summaryrefslogtreecommitdiffstats
path: root/bitbake/lib/bb/checksum.py
diff options
context:
space:
mode:
Diffstat (limited to 'bitbake/lib/bb/checksum.py')
-rw-r--r--bitbake/lib/bb/checksum.py90
1 files changed, 90 insertions, 0 deletions
diff --git a/bitbake/lib/bb/checksum.py b/bitbake/lib/bb/checksum.py
new file mode 100644
index 0000000..514ff0b
--- /dev/null
+++ b/bitbake/lib/bb/checksum.py
@@ -0,0 +1,90 @@
1# Local file checksum cache implementation
2#
3# Copyright (C) 2012 Intel Corporation
4#
5# This program is free software; you can redistribute it and/or modify
6# it under the terms of the GNU General Public License version 2 as
7# published by the Free Software Foundation.
8#
9# This program is distributed in the hope that it will be useful,
10# but WITHOUT ANY WARRANTY; without even the implied warranty of
11# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12# GNU General Public License for more details.
13#
14# You should have received a copy of the GNU General Public License along
15# with this program; if not, write to the Free Software Foundation, Inc.,
16# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
17
18import os
19import stat
20import bb.utils
21import logging
22from bb.cache import MultiProcessCache
23
24logger = logging.getLogger("BitBake.Cache")
25
26try:
27 import cPickle as pickle
28except ImportError:
29 import pickle
30 logger.info("Importing cPickle failed. "
31 "Falling back to a very slow implementation.")
32
33
34# mtime cache (non-persistent)
35# based upon the assumption that files do not change during bitbake run
36class FileMtimeCache(object):
37 cache = {}
38
39 def cached_mtime(self, f):
40 if f not in self.cache:
41 self.cache[f] = os.stat(f)[stat.ST_MTIME]
42 return self.cache[f]
43
44 def cached_mtime_noerror(self, f):
45 if f not in self.cache:
46 try:
47 self.cache[f] = os.stat(f)[stat.ST_MTIME]
48 except OSError:
49 return 0
50 return self.cache[f]
51
52 def update_mtime(self, f):
53 self.cache[f] = os.stat(f)[stat.ST_MTIME]
54 return self.cache[f]
55
56 def clear(self):
57 self.cache.clear()
58
59# Checksum + mtime cache (persistent)
60class FileChecksumCache(MultiProcessCache):
61 cache_file_name = "local_file_checksum_cache.dat"
62 CACHE_VERSION = 1
63
64 def __init__(self):
65 self.mtime_cache = FileMtimeCache()
66 MultiProcessCache.__init__(self)
67
68 def get_checksum(self, f):
69 entry = self.cachedata[0].get(f)
70 cmtime = self.mtime_cache.cached_mtime(f)
71 if entry:
72 (mtime, hashval) = entry
73 if cmtime == mtime:
74 return hashval
75 else:
76 bb.debug(2, "file %s changed mtime, recompute checksum" % f)
77
78 hashval = bb.utils.md5_file(f)
79 self.cachedata_extras[0][f] = (cmtime, hashval)
80 return hashval
81
82 def merge_data(self, source, dest):
83 for h in source[0]:
84 if h in dest:
85 (smtime, _) = source[0][h]
86 (dmtime, _) = dest[0][h]
87 if smtime > dmtime:
88 dest[0][h] = source[0][h]
89 else:
90 dest[0][h] = source[0][h]