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mirror of https://github.com/wting/autojump synced 2024-10-27 20:34:07 +00:00
wting_autojump/bin/autojump_data.py
Azat Khuzhin 97233e90c8 Use flock instead of temporary files to avoid races/purge on ENOSPC/fsync time
- races: two parallel `autojump --add` can lead to database purging
  (overwriting by one of tmp files)
- ENOSPC: will leave autojump.txt empty, because no free space available
- fsync: can take a while

All of this can be fixed with fsync(2).
2015-10-04 21:44:45 +03:00

133 lines
3.8 KiB
Python

#!/usr/bin/env python
# -*- coding: utf-8 -*-
from __future__ import print_function
from codecs import open
from collections import namedtuple
import os
import shutil
import sys
import fcntl
from time import time
if sys.version_info[0] == 3:
ifilter = filter
imap = map
else:
from itertools import ifilter
from itertools import imap
from autojump_utils import create_dir
from autojump_utils import unico
from autojump_utils import is_osx
from autojump_utils import is_python3
from autojump_utils import move_file
BACKUP_THRESHOLD = 24 * 60 * 60
Entry = namedtuple('Entry', ['path', 'weight'])
def dictify(entries):
"""
Converts a list of entries into a dictionary where
key = path
value = weight
"""
result = {}
for entry in entries:
result[entry.path] = entry.weight
return result
def entriefy(data):
"""Converts a dictionary into an iterator of entries."""
convert = lambda tup: Entry(*tup)
if is_python3():
return map(convert, data.items())
return imap(convert, data.iteritems())
def load(config):
"""Returns a dictonary (key=path, value=weight) loaded from data file."""
xdg_aj_home = os.path.join(
os.path.expanduser('~'),
'.local',
'share',
'autojump')
if is_osx() and os.path.exists(xdg_aj_home):
migrate_osx_xdg_data(config)
if not os.path.exists(config['data_path']):
return {}
# example: u'10.0\t/home/user\n' -> ['10.0', u'/home/user']
parse = lambda line: line.strip().split('\t')
correct_length = lambda x: len(x) == 2
# example: ['10.0', u'/home/user'] -> (u'/home/user', 10.0)
tupleize = lambda x: (x[1], float(x[0]))
try:
with open(
config['data_path'],
'r', encoding='utf-8',
errors='replace') as f:
fcntl.flock(f.fileno(), fcntl.LOCK_SH)
d = dict(
imap(
tupleize,
ifilter(correct_length, imap(parse, f))))
fcntl.flock(f.fileno(), fcntl.LOCK_UN)
return d
except (IOError, EOFError):
return load_backup(config)
def load_backup(config):
if os.path.exists(config['backup_path']):
move_file(config['backup_path'], config['data_path'])
return load(config)
return {}
def migrate_osx_xdg_data(config):
"""
Older versions incorrectly used Linux XDG_DATA_HOME paths on OS X. This
migrates autojump files from ~/.local/share/autojump to ~/Library/autojump
"""
assert is_osx(), "This function should only be run on OS X."
xdg_data_home = os.path.join(os.path.expanduser('~'), '.local', 'share')
xdg_aj_home = os.path.join(xdg_data_home, 'autojump')
data_path = os.path.join(xdg_aj_home, 'autojump.txt')
backup_path = os.path.join(xdg_aj_home, 'autojump.txt.bak')
if os.path.exists(data_path):
move_file(data_path, config['data_path'])
if os.path.exists(backup_path):
move_file(backup_path, config['backup_path'])
# cleanup
shutil.rmtree(xdg_aj_home)
if len(os.listdir(xdg_data_home)) == 0:
shutil.rmtree(xdg_data_home)
def save(config, data):
"""Save data and create backup, creating a new data file if necessary."""
create_dir(os.path.dirname(config['data_path']))
with open(config['data_path'], 'w', encoding='utf-8') as f:
fcntl.flock(f.fileno(), fcntl.LOCK_EX)
for path, weight in data.items():
f.write(unico("%s\t%s\n" % (weight, path)))
fcntl.flock(f.fileno(), fcntl.LOCK_UN)
# create backup file if it doesn't exist or is older than BACKUP_THRESHOLD
if not os.path.exists(config['backup_path']) or \
(time() - os.path.getmtime(config['backup_path']) > BACKUP_THRESHOLD): # noqa
shutil.copy(config['data_path'], config['backup_path'])