silverstripe-framework/core/Object.php

<?php
/**
 * Base object that all others should inherit from.
 * This object provides a number of helper methods that patch over PHP's deficiencies.
 */

class Object {
	/**
	 * This DataObjects extensions, eg Versioned.
	 * @var array
	 */
	protected $extension_instances = array();

	/**
	 * Extensions to be used on this object. An array of extension names
	 * and parameters eg:
	 * 
	 * 	static $extensions = array(
	 * 		"Hierarchy",
	 * 		"Versioned('Stage', 'Live')",
	 * 	);
	 * 
	 * @var array
	 */
	public static $extensions = null;

	protected static $extraStatics = array();
	protected static $classConstructed = array();

	protected static $extraMethods = array();
	protected static $builtInMethods = array();
    
    /**
    * Use the class in the value instead of the class in the key
    */
    private static $custom_classes = array();
	private static $strong_classes = array();
    


	/**
	 * This function allows you to overload class creation methods, so certain classes are 
	 * always created correctly over your system. 
	 * 
	 * @param oldClass = the old classname you want to replace with.
	 * @param customClass = the new Classname you wish to replace the old class with.
	 * @param strong - If you want to force a replacement of a class then we use a different array
	 * e.g for use in singleton classes.
	 */
    public static function useCustomClass( $oldClass, $customClass,$strong = false ) {
        if($strong){
        	self::$strong_classes[$oldClass] = $customClass;
		}else{
			self::$custom_classes[$oldClass] = $customClass;
		}
    }
    
    public static function getCustomClass( $oldClass ) {
    	if( array_key_exists($oldClass, self::$custom_classes) )
    		return self::$custom_classes[$oldClass];
    	else{
     		return $oldClass;
		}
    }
    
	/**
	 * Create allows us to override the standard classes of sapphire with our own custom classes.
	 * create will load strong classes firstly for singleton level and database interaction, otherwise will 
	 * use the fallback custom classes. 
	 * To set a strong custom class to overide an object at for say singleton use, use the syntax 
	 *  Object::useCustomClass('Datetime','SSDatetime',true);
	 * @param className - The classname you want to create
	 * @param args -  Up to 9 arguments you wish to pass on to the new class
	 */
    public static function create( $className, $arg0 = null, $arg1 = null, $arg2 = null, $arg3 = null, $arg4 = null, $arg5 = null, $arg6 = null, $arg7 = null, $arg8 = null ) {
		
		$useStrongClassName =  isset(self::$strong_classes[$className]);
		$useClassName = isset(self::$custom_classes[$className]);
		
		if($useStrongClassName){
			$classToCreate = self::$strong_classes[$className];
		}elseif($useClassName){
			$classToCreate = self::$custom_classes[$className];	
		}
		
		$hasStrong = isset(self::$strong_classes[$className]) && class_exists(self::$strong_classes[$className]);
		$hasNormal = isset(self::$custom_classes[$className]) && class_exists(self::$custom_classes[$className]);
		
		if( !isset($classToCreate) || (!$hasStrong && !$hasNormal)){
		  	 $classToCreate = $className;
		}
        return new $classToCreate( $arg0, $arg1, $arg2, $arg3, $arg4, $arg5, $arg6, $arg7, $arg8 );   
    }
	
	
	/**
	 * Strong_create is a function to enforce a certain class replacement
	 * e.g Php5.2's latest introduction of a namespace conflict means we have to replace
	 * all instances of Datetime with SSdatetime.
	 * this allows us to seperate those, and sapphires classes
	 * @param className -  The class you wish to create.
	 * @param args - pass up to 8 arguments to the created class.
	 */
	public static function strong_create( $className, $arg0 = null, $arg1 = null, $arg2 = null, $arg3 = null, $arg4 = null, $arg5 = null, $arg6 = null, $arg7 = null, $arg8 = null ) {
		$useStrongClassName =  isset(self::$strong_classes[$className]);
		if($useStrongClassName){
			$classToCreate = self::$strong_classes[$className];
		}
		if( !isset($classToCreate) || !class_exists( self::$strong_classes[$className])){
		  	 $classToCreate = $className;
		}
        return new $classToCreate( $arg0, $arg1, $arg2, $arg3, $arg4, $arg5, $arg6, $arg7, $arg8 ); 
	}
	
	
	function __construct() {
		$this->class = get_class($this);	

		// Set up the extensions
		if($extensions = $this->stat('extensions')) {
			foreach($extensions as $extension) {
				$instance = eval("return new $extension;");
				$instance->setOwner($this);
				$this->extension_instances[$instance->class] = $instance;
			}
		}

		if(!isset(Object::$classConstructed[$this->class])) {
			$this->defineMethods();
			Object::$classConstructed[$this->class] = true;
		}
	}
	
	
	/**
	 * Returns true if this object "exists", i.e., has a sensible value.
	 * Overload this in subclasses.
	 * For example, an empty DataObject record could return false.
	 */
	public function exists() {
		return true;
	}
	
