root / snf-pithos-backend / pithos / backends / lib / hashfiler / mapper.py @ 2715ade4
History | View | Annotate | Download (3.5 kB)
1 | 2e662088 | Antony Chazapis | # Copyright 2011-2012 GRNET S.A. All rights reserved.
|
---|---|---|---|
2 | 2715ade4 | Sofia Papagiannaki | #
|
3 | a9b3f29d | Antony Chazapis | # Redistribution and use in source and binary forms, with or
|
4 | a9b3f29d | Antony Chazapis | # without modification, are permitted provided that the following
|
5 | a9b3f29d | Antony Chazapis | # conditions are met:
|
6 | 2715ade4 | Sofia Papagiannaki | #
|
7 | a9b3f29d | Antony Chazapis | # 1. Redistributions of source code must retain the above
|
8 | a9b3f29d | Antony Chazapis | # copyright notice, this list of conditions and the following
|
9 | a9b3f29d | Antony Chazapis | # disclaimer.
|
10 | 2715ade4 | Sofia Papagiannaki | #
|
11 | a9b3f29d | Antony Chazapis | # 2. Redistributions in binary form must reproduce the above
|
12 | a9b3f29d | Antony Chazapis | # copyright notice, this list of conditions and the following
|
13 | a9b3f29d | Antony Chazapis | # disclaimer in the documentation and/or other materials
|
14 | a9b3f29d | Antony Chazapis | # provided with the distribution.
|
15 | 2715ade4 | Sofia Papagiannaki | #
|
16 | a9b3f29d | Antony Chazapis | # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
|
17 | a9b3f29d | Antony Chazapis | # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
18 | a9b3f29d | Antony Chazapis | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
19 | a9b3f29d | Antony Chazapis | # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
|
20 | a9b3f29d | Antony Chazapis | # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
21 | a9b3f29d | Antony Chazapis | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
22 | a9b3f29d | Antony Chazapis | # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
23 | a9b3f29d | Antony Chazapis | # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
24 | a9b3f29d | Antony Chazapis | # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
25 | a9b3f29d | Antony Chazapis | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
26 | a9b3f29d | Antony Chazapis | # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
27 | a9b3f29d | Antony Chazapis | # POSSIBILITY OF SUCH DAMAGE.
|
28 | 2715ade4 | Sofia Papagiannaki | #
|
29 | a9b3f29d | Antony Chazapis | # The views and conclusions contained in the software and
|
30 | a9b3f29d | Antony Chazapis | # documentation are those of the authors and should not be
|
31 | a9b3f29d | Antony Chazapis | # interpreted as representing official policies, either expressed
|
32 | a9b3f29d | Antony Chazapis | # or implied, of GRNET S.A.
|
33 | a9b3f29d | Antony Chazapis | |
34 | a9b3f29d | Antony Chazapis | from os import makedirs, unlink |
35 | 1c2fc0ff | Antony Chazapis | from os.path import isdir, realpath, exists, join |
36 | 1c2fc0ff | Antony Chazapis | from binascii import hexlify |
37 | a9b3f29d | Antony Chazapis | |
38 | 6f4bce7b | Antony Chazapis | from context_file import ContextFile |
39 | a9b3f29d | Antony Chazapis | |
40 | a9b3f29d | Antony Chazapis | |
41 | a9b3f29d | Antony Chazapis | class Mapper(object): |
42 | a9b3f29d | Antony Chazapis | """Mapper.
|
43 | 94f33595 | Antony Chazapis | Required constructor parameters: mappath, namelen.
