inc/classes/main/handler/tasks/class_TaskHandler.php

   1 <?php
   2 /**
   3  * A Task handler
   4  *
   5  * @author              Roland Haeder <webmaster@shipsimu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2015 Core Developer Team
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.shipsimu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class TaskHandler extends BaseHandler implements Registerable, HandleableTask {
  25         // Exception constants
  26         const EXCEPTION_TASK_IS_INVALID = 0xb00;
  27
  28         /**
  29          * Protected constructor
  30          *
  31          * @return      void
  32          */
  33         protected function __construct () {
  34                 // Call parent constructor
  35                 parent::__construct(__CLASS__);
  36
  37                 // Set handler name
  38                 $this->setHandlerName('task');
  39         }
  40
  41         /**
  42          * Creates an instance of this class
  43          *
  44          * @return      $handlerInstance        An instance of a HandleableTask class
  45          */
  46         public static final function createTaskHandler () {
  47                 // Get new instance
  48                 $handlerInstance = new TaskHandler();
  49
  50                 // Output debug message
  51                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Initializing task handler.');
  52
  53                 // Init the task list
  54                 $handlerInstance->setListInstance(ObjectFactory::createObjectByConfiguredName('task_list_class'));
  55
  56                 // Get default instance
  57                 $handlerInstance->setIteratorInstance($handlerInstance->getListInstance()->getIterator());
  58
  59                 // Init visitor instance for faster loop
  60                 $handlerInstance->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('active_task_visitor_class'));
  61
  62                 // Register the first (and generic) idle-loop task
  63                 $taskInstance = ObjectFactory::createObjectByConfiguredName('idle_task_class');
  64                 $handlerInstance->registerTask('idle_loop', $taskInstance);
  65
  66                 // Output debug message
  67                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task handler initialized.');
  68
  69                 // Return the prepared instance
  70                 return $handlerInstance;
  71         }
  72
  73         /**
  74          * Tries to execute the given task. If as task should not be started (yet)
  75          * or the interval time (see task_interval_delay) is not yet reached the
  76          * task is quietly skipped.
  77          *
  78          * @return      void
  79          * @throws      InvalidTaskException    If the current task is invalid
  80          */
  81         private function executeCurrentTask () {
  82                 // Update no task by default
  83                 $updateTask = FALSE;
  84
  85                 // Is the current task valid?
  86                 if (!$this->getListInstance()->getIterator()->valid()) {
  87                         // Not valid!
  88                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  89                 } // END - if
  90
  91                 // Get current task
  92                 $currentTask = $this->getListInstance()->getIterator()->current();
  93
  94                 // Is the task not yet started?
  95                 if ($currentTask['task_started'] === FALSE) {
  96                         // Determine difference between current time and registration
  97                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
  98
  99                         // Should we start now?
 100                         if ($diff < $currentTask['task_startup_delay']) {
 101                                 // Skip this silently
 102                                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task ' . $currentTask['id'] . ' not started: diff=' . $diff . ',task_startup_delay=' . $currentTask['task_startup_delay']);
 103                                 return;
 104                         } // END - if
 105
 106                         // Launch the task and mark it as updated
 107                         $currentTask['task_started'] = TRUE;
 108                         $updateTask = TRUE;
 109
 110                         // Debug message
 111                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 112                 } // END - if
 113
 114                 // Get time difference from interval delay
 115                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 116
 117                 // Debug message
 118                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task ' . $currentTask['id'] . ' diff=' . $diff . ',task_interval_delay=' . $currentTask['task_interval_delay'] . ',task_max_runs=' . $currentTask['task_max_runs'] . ',task_total_runs=' . $currentTask['task_total_runs']);
 119
 120                 // Is the interval delay reached?
 121                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_max_runs'] > 0) && ($currentTask['task_total_runs'] == $currentTask['task_max_runs']))) {
 122                         // Should we update the task from startup?
 123                         if ($updateTask === TRUE) {
 124                                 // Update the task before leaving
 125                                 $this->updateTask($currentTask);
 126                         } // END - if
 127
 128                         // Skip this silently
 129                         return;
 130                 } // END - if
 131
 132                 // Set last activity
 133                 $currentTask['task_last_activity'] = $this->getMilliTime();
 134
 135                 // Count this run
 136                 $currentTask['task_total_runs']++;
 137
 138                 // Update the task
 139                 $this->updateTask($currentTask);
 140
 141                 // And visit/run it
 142                 // @TODO Messurement can be added around this call
 143                 $currentTask['task_instance']->accept($this->getVisitorInstance());
 144         }
 145
 146         /**
 147          * Updates given task by updating the underlaying list
 148          *
 149          * @param       $taskEntry      An array with a task
 150          * @return      void
 151          */
 152         private function updateTask (array $taskEntry) {
 153                 // Get the key from current iteration
 154                 $key = $this->getListInstance()->getIterator()->key();
 155
 156                 // Get the hash from key
 157                 $hash = $this->getListInstance()->getHash($key);
 158
 159                 // Update the entry
 160                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 161         }
 162
 163         /**
 164          * Unregisters the given task
 165          *
 166          * @param       $taskData       Data of the task
 167          * @return      void
 168          */
 169         private function unregisterTask (array $taskData) {
 170                 // Debug output
 171                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - CALLED!');
 172
 173                 // Remove the entry
 174                 $this->getListInstance()->removeEntry('tasks', $taskData);
 175
 176                 // Debug output
 177                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - EXIT!');
 178          }
 179
 180         /**
 181          * Searches a task by given instance
 182          *
 183          * @param       $taskInstanc    An instanceof a Taskable class
 184          * @return      $taskName               Name of the task as used while registration
 185          */
 186         public function searchTask (Taskable $taskInstance) {
 187                 // Default is an empty (not found) task name
 188                 $taskName = '';
 189
 190                 // Get whole list
 191                 $taskList = $this->getListInstance()->getArrayFromList('tasks');
 192
 193                 // Search all instances
 194                 foreach ($taskList as $currentTask) {
 195                         // Does it match given task instance?
