6 files changed, 1270 insertions, 0 deletions
diff --git a/phpBB/phpbb/extension/base.php b/phpBB/phpbb/extension/base.php
new file mode 100644
index 0000000000..cbbd7bc622
--- /dev/null
+++ b/phpBB/phpbb/extension/base.php
@@ -0,0 +1,131 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+* A base class for extensions without custom enable/disable/purge code.
+*/
+class base implements \phpbb\extension\extension_interface
+{
+	/** @var ContainerInterface */
+	protected $container;
+
+	/** @var \phpbb\finder */
+	protected $finder;
+
+	/** @var \phpbb\db\migrator */
+	protected $migrator;
+
+	/** @var string */
+	protected $extension_name;
+
+	/** @var string */
+	protected $extension_path;
+
+	/**
+	* Constructor
+	*
+	* @param ContainerInterface $container Container object
+	* @param \phpbb\finder $extension_finder
+	* @param string $extension_name Name of this extension (from ext.manager)
+	* @param string $extension_path Relative path to this extension
+	*/
+	public function __construct(ContainerInterface $container, \phpbb\finder $extension_finder, \phpbb\db\migrator $migrator, $extension_name, $extension_path)
+	{
+		$this->container = $container;
+		$this->extension_finder = $extension_finder;
+		$this->migrator = $migrator;
+
+		$this->extension_name = $extension_name;
+		$this->extension_path = $extension_path;
+	}
+
+	/**
+	* Single enable step that installs any included migrations
+	*
+	* @param mixed $old_state State returned by previous call of this method
+	* @return false Indicates no further steps are required
+	*/
+	public function enable_step($old_state)
+	{
+		$migrations = $this->get_migration_file_list();
+
+		$this->migrator->set_migrations($migrations);
+
+		$this->migrator->update();
+
+		return !$this->migrator->finished();
+	}
+
+	/**
+	* Single disable step that does nothing
+	*
+	* @param mixed $old_state State returned by previous call of this method
+	* @return false Indicates no further steps are required
+	*/
+	public function disable_step($old_state)
+	{
+		return false;
+	}
+
+	/**
+	* Single purge step that reverts any included and installed migrations
+	*
+	* @param mixed $old_state State returned by previous call of this method
+	* @return false Indicates no further steps are required
+	*/
+	public function purge_step($old_state)
+	{
+		$migrations = $this->get_migration_file_list();
+
+		$this->migrator->set_migrations($migrations);
+
+		foreach ($migrations as $migration)
+		{
+			while ($this->migrator->migration_state($migration) !== false)
+			{
+				$this->migrator->revert($migration);
+
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
+	* Get the list of migration files from this extension
+	*
+	* @return array
+	*/
+	protected function get_migration_file_list()
+	{
+		static $migrations = false;
+
+		if ($migrations !== false)
+		{
+			return $migrations;
+		}
+
+		// Only have the finder search in this extension path directory
+		$migrations = $this->extension_finder
+			->extension_directory('/migrations')
+			->find_from_extension($this->extension_name, $this->extension_path);
+		$migrations = $this->extension_finder->get_classes_from_files($migrations);
+
+		return $migrations;
+	}
+}
diff --git a/phpBB/phpbb/extension/exception.php b/phpBB/phpbb/extension/exception.php
new file mode 100644
index 0000000000..3f7d251a4e
--- /dev/null
+++ b/phpBB/phpbb/extension/exception.php
@@ -0,0 +1,25 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+/**
+ * Exception class for metadata
+ */
+class exception extends \UnexpectedValueException
+{
+	public function __toString()
+	{
+		return $this->getMessage();
+	}
+}
diff --git a/phpBB/phpbb/extension/extension_interface.php b/phpBB/phpbb/extension/extension_interface.php
new file mode 100644
index 0000000000..cc8b8be980
--- /dev/null
+++ b/phpBB/phpbb/extension/extension_interface.php
@@ -0,0 +1,63 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+/**
+* The interface extension meta classes have to implement to run custom code
+* on enable/disable/purge.
+*/
+interface extension_interface
+{
+	/**
+	* enable_step is executed on enabling an extension until it returns false.
+	*
+	* Calls to this function can be made in subsequent requests, when the
+	* function is invoked through a webserver with a too low max_execution_time.
+	*
+	* @param	mixed	$old_state	The return value of the previous call
+	*								of this method, or false on the first call
+	* @return	mixed				Returns false after last step, otherwise
+	*								temporary state which is passed as an
+	*								argument to the next step
+	*/
+	public function enable_step($old_state);
+
+	/**
+	* Disables the extension.
