[wp-trac] [WordPress Trac] #11749: recurse_dirsize() leaves directories open

[WordPress Trac]

#11749: recurse_dirsize() leaves directories open
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 Reporter:  Denis-de-Bernardy  |       Owner:           
     Type:  defect (bug)       |      Status:  new      
 Priority:  normal             |   Milestone:  3.0      
Component:  Multisite          |     Version:  3.0      
 Severity:  normal             |    Keywords:  has-patch
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Comment(by hakre):

 Nice question. I just wondered as well and since the
 [http://www.php.net/manual/en/language.types.resource.php PHP
 documnetation] does offer both possiblities - automatically close with the
 garbage collector which can be a benefit for a functions local variables (
 :) ) or not for some types (persistent database connections e.g.) I
 thought it's a good Idea to do some tests.

 '''Stream Details'''

  Resource Type Name: Stream[[BR]]
  Created By: [http://www.php.net/manual/en/function.opendir.php opendir()]
 [[BR]]
  Used By: [http://www.php.net/manual/en/function.readdir.php readdir()],
 rewinddir()[[BR]]
  Destroyed By: [http://www.php.net/manual/en/function.closedir.php
 closedir()] [[BR]]
  Definition: Dir handle

 '''Testing Log'''
  1. Closing a directory handle does not destroy the actual resource but it
 does change the type from ''stream'' to ''Unknown''. Since the stream is
 destroyed I assume that some resources are freed.
  2. Directories opened in functions do stay open even if returned from the
 function. So unsetting the directory handle variable does not make any
 difference, even not when explicitly done with = NULL or unset().
  3. Directories explicitly closed in functions will close the directory. A
 next call to readdir will return false and raise a warning ( {{{Warning:
 readdir(): no Directory resource supplied in __FILE__ on line __LINE__}}}
 ).
  4. Directories fully read will not autmatically close the directory
 handle.
  5. Using closedir() on a resource other than a Directory Resource (Type
 Stream, Dir Handle)  will raise a warning ( {{{Warning: closedir():
 __RESOURCENUMBER__ is not a valid Directory resource in __FILE__ on line
 __LINE__}}} ).
  6. I was able to create ''a lot'' of Stream Resource Handles (on the same
 directory). The memory usage was quite fair (45k RAM on 200k Streams) by
 not closing the handles.
  7. Running the same test while ''closing'' the handles did show some
 difference, slightly more memory was used (about 48k RAM on 200k Streams).
  8. Since 6.) and 7.) did show some differences I developed a better test
 w/o any output until a certain amount of iterations was achieved. You can
 say that there is not much difference between the two but as reported,
 closing directory handles does use more time and more memory but the peak
 usage is the same.

 '''Suggestion'''

 Since directory handles do not look like somehow limited there is no fear
 to run out of those. Since closing does actually does only produce
 overhead and not any benefit, it can be suggested to not close directory
 handles even if this sounds wired.

 '''Testbed'''
 PHP PHP Version 5.2.8; Windows NT 5.1 build 2600; Server API CGI/FastCGI.
 Used xdebug 2.0.0RC4-dev to gather memory and execution time.

-- 
Ticket URL: <http://core.trac.wordpress.org/ticket/11749#comment:1>
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