Simple script that mimicks rdiff, can help check rdiff-backup's librsync

git-svn-id: http://svn.savannah.nongnu.org/svn/rdiff-backup@493 2b77aa54-bcbc-44c9-a7ec-4f6cf2b41109

trunk/rdiff-backup/python-rdiff

+#!/usr/bin/env python
+
+import sys
+from rdiff_backup import librsync
+
+blocksize = 64*1024 # just used in copying
+librsync_blocksize = None # If not set, use defaults in _librsync module
+
+def usage():
+	"""Print usage and then exit"""
+	print """
+Usage: %(cmd)s "signature" basis_file signature_file
+       %(cmd)s "delta" signature_file new_file delta_file
+       %(cmd)s "patch" basis_file delta_file new_file
+""" % {'cmd': sys.argv[0]}
+	sys.exit(1)
+
+def copy_and_close(infp, outfp):
+	"""Copy file streams infp to outfp in blocks, closing when done"""
+	while 1:
+		buf = infp.read(blocksize)
+		if not buf: break
+		outfp.write(buf)
+	assert not infp.close() and not outfp.close()
+
+def write_sig(input_path, output_path):
+	"""Open file at input_path, write signature to output_path"""
+	infp = open(input_path, "rb")
+	if librsync_blocksize: sigfp = librsync.SigFile(infp, librsync_blocksize)
+	else: sigfp = librsync.SigFile(infp)
+	copy_and_close(sigfp, open(output_path, "wb"))
+
+def write_delta(sig_path, new_path, output_path):
+	"""Read signature and new file, write to delta to delta_path"""
+	deltafp = librsync.DeltaFile(open(sig_path, "rb"), open(new_path, "rb"))
+	copy_and_close(deltafp, open(output_path, "wb"))
+
+def write_patch(basis_path, delta_path, out_path):
+	"""Patch file at basis_path with delta at delta_path, write to out_path"""
+	patchfp = librsync.PatchedFile(open(basis_path, "rb"),
+								   open(delta_path, "rb"))
+	copy_and_close(patchfp, open(out_path, "wb"))
+
+def check_different(filelist):
+	"""Make sure no files the same"""
+	d = {}
+	for file in filelist: d[file] = file
+	assert len(d) == len(filelist), "Error, must use all different filenames"
+
+def Main():
+	"""Run program"""
+	if len(sys.argv) < 4: usage()
+	mode = sys.argv[1]
+	file_args = sys.argv[2:]
+	check_different(file_args)
+	if mode == "signature":
+		if len(file_args) != 2: usage()
+		write_sig(*file_args)
+	elif mode == "delta":
+		if len(file_args) != 3: usage()
+		write_delta(*file_args)
+	elif mode == "patch":
+		if len(file_args) != 3: usage()
+		write_patch(*file_args)
+	else: usage()
+
+
+if __name__ == "__main__": Main()
+