8 files changed, 103 insertions, 12 deletions
diff --git a/phpBB/config/installer/container/services_install_console.yml b/phpBB/config/installer/container/services_install_console.yml
index 9a4808b6aa..5a1e898754 100644
--- a/phpBB/config/installer/container/services_install_console.yml
+++ b/phpBB/config/installer/container/services_install_console.yml
@@ -21,6 +21,7 @@ services:
             - @language
             - @installer.helper.iohandler_factory
             - @installer.installer.install
+            - @installer.helper.install_helper
         tags:
             - { name: console.installer.command }
 
diff --git a/phpBB/config/installer/container/services_install_controller.yml b/phpBB/config/installer/container/services_install_controller.yml
index c8d140aa5f..7acc7025a6 100644
--- a/phpBB/config/installer/container/services_install_controller.yml
+++ b/phpBB/config/installer/container/services_install_controller.yml
@@ -30,3 +30,4 @@ services:
             - @template
             - @request
             - @installer.installer.install
+            - @installer.helper.install_helper
diff --git a/phpBB/config/installer/container/services_installer.yml b/phpBB/config/installer/container/services_installer.yml
index 8e19be5c0c..62137aa9d8 100644
--- a/phpBB/config/installer/container/services_installer.yml
+++ b/phpBB/config/installer/container/services_installer.yml
@@ -56,6 +56,12 @@ services:
             - %core.root_path%
             - %core.php_ext%
 
+    installer.helper.install_helper:
+        class: phpbb\install\helper\install_helper
+        arguments:
+            - %core.root_path%
+            - %core.php_ext%
+
 # -------- Installer --------------------------------
     installer.module_base:
         abstract: true
diff --git a/phpBB/language/en/install.php b/phpBB/language/en/install.php
index f050d49ebd..10d25b0311 100644
--- a/phpBB/language/en/install.php
+++ b/phpBB/language/en/install.php
@@ -113,7 +113,8 @@ $lang = array_merge($lang, array(
 
 // General error messages
 $lang = array_merge($lang, array(
-	'INST_ERR_MISSING_DATA' => 'You must fill out all fields in this block.',
+	'INST_ERR_MISSING_DATA'		=> 'You must fill out all fields in this block.',
+	'PHPBB_ALREADY_INSTALLED'	=> 'phpBB is already installed.'
 ));
 
 // Data obtaining translations
diff --git a/phpBB/phpbb/install/console/command/install/install.php b/phpBB/phpbb/install/console/command/install/install.php
index d3f6d363f8..e9b4192ded 100644
--- a/phpBB/phpbb/install/console/command/install/install.php
+++ b/phpBB/phpbb/install/console/command/install/install.php
@@ -14,6 +14,7 @@
 namespace phpbb\install\console\command\install;
 
 use phpbb\install\exception\installer_exception;
+use phpbb\install\helper\install_helper;
 use phpbb\install\helper\iohandler\cli_iohandler;
 use phpbb\install\helper\iohandler\factory;
 use phpbb\install\installer;
@@ -41,6 +42,11 @@ class install extends \phpbb\console\command\command
 	protected $installer;
 
 	/**
+	 * @var install_helper
+	 */
+	protected $install_helper;
+
+	/**
 	 * @var language
 	 */
 	protected $language;
@@ -48,21 +54,22 @@ class install extends \phpbb\console\command\command
 	/**
 	 * Constructor
 	 *
-	 * @param language $language
-	 * @param factory $factory
-	 * @param installer $installer
+	 * @param language			$language
+	 * @param factory			$factory
+	 * @param installer			$installer
+	 * @param install_helper	$install_helper
 	 */
-	public function __construct(language $language, factory $factory, installer $installer)
+	public function __construct(language $language, factory $factory, installer $installer, install_helper $install_helper)
 	{
 		$this->iohandler_factory = $factory;
 		$this->installer = $installer;
 		$this->language = $language;
+		$this->install_helper = $install_helper;
 
 		parent::__construct(new \phpbb\user($language, 'datetime'));
 	}
 
 	/**
-	 *
 	 * {@inheritdoc}
 	 */
 	protected function configure()
@@ -89,8 +96,6 @@ class install extends \phpbb\console\command\command
 	 */
 	protected function execute(InputInterface $input, OutputInterface $output)
 	{
-		// @todo check that phpBB is not already installed
-
 		$this->iohandler_factory->set_environment('cli');
 
 		/** @var \phpbb\install\helper\iohandler\cli_iohandler $iohandler */
@@ -102,6 +107,11 @@ class install extends \phpbb\console\command\command
 
 		$config_file = $input->getArgument('config-file');
 
