<?php
+
/**
* 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
- * it under the terms of the GNU General Public License as published by
- * the Free Software Foundation; either version 2 of the License, or
- * (at your option) any later version.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
*
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
- * GNU General Public License for more details.
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
*
* @author Evan Prodromou <evan@wikitravel.org>
* @see hooks.txt
* @file
*/
-
/**
- * Call hook functions defined in $wgHooks
+ * Hooks class.
*
- * 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.
+ * Used to supersede $wgHooks, because globals are EVIL.
*
- * @param $event String: event name
- * @param $args Array: parameters passed to hook functions
- * @return Boolean
+ * @since 1.18
*/
-function wfRunHooks($event, $args = array()) {
-
- global $wgHooks;
+class Hooks {
+ /**
+ * Array of events mapped to an array of callbacks to be run
+ * when that event is triggered.
+ */
+ protected static $handlers = [];
+
+ /**
+ * Attach an event handler to a given hook.
+ *
+ * @param string $name Name of hook
+ * @param callable $callback Callback function to attach
+ *
+ * @since 1.18
+ */
+ public static function register( $name, $callback ) {
+ if ( !isset( self::$handlers[$name] ) ) {
+ self::$handlers[$name] = [];
+ }
- // Return quickly in the most common case
- if ( !isset( $wgHooks[$event] ) ) {
- return true;
+ self::$handlers[$name][] = $callback;
}
- if (!is_array($wgHooks)) {
- throw new MWException("Global hooks array is not an array!\n");
+ /**
+ * Clears hooks registered via Hooks::register(). Does not touch $wgHooks.
+ * This is intended for use while testing and will fail if MW_PHPUNIT_TEST is not defined.
+ *
+ * @param string $name The name of the hook to clear.
+ *
+ * @since 1.21
+ * @throws MWException If not in testing mode.
+ */
+ public static function clear( $name ) {
+ if ( !defined( 'MW_PHPUNIT_TEST' ) && !defined( 'MW_PARSER_TEST' ) ) {
+ throw new MWException( 'Cannot reset hooks in operation.' );
+ }
+
+ unset( self::$handlers[$name] );
}
- if (!is_array($wgHooks[$event])) {
- throw new MWException("Hooks array for event '$event' is not an array!\n");
+ /**
+ * Returns true if a hook has a function registered to it.
+ * The function may have been registered either via Hooks::register or in $wgHooks.
+ *
+ * @since 1.18
+ *
+ * @param string $name Name of hook
+ * @return bool True if the hook has a function registered to it
+ */
+ public static function isRegistered( $name ) {
+ global $wgHooks;
+ return !empty( $wgHooks[$name] ) || !empty( self::$handlers[$name] );
}
- foreach ($wgHooks[$event] as $index => $hook) {
+ /**
+ * Returns an array of all the event functions attached to a hook
+ * This combines functions registered via Hooks::register and with $wgHooks.
+ *
+ * @since 1.18
+ *
+ * @param string $name Name of the hook
+ * @return array
+ */
+ public static function getHandlers( $name ) {
+ global $wgHooks;
+
+ if ( !self::isRegistered( $name ) ) {
+ return [];
+ } elseif ( !isset( self::$handlers[$name] ) ) {
+ return $wgHooks[$name];
+ } elseif ( !isset( $wgHooks[$name] ) ) {
+ return self::$handlers[$name];
+ } else {
+ return array_merge( self::$handlers[$name], $wgHooks[$name] );
+ }
+ }
- $object = null;
- $method = null;
- $func = null;
- $data = null;
- $have_data = false;
- $closure = false;
- $badhookmsg = false;
+ /**
+ * @param string $event Event name
+ * @param array|callable $hook
+ * @param array $args Array of parameters passed to hook functions
+ * @param string|null $deprecatedVersion [optional]
+ * @param string &$fname [optional] Readable name of hook [returned]
+ * @return null|string|bool
+ */
+ private static function callHook( $event, $hook, array $args, $deprecatedVersion = null,
+ &$fname = null
+ ) {
+ // Turn non-array values into an array. (Can't use casting because of objects.)
+ if ( !is_array( $hook ) ) {
+ $hook = [ $hook ];
+ }
- /* $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 ( !array_filter( $hook ) ) {
+ // Either array is empty or it's an array filled with null/false/empty.
+ return null;
+ }
- if ( is_array( $hook ) ) {
- if ( count( $hook ) < 1 ) {
- throw new MWException("Empty array in hooks for " . $event . "\n");
- } else if ( is_object( $hook[0] ) ) {
- $object = $wgHooks[$event][$index][0];
- 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] ) ) {
- $func = $hook[0];
- if ( count( $hook ) > 1) {
- $data = $hook[1];
- $have_data = true;
- }
- } else {
- throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
- }
- } else if ( is_string( $hook ) ) { # functions look like strings, too
- $func = $hook;
- } else if ( is_object( $hook ) ) {
- $object = $wgHooks[$event][$index];
- if ( $object instanceof Closure ) {
- $closure = true;
- } else {
- $method = "on" . $event;
- }
- } else {
- throw new MWException( "Unknown datatype in hooks for " . $event . "\n" );
+ if ( is_array( $hook[0] ) ) {
+ // First element is an array, meaning the developer intended
+ // the first element to be a callback. Merge it in so that
+ // processing can be uniform.
