Batch each derivative operation individually.

includes/derivatives.inc

@@ -121,3 +121,60 @@ function islandora_derivative_logging(array $logging_results) {
     }
   }
 }
+
+/**
+ * Kicks off derivative functions based upon hooks and conditions.
+ *
+ * @param AbstractObject $object
+ *   An AbstractObject representing a FedoraObject.
+ * @param array $options
+ *   An array of parameters containing:
+ *   - force: Bool denoting whether we are forcing the generation of
+ *     derivatives.
+ *   - source_dsid: (Optional) String of the datastream id we are generating
+ *     from or NULL if it's the object itself.
+ *   - destination_dsid: (Optional) String of the datastream id that is being
+ *     created. To be used in the UI.
+ *
+ * @return array
+ *   An array of operations to be called from within a batch.
+ */
+function islandora_do_batch_derivatives(AbstractObject $object, array $options) {
+  module_load_include('inc', 'islandora', 'includes/utilities');
+  $options += array(
+    'force' => FALSE,
+  );
+  $hooks = islandora_invoke_hook_list(ISLANDORA_DERVIATIVE_CREATION_HOOK, $object->models, array($object));
+  uasort($hooks, 'drupal_sort_weight');
+  $operations = array();
+
+  if (array_key_exists('source_dsid', $options)) {
+    $hooks = array_filter($hooks, function($filter_hook) use($options) {
+      return array_key_exists('source_dsid', $filter_hook) &&
+      $filter_hook['source_dsid'] == $options['source_dsid'];
+    });
+  }
+
+  if (array_key_exists('destination_dsid', $options)) {
+    $hooks = array_filter($hooks, function($filter_hook) use($options) {
+      return array_key_exists('destination_dsid', $filter_hook) &&
+      $filter_hook['destination_dsid'] == $options['destination_dsid'];
+    });
+  }
+
+  foreach ($hooks as $hook) {
+    $file = FALSE;
+    if (isset($hook['file'])) {
+      $file = $hook['file'];
+    }
+    foreach ($hook['function'] as $function) {
+      $operations[] = array('islandora_derivative_perform_batch_operation', array(
+        $function,
+        $file,
+        $object->id,
+        $options['force']),
+      );
+    }
+  }
+  return $operations;
+}

includes/regenerate_derivatives.form.inc

@@ -97,13 +97,12 @@ function islandora_regenerate_object_derivatives_form_submit(array $form, array
 function islandora_regenerate_object_derivatives_batch(AbstractObject $object) {
   return array(
     'title' => t('Regenerating all derivatives for @label', array('@label' => $object->label)),
-    'operations' => array(
-      array('islandora_regenerate_object_derivatives_batch_operation', array($object)),
-    ),
+    'operations' => islandora_do_batch_derivatives($object, array('force' => TRUE)),
     'init_message' => t('Preparing to regenerate derivatives...'),
     'progress_message' => t('Time elapsed: @elapsed <br/>Estimated time remaning @estimate.'),
     'error_message' => t('An error has occurred.'),
     'file' => drupal_get_path('module', 'islandora') . '/includes/regenerate_derivatives.form.inc',
+    'finished' => 'islandora_regenerate_derivative_batch_finished',
   );
 }
 
@@ -135,13 +134,15 @@ function islandora_regenerate_object_derivatives_batch_operation(AbstractObject
 function islandora_regenerate_datastream_derivative_batch(AbstractDatastream $datastream) {
   return array(
     'title' => t('Regenerating derivatives for the @dsid datastream', array('@dsid' => $datastream->id)),
-    'operations' => array(
-      array('islandora_regenerate_datastream_derivative_batch_operation', array($datastream)),
-    ),
+    'operations' => islandora_do_batch_derivatives($datastream->parent, array(
+        'force' => TRUE,
+        'destination_dsid' => $datastream->id,
+    )),
     'init_message' => t('Preparing to regenerate derivatives...'),
     'progress_message' => t('Time elapsed: @elapsed <br/>Estimated time remaning @estimate.'),
     'error_message' => t('An error has occurred.'),
     'file' => drupal_get_path('module', 'islandora') . '/includes/regenerate_derivatives.form.inc',
+    'finished' => 'islandora_regenerate_derivative_batch_finished',
   );
 }
 
@@ -161,3 +162,49 @@ function islandora_regenerate_datastream_derivative_batch_operation(AbstractData
   ));
   islandora_derivative_logging($logging_results);
 }
+
+/**
+ * Wrapper to call out to batch operations.
+ *
+ * @param string $function
+ *   The name of the function we are calling for derivatives.
+ * @param bool|string $file
+ *   FALSE if there is no file to load, the path to require otherwise
+ * @param string $pid
+ *   The pid of the object we are performing.
+ * @param bool $force
+ *   Whether we are forcing derivative regeneration or not.
+ * @param array $context
+ *   The context of the current batch operation.
+ */
+function islandora_derivative_perform_batch_operation($function, $file, $pid, $force, &$context) {
+  if ($file) {
+    require_once $file;
+  }
+  if (function_exists($function)) {
+    $logging = call_user_func($function, islandora_object_load($pid), $force);
+    if (!empty($logging)) {
+      $context['results']['logging'][] = $logging;
+    }
+  }
+  else {
+    watchdog('islandora', 'Unable to call derivative function @function as it was not found!', array('@function' => $function), WATCHDOG_ERROR);
+  }
+}
+
+/**
+ * Finished function for derivative batch regeneration.
+ *
+ * @param array $success
+ *   An array of success passed from the batch.
+ * @param array $results
+ *   An array of results passed from the batch.
+ * @param array $operations
+ *   An array of operations passed from the batch.
+ */
+function islandora_regenerate_derivative_batch_finished($success, $results, $operations) {
+  module_load_include('inc', 'islandora', 'includes/derivatives');
+  if (!empty($results['logging'])) {
+    islandora_derivative_logging($results['logging']);
+  }
+}