Some additional helper functions.

islandora_is_valid_namespace()
islandora_get_allowed_namespaces()
islandora_get_content_models()

includes/utilities.inc

@@ -79,6 +79,19 @@ function islandora_is_valid_pid($pid) {
   return drupal_strlen(trim($pid)) <= 64 && preg_match('/^([A-Za-z0-9]|-|\.)+:(([A-Za-z0-9])|-|\.|~|_|(%[0-9A-F]{2}))+$/', trim($pid));
 }
 
+/**
+ * Checks if the given namespace is valid.
+ *
+ * @param string $namespace
+ *   The namespace to check without the ":" character.
+ *
+ * @return bool
+ *   TRUE if valid, FALSE otherwise.
+ */
+function islandora_is_valid_namespace($namespace) {
+  return drupal_strlen(trim($namespace)) <= 64 && preg_match('/^([A-Za-z0-9]|-|\.)+$/', trim($namespace));
+}
+
 /**
  * Checks if the given datastream id is valid.
  *
@@ -673,3 +686,55 @@ function islandora_user_access_any(array $perms, $account = NULL) {
   }
   return FALSE;
 }
+
+/**
+ * Gets the list of allowed namespaces as defined by 'islandora_pids_allowed'.
+ *
+ * @return array
+ *   The list of namespaces striped of trailing ":" characters.
+ */
+function islandora_get_allowed_namespaces() {
+  $matches = array();
+  $allowed_namespaces = variable_get('islandora_pids_allowed', 'default: demo: changeme: islandora:');
+  preg_match_all('/([A-Za-z0-9-\.]+):/', $allowed_namespaces, $matches);
+  return $matches[1];
+}
+
+/**
+ * Gets a list of all existing content models.
+ *
+ * If 'islandora_namespace_restriction_enforced' is set to true only return
+ * content models in the allowed namespace.
+ *
+ * @param bool $ignore_system_namespace
+ *   Ignore content models in the 'fedora-system' namespace.
+ *
+ * @return array
+ *   An associative array of all existing content models.
+ *   - pid: The PID of the content model object.
+ *     - pid: The PID of the content model object.
+ *     - label: The label of the content model object.
+ */
+function islandora_get_content_models($ignore_system_namespace = TRUE) {
+  module_load_include('inc', 'islandora', 'includes/utilities');
+  $tuque = islandora_get_tuque_connection();
+  $query = 'select $object $label from <#ri>
+          where ($object <fedora-model:label> $label
+          and ($object <fedora-model:hasModel> <info:fedora/fedora-system:ContentModel-3.0>
+          or $object <fedora-rels-ext:isMemberOfCollection> <info:fedora/islandora:ContentModelsCollection>)
+          and $object <fedora-model:state> <info:fedora/fedora-system:def/model#Active>)
+          order by $label';
+  $content_models = array();
+  $results = $tuque->repository->ri->itqlQuery($query, 'unlimited');
+  foreach ($results as $result) {
+    $content_model = $result['object']['value'];
+    $label = $result['label']['value'];
+    $namespace = islandora_get_namespace($content_model);
+    $ignore = $ignore_system_namespace && $namespace == 'fedora-system';
+    $ignore |= !islandora_namespace_accessible($namespace);
+    if (!$ignore) {
+      $content_models[$content_model] = array('pid' => $content_model, 'label' => $label);
+    }
+  }
+  return $content_models;
+}