def load_from_location(self, location=None):
"""
Restores :class:`TrackDB` state from the pickled representation
stored at the specified location.
:param location: the location to load the data from
:type location: string
"""
if not location:
location = self.location
if not location:
raise AttributeError(
_("You did not specify a location to load the db from")
)
logger.debug("Loading %s DB from %s.", self.name, location)
pdata = common.open_shelf(location)
if "_dbversion" in pdata:
if int(pdata['_dbversion']) > int(self._dbversion):
raise common.VersionError("DB was created on a newer Exaile version.")
elif pdata['_dbversion'] < self._dbversion:
logger.info("Upgrading DB format....")
import shutil
shutil.copyfile(location, location + "-%s.bak" % pdata['_dbversion'])
import xl.migrations.database as dbmig
dbmig.handle_migration(
self, pdata, pdata['_dbversion'], self._dbversion
)
for attr in self.pickle_attrs:
try:
if 'tracks' == attr:
data = {}
for k in (x for x in pdata.keys() if x.startswith("tracks-")):
p = pdata[k]
tr = Track(_unpickles=p[0])
loc = tr.get_loc_for_io()
if loc not in data:
data[loc] = TrackHolder(tr, p[1], **p[2])
else:
logger.warning("Duplicate track found: %s", loc)
# presumably the second track was written because of an error,
# so use the first track found.
del pdata[k]
setattr(self, attr, data)
else:
setattr(self, attr, pdata.get(attr, getattr(self, attr)))
except Exception:
# FIXME: Do something about this
logger.exception("Exception occurred while loading %s", location)
pdata.close()
self._dirty = False
def handle_migration(db, pdata, oldversion, newversion):
if oldversion == 1 and newversion == 2:
migrator = imp.load_source(
"from1to2", os.path.join(os.path.dirname(__file__), "from1to2.py"))
migrator.migrate(db, pdata, oldversion, newversion)
else:
raise common.VersionError("Don't know how to handle upgrade from " \
"music database version %s to %s."%(oldversion, newversion))
def handle_migration(db, pdata, oldversion, newversion):
if oldversion == 1 and newversion == 2:
from . import from1to2
from1to2.migrate(db, pdata, oldversion, newversion)
else:
raise common.VersionError("Don't know how to handle upgrade from "
"music database version %s to %s." %
(oldversion, newversion))
def save_to_location(self, location=None):
"""
Saves a pickled representation of this :class:`TrackDB` to the
specified location.
:param location: the location to save the data to
:type location: string
"""
if not self._dirty:
for track in self.tracks.values():
if track._track._dirty:
self._dirty = True
break
if not self._dirty:
return
if not location:
location = self.location
if not location:
raise AttributeError(
_("You did not specify a location to save the db"))
if self._saving:
return
self._saving = True
logger.debug("Saving %s DB to %s.", self.name, location)
try:
pdata = common.open_shelf(location)
if pdata.get('_dbversion', self._dbversion) > self._dbversion:
raise common.VersionError("DB was created on a newer Exaile.")
except Exception:
logger.exception("Failed to open music DB for writing.")
return
for attr in self.pickle_attrs:
# bad hack to allow saving of lists/dicts of Tracks
if 'tracks' == attr:
for k, track in self.tracks.items():
key = "tracks-%s" % track._key
if track._track._dirty or key not in pdata:
pdata[key] = (
track._track._pickles(),
track._key,
deepcopy(track._attrs),
)
else:
pdata[attr] = deepcopy(getattr(self, attr))
pdata['_dbversion'] = self._dbversion
for key in self._deleted_keys:
key = "tracks-%s" % key
if key in pdata:
del pdata[key]
pdata.sync()
pdata.close()
for track in self.tracks.values():
track._track._dirty = False
self._dirty = False
self._saving = False