Restructure the module lifecycle.

Install: <module>_installer::install() is called, any necessary tables
are created.

Activate: <module>_installer::activate() is called.  Module
controllers are routable, helpers are accessible, etc.  The module is
in use.

Deactivate: <module>_installer::deactivate() is called.  Module code
is not accessible or routable.  Module is *not* in use, but its tables
are still around.

Uninstall: <module>_installer::uninstall() is called.  Module is
completely removed from the database.

Admin > Modules will install and activate modules, but will only
deactivate (will NOT uninstall modules).

9 files changed, 195 insertions, 89 deletions

diff --git a/core/helpers/access.php b/core/helpers/access.php
index b9472aa0..64ce91fa 100644
--- a/core/helpers/access.php
+++ b/core/helpers/access.php
@@ -389,7 +389,9 @@ class access_Core {
    * @return ORM_Iterator
    */
   private static function _get_all_groups() {
-    if (module::is_installed("user")) {
+    // When we build the core package, it's possible that the user module is not installed yet.
+    // This is ok at packaging time, so work around it.
+    if (module::is_active("user")) {
       return ORM::factory("group")->find_all();
     } else {
       return array();
diff --git a/core/helpers/block_manager.php b/core/helpers/block_manager.php
index 9e8ab877..022626e5 100644
--- a/core/helpers/block_manager.php
+++ b/core/helpers/block_manager.php
@@ -41,7 +41,7 @@ class block_manager_Core {
   static function get_available() {
     $blocks = array();
 
-    foreach (module::installed() as $module) {
+    foreach (module::active() as $module) {
       $class_name = "{$module->name}_block";
       if (method_exists($class_name, "get_list")) {
         foreach (call_user_func(array($class_name, "get_list")) as $id => $title) {
diff --git a/core/helpers/core.php b/core/helpers/core.php
index 5023bb15..63f51f86 100644
--- a/core/helpers/core.php
+++ b/core/helpers/core.php
@@ -18,6 +18,10 @@
  * Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA  02110-1301, USA.
  */
 class core_Core {
+  /**
+   * If Gallery is in maintenance mode, then force all non-admins to get routed to a "This site is
+   * down for maintenance" page.
+   */
   static function maintenance_mode() {
     $maintenance_mode = Kohana::config("core.maintenance_mode", false, false);
 
@@ -27,4 +31,22 @@ class core_Core {
       Router::$method = "index";
     }
   }
+
+  /**
+   * This function is called when the Gallery is fully initialized.  We relay it to modules as the
+   * "gallery_ready" event.  Any module that wants to perform an action at the start of every
+   * request should implement the <module>_event::gallery_ready() handler.
+   */
+  static function ready() {
+    module::event("gallery_ready");
+  }
+
+  /**
+   * This function is called right before the Kohana framework shuts down.  We relay it to modules
+   * as the "gallery_shutdown" event.  Any module that wants to perform an action at the start of
+   * every request should implement the <module>_event::gallery_shutdown() handler.
+   */
+  static function shutdown() {
+    module::event("gallery_shutdown");
+  }
 }
\ No newline at end of file
diff --git a/core/helpers/core_installer.php b/core/helpers/core_installer.php
index fc4dc1a6..81246359 100644
--- a/core/helpers/core_installer.php
+++ b/core/helpers/core_installer.php
@@ -41,44 +41,45 @@ class core_installer {
 
       $db->query("CREATE TABLE {graphics_rules} (
                    `id` int(9) NOT NULL auto_increment,
-                   `priority` int(9) NOT NULL,
+                   `active` BOOLEAN default 0,
+                   `args` varchar(255) default NULL,
                    `module_name` varchar(64) NOT NULL,
-                   `target`  varchar(32) NOT NULL,
                    `operation` varchar(64) NOT NULL,
-                   `args` varchar(255) default NULL,
+                   `priority` int(9) NOT NULL,
+                   `target`  varchar(32) NOT NULL,
                    PRIMARY KEY (`id`))
                  ENGINE=InnoDB DEFAULT CHARSET=utf8;");
 
