Commit | Line | Data |
---|---|---|
86530b38 AT |
1 | """Cache lines from files. |
2 | ||
3 | This is intended to read lines from modules imported -- hence if a filename | |
4 | is not found, it will look down the module search path for a file by | |
5 | that name. | |
6 | """ | |
7 | ||
8 | import sys | |
9 | import os | |
10 | ||
11 | __all__ = ["getline", "clearcache", "checkcache"] | |
12 | ||
13 | def getline(filename, lineno): | |
14 | lines = getlines(filename) | |
15 | if 1 <= lineno <= len(lines): | |
16 | return lines[lineno-1] | |
17 | else: | |
18 | return '' | |
19 | ||
20 | ||
21 | # The cache | |
22 | ||
23 | cache = {} # The cache | |
24 | ||
25 | ||
26 | def clearcache(): | |
27 | """Clear the cache entirely.""" | |
28 | ||
29 | global cache | |
30 | cache = {} | |
31 | ||
32 | ||
33 | def getlines(filename): | |
34 | """Get the lines for a file from the cache. | |
35 | Update the cache if it doesn't contain an entry for this file already.""" | |
36 | ||
37 | if filename in cache: | |
38 | return cache[filename][2] | |
39 | else: | |
40 | return updatecache(filename) | |
41 | ||
42 | ||
43 | def checkcache(filename=None): | |
44 | """Discard cache entries that are out of date. | |
45 | (This is not checked upon each call!)""" | |
46 | ||
47 | if filename is None: | |
48 | filenames = cache.keys() | |
49 | else: | |
50 | if filename in cache: | |
51 | filenames = [filename] | |
52 | else: | |
53 | return | |
54 | ||
55 | for filename in filenames: | |
56 | size, mtime, lines, fullname = cache[filename] | |
57 | try: | |
58 | stat = os.stat(fullname) | |
59 | except os.error: | |
60 | del cache[filename] | |
61 | continue | |
62 | if size != stat.st_size or mtime != stat.st_mtime: | |
63 | del cache[filename] | |
64 | ||
65 | ||
66 | def updatecache(filename): | |
67 | """Update a cache entry and return its list of lines. | |
68 | If something's wrong, print a message, discard the cache entry, | |
69 | and return an empty list.""" | |
70 | ||
71 | if filename in cache: | |
72 | del cache[filename] | |
73 | if not filename or filename[0] + filename[-1] == '<>': | |
74 | return [] | |
75 | fullname = filename | |
76 | try: | |
77 | stat = os.stat(fullname) | |
78 | except os.error, msg: | |
79 | # Try looking through the module search path. | |
80 | basename = os.path.split(filename)[1] | |
81 | for dirname in sys.path: | |
82 | # When using imputil, sys.path may contain things other than | |
83 | # strings; ignore them when it happens. | |
84 | try: | |
85 | fullname = os.path.join(dirname, basename) | |
86 | except (TypeError, AttributeError): | |
87 | # Not sufficiently string-like to do anything useful with. | |
88 | pass | |
89 | else: | |
90 | try: | |
91 | stat = os.stat(fullname) | |
92 | break | |
93 | except os.error: | |
94 | pass | |
95 | else: | |
96 | # No luck | |
97 | ## print '*** Cannot stat', filename, ':', msg | |
98 | return [] | |
99 | try: | |
100 | fp = open(fullname, 'rU') | |
101 | lines = fp.readlines() | |
102 | fp.close() | |
103 | except IOError, msg: | |
104 | ## print '*** Cannot open', fullname, ':', msg | |
105 | return [] | |
106 | size, mtime = stat.st_size, stat.st_mtime | |
107 | cache[filename] = size, mtime, lines, fullname | |
108 | return lines |