1 | """
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2 | Path operations common to more than one OS
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3 | Do not use directly. The OS specific modules import the appropriate
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4 | functions from this module themselves.
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5 | """
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6 | import os
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7 | import stat
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8 |
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9 | __all__ = ['commonprefix', 'exists', 'getatime', 'getctime', 'getmtime',
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10 | 'getsize', 'isdir', 'isfile']
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11 |
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12 |
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13 | try:
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14 | _unicode = unicode
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15 | except NameError:
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16 | # If Python is built without Unicode support, the unicode type
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17 | # will not exist. Fake one.
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18 | class _unicode(object):
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19 | pass
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20 |
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21 | # Does a path exist?
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22 | # This is false for dangling symbolic links on systems that support them.
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23 | def exists(path):
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24 | """Test whether a path exists. Returns False for broken symbolic links"""
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25 | try:
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26 | os.stat(path)
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27 | except os.error:
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28 | return False
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29 | return True
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30 |
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31 |
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32 | # This follows symbolic links, so both islink() and isdir() can be true
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33 | # for the same path on systems that support symlinks
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34 | def isfile(path):
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35 | """Test whether a path is a regular file"""
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36 | try:
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37 | st = os.stat(path)
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38 | except os.error:
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39 | return False
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40 | return stat.S_ISREG(st.st_mode)
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41 |
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42 |
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43 | # Is a path a directory?
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44 | # This follows symbolic links, so both islink() and isdir()
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45 | # can be true for the same path on systems that support symlinks
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46 | def isdir(s):
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47 | """Return true if the pathname refers to an existing directory."""
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48 | try:
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49 | st = os.stat(s)
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50 | except os.error:
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51 | return False
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52 | return stat.S_ISDIR(st.st_mode)
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53 |
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54 |
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55 | def getsize(filename):
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56 | """Return the size of a file, reported by os.stat()."""
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57 | return os.stat(filename).st_size
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58 |
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59 |
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60 | def getmtime(filename):
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61 | """Return the last modification time of a file, reported by os.stat()."""
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62 | return os.stat(filename).st_mtime
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63 |
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64 |
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65 | def getatime(filename):
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66 | """Return the last access time of a file, reported by os.stat()."""
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67 | return os.stat(filename).st_atime
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68 |
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69 |
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70 | def getctime(filename):
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71 | """Return the metadata change time of a file, reported by os.stat()."""
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72 | return os.stat(filename).st_ctime
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73 |
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74 |
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75 | # Return the longest prefix of all list elements.
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76 | def commonprefix(m):
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77 | "Given a list of pathnames, returns the longest common leading component"
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78 | if not m: return ''
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79 | s1 = min(m)
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80 | s2 = max(m)
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81 | for i, c in enumerate(s1):
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82 | if c != s2[i]:
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83 | return s1[:i]
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84 | return s1
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85 |
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86 | # Split a path in root and extension.
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87 | # The extension is everything starting at the last dot in the last
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88 | # pathname component; the root is everything before that.
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89 | # It is always true that root + ext == p.
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90 |
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91 | # Generic implementation of splitext, to be parametrized with
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92 | # the separators
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93 | def _splitext(p, sep, altsep, extsep):
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94 | """Split the extension from a pathname.
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95 |
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96 | Extension is everything from the last dot to the end, ignoring
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97 | leading dots. Returns "(root, ext)"; ext may be empty."""
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98 |
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99 | sepIndex = p.rfind(sep)
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100 | if altsep:
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101 | altsepIndex = p.rfind(altsep)
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102 | sepIndex = max(sepIndex, altsepIndex)
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103 |
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104 | dotIndex = p.rfind(extsep)
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105 | if dotIndex > sepIndex:
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106 | # skip all leading dots
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107 | filenameIndex = sepIndex + 1
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108 | while filenameIndex < dotIndex:
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109 | if p[filenameIndex] != extsep:
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110 | return p[:dotIndex], p[dotIndex:]
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111 | filenameIndex += 1
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112 |
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113 | return p, ''
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