Merge branch '252-extensions' into dev

8 files changed, 698 insertions, 46 deletions

diff --git a/lib/Minz/Configuration.php b/lib/Minz/Configuration.php
index 6044fc269..fe415e22b 100644
--- a/lib/Minz/Configuration.php
+++ b/lib/Minz/Configuration.php
@@ -101,6 +101,19 @@ class Minz_Configuration {
 	 */
 	private $configuration_setter = null;
 
+	public function removeExtension($ext_name) {
+		self::$extensions_enabled = array_diff(
+			self::$extensions_enabled,
+			array($ext_name)
+		);
+	}
+	public function addExtension($ext_name) {
+		$found = array_search($ext_name, self::$extensions_enabled) !== false;
+		if (!$found) {
+			self::$extensions_enabled[] = $ext_name;
+		}
+	}
+
 	/**
 	 * Create a new Minz_Configuration object.
 	 * 
diff --git a/lib/Minz/Dispatcher.php b/lib/Minz/Dispatcher.php
index f62a92911..125ce5757 100644
--- a/lib/Minz/Dispatcher.php
+++ b/lib/Minz/Dispatcher.php
@@ -15,6 +15,7 @@ class Minz_Dispatcher {
 	/* singleton */
 	private static $instance = null;
 	private static $needsReset;
+	private static $registrations = array();
 
 	private $controller;
 
@@ -38,7 +39,7 @@ class Minz_Dispatcher {
 			self::$needsReset = false;
 
 			try {
-				$this->createController ('FreshRSS_' . Minz_Request::controllerName () . '_Controller');
+				$this->createController (Minz_Request::controllerName ());
 				$this->controller->init ();
 				$this->controller->firstAction ();
 				if (!self::$needsReset) {
@@ -67,14 +68,18 @@ class Minz_Dispatcher {
 
 	/**
 	 * Instancie le Controller
-	 * @param $controller_name le nom du controller à instancier
+	 * @param $base_name le nom du controller à instancier
 	 * @exception ControllerNotExistException le controller n'existe pas
 	 * @exception ControllerNotActionControllerException controller n'est
 	 *          > pas une instance de ActionController
 	 */
-	private function createController ($controller_name) {
-		$filename = APP_PATH . self::CONTROLLERS_PATH_NAME . '/'
-		          . $controller_name . '.php';
+	private function createController ($base_name) {
+		if (self::isRegistered($base_name)) {
+			self::loadController($base_name);
+			$controller_name = 'FreshExtension_' . $base_name . '_Controller';
+		} else {
+			$controller_name = 'FreshRSS_' . $base_name . '_Controller';
+		}
 
