[feature/system-cron] Refactored cron task naming, loading and running.

PHPBB3-9596

phpBB/includes/cron/cron_manager.php

@@ -0,0 +1,175 @@
+<?php
+/**
+*
+* @package phpBB3
+* @version $Id$
+* @copyright (c) 2010 phpBB Group
+* @license http://opensource.org/licenses/gpl-license.php GNU Public License
+*
+*/
+
+/**
+* @ignore
+*/
+if (!defined('IN_PHPBB'))
+{
+	exit;
+}
+
+/**
+* Cron manager class.
+*
+* Finds installed cron tasks, stores task objects, provides task selection.
+*
+* @package phpBB3
+*/
+class cron_manager
+{
+	private $tasks = array();
+
+	public function __construct()
+	{
+		$task_files = $this->find_cron_task_files();
+		$this->load_tasks($task_files);
+	}
+
+	/**
+	* Finds cron task files.
+	*
+	* A cron task file must follow the naming convention:
+	* includes/cron/tasks/$mod/$name.php.
+	* $mod is core for tasks that are part of phpbb.
+	* Modifications should use their name as $mod.
+	* $name is the name of the cron task.
+	* Cron task is expected to be a class named cron_task_${mod}_${name}.
+	*
+	* Todo: consider caching found task file list in global cache.
+	*/
+	public function find_cron_task_files()
+	{
+		global $phpbb_root_path, $phpEx;
+
+		$tasks_root_path = $phpbb_root_path . 'includes/cron/tasks';
+		$dir = opendir($tasks_root_path);
+		$task_dirs = array();
+		while (($entry = readdir($dir)) !== false)
+		{
+			// ignore ., .. and dot directories
+			// todo: change is_dir to account for symlinks
+			if ($entry[0] == '.' || !is_dir($entry))
+			{
+				continue;
+			}
+			$task_dirs[] = $entry;
+		}
+		closedir($dir);
+
+		$ext = '.' . $phpEx;
+		$ext_length = strlen($ext);
+		$task_files = array();
+		foreach ($task_dirs as $task_dir)
+		{
+			$path = $phpbb_root_path . 'includes/cron/tasks/' . $task_dir;
+			$dir = opendir($path);
+			while (($entry = readdir($dir)) !== false && substr($entry, -$ext_length) == $ext)
+			{
+				$task_file = substr($entry, 0, -$ext_length);
+				$task_files[] = array($task_dir, $task_file);
+			}
+			closedir($dir);
+		}
+		return $task_files;
+	}
+
+	/**
+	* Checks whether $name is a valid identifier, and therefore part of valid cron task class name.
+	*/
+	public function is_valid_name($name)
+	{
+		return preg_match('/^[a-zA-Z][a-zA-Z0-9_]*$/', $name);
+	}
+
+	public function load_tasks($task_files)
+	{
+		global $phpbb_root_path, $phpEx;
+
+		foreach ($task_files as $task_file)
+		{
+			list($mod, $filename) = $task_file;
+			if ($this->is_valid_name($mod) && $this->is_valid_name($filename))
+			{
+				include_once($phpbb_root_path . "includes/cron/$mod/$filename.$phpEx");
+				$class = "cron_task_${mod}_${filename}";
+				$object = new $class;
+				$this->tasks[] = $object;
+			}
+		}
+	}
+
+	/**
+	* Finds a task that is ready to run.
+	*
+	* If several tasks are ready, any one of them could be returned.
+	*/
+	function find_one_ready_task()
+	{
+		foreach ($this->tasks as $task)
+		{
+			if ($task->is_ready())
+			{
+				return $task;
+			}
+		}
+		return null;
+	}
+
+	/**
+	* Finds all tasks that are ready to run.
+	*/
+	function find_all_ready_tasks()
+	{
+		$tasks = array();
+		foreach ($this->tasks as $task)
+		{
+			if ($task->is_ready())
+			{
+				$tasks[] = $task;
+			}
+		}
+		return $tasks;
+	}
+
+	/**
+	* Finds a task by name.
+	*
+	* Web runner uses this method to resolve names to tasks.
+	*/
+	function find_task($name)
+	{
+		foreach ($this->tasks as $task)
+		{
+			if ($task->get_name() == $name)
+			{
+				return $task;
+			}
+		}
+		return null;
+	}
+
+	function instantiate_task($name, $args)
+	{
+		$task = $this->find_task($name);
+		if ($task)
+		{
+			$class = get_class($task);
+			$task = new $class($args);
+		}
+		return $task;
+	}
+
+	function generate_generic_task_code($cron_type)
+	{
+		global $phpbb_root_path, $phpEx;
+		return '<img src="' . $url . '" width="1" height="1" alt="cron" />';
+	}
+}