       $db->query("CREATE TABLE {items} (
+                   `id` int(9) NOT NULL auto_increment,
                    `album_cover_item_id` int(9) default NULL,
                    `captured` int(9) default NULL,
                    `created` int(9) default NULL,
                    `description` varchar(2048) default NULL,
                    `height` int(9) default NULL,
-                   `id` int(9) NOT NULL auto_increment,
                    `left` int(9) NOT NULL,
                    `level` int(9) NOT NULL,
                    `mime_type` varchar(64) default NULL,
                    `name` varchar(255) default NULL,
                    `owner_id` int(9) default NULL,
                    `parent_id` int(9) NOT NULL,
+                   `rand_key` float default NULL,
+                   `relative_path_cache` varchar(255) default NULL,
+                   `resize_dirty` boolean default 1,
                    `resize_height` int(9) default NULL,
                    `resize_width` int(9) default NULL,
-                   `resize_dirty` boolean default 1,
                    `right` int(9) NOT NULL,
+                   `sort_column` varchar(64) default NULL,
+                   `sort_order` char(4) default 'ASC',
+                   `thumb_dirty` boolean default 1,
                    `thumb_height` int(9) default NULL,
                    `thumb_width` int(9) default NULL,
-                   `thumb_dirty` boolean default 1,
                    `title` varchar(255) default NULL,
                    `type` varchar(32) NOT NULL,
                    `updated` int(9) default NULL,
                    `view_count` int(9) default 0,
-                   `width` int(9) default NULL,
-                   `rand_key` float default NULL,
-                   `relative_path_cache` varchar(255) default NULL,
-                   `sort_column` varchar(64) default NULL,
-                   `sort_order` char(4) default 'ASC',
                    `weight` int(9) NOT NULL default 0,
+                   `width` int(9) default NULL,
                    PRIMARY KEY (`id`),
                    KEY `parent_id` (`parent_id`),
                    KEY `type` (`type`),
@@ -101,14 +102,15 @@ class core_installer {
       $db->query("CREATE TABLE {messages} (
                    `id` int(9) NOT NULL auto_increment,
                    `key` varchar(255) default NULL,
-                   `value` varchar(255) default NULL,
                    `severity` varchar(32) default NULL,
+                   `value` varchar(255) default NULL,
                    PRIMARY KEY (`id`),
                    UNIQUE KEY(`key`))
                  ENGINE=InnoDB DEFAULT CHARSET=utf8;");
 
       $db->query("CREATE TABLE {modules} (
                    `id` int(9) NOT NULL auto_increment,
+                   `active` BOOLEAN default 0,
                    `name` varchar(64) default NULL,
                    `version` int(9) default NULL,
                    PRIMARY KEY (`id`),
@@ -125,8 +127,8 @@ class core_installer {
 
       $db->query("CREATE TABLE {permissions} (
                    `id` int(9) NOT NULL auto_increment,
-                   `name` varchar(64) default NULL,
                    `display_name` varchar(64) default NULL,
+                   `name` varchar(64) default NULL,
                    PRIMARY KEY (`id`),
                    UNIQUE KEY(`name`))
                  ENGINE=InnoDB DEFAULT CHARSET=utf8;");
@@ -136,8 +138,8 @@ class core_installer {
                    `key` char(32) NOT NULL,
                    `locale` char(10) NOT NULL,
                    `message` text NOT NULL,
-                   `translation` text,
                    `revision` int(9) DEFAULT NULL,
+                   `translation` text,
                    PRIMARY KEY (`id`),
                    UNIQUE KEY(`key`, `locale`),
                    KEY `locale_key` (`locale`, `key`))
@@ -145,11 +147,11 @@ class core_installer {
 