	/**
	 * Returns true if the given method exists.
	 */
	public function hasMethod($methodName) {
		if(!isset($this->class)) $this->class = get_class($this);
		if(!isset(Object::$builtInMethods['_set'][$this->class])) $this->buildMethodList();

		if(isset(Object::$builtInMethods[$this->class][$methodName])) return true;
		if(isset(Object::$extraMethods[$this->class][$methodName])) return true;
		return false;
	}
	
	/**
	 * Calls a method.
	 * Extra methods can be hooked to a class using
	 */
	public function __call($methodName, $args) {
		if(isset(Object::$extraMethods[$this->class][$methodName])) {
			$config = Object::$extraMethods[$this->class][$methodName];
			if(isset($config['parameterName'])) {
				if(isset($config['arrayIndex'])) $obj = $this->{$config['parameterName']}[$config['arrayIndex']];
				else $obj = $this->{$config['parameterName']};
				
				if($obj) {
					return call_user_func_array(array(&$obj, $methodName), $args);
				} else {
					if($this->destroyed) user_error("Attempted to call $methodName on destroyed '$this->class' object", E_USER_ERROR);
					else user_error("'$this->class' object doesn't have a parameter $config[parameterName]($config[arrayIndex]) to pass control to.  Perhaps this object has been mistakenly destroyed?", E_USER_WARNING);
				}

			} else if(isset($config['wrap'])) {
				array_unshift($args, $methodName);
				return call_user_func_array(array(&$this, $config['wrap']), $args);
	
			} else if(isset($config['function'])) {
				$function = $config['function'];
				return $function($this, $args);
				
			} else if($config['function_str']) {
				$function = Object::$extraMethods[$this->class][$methodName]['function'] = create_function('$obj, $args', $config['function_str']);
				return $function($this, $args);
	
			} else {
				user_error("Object::__call() Method '$methodName' in class '$this->class' an invalid format: " . var_export(Object::$extraMethods[$this->class][$methodName],true), E_USER_ERROR);
			}
		} else {
			user_error("Object::__call() Method '$methodName' not found in class '$this->class'", E_USER_ERROR);
		}
	}

	/**
	 * Add the all methods from a given parameter to this object.
	 * This is used for extensions.
	 * @param parameterName The name of the parameter.  This parameter must be instanciated with an item of the correct class.
	 * @param arrayIndex If parameterName is an array, this can be an index.  If null, we'll assume the value is all that is needed.
	 */
	protected function addMethodsFrom($parameterName, $arrayIndex = null) {
		$obj = isset($arrayIndex) ? $this->{$parameterName}[$arrayIndex] : $this->$parameterName;
		if(!$obj) user_error("Object::addMethodsFrom: $parameterName/$arrayIndex", E_USER_ERROR);
		// Hack to fix Fatal error: Call to undefined method stdClass::allMethodNames()
		if(method_exists($obj, 'allMethodNames')) {
			$methodNames = $obj->allMethodNames(true);
			foreach($methodNames as $methodName) {
				Object::$extraMethods[$this->class][$methodName] = array("parameterName" => $parameterName, "arrayIndex" => $arrayIndex);
			}
		}
	}
	
	/**
	 * Add a 'wrapper method'.
	 * For example, Thumbnail($arg, $arg) can be defined to call generateImage("Thumbnail", $arg, $arg)
	 */
	protected function addWrapperMethod($methodName, $wrapperMethod) {
		Object::$extraMethods[$this->class][$methodName] = array("wrap" => $wrapperMethod);
	}
	
	/**
	 * Create a new method
	 * @param methodName The name of the method
	 * @param methodCode The PHP code of the method, in a string.  Arguments will be contained
	 * in an array called $args.  The object will be $obj, not $this.  You won't be able to access
	 * any protected methods; the method is actually contained in an external function.
	 */
	protected function createMethod($methodName, $methodCode) {
		Object::$extraMethods[$this->class][$methodName] = array("function_str" => $methodCode);
	}

	/**
	 * Return the names of all the methods on this object.
	 * param includeCustom If set to true, then return custom methods too.
	 */
	function allMethodNames($includeCustom = false) {
		if(!$this->class) $this->class = get_class($this);
		
		if(!isset(Object::$builtInMethods['_set'][$this->class])) $this->buildMethodList();

		if($includeCustom && isset(Object::$extraMethods[$this->class])) {
			return array_merge(Object::$builtInMethods[$this->class], array_keys(Object::$extraMethods[$this->class]));
		} else {
			return Object::$builtInMethods[$this->class];
		}
	}
	
	function buildMethodList() {
		if(!$this->class) $this->class = get_class($this);
		$reflection = new ReflectionClass($this->class);
		