 		if (!class_exists ($controller_name)) {
 			throw new Minz_ControllerNotExistException (
@@ -114,4 +119,42 @@ class Minz_Dispatcher {
 			$action_name
 		));
 	}
+
+	/**
+	 * Register a controller file.
+	 *
+	 * @param $base_name the base name of the controller (i.e. ./?c=<base_name>)
+	 * @param $base_path the base path where we should look into to find info.
+	 */
+	public static function registerController($base_name, $base_path) {
+		if (!self::isRegistered($base_name)) {
+			self::$registrations[$base_name] = $base_path;
+		}
+	}
+
+	/**
+	 * Return if a controller is registered.
+	 *
+	 * @param $base_name the base name of the controller.
+	 * @return true if the controller has been registered, false else.
+	 */
+	public static function isRegistered($base_name) {
+		return isset(self::$registrations[$base_name]);
+	}
+
+	/**
+	 * Load a controller file (include).
+	 *
+	 * @param $base_name the base name of the controller.
+	 */
+	private static function loadController($base_name) {
+		$base_path = self::$registrations[$base_name];
+		$controller_filename = $base_path . '/controllers/' . $base_name . 'Controller.php';
+		include_once $controller_filename;
+	}
+
+	private static function setViewPath($controller, $base_name) {
+		$base_path = self::$registrations[$base_name];
+		$controller->view()->setBasePathname($base_path);
+	}
 }
diff --git a/lib/Minz/Extension.php b/lib/Minz/Extension.php
new file mode 100644
index 000000000..b3991c129
--- /dev/null
+++ b/lib/Minz/Extension.php
@@ -0,0 +1,198 @@
+<?php
+
+/**
+ * The extension base class.
+ */
+class Minz_Extension {
+	private $name;
+	private $entrypoint;
+	private $path;
+	private $author;
+	private $description;
+	private $version;
+	private $type;
+
+	public static $authorized_types = array(
+		'system',
+		'user',
+	);
+
+	private $is_enabled;
+
+	/**
+	 * The constructor to assign specific information to the extension.
+	 *
+	 * Available fields are:
+	 * - name: the name of the extension (required).
+	 * - entrypoint: the extension class name (required).
+	 * - path: the pathname to the extension files (required).
+	 * - author: the name and / or email address of the extension author.
+	 * - description: a short description to describe the extension role.
+	 * - version: a version for the current extension.
+	 * - type: "system" or "user" (default).
+	 *
+	 * It must not be redefined by child classes.
+	 *
+	 * @param $meta_info contains information about the extension.
+	 */
+	public function __construct($meta_info) {
+		$this->name = $meta_info['name'];
+		$this->entrypoint = $meta_info['entrypoint'];
+		$this->path = $meta_info['path'];
+		$this->author = isset($meta_info['author']) ? $meta_info['author'] : '';
+		$this->description = isset($meta_info['description']) ? $meta_info['description'] : '';
+		$this->version = isset($meta_info['version']) ? $meta_info['version'] : '0.1';
+		$this->setType(isset($meta_info['type']) ? $meta_info['type'] : 'user');
+
+		$this->is_enabled = false;
+	}
+
+	/**
+	 * Used when installing an extension (e.g. update the database scheme).
+	 *
+	 * It must be redefined by child classes.
+	 */
+	public function install() {}
+
+	/**
+	 * Used when uninstalling an extension (e.g. revert the database scheme to
+	 * cancel changes from install).
+	 *
+	 * It must be redefined by child classes.
+	 */
+	public function uninstall() {}
+
+	/**
+	 * Call at the initialization of the extension (i.e. when the extension is
+	 * enabled by the extension manager).
+	 *
+	 * It must be redefined by child classes.
+	 */
+	public function init() {}
+
+	/**
+	 * Set the current extension to enable.
+	 */
+	public function enable() {
+		$this->is_enabled = true;
+	}
+
+	/**
+	 * Return if the extension is currently enabled.
+	 *
+	 * @return true if extension is enabled, false else.
+	 */
+	public function is_enabled() {
+		return $this->is_enabled;
+	}
+
+	/**
+	 * Return the content of the configure view for the current extension.
+	 *
+	 * @return the html content from ext_dir/configure.phtml, false if it does
+	 *         not exist.
+	 */
+	public function getConfigureView() {
+		$filename = $this->path . '/configure.phtml';
+		if (!file_exists($filename)) {
+			return false;
+		}
+
+		ob_start();
+		include($filename);
+		return ob_get_clean();
+	}
+
+	/**
+	 * Handle the configure action.
+	 *
+	 * It must be redefined by child classes.
+	 */
+	public function handleConfigureAction() {}
+
+	/**
+	 * Getters and setters.
+	 */
+	public function getName() {
+		return $this->name;
+	}
+	public function getEntrypoint() {
+		return $this->entrypoint;
+	}
+	public function getPath() {
+		return $this->path;
+	}
+	public function getAuthor() {
+		return $this->author;
+	}
+	public function getDescription() {
+		return $this->description;
+	}
+	public function getVersion() {
+		return $this->version;
+	}
+	public function getType() {
+		return $this->type;
+	}
+	private function setType($type) {
+		if (!in_array($type, self::$authorized_types)) {
+			throw new Minz_ExtensionException('invalid `type` info', $this->name);
+		}
+		$this->type = $type;
+	}
+
+	/**
+	 * Return the url for a given file.
+	 *
+	 * @param $filename name of the file to serve.