       $db->query("CREATE TABLE {outgoing_translations} (
                    `id` int(9) NOT NULL auto_increment,
+                   `base_revision` int(9) DEFAULT NULL,
                    `key` char(32) NOT NULL,
                    `locale` char(10) NOT NULL,
                    `message` text NOT NULL,
                    `translation` text,
-                   `base_revision` int(9) DEFAULT NULL,
                    PRIMARY KEY (`id`),
                    UNIQUE KEY(`key`, `locale`),
                    KEY `locale_key` (`locale`, `key`))
@@ -157,22 +159,22 @@ class core_installer {
 
       $db->query("CREATE TABLE {sessions} (
                   `session_id` varchar(127) NOT NULL,
-                  `last_activity` int(10) UNSIGNED NOT NULL,
                   `data` text NOT NULL,
+                  `last_activity` int(10) UNSIGNED NOT NULL,
                   PRIMARY KEY (`session_id`))
                  ENGINE=InnoDB DEFAULT CHARSET=utf8;");
 
       $db->query("CREATE TABLE {tasks} (
+                  `id` int(9) NOT NULL auto_increment,
                   `callback` varchar(128) default NULL,
                   `context` text NOT NULL,
                   `done` boolean default 0,
-                  `id` int(9) NOT NULL auto_increment,
-                  `updated` int(9) default NULL,
                   `name` varchar(128) default NULL,
+                  `owner_id` int(9) default NULL,
                   `percent_complete` int(9) default 0,
                   `state` varchar(32) default NULL,
                   `status` varchar(255) default NULL,
-                  `owner_id` int(9) default NULL,
+                  `updated` int(9) default NULL,
                   PRIMARY KEY (`id`),
                   KEY (`owner_id`))
                  ENGINE=InnoDB DEFAULT CHARSET=utf8;");
diff --git a/core/helpers/core_menu.php b/core/helpers/core_menu.php
index f7db2104..eb208560 100644
--- a/core/helpers/core_menu.php
+++ b/core/helpers/core_menu.php
@@ -73,7 +73,7 @@ class core_menu_Core {
                     ->id("admin_menu")
                     ->label(t("Admin")));
       self::admin($admin_menu, $theme);
-      foreach (module::installed() as $module) {
+      foreach (module::active() as $module) {
         if ($module->name == "core") {
           continue;
         }
diff --git a/core/helpers/graphics.php b/core/helpers/graphics.php
index b82b6ba8..6d51e60d 100644
--- a/core/helpers/graphics.php
+++ b/core/helpers/graphics.php
@@ -46,6 +46,7 @@ class graphics_Core {
     $rule->operation = $operation;
     $rule->priority = $priority;
     $rule->args = serialize($args);
+    $rule->active = true;
     $rule->save();
 
     self::mark_dirty($target == "thumb", $target == "resize");
@@ -72,14 +73,33 @@ class graphics_Core {
    * @param string $module_name
    */
   static function remove_rules($module_name) {
-    $db = Database::instance();
-    $status = $db->delete("graphics_rules", array("module_name" => $module_name));
+    $status = Database::instance()->delete("graphics_rules", array("module_name" => $module_name));
     if (count($status)) {
       self::mark_dirty(true, true);
     }
   }
 
   /**
+   * Activate the rules for this module, typically done when the module itself is deactivated.
+   * Note that this does not mark images as dirty so that if you deactivate and reactivate a
+   * module it won't cause all of your images to suddenly require a rebuild.
+   */
+  static function activate_rules($module_name) {
+    Database::instance()
+      ->update("graphics_rules",array("active" => true), array("module_name" => $module_name));
+  }
+
+  /**
+   * Deactivate the rules for this module, typically done when the module itself is deactivated.
+   * Note that this does not mark images as dirty so that if you deactivate and reactivate a
+   * module it won't cause all of your images to suddenly require a rebuild.
+   */
+  static function deactivate_rules($module_name) {
+    Database::instance()
+      ->update("graphics_rules",array("active" => false), array("module_name" => $module_name));
+  }
+
+  /**
    * Rebuild the thumb and resize for the given item.
    * @param Item_Model $item
    */
@@ -106,6 +126,7 @@ class graphics_Core {
       return;
     }
 
+    try {
     foreach ($ops as $target => $output_file) {
       if ($input_item->is_movie()) {
         // Convert the movie to a JPG first
@@ -118,6 +139,7 @@ class graphics_Core {
 
       foreach (ORM::factory("graphics_rule")
                ->where("target", $target)
+                 ->where("active", true)
                ->orderby("priority", "asc")
                ->find_all() as $rule) {
         $args = array($working_file, $output_file, unserialize($rule->args));
@@ -140,6 +162,12 @@ class graphics_Core {
       $item->resize_dirty = 0;
     }
     $item->save();
+    } catch (Kohana_Exception $e) {
+      // Something went wrong rebuilding the image.  Leave it dirty and move on.
+      // @todo we should handle this better.
+      Kohana::log("error", "Caught exception rebuilding image: {$item->title}\n" .
+                  $e->getTraceAsString());
+    }
   }
 
   /**
diff --git a/core/helpers/log.php b/core/helpers/log.php
index cd04e0c5..d0581bf3 100644
--- a/core/helpers/log.php
+++ b/core/helpers/log.php
@@ -80,9 +80,7 @@ class log_Core {
     $log->url = substr(url::abs_current(true), 0, 255);
     $log->referer = request::referrer(null);
     $log->timestamp = time();
-    if (module::is_installed("user")) {
       $log->user_id = user::active()->id;
-    }
     $log->save();
   }
 
diff --git a/core/helpers/module.php b/core/helpers/module.php
index a6fe64b0..539b003c 100644
--- a/core/helpers/module.php
+++ b/core/helpers/module.php
@@ -24,23 +24,20 @@
  * Note: by design, this class does not do any permission checking.
  */
 class module_Core {
-  public static $module_names = array();
+  public static $active = array();
   public static $modules = array();
   public static $var_cache = null;
 
-  static function get_version($module_name) {
-    return ORM::factory("module")->where("name", $module_name)->find()->version;
-  }
-
   /**
    * Set the version of the corresponding Module_Model
    * @param string  $module_name
    * @param integer $version
    */
   static function set_version($module_name, $version) {
-    $module = ORM::factory("module")->where("name", $module_name)->find();
+    $module = self::get($module_name);
     if (!$module->loaded) {
       $module->name = $module_name;
+      $module->active = $module_name == "core";  // only core is active by default
     }
     $module->version = 1;
     $module->save();
@@ -52,25 +49,8 @@ class module_Core {
    * @param string $module_name
    */
   static function get($module_name) {
-    return model_cache::get("module", $module_name, "name");
-  }
-
-  /**
-   * Delete the corresponding Module_Model
-   * @param string $module_name
-   */
-  static function delete($module_name) {
-    $module = ORM::factory("module")->where("name", $module_name)->find();
-    if ($module->loaded) {
-      $db = Database::instance();
-      $db->delete("graphics_rules", array("module_name" => $module->name));
-      $module->delete();
-
-      // We could delete the module vars here too, but it's nice to leave them around in case the
-      // module gets reinstalled.
-
-      Kohana::log("debug", "$module_name: module deleted");
-    }
+    // @todo can't easily use model_cache here because it throw an exception on missing models.
+    return ORM::factory("module", array("name" => $module_name));
   }
 
   /**
@@ -78,27 +58,29 @@ class module_Core {
    * @param string $module_name
    */
   static function is_installed($module_name) {
-    return !empty(self::$module_names[$module_name]);
+    return array_key_exists($module_name, self::$modules);
   }
 
   /**
-   * Return the list of installed modules.
+   * Check to see if a module is active
+   * @param string $module_name
    */
-  static function installed() {
-    return self::$modules;
+  static function is_active($module_name) {
+    return array_key_exists($module_name, self::$modules) &&
+      self::$modules[$module_name]->active;
   }
 
   /**
-   * Return the list of available modules.
+   * Return the list of available modules, including uninstalled modules.
    */
   static function available() {
     $modules = new ArrayObject(array(), ArrayObject::ARRAY_AS_PROPS);
     foreach (array_merge(array("core/module.info"), glob(MODPATH . "*/module.info")) as $file) {
       $module_name = basename(dirname($file));
       $modules->$module_name = new ArrayObject(parse_ini_file($file), ArrayObject::ARRAY_AS_PROPS);
-      $modules->$module_name->installed =
-        empty(self::$modules[$module_name]) ?
-        null : self::$modules[$module_name]->version;
+      $modules->$module_name->installed = self::is_installed($module_name);
+      $modules->$module_name->active = self::is_active($module_name);
+      $modules->$module_name->version = self::get_version($module_name);
       $modules->$module_name->locked = false;
     }
 
@@ -111,35 +93,108 @@ class module_Core {
   }
 
   /**
-   * Install a module.
+   * Return a list of all the active modules in no particular order.
    */
-  static function install($module_name) {
-    $installer_class = "{$module_name}_installer";
-    Kohana::log("debug", "$installer_class install (initial)");
-    if ($module_name != "core") {
-      require_once(DOCROOT . "modules/${module_name}/helpers/{$installer_class}.php");
+  static function active() {
+    return self::$active;
     }
+
+  /**
+   * Install a module.  This will call <module>_installer::install(), which is responsible for
+   * creating database tables, setting module variables and and calling module::set_version().
+   * Note that after installing, the module must be activated before it is available for use.
+   * @param string $module_name
+   */
+  static function install($module_name) {
     $kohana_modules = Kohana::config("core.modules");
     $kohana_modules[] = MODPATH . $module_name;
     Kohana::config_set("core.modules",  $kohana_modules);
 
+    $installer_class = "{$module_name}_installer";
     if (method_exists($installer_class, "install")) {
       call_user_func_array(array($installer_class, "install"), array());
     }
 
-    self::load_modules();
+    // Now the module is installed but inactive, so don't leave it in the active path
+    array_pop($kohana_modules);
+    Kohana::config_set("core.modules",  $kohana_modules);
+
     log::success(
       "module", t("Installed module %module_name", array("module_name" => $module_name)));
   }
 
   /**
-   * Uninstall a module.
+   * Activate an installed module.  This will call <module>_installer::activate() which should take
+   * any steps to make sure that the module is ready for use.  This will also activate any
+   * existing graphics rules for this module.
+   * @param string $module_name
+   */
+  static function activate($module_name) {
+    $kohana_modules = Kohana::config("core.modules");
+    $kohana_modules[] = MODPATH . $module_name;
+    Kohana::config_set("core.modules",  $kohana_modules);
+
+    $installer_class = "{$module_name}_installer";
+    if (method_exists($installer_class, "activate")) {
+      call_user_func_array(array($installer_class, "activate"), array());
+    }
+
+    $module = self::get($module_name);
+    if ($module->loaded) {
+      $module->active = true;
+      $module->save();
+    }
+
+    self::load_modules();
+    graphics::activate_rules($module_name);
+    log::success(
+      "module", t("Activated module %module_name", array("module_name" => $module_name)));
+  }
+
+  /**
+   * Deactivate an installed module.  This will call <module>_installer::deactivate() which
+   * should take any cleanup steps to make sure that the module isn't visible in any way.
+   * @param string $module_name
+   */
+  static function deactivate($module_name) {
+    $installer_class = "{$module_name}_installer";
+    if (method_exists($installer_class, "deactivate")) {
+      call_user_func_array(array($installer_class, "deactivate"), array());
+    }
 
