|
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 2.1. |
|
8 |
|
9 __revision__ = "$Id: dep_util.py 58049 2007-09-08 00:34:17Z skip.montanaro $" |
|
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" % |
|
23 os.path.abspath(source)) |
|
24 if not os.path.exists(target): |
|
25 return 1 |
|
26 |
|
27 from stat import ST_MTIME |
|
28 mtime1 = os.stat(source)[ST_MTIME] |
|
29 mtime2 = os.stat(target)[ST_MTIME] |
|
30 |
|
31 return mtime1 > mtime2 |
|
32 |
|
33 # newer () |
|
34 |
|
35 |
|
36 def newer_pairwise (sources, targets): |
|
37 """Walk two filename lists in parallel, testing if each source is newer |
|
38 than its corresponding target. Return a pair of lists (sources, |
|
39 targets) where source is newer than target, according to the semantics |
|
40 of 'newer()'. |
|
41 """ |
|
42 if len(sources) != len(targets): |
|
43 raise ValueError, "'sources' and 'targets' must be same length" |
|
44 |
|
45 # build a pair of lists (sources, targets) where source is newer |
|
46 n_sources = [] |
|
47 n_targets = [] |
|
48 for i in range(len(sources)): |
|
49 if newer(sources[i], targets[i]): |
|
50 n_sources.append(sources[i]) |
|
51 n_targets.append(targets[i]) |
|
52 |
|
53 return (n_sources, n_targets) |
|
54 |
|
55 # newer_pairwise () |
|
56 |
|
57 |
|
58 def newer_group (sources, target, missing='error'): |
|
59 """Return true if 'target' is out-of-date with respect to any file |
|
60 listed in 'sources'. In other words, if 'target' exists and is newer |
|
61 than every file in 'sources', return false; otherwise return true. |
|
62 'missing' controls what we do when a source file is missing; the |
|
63 default ("error") is to blow up with an OSError from inside 'stat()'; |
|
64 if it is "ignore", we silently drop any missing source files; if it is |
|
65 "newer", any missing source files make us assume that 'target' is |
|
66 out-of-date (this is handy in "dry-run" mode: it'll make you pretend to |
|
67 carry out commands that wouldn't work because inputs are missing, but |
|
68 that doesn't matter because you're not actually going to run the |
|
69 commands). |
|
70 """ |
|
71 # If the target doesn't even exist, then it's definitely out-of-date. |
|
72 if not os.path.exists(target): |
|
73 return 1 |
|
74 |
|
75 # Otherwise we have to find out the hard way: if *any* source file |
|
76 # is more recent than 'target', then 'target' is out-of-date and |
|
77 # we can immediately return true. If we fall through to the end |
|
78 # of the loop, then 'target' is up-to-date and we return false. |
|
79 from stat import ST_MTIME |
|
80 target_mtime = os.stat(target)[ST_MTIME] |
|
81 for source in sources: |
|
82 if not os.path.exists(source): |
|
83 if missing == 'error': # blow up when we stat() the file |
|
84 pass |
|
85 elif missing == 'ignore': # missing source dropped from |
|
86 continue # target's dependency list |
|
87 elif missing == 'newer': # missing source means target is |
|
88 return 1 # out-of-date |
|
89 |
|
90 source_mtime = os.stat(source)[ST_MTIME] |
|
91 if source_mtime > target_mtime: |
|
92 return 1 |
|
93 else: |
|
94 return 0 |
|
95 |
|
96 # newer_group () |