blob: 6f1e3c8b725ea2f90b27ad62714de4d4df24a94c [file] [log] [blame]
# Protocol Buffers - Google's data interchange format
# Copyright 2008 Google Inc. All rights reserved.
# https://developers.google.com/protocol-buffers/
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above
# copyright notice, this list of conditions and the following disclaimer
# in the documentation and/or other materials provided with the
# distribution.
# * Neither the name of Google Inc. nor the names of its
# contributors may be used to endorse or promote products derived from
# this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
"""Contains routines for printing protocol messages in text format.
Simple usage example:
# Create a proto object and serialize it to a text proto string.
message = my_proto_pb2.MyMessage(foo='bar')
text_proto = text_format.MessageToString(message)
# Parse a text proto string.
message = text_format.Parse(text_proto, my_proto_pb2.MyMessage())
"""
__author__ = 'kenton@google.com (Kenton Varda)'
import io
import re
import six
if six.PY3:
long = int
from google.protobuf.internal import type_checkers
from google.protobuf import descriptor
from google.protobuf import text_encoding
__all__ = ['MessageToString', 'PrintMessage', 'PrintField',
'PrintFieldValue', 'Merge']
_INTEGER_CHECKERS = (type_checkers.Uint32ValueChecker(),
type_checkers.Int32ValueChecker(),
type_checkers.Uint64ValueChecker(),
type_checkers.Int64ValueChecker())
_FLOAT_INFINITY = re.compile('-?inf(?:inity)?f?', re.IGNORECASE)
_FLOAT_NAN = re.compile('nanf?', re.IGNORECASE)
_FLOAT_TYPES = frozenset([descriptor.FieldDescriptor.CPPTYPE_FLOAT,
descriptor.FieldDescriptor.CPPTYPE_DOUBLE])
_QUOTES = frozenset(("'", '"'))
class Error(Exception):
"""Top-level module error for text_format."""
class ParseError(Error):
"""Thrown in case of text parsing error."""
class TextWriter(object):
def __init__(self, as_utf8):
if six.PY2:
self._writer = io.BytesIO()
else:
self._writer = io.StringIO()
def write(self, val):
if six.PY2:
if isinstance(val, six.text_type):
val = val.encode('utf-8')
return self._writer.write(val)
def close(self):
return self._writer.close()
def getvalue(self):
return self._writer.getvalue()
def MessageToString(message, as_utf8=False, as_one_line=False,
pointy_brackets=False, use_index_order=False,
float_format=None, use_field_number=False):
"""Convert protobuf message to text format.
Floating point values can be formatted compactly with 15 digits of
precision (which is the most that IEEE 754 "double" can guarantee)
using float_format='.15g'. To ensure that converting to text and back to a
proto will result in an identical value, float_format='.17g' should be used.
Args:
message: The protocol buffers message.
as_utf8: Produce text output in UTF8 format.
as_one_line: Don't introduce newlines between fields.
pointy_brackets: If True, use angle brackets instead of curly braces for
nesting.
use_index_order: If True, print fields of a proto message using the order
defined in source code instead of the field number. By default, use the
field number order.
float_format: If set, use this to specify floating point number formatting
(per the "Format Specification Mini-Language"); otherwise, str() is used.
use_field_number: If True, print field numbers instead of names.
Returns:
A string of the text formatted protocol buffer message.
"""
out = TextWriter(as_utf8)
printer = _Printer(out, 0, as_utf8, as_one_line,
pointy_brackets, use_index_order, float_format,
use_field_number)
printer.PrintMessage(message)
result = out.getvalue()
out.close()
if as_one_line:
return result.rstrip()
return result
def _IsMapEntry(field):
return (field.type == descriptor.FieldDescriptor.TYPE_MESSAGE and
field.message_type.has_options and
field.message_type.GetOptions().map_entry)
def PrintMessage(message, out, indent=0, as_utf8=False, as_one_line=False,
pointy_brackets=False, use_index_order=False,
float_format=None, use_field_number=False):
printer = _Printer(out, indent, as_utf8, as_one_line,
pointy_brackets, use_index_order, float_format,
use_field_number)
printer.PrintMessage(message)
def PrintField(field, value, out, indent=0, as_utf8=False, as_one_line=False,
pointy_brackets=False, use_index_order=False, float_format=None):
"""Print a single field name/value pair."""
