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# (C) 2005 Canonical Ltd
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
# 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
import stat, os, sha, time
from binascii import b2a_qp, a2b_qp
from trace import mutter
# file fingerprints are: (path, size, mtime, ctime, ino, dev).
#
# if this is the same for this file as in the previous revision, we
# assume the content is the same and the SHA-1 is the same.
# This is stored in a fingerprint file that also contains the file-id
# and the content SHA-1.
# Thus for any given file we can quickly get the SHA-1, either from
# the cache or if the cache is out of date.
# At the moment this is stored in a simple textfile; it might be nice
# to use a tdb instead.
# What we need:
# build a new cache from scratch
# load cache, incrementally update it
# TODO: Have a paranoid mode where we always compare the texts and
# always recalculate the digest, to trap modification without stat
# change and SHA collisions.
def fingerprint(path, abspath):
try:
fs = os.lstat(abspath)
except OSError:
# might be missing, etc
return None
if stat.S_ISDIR(fs.st_mode):
return None
return (fs.st_size, fs.st_mtime,
fs.st_ctime, fs.st_ino, fs.st_dev)
def write_cache(branch, entry_iter):
outf = branch.controlfile('work-cache.tmp', 'wt')
for entry in entry_iter:
outf.write(entry[0] + ' ' + entry[1] + ' ')
outf.write(b2a_qp(entry[2], True))
outf.write(' %d %d %d %d %d\n' % entry[3:])
outf.close()
os.rename(branch.controlfilename('work-cache.tmp'),
branch.controlfilename('work-cache'))
def load_cache(branch):
cache = {}
try:
cachefile = branch.controlfile('work-cache', 'rt')
except IOError:
return cache
for l in cachefile:
f = l.split(' ')
file_id = f[0]
if file_id in cache:
raise BzrError("duplicated file_id in cache: {%s}" % file_id)
cache[file_id] = (f[0], f[1], a2b_qp(f[2])) + tuple([long(x) for x in f[3:]])
return cache
def _files_from_inventory(inv):
for path, ie in inv.iter_entries():
if ie.kind != 'file':
continue
yield ie.file_id, path
def build_cache(branch):
inv = branch.read_working_inventory()
cache = {}
_update_cache_from_list(branch, cache, _files_from_inventory(inv))
def update_cache(branch, inv):
# TODO: It's supposed to be faster to stat the files in order by inum.
# We don't directly know the inum of the files of course but we do
# know where they were last sighted, so we can sort by that.
cache = load_cache(branch)
return _update_cache_from_list(branch, cache, _files_from_inventory(inv))
def _update_cache_from_list(branch, cache, to_update):
"""Update the cache to have info on the named files.
to_update is a sequence of (file_id, path) pairs.
"""
hardcheck = dirty = 0
for file_id, path in to_update:
fap = branch.abspath(path)
fp = fingerprint(fap, path)
cacheentry = cache.get(file_id)
if fp == None: # not here
if cacheentry:
del cache[file_id]
dirty += 1
continue
if cacheentry and (cacheentry[3:] == fp):
continue # all stat fields unchanged
hardcheck += 1
dig = sha.new(file(fap, 'rb').read()).hexdigest()
if cacheentry == None or dig != cacheentry[1]:
# if there was no previous entry for this file, or if the
# SHA has changed, then update the cache
cacheentry = (file_id, dig, path) + fp
cache[file_id] = cacheentry
dirty += 1
mutter('work cache: read %d files, %d changed' % (hardcheck, dirty))
if dirty:
write_cache(branch, cache.itervalues())
return cache
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