source: vendor/python/2.5/Lib/distutils/dep_util.py@ 3225

"""distutils.dep_util

Utility functions for simple, timestamp-based dependency of files
and groups of files; also, function based entirely on such
timestamp dependency analysis."""

# This module should be kept compatible with Python 2.1.

__revision__ = "$Id: dep_util.py 37828 2004-11-10 22:23:15Z loewis $"

import os
from distutils.errors import DistutilsFileError


def newer (source, target):
    """Return true if 'source' exists and is more recently modified than
    'target', or if 'source' exists and 'target' doesn't.  Return false if
    both exist and 'target' is the same age or younger than 'source'.
    Raise DistutilsFileError if 'source' does not exist.
    """
    if not os.path.exists(source):
        raise DistutilsFileError, "file '%s' does not exist" % source
    if not os.path.exists(target):
        return 1

    from stat import ST_MTIME
    mtime1 = os.stat(source)[ST_MTIME]
    mtime2 = os.stat(target)[ST_MTIME]

    return mtime1 > mtime2

# newer ()


def newer_pairwise (sources, targets):
    """Walk two filename lists in parallel, testing if each source is newer
    than its corresponding target.  Return a pair of lists (sources,
    targets) where source is newer than target, according to the semantics
    of 'newer()'.
    """
    if len(sources) != len(targets):
        raise ValueError, "'sources' and 'targets' must be same length"

    # build a pair of lists (sources, targets) where  source is newer
    n_sources = []
    n_targets = []
    for i in range(len(sources)):
        if newer(sources[i], targets[i]):
            n_sources.append(sources[i])
            n_targets.append(targets[i])

    return (n_sources, n_targets)

# newer_pairwise ()


def newer_group (sources, target, missing='error'):