1: <?php
  2: /**
  3:  *
  4:  */
  5: abstract class Sidecar_Singleton_Base {
  6: 
  7:   /**
  8:    * @var Sidecar_Singleton_Base
  9:    */
 10:   private static $_instances = array();
 11: 
 12:   /**
 13:    * Bool to holds on to >=PHP 5.3 check
 14:    */
 15:   private static $_is_php53;
 16: 
 17:   /**
 18:    * @param array $args
 19:    */
 20:   function __construct( $args = array() ) {
 21:     if ( ! isset( self::$_is_php53 ) )
 22:       self::$_is_php53 = version_compare( PHP_VERSION, '5.3.0', '>=' );
 23: 
 24:     $this_class = get_class( $this );
 25: 
 26:     if ( isset( self::$_instances[$this_class] ) ) {
 27:       $message = __( '%s is a singleton class and cannot be instantiated more than once.', 'sidecar' );
 28:       Sidecar::show_error( $message , self::_get_called_class() );
 29:       exit;
 30:     }
 31: 
 32:     self::$_instances[$this_class] = &$this;
 33: 
 34:     if ( method_exists( $this, 'on_load' ) ) {
 35:       $this->on_load( $args );
 36:     }
 37:   }
 38: 
 39:   /**
 40:    * @return Sidecar_Singleton_Base
 41:    */
 42:   static function this() {
 43:     return self::$_instances[self::_get_called_class()];
 44:   }
 45: 
 46:   /**
 47:    * Clean syntax to access the value on an instance variable for a Singleton class
 48:    *
 49:    * @param $instance_var_name
 50:    *
 51:    * @return mixed
 52:    */
 53:   static function get( $instance_var_name ) {
 54:     $instance = self::_get_instance( self::_get_called_class() );
 55:     return isset( $instance->$instance_var_name ) ? $instance->$instance_var_name : null;
 56:   }
 57: 
 58:   /**
 59:    * Clean syntax to call a method on an instance variable for a Singleton class
 60:    *
 61:    * @param string $method_name
 62:    *
 63:    * @return mixed
 64:    */
 65:   static function call( $method_name ) {
 66:     if ( method_exists( $called_class = self::_get_called_class(), $method_name ) ) {
 67:       $args = func_get_args();
 68:       array_shift( $args );
 69:       $result = call_user_func_array( array( self::_get_instance( $called_class ), $method_name ), $args );
 70:     }
 71:     return isset( $result ) ? $result : null;
 72:   }
 73: 
 74:   /**
 75:    *
 76:    */
 77:   private static function _get_instance( $called_class ) {
 78:     if ( ! isset( self::$_instances[$called_class] ) )
 79:       self::$_instances[$called_class] = new $called_class();
 80:     return self::$_instances[$called_class];
 81:   }
 82: 
 83:   /**
 84:      * Adds a filter hook for an object
 85:      *
 86:      *  $this->add_filter( 'wp_title' );
 87:      *  $this->add_filter( 'wp_title', 11 );
 88:      *  $this->add_filter( 'wp_title', 'special_func' );
 89:      *  $this->add_filter( 'wp_title', 'special_func', 11 );
 90:      *  $this->add_filter( 'wp_title', array( __CLASS__, 'class_func' ) );
 91:      *  $this->add_filter( 'wp_title', array( __CLASS__, 'class_func' ), 11 );
 92:      *
 93:      * @param string $action_name
 94:      * @param bool|int|string|array $callable_or_priority
 95:      * @param int $priority
 96:      * @return mixed
 97:      */
 98:     function add_filter( $action_name, $callable_or_priority = false, $priority = 10 ) {
 99:     $value = false;
100:         if ( ! $callable_or_priority ) {
101:             $value = add_filter( $action_name, array( $this, $action_name ), $priority, 99 );
102:         } else if ( is_numeric( $callable_or_priority ) ) {
103:             $value = add_filter( $action_name, array( $this, $action_name ), $callable_or_priority, 99 );
104:         } else if ( is_string( $callable_or_priority ) ) {
105:             $value = add_filter( $action_name, array( $this, $callable_or_priority ), $priority, 99 );
106:         } else if ( is_array( $callable_or_priority ) ) {
107:             $value = add_filter( $action_name, $callable_or_priority, $priority, 99 );
108:         }
109:         return $value;
110:     }
111:     /**
112:      * Adds an action hook for an objectx`x``x``  `
113:      *
114:      *  $this->add_action( 'init' );
115:      *  $this->add_action( 'init', 11 );
116:      *  $this->add_action( 'init', 'special_func' );
117:      *  $this->add_action( 'init', 'special_func', 11 );
118:      *  $this->add_action( 'init', array( __CLASS__, 'class_func' ) );
119:      *  $this->add_action( 'init', array( __CLASS__, 'class_func' ), 11 );
120:      *
121:      * @param string $action_name
122:      * @param bool|int|string|array $callable_or_priority
123:      * @param int $priority
124:      * @return mixed
125:      */
126:     function add_action( $action_name, $callable_or_priority = false, $priority = 10 ) {
127:         $this->add_filter( $action_name, $callable_or_priority, $priority );
128:     }
129: 
130:   /**
131:    * Return name of calling class.