printer = _Printer(out, indent, as_utf8, as_one_line,
pointy_brackets, use_index_order, float_format)
printer.PrintField(field, value)
def PrintFieldValue(field, value, out, indent=0, as_utf8=False,
as_one_line=False, pointy_brackets=False,
use_index_order=False,
float_format=None):
"""Print a single field value (not including name)."""
printer = _Printer(out, indent, as_utf8, as_one_line,
pointy_brackets, use_index_order, float_format)
printer.PrintFieldValue(field, value)
class _Printer(object):
"""Text format printer for protocol message."""
def __init__(self, out, indent=0, as_utf8=False, as_one_line=False,
pointy_brackets=False, use_index_order=False, float_format=None,
use_field_number=False):
"""Initialize the Printer.
Floating point values can be formatted compactly with 15 digits of
precision (which is the most that IEEE 754 "double" can guarantee)
using float_format='.15g'. To ensure that converting to text and back to a
proto will result in an identical value, float_format='.17g' should be used.
Args:
out: To record the text format result.
indent: The indent level for pretty print.
as_utf8: Produce text output in UTF8 format.
as_one_line: Don't introduce newlines between fields.
pointy_brackets: If True, use angle brackets instead of curly braces for
nesting.
use_index_order: If True, print fields of a proto message using the order
defined in source code instead of the field number. By default, use the
field number order.
float_format: If set, use this to specify floating point number formatting
(per the "Format Specification Mini-Language"); otherwise, str() is
used.
use_field_number: If True, print field numbers instead of names.
"""
self.out = out
self.indent = indent
self.as_utf8 = as_utf8
self.as_one_line = as_one_line
self.pointy_brackets = pointy_brackets
self.use_index_order = use_index_order
self.float_format = float_format
self.use_field_number = use_field_number
def PrintMessage(self, message):
"""Convert protobuf message to text format.
Args:
message: The protocol buffers message.
"""
fields = message.ListFields()
if self.use_index_order:
fields.sort(key=lambda x: x[0].index)
for field, value in fields:
if _IsMapEntry(field):
for key in sorted(value):
# This is slow for maps with submessage entires because it copies the
# entire tree. Unfortunately this would take significant refactoring
# of this file to work around.
#
# TODO(haberman): refactor and optimize if this becomes an issue.
entry_submsg = field.message_type._concrete_class(
key=key, value=value[key])
self.PrintField(field, entry_submsg)
elif field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
for element in value:
self.PrintField(field, element)
else:
self.PrintField(field, value)
def PrintField(self, field, value):
"""Print a single field name/value pair."""
out = self.out
out.write(' ' * self.indent)
if self.use_field_number:
out.write(str(field.number))
else:
if field.is_extension:
out.write('[')
if (field.containing_type.GetOptions().message_set_wire_format and
field.type == descriptor.FieldDescriptor.TYPE_MESSAGE and
field.label == descriptor.FieldDescriptor.LABEL_OPTIONAL):
out.write(field.message_type.full_name)
else:
out.write(field.full_name)
out.write(']')
elif field.type == descriptor.FieldDescriptor.TYPE_GROUP:
# For groups, use the capitalized name.
out.write(field.message_type.name)
else:
out.write(field.name)
if field.cpp_type != descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
# The colon is optional in this case, but our cross-language golden files
# don't include it.
out.write(': ')
self.PrintFieldValue(field, value)
if self.as_one_line:
out.write(' ')
else:
out.write('\n')
def PrintFieldValue(self, field, value):
"""Print a single field value (not including name).
For repeated fields, the value should be a single element.
Args:
field: The descriptor of the field to be printed.
value: The value of the field.
