Move XSLTProcessor class check to hook_requirements()

includes/admin.form.inc

@@ -20,11 +20,6 @@ function islandora_repository_admin(array $form, array &$form_state) {
   module_load_include('inc', 'islandora', 'includes/utilities');
   drupal_add_css(drupal_get_path('module', 'islandora') . '/css/islandora.admin.css');
   
-  if (!class_exists('XSLTProcessor', FALSE)) {
-    $link = l(t('PHP XSL extension'), 'http://us2.php.net/manual/en/book.xsl.php', array('attributes' => array('target'=>'_blank')));
-    drupal_set_message(t('The !xsllink is required. Check your installed PHP extensions and php.ini file.', array('!xsllink' => $link)),'error');
-  }
-
   $form = array();
   if (isset($form_state['values']['islandora_base_url'])) {
     $url = $form_state['values']['islandora_base_url'];

islandora.install

@@ -4,6 +4,25 @@
  * @file
  * This file contains all install related hooks.
  */
+ 
+/**
+ * Implements hook_requirements().
+ */
+function islandora_requirements($phase) {
+  $requirements = array();
+  // Ensure translations don't break at install time
+  $t = get_t();
+
+  if (!class_exists('XSLTProcessor', FALSE)) {
+    $requirements['islandora_xsltprocessor']['title'] = $t('Islandora XSLTProcessor Prerequisite');
+    $requirements['islandora_xsltprocessor']['value'] = $t('Not installed');
+    $link = l($t('PHP XSL extension'), 'http://us2.php.net/manual/en/book.xsl.php', array('attributes' => array('target'=>'_blank')));
+    $requirements['islandora_xsltprocessor']['description'] = $t('The !xsllink is required. Check your installed PHP extensions and php.ini file.', array('!xsllink' => $link)),'error');
+    $requirements['islandora_xsltprocessor']['severity'] = REQUIREMENT_ERROR;
+  }
+  
+  return $requirements;
+}
 
 /**
  * Implements hook_install().