1: <?php
  2: 
  3: namespace ModHelper;
  4: 
  5: /**
  6:  * @package ModHelper
  7:  * @since 1.0
  8:  * @see https://github.com/php-fig/fig-standards/blob/master/accepted/PSR-4-autoloader-examples.md#class-example
  9:  */
 10: class Psr4AutoloaderClass
 11: {
 12:     /**
 13:      * An associative array where the key is a namespace prefix and the value
 14:      * is an array of base directories for classes in that namespace.
 15:      *
 16:      * @var array
 17:      */
 18:     protected $prefixes = array();
 19: 
 20:     /**
 21:      * Register loader with SPL autoloader stack.
 22:      *
 23:      * @return void
 24:      */
 25:     public function register()
 26:     {
 27:         spl_autoload_register(array($this, 'loadClass'));
 28: 
 29:         return $this;
 30:     }
 31: 
 32:     /**
 33:      * Adds a base directory for a namespace prefix.
 34:      *
 35:      * @param string $prefix The namespace prefix.
 36:      * @param string $base_dir A base directory for class files in the
 37:      * namespace.
 38:      * @param bool $prepend If true, prepend the base directory to the stack
 39:      * instead of appending it; this causes it to be searched first rather
 40:      * than last.
 41:      * @return void
 42:      */
 43:     public function addNamespace($prefix, $base_dir, $prepend = false)
 44:     {
 45:         // normalize namespace prefix
 46:         $prefix = trim($prefix, '\\');
 47:         // normalize the base directory with a trailing separator
 48:         $base_dir = rtrim($base_dir, DIRECTORY_SEPARATOR) . '/';
 49:         // initialize the namespace prefix array
 50:         if (isset($this->prefixes[$prefix]) === false) {
 51:             $this->prefixes[$prefix] = array();
 52:         }
 53:         // retain the base directory for the namespace prefix
 54:         if ($prepend) {
 55:             array_unshift($this->prefixes[$prefix], $base_dir);
 56:         } else {
 57:             array_push($this->prefixes[$prefix], $base_dir);
 58:         }
 59: 
 60:         return $this;
 61:     }
 62: 
 63:     /**
 64:      * Loads the class file for a given class name.
 65:      *
 66:      * @param string $class The fully-qualified class name.
 67:      * @return mixed The mapped file name on success, or boolean false on
 68:      * failure.
 69:      */
 70:     public function loadClass($class)
 71:     {
 72:         // the current namespace prefix
 73:         $prefix = $class;
 74:         // work backwards through the namespace names of the fully-qualified
 75:         // class name to find a mapped file name
 76:         while (false !== $pos = strrpos($prefix, '\\')) {
 77:             // retain the trailing namespace separator in the prefix
 78:             $prefix = substr($class, 0, $pos);
 79:             // the rest is the relative class name
 80:             $relative_class = substr($class, $pos + 1);
 81:             // try to load a mapped file for the prefix and relative class
 82:             $mapped_file = $this->loadMappedFile($prefix, $relative_class);
 83:             if ($mapped_file) {
 84:                 return $mapped_file;
 85:             }
 86:         }
 87: 
 88:         // never found a mapped file
 89:         return false;
 90:     }
 91: 
 92:     /**
 93:      * Load the mapped file for a namespace prefix and relative class.
 94:      *
 95:      * @param string $prefix The namespace prefix.
 96:      * @param string $relative_class The relative class name.
 97:      * @return mixed Boolean false if no mapped file can be loaded, or the
 98:      * name of the mapped file that was loaded.
 99:      */
100:     protected function loadMappedFile($prefix, $relative_class)
101:     {
102:         // are there any base directories for this namespace prefix?
103:         if (isset($this->prefixes[$prefix]) === false) {
104:             return false;
105:         }
106:         // look through base directories for this namespace prefix
107:         foreach ($this->prefixes[$prefix] as $base_dir) {
108:             // replace the namespace prefix with the base directory,
109:             // replace namespace separators with directory separators
110:             // in the relative class name, append with .php
111:             $file = $base_dir
112:                 . str_replace('\\', '/', $relative_class)
113:                 . '.php';
114:             // if the mapped file exists, require it
115:             if ($this->requireFile($file)) {
116:                 // yes, we're done
117:                 return $file;
118:             }
119:         }
120: 
121:         // never found it
122:         return false;
123:     }
124: 
125:     /**
126:      * If a file exists, require it from the file system.
127:      *
128:      * @param string $file The file to require.
129:      * @return bool True if the file exists, false if not.
130:      */
131:     protected function requireFile($file)
132:     {
133:         if (file_exists($file)) {
134:             require $file;
135: 
136:             return true;
137:         }
138: 
139:         return false;
140:     }
141: }
142: