includes/StubObject.php

   1 <?php
   2
   3 /**
   4  * Class to implement stub globals, which are globals that delay loading the
   5  * their associated module code by deferring initialisation until the first
   6  * method call.
   7  *
   8  * Note on unstub loops:
   9  *
  10  * Unstub loops (infinite recursion) sometimes occur when a constructor calls
  11  * another function, and the other function calls some method of the stub. The
  12  * best way to avoid this is to make constructors as lightweight as possible,
  13  * deferring any initialisation which depends on other modules. As a last
  14  * resort, you can use StubObject::isRealObject() to break the loop, but as a
  15  * general rule, the stub object mechanism should be transparent, and code
  16  * which refers to it should be kept to a minimum.
  17  */
  18 class StubObject {
  19         var $mGlobal, $mClass, $mParams;
  20
  21         /**
  22          * Constructor.
  23          *
  24          * @param String $global name of the global variable.
  25          * @param String $class name of the class of the real object.
  26          * @param Array $param array of parameters to pass to contructor of the real
  27          *                     object.
  28          */
  29         function __construct( $global = null, $class = null, $params = array() ) {
  30                 $this->mGlobal = $global;
  31                 $this->mClass = $class;
  32                 $this->mParams = $params;
  33         }
  34
  35         /**
  36          * Returns a bool value whetever $obj is a stub object. Can be used to break
  37          * a infinite loop when unstubbing an object.
  38          *
  39          * @param Object $obj object to check.
  40          * @return bool true if $obj is not an instance of StubObject class.
  41          */
  42         static function isRealObject( $obj ) {
  43                 return is_object( $obj ) && !($obj instanceof StubObject);
  44         }
  45
  46         /**
  47          * Function called if any function exists with that name in this object.
  48          * It is used to unstub the object. Only used internally, PHP will call
  49          * self::__call() function and that function will call this function.
  50          * This function will also call the function with the same name in the real
  51          * object.
  52          *
  53          * @param String $name name of the function called.
  54          * @param Array $args array of arguments.
  55          */
  56         function _call( $name, $args ) {
  57                 $this->_unstub( $name, 5 );
  58                 return call_user_func_array( array( $GLOBALS[$this->mGlobal], $name ), $args );
  59         }
  60
  61         /**
  62          * Create a new object to replace this stub object.
  63          */
  64         function _newObject() {
  65                 return wfCreateObject( $this->mClass, $this->mParams );
  66         }
  67
  68         /**
  69          * Function called by PHP if no function with that name exists in this
  70          * object.
  71          *
  72          * @param String $name name of the function called
  73          * @param Array $args array of arguments
  74          */
  75         function __call( $name, $args ) {
  76                 return $this->_call( $name, $args );
  77         }
  78
  79         /**
  80          * This function creates a new object of the real class and replace it in
  81          * the global variable.
  82          * This is public, for the convenience of external callers wishing to access
  83          * properties, e.g. eval.php
  84          *
  85          * @param String $name name of the method called in this object.
  86          * @param Integer $level level to go in the stact trace to get the function
  87          *                       who called this function.
  88          */
  89         function _unstub( $name = '_unstub', $level = 2 ) {
  90                 static $recursionLevel = 0;
  91
  92                 if ( !($GLOBALS[$this->mGlobal] instanceof StubObject) )
  93                         return $GLOBALS[$this->mGlobal]; // already unstubbed.
  94
  95                 if ( get_class( $GLOBALS[$this->mGlobal] ) != $this->mClass ) {
  96                         $fname = __METHOD__.'-'.$this->mGlobal;
  97                         wfProfileIn( $fname );
  98                         $caller = wfGetCaller( $level );
  99                         if ( ++$recursionLevel > 2 ) {
 100                                 throw new MWException( "Unstub loop detected on call of \${$this->mGlobal}->$name from $caller\n" );
 101                         }
 102                         wfDebug( "Unstubbing \${$this->mGlobal} on call of \${$this->mGlobal}::$name from $caller\n" );
 103                         $obj = $GLOBALS[$this->mGlobal] = $this->_newObject();
 104                         --$recursionLevel;
 105                         wfProfileOut( $fname );
 106                 }
 107         }
 108 }
 109
 110 /**
 111  * Stub object for the content language of this wiki. This object have to be in
 112  * $wgContLang global.
 113  */
 114 class StubContLang extends StubObject {
 115
 116         function __construct() {
 117                 parent::__construct( 'wgContLang' );
 118         }
 119
 120         function __call( $name, $args ) {
 121                 return $this->_call( $name, $args );
 122         }
 123
 124         function _newObject() {
 125                 global $wgContLanguageCode;
 126                 $obj = Language::factory( $wgContLanguageCode );
 127                 $obj->initEncoding();
 128                 $obj->initContLang();
 129                 return $obj;
 130         }
 131 }
 132
 133 /**
 134  * Stub object for the user language. It depends of the user preferences and
 135  * "uselang" parameter that can be passed to index.php. This object have to be
 136  * in $wgLang global.
 137  */
 138 class StubUserLang extends StubObject {
 139
 140         function __construct() {
 141                 parent::__construct( 'wgLang' );
 142         }
 143
 144         function __call( $name, $args ) {
 145                 return $this->_call( $name, $args );
 146         }
 147
 148         function _newObject() {
 149                 global $wgContLanguageCode, $wgRequest, $wgUser, $wgContLang;
 150                 $code = $wgRequest->getVal( 'uselang', $wgUser->getOption( 'language' ) );
 151                 // BCP 47 - letter case MUST NOT carry meaning
 152                 $code = strtolower( $code );
 153
 154                 # Validate $code
 155                 if( empty( $code ) || !preg_match( '/^[a-z-]+$/', $code ) || ( $code === 'qqq' ) ) {
 156                         wfDebug( "Invalid user language code\n" );
 157                         $code = $wgContLanguageCode;
 158                 }
 159
 160                 if( $code === $wgContLanguageCode ) {
 161                         return $wgContLang;
 162                 } else {
 163                         $obj = Language::factory( $code );
 164                         return $obj;
 165                 }
 166         }
 167 }
 168
 169 /**
 170  * Stub object for the user. The initialisation of the will depend of
 171  * $wgCommandLineMode. If it's true, it will be an anonymous user and if it's
 172  * false, the user will be loaded from credidentails provided by cookies. This
 173  * object have to be in $wgUser global.
 174  */
 175 class StubUser extends StubObject {
 176
 177         function __construct() {
 178                 parent::__construct( 'wgUser' );
 179         }
 180
 181         function __call( $name, $args ) {
 182                 return $this->_call( $name, $args );
 183         }
 184
 185         function _newObject() {
 186                 global $wgCommandLineMode;
 187                 if( $wgCommandLineMode ) {
 188                         $user = new User;
 189                 } else {
 190                         $user = User::newFromSession();
 191                 }
 192                 return $user;
 193         }
 194 }