added farms to the core

* extracted most farm code into inc/farm.php
* by default farm.php is nowhere included
* added preload.php.dist as an example farm setup
* farm.php can be included in preload.php to activate farming

inc/farm.php

+<?php
+/**
+ * This overwrites DOKU_CONF. Each animal gets its own configuration and data directory.
+ * This can be used together with preload.php. See preload.php.dist for an example setup.
+ *
+ * The farm ($farm) can be any directory and needs to be set.
+ * Animals are direct subdirectories of the farm directory.
+ * There are two different approaches:
+ *  * An .htaccess based setup can use any animal directory name:
+ *    http://example.org/<path_to_farm>/subdir/ will need the subdirectory '$farm/subdir/'.
+ *  * A virtual host based setup needs animal directory names which have to reflect
+ *    the domain name: If an animal resides in http://www.example.org:8080/mysite/test/,
+ *    directories that will match range from '$farm/8080.www.example.org.mysite.test/'
+ *    to a simple '$farm/domain/'.
+ *
+ * @author Anika Henke <anika@selfthinker.org>
+ * @author Michael Klier <chi@chimeric.de>
+ * @author Christopher Smith <chris@jalakai.co.uk>
+ * @author virtual host part of conf_path() based on conf_path() from Drupal.org's /includes/bootstrap.inc
+ *   (see http://cvs.drupal.org/viewvc/drupal/drupal/includes/bootstrap.inc?view=markup)
+ * @license GPL 2 (http://www.gnu.org/licenses/gpl.html)
+*/
+
+// DOKU_FARMDIR needs to be set in preload.php, here the fallback is the same as DOKU_INC (which isn't set yet)
+if(!defined('DOKU_FARMDIR')) define('DOKU_FARMDIR', fullpath(dirname(__FILE__).'/../').'/');
+if(!defined('DOKU_CONF')) define('DOKU_CONF', conf_path(DOKU_FARMDIR));
+if(!defined('DOKU_FARM')) define('DOKU_FARM', false);
+
+
+/**
+ * Find the appropriate configuration directory.
+ *
+ * If the .htaccess based setup is used, the configuration directory can be
+ * any subdirectory of the farm directory.
+ *
+ * Otherwise try finding a matching configuration directory by stripping the
+ * website's hostname from left to right and pathname from right to left. The
+ * first configuration file found will be used; the remaining will ignored.
+ * If no configuration file is found, return the default confdir './conf'.
+ */
+function conf_path($farm) {
+
+    // htaccess based
+    if(isset($_REQUEST['animal'])) {
+        if(!is_dir($farm.'/'.$_REQUEST['animal']))
+            nice_die("Sorry! This Wiki doesn't exist!");
+        if(!defined('DOKU_FARM')) define('DOKU_FARM', 'htaccess');
+        return $farm.'/'.$_REQUEST['animal'].'/conf/';
+    }
+
+    // virtual host based
+    $uri = explode('/', $_SERVER['SCRIPT_NAME'] ? $_SERVER['SCRIPT_NAME'] : $_SERVER['SCRIPT_FILENAME']);
+    $server = explode('.', implode('.', array_reverse(explode(':', rtrim($_SERVER['HTTP_HOST'], '.')))));
+    for ($i = count($uri) - 1; $i > 0; $i--) {
+        for ($j = count($server); $j > 0; $j--) {
+            $dir = implode('.', array_slice($server, -$j)) . implode('.', array_slice($uri, 0, $i));
+            if(is_dir("$farm/$dir/conf/")) {
+                if(!defined('DOKU_FARM')) define('DOKU_FARM', 'virtual');
+                return "$farm/$dir/conf/";
+            }
+        }
+    }
+
+    // default conf directory in farm
+    if(is_dir("$farm/default/conf/")) {
+        if(!defined('DOKU_FARM')) define('DOKU_FARM', 'default');
+        return "$farm/default/conf/";
+    }
