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from __future__ import generators
execfile("rorpiter.py")
#######################################################################
#
# destructive-stepping - Deal with side effects from traversing trees
#
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.
"""
def __init__(self, *args):
self.perms_delayed = self.times_delayed = None
RPath.__init__(self, *args)
def __getstate__(self):
"""Return picklable state. See RPath __getstate__."""
assert self.conn is Globals.local_connection # Can't pickle a conn
pickle_dict = {}
for attrib in ['index', 'data', 'perms_delayed', 'times_delayed',
'newperms', 'newtimes', 'path', 'base']:
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 delay_perm_writes(self):
"""Signal that permission writing should be delayed until the end"""
self.perms_delayed = 1
self.newperms = None
def delay_time_changes(self):
"""Signal that time changes should also be delayed until the end"""
self.times_delayed = 1
self.newtimes = None
def chmod(self, permissions):
"""Change permissions, delaying if self.perms_delayed is set"""
if self.perms_delayed:
self.newperms = 1
self.data['perms'] = permissions
else: RPath.chmod(self, permissions)
def chmod_bypass(self, permissions):
"""Change permissions without updating the data dictionary"""
self.conn.os.chmod(self.path, permissions)
self.perms_delayed = self.newperms = 1
def remember_times(self):
"""Mark times as changed so they can be restored later"""
self.times_delayed = self.newtimes = 1
def settime(self, accesstime, modtime):
"""Change times, delaying if self.times_delayed is set"""
if self.times_delayed:
self.newtimes = 1
self.data['atime'] = accesstime
self.data['mtime'] = modtime
else: RPath.settime(self, accesstime, modtime)
def settime_bypass(self, accesstime, modtime):
"""Change times without updating data dictionary"""
self.conn.os.utime(self.path, (accesstime, modtime))
def setmtime(self, modtime):
"""Change mtime, delaying if self.times_delayed is set"""
if self.times_delayed:
self.newtimes = 1
self.data['mtime'] = modtime
else: RPath.setmtime(self, modtime)
def setmtime_bypass(self, modtime):
"""Change mtime without updating data dictionary"""
self.conn.os.utime(self.path, (time.time(), modtime))
def restoretimes(self):
"""Write times in self.data back to file"""
RPath.settime(self, self.data['atime'], self.data['mtime'])
def restoreperms(self):
"""Write permissions in self.data back to file"""
RPath.chmod(self, self.data['perms'])
def write_changes(self):
"""Write saved up permission/time changes"""
if not self.lstat(): return # File has been deleted in meantime
if self.perms_delayed and self.newperms:
self.conn.os.chmod(self.path, self.getperms())
if self.times_delayed:
if self.data.has_key('atime'):
self.settime_bypass(self.getatime(), self.getmtime())
elif self.newtimes and self.data.has_key('mtime'):
self.setmtime_bypass(self.getmtime())
class DestructiveStepping:
"""Destructive stepping"""
def initialize(dsrpath, source):
"""Change permissions of dsrpath, possibly delay writes
Abort if we need to access something and can't. If the file
is on the source partition, just log warning and return true.
Return false if everything good to go.
"""
if not source or Globals.change_source_perms:
dsrpath.delay_perm_writes()
def warn(err):
Log("Received error '%s' when dealing with file %s, skipping..."
% (err, dsrpath.path), 1)
def abort():
Log.FatalError("Missing access to file %s - aborting." %
dsrpath.path)
def try_chmod(perms):
"""Try to change the perms. If fail, return error."""
try: dsrpath.chmod_bypass(perms)
except os.error, err: return err
return None
if dsrpath.isreg() and not dsrpath.readable():
if source:
if Globals.change_source_perms and dsrpath.isowner():
err = try_chmod(0400)
if err:
warn(err)
return 1
else:
warn("No read permissions")
return 1
elif not Globals.change_mirror_perms or try_chmod(0600): abort()
elif dsrpath.isdir():
if source and (not dsrpath.readable() or not dsrpath.executable()):
if Globals.change_source_perms and dsrpath.isowner():
err = try_chmod(0500)
if err:
warn(err)
return 1
else:
warn("No read or exec permissions")
return 1
elif not source and not dsrpath.hasfullperms():
if Globals.change_mirror_perms: try_chmod(0700)
# Permissions above; now try to preserve access times if necessary
if (source and (Globals.preserve_atime or
Globals.change_source_perms) or
not source):
# These are the circumstances under which we will have to
# touch up a file's times after we are done with it
dsrpath.remember_times()
return None
def Finalizer(initial_state = None):
"""Return a 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.
"""
return IterTreeReducer(lambda x: None, lambda x,y: None, None,
lambda dsrpath, x, y: dsrpath.write_changes(),
initial_state)
MakeStatic(DestructiveStepping)
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