Fixes #1986, #2170, #2225, #2759. Integrated ElggPluginPackage and ElggPluginManifest with ElggPlugin. System now uses ElggPlugin objects to determin plugins. Order is stored in private settings. This absolutely requires running upgrade.php.

git-svn-id: http://code.elgg.org/elgg/trunk@7817 36083f99-b078-4883-b0ff-0f9b5a30f544

4 files changed, 828 insertions, 29 deletions

diff --git a/engine/classes/ElggPlugin.php b/engine/classes/ElggPlugin.php
index 887eb667f..fb9138ab9 100644
--- a/engine/classes/ElggPlugin.php
+++ b/engine/classes/ElggPlugin.php
@@ -9,6 +9,11 @@
  * @subpackage Plugins.Settings
  */
 class ElggPlugin extends ElggObject {
+	public $package;
+	public $manifest;
+
+	private $path;
+	private $pluginID;
 
 	/**
 	 * Set subtype to 'plugin'
@@ -19,10 +24,704 @@ class ElggPlugin extends ElggObject {
 		parent::initializeAttributes();
 
 		$this->attributes['subtype'] = "plugin";
+
+		// plugins must be public.
+		$this->access_id = ACCESS_PUBLIC;
+	}
+
+
+	/**
+	 * Loads the plugin by GUID or path.
+	 *
+	 * @warning Unlike other ElggEntity objects, you cannot null instantiate
+	 *          ElggPlugin. You must point it to an actual plugin GUID or location.
+	 *
+	 * @param mixed $plugin The GUID of the ElggPlugin object or the path of
+	 *                      the plugin to load.
+	 */
+	public function __construct($plugin) {
+		if (!$plugin) {
+			throw new PluginException(elgg_echo('PluginException:NullInstantiated'));
+		}
+
+		// ElggEntity can be instantiated with a guid or an object.
+		// @todo plugins w/id 12345
+		if (is_numeric($plugin) || is_object($plugin)) {
+			parent::__construct($plugin);
+			$this->path = get_config('plugins_path') . $this->getID();
+		} else {
+			// not a full path, so assume an id
+			// use the default path
+			if (substr($plugin, 0, 1) != '/') {
+				$plugin = elgg_get_plugin_path() . $plugin;
+			}
+
+			// path checking is done in the package
+			$plugin = sanitise_filepath($plugin);
+			$this->path = $plugin;
+			$path_parts = explode('/', rtrim($plugin, '/'));
+			$plugin_id = array_pop($path_parts);
+			$this->pluginID = $plugin_id;
+
+			// check if we're loading an existing plugin
+			$existing_plugin = elgg_get_plugin_from_id($this->pluginID);
+			$existing_guid = null;
+
+			if ($existing_plugin) {
+				$existing_guid = $existing_plugin->guid;
+			}
+
+			// load the rest of the plugin
+			parent::__construct($existing_guid);
+		}
+
+		// We have to let the entity load so we can manipulate it with the API.
+		// If the path is wrong or would cause an exception, catch it,
+		// disable the plugin, and emit an error.
+		try {
+			$this->package = new ElggPluginPackage($this->path, false);
+			$this->manifest = $this->package->getManifest();
+		} catch (Exception $e) {
+			// we always have to allow the entity to load.
+		}
+	}
+
+
+	/**
+	 * Save the plugin object.  Make sure required values exist.
+	 *
+	 * @see ElggObject::save()
+	 * @return bool
+	 */
+	public function save() {
+		// own by the current site so users can be deleted without affecting plugins
+		$site = get_config('site');
+		$this->attributes['site_guid'] = $site->guid;
+		$this->attributes['owner_guid'] = $site->guid;
+		$this->attributes['container_guid'] = $site->guid;
+		$this->attributes['title'] = $this->pluginID;
+
+		if (parent::save()) {
+			// make sure we have a priority
+			$priority = $this->getPriority();
+			if ($priority === FALSE || $priority === NULL) {
+				return $this->setPriority('last');
+			}
+		} else {
+			return false;
+		}
+	}
+
+
+	// Plugin ID
+
+	/**
+	 * Returns the ID (dir name) of this plugin
