file_util.py
"""distutils.file_util
Utility functions for operating on single files.
"""
__revision__ = "$Id$"
import os
from distutils.errors import DistutilsFileError
from distutils import log
# for generating verbose output in 'copy_file()'
_copy_action = { None: 'copying',
'hard': 'hard linking',
'sym': 'symbolically linking' }
def _copy_file_contents(src, dst, buffer_size=16*1024):
"""Copy the file 'src' to 'dst'; both must be filenames. Any error
opening either file, reading from 'src', or writing to 'dst', raises
DistutilsFileError. Data is read/written in chunks of 'buffer_size'
bytes (default 16k). No attempt is made to handle anything apart from
regular files.
"""
# Stolen from shutil module in the standard library, but with
# custom error-handling added.
fsrc = None
fdst = None
try:
try:
fsrc = open(src, 'rb')
except os.error as e:
(errno, errstr) = e
raise DistutilsFileError("could not open '%s': %s" % (src, errstr))
if os.path.exists(dst):
try:
os.unlink(dst)
except os.error as e:
(errno, errstr) = e
raise DistutilsFileError(
"could not delete '%s': %s" % (dst, errstr))
try:
fdst = open(dst, 'wb')
except os.error as e:
(errno, errstr) = e
raise DistutilsFileError(
"could not create '%s': %s" % (dst, errstr))
while True:
try:
buf = fsrc.read(buffer_size)
except os.error as e:
(errno, errstr) = e
raise DistutilsFileError(
"could not read from '%s': %s" % (src, errstr))
if not buf:
break
try:
fdst.write(buf)
except os.error as e:
(errno, errstr) = e
raise DistutilsFileError(
"could not write to '%s': %s" % (dst, errstr))
finally:
if fdst:
fdst.close()
if fsrc:
fsrc.close()
def copy_file(src, dst, preserve_mode=1, preserve_times=1, update=0,
link=None, verbose=0, dry_run=0):
"""Copy a file 'src' to 'dst'. If 'dst' is a directory, then 'src' is
copied there with the same name; otherwise, it must be a filename. (If
the file exists, it will be ruthlessly clobbered.) If 'preserve_mode'
is true (the default), the file's mode (type and permission bits, or
whatever is analogous on the current platform) is copied. If
'preserve_times' is true (the default), the last-modified and
last-access times are copied as well. If 'update' is true, 'src' will
only be copied if 'dst' does not exist, or if 'dst' does exist but is
older than 'src'.
'link' allows you to make hard links (os.link) or symbolic links
(os.symlink) instead of copying: set it to "hard" or "sym"; if it is
None (the default), files are copied. Don't set 'link' on systems that
don't support it: 'copy_file()' doesn't check if hard or symbolic
linking is available.
Under Mac OS, uses the native file copy function in macostools; on
other systems, uses '_copy_file_contents()' to copy file contents.
Return a tuple (dest_name, copied): 'dest_name' is the actual name of
the output file, and 'copied' is true if the file was copied (or would
have been copied, if 'dry_run' true).
"""
# XXX if the destination file already exists, we clobber it if
# copying, but blow up if linking. Hmmm. And I don't know what
# macostools.copyfile() does. Should definitely be consistent, and
# should probably blow up if destination exists and we would be
# changing it (ie. it's not already a hard/soft link to src OR
# (not update) and (src newer than dst).
from distutils.dep_util import newer
from stat import ST_ATIME, ST_MTIME, ST_MODE, S_IMODE
if not os.path.isfile(src):
raise DistutilsFileError(
"can't copy '%s': doesn't exist or not a regular file" % src)
if os.path.isdir(dst):
dir = dst
dst = os.path.join(dst, os.path.basename(src))
else:
dir = os.path.dirname(dst)
if update and not newer(src, dst):
log.debug("not copying %s (output up-to-date)", src)
return (dst, 0)
try:
action = _copy_action[link]
except KeyError:
raise ValueError("invalid value '%s' for 'link' argument" % link)
if os.path.basename(dst) == os.path.basename(src):
log.info("%s %s -> %s", action, src, dir)
else:
log.info("%s %s -> %s", action, src, dst)
if dry_run:
return (dst, 1)
# On Mac OS, use the native file copy routine
if os.name == 'mac':
import macostools
try:
macostools.copy(src, dst, 0, preserve_times)
except os.error as exc:
raise DistutilsFileError(
"could not copy '%s' to '%s': %s" % (src, dst, exc.args[-1]))
# If linking (hard or symbolic), use the appropriate system call
# (Unix only, of course, but that's the caller's responsibility)
elif link == 'hard':
if not (os.path.exists(dst) and os.path.samefile(src, dst)):
os.link(src, dst)
elif link == 'sym':
if not (os.path.exists(dst) and os.path.samefile(src, dst)):
os.symlink(src, dst)
# Otherwise (non-Mac, not linking), copy the file contents and
# (optionally) copy the times and mode.
else:
_copy_file_contents(src, dst)
if preserve_mode or preserve_times:
st = os.stat(src)
# According to David Ascher <da@ski.org>, utime() should be done
# before chmod() (at least under NT).
if preserve_times:
os.utime(dst, (st[ST_ATIME], st[ST_MTIME]))
if preserve_mode:
os.chmod(dst, S_IMODE(st[ST_MODE]))
return (dst, 1)
# XXX I suspect this is Unix-specific -- need porting help!
def move_file (src, dst,
verbose=0,
dry_run=0):
"""Move a file 'src' to 'dst'. If 'dst' is a directory, the file will
be moved into it with the same name; otherwise, 'src' is just renamed
to 'dst'. Return the new full name of the file.
Handles cross-device moves on Unix using 'copy_file()'. What about
other systems???
"""
from os.path import exists, isfile, isdir, basename, dirname
import errno
log.info("moving %s -> %s", src, dst)
if dry_run:
return dst
if not isfile(src):
raise DistutilsFileError("can't move '%s': not a regular file" % src)
if isdir(dst):
dst = os.path.join(dst, basename(src))
elif exists(dst):
raise DistutilsFileError(
"can't move '%s': destination '%s' already exists" %
(src, dst))
if not isdir(dirname(dst)):
raise DistutilsFileError(
"can't move '%s': destination '%s' not a valid path" %
(src, dst))
copy_it = False
try:
os.rename(src, dst)
except os.error as e:
(num, msg) = e
if num == errno.EXDEV:
copy_it = True
else:
raise DistutilsFileError(
"couldn't move '%s' to '%s': %s" % (src, dst, msg))
if copy_it:
copy_file(src, dst)
try:
os.unlink(src)
except os.error as e:
(num, msg) = e
try:
os.unlink(dst)
except os.error:
pass
raise DistutilsFileError(
"couldn't move '%s' to '%s' by copy/delete: "
"delete '%s' failed: %s"
% (src, dst, src, msg))
return dst
def write_file (filename, contents):
"""Create a file with the specified name and write 'contents' (a
sequence of strings without line terminators) to it.
"""
f = open(filename, "w")
for line in contents:
f.write(line + "\n")
f.close()