+    $module = self::get($module_name);
+    if ($module->loaded) {
+      $module->active = false;
+      $module->save();
+    }
+
+    self::load_modules();
+    graphics::deactivate_rules($module_name);
+    log::success(
+      "module", t("Deactivated module %module_name", array("module_name" => $module_name)));
+  }
+
+  /**
+   * Uninstall a deactivated module.  This will call <module>_installer::uninstall() which should
+   * take whatever steps necessary to make sure that all traces of a module are gone.
+   * @param string $module_name
    */
   static function uninstall($module_name) {
     $installer_class = "{$module_name}_installer";
-    Kohana::log("debug", "$installer_class uninstall");
+    if (method_exists($installer_class, "uninstall")) {
     call_user_func(array($installer_class, "uninstall"));
+    }
+
+    graphics::remove_rule($module_name);
+    $module = self::get($module_name);
+    if ($module->loaded) {
+      $module->delete();
+    }
+
+    // We could delete the module vars here too, but it's nice to leave them around
+    // in case the module gets reinstalled.
+
+    self::load_modules();
     log::success(
       "module", t("Uninstalled module %module_name", array("module_name" => $module_name)));
   }
@@ -153,19 +208,18 @@ class module_Core {
     $kohana_modules = $core["modules"];
     $modules = ORM::factory("module")->find_all();
 
+    self::$modules = array();
+    self::$active = array();
     foreach ($modules as $module) {
-      self::$module_names[$module->name] = $module->name;
       self::$modules[$module->name] = $module;
-
-      // @todo For some reason if we don't load the core module here, the test framework fails.
-      // This requires some investigation.
+      if ($module->active) {
+        self::$active[] = $module;
+      }
       if ($module->name != "core") {
         $kohana_modules[] = MODPATH . $module->name;
       }
     }
     Kohana::config_set("core.modules", $kohana_modules);
-
-    self::event("gallery_ready");
   }
 
   /**
@@ -178,7 +232,11 @@ class module_Core {
     array_shift($args);
     $function = str_replace(".", "_", $name);
 
-    foreach (self::installed() as $module) {
+    foreach (self::$modules as $module) {
+      if (!$module->active) {
+        continue;
+      }
+
       $class = "{$module->name}_event";
       if (method_exists($class, $function)) {
         call_user_func_array(array($class, $function), $args);
@@ -187,17 +245,6 @@ class module_Core {
   }
 
   /**
-   * Kohana shutdown event handler
-   * @param string $module_name
-   * @param string $name
-   * @param string $default_value
-   * @return the value
-   */
-  static function shutdown() {
-    self::event("gallery_shutdown");
-  }
-
-  /**
    * Get a variable from this module
    * @param string $module_name
    * @param string $name
@@ -256,7 +303,6 @@ class module_Core {
       ->where("name", $name)
       ->find();
     if (!$var->loaded) {
-      $var = ORM::factory("var");
       $var->module_name = $module_name;
       $var->name = $name;
     }
@@ -300,4 +346,12 @@ class module_Core {
     Database::instance()->delete("vars", array("module_name" => "core", "name" => "_cache"));
     self::$var_cache = null;
   }
+
+  /**
+   * Return the version of the installed module.
+   * @param string $module_name
+   */
+  static function get_version($module_name) {
+    return self::get($module_name)->version;
+  }
 }
diff --git a/core/helpers/task.php b/core/helpers/task.php
index 1bc2996a..a8a004ab 100644
--- a/core/helpers/task.php
+++ b/core/helpers/task.php
@@ -23,8 +23,8 @@ class task_Core {
    */
   static function get_definitions() {
     $tasks = array();
-    foreach (module::installed() as $module_name => $module_info) {
-      $class_name = "{$module_name}_task";
+    foreach (module::active() as $module) {
+      $class_name = "{$module->name}_task";
       if (method_exists($class_name, "available_tasks")) {
         foreach (call_user_func(array($class_name, "available_tasks")) as $task) {
           $tasks[$task->callback] = $task;