132:    *
133:    * Provides (hacky) support for PHP < 5.3.
134:    *
135:    * @return string
136:    */
137:   protected static function _get_called_class() {
138:     static $classes = array();
139:     if ( self::$_is_php53 && ( ! defined( 'SIDECAR_DEBUG' ) || ! SIDECAR_DEBUG ) ) {
140:       return get_called_class();
141:     } else {
142:       /**
143:        * Simulate get_called_class() for < PHP 5.3
144:        * @see https://stackoverflow.com/a/7904487/102699 for our inspiration
145:        */
146:       $backtrace = debug_backtrace( false );
147:       $class_names = implode( '|', array_keys( self::$_instances ) );
148:       for( $level = 1; $level < count( $backtrace ); $level++ ) {
149:         $call = $backtrace[$level];
150:         $key = "{$call['file']}/{$call['function']}/{$call['line']}";
151:         if ( isset( $classes[$key] ) ) {
152:           break;
153:         } else {
154:           if ( empty( $call['file'] ) ) {
155:             /**
156:              * Added this for 5.2.x
157:              */
158:             continue;
159:           }
160:           $lines = file($call['file']);
161:           preg_match_all(
162:             "#({$class_names})::{$call['function']}(\s*|=|\()#",
163:             $lines[$call['line']-1],
164:             $matches
165:           );
166:           unset( $lines );
167:           if ( 0 == count( $matches[1] ) ) {
168:             continue;
169:           } if ( 1 < count( $matches[1] ) ) {
170:             $calls = implode( "::{$call['function']}() or ", $matches[1] ) . "{$call['function']}()";
171:             trigger_error( sprintf( __( 'Too many calls to static method ::%s() on line %d of %s; can only have one of: %s', 'sidecar' ),
172:               $call['function'], $call['line'], $call['file'], $calls
173:             ));
174:           } else {
175:             $classes[$key] = $matches[1][0];
176:             break;
177:           }
178:         }
179:       }
180: 
181:       if ( ! isset( $classes[$key] ) ) {
182:         /**
183:          * Added this for 5.2.x on uninstall
184:          */
185:         foreach( $backtrace as $call ) {
186:           if ( ! empty( $call['function'] ) && 'call_user_func_array' == $call['function'] &&
187:                ! empty( $call['file'] ) && preg_match( '#/wp-includes/plugin\.php$#', $call['file'] ) &&
188:                ! empty( $call['args'][0][0] ) && preg_match( "#^({$class_names})$#", $call['args'][0][0] ) ) {
189:             $key = "{$call['file']}/{$call['function']}/{$call['line']}";
190:             $classes[$key] = $call['args'][0][0];
191:             break;
192:           }
193:         }
194:       }
195:       return $classes[$key];
196:     }
197:   }
198: 
199: //  static function instantiate() {
200: //    $class_name = self::_get_hooked_class();
201: //    self::$_instances[$class_name] = new $class_name();
202: //  }
203: 
204:   /**
205:    * @return bool
206:    */
207:   private static function _get_hooked_class() {
208:     $hooked_class = false;
209:     $backtrace = debug_backtrace( false );
210:     for( $index = 2; $index < count( $backtrace ); $index++ ) {
211:       if ( 'call_user_func_array' == $backtrace[$index]['function'] ) {
212:         $hooked_class = $backtrace[$index]['args'][0][0];
213:         break;
214:       }
215:     }
216:     return $hooked_class;
217:   }
218: 
219: }
220: 
221: