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514 :: Making os.walkDirRec handle hidden files

• gradha (orginal) [2014-08-04T22:34:06+02:00] view original

  Current os.walkDirRec doesn't handle properly invisible files. It should ignore them by default, or at least allow to filter them, but this is not possible with the limited options of TPathComponent. Looking at the implementations of other procs using pcFile and friends it seems that an accepted pattern for linked files is to invoke system.succ on the enum. To support this the combination matrix explodes to:

  • pcFile
  • pcLinkToFile
  • pcHiddenFile
  • pcLinkToHiddenFile
  • pcDir
  • pcLinkToDir
  • pcHiddenDir
  • pcLinkToHiddenDir

  Maybe a clever trick would be to make sure all hidden variants can be masked on the same bit, which forces assigning specific values to these enums. What mask size is appropriate to assign presuming the hidden bit is the msb? Would these changes be accepted in the standard library breaking previous code? Any more new flags these procs should take care of?

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• Araq (orginal) [2014-08-04T23:07:23+02:00] view original

  You're not the first one who doesn't like the TPathComponent's design and the things that come with it. That said, I think walkDirRec is just fine and invisible files are stupid enough to begin with. Instead of the matrix explosion we can simply add a proc isHidden(filename: string): bool that you can query. Not the most efficient thing to do, but I really dislike breaking perfectly fine code only to make programmers decide what to do with a link to some hidden directory...

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• Varriount (orginal) [2014-08-06T01:03:41+02:00] view original

  What I've been wanting to do for a while is write an updated walkDirRec which gets all files, but returns the entire file's information. The signature could be something like:

  
  iterator walkPath(path: string, follow, filter: set[TPathComponent]): FileInfo
    ## Walks the directory `path` for files, returning files who are of the type specified by `filter` and
    ## following files of the type specified by `follow`. Path components in `follow` that cannot be followed
    ## (like pcFile and pcLinkToFile) are ignored.
  Run

  You could also take a callback based approach to file filtering:

  
  type fileCallback = proc (info:FileInfo): tuple[follow, filter: bool]
  proc walkPath(path: string, callback: fileCallback)
    ## Walks the directory `path` for files, calling `callback` with each file found. The tuple the callback returns determines
    ## whether the procedure continues following a path or continues at all.
  Run

  The procedures above allows recursive and non-recursive behavior, following symlinks, file filtering etc. It doesn't take into account hidden/non-hidden files, but this could be added. Actually, whether a file is hidden or not is found out by getFileInfo, but the information isn't exposed, since on Windows being 'hidden' is an attribute, and on Unix-like systems it's a tradition brought about by a naming scheme.

  Any suggestions/improvements?

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• Araq (orginal) [2014-08-06T15:40:10+02:00] view original

  Any suggestions/improvements?

  Sets are cooler than callbacks. ;-)

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