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Re: How expensive is glob'ing a dir and including all the files?

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Jerry Stuckle <jstucklex@attglobal.net> writes:

> On 9/15/2012 2:08 AM, Anders Wegge Keller wrote:
> > "J. Frank Parnell" <juglesh@gmail.com> writes:
> >
> >> So, my question is, am I saving a significant amount of ram/cpu/time
> >> by keeping this cache of filenames or should I just glob the dir and
> >> include what's in there everytime?
> >
> >   You may want to consider autoloading classes as needed. See
> > http://php.net/manual/en/language.oop5.autoload.php
> >
> >   This approach is of course dependent on using PHP5 *and* having an
> > OO design.
> >
> 
> Additionally, you're never sure which module you got. 

 Speaking from experience?

> All kinds of hard-to-diagnose things can happen when someone uploads
> a module of the same name but earlier in the search path.

 You let "someone" muck around with your code? Are you hosting at
GoDaddy or something like that?

>  You'll be trying to debug one module while the system is using an
> entirely different module.

 Only if you haven't got a clue...
 
> Plus the extra overhead of searching for the module, of course.

 Surely, you are jesting. Or should I ask "Once unwitting, twice shy"?

> This is not a feature I recommend.  It can cause many problems, and
> good programming techniques render it pretty much unnecessary.

 I don't expect you to recognize a metric ton of clue, landing on your
head, but for the record let me tell the rest of the audience what the
self-proclaimed king of c.l.p is not smart enough to fiure out.

 Wait for it...

 Wait a bit more ...


 The autoloader can be overridden by whatever code you care to call
when there is a request for an unknown class <rimshot />

[Simplified code ahead]

{classloader.php}

global $clClassMap;

$clClassMap = array(
		    /* Interfaces */
		    'iArticle' => 'classes/articleinterface.php',

		    /* Base classes */
		    'Page' => 'classes/pageobj.php',
		    'Request' => 'classes/request.php',

                    ... <<The rest of whatever classes defined>>

		    );


class AutoLoader {
  static function autoload ($classname) {
    global $clClassMap;

    $filename = false;

    if ( isset ( $clClassMap[$classname] ) ) {
      $filename=$clClassMap[$classname]
      require("${ABSROOT}/${filename}");
    } else {
      return false; /* And throw an error. */
    }
}

if ( function_exists ( 'spl_autoload_register' ) ) {
  spl_autoload_register ( array('AutoLoader', 'autoload') );
} else {
  function __autoload( $class ) {
    AutoLoader::autoload( $class );
  }
  
  ini_set( 'unserialize_callback_func', '__autoload' );
}

{END classloader.php}

 Everywhere else, require classloader.php, and use whatever classe you
want to. In case you forget to add them to $clClassMap, even Jerry
Stuckle should be smart enough to get what the error means. At least
after a few false starts. Also note that there is no noticable
overhead looking up an entry in a already-loaded array, compared to
the amortized overhead of the Stuckle-approved method of including and
parsing everything that has a remote chance of being relevant.

 There might be a typo or two in the preceeding code. After all, it's
a simplified example. But I expect the majority of this group to be
able to work out the syntax errors. If not, please ask for
clarification.

-- 
/Wegge

Leder efter redundant peering af dk.*,linux.debian.*

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Thread

How expensive is glob'ing a dir and including all the files? "J. Frank Parnell" <juglesh@gmail.com> - 2012-09-14 12:35 -0700
  Re: How expensive is glob'ing a dir and including all the files? Eli the Bearded <*@eli.users.panix.com> - 2012-09-14 19:41 +0000
    Re: How expensive is glob'ing a dir and including all the files? "J. Frank Parnell" <juglesh@gmail.com> - 2012-09-14 15:24 -0700
      Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-14 19:24 -0400
        Re: How expensive is glob'ing a dir and including all the files? Michael Fesser <netizen@gmx.de> - 2012-09-15 01:43 +0200
          Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-14 21:45 -0400
            Re: How expensive is glob'ing a dir and including all the files? "J. Frank Parnell" <juglesh@gmail.com> - 2012-09-16 10:50 -0700
              Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-16 17:45 -0400
                Re: How expensive is glob'ing a dir and including all the files? "J. Frank Parnell" <juglesh@gmail.com> - 2012-09-16 16:00 -0700
                Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-16 20:17 -0400
  Re: How expensive is glob'ing a dir and including all the files? Salvatore <sal@yojimbo.hack.invalid> - 2012-09-14 19:44 +0000
  Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-15 08:08 +0200
    Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 09:14 -0400
      Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-15 23:41 +0200
        Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 18:06 -0400
          Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-16 00:10 +0200
            Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 18:21 -0400
              Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-16 00:39 +0200
                Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 18:45 -0400
                Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-16 00:59 +0200
                Re: How expensive is glob'ing a dir and including all the files? The Natural Philosopher <tnp@invalid.invalid> - 2012-09-16 00:09 +0100
                Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 19:19 -0400
                Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-15 19:27 -0400
            Re: How expensive is glob'ing a dir and including all the files? The Natural Philosopher <tnp@invalid.invalid> - 2012-09-15 23:38 +0100
        Re: How expensive is glob'ing a dir and including all the files? "Peter H. Coffin" <hellsop@ninehells.com> - 2012-09-16 09:37 -0500
          Re: How expensive is glob'ing a dir and including all the files? Anders Wegge Keller <wegge@wegge.dk> - 2012-09-16 17:32 +0200
            Re: How expensive is glob'ing a dir and including all the files? Jerry Stuckle <jstucklex@attglobal.net> - 2012-09-16 17:46 -0400

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