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#
# Copyright (C) 2006 Robey Pointer <robey@lag.net>
#
# 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
#
"""
indexing of the comment text of revisions, for fast searching.
two separate 'shelve' files are created:
- recorded: revid -> 1 (if the revid is indexed)
- index: 3-letter substring -> list(revids)
"""
import logging
import os
import re
import shelve
import threading
import time
from loggerhead import util
from loggerhead.util import decorator
from loggerhead.lockfile import LockFile
# if any substring index reaches this many revids, replace the entry with
# an ALL marker -- it's not worth an explicit index.
ALL_THRESHOLD = 1000
ALL = 'ALL'
with_lock = util.with_lock('_lock')
def normalize_string(s):
"""
remove any punctuation and normalize all whitespace to a single space.
"""
s = util.to_utf8(s).lower()
# remove apostrophes completely.
s = re.sub(r"'", '', s)
# convert other garbage into space
s = re.sub(r'[^\w\d]', ' ', s)
# compress multiple spaces into one.
s = re.sub(r'\s{2,}', ' ', s)
# and finally remove leading/trailing whitespace
s = s.strip()
return s
class TextIndex (object):
def __init__(self, history, cache_path):
self.history = history
self.log = history.log
if not os.path.exists(cache_path):
os.mkdir(cache_path)
self._recorded_filename = os.path.join(cache_path, 'textindex-recorded')
self._index_filename = os.path.join(cache_path, 'textindex')
# use a lockfile since the cache folder could be shared across different processes.
self._lock = LockFile(os.path.join(cache_path, 'index-lock'))
self._closed = False
self.log.info('Using search index; %d entries.', len(self))
def _is_indexed(self, revid, recorded):
return recorded.get(util.to_utf8(revid), None) is not None
@with_lock
def is_indexed(self, revid):
recorded = shelve.open(self._recorded_filename, 'c', protocol=2)
try:
return self._is_indexed(revid, recorded)
finally:
recorded.close()
@with_lock
def __len__(self):
recorded = shelve.open(self._recorded_filename, 'c', protocol=2)
try:
return len(recorded)
finally:
recorded.close()
@with_lock
def close(self):
self._closed = True
@with_lock
def closed(self):
return self._closed
@with_lock
def flush(self):
pass
@with_lock
def full(self):
recorded = shelve.open(self._recorded_filename, 'c', protocol=2)
try:
return (len(recorded) >= len(self.history.get_revision_history())) and (util.to_utf8(self.history.last_revid) in recorded)
finally:
recorded.close()
def _index_change(self, change, recorded, index):
"""
currently, only indexes the 'comment' field.
"""
comment = normalize_string(change.comment)
if len(comment) < 3:
return
for i in xrange(len(comment) - 2):
sub = comment[i:i + 3]
revid_set = index.get(sub, None)
if revid_set is None:
revid_set = set()
elif revid_set == ALL:
# this entry got too big
continue
revid_set.add(change.revid)
if len(revid_set) > ALL_THRESHOLD:
revid_set = ALL
index[sub] = revid_set
recorded[util.to_utf8(change.revid)] = True
@with_lock
def index_changes(self, revid_list):
recorded = shelve.open(self._recorded_filename, 'c', protocol=2)
index = shelve.open(self._index_filename, 'c', protocol=2)
try:
revid_list = [r for r in revid_list if not self._is_indexed(r, recorded)]
change_list = self.history.get_changes(revid_list)
for change in change_list:
self._index_change(change, recorded, index)
finally:
index.close()
recorded.close()
@with_lock
def find(self, text, revid_list=None):
index = shelve.open(self._index_filename, 'c', protocol=2)
try:
text = normalize_string(text)
if len(text) < 3:
return []
total_set = None
if revid_list is not None:
total_set = set(revid_list)
seen_all = False
for i in xrange(len(text) - 2):
sub = text[i:i + 3]
revid_set = index.get(sub, None)
if revid_set is None:
# zero matches, stop here.
return []
if revid_set == ALL:
# skip
seen_all = True
continue
if total_set is None:
total_set = revid_set
else:
total_set.intersection_update(revid_set)
if len(total_set) == 0:
return []
finally:
index.close()
# tricky: if seen_all is True, one of the substring indices was ALL
# (in other words, unindexed), so our results are actually a superset
# of the exact answer.
#
# if we cared, we could do a direct match on the result set and cull
# out any that aren't actually matches. for now, i'm gonna say that
# we DON'T care, and if one of the substrings hit ALL, there's a small
# chance that we'll give a few false positives.
return total_set
def check_rebuild(self, max_time=3600):
"""
check if there are any un-indexed revisions, and if so, index them.
but don't spend longer than C{max_time} on it.
"""
if self.closed() or self.full():
# all done
return
self.log.info('Building search index...')
work = list(self.history.get_revision_history())
start_time = time.time()
last_update = time.time()
count = 0
jump = 100
for i in xrange(0, len(work), jump):
r = work[i:i + jump]
self.index_changes(r)
if self.closed():
return
count += jump
now = time.time()
if now - start_time > 3600:
# there's no point working for hours. eventually we might even
# hit the next re-index interval, which would suck mightily.
self.log.info('Search indexing has worked for an hour; giving up for now.')
return
if now - last_update > 60:
self.log.info('Search indexing continues: %d/%d' % (min(count, len(work)), len(work)))
last_update = time.time()
# give someone else a chance at the lock
time.sleep(1)
self.log.info('Search index completed.')
self.flush()
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