includes/Hooks.php

   1 <?php
   2 /**
   3  * Hooks.php -- a tool for running hook functions
   4  * Copyright 2004, 2005 Evan Prodromou <evan@wikitravel.org>.
   5  *
   6  *  This program is free software; you can redistribute it and/or modify
   7  *  it under the terms of the GNU General Public License as published by
   8  *  the Free Software Foundation; either version 2 of the License, or
   9  *  (at your option) any later version.
  10  *
  11  *  This program is distributed in the hope that it will be useful,
  12  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *  GNU General Public License for more details.
  15  *
  16  *  You should have received a copy of the GNU General Public License
  17  *  along with this program; if not, write to the Free Software
  18  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * @author Evan Prodromou <evan@wikitravel.org>
  21  * @see hooks.txt
  22  * @file
  23  */
  24
  25
  26 /**
  27  * Because programmers assign to $wgHooks, we need to be very
  28  * careful about its contents. So, there's a lot more error-checking
  29  * in here than would normally be necessary.
  30  */
  31 function wfRunHooks($event, $args = array()) {
  32
  33         global $wgHooks;
  34
  35         if (!is_array($wgHooks)) {
  36                 throw new MWException("Global hooks array is not an array!\n");
  37                 return false;
  38         }
  39
  40         if (!array_key_exists($event, $wgHooks)) {
  41                 return true;
  42         }
  43
  44         if (!is_array($wgHooks[$event])) {
  45                 throw new MWException("Hooks array for event '$event' is not an array!\n");
  46                 return false;
  47         }
  48
  49         foreach ($wgHooks[$event] as $index => $hook) {
  50
  51                 $object = NULL;
  52                 $method = NULL;
  53                 $func = NULL;
  54                 $data = NULL;
  55                 $have_data = false;
  56
  57                 /* $hook can be: a function, an object, an array of $function and $data,
  58                  * an array of just a function, an array of object and method, or an
  59                  * array of object, method, and data.
  60                  */
  61
  62                 if (is_array($hook)) {
  63                         if (count($hook) < 1) {
  64                                 throw new MWException("Empty array in hooks for " . $event . "\n");
  65                         } else if (is_object($hook[0])) {
  66                                 $object = $wgHooks[$event][$index][0];
  67                                 if (count($hook) < 2) {
  68                                         $method = "on" . $event;
  69                                 } else {
  70                                         $method = $hook[1];
  71                                         if (count($hook) > 2) {
  72                                                 $data = $hook[2];
  73                                                 $have_data = true;
  74                                         }
  75                                 }
  76                         } else if (is_string($hook[0])) {
  77                                 $func = $hook[0];
  78                                 if (count($hook) > 1) {
  79                                         $data = $hook[1];
  80                                         $have_data = true;
  81                                 }
  82                         } else {
  83                                 var_dump( $wgHooks );
  84                                 throw new MWException("Unknown datatype in hooks for " . $event . "\n");
  85                         }
  86                 } else if (is_string($hook)) { # functions look like strings, too
  87                         $func = $hook;
  88                 } else if (is_object($hook)) {
  89                         $object = $wgHooks[$event][$index];
  90                         $method = "on" . $event;
  91                 } else {
  92                         throw new MWException("Unknown datatype in hooks for " . $event . "\n");
  93                 }
  94
  95                 /* We put the first data element on, if needed. */
  96
  97                 if ($have_data) {
  98                         $hook_args = array_merge(array($data), $args);
  99                 } else {
 100                         $hook_args = $args;
 101                 }
 102
 103                 if ( isset( $object ) ) {
 104                         $func = get_class( $object ) . '::' . $method;
 105                         $callback = array( $object, $method );
 106                 } elseif ( false !== ( $pos = strpos( $func, '::' ) ) ) {
 107                         $callback = array( substr( $func, 0, $pos ), substr( $func, $pos + 2 ) );
 108                 } else {
 109                         $callback = $func;
 110                 }
 111
 112                 // Run autoloader (workaround for call_user_func_array bug)
 113                 is_callable( $callback );
 114
 115                 /* Call the hook. */
 116                 wfProfileIn( $func );
 117                 $retval = call_user_func_array( $callback, $hook_args );
 118                 wfProfileOut( $func );
 119
 120                 /* String return is an error; false return means stop processing. */
 121
 122                 if (is_string($retval)) {
 123                         global $wgOut;
 124                         $wgOut->showFatalError($retval);
 125                         return false;
 126                 } elseif( $retval === null ) {
 127                         if( is_array( $callback ) ) {
 128                                 if( is_object( $callback[0] ) ) {
 129                                         $prettyClass = get_class( $callback[0] );
 130                                 } else {
 131                                         $prettyClass = strval( $callback[0] );
 132                                 }
 133                                 $prettyFunc = $prettyClass . '::' . strval( $callback[1] );
 134                         } else {
 135                                 $prettyFunc = strval( $callback );
 136                         }
 137                         throw new MWException( "Detected bug in an extension! " .
 138                                 "Hook $prettyFunc failed to return a value; " .
 139                                 "should return true to continue hook processing or false to abort." );
 140                 } else if (!$retval) {
 141                         return false;
 142                 }
 143         }
 144
 145         return true;
 146 }