+	*
+	* Calls to this function can be made in subsequent requests, when the
+	* function is invoked through a webserver with a too low max_execution_time.
+	*
+	* @param	mixed	$old_state	The return value of the previous call
+	*								of this method, or false on the first call
+	* @return	mixed				Returns false after last step, otherwise
+	*								temporary state which is passed as an
+	*								argument to the next step
+	*/
+	public function disable_step($old_state);
+
+	/**
+	* purge_step is executed on purging an extension until it returns false.
+	*
+	* Calls to this function can be made in subsequent requests, when the
+	* function is invoked through a webserver with a too low max_execution_time.
+	*
+	* @param	mixed	$old_state	The return value of the previous call
+	*								of this method, or false on the first call
+	* @return	mixed				Returns false after last step, otherwise
+	*								temporary state which is passed as an
+	*								argument to the next step
+	*/
+	public function purge_step($old_state);
+}
diff --git a/phpBB/phpbb/extension/manager.php b/phpBB/phpbb/extension/manager.php
new file mode 100644
index 0000000000..b19eb9f8a3
--- /dev/null
+++ b/phpBB/phpbb/extension/manager.php
@@ -0,0 +1,591 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+use Symfony\Component\DependencyInjection\ContainerInterface;
+
+/**
+* The extension manager provides means to activate/deactivate extensions.
+*/
+class manager
+{
+	/** @var ContainerInterface */
+	protected $container;
+
+	protected $db;
+	protected $config;
+	protected $cache;
+	protected $user;
+	protected $php_ext;
+	protected $extensions;
+	protected $extension_table;
+	protected $phpbb_root_path;
+	protected $cache_name;
+
+	/**
+	* Creates a manager and loads information from database
+	*
+	* @param ContainerInterface $container A container
+	* @param \phpbb\db\driver\driver_interface $db A database connection
+	* @param \phpbb\config\config $config Config object
+	* @param \phpbb\filesystem $filesystem
+	* @param \phpbb\user $user User object
+	* @param string $extension_table The name of the table holding extensions
+	* @param string $phpbb_root_path Path to the phpbb includes directory.
+	* @param string $php_ext php file extension, defaults to php
+	* @param \phpbb\cache\driver\driver_interface $cache A cache instance or null
+	* @param string $cache_name The name of the cache variable, defaults to _ext
+	*/
+	public function __construct(ContainerInterface $container, \phpbb\db\driver\driver_interface $db, \phpbb\config\config $config, \phpbb\filesystem $filesystem, \phpbb\user $user, $extension_table, $phpbb_root_path, $php_ext = 'php', \phpbb\cache\driver\driver_interface $cache = null, $cache_name = '_ext')
+	{
+		$this->cache = $cache;
+		$this->cache_name = $cache_name;
+		$this->config = $config;
+		$this->container = $container;
+		$this->db = $db;
+		$this->extension_table = $extension_table;
+		$this->filesystem = $filesystem;
+		$this->phpbb_root_path = $phpbb_root_path;
+		$this->php_ext = $php_ext;
+		$this->user = $user;
+
+		$this->extensions = ($this->cache) ? $this->cache->get($this->cache_name) : false;
+
+		if ($this->extensions === false)
+		{
+			$this->load_extensions();
+		}
+	}
+
+	/**
+	* Loads all extension information from the database
+	*
+	* @return null
+	*/
+	public function load_extensions()
+	{
+		$this->extensions = array();
+
+		// Do not try to load any extensions when installing or updating
+		// Note: database updater invokes this code, and in 3.0
+		// there is no extension table therefore the rest of this function
+		// fails
+		if (defined('IN_INSTALL'))
+		{
+			return;
+		}
+
+		$sql = 'SELECT *
+			FROM ' . $this->extension_table;
+
+		$result = $this->db->sql_query($sql);
+		$extensions = $this->db->sql_fetchrowset($result);
+		$this->db->sql_freeresult($result);
+
+		foreach ($extensions as $extension)
+		{
+			$extension['ext_path'] = $this->get_extension_path($extension['ext_name']);
+			$this->extensions[$extension['ext_name']] = $extension;
+		}
+
+		ksort($this->extensions);
+
+		if ($this->cache)
+		{
+			$this->cache->put($this->cache_name, $this->extensions);
+		}
+	}
+
+	/**
+	* Generates the path to an extension
