<?php /** * Delayed loading of global objects. * * 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. * * 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. * http://www.gnu.org/copyleft/gpl.html * * @file */ /** * Class to implement stub globals, which are globals that delay loading the * their associated module code by deferring initialisation until the first * method call. * * Note on reference parameters: * * If the called method takes any parameters by reference, the __call magic * here won't work correctly. The solution is to unstub the object before * calling the method. * * Note on unstub loops: * * Unstub loops (infinite recursion) sometimes occur when a constructor calls * another function, and the other function calls some method of the stub. The * best way to avoid this is to make constructors as lightweight as possible, * deferring any initialisation which depends on other modules. As a last * resort, you can use StubObject::isRealObject() to break the loop, but as a * general rule, the stub object mechanism should be transparent, and code * which refers to it should be kept to a minimum. */ class StubObject { var $mGlobal, $mClass, $mParams; /** * Constructor. * * @param string $global name of the global variable. * @param string $class name of the class of the real object. * @param array $params parameters to pass to constructor of the real * object. */ function __construct( $global = null, $class = null, $params = array() ) { $this->mGlobal = $global; $this->mClass = $class; $this->mParams = $params; } /** * Returns a bool value whenever $obj is a stub object. Can be used to break * a infinite loop when unstubbing an object. * * @param $obj Object to check. * @return Boolean: true if $obj is not an instance of StubObject class. */ static function isRealObject( $obj ) { return is_object( $obj ) && !$obj instanceof StubObject; } /** * Unstubs an object, if it is a stub object. Can be used to break a * infinite loop when unstubbing an object or to avoid reference parameter * breakage. * * @param $obj Object to check. * @return void */ static function unstub( $obj ) { if ( $obj instanceof StubObject ) { $obj->_unstub( 'unstub', 3 ); } } /** * Function called if any function exists with that name in this object. * It is used to unstub the object. Only used internally, PHP will call * self::__call() function and that function will call this function. * This function will also call the function with the same name in the real * object. * * @param string $name name of the function called * @param array $args arguments * @return mixed */ function _call( $name, $args ) { $this->_unstub( $name, 5 ); return call_user_func_array( array( $GLOBALS[$this->mGlobal], $name ), $args ); } /** * Create a new object to replace this stub object. * @return object */ function _newObject() { return MWFunction::newObj( $this->mClass, $this->mParams ); } /** * Function called by PHP if no function with that name exists in this * object. * * @param string $name name of the function called * @param array $args arguments * @return mixed */ function __call( $name, $args ) { return $this->_call( $name, $args ); } /** * This function creates a new object of the real class and replace it in * the global variable. * This is public, for the convenience of external callers wishing to access * properties, e.g. eval.php * * @param string $name name of the method called in this object. * @param $level Integer: level to go in the stack trace to get the function * who called this function. * @throws MWException */ function _unstub( $name = '_unstub', $level = 2 ) { static $recursionLevel = 0; if ( !$GLOBALS[$this->mGlobal] instanceof StubObject ) { return $GLOBALS[$this->mGlobal]; // already unstubbed. } if ( get_class( $GLOBALS[$this->mGlobal] ) != $this->mClass ) { $fname = __METHOD__ . '-' . $this->mGlobal; wfProfileIn( $fname ); $caller = wfGetCaller( $level ); if ( ++$recursionLevel > 2 ) { wfProfileOut( $fname ); throw new MWException( "Unstub loop detected on call of \${$this->mGlobal}->$name from $caller\n" ); } wfDebug( "Unstubbing \${$this->mGlobal} on call of \${$this->mGlobal}::$name from $caller\n" ); $GLOBALS[$this->mGlobal] = $this->_newObject(); --$recursionLevel; wfProfileOut( $fname ); } } } /** * Stub object for the content language of this wiki. This object have to be in * $wgContLang global. * * @deprecated since 1.18 */ class StubContLang extends StubObject { function __construct() { wfDeprecated( __CLASS__, '1.18' ); parent::__construct( 'wgContLang' ); } function __call( $name, $args ) { return $this->_call( $name, $args ); } /** * @return Language */ function _newObject() { global $wgLanguageCode; $obj = Language::factory( $wgLanguageCode ); $obj->initEncoding(); $obj->initContLang(); return $obj; } } /** * Stub object for the user language. It depends of the user preferences and * "uselang" parameter that can be passed to index.php. This object have to be * in $wgLang global. */ class StubUserLang extends StubObject { function __construct() { parent::__construct( 'wgLang' ); } function __call( $name, $args ) { return $this->_call( $name, $args ); } /** * @return Language */ function _newObject() { return RequestContext::getMain()->getLanguage(); } }