+	 * @param $type the type (js or css) of the file to serve.
+	 * @return the url corresponding to the file.
+	 */
+	public function getFileUrl($filename, $type) {
+		$dir = end(explode('/', $this->path));
+		$file_name_url = urlencode($dir . '/static/' . $filename);
+
+		$absolute_path = $this->path . '/static/' . $filename;
+		$mtime = @filemtime($absolute_path);
+
+		$url = '/ext.php?f=' . $file_name_url .
+		       '&amp;t=' . $type .
+		       '&amp;' . $mtime;
+		return Minz_Url::display($url);
+	}
+
+	/**
+	 * Register a controller in the Dispatcher.
+	 *
+	 * @param @base_name the base name of the controller. Final name will be:
+	 *                   FreshExtension_<base_name>_Controller.
+	 */
+	public function registerController($base_name) {
+		Minz_Dispatcher::registerController($base_name, $this->path);
+	}
+
+	/**
+	 * Register the views in order to be accessible by the application.
+	 */
+	public function registerViews() {
+		Minz_View::addBasePathname($this->path);
+	}
+
+	/**
+	 * Register i18n files from ext_dir/i18n/
+	 */
+	public function registerTranslates() {
+		$i18n_dir = $this->path . '/i18n';
+		Minz_Translate::registerPath($i18n_dir);
+	}
+
+	/**
+	 * Register a new hook.
+	 *
+	 * @param $hook_name the hook name (must exist).
+	 * @param $hook_function the function name to call (must be callable).
+	 */
+	public function registerHook($hook_name, $hook_function) {
+		Minz_ExtensionManager::addHook($hook_name, $hook_function, $this);
+	}
+}
diff --git a/lib/Minz/ExtensionException.php b/lib/Minz/ExtensionException.php
new file mode 100644
index 000000000..647f1a9b9
--- /dev/null
+++ b/lib/Minz/ExtensionException.php
@@ -0,0 +1,15 @@
+<?php
+
+class Minz_ExtensionException extends Minz_Exception {
+	public function __construct ($message, $extension_name = false, $code = self::ERROR) {
+		if ($extension_name) {
+			$message = 'An error occured in `' . $extension_name
+			         . '` extension with the message: ' . $message;
+		} else {
+			$message = 'An error occured in an unnamed '
+			         . 'extension with the message: ' . $message;
+		}
+
+		parent::__construct($message, $code);
+	}
+}
diff --git a/lib/Minz/ExtensionManager.php b/lib/Minz/ExtensionManager.php
new file mode 100644
index 000000000..5880e80f6
--- /dev/null
+++ b/lib/Minz/ExtensionManager.php
@@ -0,0 +1,249 @@
+<?php
+
+/**
+ * An extension manager to load extensions present in EXTENSIONS_PATH.
+ *
+ * @todo see coding style for methods!!
+ */
+class Minz_ExtensionManager {
+	private static $ext_metaname = 'metadata.json';
+	private static $ext_entry_point = 'extension.php';
+	private static $ext_list = array();
+	private static $ext_list_enabled = array();
+
+	private static $ext_auto_enabled = array();
+
+	// List of available hooks. Please keep this list sorted.
+	private static $hook_list = array(
+		'entry_before_display' => array(),  // function($entry) -> Entry | null
+		'entry_before_insert' => array(),  // function($entry) -> Entry | null
+		'feed_before_insert' => array(),  // function($feed) -> Feed | null
+	);
+	private static $ext_to_hooks = array();
+
+	/**
+	 * Initialize the extension manager by loading extensions in EXTENSIONS_PATH.
+	 *
+	 * A valid extension is a directory containing metadata.json and
+	 * extension.php files.
+	 * metadata.json is a JSON structure where the only required fields are
+	 * `name` and `entry_point`.
+	 * extension.php should contain at least a class named <name>Extension where
+	 * <name> must match with the entry point in metadata.json. This class must
+	 * inherit from Minz_Extension class.
+	 */
+	public static function init() {
+		$list_potential_extensions = array_values(array_diff(
+			scandir(EXTENSIONS_PATH),
+			array('..', '.')
+		));
+
+		$system_conf = Minz_Configuration::get('system');
+		self::$ext_auto_enabled = $system_conf->extensions_enabled;
+
+		foreach ($list_potential_extensions as $ext_dir) {
+			$ext_pathname = EXTENSIONS_PATH . '/' . $ext_dir;
+			$metadata_filename = $ext_pathname . '/' . self::$ext_metaname;
+
+			// Try to load metadata file.
+			if (!file_exists($metadata_filename)) {
+				// No metadata file? Invalid!
+				continue;
+			}
+			$meta_raw_content = file_get_contents($metadata_filename);
+			$meta_json = json_decode($meta_raw_content, true);
+			if (!$meta_json || !self::is_valid_metadata($meta_json)) {
+				// metadata.json is not a json file? Invalid!
+				// or metadata.json is invalid (no required information), invalid!
+				Minz_Log::warning('`' . $metadata_filename . '` is not a valid metadata file');
+				continue;
+			}
+
+			$meta_json['path'] = $ext_pathname;
+
+			// Try to load extension itself
+			$extension = self::load($meta_json);
+			if (!is_null($extension)) {
+				self::register($extension);
+			}
+		}
+	}
+
+	/**
+	 * Indicates if the given parameter is a valid metadata array.
+	 *
+	 * Required fields are:
+	 * - `name`: the name of the extension
+	 * - `entry_point`: a class name to load the extension source code
+	 * If the extension class name is `TestExtension`, entry point will be `Test`.
+	 * `entry_point` must be composed of alphanumeric characters.
+	 *
+	 * @param $meta is an array of values.
