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[python/dscho.git] / Lib / distutils / file_util.py
blobb3d9d54ec025691f0f2232dcfa2348b1309fd2a4
1 """distutils.file_util
3 Utility functions for operating on single files.
4 """
6 __revision__ = "$Id$"
8 import os
9 from distutils.errors import DistutilsFileError
10 from distutils import log
12 # for generating verbose output in 'copy_file()'
13 _copy_action = {None: 'copying',
14 'hard': 'hard linking',
15 'sym': 'symbolically linking'}
18 def _copy_file_contents(src, dst, buffer_size=16*1024):
19 """Copy the file 'src' to 'dst'.
21 Both must be filenames. Any error opening either file, reading from
22 'src', or writing to 'dst', raises DistutilsFileError. Data is
23 read/written in chunks of 'buffer_size' bytes (default 16k). No attempt
24 is made to handle anything apart from regular files.
25 """
26 # Stolen from shutil module in the standard library, but with
27 # custom error-handling added.
28 fsrc = None
29 fdst = None
30 try:
31 try:
32 fsrc = open(src, 'rb')
33 except os.error, (errno, errstr):
34 raise DistutilsFileError("could not open '%s': %s" % (src, errstr))
36 if os.path.exists(dst):
37 try:
38 os.unlink(dst)
39 except os.error, (errno, errstr):
40 raise DistutilsFileError(
41 "could not delete '%s': %s" % (dst, errstr))
43 try:
44 fdst = open(dst, 'wb')
45 except os.error, (errno, errstr):
46 raise DistutilsFileError(
47 "could not create '%s': %s" % (dst, errstr))
49 while 1:
50 try:
51 buf = fsrc.read(buffer_size)
52 except os.error, (errno, errstr):
53 raise DistutilsFileError(
54 "could not read from '%s': %s" % (src, errstr))
56 if not buf:
57 break
59 try:
60 fdst.write(buf)
61 except os.error, (errno, errstr):
62 raise DistutilsFileError(
63 "could not write to '%s': %s" % (dst, errstr))
65 finally:
66 if fdst:
67 fdst.close()
68 if fsrc:
69 fsrc.close()
71 def copy_file(src, dst, preserve_mode=1, preserve_times=1, update=0,
72 link=None, verbose=1, dry_run=0):
73 """Copy a file 'src' to 'dst'.
75 If 'dst' is a directory, then 'src' is copied there with the same name;
76 otherwise, it must be a filename. (If the file exists, it will be
77 ruthlessly clobbered.) If 'preserve_mode' is true (the default),
78 the file's mode (type and permission bits, or whatever is analogous on
79 the current platform) is copied. If 'preserve_times' is true (the
80 default), the last-modified and last-access times are copied as well.
81 If 'update' is true, 'src' will only be copied if 'dst' does not exist,
82 or if 'dst' does exist but is older than 'src'.
84 'link' allows you to make hard links (os.link) or symbolic links
85 (os.symlink) instead of copying: set it to "hard" or "sym"; if it is
86 None (the default), files are copied. Don't set 'link' on systems that
87 don't support it: 'copy_file()' doesn't check if hard or symbolic
88 linking is available.
90 Under Mac OS, uses the native file copy function in macostools; on
91 other systems, uses '_copy_file_contents()' to copy file contents.
93 Return a tuple (dest_name, copied): 'dest_name' is the actual name of
94 the output file, and 'copied' is true if the file was copied (or would
95 have been copied, if 'dry_run' true).
96 """
97 # XXX if the destination file already exists, we clobber it if
98 # copying, but blow up if linking. Hmmm. And I don't know what
99 # macostools.copyfile() does. Should definitely be consistent, and
100 # should probably blow up if destination exists and we would be
101 # changing it (ie. it's not already a hard/soft link to src OR
102 # (not update) and (src newer than dst).