		$methods = $reflection->getMethods();
		foreach($methods as $method) {
			$name = $method->getName();
			$methodNames[$name] = $name;
		}
		Object::$builtInMethods[$this->class] = $methodNames;
		Object::$builtInMethods['_set'][$this->class] = true	;
	}
	
	/**
	 * This constructor will be called the first time an object of this class is created.
	 * You can overload it with methods for setting up the class - for example, extra methods.
	 */
	protected function defineMethods() {
		if($this->extension_instances) foreach($this->extension_instances as $i => $instance) {
			$this->addMethodsFrom('extension_instances', $i);
		}

		if(isset($_REQUEST['debugmethods']) && isset(Object::$builtInMethods[$this->class])) {
			echo "<h2>Methods defined for $this->class</h2>";
			foreach(Object::$builtInMethods[$this->class] as $name => $info) {
				echo "<li>$name";
			}
		}
	}
	
	/**
	 * This method lets us extend a built-in class by adding static variables to it
	 */
	static function addStaticVars($class, $statics) {
		if (empty(Object::$extraStatics[$class])) {
			Object::$extraStatics[$class] = (array)$statics;
		} else {
			$ar1 = (array)Object::$extraStatics[$class]; // First Array To Merge
			$ar2 = (array)$statics; // Second Array To Merge
			Object::$extraStatics[$class] = array_merge_recursive($ar1, $ar2);
		}
	}
	
	function parentClass() {
		return get_parent_class($this);
	}
	function is_a($class) {
		return is_a($this, $class);
	}
	
	/**
	 * Set an uninherited static variable
	 */
	function set_uninherited($name, $val) {
		return Object::$uninherited_statics[$this->class][$name] = $val;
	}
	/**
	 * Get an uninherited static variable
	 */
	function uninherited($name, $builtIn = false) {
		// Copy a built-in value into our own array cache.  PHP's static variable support is shit.
		if($builtIn) {
			$val = $this->stat($name);
			$val2 = eval("return " . get_parent_class($this) . "::\$$name;");
			return ($val != $val2) ? $val : null;
		}

		return isset(Object::$uninherited_statics[$this->class][$name]) ? Object::$uninherited_statics[$this->class][$name] : null;
	}
	
	
	protected static $statics = array();
	protected static $static_cached = array();
	
	/**
	 * Get a static variable
	 */
	function stat($name) {
		if(!$this->class) $this->class = get_class($this);
		
		if(!isset(Object::$static_cached[$this->class][$name])) {
			$classes = ClassInfo::ancestry($this->class);
			foreach($classes as $class) {
				if(isset(Object::$extraStatics[$class][$name])) {
					$extra = Object::$extraStatics[$class][$name];
					if(!is_array($extra)) return $extra;
					break;
				}
			}
			$stat = eval("return {$this->class}::\$$name;");
			Object::$statics[$this->class][$name] = isset($extra) ? array_merge($extra, (array)$stat) : $stat;
			Object::$static_cached[$this->class][$name] = true;
		}

		return Object::$statics[$this->class][$name];
	}
	/**
	 * Set a static variable
	 */
	function set_stat($name, $val) {
		Object::$statics[$this->class][$name] = $val;
		Object::$static_cached[$this->class][$name] = true;
	}

	public $class;
	private static $uninherited_statics = array();
	
	public function __toString() {
		return $this->class;
	}
	
	
	/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
	// EXTENSION METHODS
	/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
	
	/**
	 * Run the given function on all of this object's extensions
	 * 
	 * @param string $funcName The name of the function.
	 * @param mixed $arg An Argument to be passed to each of the extension functions.
	 */
	public function extend($funcName, &$arg) {
		if($this->extension_instances) {
			foreach($this->extension_instances as $extension) {
				if($extension->hasMethod($funcName)) {
					$extension->$funcName($arg);
				}
			}
		}
	}
	
	/**
	 * Get an extension on this DataObject
	 * 
	 * @param string $name Classname of the Extension (e.g. 'Versioned')
	 * 
	 * @return DataObjectDecorator The instance of the extension
	 */
	public function getExtension($name) {
		return $this->extension_instances[$name];
	}
	
	/**
	 * Returns true if the given extension class is attached to this object
	 * 
	 * @param string $requiredExtension Classname of the extension
	 * 
	 * @return boolean True if the given extension class is attached to this object
	 */
	public function hasExtension($requiredExtension) {
		return isset($this->extension_instances[$requiredExtension]) ? true : false;
	}

	/**
	 * Add an extension to the given object.
	 * This can be used to add extensions to built-in objects, such as role decorators on Member 
	 */
	public static function add_extension($className, $extensionName) {
		Object::addStaticVars($className, array(
			'extensions' => array(
				$extensionName,
			),
		));
	}
}

/**
 * PHP 5.2 has a namespace conflict with our datetime class,
 * for legacy support, we use this overload method.
 * // ENFORCE STRONG_CREATE
 */
Object::useCustomClass('Datetime','SSDatetime',true);
?>