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# Copyright 2002 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
"""Invoke rdiff utility to make signatures, deltas, or patch"""
import os, librsync
import Globals, log, static, TempFile, rpath
def get_signature(rp, blocksize = None):
"""Take signature of rpin file and return in file object"""
if not blocksize: blocksize = find_blocksize(rp.getsize())
log.Log("Getting signature of %s with blocksize %s" %
(rp.get_indexpath(), blocksize), 7)
return librsync.SigFile(rp.open("rb"), blocksize)
def find_blocksize(file_len):
"""Return a reasonable block size to use on files of length file_len
If the block size is too big, deltas will be bigger than is
necessary. If the block size is too small, making deltas and
patching can take a really long time.
"""
if file_len < 1024000: return 512 # set minimum of 512 bytes
else: # Split file into about 2000 pieces, rounding to 512
return long((file_len/(2000*512))*512)
def get_delta_sigfileobj(sig_fileobj, rp_new):
"""Like get_delta but signature is in a file object"""
log.Log("Getting delta of %s with signature stream" % (rp_new.path,), 7)
return librsync.DeltaFile(sig_fileobj, rp_new.open("rb"))
def get_delta_sigrp(rp_signature, rp_new):
"""Take signature rp and new rp, return delta file object"""
log.Log("Getting delta of %s with signature %s" %
(rp_new.path, rp_signature.get_indexpath()), 7)
return librsync.DeltaFile(rp_signature.open("rb"), rp_new.open("rb"))
def write_delta(basis, new, delta, compress = None):
"""Write rdiff delta which brings basis to new"""
log.Log("Writing delta %s from %s -> %s" %
(basis.path, new.path, delta.path), 7)
deltafile = librsync.DeltaFile(get_signature(basis), new.open("rb"))
delta.write_from_fileobj(deltafile, compress)
def write_patched_fp(basis_fp, delta_fp, out_fp):
"""Write patched file to out_fp given input fps. Closes input files"""
rpath.copyfileobj(librsync.PatchedFile(basis_fp, delta_fp), out_fp)
assert not basis_fp.close() and not delta_fp.close()
def write_via_tempfile(fp, rp):
"""Write fileobj fp to rp by writing to tempfile and renaming"""
tf = TempFile.new(rp)
tf.write_from_fileobj(fp)
rpath.rename(tf, rp)
def patch_local(rp_basis, rp_delta, outrp = None, delta_compressed = None):
"""Patch routine that must be run locally, writes to outrp
This should be run local to rp_basis because it needs to be a real
file (librsync may need to seek around in it). If outrp is None,
patch rp_basis instead.
"""
assert rp_basis.conn is Globals.local_connection
if delta_compressed: deltafile = rp_delta.open("rb", 1)
else: deltafile = rp_delta.open("rb")
patchfile = librsync.PatchedFile(rp_basis.open("rb"), deltafile)
if outrp: outrp.write_from_fileobj(patchfile)
else: write_via_tempfile(patchfile, rp_basis)
def copy_local(rpin, rpout, rpnew = None):
"""Write rpnew == rpin using rpout as basis. rpout and rpnew local"""
assert rpout.conn is Globals.local_connection
deltafile = rpin.conn.librsync.DeltaFile(get_signature(rpout),
rpin.open("rb"))
patched_file = librsync.PatchedFile(rpout.open("rb"), deltafile)
if rpnew: rpnew.write_from_fileobj(patched_file)
else: write_via_tempfile(patched_file, rpout)
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