|
44 | a9b3f29d | Antony Chazapis | """
|
45 | 2715ade4 | Sofia Papagiannaki | |
46 | a9b3f29d | Antony Chazapis | mappath = None
|
47 | a9b3f29d | Antony Chazapis | namelen = None
|
48 | a9b3f29d | Antony Chazapis | |
49 | a9b3f29d | Antony Chazapis | def __init__(self, **params): |
50 | a9b3f29d | Antony Chazapis | self.params = params
|
51 | a9b3f29d | Antony Chazapis | self.namelen = params['namelen'] |
52 | a9b3f29d | Antony Chazapis | mappath = realpath(params['mappath'])
|
53 | a9b3f29d | Antony Chazapis | if not isdir(mappath): |
54 | a9b3f29d | Antony Chazapis | if not exists(mappath): |
55 | a9b3f29d | Antony Chazapis | makedirs(mappath) |
56 | a9b3f29d | Antony Chazapis | else:
|
57 | 2715ade4 | Sofia Papagiannaki | raise ValueError( |
58 | 2715ade4 | Sofia Papagiannaki | "Variable mappath '%s' is not a directory" % (mappath,))
|
59 | a9b3f29d | Antony Chazapis | self.mappath = mappath
|
60 | a9b3f29d | Antony Chazapis | |
61 | 1c2fc0ff | Antony Chazapis | def _get_rear_map(self, maphash, create=0): |
62 | 1c2fc0ff | Antony Chazapis | filename = hexlify(maphash) |
63 | 1c2fc0ff | Antony Chazapis | dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6]) |
64 | 1c2fc0ff | Antony Chazapis | if not exists(dir): |
65 | 1c2fc0ff | Antony Chazapis | makedirs(dir)
|
66 | 1c2fc0ff | Antony Chazapis | name = join(dir, filename)
|
67 | a9b3f29d | Antony Chazapis | return ContextFile(name, create)
|
68 | a9b3f29d | Antony Chazapis | |
69 | 1c2fc0ff | Antony Chazapis | def _check_rear_map(self, maphash): |
70 | 1c2fc0ff | Antony Chazapis | filename = hexlify(maphash) |
71 | 1c2fc0ff | Antony Chazapis | dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6]) |
72 | 1c2fc0ff | Antony Chazapis | name = join(dir, filename)
|
73 | 1c2fc0ff | Antony Chazapis | return exists(name)
|
74 | a9b3f29d | Antony Chazapis | |
75 | 1c2fc0ff | Antony Chazapis | def map_retr(self, maphash, blkoff=0, nr=100000000000000): |
76 | a9b3f29d | Antony Chazapis | """Return as a list, part of the hashes map of an object
|
77 | a9b3f29d | Antony Chazapis | at the given block offset.
|
78 | a9b3f29d | Antony Chazapis | By default, return the whole hashes map.
|
79 | a9b3f29d | Antony Chazapis | """
|
80 | a9b3f29d | Antony Chazapis | namelen = self.namelen
|
81 | a9b3f29d | Antony Chazapis | hashes = () |
82 | a9b3f29d | Antony Chazapis | |
83 | 1c2fc0ff | Antony Chazapis | with self._get_rear_map(maphash, 0) as rmap: |
84 | a9b3f29d | Antony Chazapis | if rmap:
|
85 | a9b3f29d | Antony Chazapis | hashes = list(rmap.sync_read_chunks(namelen, nr, blkoff))
|
86 | a9b3f29d | Antony Chazapis | return hashes
|
87 | a9b3f29d | Antony Chazapis | |
88 | 1c2fc0ff | Antony Chazapis | def map_stor(self, maphash, hashes=(), blkoff=0, create=1): |
89 | 1c2fc0ff | Antony Chazapis | """Store hashes in the given hashes map."""
|
90 | a9b3f29d | Antony Chazapis | namelen = self.namelen
|
91 | 1c2fc0ff | Antony Chazapis | if self._check_rear_map(maphash): |
92 | 1c2fc0ff | Antony Chazapis | return
|
93 | 1c2fc0ff | Antony Chazapis | with self._get_rear_map(maphash, 1) as rmap: |
94 | a9b3f29d | Antony Chazapis | rmap.sync_write_chunks(namelen, blkoff, hashes, None) |