Allow orphaned object report to find orphaned compound objects. (#710)

* Allow orphaned object report to find orphaned compound objects.

* Add hook for child relationships

* Add conditional checking if we are working with an empty set.

* Add way to filter hook on content model.

* Sacrifical commit for coding standards gods.

* Less python in example.

* More uniqueness

includes/orphaned_objects.inc

@@ -145,7 +145,7 @@ function islandora_get_orphaned_objects() {
   $connection = islandora_get_tuque_connection();
   // SPARQL: get orphaned objects, exclude any with a living parent.
   $object_query = <<<EOQ
-PREFIX islandora: <http://islandora.ca/ontology/relsext#>
+!prefix
 SELECT DISTINCT ?object ?title 
 WHERE {
   ?object <fedora-model:hasModel> <info:fedora/fedora-system:FedoraObject-3.0> ;
@@ -156,14 +156,12 @@ WHERE {
   } .
   FILTER (!bound(?model))
 
-  # Filter by "parent" relationships - isMemberOf, isMemberOfCollection, isPageOf. 
-  FILTER (?p = <fedora-rels-ext:isMemberOfCollection> || ?p = <fedora-rels-ext:isMemberOf> || ?p = <islandora:isPageOf>)
+  # Filter by "parent" relationships
+  FILTER (!dead_parent_relationships)
  
-# Exclude objects with live parents - isMemberOf, isMemberOfCollection, isPageOf.
+  # Exclude objects with live parents
   OPTIONAL {
-    {?object <fedora-rels-ext:isMemberOfCollection> ?liveparent }
-    UNION {?object <fedora-rels-ext:isMemberOf> ?liveparent } 
-    UNION { ?object <islandora:isPageOf> ?liveparent } .
+    !live_parent_relationships .
     ?liveparent <fedora-model:hasModel> <info:fedora/fedora-system:FedoraObject-3.0> .
   }
   !optionals
@@ -171,7 +169,13 @@ WHERE {
   FILTER (!bound(?liveparent))
 } ORDER BY ?object
 EOQ;
-
+  $parent_relationships = module_invoke_all('islandora_solution_pack_child_relationships', 'all');
+  $parent_relationships['prefix'] = array_unique($parent_relationships['prefix']);
+  $parent_relationships['predicate'] = array_unique($parent_relationships['predicate']);
+  if (count($parent_relationships['predicate']) == 0) {
+    // No predicates to search for. Exit early.
+    return array();
+  }
   $optionals = (array) module_invoke('islandora_xacml_api', 'islandora_basic_collection_get_query_optionals', 'view');
   $filter_modules = array(
     'islandora_xacml_api',
@@ -184,10 +188,16 @@ EOQ;
   $filter_map = function ($filter) {
     return "FILTER($filter)";
   };
+  $parent_map = function ($parent) {
+    return "?object $parent ?liveparent";
+  };
   // Use separate queries for different object types.
   $sparql_query_objects = format_string($object_query, array(
     '!optionals' => !empty($optionals) ? ('OPTIONAL {{' . implode('} UNION {', $optionals) . '}}') : '',
     '!filters' => !empty($filters) ? implode(' ', array_map($filter_map, $filters)) : '',
+    '!dead_parent_relationships' => '?p = ' . implode(' || ?p = ', $parent_relationships['predicate']),
+    '!live_parent_relationships' => '{' . implode(' } UNION { ', array_map($parent_map, $parent_relationships['predicate'])) . '}',
+    '!prefix' => implode("\n", $parent_relationships['prefix']),
   ));
   $results = $connection->repository->ri->sparqlQuery($sparql_query_objects);
   return $results;

islandora.api.php

@@ -966,3 +966,30 @@ function hook_islandora_datastream_filename_alter(&$filename, AbstractDatastream
     );
   }
 }
+
+/**
+ * Allow solution packs to register relationships used for children.
+ *
+ * @param string|array $cmodels
+ *   This takes either:
+ *      - string: the string 'all'. Function returns all child relationships.
+ *      - array: an array of cmodel PIDs to return the relationships for.
+ *
+ * @return array
+ *   - prefix (array): This is is a valid snip-it of SPARQL to register
+ *     prefixes used in the predicates array.
+ *   - predicate (array): This array contains predicates used by the solution
+ *     pack for child objects.
+ */
+function hook_islandora_solution_pack_child_relationships($cmodels) {
+  if ($cmodels === 'all' || in_array('my:cmodel_pid', $cmodels)) {
+    return array(
+      'prefix' => array('PREFIX islandora: <http://islandora.ca/ontology/relsext#>'),
+      'predicate' => array(
+        '<fedora-rels-ext:isMemberOfCollection>',
+        '<fedora-rels-ext:isMemberOf>',
+        '<islandora:isPageOf>',
+      ),
+    );
+  }
+}

islandora.module

@@ -2215,3 +2215,12 @@ function islandora_islandora_breadcrumbs_backends() {
     ),
   );
 }
+
+/**
+ * Implements hook_islandora_solution_pack_child_relationships
+ */
+function islandora_islandora_solution_pack_child_relationships($cmodels) {
+  // Return empty arrays from core implementation so that these keys always
+  // exist when the hook is called, even if no module responds.
+  return array('predicate' => array(), 'prefix' => array());
+}