# Copyright (C) 2010, 2011 Sebastian Thiel (byronimo@gmail.com) and contributors
#
# This module is part of GitDB and is released under
# the New BSD License: http://www.opensource.org/licenses/bsd-license.php
import codecs
from gitdb.db.base import (
CompoundDB,
)
__all__ = ('ReferenceDB', )
class ReferenceDB(CompoundDB):
"""A database consisting of database referred to in a file"""
# Configuration
# Specifies the object database to use for the paths found in the alternates
# file. If None, it defaults to the GitDB
ObjectDBCls = None
def __init__(self, ref_file):
super().__init__()
self._ref_file = ref_file
def _set_cache_(self, attr):
if attr == '_dbs':
self._dbs = list()
self._update_dbs_from_ref_file()
else:
super()._set_cache_(attr)
# END handle attrs
def _update_dbs_from_ref_file(self):
dbcls = self.ObjectDBCls
if dbcls is None:
# late import
from gitdb.db.git import GitDB
dbcls = GitDB
# END get db type
# try to get as many as possible, don't fail if some are unavailable
ref_paths = list()
try:
with codecs.open(self._ref_file, 'r', encoding="utf-8") as f:
ref_paths = [l.strip() for l in f]
except OSError:
pass
# END handle alternates
ref_paths_set = set(ref_paths)
cur_ref_paths_set = {db.root_path() for db in self._dbs}
# remove existing
for path in (cur_ref_paths_set - ref_paths_set):
for i, db in enumerate(self._dbs[:]):
if db.root_path() == path:
del(self._dbs[i])
continue
# END del matching db
# END for each path to remove
# add new
# sort them to maintain order
added_paths = sorted(ref_paths_set - cur_ref_paths_set, key=lambda p: ref_paths.index(p))
for path in added_paths:
try:
db = dbcls(path)
# force an update to verify path
if isinstance(db, CompoundDB):
db.databases()
# END verification
self._dbs.append(db)
except Exception:
# ignore invalid paths or issues
pass
# END for each path to add
def update_cache(self, force=False):
# re-read alternates and update databases
self._update_dbs_from_ref_file()
return super().update_cache(force)
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