+	*
+	* @param string $name The name of the extension
+	* @param bool $phpbb_relative Whether the path should be relative to phpbb root
+	* @return string Path to an extension
+	*/
+	public function get_extension_path($name, $phpbb_relative = false)
+	{
+		$name = str_replace('.', '', $name);
+
+		return (($phpbb_relative) ? $this->phpbb_root_path : '') . 'ext/' . $name . '/';
+	}
+
+	/**
+	* Instantiates the extension meta class for the extension with the given name
+	*
+	* @param string $name The extension name
+	* @return \phpbb\extension\extension_interface Instance of the extension meta class or
+	*                     \phpbb\extension\base if the class does not exist
+	*/
+	public function get_extension($name)
+	{
+		$extension_class_name = str_replace('/', '\\', $name) . '\\ext';
+
+		$migrator = $this->container->get('migrator');
+
+		if (class_exists($extension_class_name))
+		{
+			return new $extension_class_name($this->container, $this->get_finder(), $migrator, $name, $this->get_extension_path($name, true));
+		}
+		else
+		{
+			return new \phpbb\extension\base($this->container, $this->get_finder(), $migrator, $name, $this->get_extension_path($name, true));
+		}
+	}
+
+	/**
+	* Instantiates the metadata manager for the extension with the given name
+	*
+	* @param string $name The extension name
+	* @param \phpbb\template\template $template The template manager
+	* @return \phpbb\extension\metadata_manager Instance of the metadata manager
+	*/
+	public function create_extension_metadata_manager($name, \phpbb\template\template $template)
+	{
+		return new \phpbb\extension\metadata_manager($name, $this->config, $this, $template, $this->user, $this->phpbb_root_path);
+	}
+
+	/**
+	* Runs a step of the extension enabling process.
+	*
+	* Allows the exentension to enable in a long running script that works
+	* in multiple steps across requests. State is kept for the extension
+	* in the extensions table.
+	*
+	* @param	string	$name	The extension's name
+	* @return	bool			False if enabling is finished, true otherwise
+	*/
+	public function enable_step($name)
+	{
+		// ignore extensions that are already enabled
+		if (isset($this->extensions[$name]) && $this->extensions[$name]['ext_active'])
+		{
+			return false;
+		}
+
+		$old_state = (isset($this->extensions[$name]['ext_state'])) ? unserialize($this->extensions[$name]['ext_state']) : false;
+
+		$extension = $this->get_extension($name);
+		$state = $extension->enable_step($old_state);
+
+		$active = ($state === false);
+
+		$extension_data = array(
+			'ext_name'		=> $name,
+			'ext_active'	=> $active,
+			'ext_state'		=> serialize($state),
+		);
+
+		$this->extensions[$name] = $extension_data;
+		$this->extensions[$name]['ext_path'] = $this->get_extension_path($extension_data['ext_name']);
+		ksort($this->extensions);
+
+		$sql = 'SELECT COUNT(ext_name) as row_count
+			FROM ' . $this->extension_table . "
+			WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+		$result = $this->db->sql_query($sql);
+		$count = $this->db->sql_fetchfield('row_count');
+		$this->db->sql_freeresult($result);
+
+		if ($count)
+		{
+			$sql = 'UPDATE ' . $this->extension_table . '
+				SET ' . $this->db->sql_build_array('UPDATE', $extension_data) . "
+				WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+			$this->db->sql_query($sql);
+		}
+		else
+		{
+			$sql = 'INSERT INTO ' . $this->extension_table . '
+				' . $this->db->sql_build_array('INSERT', $extension_data);
+			$this->db->sql_query($sql);
+		}
+
+		if ($this->cache)
+		{
+			$this->cache->purge();
+		}
+
+		if ($active)
+		{
+			$this->config->increment('assets_version', 1);
+		}
+
+		return !$active;
+	}
+
+	/**
+	* Enables an extension
+	*
+	* This method completely enables an extension. But it could be long running
+	* so never call this in a script that has a max_execution time.
+	*
+	* @param string $name The extension's name
+	* @return null
+	*/
+	public function enable($name)
+	{
+		// @codingStandardsIgnoreStart
+		while ($this->enable_step($name));
+		// @codingStandardsIgnoreEnd
+	}
+
+	/**
+	* Disables an extension
+	*
+	* Calls the disable method on the extension's meta class to allow it to
+	* process the event.