+	 *
+	 * @return string
+	 */
+	public function getID() {
+		return $this->title;
+	}
+
+
+	/**
+	 * Sets the location of this plugin.
+	 *
+	 * @param path $id The path to the plugin's dir.
+	 * @return bool
+	 */
+	public function setID($id) {
+		return $this->attributes['title'] = $id;
+	}
+
+
+	// Load Priority
+
+	/**
+	 * Gets the plugin's load priority.
+	 *
+	 * @return int
+	 */
+	public function getPriority() {
+		$name = elgg_namespace_plugin_private_setting('internal', 'priority');
+		return $this->$name;
+	}
+
+
+	/**
+	 * Sets the priority of the plugin
+	 *
+	 * @param mixed $priority  The priority to set. One of +1, -1, first, last, or a number.
+	 *                         If given a number, this will displace all plugins at that number
+	 *                         and set their priorities +1
+	 * @param mixed $site_guid Optional site GUID.
+	 * @return bool
+	 */
+	public function setPriority($priority, $site_guid = null) {
+		if (!$this->guid) {
+			return false;
+		}
+
+		$db_prefix = get_config('dbprefix');
+		$name = elgg_namespace_plugin_private_setting('internal', 'priority');
+		// if no priority assume a priority of 0
+		$old_priority = (int) $this->getPriority();
+		$max_priority = elgg_get_max_plugin_priority();
+
+		if ($priority == $old_priority) {
+			return false;
+		}
+
+		// there's nothing above the max.
+		if ($priority > $max_priority) {
+			$priority = $max_priority;
+		}
+
+		// there's nothing below 1.
+		if ($priority < 1) {
+			$priority = 1;
+		}
+
+		// (int) 0 matches (string) first, so cast to string.
+		$priority = (string) $priority;
+
+		switch ($priority) {
+			case '+1':
+				$priority = $old_priority + 1;
+				break;
+
+			case '-1':
+				$priority = $old_priority - 1;
+				break;
+
+			case 'first':
+				$priority = 1;
+				break;
+
+			case 'last':
+				$priority = $max_priority;
+				break;
+		}
+
+		// should be a number by now
+		if ($priority) {
+			if (!is_numeric($priority)) {
+				return false;
+			}
+
+			if ($priority > $old_priority) {
+				$op = '-';
+				$where = "CAST(value as unsigned) BETWEEN $old_priority AND $priority";
+			} else {
+				$op = '+';
+				$where = "CAST(value as unsigned) BETWEEN $priority AND $old_priority";
+			}
+
+			// displace the ones affected by this change
+			$q = "UPDATE {$db_prefix}private_settings
+				SET value = CAST(value as unsigned) $op 1
+				WHERE entity_guid != $this->guid
+				AND name = '$name'
+				AND $where";
+
+			if (!update_data($q)) {
+				return false;
+			}
+
+			// set this priority
+			if ($this->set($name, $priority)) {
+				//return elgg_plugins_reindex_priorities();
+				return true;
+			} else {
+				return false;
+			}
+		}
+
+		return false;
+	}
+
+
+	// Plugin settings
+
+	/**
+	 * Returns a plugin setting
+	 *
+	 * @todo These need to be namespaced
+	 *
+	 * @param string $name The setting name
+	 * @return mixed
+	 */
+	public function getSetting($name) {
+		return $this->$name;
+	}
+
+
+	/**
+	 * Set a plugin setting for the plugin
+	 *
+	 * @todo This will only work once the plugin has a GUID.
+	 * @todo These need to be namespaced.
+	 *
+	 * @param string $name  The name to set
+	 * @param string $value The value to set
+	 *
+	 * @return bool
+	 */
+	public function setSetting($name, $value) {
+		if ($this->guid) {
+			return false;
+		}
+		// Hook to validate setting
+		$value = elgg_trigger_plugin_hook('plugin:setting', 'plugin', array(
+			'plugin' => $this->pluginID,
+			'plugin_object' => $this,
+			'name' => $name,
+			'value' => $value
+		), $value);
+
+		return $this->$name = $value;
 	}
 
