2.7.3 do not support unicode
        # input to shlex.split(). Try to convert to str if possible.
        params = str(request.parameter)
    except UnicodeEncodeError:
        params = request.parameter

    import shlex
    args = shlex.split(params)
    options, dummy = optparser.parse_args(args)

    Globals.verbose_options = options.verbose

    response = plugin_pb2.CodeGeneratorResponse()

    # Google's protoc does not currently indicate the full path of proto files.
    # Instead always add the main file path to the search dirs, that works for
    # the common case.
    import os.path
    options.options_path.append(os.path.dirname(request.file_to_generate[0]))

    # Process any include files first, in order to have them
    # available as dependencies
    other_files = {}
    for fdesc in request.proto_file:
        other_files[fdesc.name] = parse_file(fdesc.name, fdesc, options)

    for filename in request.file_to_generate:
        for fdesc in request.proto_file:
            if fdesc.name == filename:
                results = process_file(filename, fdesc, options, other_files)

                f = response.file.add()
                f.name = results['headername']
                f.content = results['headerdata']

                f = response.file.add()
                f.name = results['sourcename']
                f.content = results['sourcedata']

    io.open(sys.stdout.fileno(), "wb").write(response.SerializeToString())

if __name__ == '__main__':
    # Check if we are running as a plugin under protoc
    if 'protoc-gen-' in sys.argv[0] or '--protoc-plugin' in sys.argv:
        main_plugin()
    else:
        main_cli()