+	*
+	* @param string $name The extension's name
+	* @return bool False if disabling is finished, true otherwise
+	*/
+	public function disable_step($name)
+	{
+		// ignore extensions that are already disabled
+		if (!isset($this->extensions[$name]) || !$this->extensions[$name]['ext_active'])
+		{
+			return false;
+		}
+
+		$old_state = unserialize($this->extensions[$name]['ext_state']);
+
+		$extension = $this->get_extension($name);
+		$state = $extension->disable_step($old_state);
+
+		// continue until the state is false
+		if ($state !== false)
+		{
+			$extension_data = array(
+				'ext_state'		=> serialize($state),
+			);
+			$this->extensions[$name]['ext_state'] = serialize($state);
+
+			$sql = 'UPDATE ' . $this->extension_table . '
+				SET ' . $this->db->sql_build_array('UPDATE', $extension_data) . "
+				WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+			$this->db->sql_query($sql);
+
+			if ($this->cache)
+			{
+				$this->cache->purge();
+			}
+
+			return true;
+		}
+
+		$extension_data = array(
+			'ext_active'	=> false,
+			'ext_state'		=> serialize(false),
+		);
+		$this->extensions[$name]['ext_active'] = false;
+		$this->extensions[$name]['ext_state'] = serialize(false);
+
+		$sql = 'UPDATE ' . $this->extension_table . '
+			SET ' . $this->db->sql_build_array('UPDATE', $extension_data) . "
+			WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+		$this->db->sql_query($sql);
+
+		if ($this->cache)
+		{
+			$this->cache->purge();
+		}
+
+		return false;
+	}
+
+	/**
+	* Disables an extension
+	*
+	* Disables an extension completely at once. This process could run for a
+	* while so never call this in a script that has a max_execution time.
+	*
+	* @param string $name The extension's name
+	* @return null
+	*/
+	public function disable($name)
+	{
+		// @codingStandardsIgnoreStart
+		while ($this->disable_step($name));
+		// @codingStandardsIgnoreEnd
+	}
+
+	/**
+	* Purge an extension
+	*
+	* Disables the extension first if active, and then calls purge on the
+	* extension's meta class to delete the extension's database content.
+	*
+	* @param string $name The extension's name
+	* @return bool False if purging is finished, true otherwise
+	*/
+	public function purge_step($name)
+	{
+		// ignore extensions that do not exist
+		if (!isset($this->extensions[$name]))
+		{
+			return false;
+		}
+
+		// disable first if necessary
+		if ($this->extensions[$name]['ext_active'])
+		{
+			$this->disable($name);
+		}
+
+		$old_state = unserialize($this->extensions[$name]['ext_state']);
+
+		$extension = $this->get_extension($name);
+		$state = $extension->purge_step($old_state);
+
+		// continue until the state is false
+		if ($state !== false)
+		{
+			$extension_data = array(
+				'ext_state'		=> serialize($state),
+			);
+			$this->extensions[$name]['ext_state'] = serialize($state);
+
+			$sql = 'UPDATE ' . $this->extension_table . '
+				SET ' . $this->db->sql_build_array('UPDATE', $extension_data) . "
+				WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+			$this->db->sql_query($sql);
+
+			if ($this->cache)
+			{
+				$this->cache->purge();
+			}
+
+			return true;
+		}
+
+		unset($this->extensions[$name]);
+
+		$sql = 'DELETE FROM ' . $this->extension_table . "
+			WHERE ext_name = '" . $this->db->sql_escape($name) . "'";
+		$this->db->sql_query($sql);
+
+		if ($this->cache)
+		{
+			$this->cache->purge();
+		}
+
+		return false;
+	}
+
+	/**
+	* Purge an extension
+	*
+	* Purges an extension completely at once. This process could run for a while
+	* so never call this in a script that has a max_execution time.
+	*
+	* @param string $name The extension's name
+	* @return null
+	*/
+	public function purge($name)
+	{
+		// @codingStandardsIgnoreStart
+		while ($this->purge_step($name));
+		// @codingStandardsIgnoreEnd
+	}
+
+	/**
+	* Retrieves a list of all available extensions on the filesystem
+	*
+	* @return array An array with extension names as keys and paths to the
+	*               extension as values
+	*/
+	public function all_available()
+	{
+		$available = array();
+		if (!is_dir($this->phpbb_root_path . 'ext/'))
+		{
+			return $available;
+		}
+
+		$iterator = new \RecursiveIteratorIterator(
+			new \phpbb\recursive_dot_prefix_filter_iterator(
+				new \RecursiveDirectoryIterator($this->phpbb_root_path . 'ext/', \FilesystemIterator::NEW_CURRENT_AND_KEY | \FilesystemIterator::FOLLOW_SYMLINKS)
+			),
+			\RecursiveIteratorIterator::SELF_FIRST
+		);
+		$iterator->setMaxDepth(2);
+
+		foreach ($iterator as $file_info)
+		{
+			if ($file_info->isFile() && $file_info->getFilename() == 'composer.json')
+			{
+				$ext_name = $iterator->getInnerIterator()->getSubPath();
+				$composer_file = $iterator->getPath() . '/composer.json';
+
+				// Ignore the extension if there is no composer.json.