 
 	/**
+	 * Removes a plugin setting name and value.
+	 *
+	 * @param string $name The setting name to remove
+	 *
+	 * @return bool
+	 */
+	public function removeSetting($name) {
+		return remove_private_setting($this->guid, $name);
+	}
+
+
+	/**
+	 * Removes all settings for this plugin.
+	 *
+	 * @todo Should be a better way to do this without dropping to raw SQL.
+	 * @todo If we could namespace the plugin settings this would be cleaner.
+	 * @return bool
+	 */
+	public function removeAllSettings() {
+		$db_prefix = get_config('dbprefix');
+		$ps_prefix = elgg_namespace_plugin_private_setting('setting', '');
+
+		$q = "DELETE FROM {$db_prefix}private_settings
+			WHERE entity_guid = $this->guid
+			AND name NOT LIKE '$ps_prefix%'";
+
+		return delete_data($q);
+	}
+
+
+	// User settings
+
+	/**
+	 * Returns a user's setting for this plugin
+	 *
+	 * @param int    $user_guid The user GUID
+	 * @param string $name      The setting name
+	 *
+	 * @return mixed The setting string value or false
+	 */
+	public function getUserSetting($user_guid, $name) {
+		$name = elgg_namespace_plugin_private_setting('user_setting', $name, $this->getID());
+		return get_private_setting($user_guid, $name);
+	}
+
+	/**
+	 * Sets a user setting for a plugin
+	 *
+	 * @param int    $user_guid The user GUID
+	 * @param string $name      The setting name
+	 * @param string $value     The setting value
+	 *
+	 * @return mixed The new setting ID or false
+	 */
+	public function setUserSetting($user_guid, $name, $value) {
+		$name = elgg_namespace_plugin_private_setting('user_setting', $name, $this->getID());
+		return set_private_setting($user_guid, $name, $value);
+	}
+
+
+	/**
+	 * Removes a user setting name and value.
+	 *
+	 * @param int    $user_guid The user GUID
+	 * @param string $name      The user setting name
+	 *
+	 * @return bool
+	 */
+	public function removeUserSetting($user_guid, $name) {
+		$name = elgg_namespace_plugin_private_setting('user_setting', $name, $this->getID());
+		return remove_private_setting($user_guid, $name);
+	}
+
+
+	/**
+	 * Removes all User Settings for this plugin
+	 *
+	 * Use {@link removeAllUsersSettings()} to remove all user
+	 * settings for all users.  (Note the plural 'Users'.)
+	 *
+	 * @param int $user_guid The user GUID to remove user settings.
+	 * @return bool
+	 */
+	public function removeAllUserSettings($user_guid) {
+		$db_prefix = get_config('dbprefix');
+		$ps_prefix = elgg_namespace_plugin_private_setting('user_setting', '', $this->getID());
+
+		$q = "DELETE FROM {$db_prefix}private_settings
+			WHERE entity_guid = $user_guid
+			AND name LIKE '$ps_prefix%'";
+
+		return delete_data($q);
+	}
+
+
+	/**
+	 * Removes this plugin's user settings for all users.
+	 *
+	 * Use {@link removeAllUserSettings()} if you just want to remove
+	 * settings for a single user.
+	 *
+	 * @return bool
+	 */
+	public function removeAllUsersSettings() {
+		$db_prefix = get_config('dbprefix');
+		$ps_prefix = elgg_namespace_plugin_private_setting('user_setting', '', $this->getID());
+
+		$q = "DELETE FROM {$db_prefix}private_settings
+			WHERE name LIKE '$ps_prefix%'";
+
+		return delete_data($q);
+	}
+
+
+	// validation
+
+	/**
+	 * Returns if the plugin is complete, meaning has all required files
+	 * and Elgg can read them and they make sense.
+	 *
+	 * @todo bad name? This could be confused with isValid() from ElggPackage.
+	 *
+	 * @return bool
+	 */
+	public function isValid() {
+		if (!$this->getID()) {
+			return false;
+		}
+
+		if (!$this->package instanceof ElggPluginPackage) {
+			return false;
+		}
+
+		if (!$this->package->isValid()) {
+			return false;
+		}
+
+		return true;
+	}
+
+
+	/**
+	 * Is this plugin active?
+	 *
+	 * @param int $site_guid Optional site guid.
+	 * @return bool
