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# $Id$
#
# Copyright (C) 2009--2012 Internet Systems Consortium ("ISC")
#
# Permission to use, copy, modify, and distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#
# THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
# REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
# AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
# INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
# LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
# OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
# PERFORMANCE OF THIS SOFTWARE.
"""
CSV utilities, moved here from myrpki.py.
"""
import csv
import os
class BadCSVSyntax(Exception):
"""
Bad CSV syntax.
"""
class csv_reader(object):
"""
Reader for tab-delimited text that's (slightly) friendlier than the
stock Python csv module (which isn't intended for direct use by
humans anyway, and neither was this package originally, but that
seems to be the way that it has evolved...).
Columns parameter specifies how many columns users of the reader
expect to see; lines with fewer columns will be padded with None
values.
Original API design for this class courtesy of Warren Kumari, but
don't blame him if you don't like what I did with his ideas.
"""
def __init__(self, filename, columns = None, min_columns = None, comment_characters = "#;"):
assert columns is None or isinstance(columns, int)
assert min_columns is None or isinstance(min_columns, int)
if columns is not None and min_columns is None:
min_columns = columns
self.filename = filename
self.columns = columns
self.min_columns = min_columns
self.comment_characters = comment_characters
self.file = open(filename, "r")
def __iter__(self):
line_number = 0
for line in self.file:
line_number += 1
line = line.strip()
if not line or line[0] in self.comment_characters:
continue
fields = line.split()
if self.min_columns is not None and len(fields) < self.min_columns:
raise BadCSVSyntax("%s:%d: Not enough columns in line %r" % (self.filename, line_number, line))
if self.columns is not None and len(fields) > self.columns:
raise BadCSVSyntax("%s:%d: Too many columns in line %r" % (self.filename, line_number, line))
if self.columns is not None and len(fields) < self.columns:
fields += tuple(None for i in xrange(self.columns - len(fields)))
yield fields
def __enter__(self):
return self
def __exit__(self, _type, value, traceback):
self.file.close()
class csv_writer(object):
"""
Writer object for tab delimited text. We just use the stock CSV
module in excel-tab mode for this.
If "renmwo" is set (default), the file will be written to
a temporary name and renamed to the real filename after closing.
"""
def __init__(self, filename, renmwo = True):
self.filename = filename
self.renmwo = "%s.~renmwo%d~" % (filename, os.getpid()) if renmwo else filename
self.file = open(self.renmwo, "w")
self.writer = csv.writer(self.file, dialect = csv.get_dialect("excel-tab"))
def __enter__(self):
return self
def __exit__(self, _type, value, traceback):
self.close()
def close(self):
"""
Close this writer.
"""
if self.file is not None:
self.file.close()
self.file = None
if self.filename != self.renmwo:
os.rename(self.renmwo, self.filename)
def __getattr__(self, attr):
"""
Fake inheritance from whatever object csv.writer deigns to give us.
"""
return getattr(self.writer, attr)
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