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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 # Does a path exist? |
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14 # This is false for dangling symbolic links on systems that support them. |
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15 def exists(path): |
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16 """Test whether a path exists. Returns False for broken symbolic links""" |
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17 try: |
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18 st = os.stat(path) |
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19 except os.error: |
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20 return False |
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21 return True |
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22 |
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23 |
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24 # This follows symbolic links, so both islink() and isdir() can be true |
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25 # for the same path ono systems that support symlinks |
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26 def isfile(path): |
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27 """Test whether a path is a regular file""" |
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28 try: |
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29 st = os.stat(path) |
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30 except os.error: |
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31 return False |
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32 return stat.S_ISREG(st.st_mode) |
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33 |
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34 |
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35 # Is a path a directory? |
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36 # This follows symbolic links, so both islink() and isdir() |
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37 # can be true for the same path on systems that support symlinks |
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38 def isdir(s): |
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39 """Return true if the pathname refers to an existing directory.""" |
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40 try: |
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41 st = os.stat(s) |
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42 except os.error: |
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43 return False |
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44 return stat.S_ISDIR(st.st_mode) |
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45 |
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46 |
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47 def getsize(filename): |
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48 """Return the size of a file, reported by os.stat().""" |
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49 return os.stat(filename).st_size |
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50 |
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51 |
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52 def getmtime(filename): |
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53 """Return the last modification time of a file, reported by os.stat().""" |
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54 return os.stat(filename).st_mtime |
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55 |
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56 |
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57 def getatime(filename): |
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58 """Return the last access time of a file, reported by os.stat().""" |
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59 return os.stat(filename).st_atime |
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60 |
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61 |
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62 def getctime(filename): |
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63 """Return the metadata change time of a file, reported by os.stat().""" |
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64 return os.stat(filename).st_ctime |
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65 |
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66 |
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67 # Return the longest prefix of all list elements. |
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68 def commonprefix(m): |
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69 "Given a list of pathnames, returns the longest common leading component" |
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70 if not m: return '' |
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71 s1 = min(m) |
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72 s2 = max(m) |
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73 for i, c in enumerate(s1): |
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74 if c != s2[i]: |
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75 return s1[:i] |
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76 return s1 |
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77 |
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78 # Split a path in root and extension. |
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79 # The extension is everything starting at the last dot in the last |
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80 # pathname component; the root is everything before that. |
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81 # It is always true that root + ext == p. |
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82 |
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83 # Generic implementation of splitext, to be parametrized with |
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84 # the separators |
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85 def _splitext(p, sep, altsep, extsep): |
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86 """Split the extension from a pathname. |
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87 |
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88 Extension is everything from the last dot to the end, ignoring |
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89 leading dots. Returns "(root, ext)"; ext may be empty.""" |
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90 |
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91 sepIndex = p.rfind(sep) |
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92 if altsep: |
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93 altsepIndex = p.rfind(altsep) |
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94 sepIndex = max(sepIndex, altsepIndex) |
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95 |
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96 dotIndex = p.rfind(extsep) |
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97 if dotIndex > sepIndex: |
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98 # skip all leading dots |
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99 filenameIndex = sepIndex + 1 |
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100 while filenameIndex < dotIndex: |
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101 if p[filenameIndex] != extsep: |
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102 return p[:dotIndex], p[dotIndex:] |
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103 filenameIndex += 1 |
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104 |
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105 return p, '' |