diff options
Diffstat (limited to 'includes/Hooks.php')
| -rw-r--r-- | includes/Hooks.php | 282 |
1 files changed, 106 insertions, 176 deletions
diff --git a/includes/Hooks.php b/includes/Hooks.php index 8cc7acea..396e360d 100644 --- a/includes/Hooks.php +++ b/includes/Hooks.php @@ -1,4 +1,5 @@ <?php + /** * A tool for running hook functions. * @@ -37,40 +38,43 @@ class MWHookException extends MWException {} */ class Hooks { + /** + * Array of events mapped to an array of callbacks to be run + * when that event is triggered. + */ protected static $handlers = array(); /** - * 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. + * Attach an event handler to a given hook. * - * @since 1.21 - * - * @param string $name the name of the hook to clear. + * @param string $name Name of hook + * @param mixed $callback Callback function to attach * - * @throws MWException if not in testing mode. + * @since 1.18 */ - public static function clear( $name ) { - if ( !defined( 'MW_PHPUNIT_TEST' ) ) { - throw new MWException( 'can not reset hooks in operation.' ); + public static function register( $name, $callback ) { + if ( !isset( self::$handlers[$name] ) ) { + self::$handlers[$name] = array(); } - unset( self::$handlers[$name] ); + self::$handlers[$name][] = $callback; } /** - * Attach an event handler to a given hook + * 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. * - * @since 1.18 + * @param string $name the name of the hook to clear. * - * @param string $name name of hook - * @param $callback Mixed: callback function to attach + * @since 1.21 + * @throws MWException if not in testing mode. */ - public static function register( $name, $callback ) { - if( !isset( self::$handlers[$name] ) ) { - self::$handlers[$name] = array(); + public static function clear( $name ) { + if ( !defined( 'MW_PHPUNIT_TEST' ) ) { + throw new MWException( 'Cannot reset hooks in operation.' ); } - self::$handlers[$name][] = $callback; + unset( self::$handlers[$name] ); } /** @@ -79,216 +83,139 @@ class Hooks { * * @since 1.18 * - * @param string $name name of hook - * @return Boolean: true if the hook has a function registered to it + * @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] ); } /** * 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 * - * @throws MWException - * @throws FatalError - * @param string $name name of the hook + * @since 1.18 * + * @param string $name Name of the hook * @return array */ public static function getHandlers( $name ) { global $wgHooks; - // Return quickly in the most common case - if ( empty( self::$handlers[$name] ) && empty( $wgHooks[$name] ) ) { + if ( !self::isRegistered( $name ) ) { return array(); - } - - if ( !is_array( self::$handlers ) ) { - throw new MWException( "Local hooks array is not an array!\n" ); - } - - if ( !is_array( $wgHooks ) ) { - throw new MWException( "Global hooks array is not an array!\n" ); - } - - if ( empty( Hooks::$handlers[$name] ) ) { - $hooks = $wgHooks[$name]; - } elseif ( empty( $wgHooks[$name] ) ) { - $hooks = Hooks::$handlers[$name]; + } elseif ( !isset( self::$handlers[$name] ) ) { + return $wgHooks[$name]; + } elseif ( !isset( $wgHooks[$name] ) ) { + return self::$handlers[$name]; } else { - // so they are both not empty... - $hooks = array_merge( Hooks::$handlers[$name], $wgHooks[$name] ); + return array_merge( self::$handlers[$name], $wgHooks[$name] ); } - - if ( !is_array( $hooks ) ) { - throw new MWException( "Hooks array for event '$name' is not an array!\n" ); - } - - return $hooks; } /** - * Call hook functions defined in Hooks::register + * Call hook functions defined in Hooks::register and $wgHooks. * - * @param string $event event name - * @param $args Array: parameters passed to hook functions + * For a certain 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. * + * @param string $event Event name + * @param array $args Array of parameters passed to hook functions + * @return bool True if no handler aborted the hook + * + * @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. * @throws MWException * @throws FatalError - * @return Boolean True if no handler aborted the hook */ - public static function run( $event, $args = array() ) { - global $wgHooks; - - // Return quickly in the most common case - if ( empty( self::$handlers[$event] ) && empty( $wgHooks[$event] ) ) { - return true; - } - + public static function run( $event, array $args = array() ) { wfProfileIn( 'hook: ' . $event ); - $hooks = self::getHandlers( $event ); + foreach ( self::getHandlers( $event ) as $hook ) { + // Turn non-array values into an