vzlogger/backend/lib/Util/ClassLoader.php
2010-09-19 20:48:19 +02:00

215 lines
7 KiB
PHP

<?php
/**
* @copyright Copyright (c) 2010, The volkszaehler.org project
* @package util
* @license http://www.opensource.org/licenses/gpl-license.php GNU Public License
*/
/*
* This file is part of volkzaehler.org
*
* volkzaehler.org 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 3 of the License, or
* any later version.
*
* volkzaehler.org 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 volkszaehler.org. If not, see <http://www.gnu.org/licenses/>.
*/
namespace Volkszaehler\Util;
/**
* Classloader for volkszaehler and vendor libraries
*
* Namespace is mapped to the filesystem structure
*
* @package util
* @author Roman Borschel <roman@code-factory.org>
* @author Steffen Vogel <info@steffenvogel.de>
* @license http://www.opensource.org/licenses/lgpl-license.php Lesser GNU Public License
*/
class ClassLoader {
protected $fileExtension = '.php';
protected $namespace;
protected $includePath;
protected $namespaceSeparator = '\\';
/**
* Creates a new <tt>ClassLoader</tt> that loads classes of the
* specified namespace from the specified include path.
*
* If no include path is given, the ClassLoader relies on the PHP include_path.
* If neither a namespace nor an include path is given, the ClassLoader will
* be responsible for loading all classes, thereby relying on the PHP include_path.
*
* @param string $ns The namespace of the classes to load.
* @param string $includePath The base include path to use.
*/
public function __construct($ns = NULL, $includePath = NULL) {
$this->namespace = $ns;
$this->includePath = $includePath;
}
/**
* Sets the base include path for all class files in the namespace of this ClassLoader.
*
* @param string $includePath
*/
public function setIncludePath($includePath) {
$this->includePath = $includePath;
}
/**
* Gets the base include path for all class files in the namespace of this ClassLoader.
*
* @return string
*/
public function getIncludePath() {
return $this->includePath;
}
/**
* Sets the file extension of class files in the namespace of this ClassLoader.
*
* @param string $fileExtension
*/
public function setFileExtension($fileExtension) {
$this->fileExtension = $fileExtension;
}
/**
* Gets the file extension of class files in the namespace of this ClassLoader.
*
* @return string
*/
public function getFileExtension() {
return $this->fileExtension;
}
/**
* Registers this ClassLoader on the SPL autoload stack.
*/
public function register() {
spl_autoload_register(array($this, 'loadClass'));
}
/**
* Removes this ClassLoader from the SPL autoload stack.
*/
public function unregister() {
spl_autoload_unregister(array($this, 'loadClass'));
}
/**
* Loads the given class or interface.
*
* @param string $class The name of the class to load.
* @return boolean TRUE if the class has been successfully loaded, FALSE otherwise.
*/
public function loadClass($class) {
if ($this->namespace !== NULL && strpos($class, $this->namespace . $this->namespaceSeparator) !== 0) {
return FALSE;
}
$subNamespace = substr($class, strlen($this->namespace));
$parts = explode($this->namespaceSeparator, $subNamespace);
$path = implode(DIRECTORY_SEPARATOR, $parts);
require_once ($this->includePath !== NULL ? $this->includePath : '') . $path . $this->fileExtension;
return TRUE;
}
/**
* Asks this ClassLoader whether it can potentially load the class (file) with
* the given name.
*
* @param string $class The fully-qualified name of the class.
* @return boolean TRUE if this ClassLoader can load the class, FALSE otherwise.
*/
public function canLoadClass($class) {
if ($this->namespace !== NULL && strpos($class, $this->namespace . $this->namespaceSeparator) !== 0) {
return FALSE;
}
$subNamespace = substr($class, strlen($this->namespace));
$parts = explode($this->namespaceSeparator, $subNamespace);
$path = implode(DIRECTORY_SEPARATOR, $parts);
return file_exists(($this->includePath !== NULL ? $this->includePath . DIRECTORY_SEPARATOR : '') . $path . $this->fileExtension);
}
/**
* Checks whether a class with a given name exists. A class "exists" if it is either
* already defined in the current request or if there is an autoloader on the SPL
* autoload stack that is a) responsible for the class in question and b) is able to
* load a class file in which the class definition resides.
*
* If the class is not already defined, each autoloader in the SPL autoload stack
* is asked whether it is able to tell if the class exists. If the autoloader is
* a <tt>ClassLoader</tt>, {@link canLoadClass} is used, otherwise the autoload
* function of the autoloader is invoked and expected to return a value that
* evaluates to TRUE if the class (file) exists. As soon as one autoloader reports
* that the class exists, TRUE is returned.
*
* Note that, depending on what kinds of autoloaders are installed on the SPL
* autoload stack, the class (file) might already be loaded as a result of checking
* for its existence. This is not the case with a <tt>ClassLoader</tt>, who separates
* these responsibilities.
*
* @param string $class The fully-qualified name of the class.
* @return boolean TRUE if the class exists as per the definition given above, FALSE otherwise.
*/
public static function classExists($class) {
if (class_exists($class, FALSE)) {
return TRUE;
}
foreach (spl_autoload_functions() as $loader) {
if (is_array($loader)) { // array(???, ???)
if (is_object($loader[0])) {
if ($loader[0] instanceof ClassLoader) { // array($obj, 'methodName')
if ($loader[0]->canLoadClass($class)) {
return TRUE;
}
} else if ($loader[0]->{$loader[1]}($class)) {
return TRUE;
}
} else if ($loader[0]::$loader[1]($class)) { // array('className', 'methodName')
return TRUE;
}
} else if ($loader instanceof \Closure) { // function($class) {..}
if ($loader($class)) {
return TRUE;
}
} else if (is_string($loader) && $loader($class)) { // "MyClass::loadClass"
return TRUE;
}
}
return FALSE;
}
/**
* Gets the <tt>ClassLoader</tt> from the SPL autoload stack that is responsible
* for (and is able to load) the class with the given name.
*
* @param string $class The name of the class.
* @return The <tt>ClassLoader</tt> for the class or NULL if no such <tt>ClassLoader</tt> exists.
*/
public static function getClassLoader($class) {
foreach (spl_autoload_functions() as $loader) {
if (is_array($loader) && $loader[0] instanceof ClassLoader &&
$loader[0]->canLoadClass($class)) {
return $loader[0];
}
}
return NULL;
}
}
?>