xenu_nntp/lib/xenu_nntp/mbox.py
2025-01-06 10:11:09 -05:00

131 lines
3.4 KiB
Python

from xenu_nntp.message import Message
class MBoxReaderError(Exception):
pass
class MBoxReaderBuffer():
def __init__(self):
self.lines = [None, None, None, None]
def add(self, line: str):
if self.lines[0] is None:
self.lines[0] = line
elif self.lines[1] is None:
self.lines[1] = line
elif self.lines[2] is None:
self.lines[2] = line
elif self.lines[3] is None:
self.lines[3] = line
else:
self.lines[0] = self.lines[1]
self.lines[1] = self.lines[2]
self.lines[2] = self.lines[3]
self.lines[3] = line
def is_empty_line(self, line):
return self.lines[line] == '\n'
def is_from_line(self, line):
return self.lines[line][0:5] == 'From '
def is_header_line(self, line):
return Message.RE_HEADER.match(self.lines[line]) is not None
def is_start(self):
if self.lines[0] is None or self.lines[1] is None:
return False
if self.is_from_line(0) \
and self.is_header_line(1) \
and self.lines[2] is None \
and self.lines[3] is None:
return True
elif self.is_empty_line(0) \
and self.is_empty_line(1) \
and self.is_from_line(2) \
and self.is_header_line(3):
return True
else:
return False
def is_end(self):
return self.lines[0] is not None \
and self.is_empty_line(1) \
and self.is_empty_line(2) \
and self.is_from_line(3)
class MBoxReader():
__slots__ = 'path', 'fh', 'line', 'buf', 'message',
def __init__(self, path: str):
self.path = path
self.fh = open(path, 'r', newline='')
self.line = 0
self.buf = MBoxReaderBuffer()
self.message = None
def get_message(self):
while True:
line = self.fh.readline()
#
# We have reached the final message in the stream.
#
if line is None or line == '':
if self.message:
ret = self.message
ret.finish()
self.message = None
return ret
return None
line = line.replace('\x00', '')
self.line += 1
#
# Load the line in the circular mbox state buffer.
#
self.buf.add(line)
ret = None
#
# If we are at the start of a new message...
#
if self.buf.is_start():
if self.message is not None:
#
# If we already have a message, return it.
#
ret = self.message
#
# ...Prepare a new message object.
#
self.message = Message()
elif not self.buf.is_end():
if self.message is not None:
#
# Buffer the line into the current message.
#
self.message.readline(line)
#
# Return the message if we have one.
#
if ret:
ret.finish()
return ret
def messages(self):
while True:
message = self.get_message()
if message is None:
break
yield message