+		if ($this->install_helper->is_phpbb_installed())
+		{
+			$iohandler->add_error_message('PHPBB_ALREADY_INSTALLED');
+		}
+
 		if (!is_file($config_file))
 		{
 			$iohandler->add_error_message(array('MISSING_FILE', array($config_file)));
diff --git a/phpBB/phpbb/install/controller/helper.php b/phpBB/phpbb/install/controller/helper.php
index 5ef98ac2bb..a16298c525 100644
--- a/phpBB/phpbb/install/controller/helper.php
+++ b/phpBB/phpbb/install/controller/helper.php
@@ -219,7 +219,7 @@ class helper
 	protected function render_language_select()
 	{
 		$langs = $this->lang_helper->get_available_languages();
-		// @todo
+		// @todo Implement language change option
 	}
 
 	/**
diff --git a/phpBB/phpbb/install/controller/install.php b/phpBB/phpbb/install/controller/install.php
index c742906305..5cd42fcb84 100644
--- a/phpBB/phpbb/install/controller/install.php
+++ b/phpBB/phpbb/install/controller/install.php
@@ -13,7 +13,9 @@
 
 namespace phpbb\install\controller;
 
+use phpbb\exception\http_exception;
 use phpbb\install\helper\config;
+use phpbb\install\helper\install_helper;
 use phpbb\install\helper\navigation\navigation_provider;
 use Symfony\Component\HttpFoundation\StreamedResponse;
 use Symfony\Component\HttpFoundation\Response;
@@ -70,6 +72,11 @@ class install
 	protected $installer;
 
 	/**
+	 * @var install_helper
+	 */
+	protected $install_helper;
+
+	/**
 	 * Constructor
 	 *
 	 * @param helper 				$helper
@@ -80,8 +87,9 @@ class install
 	 * @param template				$template
 	 * @param request_interface		$request
 	 * @param installer				$installer
+	 * @param install_helper		$install_helper
 	 */
-	public function __construct(helper $helper, config $install_config, factory $factory, navigation_provider $nav_provider, language $language, template $template, request_interface $request, installer $installer)
+	public function __construct(helper $helper, config $install_config, factory $factory, navigation_provider $nav_provider, language $language, template $template, request_interface $request, installer $installer, install_helper $install_helper)
 	{
 		$this->controller_helper	= $helper;
 		$this->installer_config		= $install_config;
@@ -91,6 +99,7 @@ class install
 		$this->template				= $template;
 		$this->request				= $request;
 		$this->installer			= $installer;
+		$this->install_helper		= $install_helper;
 	}
 
 	/**
@@ -100,8 +109,6 @@ class install
 	 */
 	public function handle()
 	{
-		// @todo check that phpBB is not already installed
-
 		$this->template->assign_vars(array(
 			'U_ACTION' => $this->controller_helper->route('phpbb_installer_install'),
 		));
@@ -124,6 +131,11 @@ class install
 		/** @var \phpbb\install\helper\iohandler\iohandler_interface $iohandler */
 		$iohandler = $this->iohandler_factory->get();
 
+		if ($this->install_helper->is_phpbb_installed())
+		{
+			throw new http_exception(404, 'PAGE_NOT_FOUND');
+		}
+
 		// Set active navigation stage
 		if (isset($nav_data['active']) && is_array($nav_data['active']))
 		{
diff --git a/phpBB/phpbb/install/helper/install_helper.php b/phpBB/phpbb/install/helper/install_helper.php
new file mode 100644
index 0000000000..c1506de5bf
--- /dev/null
+++ b/phpBB/phpbb/install/helper/install_helper.php
@@ -0,0 +1,60 @@
+<?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\install\helper;
+
+/**
+ * General helper functionality for the installer
+ */
+class install_helper
+{
+	/**
+	 * @var string
+	 */
+	protected $php_ext;
+
+	/**
+	 * @var string
+	 */
+	protected $phpbb_root_path;
+
+	/**
+	 * Constructor
+	 *
+	 * @param string	$phpbb_root_path	path to phpBB's root
+	 * @param string	$php_ext			Extension of PHP files
+	 */
+	public function __construct($phpbb_root_path, $php_ext)
+	{
+		$this->phpbb_root_path	= $phpbb_root_path;
+		$this->php_ext			= $php_ext;
+	}
+
+	/**
+	 * Check whether phpBB is installed.
+	 *
+	 * @return bool
+	 */
+	public function is_phpbb_installed()
+	{
+		$config_path = $this->phpbb_root_path . 'config' . $this->php_ext;
+		$install_lock_path = $this->phpbb_root_path . 'cache/install_lock';
+
+		if (file_exists($config_path) && !file_exists($install_lock_path))
+		{
+			include_once $config_path;
+		}
+
+		return defined('PHPBB_INSTALLED');
+	}
+}