+				if (!is_readable($composer_file) || !($ext_info = file_get_contents($composer_file)))
+				{
+					continue;
+				}
+
+				$ext_info = json_decode($ext_info, true);
+				$ext_name = str_replace(DIRECTORY_SEPARATOR, '/', $ext_name);
+
+				// Ignore the extension if directory depth is not correct or if the directory structure
+				// does not match the name value specified in composer.json.
+				if (substr_count($ext_name, '/') !== 1 || !isset($ext_info['name']) || $ext_name != $ext_info['name'])
+				{
+					continue;
+				}
+
+				$available[$ext_name] = $this->phpbb_root_path . 'ext/' . $ext_name . '/';
+			}
+		}
+		ksort($available);
+		return $available;
+	}
+
+	/**
+	* Retrieves all configured extensions.
+	*
+	* All enabled and disabled extensions are considered configured. A purged
+	* extension that is no longer in the database is not configured.
+	*
+	* @return array An array with extension names as keys and and the
+	*               database stored extension information as values
+	*/
+	public function all_configured()
+	{
+		$configured = array();
+		foreach ($this->extensions as $name => $data)
+		{
+			$data['ext_path'] = $this->phpbb_root_path . $data['ext_path'];
+			$configured[$name] = $data;
+		}
+		return $configured;
+	}
+
+	/**
+	* Retrieves all enabled extensions.
+	*
+	* @return array An array with extension names as keys and and the
+	*               database stored extension information as values
+	*/
+	public function all_enabled()
+	{
+		$enabled = array();
+		foreach ($this->extensions as $name => $data)
+		{
+			if ($data['ext_active'])
+			{
+				$enabled[$name] = $this->phpbb_root_path . $data['ext_path'];
+			}
+		}
+		return $enabled;
+	}
+
+	/**
+	* Retrieves all disabled extensions.
+	*
+	* @return array An array with extension names as keys and and the
+	*               database stored extension information as values
+	*/
+	public function all_disabled()
+	{
+		$disabled = array();
+		foreach ($this->extensions as $name => $data)
+		{
+			if (!$data['ext_active'])
+			{
+				$disabled[$name] = $this->phpbb_root_path . $data['ext_path'];
+			}
+		}
+		return $disabled;
+	}
+
+	/**
+	* Check to see if a given extension is available on the filesystem
+	*
+	* @param string $name Extension name to check NOTE: Can be user input
+	* @return bool Depending on whether or not the extension is available
+	*/
+	public function is_available($name)
+	{
+		return file_exists($this->get_extension_path($name, true));
+	}
+
+	/**
+	* Check to see if a given extension is enabled
+	*
+	* @param string $name Extension name to check
+	* @return bool Depending on whether or not the extension is enabled
+	*/
+	public function is_enabled($name)
+	{
+		return isset($this->extensions[$name]) && $this->extensions[$name]['ext_active'];
+	}
+
+	/**
+	* Check to see if a given extension is disabled
+	*
+	* @param string $name Extension name to check
+	* @return bool Depending on whether or not the extension is disabled
+	*/
+	public function is_disabled($name)
+	{
+		return isset($this->extensions[$name]) && !$this->extensions[$name]['ext_active'];
+	}
+
+	/**
+	* Check to see if a given extension is configured
+	*
+	* All enabled and disabled extensions are considered configured. A purged
+	* extension that is no longer in the database is not configured.
+	*
+	* @param string $name Extension name to check
+	* @return bool Depending on whether or not the extension is configured
+	*/
+	public function is_configured($name)
+	{
+		return isset($this->extensions[$name]);
+	}
+
+	/**
+	* Check to see if a given extension is purged
+	*
+	* An extension is purged if it is available, not enabled and not disabled.
+	*
+	* @param string $name Extension name to check
+	* @return bool Depending on whether or not the extension is purged
+	*/
+	public function is_purged($name)
+	{
+		return $this->is_available($name) && !$this->is_configured($name);
+	}
+
+	/**
+	* Instantiates a \phpbb\finder.