"""
out = self.out
if self.pointy_brackets:
openb = '<'
closeb = '>'
else:
openb = '{'
closeb = '}'
if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
if self.as_one_line:
out.write(' %s ' % openb)
self.PrintMessage(value)
out.write(closeb)
else:
out.write(' %s\n' % openb)
self.indent += 2
self.PrintMessage(value)
self.indent -= 2
out.write(' ' * self.indent + closeb)
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_ENUM:
enum_value = field.enum_type.values_by_number.get(value, None)
if enum_value is not None:
out.write(enum_value.name)
else:
out.write(str(value))
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_STRING:
out.write('\"')
if isinstance(value, six.text_type):
out_value = value.encode('utf-8')
else:
out_value = value
if field.type == descriptor.FieldDescriptor.TYPE_BYTES:
# We need to escape non-UTF8 chars in TYPE_BYTES field.
out_as_utf8 = False
else:
out_as_utf8 = self.as_utf8
out.write(text_encoding.CEscape(out_value, out_as_utf8))
out.write('\"')
elif field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_BOOL:
if value:
out.write('true')
else:
out.write('false')
elif field.cpp_type in _FLOAT_TYPES and self.float_format is not None:
out.write('{1:{0}}'.format(self.float_format, value))
else:
out.write(str(value))
def Parse(text, message,
allow_unknown_extension=False, allow_field_number=False):
"""Parses an text representation of a protocol message into a message.
Args:
text: Message text representation.
message: A protocol buffer message to merge into.
allow_unknown_extension: if True, skip over missing extensions and keep
parsing
allow_field_number: if True, both field number and field name are allowed.
Returns:
The same message passed as argument.
Raises:
ParseError: On text parsing problems.
"""
if not isinstance(text, str):
text = text.decode('utf-8')
return ParseLines(text.split('\n'), message, allow_unknown_extension,
allow_field_number)
def Merge(text, message, allow_unknown_extension=False,
allow_field_number=False):
"""Parses an text representation of a protocol message into a message.
Like Parse(), but allows repeated values for a non-repeated field, and uses
the last one.
Args:
text: Message text representation.
message: A protocol buffer message to merge into.
allow_unknown_extension: if True, skip over missing extensions and keep
parsing
allow_field_number: if True, both field number and field name are allowed.
Returns:
The same message passed as argument.
Raises:
ParseError: On text parsing problems.
"""
return MergeLines(text.split('\n'), message, allow_unknown_extension,
allow_field_number)
def ParseLines(lines, message, allow_unknown_extension=False,
allow_field_number=False):
"""Parses an text representation of a protocol message into a message.
Args:
lines: An iterable of lines of a message's text representation.
message: A protocol buffer message to merge into.
allow_unknown_extension: if True, skip over missing extensions and keep
parsing
allow_field_number: if True, both field number and field name are allowed.
Returns:
The same message passed as argument.
Raises:
ParseError: On text parsing problems.
"""
parser = _Parser(allow_unknown_extension, allow_field_number)
return parser.ParseLines(lines, message)
def MergeLines(lines, message, allow_unknown_extension=False,
allow_field_number=False):
"""Parses an text representation of a protocol message into a message.
Args:
lines: An iterable of lines of a message's text representation.
message: A protocol buffer message to merge into.
allow_unknown_extension: if True, skip over missing extensions and keep
parsing
allow_field_number: if True, both field number and field name are allowed.
Returns:
The same message passed as argument.
Raises:
ParseError: On text parsing problems.
"""
parser = _Parser(allow_unknown_extension, allow_field_number)
return parser.MergeLines(lines, message)
class _Parser(object):
"""Text format parser for protocol message."""
def __init__(self, allow_unknown_extension=False, allow_field_number=False):
self.allow_unknown_extension = allow_unknown_extension
self.allow_field_number = allow_field_number
def ParseFromString(self, text, message):
"""Parses an text representation of a protocol message into a message."""
if not isinstance(text, str):
text = text.decode('utf-8')
return self.ParseLines(text.split('\n'), message)
def ParseLines(self, lines, message):
"""Parses an text representation of a protocol message into a message."""
self._allow_multiple_scalars = False
self._ParseOrMerge(lines, message)
return message
def MergeFromString(self, text, message):
"""Merges an text representation of a protocol message into a message."""
return self._MergeLines(text.split('\n'), message)
def MergeLines(self, lines, message):
"""Merges an text representation of a protocol message into a message."""
self._allow_multiple_scalars = True
self._ParseOrMerge(lines, message)
return message
def _ParseOrMerge(self, lines, message):
"""Converts an text representation of a protocol message into a message.
Args:
lines: Lines of a message's text representation.
message: A protocol buffer message to merge into.
Raises:
ParseError: On text parsing problems.
"""
tokenizer = _Tokenizer(lines)
while not tokenizer.AtEnd():
self._MergeField(tokenizer, message)
def _MergeField(self, tokenizer, message):
"""Merges a single protocol message field into a message.
Args:
tokenizer: A tokenizer to parse the field name and values.
message: A protocol message to record the data.
Raises:
ParseError: In case of text parsing problems.
"""
message_descriptor = message.DESCRIPTOR
if (hasattr(message_descriptor, 'syntax') and
message_descriptor.syntax == 'proto3'):
# Proto3 doesn't represent presence so we can't test if multiple
# scalars have occurred. We have to allow them.
self._allow_multiple_scalars = True
if tokenizer.TryConsume('['):
name = [tokenizer.ConsumeIdentifier()]
while tokenizer.TryConsume('.'):
name.append(tokenizer.ConsumeIdentifier())
name = '.'.join(name)
if not message_descriptor.is_extendable:
raise tokenizer.ParseErrorPreviousToken(
'Message type "%s" does not have extensions.' %
message_descriptor.full_name)
# pylint: disable=protected-access
field = message.Extensions._FindExtensionByName(name)
# pylint: enable=protected-access
if not field:
if self.allow_unknown_extension:
field = None
else:
raise tokenizer.ParseErrorPreviousToken(
'Extension "%s" not registered.' % name)
elif message_descriptor != field.containing_type:
raise tokenizer.ParseErrorPreviousToken(
'Extension "%s" does not extend message type "%s".' % (
name, message_descriptor.full_name))
tokenizer.Consume(']')
else:
name = tokenizer.ConsumeIdentifier()
if self.allow_field_number and name.isdigit():
number = ParseInteger(name, True, True)
field = message_descriptor.fields_by_number.get(number, None)
if not field and message_descriptor.is_extendable:
field = message.Extensions._FindExtensionByNumber(number)
else:
field = message_descriptor.fields_by_name.get(name, None)
# Group names are expected to be capitalized as they appear in the
# .proto file, which actually matches their type names, not their field
# names.
if not field:
field = message_descriptor.fields_by_name.get(name.lower(), None)
if field and field.type != descriptor.FieldDescriptor.TYPE_GROUP:
field = None
if (field and field.type == descriptor.FieldDescriptor.TYPE_GROUP and
field.message_type.name != name):
field = None
if not field:
raise tokenizer.ParseErrorPreviousToken(
'Message type "%s" has no field named "%s".' % (
message_descriptor.full_name, name))
if field:
if not self._allow_multiple_scalars and field.containing_oneof:
# Check if there's a different field set in this oneof.
# Note that we ignore the case if the same field was set before, and we
# apply _allow_multiple_scalars to non-scalar fields as well.
which_oneof = message.WhichOneof(field.containing_oneof.name)
if which_oneof is not None and which_oneof != field.name:
raise tokenizer.ParseErrorPreviousToken(
'Field "%s" is specified along with field "%s", another member '
'of oneof "%s" for message type "%s".' % (
field.name, which_oneof, field.containing_oneof.name,
message_descriptor.full_name))
if field.cpp_type == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
tokenizer.TryConsume(':')
merger = self._MergeMessageField
else:
tokenizer.Consume(':')
merger = self._MergeScalarField
if (field.label == descriptor.FieldDescriptor.LABEL_REPEATED
and tokenizer.TryConsume('[')):
# Short repeated format, e.g. "foo: [1, 2, 3]"
while True:
merger(tokenizer, message, field)
if tokenizer.TryConsume(']'): break
tokenizer.Consume(',')
else:
merger(tokenizer, message, field)
else: # Proto field is unknown.
assert self.allow_unknown_extension
_SkipFieldContents(tokenizer)
# For historical reasons, fields may optionally be separated by commas or
# semicolons.
if not tokenizer.TryConsume(','):
tokenizer.TryConsume(';')
def _MergeMessageField(self, tokenizer, message, field):
"""Merges a single scalar field into a message.
Args:
tokenizer: A tokenizer to parse the field value.
message: The message of which field is a member.
field: The descriptor of the field to be merged.
Raises:
ParseError: In case of text parsing problems.
"""
is_map_entry = _IsMapEntry(field)
if tokenizer.TryConsume('<'):
end_token = '>'
else:
tokenizer.Consume('{')
end_token = '}'
if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
if field.is_extension:
sub_message = message.Extensions[field].add()
elif is_map_entry:
# pylint: disable=protected-access
sub_message = field.message_type._concrete_class()
else:
sub_message = getattr(message, field.name).add()
else:
if field.is_extension:
sub_message = message.Extensions[field]
else:
sub_message = getattr(message, field.name)
sub_message.SetInParent()
while not tokenizer.TryConsume(end_token):
if tokenizer.AtEnd():
raise tokenizer.ParseErrorPreviousToken('Expected "%s".' % (end_token,))
self._MergeField(tokenizer, sub_message)
if is_map_entry:
value_cpptype = field.message_type.fields_by_name['value'].cpp_type
if value_cpptype == descriptor.FieldDescriptor.CPPTYPE_MESSAGE:
value = getattr(message, field.name)[sub_message.key]
value.MergeFrom(sub_message.value)
else:
getattr(message, field.name)[sub_message.key] = sub_message.value
def _MergeScalarField(self, tokenizer, message, field):
"""Merges a single scalar field into a message.
Args:
tokenizer: A tokenizer to parse the field value.
message: A protocol message to record the data.
field: The descriptor of the field to be merged.
Raises:
ParseError: In case of text parsing problems.
RuntimeError: On runtime errors.
"""
_ = self.allow_unknown_extension
value = None
if field.type in (descriptor.FieldDescriptor.TYPE_INT32,
descriptor.FieldDescriptor.TYPE_SINT32,
descriptor.FieldDescriptor.TYPE_SFIXED32):
value = tokenizer.ConsumeInt32()
elif field.type in (descriptor.FieldDescriptor.TYPE_INT64,
descriptor.FieldDescriptor.TYPE_SINT64,
descriptor.FieldDescriptor.TYPE_SFIXED64):
value = tokenizer.ConsumeInt64()
elif field.type in (descriptor.FieldDescriptor.TYPE_UINT32,
descriptor.FieldDescriptor.TYPE_FIXED32):
value = tokenizer.ConsumeUint32()
elif field.type in (descriptor.FieldDescriptor.TYPE_UINT64,
descriptor.FieldDescriptor.TYPE_FIXED64):
value = tokenizer.ConsumeUint64()
elif field.type in (descriptor.FieldDescriptor.TYPE_FLOAT,
descriptor.FieldDescriptor.TYPE_DOUBLE):
value = tokenizer.ConsumeFloat()
elif field.type == descriptor.FieldDescriptor.TYPE_BOOL:
value = tokenizer.ConsumeBool()
elif field.type == descriptor.FieldDescriptor.TYPE_STRING:
value = tokenizer.ConsumeString()
elif field.type == descriptor.FieldDescriptor.TYPE_BYTES:
value = tokenizer.ConsumeByteString()
elif field.type == descriptor.FieldDescriptor.TYPE_ENUM:
value = tokenizer.ConsumeEnum(field)
else:
raise RuntimeError('Unknown field type %d' % field.type)
if field.label == descriptor.FieldDescriptor.LABEL_REPEATED:
if field.is_extension:
message.Extensions[field].append(value)
else:
getattr(message, field.name).append(value)
else:
if field.is_extension:
if not self._allow_multiple_scalars and message.HasExtension(field):
raise tokenizer.ParseErrorPreviousToken(
'Message type "%s" should not have multiple "%s" extensions.' %
(message.DESCRIPTOR.full_name, field.full_name))
else:
message.Extensions[field] = value
else:
if not self._allow_multiple_scalars and message.HasField(field.name):
raise tokenizer.ParseErrorPreviousToken(
'Message type "%s" should not have multiple "%s" fields.' %
(message.DESCRIPTOR.full_name, field.name))
else:
setattr(message, field.name, value)
def _SkipFieldContents(tokenizer):
"""Skips over contents (value or message) of a field.
Args:
tokenizer: A tokenizer to parse the field name and values.
"""
# Try to guess the type of this field.
# If this field is not a message, there should be a ":" between the
# field name and the field value and also the field value should not
# start with "{" or "<" which indicates the beginning of a message body.
# If there is no ":" or there is a "{" or "<" after ":", this field has
# to be a message or the input is ill-formed.
if tokenizer.TryConsume(':') and not tokenizer.LookingAt(
'{') and not tokenizer.LookingAt('<'):
_SkipFieldValue(tokenizer)
else:
_SkipFieldMessage(tokenizer)
def _SkipField(tokenizer):
"""Skips over a complete field (name and value/message).
Args:
tokenizer: A tokenizer to parse the field name and values.
"""
if tokenizer.TryConsume('['):
# Consume extension name.
tokenizer.ConsumeIdentifier()
while tokenizer.TryConsume('.'):
tokenizer.ConsumeIdentifier()
tokenizer.Consume(']')
else:
tokenizer.ConsumeIdentifier()
_SkipFieldContents(tokenizer)
# For historical reasons, fields may optionally be separated by commas or
# semicolons.
if not tokenizer.TryConsume(','):
tokenizer.TryConsume(';')
def _SkipFieldMessage(tokenizer):
"""Skips over a field message.
Args:
tokenizer: A tokenizer to parse the field name and values.
"""
if tokenizer.TryConsume('<'):
delimiter = '>'
else:
tokenizer.Consume('{')
delimiter = '}'
while not tokenizer.LookingAt('>') and not tokenizer.LookingAt('}'):
_SkipField(tokenizer)
tokenizer.Consume(delimiter)
def _SkipFieldValue(tokenizer):
"""Skips over a field value.
Args:
tokenizer: A tokenizer to parse the field name and values.
Raises:
ParseError: In case an invalid field value is found.
"""
# String/bytes tokens can come in multiple adjacent string literals.
# If we can consume one, consume as many as we can.
if tokenizer.TryConsumeByteString():
while tokenizer.TryConsumeByteString():
pass
return
if (not tokenizer.TryConsumeIdentifier() and
not tokenizer.TryConsumeInt64() and
not tokenizer.TryConsumeUint64() and
not tokenizer.TryConsumeFloat()):
raise ParseError('Invalid field value: ' + tokenizer.token)
class _Tokenizer(object):
"""Protocol buffer text representation tokenizer.
This class handles the lower level string parsing by splitting it into
meaningful tokens.
It was directly ported from the Java protocol buffer API.
"""
_WHITESPACE = re.compile('(\\s|(#.*$))+', re.MULTILINE)
_TOKEN = re.compile('|'.join([
r'[a-zA-Z_][0-9a-zA-Z_+-]*', # an identifier
r'([0-9+-]|(\.[0-9]))[0-9a-zA-Z_.+-]*', # a number
] + [ # quoted str for each quote mark
r'{qt}([^{qt}\n\\]|\\.)*({qt}|\\?$)'.format(qt=mark) for mark in _QUOTES
]))
_IDENTIFIER = re.compile(r'\w+')
def __init__(self, lines):
self._position = 0
self._line = -1
self._column = 0
self._token_start = None
self.token = ''
self._lines = iter(lines)
self._current_line = ''
self._previous_line = 0
self._previous_column = 0
self._more_lines = True
self._SkipWhitespace()
self.NextToken()
def LookingAt(self, token):
return self.token == token
def AtEnd(self):
"""Checks the end of the text was reached.
Returns:
True iff the end was reached.