+	 * @return true if the array is valid, false else.
+	 */
+	public static function is_valid_metadata($meta) {
+		return !(empty($meta['name']) ||
+		         empty($meta['entrypoint']) ||
+		         !ctype_alnum($meta['entrypoint']));
+	}
+
+	/**
+	 * Load the extension source code based on info metadata.
+	 *
+	 * @param $info an array containing information about extension.
+	 * @return an extension inheriting from Minz_Extension.
+	 */
+	public static function load($info) {
+		$entry_point_filename = $info['path'] . '/' . self::$ext_entry_point;
+		$ext_class_name = $info['entrypoint'] . 'Extension';
+
+		include($entry_point_filename);
+
+		// Test if the given extension class exists.
+		if (!class_exists($ext_class_name)) {
+			Minz_Log::warning('`' . $ext_class_name .
+			                  '` cannot be found in `' . $entry_point_filename . '`');
+			return null;
+		}
+
+		// Try to load the class.
+		$extension = null;
+		try {
+			$extension = new $ext_class_name($info);
+		} catch (Minz_ExtensionException $e) {
+			// We cannot load the extension? Invalid!
+			Minz_Log::warning('In `' . $metadata_filename . '`: ' . $e->getMessage());
+			return null;
+		}
+
+		// Test if class is correct.
+		if (!($extension instanceof Minz_Extension)) {
+			Minz_Log::warning('`' . $ext_class_name .
+			                  '` is not an instance of `Minz_Extension`');
+			return null;
+		}
+
+		return $extension;
+	}
+
+	/**
+	 * Add the extension to the list of the known extensions ($ext_list).
+	 *
+	 * If the extension is present in $ext_auto_enabled and if its type is "system",
+	 * it will be enabled in the same time.
+	 *
+	 * @param $ext a valid extension.
+	 */
+	public static function register($ext) {
+		$name = $ext->getName();
+		self::$ext_list[$name] = $ext;
+
+		if ($ext->getType() === 'system' &&
+				in_array($name, self::$ext_auto_enabled)) {
+			self::enable($ext->getName());
+		}
+
+		self::$ext_to_hooks[$name] = array();
+	}
+
+	/**
+	 * Enable an extension so it will be called when necessary.
+	 *
+	 * The extension init() method will be called.
+	 *
+	 * @param $ext_name is the name of a valid extension present in $ext_list.
+	 */
+	public static function enable($ext_name) {
+		if (isset(self::$ext_list[$ext_name])) {
+			$ext = self::$ext_list[$ext_name];
+			self::$ext_list_enabled[$ext_name] = $ext;
+			$ext->enable();
+			$ext->init();
+		}
+	}
+
+	/**
+	 * Enable a list of extensions.
+	 *
+	 * @param $ext_list the names of extensions we want to load.
+	 */
+	public static function enable_by_list($ext_list) {
+		foreach ($ext_list as $ext_name) {
+			self::enable($ext_name);
+		}
+	}
+
+	/**
+	 * Return a list of extensions.
+	 *
+	 * @param $only_enabled if true returns only the enabled extensions (false by default).
+	 * @return an array of extensions.
+	 */
+	public static function list_extensions($only_enabled = false) {
+		if ($only_enabled) {
+			return self::$ext_list_enabled;
+		} else {
+			return self::$ext_list;
+		}
+	}
+
+	/**
+	 * Return an extension by its name.
+	 *
+	 * @param $ext_name the name of the extension.
+	 * @return the corresponding extension or null if it doesn't exist.
+	 */
+	public static function find_extension($ext_name) {
+		if (!isset(self::$ext_list[$ext_name])) {
+			return null;
+		}
+
+		return self::$ext_list[$ext_name];
+	}
+
+	/**
+	 * Add a hook function to a given hook.
+	 *
+	 * The hook name must be a valid one. For the valid list, see self::$hook_list
+	 * array keys.
+	 *
+	 * @param $hook_name the hook name (must exist).
+	 * @param $hook_function the function name to call (must be callable).
+	 * @param $ext the extension which register the hook.
+	 */
+	public static function addHook($hook_name, $hook_function, $ext) {
+		if (isset(self::$hook_list[$hook_name]) && is_callable($hook_function)) {
+			self::$hook_list[$hook_name][] = $hook_function;
+			self::$ext_to_hooks[$ext->getName()][] = $hook_name;
+		}
+	}
+
+	/**
+	 * Call functions related to a given hook.
+	 *
+	 * The hook name must be a valid one. For the valid list, see self::$hook_list
+	 * array keys.
+	 *
+	 * @param $hook_name the hook to call.
+	 * @param additionnal parameters (for signature, please see self::$hook_list comments)
+	 * @todo hook functions will have different signatures. So the $res = func($args);
+	 *       $args = $res; will not work for all of them in the future. We must
+	 *       find a better way to call hooks.
+	 */
+	public static function callHook($hook_name) {
+		$args = func_get_args();
+		unset($args[0]);
+
+		$result = $args[1];
+		foreach (self::$hook_list[$hook_name] as $function) {
+			$result = call_user_func_array($function, $args);
+
+			if (is_null($result)) {
+				break;
+			}
+
+			$args = $result;
+		}
+		return $result;
+	}
+}
diff --git a/lib/Minz/Translate.php b/lib/Minz/Translate.php
index 1b4102ca9..baddcb424 100644
--- a/lib/Minz/Translate.php
+++ b/lib/Minz/Translate.php
@@ -10,9 +10,9 @@
  */
 class Minz_Translate {
 	/**
-	 * $lang_list is the list of available languages.
+	 * $path_list is the list of registered base path to search translations.
 	 */
-	private static $lang_list = array();
+	private static $path_list = array();
 
