From d59c6ed4f149c201542c8b38f9ad9d61b4daabf4 Mon Sep 17 00:00:00 2001
From: Tim Almdal <tnalmdal@shaw.ca>
Date: Thu, 21 Jan 2010 12:57:45 -0800
Subject: The admin module controller allows modules to provide a
 check_environment method which is called prior to installation.  The method
 allows the module to provide an error message or warnings if the module can
 not be installed or activated without issues.  The admin module controller
 also will fire a pre_deactivate event, which allows modules to indicate
 issues that may arise be deactivating the specified module.

These messages are displayed in a dialog box prior to installation in order to
allow the gallery administrator to determine the appropriate action before proceeding.

Lays the foundation for implementing a fix for ticket #937
---
 modules/gallery/helpers/module.php | 65 +++++++++++++++++++++++++++++++-------
 1 file changed, 53 insertions(+), 12 deletions(-)

(limited to 'modules/gallery/helpers/module.php')

diff --git a/modules/gallery/helpers/module.php b/modules/gallery/helpers/module.php
index 6c7078a3..2ae83f0d 100644
--- a/modules/gallery/helpers/module.php
+++ b/modules/gallery/helpers/module.php
@@ -119,6 +119,36 @@ class module_Core {
     return self::$active;
   }
 
+  /**
+   * Check that the module can be installed. (i.e. all the prerequistes exist)
+   * @param string $module_name
+   */
+  static function check_environment($module_name) {
+    module::_add_to_path($module_name);
+    $messages = array();
+
+    $installer_class = "{$module_name}_installer";
+    if (method_exists($installer_class, "check_environment")) {
+      $messages = call_user_func(array($installer_class, "check_environment"));
+    }
+
+    // Now the module is installed but inactive, so don't leave it in the active path
+    module::_remove_from_path($module_name);
+    return $messages;
+  }
+
+  /**
+   * Check that the module can be installed. (i.e. all the prerequistes exist)
+   * @param string $module_name
+   */
+  static function can_deactivate($module_name) {
+    $data = (object)array("module" => $module_name, "messages" => array());
+
+    module::event("pre_deactivate", $data);
+
+    return $data->messages;
+  }
+
   /**
    * Install a module.  This will call <module>_installer::install(), which is responsible for
    * creating database tables, setting module variables and calling module::set_version().
@@ -126,13 +156,8 @@ class module_Core {
    * @param string $module_name
    */
   static function install($module_name) {
-    $config = Kohana_Config::instance();
-    $kohana_modules = $config->get("core.modules");
-    array_unshift($kohana_modules, MODPATH . $module_name);
-    $config->set("core.modules",  $kohana_modules);
+    module::_add_to_path($module_name);
 
-    // Rebuild the include path so the module installer can benefit from auto loading
-    Kohana::include_paths(true);
     $installer_class = "{$module_name}_installer";
     if (method_exists($installer_class, "install")) {
       call_user_func_array(array($installer_class, "install"), array());
@@ -142,13 +167,32 @@ class module_Core {
     module::load_modules();
 
     // Now the module is installed but inactive, so don't leave it in the active path
-    array_shift($kohana_modules);
-    $config->set("core.modules",  $kohana_modules);
+    module::_remove_from_path($module_name);
 
     log::success(
       "module", t("Installed module %module_name", array("module_name" => $module_name)));
   }
 
+  private static function _add_to_path($module_name) {
+    $config = Kohana_Config::instance();
+    $kohana_modules = $config->get("core.modules");
+    array_unshift($kohana_modules, MODPATH . $module_name);
+    $config->set("core.modules",  $kohana_modules);
+    // Rebuild the include path so the module installer can benefit from auto loading
+    Kohana::include_paths(true);
+  }
+
+  private static function _remove_from_path($module_name) {
+    $config = Kohana_Config::instance();
+    $kohana_modules = $config->get("core.modules");
+    if (($key = array_search(MODPATH . $module_name, $kohana_modules)) !== false) {
+      unset($kohana_modules[$key]);
+      $kohana_modules = array_values($kohana_modules); // reindex
+    }
+    $config->set("core.modules",  $kohana_modules);
+    Kohana::include_paths(true);
+  }
+
   /**
    * Upgrade a module.  This will call <module>_installer::upgrade(), which is responsible for
    * modifying database tables, changing module variables and calling module::set_version().
@@ -194,10 +238,7 @@ class module_Core {
    * @param string $module_name
    */
   static function activate($module_name) {
-    $config = Kohana_Config::instance();
-    $kohana_modules = $config->get("core.modules");
-    array_unshift($kohana_modules, MODPATH . $module_name);
-    $config->set("core.modules",  $kohana_modules);
+    module::_add_to_path($module_name);
 
     $installer_class = "{$module_name}_installer";
     if (method_exists($installer_class, "activate")) {
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