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         // Return quickly in the most common case
  36         if ( !isset( $wgHooks[$event] ) ) {
  37                 return true;
  38         }
  39
  40         if (!is_array($wgHooks)) {
  41                 throw new MWException("Global hooks array is not an array!\n");
  42                 return false;
  43         }
  44
  45         if (!is_array($wgHooks[$event])) {
  46                 throw new MWException("Hooks array for event '$event' is not an array!\n");
  47                 return false;
  48         }
  49
  50         foreach ($wgHooks[$event] as $index => $hook) {
  51
  52                 $object = null;
  53                 $method = null;
  54                 $func = null;
  55                 $data = null;
  56                 $have_data = false;
  57                 $closure = false;
  58
  59                 /* $hook can be: a function, an object, an array of $function and $data,
  60                  * an array of just a function, an array of object and method, or an
  61                  * array of object, method, and data.
  62                  */
  63
  64                 if ( is_array( $hook ) ) {
  65                         if ( count( $hook ) < 1 ) {
  66                                 throw new MWException("Empty array in hooks for " . $event . "\n");
  67                         } else if ( is_object( $hook[0] ) ) {
  68                                 $object = $wgHooks[$event][$index][0];
  69                                 if ( $object instanceof Closure ) {
  70                                         $closure = true;
  71                                         if ( count( $hook ) > 1 ) {
  72                                                 $data = $hook[1];
  73                                                 $have_data = true;
  74                                         }
  75                                 } else {
  76                                         if ( count( $hook ) < 2 ) {
  77                                                 $method = "on" . $event;
  78                                         } else {
  79                                                 $method = $hook[1];
  80                                                 if ( count( $hook ) > 2 ) {
  81                                                         $data = $hook[2];
  82                                                         $have_data = true;
  83                                                 }
  84                                         }
  85                                 }
  86                         } else if ( is_string( $hook[0] ) ) {
  87                                 $func = $hook[0];
  88                                 if ( count( $hook ) > 1) {
  89                                         $data = $hook[1];
  90                                         $have_data = true;
  91                                 }
  92                         } else {
  93                                 throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
  94                         }
  95                 } else if ( is_string( $hook ) ) { # functions look like strings, too
  96                         $func = $hook;
  97                 } else if ( is_object( $hook ) ) {
  98                         $object = $wgHooks[$event][$index];
  99                         if ( $object instanceof Closure ) {
 100                                 $closure = true;
 101                         } else {
 102                                 $method = "on" . $event;
 103                         }
 104                 } else {
 105                         throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
 106                 }
 107
 108                 /* We put the first data element on, if needed. */
 109
 110                 if ( $have_data ) {
 111                         $hook_args = array_merge(array($data), $args);
 112                 } else {
 113                         $hook_args = $args;
 114                 }
 115
 116                 if ( $closure ) {
 117                         $callback = $object;
 118                         $func = "hook-$event-closure";
 119                 } elseif ( isset( $object ) ) {
 120                         $func = get_class( $object ) . '::' . $method;
 121                         $callback = array( $object, $method );
 122                 } elseif ( false !== ( $pos = strpos( $func, '::' ) ) ) {
 123                         $callback = array( substr( $func, 0, $pos ), substr( $func, $pos + 2 ) );
 124                 } else {
 125                         $callback = $func;
 126                 }
 127
 128                 // Run autoloader (workaround for call_user_func_array bug)
 129                 is_callable( $callback );
 130
 131                 /* Call the hook. */
 132                 wfProfileIn( $func );
 133                 $retval = call_user_func_array( $callback, $hook_args );
 134                 wfProfileOut( $func );
 135
 136                 /* String return is an error; false return means stop processing. */
 137
 138                 if ( is_string( $retval ) ) {
 139                         global $wgOut;
 140                         $wgOut->showFatalError( $retval );
 141                         return false;
 142                 } elseif( $retval === null ) {
 143                         if ( $closure ) {
 144                                 $prettyFunc = "$event closure";
 145                         } elseif( is_array( $callback ) ) {
 146                                 if( is_object( $callback[0] ) ) {
 147                                         $prettyClass = get_class( $callback[0] );
 148                                 } else {
 149                                         $prettyClass = strval( $callback[0] );
 150                                 }
 151                                 $prettyFunc = $prettyClass . '::' . strval( $callback[1] );
 152                         } else {
 153                                 $prettyFunc = strval( $callback );
 154                         }
 155                         throw new MWException( "Detected bug in an extension! " .
 156                                 "Hook $prettyFunc failed to return a value; " .
 157                                 "should return true to continue hook processing or false to abort." );
 158                 } else if ( !$retval ) {
 159                         return false;
 160                 }
 161         }
 162
 163         return true;
 164 }