+	 */
+	public function isActive($site_guid = null) {
+		if (!$this->guid) {
+			return false;
+		}
+
+		if ($site_guid) {
+			$site = get_entity($site_guid);
+
+			if (!($site instanceof ElggSite)) {
+				return false;
+			}
+		} else {
+			$site = get_config('site');
+		}
+
+		return check_entity_relationship($this->guid, 'active_plugin', $site->guid);
+	}
+
+
+	/**
+	 * Checks if this plugin can be activated on the current
+	 * Elgg installation.
+	 *
+	 * @param mixed $site_guid Optional site guid
+	 * @return bool
+	 */
+	public function canActivate($site_guid = null) {
+		if ($this->package) {
+			return $this->package->isValid() && $this->package->checkDependencies();
+		}
+
+		return false;
+	}
+
+
+	// activating and deactivating
+
+	/**
+	 * Actives the plugin for the current site.
+	 *
+	 * @param mixed $site_guid Optional site GUID.
+	 * @return bool
+	 */
+	public function activate($site_guid = null) {
+		if ($this->isActive($site_guid)) {
+			return false;
+		}
+		// set in the db, now perform tasks and emit events
+		if ($this->setStatus(true, $site_guid)) {
+			// emit an event. returning false will make this not be activated.
+			// we need to do this after it's been fully activated
+			// or the deactivate will be confused.
+			$params = array(
+				'plugin_id' => $this->pluginID,
+				'plugin_entity' => $this
+			);
+
+			$return = elgg_trigger_event('activate', 'plugin', $params);
+
+			// if there are any on_enable functions, start the plugin now and run them
+			// Note: this will not run re-run the init hooks!
+			$functions = $this->manifest->getOnActivate();
+			if ($return && $functions) {
+				$flags = ELGG_PLUGIN_INCLUDE_START | ELGG_PLUGIN_REGISTER_CLASSES
+						| ELGG_PLUGIN_REGISTER_LANGUAGES | ELGG_PLUGIN_REGISTER_VIEWS;
+
+				$this->start($flags);
+				foreach ($functions as $function) {
+					if (!is_callable($function)) {
+						$return = false;
+					} else {
+						$on_enable = call_user_func($function);
+						// allow null to mean "I don't care" like other subsystems
+						$return = ($on_disable === false) ? false: true;
+					}
+
+					if ($return === false) {
+						break;
+					}
+				}
+			}
+
+			if ($return === false) {
+				$this->deactivate($site_guid);
+			}
+
+			return $return;
+		}
+
+		return false;
+	}
+
+
+	/**
+	 * Deactivates the plugin.
+	 *
+	 * @param mixed $site_guid Optional site GUID.
+	 * @return bool
+	 */
+	public function deactivate($site_guid = null) {
+		if (!$this->isActive($site_guid)) {
+			return false;
+		}
+
+		// emit an event. returning false will cause this to not be deactivated.
+		$params = array(
+			'plugin_id' => $this->pluginID,
+			'plugin_entity' => $this
+		);
+
+		$return = elgg_trigger_event('deactivate', 'plugin', $params);
+
+		// run any deactivate functions
+		// check for the manifest in case we haven't fully loaded the plugin.
+		if ($this->manifest) {
+			$functions = $this->manifest->getOnDeactivate();
+		} else {
+			$functions = array();
+		}
+
+		if ($return && $functions) {
+			foreach ($functions as $function) {
+				if (!is_callable($function)) {
+					$return = false;
+				} else {
+					$on_enable = call_user_func($function);
+					// allow null to mean "I don't care" like other subsystems
+					$return = ($on_disable === false) ? false : true;
+				}
+
+				if ($return === false) {
+					break;
+				}
+			}
+		}
+
+		if ($return === false) {
+			return false;
+		} else {
+			return $this->setStatus(false, $site_guid);
+		}
+	}
+
+
+	/**
+	 * Start the plugin.
+	 *
+	 * @param int $flags Start flags for the plugin. See the constants in lib/plugins.php for details.
+	 * @return true
+	 * @throws PluginException
+	 */
+	public function start($flags) {
+		if (!$this->canActivate()) {
+			return false;
+		}
+
