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# Copyright 2002 Ben Escoto
#
# This file is part of rdiff-backup.
#
# rdiff-backup 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, Inc., 675 Mass Ave, Cambridge MA
# 02139, USA; either version 2 of the License, or (at your option) any
# later version; incorporated herein by reference.
"""Deal with side effects from traversing trees"""
from __future__ import generators
import types
from rpath import *
from lazy import *
class DSRPPermError(Exception):
"""Exception used when a DSRPath can't get sufficient permissions"""
pass
class DSRPath(RPath):
"""Destructive Stepping RPath
Sometimes when we traverse the directory tree, even when we just
want to read files, we have to change things, like the permissions
of a file or directory in order to read it, or the file's access
times. This class is like an RPath, but the permission and time
modifications are delayed, so that they can be done at the very
end when they won't be disturbed later.
Here are the new class variables:
delay_perms - true iff future perm changes should be delayed
newperms - holds the perm values while they are delayed
delay_atime - true iff some atime change are being delayed
newatime - holds the new atime
delay_mtime - true if some mtime change is being delayed
newmtime - holds the new mtime
"""
def __init__(self, source, conn_or_rp, base = 0, index = ()):
"""Initialize DSRP
Source should be true iff the DSRPath is taken from the
"source" partition and thus settings like
Globals.change_source_perms should be paid attention to.
If args is [rpath], return the dsrpath equivalent of rpath,
otherwise use the same arguments as the RPath initializer.
"""
if base == 0:
assert isinstance(conn_or_rp, RPath)
RPath.__init__(self, conn_or_rp.conn,
conn_or_rp.base, conn_or_rp.index)
else: RPath.__init__(self, conn_or_rp, base, index)
if source != "bypass":
# "bypass" val is used when unpackaging over connection
assert source is None or source is 1
self.source = source
self.set_delays(source)
self.set_init_perms(source)
def set_delays(self, source):
"""Delay writing permissions and times where appropriate"""
if not source or Globals.change_source_perms:
self.delay_perms, self.newperms = 1, None
else: self.delay_perms = None
if Globals.preserve_atime:
self.delay_atime = 1
# Now get atime right away if possible
if self.data.has_key('atime'): self.newatime = self.data['atime']
else: self.newatime = None
else: self.delay_atime = None
if source:
self.delay_mtime = None # we'll never change mtime of source file
else:
self.delay_mtime = 1
# Save mtime now for a dir, because it might inadvertantly change
if self.isdir(): self.newmtime = self.data['mtime']
else: self.newmtime = None
def set_init_perms(self, source):
"""If necessary, change permissions to ensure access"""
if self.isreg() and not self.readable():
if (source and Globals.change_source_perms or
not source and Globals.change_mirror_perms):
self.chmod_bypass(0400)
elif self.isdir():
if source and Globals.change_source_perms:
if not self.readable() or not self.executable():
self.chmod_bypass(0500)
elif not source and Globals.change_mirror_perms:
if not self.hasfullperms(): self.chmod_bypass(0700)
def warn(self, err):
Log("Received error '%s' when dealing with file %s, skipping..."
% (err, self.path), 1)
raise DSRPPermError(self.path)
def __getstate__(self):
"""Return picklable state. See RPath __getstate__."""
assert self.conn is Globals.local_connection # Can't pickle a conn
return self.getstatedict()
def getstatedict(self):
"""Return dictionary containing the attributes we can save"""
pickle_dict = {}
for attrib in ['index', 'data', 'delay_perms', 'newperms',
'delay_atime', 'newatime',
'delay_mtime', 'newmtime',
'path', 'base', 'source']:
if self.__dict__.has_key(attrib):
pickle_dict[attrib] = self.__dict__[attrib]
return pickle_dict
def __setstate__(self, pickle_dict):
"""Set state from object produced by getstate"""
self.conn = Globals.local_connection
for attrib in pickle_dict.keys():
self.__dict__[attrib] = pickle_dict[attrib]
def chmod(self, permissions):
"""Change permissions, delaying if self.perms_delayed is set"""
if self.delay_perms: self.newperms = self.data['perms'] = permissions
else: RPath.chmod(self, permissions)
def getperms(self):
"""Return dsrp's intended permissions"""
if self.delay_perms and self.newperms is not None:
return self.newperms
else: return self.data['perms']
def chmod_bypass(self, permissions):
"""Change permissions without updating the data dictionary"""
self.delay_perms = 1
if self.newperms is None: self.newperms = self.getperms()
Log("DSRP: Perm bypass %s to %o" % (self.path, permissions), 8)
self.conn.os.chmod(self.path, permissions)
def settime(self, accesstime, modtime):
"""Change times, delaying if self.times_delayed is set"""
if self.delay_atime: self.newatime = self.data['atime'] = accesstime
if self.delay_mtime: self.newmtime = self.data['mtime'] = modtime
if not self.delay_atime or not self.delay_mtime:
RPath.settime(self, accesstime, modtime)
def setmtime(self, modtime):
"""Change mtime, delaying if self.times_delayed is set"""
if self.delay_mtime: self.newmtime = self.data['mtime'] = modtime
else: RPath.setmtime(self, modtime)
def getmtime(self):
"""Return dsrp's intended modification time"""
if self.delay_mtime and self.newmtime is not None:
return self.newmtime
else: return self.data['mtime']
def getatime(self):
"""Return dsrp's intended access time"""
if self.delay_atime and self.newatime is not None:
return self.newatime
else: return self.data['atime']
def write_changes(self):
"""Write saved up permission/time changes"""
if not self.lstat(): return # File has been deleted in meantime
if self.delay_perms and self.newperms is not None:
Log("Finalizing permissions of dsrp %s to %s" %
(self.path, self.newperms), 8)
RPath.chmod(self, self.newperms)
do_atime = self.delay_atime and self.newatime is not None
do_mtime = self.delay_mtime and self.newmtime is not None
if do_atime and do_mtime:
RPath.settime(self, self.newatime, self.newmtime)
elif do_atime and not do_mtime:
RPath.settime(self, self.newatime, self.getmtime())
elif not do_atime and do_mtime:
RPath.setmtime(self, self.newmtime)
def newpath(self, newpath, index = ()):
"""Return similar DSRPath but with new path"""
return self.__class__(self.source, self.conn, newpath, index)
def append(self, ext):
"""Return similar DSRPath with new extension"""
return self.__class__(self.source, self.conn, self.base,
self.index + (ext,))
def new_index(self, index):
"""Return similar DSRPath with new index"""
return self.__class__(self.source, self.conn, self.base, index)
class DestructiveSteppingFinalizer(ErrorITR):
"""Finalizer that can work on an iterator of dsrpaths
The reason we have to use an IterTreeReducer is that some files
should be updated immediately, but for directories we sometimes
need to update all the files in the directory before finally
coming back to it.
"""
dsrpath = None
def start_process(self, index, dsrpath):
self.dsrpath = dsrpath
def end_process(self):
if self.dsrpath: self.dsrpath.write_changes()
from log import *
from robust import *
import Globals
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