cpython/Lib/distutils/dep_util.py
Greg Ward aebf706b4e Reorganization: ripped util.py to shreds, creating in the process:
- file_util.py: operations on single files
  - dir_util.py: operations on whole directories or directory trees
  - dep_util.py: simple timestamp-based dependency analysis
  - archive_util.py: creation of archive (tar, zip, ...) files
The functions left in util.py are miscellany that don't fit in any of the
new files.
2000-04-04 02:05:59 +00:00

117 lines
4.2 KiB
Python

"""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."""
# created 2000/04/03, Greg Ward (extracted from util.py)
__revision__ = "$Id$"
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'):
"""Return true if 'target' is out-of-date with respect to any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 ()
# XXX this isn't used anywhere, and worse, it has the same name as a method
# in Command with subtly different semantics. (This one just has one
# source -> one dest; that one has many sources -> one dest.) Nuke it?
def make_file (src, dst, func, args,
verbose=0, update_message=None, noupdate_message=None):
"""Makes 'dst' from 'src' (both filenames) by calling 'func' with
'args', but only if it needs to: i.e. if 'dst' does not exist or
'src' is newer than 'dst'."""
if newer (src, dst):
if verbose and update_message:
print update_message
apply (func, args)
else:
if verbose and noupdate_message:
print noupdate_message
# make_file ()