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# Copyright (C) 2006-2007 Jelmer Vernooij <jelmer@jelmer.uk>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU Lesser General Public License as published by
# the Free Software Foundation; either version 2.1 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
"""Marshalling for the svn_ra protocol."""
class literal:
"""A protocol literal."""
def __init__(self, txt):
self.txt = txt
def __str__(self):
return self.txt
def __repr__(self):
return self.txt
# 1. Syntactic structure
# ----------------------
#
# The Subversion protocol is specified in terms of the following
# syntactic elements, specified using ABNF [RFC 2234]:
#
# item = word / number / string / list
# word = ALPHA *(ALPHA / DIGIT / "-") space
# number = 1*DIGIT space
# string = 1*DIGIT ":" *OCTET space
# ; digits give the byte count of the *OCTET portion
# list = "(" space *item ")" space
# space = 1*(SP / LF)
#
class MarshallError(Exception):
"""A Marshall error."""
class NeedMoreData(MarshallError):
"""More data needed."""
def marshall(x):
"""Marshall a Python data item.
:param x: Data item
:return: encoded byte string
"""
if isinstance(x, int):
return ("%d " % x).encode("ascii")
elif isinstance(x, (list, tuple)):
return b"( " + bytes().join(map(marshall, x)) + b") "
elif isinstance(x, literal):
return ("%s " % x).encode("ascii")
elif isinstance(x, bytes):
return ("%d:" % len(x)).encode("ascii") + x + b" "
elif isinstance(x, str):
x = x.encode("utf-8")
return ("%d:" % len(x)).encode("ascii") + x + b" "
elif isinstance(x, bool):
if x == True:
return b"true "
elif x == False:
return b"false "
raise MarshallError("Unable to marshall type %s" % x)
def unmarshall(x):
"""Unmarshall the next item from a buffer.
:param x: Bytes to parse
:return: tuple with unpacked item and remaining bytes
"""
whitespace = frozenset(b'\n ')
if len(x) == 0:
raise NeedMoreData("Not enough data")
if x[0:1] == b"(": # list follows
if len(x) <= 1:
raise NeedMoreData("Missing whitespace")
if x[1:2] != b" ":
raise MarshallError("missing whitespace after list start")
x = x[2:]
ret = []
try:
while x[0:1] != b")":
(x, n) = unmarshall(x)
ret.append(n)
except IndexError:
raise NeedMoreData("List not terminated")
if len(x) <= 1:
raise NeedMoreData("Missing whitespace")
if not x[1] in whitespace:
raise MarshallError("Expected space, got '%c'" % x[1])
return (x[2:], ret)
elif x[0:1].isdigit():
num = bytearray()
# Check if this is a string or a number
while x[:1].isdigit():
num.append(x[0])
x = x[1:]
num = int(num)
if x[0] in whitespace:
return (x[1:], num)
elif x[0:1] == b":":
if len(x) < num:
raise NeedMoreData("Expected string of length %r" % num)
return (x[num+2:], x[1:num+1])
elif not x:
raise MarshallError("Expected whitespace, got end of string.")
else:
raise MarshallError("Expected whitespace or ':', got '%c'" % x[0])
elif x[:1].isalpha():
ret = bytearray()
# Parse literal
try:
while x[:1].isalpha() or x[:1].isdigit() or x[0:1] == b'-':
ret.append(x[0])
x = x[1:]
except IndexError:
raise NeedMoreData("Expected literal")
if not x:
raise MarshallError("Expected whitespace, got end of string.")
if not x[0] in whitespace:
raise MarshallError("Expected whitespace, got '%c'" % x[0])
return (x[1:], ret.decode("ascii"))
else:
raise MarshallError("Unexpected character '%c'" % x[0])
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