 	/**
 	 * $lang_name is the name of the current language to use.
@@ -20,9 +20,9 @@ class Minz_Translate {
 	private static $lang_name;
 
 	/**
-	 * $lang_path is the pathname of i18n files (e.g. ./app/i18n/en/).
+	 * $lang_files is a list of registered i18n files.
 	 */
-	private static $lang_path;
+	private static $lang_files = array();
 
 	/**
 	 * $translates is a cache for i18n translation.
@@ -31,13 +31,16 @@ class Minz_Translate {
 
 	/**
 	 * Init the translation object.
-	 * @param $lang_list the list of available languages.
 	 * @param $lang_name the lang to show.
 	 */
-	public static function init($lang_list, $lang_name) {
-		self::$lang_list = $lang_list;
+	public static function init($lang_name = null) {
 		self::$lang_name = $lang_name;
-		self::$lang_path = APP_PATH . '/i18n/' . self::$lang_name . '/';
+		self::$lang_files = array();
+		self::$translates = array();
+		self::registerPath(APP_PATH . '/i18n');
+		foreach (self::$path_list as $path) {
+			self::loadLang($path);
+		}
 	}
 
 	/**
@@ -45,15 +48,103 @@ class Minz_Translate {
 	 * @param $lang_name the new language to use
 	 */
 	public static function reset($lang_name) {
-		self::init(self::$lang_list, $lang_name);
+		self::$lang_name = $lang_name;
+		self::$lang_files = array();
+		self::$translates = array();
+		foreach (self::$path_list as $path) {
+			self::loadLang($path);
+		}
 	}
 
