1 # Copyright (c) 2002-2009 Zooko Wilcox-O'Hearn
2 # This file is part of pyutil; see README.txt for licensing terms.
5 Futz with files like a pro.
8 import sys, exceptions, os, stat, tempfile, time
10 from twisted.python import log
12 def rename(src, dst, tries=4, basedelay=0.1):
13 """ Here is a superkludge to workaround the fact that occasionally on
14 Windows some other process (e.g. an anti-virus scanner, a local search
15 engine, etc.) is looking at your file when you want to delete or move it,
16 and hence you can't. The horrible workaround is to sit and spin, trying
17 to delete it, for a short time and then give up.
19 With the default values of tries and basedelay this can block for less
22 @param tries: number of tries -- each time after the first we wait twice
23 as long as the previous wait
24 @param basedelay: how long to wait before the second try
26 for i in range(tries-1):
28 return os.rename(src, dst)
29 except EnvironmentError, le:
30 # XXX Tighten this to check if this is a permission denied error (possibly due to another Windows process having the file open and execute the superkludge only in this case.
31 log.msg("XXX KLUDGE Attempting to move file %s => %s; got %s; sleeping %s seconds" % (src, dst, le, basedelay,))
34 return os.rename(src, dst) # The last try.
36 def remove(f, tries=4, basedelay=0.1):
37 """ Here is a superkludge to workaround the fact that occasionally on
38 Windows some other process (e.g. an anti-virus scanner, a local search
39 engine, etc.) is looking at your file when you want to delete or move it,
40 and hence you can't. The horrible workaround is to sit and spin, trying
41 to delete it, for a short time and then give up.
43 With the default values of tries and basedelay this can block for less
46 @param tries: number of tries -- each time after the first we wait twice
47 as long as the previous wait
48 @param basedelay: how long to wait before the second try
51 os.chmod(f, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
54 for i in range(tries-1):
57 except EnvironmentError, le:
58 # XXX Tighten this to check if this is a permission denied error (possibly due to another Windows process having the file open and execute the superkludge only in this case.
59 if not os.path.exists(f):
61 log.msg("XXX KLUDGE Attempting to remove file %s; got %s; sleeping %s seconds" % (f, le, basedelay,))
64 return os.remove(f) # The last try.
66 class ReopenableNamedTemporaryFile:
68 This uses tempfile.mkstemp() to generate a secure temp file. It then closes
69 the file, leaving a zero-length file as a placeholder. You can get the
70 filename with ReopenableNamedTemporaryFile.name. When the
71 ReopenableNamedTemporaryFile instance is garbage collected or its shutdown()
72 method is called, it deletes the file.
74 def __init__(self, *args, **kwargs):
75 fd, self.name = tempfile.mkstemp(*args, **kwargs)
79 return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
82 return self.__repr__()
90 class NamedTemporaryDirectory:
92 This calls tempfile.mkdtemp(), stores the name of the dir in
93 self.name, and rmrf's the dir when it gets garbage collected or
96 def __init__(self, cleanup=True, *args, **kwargs):
97 """ If cleanup, then the directory will be rmrf'ed when the object is shutdown. """
98 self.cleanup = cleanup
99 self.name = tempfile.mkdtemp(*args, **kwargs)
102 return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
105 return self.__repr__()
112 traceback.print_exc()
115 if self.cleanup and hasattr(self, 'name'):
118 def make_dirs(dirname, mode=0777):
120 An idempotent version of os.makedirs(). If the dir already exists, do
121 nothing and return without raising an exception. If this call creates the
122 dir, return without raising an exception. If there is an error that
123 prevents creation or if the directory gets deleted after make_dirs() creates
124 it and before make_dirs() checks that it exists, raise an exception.
128 os.makedirs(dirname, mode)
132 if not os.path.isdir(dirname):
135 raise exceptions.IOError, "unknown error prevented creation of directory, or deleted the directory immediately after creation: %s" % dirname # careful not to construct an IOError with a 2-tuple, as that has a special meaning...
139 A threadsafe and idempotent version of shutil.rmtree(). If the dir is
140 already gone, do nothing and return without raising an exception. If this
141 call removes the dir, return without raising an exception. If there is an
142 error that prevents deletion or if the directory gets created again after
143 rm_dir() deletes it and before rm_dir() checks that it is gone, raise an
148 os.chmod(dirname, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
149 for f in os.listdir(dirname):
150 fullname = os.path.join(dirname, f)
151 if os.path.isdir(fullname):
156 except Exception, le:
157 # Ignore "No such file or directory"
158 if (not isinstance(le, OSError)) or le.args[0] != 2:
161 # Okay, now we've recursively removed everything, ignoring any "No
162 # such file or directory" errors, and collecting any other errors.
164 if os.path.exists(dirname):
168 raise OSError, "Failed to remove dir for unknown reason."
172 def remove_if_possible(f):
178 def open_or_create(fname, binarymode=True):
180 return open(fname, binarymode and "r+b" or "r+")
181 except EnvironmentError:
182 return open(fname, binarymode and "w+b" or "w+")
187 for root, dirs, files in os.walk(basedir):
189 fn = os.path.join(root, f)
190 size += os.path.getsize(fn)
194 def move_into_place(source, dest):
195 """Atomically replace a file, or as near to it as the platform allows.
196 The dest file may or may not exist."""
197 if "win32" in sys.platform.lower():
198 remove_if_possible(dest)
199 os.rename(source, dest)