+		// include start file
+		if ($flags & ELGG_PLUGIN_INCLUDE_START) {
+			$this->includeStart();
+		}
+
+		// include views
+		if ($flags & ELGG_PLUGIN_REGISTER_VIEWS) {
+			$this->registerViews();
+		}
+
+		// include languages
+		if ($flags & ELGG_PLUGIN_REGISTER_LANGUAGES) {
+			$this->registerLanguages();
+		}
+
+		// include classes
+		if ($flags & ELGG_PLUGIN_REGISTER_CLASSES) {
+			$this->registerClasses();
+		}
+
+		return true;
+	}
+
+
+	// start helpers
+
+	/**
+	 * Includes the plugin's start file
+	 *
+	 * @throws PluginException
+	 * @return true
+	 */
+	protected function includeStart() {
+		$start = "$this->path/start.php";
+		if (!include($start)) {
+			$msg = elgg_echo('ElggPlugin:Exception:CannotIncludeStart',
+							array($this->getID(), $this->guid, $this->path));
+			throw new PluginException($msg);
+		}
+
+		return true;
+	}
+
+	/**
+	 * Registers the plugin's views
+	 *
+	 * @throws PluginException
+	 * @return true
+	 */
+	protected function registerViews() {
+		$view_dir = "$this->path/views/";
+
+		// plugins don't have to have views.
+		if (!is_dir($view_dir)) {
+			return true;
+		}
+
+		// but if they do, they have to be readable
+		$handle = opendir($view_dir);
+		if (!$handle) {
+			$msg = elgg_echo('ElggPlugin:Exception:CannotRegisterViews',
+							array($this->getID(), $this->guid, $view_dir));
+			throw new PluginException($msg);
+		}
+
+		while (FALSE !== ($view_type = readdir($handle))) {
+			$view_type_dir = $view_dir . $view_type;
+
+			if ('.' !== substr($view_type, 0, 1) && is_dir($view_type_dir)) {
+				if (autoregister_views('', $view_type_dir, $view_dir, $view_type)) {
+					elgg_register_viewtype($view_type);
+				} else {
+					$msg = elgg_echo('ElggPlugin:Exception:CannotRegisterViews',
+									array($this->getID(), $view_type_dir));
+					throw new PluginException($msg);
+				}
+			}
+		}
+
+		return true;
+	}
+
+	/**
+	 * Registers the plugin's languages
+	 *
+	 * @throws PluginException
+	 * @return true
+	 */
+	protected function registerLanguages() {
+		$languages_path = "$this->path/languages";
+
+		// don't need to have classes
+		if (!is_dir($languages_path)) {
+			return true;
+		}
+
+		// but need to have working ones.
+		if (!register_translations($languages_path)) {
+			$msg = elgg_echo('ElggPlugin:Exception:CannotRegisterLanguages',
+							array($this->getID(), $this->guid, $languages_path));
+			throw new PluginException($msg);
+		}
+
+		return true;
+	}
+
+	/**
+	 * Registers the plugin's classes
+	 *
+	 * @throws PluginException
+	 * @return true
+	 */
+	protected function registerClasses() {
+		$classes_path = "$this->path/classes";
+
+		// don't need to have classes
+		if (!is_dir($classes_path)) {
+			return true;
+		}
+
+		// but need to have working ones.
+		if (!elgg_register_classes($classes_path)) {
+			$msg = elgg_echo('ElggPlugin:Exception:CannotRegisterClasses',
+							array($this->getID(), $this->guid, $classes_path));
+			throw new PluginException($msg);
+		}
+
+		return true;
+	}
+
+
+	// generic helpers and overrides
+
+	/**
 	 * Get a value from private settings.
 	 *
 	 * @param string $name Name
@@ -30,8 +729,16 @@ class ElggPlugin extends ElggObject {
 	 * @return mixed
 	 */
 	public function get($name) {
+		// rewrite for old and inaccurate plugin:setting
+		if (strstr($name, 'plugin:setting:')) {
+			$msg = 'Direct access of user settings is deprecated. Use ElggPlugin->getUserSetting()';
+			elgg_deprecated_notice($msg, 1.8);
+			$name = str_replace('plugin:setting:', '', $name);
+			$name = elgg_namespace_plugin_private_setting('user_setting', $name);
+		}
+
 		// See if its in our base attribute
-		if (isset($this->attributes[$name])) {
+		if (array_key_exists($name, $this->attributes)) {
 			return $this->attributes[$name];
 		}
 
