Python Linecache Source code

The source code of linecache.py from Python 2.0 are here.

 from Import *

Get File Information

>>> Filestat = Os.stat ('README. TXT')>>> filestatnt.stat_result (st_mode=33206, st_ino=0l, st_dev=0, St_ Nlink=0, St_uid=0, St_gid=0, st_size=2623l, st_atime=1450607830l, st_mtime=1398844440l, St_ctime=1398844440L) >>> filestat.st_mtimeimport  statfromimport *>> > filestat[st_mtime]1398844440L

Notice Filesta.st_mtime is a float number and filestat[st_mtime] is a long number which is strange.

Each cache is a entry are a dictionary with Key=filename value= (size, mtime, lines, Fullnames) (line 91)

Cache is only updated when a cache miss occurs. (line 39)

Function Checkcache () is not called automatically and it seems, the user should call this function manually.

Source Code

1 """Cache lines from files.2 3 This is intended to read lines from modules imported--hence if a filename4 is not found, it would look down the module search path for a file by5 that name.6 """7 8 ImportSYS9 ImportOSTen  fromStatImport* One  A defgetline (filename, Lineno): -Lines =getlines (filename) -     if1 <= Lineno <=Len (lines): the         returnLines[lineno-1] -     Else: -         return "' -  +  - #The cache +  Acache = {}#The cache at  -  - defClearCache (): -     """Clear the cache entirely.""" -  -     GlobalCache inCache = {} -  to  + defgetlines (filename): -     """Get the lines for a file from the cache. the Update The cache if it doesn ' t contain an entry for this file already.""" *  $     ifcache.has_key (filename):Panax Notoginseng         returnCache[filename][2] -     Else: the         returnupdatecache (filename) +  A  the defCheckcache (): +     """Discard Cache entries that is out of date. - (this isn't checked upon each call!)""" $  $      forFileNameinchCache.keys (): -Size, Mtime, lines, FullName =Cache[filename] -         Try: theStat =Os.stat (FullName) -         exceptOs.error:Wuyi             delCache[filename] the             Continue -         ifSize <> Stat[st_size]orMtime <>Stat[st_mtime]: Wu             delCache[filename] -  About  $ defupdatecache (filename): -     """Update A cache entry and return its list of lines. - If something ' s wrong, print a message, discard the cache entry, - And return an empty list.""" A  +     ifcache.has_key (filename): the         delCache[filename] -     if  notFileNameorFilename[0] + filename[-1] = ='<>': $         return [] theFullName =filename the     Try: theStat =Os.stat (FullName) the     exceptos.error, msg: -         #Try looking through the module search path inbasename = os.path.split (filename) [1] the          forDirNameinchSys.path: theFullName =Os.path.join (dirname, basename) About             Try: theStat =Os.stat (FullName) the                  Break the             exceptOs.error: +                 Pass -         Else: the             #No LuckBayi ## print ' * * * * cannot stat ', filename, ': ', msg the             return [] the     Try: -fp = open (FullName,'R') -Lines =Fp.readlines () the fp.close () the     exceptIOError, msg: the ## print ' * * * * cannot open ', FullName, ': ', msg the         return [] -Size, Mtime =Stat[st_size], Stat[st_mtime] theCache[filename] =size, Mtime, lines, fullname the     returnLines

Python Linecache Source code