 	/**
 	 * Return the list of available languages.
-	 * @return an array.
+	 * @return an array containing langs found in different registered paths.
 	 */
 	public static function availableLanguages() {
-		return self::$lang_list;
+		$list_langs = array();
+
+		foreach (self::$path_list as $path) {
+			$path_langs = array_values(array_diff(
+				scandir($path),
+				array('..', '.')
+			));
+
+			$list_langs = array_merge($list_langs, $path_langs);
+		}
+
+		return array_unique($list_langs);
+	}
+
+	/**
+	 * Register a new path.
+	 * @param $path a path containing i18n directories (e.g. ./en/, ./fr/).
+	 */
+	public static function registerPath($path) {
+		if (in_array($path, self::$path_list)) {
+			return;
+		}
+
+		self::$path_list[] = $path;
+		self::loadLang($path);
+	}
+
+	/**
+	 * Load translations of the current language from the given path.
+	 * @param $path the path containing i18n directories.
+	 */
+	private static function loadLang($path) {
+		$lang_path = $path . '/' . self::$lang_name;
+		if (!file_exists($lang_path) || is_null(self::$lang_name)) {
+			// The lang path does not exist, nothing more to do.
+			return;
+		}
+
+		$list_i18n_files = array_values(array_diff(
+			scandir($lang_path),
+			array('..', '.')
+		));
+
+		// Each file basename correspond to a top-level i18n key. For each of
+		// these keys we store the file pathname and mark translations must be
+		// reloaded (by setting $translates[$i18n_key] to null).
+		foreach ($list_i18n_files as $i18n_filename) {
+			$i18n_key = basename($i18n_filename, '.php');
+			if (!isset(self::$lang_files[$i18n_key])) {
+				self::$lang_files[$i18n_key] = array();
+			}
+			self::$lang_files[$i18n_key][] = $lang_path . '/' . $i18n_filename;
+			self::$translates[$i18n_key] = null;
+		}
+	}
+
+	/**
+	 * Load the files associated to $key into $translates.
+	 * @param $key the top level i18n key we want to load.
+	 */
+	private static function loadKey($key) {
+		// The top level key is not in $lang_files, it means it does not exist!
+		if (!isset(self::$lang_files[$key])) {
+			Minz_Log::debug($key . ' is not a valid top level key');
+			return false;
+		}
+
+		self::$translates[$key] = array();
+
+		foreach (self::$lang_files[$key] as $lang_pathname) {
+			$i18n_array = include($lang_pathname);
+			if (!is_array($i18n_array)) {
+				Minz_Log::warning('`' . $lang_pathname . '` does not contain a PHP array');
+				continue;
+			}
+
+			// We must avoid to erase previous data so we just override them if
+			// needed.
+			self::$translates[$key] = array_replace_recursive(
+				self::$translates[$key], $i18n_array
+			);
+		}
+
+		return true;
 	}
 
 	/**
@@ -73,16 +164,14 @@ class Minz_Translate {
 			$top_level = array_shift($group);
 		}
 
-		$filename = self::$lang_path . $top_level . '.php';
-
-		// Try to load the i18n file if it's not done yet.
-		if (!isset(self::$translates[$top_level])) {
-			if (!file_exists($filename)) {
-				Minz_Log::debug($top_level . ' is not a valid top level key');
+		// If $translates[$top_level] is null it means we have to load the
+		// corresponding files.
+		if (!isset(self::$translates[$top_level]) ||
+				is_null(self::$translates[$top_level])) {
+			$res = self::loadKey($top_level);
+			if (!$res) {
 				return $key;
 			}
-
-			self::$translates[$top_level] = include($filename);
 		}
 
 		// Go through the i18n keys to get the correct translation value.
diff --git a/lib/Minz/View.php b/lib/Minz/View.php
index 481b0376d..ff5cce4a5 100644
--- a/lib/Minz/View.php
+++ b/lib/Minz/View.php
@@ -13,8 +13,9 @@ class Minz_View {
 	const LAYOUT_FILENAME = '/layout.phtml';
 
 	private $view_filename = '';
-	private $use_layout = null;
+	private $use_layout = true;
 
+	private static $base_pathnames = array(APP_PATH);
 	private static $title = '';
 	private static $styles = array ();
 	private static $scripts = array ();
@@ -37,19 +38,26 @@ class Minz_View {
 	 * Change le fichier de vue en fonction d'un controller / action
 	 */
 	public function change_view($controller_name, $action_name) {
-		$this->view_filename = APP_PATH
-		                     . self::VIEWS_PATH_NAME . '/'
+		$this->view_filename = self::VIEWS_PATH_NAME . '/'
 		                     . $controller_name . '/'
 		                     . $action_name . '.phtml';
 	}
 
