1 # Copyright 2011 GRNET S.A. All rights reserved.
3 # Redistribution and use in source and binary forms, with or
4 # without modification, are permitted provided that the following
7 # 1. Redistributions of source code must retain the above
8 # copyright notice, this list of conditions and the following
11 # 2. Redistributions in binary form must reproduce the above
12 # copyright notice, this list of conditions and the following
13 # disclaimer in the documentation and/or other materials
14 # provided with the distribution.
16 # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
17 # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
18 # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
19 # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
20 # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
23 # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
24 # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
26 # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 # POSSIBILITY OF SUCH DAMAGE.
29 # The views and conclusions contained in the software and
30 # documentation are those of the authors and should not be
31 # interpreted as representing official policies, either expressed
32 # or implied, of GRNET S.A.
34 from os import makedirs, unlink
35 from os.path import isdir, realpath, exists, join
36 from binascii import hexlify
38 from context_file import ContextFile
43 Required contstructor parameters: mappath, namelen.
49 def __init__(self, **params):
51 self.namelen = params['namelen']
52 mappath = realpath(params['mappath'])
53 if not isdir(mappath):
54 if not exists(mappath):
57 raise ValueError("Variable mappath '%s' is not a directory" % (mappath,))
58 self.mappath = mappath
60 def _get_rear_map(self, maphash, create=0):
61 filename = hexlify(maphash)
62 dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6])
65 name = join(dir, filename)
66 return ContextFile(name, create)
68 def _check_rear_map(self, maphash):
69 filename = hexlify(maphash)
70 dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6])
71 name = join(dir, filename)
74 def map_retr(self, maphash, blkoff=0, nr=100000000000000):
75 """Return as a list, part of the hashes map of an object
76 at the given block offset.
77 By default, return the whole hashes map.
79 namelen = self.namelen
82 with self._get_rear_map(maphash, 0) as rmap:
84 hashes = list(rmap.sync_read_chunks(namelen, nr, blkoff))
87 def map_stor(self, maphash, hashes=(), blkoff=0, create=1):
88 """Store hashes in the given hashes map."""
89 namelen = self.namelen
90 if self._check_rear_map(maphash):
92 with self._get_rear_map(maphash, 1) as rmap:
93 rmap.sync_write_chunks(namelen, blkoff, hashes, None)