From 163fd9d27381df3b2b92ad54e0cf7801571d2379 Mon Sep 17 00:00:00 2001
From: Jonathan Green <jonathan@razzard.com>
Date: Fri, 7 Sep 2018 08:32:27 -0300
Subject: [PATCH] Add way to filter hook on content model.

---
 includes/orphaned_objects.inc |  2 +-
 islandora.api.php             | 33 +++++++++++++++++++++------------
 islandora.module              |  4 +++-
 3 files changed, 25 insertions(+), 14 deletions(-)

diff --git a/includes/orphaned_objects.inc b/includes/orphaned_objects.inc
index 1d90b4d7..7393971d 100644
--- a/includes/orphaned_objects.inc
+++ b/includes/orphaned_objects.inc
@@ -169,7 +169,7 @@ WHERE {
   FILTER (!bound(?liveparent))
 } ORDER BY ?object
 EOQ;
-  $parent_relationships = module_invoke_all('islandora_solution_pack_child_relationships');
+  $parent_relationships = module_invoke_all('islandora_solution_pack_child_relationships', 'all');
   if (count($parent_relationships['predicate']) == 0) {
     // No predicates to search for. Exit early.
     return array();
diff --git a/islandora.api.php b/islandora.api.php
index 166998ac..c2d391e6 100644
--- a/islandora.api.php
+++ b/islandora.api.php
@@ -970,17 +970,26 @@ function hook_islandora_datastream_filename_alter(&$filename, AbstractDatastream
 /**
  * Allow solution packs to register relationships used for children.
  *
+ * @param string|array $cmodels
+ *   This takes either:
+ *      - string: the string 'all'. Function returns all child relationships.
+ *      - array: an array of cmodel PIDs to return the relationships for.
+ *
  * @return array
- *   - prefix (array): This is is a valid snip-it of SPARQL to register prefixes used in the predicates array.
- *   - predicate (array): This array contains predicates used by the solution pack for child objects.
- */
-function hook_islandora_solution_pack_child_relationships() {
-  return array(
-    'prefix' => array('PREFIX islandora: <http://islandora.ca/ontology/relsext#>'),
-    'predicate' => array(
-      '<fedora-rels-ext:isMemberOfCollection>',
-      '<fedora-rels-ext:isMemberOf>',
-      '<islandora:isPageOf>',
-    ),
-  );
+ *   - prefix (array): This is is a valid snip-it of SPARQL to register
+ *     prefixes used in the predicates array.
+ *   - predicate (array): This array contains predicates used by the solution
+ *     pack for child objects.
+ */
+function hook_islandora_solution_pack_child_relationships($cmodels) {
+  if ($cmodels === 'all' or in_array('my:cmodel_pid', $cmodels)) {
+    return array(
+      'prefix' => array('PREFIX islandora: <http://islandora.ca/ontology/relsext#>'),
+      'predicate' => array(
+        '<fedora-rels-ext:isMemberOfCollection>',
+        '<fedora-rels-ext:isMemberOf>',
+        '<islandora:isPageOf>',
+      ),
+    );
+  }
 }
\ No newline at end of file
diff --git a/islandora.module b/islandora.module
index effa4a79..bbce6d1e 100644
--- a/islandora.module
+++ b/islandora.module
@@ -2219,6 +2219,8 @@ function islandora_islandora_breadcrumbs_backends() {
 /**
  * Implements hook_islandora_solution_pack_child_relationships
  */
-function islandora_islandora_solution_pack_child_relationships() {
+function islandora_islandora_solution_pack_child_relationships($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());
 }
\ No newline at end of file