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- """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."""
- 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" %
- os.path.abspath(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'):
- """Return true if 'target' is out-of-date with respect to any file
- listed in 'sources'. In other words, if 'target' exists and is newer
- than every file in 'sources', return false; otherwise return true.
- 'missing' controls what we do when a source file is missing; the
- default ("error") is to blow up with an OSError from inside 'stat()';
- if it is "ignore", we silently drop any missing source files; if it is
- "newer", any missing source files make us assume that 'target' is
- out-of-date (this is handy in "dry-run" mode: it'll make you pretend to
- carry out commands that wouldn't work because inputs are missing, but
- that doesn't matter because you're not actually going to run the
- commands).
- """
- # If the target doesn't even exist, then it's definitely out-of-date.
- if not os.path.exists(target):
- return 1
- # Otherwise we have to find out the hard way: if *any* source file
- # is more recent than 'target', then 'target' is out-of-date and
- # we can immediately return true. If we fall through to the end
- # of the loop, then 'target' is up-to-date and we return false.
- from stat import ST_MTIME
- target_mtime = os.stat(target)[ST_MTIME]
- for source in sources:
- if not os.path.exists(source):
- if missing == 'error': # blow up when we stat() the file
- pass
- elif missing == 'ignore': # missing source dropped from
- continue # target's dependency list
- elif missing == 'newer': # missing source means target is
- return 1 # out-of-date
- source_mtime = os.stat(source)[ST_MTIME]
- if source_mtime > target_mtime:
- return 1
- else:
- return 0
- # newer_group ()
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