+	*
+	* @param bool $use_all_available Should we load all extensions, or just enabled ones
+	* @return \phpbb\finder An extension finder instance
+	*/
+	public function get_finder($use_all_available = false)
+	{
+		$finder = new \phpbb\finder($this->filesystem, $this->phpbb_root_path, $this->cache, $this->php_ext, $this->cache_name . '_finder');
+		if ($use_all_available)
+		{
+			$finder->set_extensions(array_keys($this->all_available()));
+		}
+		else
+		{
+			$finder->set_extensions(array_keys($this->all_enabled()));
+		}
+		return $finder;
+	}
+}
diff --git a/phpBB/phpbb/extension/metadata_manager.php b/phpBB/phpbb/extension/metadata_manager.php
new file mode 100644
index 0000000000..014d8c79c7
--- /dev/null
+++ b/phpBB/phpbb/extension/metadata_manager.php
@@ -0,0 +1,388 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+/**
+* The extension metadata manager validates and gets meta-data for extensions
+*/
+class metadata_manager
+{
+	/**
+	* phpBB Config instance
+	* @var \phpbb\config\config
+	*/
+	protected $config;
+
+	/**
+	* phpBB Extension Manager
+	* @var \phpbb\extension\manager
+	*/
+	protected $extension_manager;
+
+	/**
+	* phpBB Template instance
+	* @var \phpbb\template\template
+	*/
+	protected $template;
+
+	/**
+	* phpBB User instance
+	* @var \phpbb\user
+	*/
+	protected $user;
+
+	/**
+	* phpBB root path
+	* @var string
+	*/
+	protected $phpbb_root_path;
+
+	/**
+	* Name (including vendor) of the extension
+	* @var string
+	*/
+	protected $ext_name;
+
+	/**
+	* Metadata from the composer.json file
+	* @var array
+	*/
+	protected $metadata;
+
+	/**
+	* Link (including root path) to the metadata file
+	* @var string
+	*/
+	protected $metadata_file;
+
+	/**
+	* Creates the metadata manager
+	*
+	* @param string				$ext_name			Name (including vendor) of the extension
+	* @param \phpbb\config\config		$config				phpBB Config instance
+	* @param \phpbb\extension\manager	$extension_manager	An instance of the phpBB extension manager
+	* @param \phpbb\template\template	$template			phpBB Template instance
+	* @param \phpbb\user 		$user 				User instance
+	* @param string				$phpbb_root_path	Path to the phpbb includes directory.
+	*/
+	public function __construct($ext_name, \phpbb\config\config $config, \phpbb\extension\manager $extension_manager, \phpbb\template\template $template, \phpbb\user $user, $phpbb_root_path)
+	{
+		$this->config = $config;
+		$this->extension_manager = $extension_manager;
+		$this->template = $template;
+		$this->user = $user;
+		$this->phpbb_root_path = $phpbb_root_path;
+
+		$this->ext_name = $ext_name;
+		$this->metadata = array();
+		$this->metadata_file = '';
+	}
+
+	/**
+	* Processes and gets the metadata requested
+	*
+	* @param  string $element			All for all metadata that it has and is valid, otherwise specify which section you want by its shorthand term.
+	* @return array					Contains all of the requested metadata, throws an exception on failure
+	*/
+	public function get_metadata($element = 'all')
+	{
+		$this->set_metadata_file();
+
+		// Fetch the metadata
+		$this->fetch_metadata();
+
+		// Clean the metadata
+		$this->clean_metadata_array();
+
+		switch ($element)
+		{
+			case 'all':
+			default:
+				// Validate the metadata
+				if (!$this->validate())
+				{
+					return false;
+				}
+
+				return $this->metadata;
+			break;
+
+			case 'name':
+				return ($this->validate('name')) ? $this->metadata['name'] : false;
+			break;
+
+			case 'display-name':
+				if (isset($this->metadata['extra']['display-name']))
+				{
+					return $this->metadata['extra']['display-name'];
+				}
+				else
+				{
+					return ($this->validate('name')) ? $this->metadata['name'] : false;
+				}
+			break;
+		}
+	}
+
+	/**
+	* Sets the filepath of the metadata file
+	*
+	* @throws \phpbb\extension\exception
