Squashed 'yocto-poky/' content from commit ea562de
git-subtree-dir: yocto-poky
git-subtree-split: ea562de57590c966cd5a75fda8defecd397e6436
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 @@
+# Local file checksum cache implementation
+#
+# Copyright (C) 2012 Intel Corporation
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License version 2 as
+# published by the Free Software Foundation.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+import os
+import stat
+import bb.utils
+import logging
+from bb.cache import MultiProcessCache
+
+logger = logging.getLogger("BitBake.Cache")
+
+try:
+ import cPickle as pickle
+except ImportError:
+ import pickle
+ logger.info("Importing cPickle failed. "
+ "Falling back to a very slow implementation.")
+
+
+# mtime cache (non-persistent)
+# based upon the assumption that files do not change during bitbake run
+class FileMtimeCache(object):
+ cache = {}
+
+ def cached_mtime(self, f):
+ if f not in self.cache:
+ self.cache[f] = os.stat(f)[stat.ST_MTIME]
+ return self.cache[f]
+
+ def cached_mtime_noerror(self, f):
+ if f not in self.cache:
+ try:
+ self.cache[f] = os.stat(f)[stat.ST_MTIME]
+ except OSError:
+ return 0
+ return self.cache[f]
+
+ def update_mtime(self, f):
+ self.cache[f] = os.stat(f)[stat.ST_MTIME]
+ return self.cache[f]
+
+ def clear(self):
+ self.cache.clear()
+
+# Checksum + mtime cache (persistent)
+class FileChecksumCache(MultiProcessCache):
+ cache_file_name = "local_file_checksum_cache.dat"
+ CACHE_VERSION = 1
+
+ def __init__(self):
+ self.mtime_cache = FileMtimeCache()
+ MultiProcessCache.__init__(self)
+
+ def get_checksum(self, f):
+ entry = self.cachedata[0].get(f)
+ cmtime = self.mtime_cache.cached_mtime(f)
+ if entry:
+ (mtime, hashval) = entry
+ if cmtime == mtime:
+ return hashval
+ else:
+ bb.debug(2, "file %s changed mtime, recompute checksum" % f)
+
+ hashval = bb.utils.md5_file(f)
+ self.cachedata_extras[0][f] = (cmtime, hashval)
+ return hashval
+
+ def merge_data(self, source, dest):
+ for h in source[0]:
+ if h in dest:
+ (smtime, _) = source[0][h]
+ (dmtime, _) = dest[0][h]
+ if smtime > dmtime:
+ dest[0][h] = source[0][h]
+ else:
+ dest[0][h] = source[0][h]