wxPython/distutils/dep_util.py

   1 """distutils.dep_util
   2
   3 Utility functions for simple, timestamp-based dependency of files
   4 and groups of files; also, function based entirely on such
   5 timestamp dependency analysis."""
   6
   7 # This module should be kept compatible with Python 1.5.2.
   8
   9 __revision__ = "$Id$"
  10
  11 import os
  12 from distutils.errors import DistutilsFileError
  13
  14
  15 def newer (source, target):
  16     """Return true if 'source' exists and is more recently modified than
  17     'target', or if 'source' exists and 'target' doesn't.  Return false if
  18     both exist and 'target' is the same age or younger than 'source'.
  19     Raise DistutilsFileError if 'source' does not exist.
  20     """
  21     if not os.path.exists(source):
  22         raise DistutilsFileError, "file '%s' does not exist" % source
  23     if not os.path.exists(target):
  24         return 1
  25
  26     from stat import ST_MTIME
  27     mtime1 = os.stat(source)[ST_MTIME]
  28     mtime2 = os.stat(target)[ST_MTIME]
  29
  30     return mtime1 > mtime2
  31
  32 # newer ()
  33
  34
  35 def newer_pairwise (sources, targets):
  36     """Walk two filename lists in parallel, testing if each source is newer
  37     than its corresponding target.  Return a pair of lists (sources,
  38     targets) where source is newer than target, according to the semantics
  39     of 'newer()'.
  40     """
  41     if len(sources) != len(targets):
  42         raise ValueError, "'sources' and 'targets' must be same length"
  43
  44     # build a pair of lists (sources, targets) where  source is newer
  45     n_sources = []
  46     n_targets = []
  47     for i in range(len(sources)):
  48         if newer(sources[i], targets[i]):
  49             n_sources.append(sources[i])
  50             n_targets.append(targets[i])
  51
  52     return (n_sources, n_targets)
  53
  54 # newer_pairwise ()
  55
  56
  57 def newer_group (sources, target, missing='error'):
  58     """Return true if 'target' is out-of-date with respect to any file
  59     listed in 'sources'.  In other words, if 'target' exists and is newer
  60     than every file in 'sources', return false; otherwise return true.
  61     'missing' controls what we do when a source file is missing; the
  62     default ("error") is to blow up with an OSError from inside 'stat()';
  63     if it is "ignore", we silently drop any missing source files; if it is
  64     "newer", any missing source files make us assume that 'target' is
  65     out-of-date (this is handy in "dry-run" mode: it'll make you pretend to
  66     carry out commands that wouldn't work because inputs are missing, but
  67     that doesn't matter because you're not actually going to run the
  68     commands).
  69     """
  70     # If the target doesn't even exist, then it's definitely out-of-date.
  71     if not os.path.exists(target):
  72         return 1
  73
  74     # Otherwise we have to find out the hard way: if *any* source file
  75     # is more recent than 'target', then 'target' is out-of-date and
  76     # we can immediately return true.  If we fall through to the end
  77     # of the loop, then 'target' is up-to-date and we return false.
  78     from stat import ST_MTIME
  79     target_mtime = os.stat(target)[ST_MTIME]
  80     for source in sources:
  81         if not os.path.exists(source):
  82             if missing == 'error':      # blow up when we stat() the file
  83                 pass
  84             elif missing == 'ignore':   # missing source dropped from
  85                 continue                #  target's dependency list
  86             elif missing == 'newer':    # missing source means target is
  87                 return 1                #  out-of-date
  88
  89         source_mtime = os.stat(source)[ST_MTIME]
  90         if source_mtime > target_mtime:
  91             return 1
  92     else:
  93         return 0
  94
  95 # newer_group ()