@@ -69,4 +776,34 @@ class ElggPlugin extends ElggObject {
 
 		return true;
 	}
+
+	/**
+	 * Sets the plugin to active or inactive for $site_guid.
+	 *
+	 * @param bool  $active    Set to active or inactive
+	 * @param mixed $site_guid Int for specific site, null for current site.
+	 *
+	 * @return bool
+	 */
+	private function setStatus($active, $site_guid = null) {
+		if (!$this->guid) {
+			return false;
+		}
+
+		if ($site_guid) {
+			$site = get_entity($site_guid);
+
+			if (!($site instanceof ElggSite)) {
+				return false;
+			}
+		} else {
+			$site = get_config('site');
+		}
+
+		if ($active) {
+			return add_entity_relationship($this->guid, 'active_plugin', $site->guid);
+		} else {
+			return remove_entity_relationship($this->guid, 'active_plugin', $site->guid);
+		}
+	}
 }
\ No newline at end of file
diff --git a/engine/classes/ElggPluginManifest.php b/engine/classes/ElggPluginManifest.php
index 801769eb9..9fcdaaf55 100644
--- a/engine/classes/ElggPluginManifest.php
+++ b/engine/classes/ElggPluginManifest.php
@@ -481,6 +481,77 @@ class ElggPluginManifest {
 	}
 
 	/**
+	 * Returns the functions to run upon activation
+	 *
+	 *  @return array
+	 */
+	public function getOnActivate() {
+		$functions = $this->parser->getAttribute('on_activate');
+
+		if (!$functions) {
+			$functions = array();
+		}
+
+		return $functions;
+	}
+
+	/**
+	 * Returns the functions to run upon deactivation
+	 *
+	 *  @return array
+	 */
+	public function getOnDeactivate() {
+		$functions = $this->parser->getAttribute('on_deactivate');
+
+		if (!$functions) {
+			$functions = array();
+		}
+
+		return $functions;
+	}
+
+	/**
+	 * Returns the admin interface to use.
+	 *
+	 *  @return string simple or advanced
+	 */
+	public function getAdminInterface() {
+		$interface = $this->parser->getAttribute('admin_interface');
+
+		switch ($interface) {
+			case 'simple':
+			case 'advanced':
+				return $interface;
+
+			default:
+				return 'advanced';
+		}
+	}
+
+	/**
+	 * Returns the admin interface to use.
+	 *
+	 *  @return bool
+	 */
+	public function getActivateOnInstall() {
+		$activate = $this->parser->getAttribute('activate_on_install');
+		switch (strtolower($activate)) {
+			case 'yes':
+			case 'true':
+			case 'on':
+			case 1:
+				return true;
+
+			case 'no':
+			case 'false':
+			case 'off':
+			case 0:
+			case '':
+				return false;
+		}
+	}
+
+	/**
 	 * Normalizes an array into the structure specified
 	 *
 	 * @param array $struct The struct to normalize $element to.
diff --git a/engine/classes/ElggPluginManifestParser18.php b/engine/classes/ElggPluginManifestParser18.php
index 9a4cfb2b7..1f5b51bb5 100644
--- a/engine/classes/ElggPluginManifestParser18.php
+++ b/engine/classes/ElggPluginManifestParser18.php
@@ -15,7 +15,8 @@ class ElggPluginManifestParser18 extends ElggPluginManifestParser {
 	protected $validAttributes = array(
 		'name', 'author', 'version', 'blurb', 'description',
 		'website', 'copyright', 'license', 'requires', 'screenshot',
-		'category', 'conflicts', 'provides', 'admin'
+		'category', 'conflicts', 'provides', 'on_activate', 'on_deactivate',
+		'admin_interface', 'activate_on_install'
 	);
 