104 from distutils.dep_util import newer
105 from stat import ST_ATIME, ST_MTIME, ST_MODE, S_IMODE
107 if not os.path.isfile(src):
108 raise DistutilsFileError(
109 "can't copy '%s': doesn't exist or not a regular file" % src)
111 if os.path.isdir(dst):
112 dir = dst
113 dst = os.path.join(dst, os.path.basename(src))
114 else:
115 dir = os.path.dirname(dst)
117 if update and not newer(src, dst):
118 if verbose >= 1:
119 log.debug("not copying %s (output up-to-date)", src)
120 return dst, 0
122 try:
123 action = _copy_action[link]
124 except KeyError:
125 raise ValueError("invalid value '%s' for 'link' argument" % link)
127 if verbose >= 1:
128 if os.path.basename(dst) == os.path.basename(src):
129 log.info("%s %s -> %s", action, src, dir)
130 else:
131 log.info("%s %s -> %s", action, src, dst)
133 if dry_run:
134 return (dst, 1)
136 # If linking (hard or symbolic), use the appropriate system call
137 # (Unix only, of course, but that's the caller's responsibility)
138 if link == 'hard':
139 if not (os.path.exists(dst) and os.path.samefile(src, dst)):
140 os.link(src, dst)
141 elif link == 'sym':
142 if not (os.path.exists(dst) and os.path.samefile(src, dst)):
143 os.symlink(src, dst)
145 # Otherwise (non-Mac, not linking), copy the file contents and
146 # (optionally) copy the times and mode.
147 else:
148 _copy_file_contents(src, dst)
149 if preserve_mode or preserve_times:
150 st = os.stat(src)
152 # According to David Ascher <da@ski.org>, utime() should be done
153 # before chmod() (at least under NT).
154 if preserve_times:
155 os.utime(dst, (st[ST_ATIME], st[ST_MTIME]))
156 if preserve_mode:
157 os.chmod(dst, S_IMODE(st[ST_MODE]))
159 return (dst, 1)
161 # XXX I suspect this is Unix-specific -- need porting help!
162 def move_file (src, dst, verbose=1, dry_run=0):
163 """Move a file 'src' to 'dst'.
165 If 'dst' is a directory, the file will be moved into it with the same
166 name; otherwise, 'src' is just renamed to 'dst'. Return the new
167 full name of the file.
169 Handles cross-device moves on Unix using 'copy_file()'. What about
170 other systems???
172 from os.path import exists, isfile, isdir, basename, dirname
173 import errno
175 if verbose >= 1:
176 log.info("moving %s -> %s", src, dst)
178 if dry_run:
179 return dst
181 if not isfile(src):
182 raise DistutilsFileError("can't move '%s': not a regular file" % src)
184 if isdir(dst):
185 dst = os.path.join(dst, basename(src))
186 elif exists(dst):
187 raise DistutilsFileError(
188 "can't move '%s': destination '%s' already exists" %
189 (src, dst))
191 if not isdir(dirname(dst)):
192 raise DistutilsFileError(
193 "can't move '%s': destination '%s' not a valid path" % \
194 (src, dst))
196 copy_it = 0
197 try:
198 os.rename(src, dst)
199 except os.error, (num, msg):
200 if num == errno.EXDEV:
201 copy_it = 1
202 else:
203 raise DistutilsFileError(
204 "couldn't move '%s' to '%s': %s" % (src, dst, msg))
206 if copy_it:
207 copy_file(src, dst, verbose=verbose)
208 try:
209 os.unlink(src)
210 except os.error, (num, msg):
211 try:
212 os.unlink(dst)
213 except os.error:
214 pass
215 raise DistutilsFileError(
216 ("couldn't move '%s' to '%s' by copy/delete: " +
217 "delete '%s' failed: %s") %
218 (src, dst, src, msg))
219 return dst
222 def write_file (filename, contents):
223 """Create a file with the specified name and write 'contents' (a
224 sequence of strings without line terminators) to it.
226 f = open(filename, "w")
227 for line in contents:
228 f.write(line + "\n")
229 f.close()