+    // farmer
+    return DOKU_INC.'conf/';
+}
+
+/* Use default config files and local animal config files */
+$config_cascade = array(
+    'main' => array(
+        'default'   => array(DOKU_INC.'conf/dokuwiki.php'),
+        'local'     => array(DOKU_CONF.'local.php'),
+        'protected' => array(DOKU_CONF.'local.protected.php'),
+    ),
+    'acronyms'  => array(
+        'default'   => array(DOKU_INC.'conf/acronyms.conf'),
+        'local'     => array(DOKU_CONF.'acronyms.local.conf'),
+    ),
+    'entities'  => array(
+        'default'   => array(DOKU_INC.'conf/entities.conf'),
+        'local'     => array(DOKU_CONF.'entities.local.conf'),
+    ),
+    'interwiki' => array(
+        'default'   => array(DOKU_INC.'conf/interwiki.conf'),
+        'local'     => array(DOKU_CONF.'interwiki.local.conf'),
+    ),
+    'license' => array(
+        'default'   => array(DOKU_INC.'conf/license.php'),
+        'local'     => array(DOKU_CONF.'license.local.php'),
+    ),
+    'mediameta' => array(
+        'default'   => array(DOKU_INC.'conf/mediameta.php'),
+        'local'     => array(DOKU_CONF.'mediameta.local.php'),
+    ),
+    'mime'      => array(
+        'default'   => array(DOKU_INC.'conf/mime.conf'),
+        'local'     => array(DOKU_CONF.'mime.local.conf'),
+    ),
+    'scheme'    => array(
+        'default'   => array(DOKU_INC.'conf/scheme.conf'),
+        'local'     => array(DOKU_CONF.'scheme.local.conf'),
+    ),
+    'smileys'   => array(
+        'default'   => array(DOKU_INC.'conf/smileys.conf'),
+        'local'     => array(DOKU_CONF.'smileys.local.conf'),
+    ),
+    'wordblock' => array(
+        'default'   => array(DOKU_INC.'conf/wordblock.conf'),
+        'local'     => array(DOKU_CONF.'wordblock.local.conf'),
+    ),
+    'acl'       => array(
+        'default'   => DOKU_CONF.'acl.auth.php',
+    ),
+    'plainauth.users' => array(
+        'default'   => DOKU_CONF.'users.auth.php',
+    ),
+    'plugins' => array( // needed since Angua
+        'default'   => array(DOKU_CONF.'plugins.php'),
+        'local'     => array(DOKU_CONF.'plugins.local.php'),
+        'protected' => array(
+            DOKU_INC.'conf/plugins.required.php',
+            DOKU_CONF.'plugins.protected.php',
+        ),
+    ),
+    'userstyle' => array(
+        'default' => DOKU_CONF.'userstyle.css', // 'default' was renamed to 'screen' on 2011-02-26, so will be deprecated in the next version
+        'screen'  => DOKU_CONF.'userstyle.css',
+        'rtl'     => DOKU_CONF.'userrtl.css', // deprecated since version after 2012-04-09
+        'print'   => DOKU_CONF.'userprint.css',
+        'feed'    => DOKU_CONF.'userfeed.css',
+        'all'     => DOKU_CONF.'userall.css',
+    ),
+    'userscript' => array(
+        'default' => DOKU_CONF.'userscript.js'
+    ),
+);

inc/preload.php.dist

+<?php
+/**
+ * This is an example for a farm setup. Simply copy this file to preload.php and
+ * uncomment what you need. See http://dokuwiki.org/farms for more information.
+ * You can also use preload.php for other things than farming, e.g. for moving
+ * local configuration files out of the main ./conf directory.
+ */
+
+// set this to your farm directory
+//if(!defined('DOKU_FARMDIR')) define('DOKU_FARMDIR', '/var/www/farm');
+
+// include this after DOKU_FARMDIR if you want to use farms
+//include(fullpath(dirname(__FILE__)).'/farm.php');
+
+// you can overwrite the $config_cascade to your liking
+//$config_cascade = array(
+//);