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from __future__ import generators
execfile("rorpiter.py")
#######################################################################
#
# destructive-stepping - Deal with side effects from traversing trees
#
class DSRPathError(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, *args):
"""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 len(args) == 2 and isinstance(args[0], RPath):
rp = args[0]
RPath.__init__(self, rp.conn, rp.base, rp.index)
else: RPath.__init__(self, *args)
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
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.getmtime()
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 not source or Globals.change_source_perms and self.isowner():
self.chmod_bypass(0400)
else: self.warn("No read permissions")
elif self.isdir():
if source and (not self.readable() or self.executable()):
if Globals.change_source_perms and self.isowner():
self.chmod_bypass(0500)
else: warn("No read or exec permission")
elif not source and 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 DSRPathError(self.path)
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', 'delay_perms', 'newperms',
'delay_atime', 'newatime',
'delay_mtime', 'newmtime',
'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 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 chmod_bypass(self, permissions):
"""Change permissions without updating the data dictionary"""
self.delay_perms = 1
if self.newperms is None: self.newperms = self.getperms()
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 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:
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)
class DestructiveSteppingFinalizer(IterTreeReducer):
"""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.
"""
def start_process(self, index, dsrpath):
self.dsrpath = dsrpath
def end_process(self):
self.dsrpath.write_changes()
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