From d0b49780ab5d6a0aae879b380b100fc24c4e86fc Mon Sep 17 00:00:00 2001
From: Jonathan Green <jonathan@razzard.com>
Date: Thu, 6 Sep 2018 16:31:22 -0300
Subject: [PATCH] Add hook for child relationships

---
 includes/orphaned_objects.inc | 13 +++++--------
 islandora.api.php             | 18 ++++++++++++++++++
 islandora.module              |  7 +++++++
 3 files changed, 30 insertions(+), 8 deletions(-)

diff --git a/includes/orphaned_objects.inc b/includes/orphaned_objects.inc
index 54a156ce..60ddf34d 100644
--- a/includes/orphaned_objects.inc
+++ b/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> ;
@@ -169,11 +169,7 @@ WHERE {
   FILTER (!bound(?liveparent))
 } ORDER BY ?object
 EOQ;
-  $parent_relationships = array('<fedora-rels-ext:isMemberOfCollection>', '<fedora-rels-ext:isMemberOf>', '<islandora:isPageOf>');
-  if (module_exists('islandora_compound_object')) {
-    $predicate = variable_get('islandora_compound_object_relationship', 'isConstituentOf');
-    $parent_relationships[] = "<fedora-rels-ext:$predicate>";
-  }
+  $parent_relationships = module_invoke_all('islandora_solution_pack_child_relationships');
 
   $optionals = (array) module_invoke('islandora_xacml_api', 'islandora_basic_collection_get_query_optionals', 'view');
   $filter_modules = array(
@@ -194,8 +190,9 @@ EOQ;
   $sparql_query_objects = format_string($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 = ', $parent_relationships),
-    '!live_parent_relationships' => '{' . implode(' } UNION { ', array_map($parent_map,$parent_relationships)) . '}',
+    '!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 $results;
diff --git a/islandora.api.php b/islandora.api.php
index c5de95e1..166998ac 100644
--- a/islandora.api.php
+++ b/islandora.api.php
@@ -966,3 +966,21 @@ function hook_islandora_datastream_filename_alter(&$filename, AbstractDatastream
     );
   }
 }
+
+/**
+ * Allow solution packs to register relationships used for children.
+ *
+ * @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() {
+  return array(
+    'prefix' => array('PREFIX islandora: <http://islandora.ca/ontology/relsext#>'),
+    'predicate' => array(
+      '<fedora-rels-ext:isMemberOfCollection>',
+      '<fedora-rels-ext:isMemberOf>',
+      '<islandora:isPageOf>',
+    ),
+  );
+}
\ No newline at end of file
diff --git a/islandora.module b/islandora.module
index f9276404..effa4a79 100644
--- a/islandora.module
+++ b/islandora.module
@@ -2215,3 +2215,10 @@ function islandora_islandora_breadcrumbs_backends() {
     ),
   );
 }
+
+/**
+ * Implements hook_islandora_solution_pack_child_relationships
+ */
+function islandora_islandora_solution_pack_child_relationships() {
+  return array('predicate' => array(), 'prefix' => array());
+}
\ No newline at end of file