dependencies.php

<?php
/**
 * Sort dependencies
 * 
 * This class sorts dependencies, this can be whatever.
 * The sorting algorithm used is @see http://en.wikipedia.org/wiki/Topological_sorting
 */

class Dependencies {
	public $sources = array();

	public function __construct() {
		
	}
	
	/**
	 * Add source
	 * @param {String} name Name of file
	 * @param {Array} dependencies
	 */
	public function add($name, $dependencies = array()) {
		
		// If dependencies is a string, split into array
		if(gettype($dependencies) == 'string') {
			$dependencies = preg_split('/,\s?/', $dependencies);
		}
	
		// Add 
		$this -> sources[$name] = (object) array(
			'name' => $name, 
			'dependencies' => (array) $dependencies
		);
	}
	
	/**
	 * Visit node, used in sorting
	 *
	 * This function checks all the dependencies of a node and calls 
	 * this function for each of them
	 */
	private function visit($source, &$sources, &$sorted) {
		
		// If source has not been visited
		if (!$source -> visited) {
		
			// Set that source has been visited
			$source -> visited = true;
			
			// Check each dependency
			foreach($source -> dependencies as $dependency) {
			
				// Call this function for each source
				if(isset($sources[$dependency])) {
					$this -> visit($sources[$dependency], $sources, $sorted);
				} else {
					exit(sprintf("The source '%s' depends on '%s' but there are no source with that name", $source -> name, $dependency) . PHP_EOL);
				}
				
			}
			
			// Add source to sorted array
			$sorted[] = $source;
		}
	}
	
	/**
	 * Sort dependencies and return array with sorted sources
	 * 
	 * @returns {Array} Sorted sources as array
	 */
	public function sort() {
		$sources = $this -> sources;
		$sorted = array();
		
		// Reset visited
		foreach($sources as $source) {
			$source -> visited = false;
		}
		
		// Loop through each source
		foreach($sources as $source) {
			// Set visited to true
			$this -> visit($source, $sources, $sorted);
		}
	
		// Just return sources
		return $sorted;
	}
}


?>