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96 lines
3.4 KiB
Python
96 lines
3.4 KiB
Python
"""distutils.dep_util
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Utility functions for simple, timestamp-based dependency of files
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and groups of files; also, function based entirely on such
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timestamp dependency analysis."""
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# This module should be kept compatible with Python 1.5.2.
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__revision__ = "$Id$"
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import os
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from distutils.errors import DistutilsFileError
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def newer (source, target):
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"""Return true if 'source' exists and is more recently modified than
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'target', or if 'source' exists and 'target' doesn't. Return false if
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both exist and 'target' is the same age or younger than 'source'.
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Raise DistutilsFileError if 'source' does not exist.
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"""
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if not os.path.exists(source):
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raise DistutilsFileError, "file '%s' does not exist" % source
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if not os.path.exists(target):
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return 1
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from stat import ST_MTIME
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mtime1 = os.stat(source)[ST_MTIME]
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mtime2 = os.stat(target)[ST_MTIME]
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return mtime1 > mtime2
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# newer ()
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def newer_pairwise (sources, targets):
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"""Walk two filename lists in parallel, testing if each source is newer
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than its corresponding target. Return a pair of lists (sources,
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targets) where source is newer than target, according to the semantics
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of 'newer()'.
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"""
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if len(sources) != len(targets):
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raise ValueError, "'sources' and 'targets' must be same length"
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# build a pair of lists (sources, targets) where source is newer
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n_sources = []
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n_targets = []
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for i in range(len(sources)):
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if newer(sources[i], targets[i]):
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n_sources.append(sources[i])
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n_targets.append(targets[i])
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return (n_sources, n_targets)
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# newer_pairwise ()
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def newer_group (sources, target, missing='error'):
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"""Return true if 'target' is out-of-date with respect to any file
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listed in 'sources'. In other words, if 'target' exists and is newer
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than every file in 'sources', return false; otherwise return true.
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'missing' controls what we do when a source file is missing; the
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default ("error") is to blow up with an OSError from inside 'stat()';
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if it is "ignore", we silently drop any missing source files; if it is
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"newer", any missing source files make us assume that 'target' is
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out-of-date (this is handy in "dry-run" mode: it'll make you pretend to
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carry out commands that wouldn't work because inputs are missing, but
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that doesn't matter because you're not actually going to run the
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commands).
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"""
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# If the target doesn't even exist, then it's definitely out-of-date.
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if not os.path.exists(target):
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return 1
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# Otherwise we have to find out the hard way: if *any* source file
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# is more recent than 'target', then 'target' is out-of-date and
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# we can immediately return true. If we fall through to the end
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# of the loop, then 'target' is up-to-date and we return false.
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from stat import ST_MTIME
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target_mtime = os.stat(target)[ST_MTIME]
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for source in sources:
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if not os.path.exists(source):
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if missing == 'error': # blow up when we stat() the file
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pass
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elif missing == 'ignore': # missing source dropped from
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continue # target's dependency list
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elif missing == 'newer': # missing source means target is
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return 1 # out-of-date
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source_mtime = os.stat(source)[ST_MTIME]
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if source_mtime > target_mtime:
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return 1
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else:
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return 0
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# newer_group ()
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