+ $hook = array_merge( $hook[0], array_slice( $hook, 1 ) );
}
- /* We put the first data element on, if needed. */
+ /**
+ * $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 ( $hook[0] instanceof Closure ) {
+ $fname = "hook-$event-closure";
+ $callback = array_shift( $hook );
+ } elseif ( is_object( $hook[0] ) ) {
+ $object = array_shift( $hook );
+ $method = array_shift( $hook );
+
+ // If no method was specified, default to on$event.
+ if ( $method === null ) {
+ $method = "on$event";
+ }
- if ( $have_data ) {
- $hook_args = array_merge(array($data), $args);
+ $fname = get_class( $object ) . '::' . $method;
+ $callback = [ $object, $method ];
+ } elseif ( is_string( $hook[0] ) ) {
+ $fname = $callback = array_shift( $hook );
} else {
- $hook_args = $args;
+ throw new MWException( 'Unknown datatype in hooks for ' . $event . "\n" );
}
- 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 = array( substr( $func, 0, $pos ), substr( $func, $pos + 2 ) );
- } else {
- $callback = $func;
+ // Run autoloader (workaround for call_user_func_array bug)
+ // and throw error if not callable.
+ if ( !is_callable( $callback ) ) {
+ throw new MWException( 'Invalid callback ' . $fname . ' in hooks for ' . $event . "\n" );
}
- // 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 );
- try {
- $retval = call_user_func_array( $callback, $hook_args );
- } catch ( MWHookException $e ) {
- $badhookmsg = $e->getMessage();
+ // mark hook as deprecated, if deprecation version is specified
+ if ( $deprecatedVersion !== null ) {
+ wfDeprecated( "$event hook (used in $fname)", $deprecatedVersion );
}
- wfProfileOut( $func );
- restore_error_handler();
-
- /* String return is an error; false return means stop processing. */
- if ( is_string( $retval ) ) {
- global $wgOut;
- $wgOut->showFatalError( $retval );
- return false;
- } elseif( $retval === null ) {
- if ( $closure ) {
- $prettyFunc = "$event closure";
- } elseif( is_array( $callback ) ) {
- if( is_object( $callback[0] ) ) {
- $prettyClass = get_class( $callback[0] );
- } else {
- $prettyClass = strval( $callback[0] );
- }
- $prettyFunc = $prettyClass . '::' . strval( $callback[1] );
- } else {
- $prettyFunc = strval( $callback );
+
+ // Call the hook.
+ $hook_args = array_merge( $hook, $args );
+ return call_user_func_array( $callback, $hook_args );
+ }
+
+ /**
+ * Call hook functions defined in Hooks::register and $wgHooks.
+ *
+ * For the given hook event, fetch the array of hook events and
+ * process them. Determine the proper callback for each hook and
+ * then call the actual hook using the appropriate arguments.
+ * Finally, process the return value and return/throw accordingly.
+ *
+ * For hook event that are not abortable through a handler's return value,
+ * use runWithoutAbort() instead.
+ *
+ * @param string $event Event name
+ * @param array $args Array of parameters passed to hook functions
+ * @param string|null $deprecatedVersion [optional] Mark hook as deprecated with version number
+ * @return bool True if no handler aborted the hook
+ *
+ * @throws Exception
+ * @throws FatalError
+ * @throws MWException
+ * @since 1.22 A hook function is not required to return a value for
+ * processing to continue. Not returning a value (or explicitly
+ * returning null) is equivalent to returning true.
+ */
+ public static function run( $event, array $args = [], $deprecatedVersion = null ) {
+ foreach ( self::getHandlers( $event ) as $hook ) {
+ $retval = self::callHook( $event, $hook, $args, $deprecatedVersion );
+ if ( $retval === null ) {
+ continue;
}
- 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." );
+
+ // Process the return value.
+ if ( is_string( $retval ) ) {
+ // String returned means error.
+ throw new FatalError( $retval );
+ } elseif ( $retval === false ) {
+ // False was returned. Stop processing, but no error.
+ return false;
}
- } else if ( !$retval ) {
- return false;
}
- }
- return true;
-}
+ return true;
+ }
-function hookErrorHandler( $errno, $errstr ) {
- if ( strpos( $errstr, 'expected to be a reference, value given' ) !== false ) {
- throw new MWHookException( $errstr );
+ /**
+ * Call hook functions defined in Hooks::register and $wgHooks.
+ *
+ * @param string $event Event name
+ * @param array $args Array of parameters passed to hook functions
+ * @param string|null $deprecatedVersion [optional] Mark hook as deprecated with version number
+ * @return bool Always true
+ * @throws MWException If a callback is invalid, unknown
+ * @throws UnexpectedValueException If a callback returns an abort value.
+ * @since 1.30
+ */
+ public static function runWithoutAbort( $event, array $args = [], $deprecatedVersion = null ) {
+ foreach ( self::getHandlers( $event ) as $hook ) {
+ $fname = null;
+ $retval = self::callHook( $event, $hook, $args, $deprecatedVersion, $fname );
+ if ( $retval !== null && $retval !== true ) {
+ throw new UnexpectedValueException( "Invalid return from $fname for unabortable $event." );
+ }
+ }
+ return true;
}
- return false;
}
-
-class MWHookException extends MWException {}
\ No newline at end of file
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