root / snf-pithos-backend / pithos / backends / lib / hashfiler / filemapper.py @ c30635bf
History | View | Annotate | Download (3.5 kB)
1 | c30635bf | Filippos Giannakos | # Copyright 2011-2012 GRNET S.A. All rights reserved.
|
---|---|---|---|
2 | c30635bf | Filippos Giannakos | #
|
3 | c30635bf | Filippos Giannakos | # Redistribution and use in source and binary forms, with or
|
4 | c30635bf | Filippos Giannakos | # without modification, are permitted provided that the following
|
5 | c30635bf | Filippos Giannakos | # conditions are met:
|
6 | c30635bf | Filippos Giannakos | #
|
7 | c30635bf | Filippos Giannakos | # 1. Redistributions of source code must retain the above
|
8 | c30635bf | Filippos Giannakos | # copyright notice, this list of conditions and the following
|
9 | c30635bf | Filippos Giannakos | # disclaimer.
|
10 | c30635bf | Filippos Giannakos | #
|
11 | c30635bf | Filippos Giannakos | # 2. Redistributions in binary form must reproduce the above
|
12 | c30635bf | Filippos Giannakos | # copyright notice, this list of conditions and the following
|
13 | c30635bf | Filippos Giannakos | # disclaimer in the documentation and/or other materials
|
14 | c30635bf | Filippos Giannakos | # provided with the distribution.
|
15 | c30635bf | Filippos Giannakos | #
|
16 | c30635bf | Filippos Giannakos | # THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
|
17 | c30635bf | Filippos Giannakos | # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
|
18 | c30635bf | Filippos Giannakos | # WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
19 | c30635bf | Filippos Giannakos | # PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
|
20 | c30635bf | Filippos Giannakos | # CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
21 | c30635bf | Filippos Giannakos | # SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
|
22 | c30635bf | Filippos Giannakos | # LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
|
23 | c30635bf | Filippos Giannakos | # USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
24 | c30635bf | Filippos Giannakos | # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
25 | c30635bf | Filippos Giannakos | # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
26 | c30635bf | Filippos Giannakos | # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
27 | c30635bf | Filippos Giannakos | # POSSIBILITY OF SUCH DAMAGE.
|
28 | c30635bf | Filippos Giannakos | #
|
29 | c30635bf | Filippos Giannakos | # The views and conclusions contained in the software and
|
30 | c30635bf | Filippos Giannakos | # documentation are those of the authors and should not be
|
31 | c30635bf | Filippos Giannakos | # interpreted as representing official policies, either expressed
|
32 | c30635bf | Filippos Giannakos | # or implied, of GRNET S.A.
|
33 | c30635bf | Filippos Giannakos | |
34 | c30635bf | Filippos Giannakos | from os import makedirs, unlink |
35 | c30635bf | Filippos Giannakos | from os.path import isdir, realpath, exists, join |
36 | c30635bf | Filippos Giannakos | from binascii import hexlify |
37 | c30635bf | Filippos Giannakos | |
38 | c30635bf | Filippos Giannakos | from context_file import ContextFile |
39 | c30635bf | Filippos Giannakos | |
40 | c30635bf | Filippos Giannakos | |
41 | c30635bf | Filippos Giannakos | class FileMapper(object): |
42 | c30635bf | Filippos Giannakos | """Mapper.
|
43 | c30635bf | Filippos Giannakos | Required constructor parameters: mappath, namelen.
|
44 | c30635bf | Filippos Giannakos | """
|
45 | c30635bf | Filippos Giannakos | |
46 | c30635bf | Filippos Giannakos | mappath = None
|
47 | c30635bf | Filippos Giannakos | namelen = None
|
48 | c30635bf | Filippos Giannakos | |
49 | c30635bf | Filippos Giannakos | def __init__(self, **params): |
50 | c30635bf | Filippos Giannakos | self.params = params
|
51 | c30635bf | Filippos Giannakos | self.namelen = params['namelen'] |
52 | c30635bf | Filippos Giannakos | mappath = realpath(params['mappath'])
|
53 | c30635bf | Filippos Giannakos | if not isdir(mappath): |
54 | c30635bf | Filippos Giannakos | if not exists(mappath): |
55 | c30635bf | Filippos Giannakos | makedirs(mappath) |
56 | c30635bf | Filippos Giannakos | else:
|
57 | c30635bf | Filippos Giannakos | raise ValueError("Variable mappath '%s' is not a directory" % (mappath,)) |
58 | c30635bf | Filippos Giannakos | self.mappath = mappath
|
59 | c30635bf | Filippos Giannakos | |
60 | c30635bf | Filippos Giannakos | def _get_rear_map(self, maphash, create=0): |
61 | c30635bf | Filippos Giannakos | filename = hexlify(maphash) |
62 | c30635bf | Filippos Giannakos | dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6]) |
63 | c30635bf | Filippos Giannakos | if not exists(dir): |
64 | c30635bf | Filippos Giannakos | makedirs(dir)
|
65 | c30635bf | Filippos Giannakos | name = join(dir, filename)
|
66 | c30635bf | Filippos Giannakos | return ContextFile(name, create)
|
67 | c30635bf | Filippos Giannakos | |
68 | c30635bf | Filippos Giannakos | def _check_rear_map(self, maphash): |
69 | c30635bf | Filippos Giannakos | filename = hexlify(maphash) |
70 | c30635bf | Filippos Giannakos | dir = join(self.mappath, filename[0:2], filename[2:4], filename[4:6]) |
71 | c30635bf | Filippos Giannakos | name = join(dir, filename)
|
72 | c30635bf | Filippos Giannakos | return exists(name)
|
73 | c30635bf | Filippos Giannakos | |
74 | c30635bf | Filippos Giannakos | def map_retr(self, maphash, blkoff=0, nr=100000000000000): |
75 | c30635bf | Filippos Giannakos | """Return as a list, part of the hashes map of an object
|
76 | c30635bf | Filippos Giannakos | at the given block offset.
|
77 | c30635bf | Filippos Giannakos | By default, return the whole hashes map.
|
78 | c30635bf | Filippos Giannakos | """
|
79 | c30635bf | Filippos Giannakos | namelen = self.namelen
|
80 | c30635bf | Filippos Giannakos | hashes = () |
81 | c30635bf | Filippos Giannakos | |
82 | c30635bf | Filippos Giannakos | with self._get_rear_map(maphash, 0) as rmap: |
83 | c30635bf | Filippos Giannakos | if rmap:
|
84 | c30635bf | Filippos Giannakos | hashes = list(rmap.sync_read_chunks(namelen, nr, blkoff))
|
85 | c30635bf | Filippos Giannakos | return hashes
|
86 | c30635bf | Filippos Giannakos | |
87 | c30635bf | Filippos Giannakos | def map_stor(self, maphash, hashes=(), blkoff=0, create=1): |
88 | c30635bf | Filippos Giannakos | """Store hashes in the given hashes map."""
|
89 | c30635bf | Filippos Giannakos | namelen = self.namelen
|
90 | c30635bf | Filippos Giannakos | if self._check_rear_map(maphash): |
91 | c30635bf | Filippos Giannakos | return
|
92 | c30635bf | Filippos Giannakos | with self._get_rear_map(maphash, 1) as rmap: |
93 | c30635bf | Filippos Giannakos | rmap.sync_write_chunks(namelen, blkoff, hashes, None)
|