+	*/
+	private function set_metadata_file()
+	{
+		$ext_filepath = $this->extension_manager->get_extension_path($this->ext_name);
+		$metadata_filepath = $this->phpbb_root_path . $ext_filepath . 'composer.json';
+
+		$this->metadata_file = $metadata_filepath;
+
+		if (!file_exists($this->metadata_file))
+		{
+			throw new \phpbb\extension\exception($this->user->lang('FILE_NOT_FOUND', $this->metadata_file));
+		}
+	}
+
+	/**
+	* Gets the contents of the composer.json file
+	*
+	* @return bool True if success, throws an exception on failure
+	* @throws \phpbb\extension\exception
+	*/
+	private function fetch_metadata()
+	{
+		if (!file_exists($this->metadata_file))
+		{
+			throw new \phpbb\extension\exception($this->user->lang('FILE_NOT_FOUND', $this->metadata_file));
+		}
+		else
+		{
+			if (!($file_contents = file_get_contents($this->metadata_file)))
+			{
+				throw new \phpbb\extension\exception($this->user->lang('FILE_CONTENT_ERR', $this->metadata_file));
+			}
+
+			if (($metadata = json_decode($file_contents, true)) === null)
+			{
+				throw new \phpbb\extension\exception($this->user->lang('FILE_JSON_DECODE_ERR', $this->metadata_file));
+			}
+
+			$this->metadata = $metadata;
+
+			return true;
+		}
+	}
+
+	/**
+	* This array handles the cleaning of the array
+	*
+	* @return array Contains the cleaned metadata array
+	*/
+	private function clean_metadata_array()
+	{
+		return $this->metadata;
+	}
+
+	/**
+	* Validate fields
+	*
+	* @param string $name  ("all" for display and enable validation
+	* 						"display" for name, type, and authors
+	* 						"name", "type")
+	* @return Bool True if valid, throws an exception if invalid
+	* @throws \phpbb\extension\exception
+	*/
+	public function validate($name = 'display')
+	{
+		// Basic fields
+		$fields = array(
+			'name'		=> '#^[a-zA-Z0-9_\x7f-\xff]{2,}/[a-zA-Z0-9_\x7f-\xff]{2,}$#',
+			'type'		=> '#^phpbb-extension$#',
+			'license'	=> '#.+#',
+			'version'	=> '#.+#',
+		);
+
+		switch ($name)
+		{
+			case 'all':
+				$this->validate('display');
+
+				$this->validate_enable();
+			break;
+
+			case 'display':
+				foreach ($fields as $field => $data)
+				{
+					$this->validate($field);
+				}
+
+				$this->validate_authors();
+			break;
+
+			default:
+				if (isset($fields[$name]))
+				{
+					if (!isset($this->metadata[$name]))
+					{
+						throw new \phpbb\extension\exception($this->user->lang('META_FIELD_NOT_SET', $name));
+					}
+
+					if (!preg_match($fields[$name], $this->metadata[$name]))
+					{
+						throw new \phpbb\extension\exception($this->user->lang('META_FIELD_INVALID', $name));
+					}
+				}
+			break;
+		}
+
+		return true;
+	}
+
+	/**
+	* Validates the contents of the authors field
+	*
+	* @return boolean True when passes validation, throws exception if invalid
+	* @throws \phpbb\extension\exception
+	*/
+	public function validate_authors()
+	{
+		if (empty($this->metadata['authors']))
+		{
+			throw new \phpbb\extension\exception($this->user->lang('META_FIELD_NOT_SET', 'authors'));
+		}
+
+		foreach ($this->metadata['authors'] as $author)
+		{
+			if (!isset($author['name']))
+			{
+				throw new \phpbb\extension\exception($this->user->lang('META_FIELD_NOT_SET', 'author name'));
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	* This array handles the verification that this extension can be enabled on this board
+	*
+	* @return bool True if validation succeeded, False if failed
+	*/
+	public function validate_enable()
+	{
+		// Check for valid directory & phpBB, PHP versions
+		if (!$this->validate_dir() || !$this->validate_require_phpbb() || !$this->validate_require_php())
+		{
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	* Validates the most basic directory structure to ensure it follows <vendor>/<ext> convention.
