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                 $closure = false;
  57
  58                 /* $hook can be: a function, an object, an array of $function and $data,
  59                  * an array of just a function, an array of object and method, or an
  60                  * array of object, method, and data.
  61                  */
  62
  63                 if ( is_array( $hook ) ) {
  64                         if ( count( $hook ) < 1 ) {
  65                                 throw new MWException("Empty array in hooks for " . $event . "\n");
  66                         } else if ( is_object( $hook[0] ) ) {
  67                                 $object = $wgHooks[$event][$index][0];
  68                                 if ( $object instanceof Closure ) {
  69                                         $closure = true;
  70                                         if ( count( $hook ) > 1 ) {
  71                                                 $data = $hook[1];
  72                                                 $have_data = true;
  73                                         }
  74                                 } else {
  75                                         if ( count( $hook ) < 2 ) {
  76                                                 $method = "on" . $event;
  77                                         } else {
  78                                                 $method = $hook[1];
  79                                                 if ( count( $hook ) > 2 ) {
  80                                                         $data = $hook[2];
  81                                                         $have_data = true;
  82                                                 }
  83                                         }
  84                                 }
  85                         } else if ( is_string( $hook[0] ) ) {
  86                                 $func = $hook[0];
  87                                 if ( count( $hook ) > 1) {
  88                                         $data = $hook[1];
  89                                         $have_data = true;
  90                                 }
  91                         } else {
  92                                 throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
  93                         }
  94                 } else if ( is_string( $hook ) ) { # functions look like strings, too
  95                         $func = $hook;
  96                 } else if ( is_object( $hook ) ) {
  97                         $object = $wgHooks[$event][$index];
  98                         if ( $object instanceof Closure ) {
  99                                 $closure = true;
 100                         } else {
 101                                 $method = "on" . $event;
 102                         }
 103                 } else {
 104                         throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
 105                 }
 106
 107                 /* We put the first data element on, if needed. */
 108
 109                 if ( $have_data ) {
 110                         $hook_args = array_merge(array($data), $args);
 111                 } else {
 112                         $hook_args = $args;
 113                 }
 114
 115                 if ( $closure ) {
 116                         $callback = $object;
 117                         $func = "hook-$event-closure";
 118                 } elseif ( isset( $object ) ) {
 119                         $func = get_class( $object ) . '::' . $method;
 120                         $callback = array( $object, $method );
 121                 } elseif ( false !== ( $pos = strpos( $func, '::' ) ) ) {
 122                         $callback = array( substr( $func, 0, $pos ), substr( $func, $pos + 2 ) );
 123                 } else {
 124                         $callback = $func;
 125                 }
 126
 127                 // Run autoloader (workaround for call_user_func_array bug)
 128                 is_callable( $callback );
 129
 130                 /* Call the hook. */
 131                 wfProfileIn( $func );
 132                 $retval = call_user_func_array( $callback, $hook_args );
 133                 wfProfileOut( $func );
 134
 135                 /* String return is an error; false return means stop processing. */
 136
 137                 if ( is_string( $retval ) ) {
 138                         global $wgOut;
 139                         $wgOut->showFatalError( $retval );
 140                         return false;
 141                 } elseif( $retval === null ) {
 142                         if ( $closure ) {
 143                                 $prettyFunc = "$event closure";
 144                         } elseif( is_array( $callback ) ) {
 145                                 if( is_object( $callback[0] ) ) {
 146                                         $prettyClass = get_class( $callback[0] );
 147                                 } else {
 148                                         $prettyClass = strval( $callback[0] );
 149                                 }
 150                                 $prettyFunc = $prettyClass . '::' . strval( $callback[1] );
 151                         } else {
 152                                 $prettyFunc = strval( $callback );
 153                         }
 154                         throw new MWException( "Detected bug in an extension! " .
 155                                 "Hook $prettyFunc failed to return a value; " .
 156                                 "should return true to continue hook processing or false to abort." );
 157                 } else if ( !$retval ) {
 158                         return false;
 159                 }
 160         }
 161
 162         return true;
 163 }