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# Copyright 2005 Ben Escoto
#
# This file is part of rdiff-backup.
#
# rdiff-backup is free software; you can redistribute it and/or modify
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.
#
# rdiff-backup 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
# General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with rdiff-backup; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
# USA
"""Contains a file wrapper that returns a hash on close"""
import sha
import Globals
class FileWrapper:
"""Wrapper around a file-like object
Only use this with files that will be read through in a single
pass and then closed. (There is no seek().) When you close it,
return value will be a Report.
Currently this just calculates a sha1sum of the datastream.
"""
def __init__(self, fileobj):
self.fileobj = fileobj
self.sha1 = sha.new()
self.closed = 0
def read(self, length = -1):
assert not self.closed
buf = self.fileobj.read(length)
self.sha1.update(buf)
return buf
def close(self):
return Report(self.fileobj.close(), self.sha1.hexdigest())
class Report:
"""Hold final information about a byte stream"""
def __init__(self, close_val, sha1_digest):
assert not close_val # For now just assume inner file closes correctly
self.sha1_digest = sha1_digest
def compute_sha1(rp, compressed = 0):
"""Return the hex sha1 hash of given rpath"""
assert rp.conn is Globals.local_connection # inefficient not to do locally
digest = compute_sha1_fp(rp.open("r", compressed))
rp.set_sha1(digest)
return digest
def compute_sha1_fp(fp, compressed = 0):
"""Return hex sha1 hash of given file-like object"""
blocksize = Globals.blocksize
fw = FileWrapper(fp)
while 1:
if not fw.read(blocksize): break
return fw.close().sha1_digest
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