 196                         if ($currentTask['task_instance']->equals($taskInstance)) {
 197                                 // Found it
 198                                 $taskName = $currentTask['id'];
 199
 200                                 // Abort here
 201                                 break;
 202                         } // END - if
 203                 } // END - foreach
 204
 205                 // Return found name
 206                 return $taskName;
 207         }
 208
 209         /**
 210          * Registers a task with a task handler.
 211          *
 212          * @param       $taskName               A task name to register the task on
 213          * @param       $taskInstance   The instance we should register as a task
 214          * @return      void
 215          */
 216         public function registerTask ($taskName, Visitable $taskInstance) {
 217                 // Get interval delay
 218                 $intervalDelay = $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay');
 219                 $startupDelay  = $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay');
 220
 221                 // If the task is 'idle_loop', a deplay of zero seconds is fine
 222                 assert($intervalDelay >= 0);
 223                 assert(($taskName != 'idle_loop') && ($intervalDelay > 0));
 224                 assert(($taskName != 'idle_loop') && ($startupDelay > 0));
 225
 226                 // Create the entry
 227                 $taskEntry = array(
 228                         // Identifier for the generateHash() method
 229                         'id'                  => $taskName,
 230                         // Whether the task is started
 231                         'task_started'        => FALSE,
 232                         // Whether the task is paused (not yet implemented)
 233                         'task_paused'         => FALSE,
 234                         // Whether the task can be paused (not yet implemented)
 235                         'task_pauseable'      => TRUE,
 236                         // Timestamp of registration
 237                         'task_registered'     => $this->getMilliTime(),
 238                         // Last activity timestamp
 239                         'task_last_activity'  => 0,
 240                         // Total runs of this task
 241                         'task_total_runs'     => 0,
 242                         // Task instance itself
 243                         'task_instance'       => $taskInstance,
 244                         // Startup delay in milliseconds
 245                         'task_startup_delay'  => $startupDelay,
 246                         // Interval time (delay) in milliseconds before this task is executed again
 247                         'task_interval_delay' => $intervalDelay,
 248                         // How often should this task run?
 249                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 250                 );
 251
 252                 // Add the entry
 253                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 254
 255                 // Debug message
 256                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Task registered: taskName=' . $taskName .
 257                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 258                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 259                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 260                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' ...'
 261                 );
 262         }
 263
 264         /**
 265          * Checks whether tasks are left including idle task
 266          *
 267          * @return      $tasksLeft      Whether there are tasks left to handle
 268          */
 269         public function hasTasksLeft () {
 270                 // Do we have tasks there?
 271                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 272
 273                 // Return result
 274                 return $tasksLeft;
 275         }
 276
 277         /**
 278          * Handles all tasks by checking if they should startup or if it is their
 279          * turn to run. You should use this method in a while() loop in conjuntion
 280          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 281          * which will attempt to remove all tasks from the task handler.
 282          *
 283          * @return      void
 284          */
 285         public function handleTasks () {
 286                 // Should we rewind?
 287                 if (!$this->getListInstance()->getIterator()->valid()) {
 288                         // Rewind to the beginning for next loop
 289                         $this->getListInstance()->getIterator()->rewind();
 290                 } // END - if
 291
 292                 // Try to execute the task
 293                 $this->executeCurrentTask();
 294
 295                 // Go to next entry
 296                 $this->getListInstance()->getIterator()->next();
 297         }
 298
 299         /**
 300          * Shuts down all tasks and the task handler itself. This method should be
 301          * called from a corresponding filter class.
 302          *
 303          * @return      void
 304          */
 305         public function doShutdown () {
 306                 // Always rewind to the beginning for next loop
 307                 $this->getListInstance()->getIterator()->rewind();
 308
 309                 // Debug message
 310                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 311
 312                 // Remember all tasks that has been shutdown for removal
 313                 $tasks = array();
 314
 315                 // Instance a visitor
 316                 $this->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('shutdown_task_visitor_class'));
 317
 318                 // Shutdown all tasks in once go
 319                 while ($this->getListInstance()->getIterator()->valid()) {
 320                         // Get current entry
 321                         $currentTask = $this->getListInstance()->getIterator()->current();
 322
 323                         // Output debug message
 324                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutting down task ' . $currentTask['id'] . ' (taskInstance=' . $currentTask['task_instance']->__toString() . ') ...');
 325
 326                         // Shutdown the task
 327                         $currentTask['task_instance']->accept($this->getVisitorInstance());
 328
 329                         // Remember this task
 330                         array_push($tasks, $currentTask);
 331
 332                         // Advance to next one
 333                         $this->getListInstance()->getIterator()->next();
 334                 } // END - while
 335
 336                 // Debug message
 337                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __METHOD__ . ':' . __LINE__ . ']: Shutdown of all tasks completed.');
 338
 339                 // Remove all tasks
 340                 foreach ($tasks as $entry) {
 341                         $this->unregisterTask($entry);
 342                 } // END - foreach
 343         }
 344 }
 345
 346 // [EOF]
 347 ?>