"""
return not self.token
def _PopLine(self):
while len(self._current_line) <= self._column:
try:
self._current_line = next(self._lines)
except StopIteration:
self._current_line = ''
self._more_lines = False
return
else:
self._line += 1
self._column = 0
def _SkipWhitespace(self):
while True:
self._PopLine()
match = self._WHITESPACE.match(self._current_line, self._column)
if not match:
break
length = len(match.group(0))
self._column += length
def TryConsume(self, token):
"""Tries to consume a given piece of text.
Args:
token: Text to consume.
Returns:
True iff the text was consumed.
"""
if self.token == token:
self.NextToken()
return True
return False
def Consume(self, token):
"""Consumes a piece of text.
Args:
token: Text to consume.
Raises:
ParseError: If the text couldn't be consumed.
"""
if not self.TryConsume(token):
raise self._ParseError('Expected "%s".' % token)
def TryConsumeIdentifier(self):
try:
self.ConsumeIdentifier()
return True
except ParseError:
return False
def ConsumeIdentifier(self):
"""Consumes protocol message field identifier.
Returns:
Identifier string.
Raises:
ParseError: If an identifier couldn't be consumed.
"""
result = self.token
if not self._IDENTIFIER.match(result):
raise self._ParseError('Expected identifier.')
self.NextToken()
return result
def ConsumeInt32(self):
"""Consumes a signed 32bit integer number.
Returns:
The integer parsed.
Raises:
ParseError: If a signed 32bit integer couldn't be consumed.
"""
try:
result = ParseInteger(self.token, is_signed=True, is_long=False)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def ConsumeUint32(self):
"""Consumes an unsigned 32bit integer number.
Returns:
The integer parsed.
Raises:
ParseError: If an unsigned 32bit integer couldn't be consumed.
"""
try:
result = ParseInteger(self.token, is_signed=False, is_long=False)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def TryConsumeInt64(self):
try:
self.ConsumeInt64()
return True
except ParseError:
return False
def ConsumeInt64(self):
"""Consumes a signed 64bit integer number.
Returns:
The integer parsed.
Raises:
ParseError: If a signed 64bit integer couldn't be consumed.
"""
try:
result = ParseInteger(self.token, is_signed=True, is_long=True)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def TryConsumeUint64(self):
try:
self.ConsumeUint64()
return True
except ParseError:
return False
def ConsumeUint64(self):
"""Consumes an unsigned 64bit integer number.
Returns:
The integer parsed.
Raises:
ParseError: If an unsigned 64bit integer couldn't be consumed.
"""
try:
result = ParseInteger(self.token, is_signed=False, is_long=True)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def TryConsumeFloat(self):
try:
self.ConsumeFloat()
return True
except ParseError:
return False
def ConsumeFloat(self):
"""Consumes an floating point number.
Returns:
The number parsed.
Raises:
ParseError: If a floating point number couldn't be consumed.
"""
try:
result = ParseFloat(self.token)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def ConsumeBool(self):
"""Consumes a boolean value.
Returns:
The bool parsed.
Raises:
ParseError: If a boolean value couldn't be consumed.
"""
try:
result = ParseBool(self.token)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def TryConsumeByteString(self):
try:
self.ConsumeByteString()
return True
except ParseError:
return False
def ConsumeString(self):
"""Consumes a string value.
Returns:
The string parsed.
Raises:
ParseError: If a string value couldn't be consumed.
"""
the_bytes = self.ConsumeByteString()
try:
return six.text_type(the_bytes, 'utf-8')
except UnicodeDecodeError as e:
raise self._StringParseError(e)
def ConsumeByteString(self):
"""Consumes a byte array value.
Returns:
The array parsed (as a string).
Raises:
ParseError: If a byte array value couldn't be consumed.
"""
the_list = [self._ConsumeSingleByteString()]
while self.token and self.token[0] in _QUOTES:
the_list.append(self._ConsumeSingleByteString())
return b''.join(the_list)
def _ConsumeSingleByteString(self):
"""Consume one token of a string literal.
String literals (whether bytes or text) can come in multiple adjacent
tokens which are automatically concatenated, like in C or Python. This
method only consumes one token.
Returns:
The token parsed.
Raises:
ParseError: When the wrong format data is found.
