def length_wrapper(buf, pos):
"""Decode repeat values prefixed with the length"""
length, pos = varint.decode_varint(buf, pos)
end = pos + length
output = []
while pos < end:
value, pos = wrapped_decoder(buf, pos)
output.append(value)
if pos > end:
raise decoder._DecodeError("Invalid Packed Field Length")
return output, pos
def decode_message(buf, typedef=None, pos=0, end=None, group=False):
"""Decode a protobuf message with no length delimiter"""
if end is None:
end = len(buf)
if typedef is None:
typedef = {}
else:
# Don't want to accidentally modify the original
typedef = copy.deepcopy(typedef)
output = {}
while pos < end:
# Read in a field
tag, pos = decoder._DecodeVarint(buf, pos)
try:
field_number, wire_type = wire_format.UnpackTag(tag)
except Exception as exc:
raise (
ValueError,
'Could not read valid tag at pos %d. Ensure it is a valid protobuf message: %s'
% (pos - len(tag), exc), sys.exc_info()[2])
# Convert to str
field_number = str(field_number)
orig_field_number = field_number
field_typedef = None
if field_number in typedef:
field_typedef = typedef[field_number]
else:
field_typedef = {}
field_typedef['type'] = types.wire_type_defaults[wire_type]
field_type = field_typedef['type']
# If field_type is None, its either an unsupported wire type, length delim or group
# length delim we have to try and decode first
field_out = None
if field_type is None:
if wire_type == wire_format.WIRETYPE_LENGTH_DELIMITED:
out, field_type = decode_guess(buf, pos)
if field_type == 'message':
field_out, message_typedef, pos = out
field_typedef['message_typedef'] = message_typedef
else:
field_out, pos = out
elif wire_type == wire_format.WIRETYPE_END_GROUP:
# TODO Should probably match the field_number to START_GROUP
if not group:
raise ValueError("Found END_GROUP before START_GROUP")
# exit out
return output, typedef, pos
else:
raise ValueError(
"Could not find default type for wiretype: %d" % wire_type)
else:
if field_type == 'message':
#TODO probably big enough to factor out
message_typedef = None
# Check for a anonymous type
if 'message_typedef' in field_typedef:
message_typedef = field_typedef['message_typedef']
# Check for type defined by message type name
elif 'message_type_name' in field_typedef:
message_typedef = types.messages[
field_typedef['message_type_name']]
try:
field_out, message_typedef, pos = decode_lendelim_message(
buf, message_typedef, pos)
# Save type definition
field_typedef['message_typedef'] = message_typedef
except Exception as exc:
# If this is the root message just fail
if pos == 0:
raise exc
if field_out is None and 'alt_typedefs' in field_typedef:
# check for an alternative type definition
for alt_field_number, alt_typedef in field_typedef[
'alt_typedefs'].items():
try:
field_out, message_typedef, pos = decode_lendelim_message(
buf, alt_typedef, pos)
except Exception as exc:
pass
if field_out is not None:
# Found working typedef
field_typedef['alt_typedefs'][
alt_field_number] = message_typedef
field_number = field_number + "-" + alt_field_number
break
if field_out is None:
# Still no typedef, try anonymous, and let the error propogate if it fails
field_out, message_typedef, pos = decode_lendelim_message(
buf, {}, pos)
if 'alt_typedefs' in field_typedef:
# get the next higher alt field number
alt_field_number = str(
max(map(int, field_typedef['alt_typedefs'].keys()))
+ 1)
else:
field_typedef['alt_typedefs'] = {}
alt_field_number = '1'
field_typedef['alt_typedefs'][
alt_field_number] = message_typedef
field_number = field_number + "-" + alt_field_number
elif field_type == 'group':
group_typedef = None
# Check for a anonymous type
if 'group_typedef' in field_typedef:
group_typedef = field_typedef['group_typedef']
field_out, group_typedef, pos = decode_group(
buf, group_typedef, pos)
# Save type definition
field_typedef['group_typedef'] = group_typedef
else:
# Verify wiretype matches
if types.wiretypes[field_type] != wire_type:
raise ValueError(
"Invalid wiretype for field number %s. %s is not wiretype %s"
% (field_number, field_type, wire_type))
# Simple type, just look up the decoder
field_out, pos = types.decoders[field_type](buf, pos)
field_typedef['type'] = field_type
if 'name' not in field_typedef:
field_typedef['name'] = ''
field_key = field_number
if '-' not in field_number and 'name' in field_typedef and field_typedef[
'name'] != '':
field_key = field_typedef['name']
# Deal with repeats
if field_key in output:
if isinstance(field_out, list):
if isinstance(output[field_number], list):
output[field_key] += field_out
else:
output[field_key] = field_out.append(output[field_key])
else:
if isinstance(output[field_number], list):
output[field_key].append(field_out)
else:
output[field_key] = [output[field_key], field_out]
else:
output[field_key] = field_out
typedef[orig_field_number] = field_typedef
if pos > end:
raise decoder._DecodeError("Invalid Message Length")
# Should never hit here as a group
if group:
raise ValueError("Got START_GROUP with no END_GROUP.")
return output, typedef, pos