<?php
/**
- * Hooks.php -- a tool for running hook functions
+ * A tool for running hook functions.
+ *
* Copyright 2004, 2005 Evan Prodromou <evan@wikitravel.org>.
*
* This program is free software; you can redistribute it and/or modify
*
* @author Evan Prodromou <evan@wikitravel.org>
* @see hooks.txt
+ * @file
*/
/**
+ * Call hook functions defined in $wgHooks
+ *
* Because programmers assign to $wgHooks, we need to be very
* careful about its contents. So, there's a lot more error-checking
* in here than would normally be necessary.
+ *
+ * @param $event String: event name
+ * @param $args Array: parameters passed to hook functions
+ * @return Boolean
*/
-function wfRunHooks($event, $args = null) {
+function wfRunHooks($event, $args = array()) {
global $wgHooks;
+ // Return quickly in the most common case
+ if ( !isset( $wgHooks[$event] ) ) {
+ return true;
+ }
+
if (!is_array($wgHooks)) {
throw new MWException("Global hooks array is not an array!\n");
return false;
}
- if (!array_key_exists($event, $wgHooks)) {
- return true;
- }
-
if (!is_array($wgHooks[$event])) {
throw new MWException("Hooks array for event '$event' is not an array!\n");
return false;
foreach ($wgHooks[$event] as $index => $hook) {
- $object = NULL;
- $method = NULL;
- $func = NULL;
- $data = NULL;
+ $object = null;
+ $method = null;
+ $func = null;
+ $data = null;
$have_data = false;
+ $closure = false;
+ $badhookmsg = false;
/* $hook can be: a function, an object, an array of $function and $data,
* an array of just a function, an array of object and method, or an
* array of object, method, and data.
*/
- if (is_array($hook)) {
- if (count($hook) < 1) {
+ if ( is_array( $hook ) ) {
+ if ( count( $hook ) < 1 ) {
throw new MWException("Empty array in hooks for " . $event . "\n");
- } else if (is_object($hook[0])) {
+ } else if ( is_object( $hook[0] ) ) {
$object = $wgHooks[$event][$index][0];
- if (count($hook) < 2) {
- $method = "on" . $event;
- } else {
- $method = $hook[1];
- if (count($hook) > 2) {
- $data = $hook[2];
+ if ( $object instanceof Closure ) {
+ $closure = true;
+ if ( count( $hook ) > 1 ) {
+ $data = $hook[1];
$have_data = true;
}
+ } else {
+ if ( count( $hook ) < 2 ) {
+ $method = "on" . $event;
+ } else {
+ $method = $hook[1];
+ if ( count( $hook ) > 2 ) {
+ $data = $hook[2];
+ $have_data = true;
+ }
+ }
}
- } else if (is_string($hook[0])) {
+ } else if ( is_string( $hook[0] ) ) {
$func = $hook[0];
- if (count($hook) > 1) {
+ if ( count( $hook ) > 1) {
$data = $hook[1];
$have_data = true;
}
} else {
- var_dump( $wgHooks );
- throw new MWException("Unknown datatype in hooks for " . $event . "\n");
+ throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
}
- } else if (is_string($hook)) { # functions look like strings, too
+ } else if ( is_string( $hook ) ) { # functions look like strings, too
$func = $hook;
- } else if (is_object($hook)) {
+ } else if ( is_object( $hook ) ) {
$object = $wgHooks[$event][$index];
- $method = "on" . $event;
+ if ( $object instanceof Closure ) {
+ $closure = true;
+ } else {
+ $method = "on" . $event;
+ }
} else {
- throw new MWException("Unknown datatype in hooks for " . $event . "\n");
+ throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
}
/* We put the first data element on, if needed. */
- if ($have_data) {
+ if ( $have_data ) {
$hook_args = array_merge(array($data), $args);
} else {
$hook_args = $args;
}
- if ( isset( $object ) ) {
+ if ( $closure ) {
+ $callback = $object;
+ $func = "hook-$event-closure";
+ } elseif ( isset( $object ) ) {
$func = get_class( $object ) . '::' . $method;
$callback = array( $object, $method );
} elseif ( false !== ( $pos = strpos( $func, '::' ) ) ) {
$callback = $func;
}
- /* Call the hook. */
+ // Run autoloader (workaround for call_user_func_array bug)
+ is_callable( $callback );
+
+ /* Call the hook. The documentation of call_user_func_array clearly
+ * states that FALSE is returned on failure. However this is not
+ * case always. In some version of PHP if the function signature
+ * does not match the call signature, PHP will issue an warning:
+ * Param y in x expected to be a reference, value given.
+ *
+ * In that case the call will also return null. The following code
+ * catches that warning and provides better error message. The
+ * function documentation also says that:
+ * In other words, it does not depend on the function signature
+ * whether the parameter is passed by a value or by a reference.
+ * There is also PHP bug http://bugs.php.net/bug.php?id=47554 which
+ * is unsurprisingly marked as bogus. In short handling of failures
+ * with call_user_func_array is a failure, the documentation for that
+ * function is wrong and misleading and PHP developers don't see any
+ * problem here.
+ */
+ $retval = null;
+ set_error_handler( 'hookErrorHandler' );
wfProfileIn( $func );
- $retval = call_user_func_array( $callback, $hook_args );
+ try {
+ $retval = call_user_func_array( $callback, $hook_args );
+ } catch ( MWHookException $e ) {
+ $badhookmsg = $e->getMessage();
+ }
wfProfileOut( $func );
+ restore_error_handler();
/* String return is an error; false return means stop processing. */
-
- if (is_string($retval)) {
+ if ( is_string( $retval ) ) {
global $wgOut;
- $wgOut->showFatalError($retval);
+ $wgOut->showFatalError( $retval );
return false;
} elseif( $retval === null ) {
- if( is_array( $callback ) ) {
+ if ( $closure ) {
+ $prettyFunc = "$event closure";
+ } elseif( is_array( $callback ) ) {
if( is_object( $callback[0] ) ) {
$prettyClass = get_class( $callback[0] );
} else {
} else {
$prettyFunc = strval( $callback );
}
- throw new MWException( "Detected bug in an extension! " .
- "Hook $prettyFunc failed to return a value; " .
- "should return true to continue hook processing or false to abort." );
- } else if (!$retval) {
+ if ( $badhookmsg ) {
+ throw new MWException( "Detected bug in an extension! " .
+ "Hook $prettyFunc has invalid call signature; " . $badhookmsg );
+ } else {
+ throw new MWException( "Detected bug in an extension! " .
+ "Hook $prettyFunc failed to return a value; " .
+ "should return true to continue hook processing or false to abort." );
+ }
+ } else if ( !$retval ) {
return false;
}
}
return true;
}
+function hookErrorHandler( $errno, $errstr ) {
+ if ( strpos( $errstr, 'expected to be a reference, value given' ) !== false ) {
+ throw new MWHookException( $errstr );
+ }
+ return false;
+}
+
+class MWHookException extends MWException {}
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