source file: /home/buildslave/tahoe/edgy/build/src/allmydata/util/fileutil.py
file stats: 106 lines, 71 executed: 67.0% covered
coverage versus previous test: 0 lines added, 0 lines removed
1. """
2. Futz with files like a pro.
3. """
4.
5. import sys, exceptions, os, stat, tempfile, time
6.
7. from twisted.python import log
8.
9. def rename(src, dst, tries=4, basedelay=0.1):
10. """ Here is a superkludge to workaround the fact that occasionally on
11. Windows some other process (e.g. an anti-virus scanner, a local search
12. engine, etc.) is looking at your file when you want to delete or move it,
13. and hence you can't. The horrible workaround is to sit and spin, trying
14. to delete it, for a short time and then give up.
15.
16. With the default values of tries and basedelay this can block for less
17. than a second.
18.
19. @param tries: number of tries -- each time after the first we wait twice
20. as long as the previous wait
21. @param basedelay: how long to wait before the second try
22. """
23. for i in range(tries-1):
24. try:
25. return os.rename(src, dst)
26. except EnvironmentError, le:
27. # 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.
28. log.msg("XXX KLUDGE Attempting to move file %s => %s; got %s; sleeping %s seconds" % (src, dst, le, basedelay,))
29. time.sleep(basedelay)
30. basedelay *= 2
31. return os.rename(src, dst) # The last try.
32.
33. def remove(f, tries=4, basedelay=0.1):
34. """ Here is a superkludge to workaround the fact that occasionally on
35. Windows some other process (e.g. an anti-virus scanner, a local search
36. engine, etc.) is looking at your file when you want to delete or move it,
37. and hence you can't. The horrible workaround is to sit and spin, trying
38. to delete it, for a short time and then give up.
39.
40. With the default values of tries and basedelay this can block for less
41. than a second.
42.
43. @param tries: number of tries -- each time after the first we wait twice
44. as long as the previous wait
45. @param basedelay: how long to wait before the second try
46. """
47. try:
48. os.chmod(f, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
49. except:
50. pass
51. for i in range(tries-1):
52. try:
53. return os.remove(f)
54. except EnvironmentError, le:
55. # 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.
56. if not os.path.exists(f):
57. return
58. log.msg("XXX KLUDGE Attempting to remove file %s; got %s; sleeping %s seconds" % (f, le, basedelay,))
59. time.sleep(basedelay)
60. basedelay *= 2
61. return os.remove(f) # The last try.
62.
63. class ReopenableNamedTemporaryFile:
64. """
65. This uses tempfile.mkstemp() to generate a secure temp file. It then closes
66. the file, leaving a zero-length file as a placeholder. You can get the
67. filename with ReopenableNamedTemporaryFile.name. When the
68. ReopenableNamedTemporaryFile instance is garbage collected or its shutdown()
69. method is called, it deletes the file.
70. """
71. def __init__(self, *args, **kwargs):
72. fd, self.name = tempfile.mkstemp(*args, **kwargs)
73. os.close(fd)
74.
75. def __repr__(self):
76. return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
77.
78. def __str__(self):
79. return self.__repr__()
80.
81. def __del__(self):
82. self.shutdown()
83.
84. def shutdown(self):
85. remove(self.name)
86.
87. class NamedTemporaryDirectory:
88. """
89. This calls tempfile.mkdtemp(), stores the name of the dir in
90. self.name, and rmrf's the dir when it gets garbage collected or
91. "shutdown()".
92. """
93. def __init__(self, cleanup=True, *args, **kwargs):
94. """ If cleanup, then the directory will be rmrf'ed when the object is shutdown. """
95. self.cleanup = cleanup
96. self.name = tempfile.mkdtemp(*args, **kwargs)
97.
98. def __repr__(self):
99. return "<%s instance at %x %s>" % (self.__class__.__name__, id(self), self.name)
100.
101. def __str__(self):
102. return self.__repr__()
103.
104. def __del__(self):
105. try:
106. self.shutdown()
107. except:
108. import traceback
109. traceback.print_exc()
110.
111. def shutdown(self):
112. if self.cleanup and hasattr(self, 'name'):
113. rm_dir(self.name)
114.
115. def make_dirs(dirname, mode=0777):
116. """
117. An idempotent version of os.makedirs(). If the dir already exists, do
118. nothing and return without raising an exception. If this call creates the
119. dir, return without raising an exception. If there is an error that
120. prevents creation or if the directory gets deleted after make_dirs() creates
121. it and before make_dirs() checks that it exists, raise an exception.
122. """
123. tx = None
124. try:
125. os.makedirs(dirname, mode)
126. except OSError, x:
127. tx = x
128.
129. if not os.path.isdir(dirname):
130. if tx:
131. raise tx
132. 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...
133.
134. def rm_dir(dirname):
135. """
136. A threadsafe and idempotent version of shutil.rmtree(). If the dir is
137. already gone, do nothing and return without raising an exception. If this
138. call removes the dir, return without raising an exception. If there is an
139. error that prevents deletion or if the directory gets created again after
140. rm_dir() deletes it and before rm_dir() checks that it is gone, raise an
141. exception.
142. """
143. excs = []
144. try:
145. os.chmod(dirname, stat.S_IWRITE | stat.S_IEXEC | stat.S_IREAD)
146. for f in os.listdir(dirname):
147. fullname = os.path.join(dirname, f)
148. if os.path.isdir(fullname):
149. rm_dir(fullname)
150. else:
151. remove(fullname)
152. os.rmdir(dirname)
153. except Exception, le:
154. # Ignore "No such file or directory"
155. if (not isinstance(le, OSError)) or le.args[0] != 2:
156. excs.append(le)
157.
158. # Okay, now we've recursively removed everything, ignoring any "No
159. # such file or directory" errors, and collecting any other errors.
160.
161. if os.path.exists(dirname):
162. if len(excs) == 1:
163. raise excs[0]
164. if len(excs) == 0:
165. raise OSError, "Failed to remove dir for unknown reason."
166. raise OSError, excs
167.
168.
169. def remove_if_possible(f):
170. try:
171. remove(f)
172. except:
173. pass
174.
175. def open_or_create(fname, binarymode=True):
176. try:
177. return open(fname, binarymode and "r+b" or "r+")
178. except EnvironmentError:
179. return open(fname, binarymode and "w+b" or "w+")
180.
181. def du(basedir):
182. size = 0
183.
184. for root, dirs, files in os.walk(basedir):
185. for f in files:
186. fn = os.path.join(root, f)
187. size += os.path.getsize(fn)
188.
189. return size
190.
191. def move_into_place(source, dest):
192. """Atomically replace a file, or as near to it as the platform allows.
193. The dest file may or may not exist."""
194. if "win32" in sys.platform.lower():
195. remove_if_possible(dest)
196. os.rename(source, dest)