| [2] | 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, module_globals=None):
|
|---|
| 14 | lines = getlines(filename, module_globals)
|
|---|
| 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, module_globals=None):
|
|---|
| 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, module_globals)
|
|---|
| 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| 44 | """Discard cache entries that are out of date.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 | if mtime is None:
|
|---|
| 58 | continue # no-op for files loaded via a __loader__
|
|---|
| 59 | try:
|
|---|
| 60 | stat = os.stat(fullname)
|
|---|
| 61 | except os.error:
|
|---|
| 62 | del cache[filename]
|
|---|
| 63 | continue
|
|---|
| 64 | if size != stat.st_size or mtime != stat.st_mtime:
|
|---|
| 65 | del cache[filename]
|
|---|
| 66 |
|
|---|
| 67 |
|
|---|
| 68 | def updatecache(filename, module_globals=None):
|
|---|
| 69 | """Update a cache entry and return its list of lines.
|
|---|
| 70 | If something's wrong, print a message, discard the cache entry,
|
|---|
| 71 | and return an empty list."""
|
|---|
| 72 |
|
|---|
| 73 | if filename in cache:
|
|---|
| 74 | del cache[filename]
|
|---|
| [391] | 75 | if not filename or (filename.startswith('<') and filename.endswith('>')):
|
|---|
| [2] | 76 | return []
|
|---|
| 77 |
|
|---|
| 78 | fullname = filename
|
|---|
| 79 | try:
|
|---|
| 80 | stat = os.stat(fullname)
|
|---|
| [391] | 81 | except OSError:
|
|---|
| [2] | 82 | basename = filename
|
|---|
| 83 |
|
|---|
| 84 | # Try for a __loader__, if available
|
|---|
| 85 | if module_globals and '__loader__' in module_globals:
|
|---|
| 86 | name = module_globals.get('__name__')
|
|---|
| 87 | loader = module_globals['__loader__']
|
|---|
| 88 | get_source = getattr(loader, 'get_source', None)
|
|---|
| 89 |
|
|---|
| 90 | if name and get_source:
|
|---|
| 91 | try:
|
|---|
| 92 | data = get_source(name)
|
|---|
| 93 | except (ImportError, IOError):
|
|---|
| 94 | pass
|
|---|
| 95 | else:
|
|---|
| 96 | if data is None:
|
|---|
| 97 | # No luck, the PEP302 loader cannot find the source
|
|---|
| 98 | # for this module.
|
|---|
| 99 | return []
|
|---|
| 100 | cache[filename] = (
|
|---|
| 101 | len(data), None,
|
|---|
| 102 | [line+'\n' for line in data.splitlines()], fullname
|
|---|
| 103 | )
|
|---|
| 104 | return cache[filename][2]
|
|---|
| 105 |
|
|---|
| 106 | # Try looking through the module search path, which is only useful
|
|---|
| 107 | # when handling a relative filename.
|
|---|
| 108 | if os.path.isabs(filename):
|
|---|
| 109 | return []
|
|---|
| 110 |
|
|---|
| 111 | for dirname in sys.path:
|
|---|
| 112 | # When using imputil, sys.path may contain things other than
|
|---|
| 113 | # strings; ignore them when it happens.
|
|---|
| 114 | try:
|
|---|
| 115 | fullname = os.path.join(dirname, basename)
|
|---|
| 116 | except (TypeError, AttributeError):
|
|---|
| 117 | # Not sufficiently string-like to do anything useful with.
|
|---|
| [391] | 118 | continue
|
|---|
| 119 | try:
|
|---|
| 120 | stat = os.stat(fullname)
|
|---|
| 121 | break
|
|---|
| 122 | except os.error:
|
|---|
| [2] | 123 | pass
|
|---|
| 124 | else:
|
|---|
| 125 | return []
|
|---|
| 126 | try:
|
|---|
| [391] | 127 | with open(fullname, 'rU') as fp:
|
|---|
| 128 | lines = fp.readlines()
|
|---|
| 129 | except IOError:
|
|---|
| [2] | 130 | return []
|
|---|
| [391] | 131 | if lines and not lines[-1].endswith('\n'):
|
|---|
| 132 | lines[-1] += '\n'
|
|---|
| [2] | 133 | size, mtime = stat.st_size, stat.st_mtime
|
|---|
| 134 | cache[filename] = size, mtime, lines, fullname
|
|---|
| 135 | return lines
|
|---|
