root / snf-pithos-backend / pithos / backends / lib / hashfiler / blocker.py @ c30635bf
History | View | Annotate | Download (4.6 kB)
1 |
# Copyright 2011-2012 GRNET S.A. All rights reserved.
|
---|---|
2 |
#
|
3 |
# Redistribution and use in source and binary forms, with or
|
4 |
# without modification, are permitted provided that the following
|
5 |
# conditions are met:
|
6 |
#
|
7 |
# 1. Redistributions of source code must retain the above
|
8 |
# copyright notice, this list of conditions and the following
|
9 |
# disclaimer.
|
10 |
#
|
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.
|
15 |
#
|
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.
|
28 |
#
|
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.
|
33 |
|
34 |
from hashlib import new as newhasher |
35 |
from binascii import hexlify |
36 |
|
37 |
from radosblocker import RadosBlocker |
38 |
from fileblocker import FileBlocker |
39 |
|
40 |
def intersect(a, b): |
41 |
""" return the intersection of two lists """
|
42 |
return list(set(a) & set(b)) |
43 |
|
44 |
def union(a, b): |
45 |
""" return the union of two lists """
|
46 |
return list(set(a) | set(b)) |
47 |
|
48 |
|
49 |
class Blocker(object): |
50 |
"""Blocker.
|
51 |
Required constructor parameters: blocksize, blockpath, hashtype,
|
52 |
blockpool.
|
53 |
"""
|
54 |
|
55 |
def __init__(self, **params): |
56 |
params['blockpool'] = 'blocks' |
57 |
self.rblocker = RadosBlocker(**params)
|
58 |
self.fblocker = FileBlocker(**params)
|
59 |
self.hashlen = self.rblocker.hashlen |
60 |
|
61 |
# def _get_rear_block(self, blkhash, create=0):
|
62 |
# return self.rblocker._get_rear_block(blkhash, create)
|
63 |
|
64 |
# def _check_rear_block(self, blkhash):
|
65 |
# return self.rblocker._check_rear_block(blkhash)
|
66 |
# return self.rblocker._check_rear_block(blkhash) and
|
67 |
# self.fblocker._check_rear_block(blkhash)
|
68 |
|
69 |
def block_hash(self, data): |
70 |
"""Hash a block of data"""
|
71 |
return self.rblocker.block_hash(data) |
72 |
|
73 |
def block_ping(self, hashes): |
74 |
"""Check hashes for existence and
|
75 |
return those missing from block storage.
|
76 |
"""
|
77 |
# return self.rblocker.block_ping(hashes)
|
78 |
r = self.rblocker.block_ping(hashes)
|
79 |
f = self.fblocker.block_ping(hashes)
|
80 |
return union(r, f)
|
81 |
|
82 |
def block_retr(self, hashes): |
83 |
"""Retrieve blocks from storage by their hashes."""
|
84 |
return self.fblocker.block_retr(hashes) |
85 |
|
86 |
def block_stor(self, blocklist): |
87 |
"""Store a bunch of blocks and return (hashes, missing).
|
88 |
Hashes is a list of the hashes of the blocks,
|
89 |
missing is a list of indices in that list indicating
|
90 |
which blocks were missing from the store.
|
91 |
"""
|
92 |
# return self.rblocker.block_stor(blocklist)
|
93 |
(hashes, r_missing) = self.rblocker.block_stor(blocklist)
|
94 |
(_, f_missing) = self.fblocker.block_stor(blocklist)
|
95 |
return (hashes, union(r_missing, f_missing))
|
96 |
|
97 |
|
98 |
def block_delta(self, blkhash, offset, data): |
99 |
"""Construct and store a new block from a given block
|
100 |
and a data 'patch' applied at offset. Return:
|
101 |
(the hash of the new block, if the block already existed)
|
102 |
"""
|
103 |
# return self.rblocker.block_delta(blkhash, offset, data)
|
104 |
|
105 |
(f_hash, f_existed) = self.fblocker.block_delta(blkhash, offset, data)
|
106 |
(r_hash, r_existed) = self.rblocker.block_delta(blkhash, offset, data)
|
107 |
if not r_hash and not f_hash: |
108 |
return None, None |
109 |
if not r_hash: |
110 |
block = self.fblocker.block_retr((blkhash,))
|
111 |
if not block: |
112 |
return None, None |
113 |
block = block[0]
|
114 |
newblock = block[:offset] + data |
115 |
if len(newblock) > blocksize: |
116 |
newblock = newblock[:blocksize] |
117 |
elif len(newblock) < blocksize: |
118 |
newblock += block[len(newblock):]
|
119 |
r_hash, r_existed = self.rblocker.block_stor((newblock,))
|
120 |
|
121 |
return f_hash, 1 if r_existed and f_existed else 0 |