array. (Can't use casting because of objects.) + if ( !is_array( $hook ) ) { + $hook = array( $hook ); + } - foreach ( $hooks as $hook ) { - $object = null; - $method = null; - $func = null; - $data = null; - $have_data = false; - $closure = false; - $badhookmsg = false; + if ( !array_filter( $hook ) ) { + // Either array is empty or it's an array filled with null/false/empty. + continue; + } elseif ( 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 ) ); + } /** * $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 ) { - throw new MWException( 'Empty array in hooks for ' . $event . "\n" ); - } elseif ( is_object( $hook[0] ) ) { - $object = $hook[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; - } - } - } - } elseif ( 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" ); - } - } elseif ( is_string( $hook ) ) { # functions look like strings, too - $func = $hook; - } elseif ( is_object( $hook ) ) { - $object = $hook; - if ( $object instanceof Closure ) { - $closure = true; - } else { - $method = "on" . $event; + if ( $hook[0] instanceof Closure ) { + $func = "hook-$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"; } - } else { - throw new MWException( 'Unknown datatype in hooks for ' . $event . "\n" ); - } - - /* We put the first data element on, if needed. */ - if ( $have_data ) { - $hook_args = array_merge( array( $data ), $args ); - } else { - $hook_args = $args; - } - if ( $closure ) { - $callback = $object; - $func = "hook-$event-closure"; - } elseif ( isset( $object ) ) { $func = get_class( $object ) . '::' . $method; $callback = array( $object, $method ); + } elseif ( is_string( $hook[0] ) ) { + $func = $callback = array_shift( $hook ); } else { - $callback = $func; + throw new MWException( 'Unknown datatype in hooks for ' . $event . "\n" ); } // Run autoloader (workaround for call_user_func_array bug) - is_callable( $callback ); + // and throw error if not callable. + if ( !is_callable( $callback ) ) { + throw new MWException( 'Invalid callback in hooks for ' . $event . "\n" ); + } - /** - * 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. + /* + * Call the hook. The documentation of call_user_func_array says + * false is returned on failure. However, if the function signature + * does not match the call signature, PHP will issue an warning and + * return null instead. The following code catches that warning and + * provides better error message. */ $retval = null; - set_error_handler( 'Hooks::hookErrorHandler' ); + $badhookmsg = null; + $hook_args = array_merge( $hook, $args ); + + // Profile first in case the Profiler causes errors. wfProfileIn( $func ); + set_error_handler( 'Hooks::hookErrorHandler' ); try { $retval = call_user_func_array( $callback, $hook_args ); } catch ( MWHookException $e ) { $badhookmsg = $e->getMessage(); } - wfProfileOut( $func ); restore_error_handler(); + wfProfileOut( $func ); - /* String return is an error; false return means stop processing. */ + // Process the return value. if ( is_string( $retval ) ) { + // String returned means error. throw new FatalError( $retval ); - } 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 ); - } - 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 $prettyFunc failed to return a value; " . - 'should return true to continue hook processing or false to abort.' - ); - } - } elseif ( !$retval ) { + } elseif ( $badhookmsg !== null ) { + // Exception was thrown from Hooks::hookErrorHandler. + throw new MWException( + 'Detected bug in an extension! ' . + "Hook $func has invalid call signature; " . $badhookmsg + ); + } elseif ( $retval === false ) { wfProfileOut( 'hook: ' . $event ); + // False was returned. Stop processing, but no error. return false; } } @@ -298,18 +225,21 @@ class Hooks { } /** + * Handle PHP errors issued inside a hook. Catch errors that have to do with + * a function expecting a reference, and let all others pass through. + * * This REALLY should be protected... but it's public for compatibility * * @since 1.18 * - * @param int $errno Unused - * @param string $errstr error message - * @throws MWHookException - * @return Boolean: false + * @param int $errno Error number (unused) + * @param string $errstr Error message + * @throws MWHookException If the error has to do with the function signature + * @return bool Always returns false */ public static function hookErrorHandler( $errno, $errstr ) { if ( strpos( $errstr, 'expected to be a reference, value given' ) !== false ) { - throw new MWHookException( $errstr ); + throw new MWHookException( $errstr, $errno ); } return false; } |