 	/**
+	 * Add a base pathname to search views.
+	 *
+	 * New pathnames will be added at the beginning of the list.
+	 *
+	 * @param $base_pathname the new base pathname.
+	 */
+	public static function addBasePathname($base_pathname) {
+		array_unshift(self::$base_pathnames, $base_pathname);
+	}
+
+	/**
 	 * Construit la vue
 	 */
 	public function build () {
-		if ($this->use_layout === null) {	//TODO: avoid file_exists and require views to be explicit
-			$this->use_layout = file_exists (APP_PATH . self::LAYOUT_PATH_NAME . self::LAYOUT_FILENAME);
-		}
 		if ($this->use_layout) {
 			$this->buildLayout ();
 		} else {
@@ -58,21 +66,39 @@ class Minz_View {
 	}
 
 	/**
+	 * Include a view file.
+	 *
+	 * The file is searched inside list of $base_pathnames.
+	 *
+	 * @param $filename the name of the file to include.
+	 * @return true if the file has been included, false else.
+	 */
+	private function includeFile($filename) {
+		// We search the filename in the list of base pathnames. Only the first view
+		// found is considered.
+		foreach (self::$base_pathnames as $base) {
+			$absolute_filename = $base . $filename;
+			if (file_exists($absolute_filename)) {
+				include $absolute_filename;
+				return true;
+			}
+		}
+
+		return false;
+	}
+
+	/**
 	 * Construit le layout
 	 */
 	public function buildLayout () {
-		include (
-			APP_PATH
-			. self::LAYOUT_PATH_NAME
-			. self::LAYOUT_FILENAME
-		);
+		$this->includeFile(self::LAYOUT_PATH_NAME . self::LAYOUT_FILENAME);
 	}
 
 	/**
 	 * Affiche la Vue en elle-même
 	 */
 	public function render () {
-		if ((include($this->view_filename)) === false) {
+		if (!$this->includeFile($this->view_filename)) {
 			Minz_Log::notice('File not found: `' . $this->view_filename . '`');
 		}
 	}
@@ -82,11 +108,8 @@ class Minz_View {
 	 * @param $part l'élément partial à ajouter
 	 */
 	public function partial ($part) {
-		$fic_partial = APP_PATH
-		             . self::LAYOUT_PATH_NAME . '/'
-		             . $part . '.phtml';
-
-		if ((include($fic_partial)) === false) {
+		$fic_partial = self::LAYOUT_PATH_NAME . '/' . $part . '.phtml';
+		if (!$this->includeFile($fic_partial)) {
 			Minz_Log::warning('File not found: `' . $fic_partial . '`');
 		}
 	}
@@ -96,11 +119,8 @@ class Minz_View {
 	 * @param $helper l'élément à afficher
 	 */
 	public function renderHelper ($helper) {
-		$fic_helper = APP_PATH
-		            . '/views/helpers/'
-		            . $helper . '.phtml';
-
-		if ((include($fic_helper)) === false) {;
+		$fic_helper = '/views/helpers/' . $helper . '.phtml';
+		if (!$this->includeFile($fic_helper)) {
 			Minz_Log::warning('File not found: `' . $fic_helper . '`');
 		}
 	}
diff --git a/lib/lib_rss.php b/lib/lib_rss.php
index ffd56eae4..083e87745 100644
--- a/lib/lib_rss.php
+++ b/lib/lib_rss.php
@@ -375,6 +375,7 @@ function recursive_unlink($dir) {
 	if (!is_dir($dir)) {
 		return true;
 	}
+
 	$files = array_diff(scandir($dir), array('.', '..'));
 	foreach ($files as $filename) {
 		$filename = $dir . '/' . $filename;
@@ -385,6 +386,7 @@ function recursive_unlink($dir) {
 			unlink($filename);
 		}
 	}
+
 	return rmdir($dir);
 }
 
@@ -404,3 +406,26 @@ function remove_query_by_get($get, $queries) {
 	}
 	return $final_queries;
 }
+
+
+/**
+ * Add a value in an array and take care it is unique.
+ * @param $array the array in which we add the value.
+ * @param $value the value to add.
+ */
+function array_push_unique(&$array, $value) {
+	$found = array_search($value, $array) !== false;
+	if (!$found) {
+		$array[] = $value;
+	}
+}
+
+
+/**
+ * Remove a value from an array.
+ * @param $array the array from wich value is removed.
+ * @param $value the value to remove.
+ */
+function array_remove(&$array, $value) {
+	$array = array_diff($array, array($value));
+}