"""
text = self.token
if len(text) < 1 or text[0] not in _QUOTES:
raise self._ParseError('Expected string but found: %r' % (text,))
if len(text) < 2 or text[-1] != text[0]:
raise self._ParseError('String missing ending quote: %r' % (text,))
try:
result = text_encoding.CUnescape(text[1:-1])
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def ConsumeEnum(self, field):
try:
result = ParseEnum(field, self.token)
except ValueError as e:
raise self._ParseError(str(e))
self.NextToken()
return result
def ParseErrorPreviousToken(self, message):
"""Creates and *returns* a ParseError for the previously read token.
Args:
message: A message to set for the exception.
Returns:
A ParseError instance.
"""
return ParseError('%d:%d : %s' % (
self._previous_line + 1, self._previous_column + 1, message))
def _ParseError(self, message):
"""Creates and *returns* a ParseError for the current token."""
return ParseError('%d:%d : %s' % (
self._line + 1, self._column + 1, message))
def _StringParseError(self, e):
return self._ParseError('Couldn\'t parse string: ' + str(e))
def NextToken(self):
"""Reads the next meaningful token."""
self._previous_line = self._line
self._previous_column = self._column
self._column += len(self.token)
self._SkipWhitespace()
if not self._more_lines:
self.token = ''
return
match = self._TOKEN.match(self._current_line, self._column)
if match:
token = match.group(0)
self.token = token
else:
self.token = self._current_line[self._column]
def ParseInteger(text, is_signed=False, is_long=False):
"""Parses an integer.
Args:
text: The text to parse.
is_signed: True if a signed integer must be parsed.
is_long: True if a long integer must be parsed.
Returns:
The integer value.
Raises:
ValueError: Thrown Iff the text is not a valid integer.
"""
# Do the actual parsing. Exception handling is propagated to caller.
try:
# We force 32-bit values to int and 64-bit values to long to make
# alternate implementations where the distinction is more significant
# (e.g. the C++ implementation) simpler.
if is_long:
result = long(text, 0)
else:
result = int(text, 0)
except ValueError:
raise ValueError('Couldn\'t parse integer: %s' % text)
# Check if the integer is sane. Exceptions handled by callers.
checker = _INTEGER_CHECKERS[2 * int(is_long) + int(is_signed)]
checker.CheckValue(result)
return result
def ParseFloat(text):
"""Parse a floating point number.
Args:
text: Text to parse.
Returns:
The number parsed.
Raises:
ValueError: If a floating point number couldn't be parsed.
"""
try:
# Assume Python compatible syntax.
return float(text)
except ValueError:
# Check alternative spellings.
if _FLOAT_INFINITY.match(text):
if text[0] == '-':
return float('-inf')
else:
return float('inf')
elif _FLOAT_NAN.match(text):
return float('nan')
else:
# assume '1.0f' format
try:
return float(text.rstrip('f'))
except ValueError:
raise ValueError('Couldn\'t parse float: %s' % text)
def ParseBool(text):
"""Parse a boolean value.
Args:
text: Text to parse.
Returns:
Boolean values parsed
Raises:
ValueError: If text is not a valid boolean.
"""
if text in ('true', 't', '1'):
return True
elif text in ('false', 'f', '0'):
return False
else:
raise ValueError('Expected "true" or "false".')
def ParseEnum(field, value):
"""Parse an enum value.
The value can be specified by a number (the enum value), or by
a string literal (the enum name).
Args:
field: Enum field descriptor.
value: String value.
Returns:
Enum value number.
Raises:
ValueError: If the enum value could not be parsed.
"""
enum_descriptor = field.enum_type
try:
number = int(value, 0)
except ValueError:
# Identifier.
enum_value = enum_descriptor.values_by_name.get(value, None)
if enum_value is None:
raise ValueError(
'Enum type "%s" has no value named %s.' % (
enum_descriptor.full_name, value))
else:
# Numeric value.
enum_value = enum_descriptor.values_by_number.get(number, None)
if enum_value is None:
raise ValueError(
'Enum type "%s" has no value with number %d.' % (
enum_descriptor.full_name, number))
return enum_value.number