 	/**
@@ -45,26 +46,19 @@ class ElggPluginManifestParser18 extends ElggPluginManifestParser {
 				case 'website':
 				case 'copyright':
 				case 'license':
+				case 'admin_interface':
+				case 'activate_on_install':
 					$parsed[$element->name] = $element->content;
 					break;
 
 				// arrays
+				case 'on_activate':
+				case 'on_deactivate':
 				case 'category':
-					$parsed['category'][] = $element->content;
-					break;
-
-				case 'admin':
-					$parsed['admin'] = array();
-					if (!isset($element->children)) {
-						return false;
-					}
-
-					foreach ($element->children as $child_element) {
-						$parsed['admin'][$child_element->name] = $child_element->content;
-					}
-
+					$parsed[$element->name][] = $element->content;
 					break;
 
+				// 3d arrays
 				case 'screenshot':
 				case 'provides':
 				case 'conflicts':
diff --git a/engine/classes/ElggPluginPackage.php b/engine/classes/ElggPluginPackage.php
index 8bbacce22..6301ad1f2 100644
--- a/engine/classes/ElggPluginPackage.php
+++ b/engine/classes/ElggPluginPackage.php
@@ -239,16 +239,6 @@ class ElggPluginPackage {
 		return true;
 	}
 
-	/**
-	 * Checks if this plugin can be activated on the current
-	 * Elgg installation.
-	 *
-	 * @return bool
-	 */
-	public function canActivate() {
-		return $this->checkDependencies();
-	}
-
 
 	/************
 	 * Manifest *
@@ -261,7 +251,9 @@ class ElggPluginPackage {
 	 */
 	public function getManifest() {
 		if (!$this->manifest) {
-			$this->loadManifest();
+			if (!$this->loadManifest()) {
+				return false;
+			}
 		}
 
 		return $this->manifest;
@@ -275,9 +267,14 @@ class ElggPluginPackage {
 	 */
 	private function loadManifest() {
 		$file = $this->path . 'manifest.xml';
-		$this->manifest = new ElggPluginManifest($file, $this->id);
 
-		if ($this->manifest) {
+		try {
+			$this->manifest = new ElggPluginManifest($file, $this->id);
+		} catch (Exception $e) {
+			return false;
+		}
+
+		if ($this->manifest instanceof ElggPluginManifest) {
 			return true;
 		}
 
@@ -307,7 +304,7 @@ class ElggPluginPackage {
 	public function checkDependencies($full_report = false) {
 		$requires = $this->getManifest()->getRequires();
 		$conflicts = $this->getManifest()->getConflicts();
-		$enabled_plugins = get_installed_plugins('enabled');
+		$enabled_plugins = elgg_get_plugins('active');
 		$report = array();
 
 		foreach (array('requires', 'conflicts') as $dep_type) {