+	*
+	* @return boolean True when passes validation
+	*/
+	public function validate_dir()
+	{
+		return (substr_count($this->ext_name, '/') === 1 && $this->ext_name == $this->get_metadata('name'));
+	}
+
+
+	/**
+	* Validates the contents of the phpbb requirement field
+	*
+	* @return boolean True when passes validation
+	*/
+	public function validate_require_phpbb()
+	{
+		if (!isset($this->metadata['require']['phpbb/phpbb']))
+		{
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	* Validates the contents of the php requirement field
+	*
+	* @return boolean True when passes validation
+	*/
+	public function validate_require_php()
+	{
+		if (!isset($this->metadata['require']['php']))
+		{
+			return false;
+		}
+
+		return true;
+	}
+
+	/**
+	* Version validation helper
+	*
+	* @param string $string The string for comparing to a version
+	* @param string $current_version The version to compare to
+	* @return bool True/False if meets version requirements
+	*/
+	private function _validate_version($string, $current_version)
+	{
+		// Allow them to specify their own comparison operator (ex: <3.1.2, >=3.1.0)
+		$comparison_matches = false;
+		preg_match('#[=<>]+#', $string, $comparison_matches);
+
+		if (!empty($comparison_matches))
+		{
+			return version_compare($current_version, str_replace(array($comparison_matches[0], ' '), '', $string), $comparison_matches[0]);
+		}
+
+		return version_compare($current_version, $string, '>=');
+	}
+
+	/**
+	* Outputs the metadata into the template
+	*
+	* @return null
+	*/
+	public function output_template_data()
+	{
+		$this->template->assign_vars(array(
+			'META_NAME'			=> htmlspecialchars($this->metadata['name']),
+			'META_TYPE'			=> htmlspecialchars($this->metadata['type']),
+			'META_DESCRIPTION'	=> (isset($this->metadata['description'])) ? htmlspecialchars($this->metadata['description']) : '',
+			'META_HOMEPAGE'		=> (isset($this->metadata['homepage'])) ? $this->metadata['homepage'] : '',
+			'META_VERSION'		=> (isset($this->metadata['version'])) ? htmlspecialchars($this->metadata['version']) : '',
+			'META_TIME'			=> (isset($this->metadata['time'])) ? htmlspecialchars($this->metadata['time']) : '',
+			'META_LICENSE'		=> htmlspecialchars($this->metadata['license']),
+
+			'META_REQUIRE_PHP'		=> (isset($this->metadata['require']['php'])) ? htmlspecialchars($this->metadata['require']['php']) : '',
+			'META_REQUIRE_PHP_FAIL'	=> !$this->validate_require_php(),
+
+			'META_REQUIRE_PHPBB'		=> (isset($this->metadata['require']['phpbb/phpbb'])) ? htmlspecialchars($this->metadata['require']['phpbb/phpbb']) : '',
+			'META_REQUIRE_PHPBB_FAIL'	=> !$this->validate_require_phpbb(),
+
+			'META_DISPLAY_NAME'	=> (isset($this->metadata['extra']['display-name'])) ? htmlspecialchars($this->metadata['extra']['display-name']) : '',
+		));
+
+		foreach ($this->metadata['authors'] as $author)
+		{
+			$this->template->assign_block_vars('meta_authors', array(
+				'AUTHOR_NAME'		=> htmlspecialchars($author['name']),
+				'AUTHOR_EMAIL'		=> (isset($author['email'])) ? $author['email'] : '',
+				'AUTHOR_HOMEPAGE'	=> (isset($author['homepage'])) ? $author['homepage'] : '',
+				'AUTHOR_ROLE'		=> (isset($author['role'])) ? htmlspecialchars($author['role']) : '',
+			));
+		}
+	}
+}
diff --git a/phpBB/phpbb/extension/provider.php b/phpBB/phpbb/extension/provider.php
new file mode 100644
index 0000000000..1c42cf7b5e
--- /dev/null
+++ b/phpBB/phpbb/extension/provider.php
@@ -0,0 +1,72 @@
+<?php
+/**
+*
+* This file is part of the phpBB Forum Software package.
+*
+* @copyright (c) phpBB Limited <https://www.phpbb.com>
+* @license GNU General Public License, version 2 (GPL-2.0)
+*
+* For full copyright and license information, please see
+* the docs/CREDITS.txt file.
+*
+*/
+
+namespace phpbb\extension;
+
+/**
+* Provides a set of items found in extensions.
+*
+* This abstract class is essentially a wrapper around item-specific
+* finding logic. It handles storing the extension manager via constructor
+* for the finding logic to use to find the items, and provides an
+* iterator interface over the items found by the finding logic.
+*
+* Items could be anything, for example template paths or cron task names.
+* Derived classes completely define what the items are.
+*/
+abstract class provider implements \IteratorAggregate
+{
+	/**
+	* Array holding all found items
+	* @var array|null
+	*/
+	protected $items = null;
+
+	/**
+	* An extension manager to search for items in extensions
+	* @var \phpbb\extension\manager
+	*/
+	protected $extension_manager;
+
+	/**
+	* Constructor. Loads all available items.
+	*
+	* @param \phpbb\extension\manager $extension_manager phpBB extension manager
+	*/
+	public function __construct(\phpbb\extension\manager $extension_manager)
+	{
+		$this->extension_manager = $extension_manager;
+	}
+
+	/**
+	* Finds items using the extension manager.
+	*
+	* @return array     List of task names
+	*/
+	abstract protected function find();
+
+	/**
+	* Retrieve an iterator over all items
+	*
+	* @return \ArrayIterator An iterator for the array of template paths
+	*/
+	public function getIterator()
+	{
+		if ($this->items === null)
+		{
+			$this->items = $this->find();
+		}
+
+		return new \ArrayIterator($this->items);
+	}
+}