Added ability to revert to previous versions of datastreams.

includes/datastream.version.inc

@@ -18,7 +18,7 @@ function islandora_datastream_version_table($datastream) {
   $header[] = array('data' => t('Size'));
   $header[] = array('data' => t('Label'));
   $header[] = array('data' => t('Mime type'));
-  $header[] = array('data' => t('Operations'));
+  $header[] = array('data' => t('Operations'), 'colspan' => '2');
   $rows = array();
 
   foreach ($datastream as $version => $datastream_version) {
@@ -50,6 +50,13 @@ function islandora_datastream_version_table($datastream) {
         'version' => $version,
       )),
     );
+    $row[] = array(
+      'class' => 'datastream-revert',
+      'data' => theme('islandora_datastream_revert_link', array(
+        'datastream' => $datastream,
+        'version' => $version,
+      )),
+    );
     $rows[] = $row;
   }
 
@@ -125,3 +132,84 @@ function islandora_delete_datastream_version_form_submit(array $form, array &$fo
 
   $form_state['redirect'] = "islandora/object/{$object->id}/datastream/{$datastream->id}/version";
 }
+
+/**
+ * The admin revert datastream form.
+ *
+ * @param array $form
+ *   The Drupal form.
+ * @param array $form_state
+ *   The Drupal form state.
+ * @param AbstractDatastream $datastream
+ *   The datastream to be deleted.
+ * @param string $version
+ *   The version number of the datastream we are trying to delete.
+ *
+ * @return array
+ *   The drupal form definition.
+ */
+function islandora_revert_datastream_version_form(array $form, array &$form_state, AbstractDatastream $datastream, $version) {
+  if (!isset($datastream[$version]) || count($datastream) < 2) {
+    return drupal_not_found();
+  }
+
+  $form_state['dsid'] = $datastream->id;
+  $form_state['object_id'] = $datastream->parent->id;
+  $form_state['version'] = $version;
+
+  return confirm_form($form,
+    t('Are you sure you want to revert to version @version of the @dsid datastream?', array('@dsid' => $datastream->id, '@version' => $version)),
+    "islandora/object/{$datastream->parent->id}",
+    "",
+    t('Revert'),
+    t('Cancel')
+  );
+}
+
+/**
+ * Submit handler for the revert datastream form.
+ *
+ * Purges/Delete's the given AbstractDatastream if possible.
+ *
+ * The ISLANDORA_PRE_PURGE_DATASTREAM_HOOK will query other modules as to
+ * whether the given FedoraDatastream
+ * should be: blocked from purging; state set to 'Deleted'; or purged.
+ *
+ * @param array $form
+ *   The Drupal form.
+ * @param array $form_state
+ *   The Drupal form state.
+ */
+function islandora_revert_datastream_version_form_submit(array $form, array &$form_state) {
+  $islandora_object = islandora_object_load($form_state['object_id']);
+
+  $datastream_to_revert = $islandora_object[$form_state['dsid']];
+  $version = $form_state['version'];
+
+  // Create file holding specified datastream version, and set datastream to it.
+  $datastream_to_revert_to = $datastream_to_revert[$version];
+  if (in_array($datastream_to_revert->controlGroup, array('R', 'E'))) {
+    $datastream_to_revert->url = $datastream_to_revert_to->url;
+  }
+  else {
+    $filename = file_create_filename('datastream_temp_file', '.');
+    $datastream_to_revert_to->getContent($filename);
+    $datastream_to_revert->setContentFromFile($filename);
+    file_unmanaged_delete($filename);
+  }
+
+  if ($datastream_to_revert->mimeType != $datastream_to_revert_to->mimeType) {
+    $datastream_to_revert->mimeType = $datastream_to_revert_to->mimeType;
+  }
+  if ($datastream_to_revert->label != $datastream_to_revert_to->label) {
+    $datastream_to_revert->label = $datastream_to_revert_to->label;
+  }
+
+  drupal_set_message(t('%d datastream successfully reverted to version %v for Islandora object %o', array(
+        '%d' => $datastream_to_revert->id,
+        '%v' => $version,
+        '%o' => $islandora_object->label)));
+
+  $form_state['redirect'] = "islandora/object/{$islandora_object->id}/datastream/{$datastream_to_revert->id}/version";
+}
+

islandora.module

@@ -34,6 +34,7 @@ define('ISLANDORA_INGEST', 'ingest fedora objects');
 define('ISLANDORA_PURGE', 'delete fedora objects and datastreams');
 define('ISLANDORA_MANAGE_PROPERTIES', 'manage object properties');
 define('ISLANDORA_VIEW_DATASTREAM_HISTORY', 'view old datastream versions');
+define('ISLANDORA_REVERT_DATASTREAM', 'revert to old datastream');
 
 // Hooks.
 define('ISLANDORA_VIEW_HOOK', 'islandora_view_object');
@@ -276,6 +277,16 @@ function islandora_menu() {
     'access arguments' => array(ISLANDORA_PURGE, 4),
     'load arguments' => array(2),
   );
+  $items['islandora/object/%islandora_object/datastream/%islandora_datastream/version/%/revert'] = array(
+    'title' => 'Revert to datastream version',
+    'page arguments' => array('islandora_revert_datastream_version_form', 4, 6),
+    'page callback' => 'drupal_get_form',
+    'file' => 'includes/datastream.version.inc',
+    'type' => MENU_CALLBACK,
+    'access callback' => 'islandora_datastream_access',
+    'access arguments' => array(ISLANDORA_REVERT_DATASTREAM, 4),
+    'load arguments' => array(2),
+  );
   $items['islandora/object/%islandora_object/datastream/%islandora_datastream/version/%/view'] = array(
     'title' => 'View datastream version',
     'page callback' => 'islandora_view_datastream',
@@ -380,6 +391,10 @@ function islandora_theme() {
       'file' => 'theme/theme.inc',
       'variables' => array('datastream' => NULL, 'version' => NULL),
     ),
+    'islandora_datastream_revert_link' => array(
+      'file' => 'theme/theme.inc',
+      'variables' => array('datastream' => NULL, 'version' => NULL),
+    ),
     'islandora_datastream_view_link' => array(
       'file' => 'theme/theme.inc',
       'variables' => array(
@@ -432,6 +447,10 @@ function islandora_permission() {
       'title' => t('View datastream history'),
       'description' => t('View all previous versions of a datastream.'),
     ),
+    ISLANDORA_REVERT_DATASTREAM => array(
+      'title' => t('Revert datastream history'),
+      'description' => t('Revert to a previous version of a datastream.'),
+    ),
   );
 }
 
@@ -1552,3 +1571,4 @@ function islandora_islandora_datastream_modified(AbstractObject $object, Abstrac
   ));
   islandora_derivative_logging($logging_results);
 }
+

theme/theme.inc

@@ -339,6 +339,40 @@ function theme_islandora_datastream_delete_link(array $vars) {
   }
 }
 
+/**
+ * Renders a link to allow replacing of a datatream.
+ *
+ * @param array $vars
+ *   An array containing:
+ *   - datastream: An AbstractDatastream for which to generate a revert link.
+ *   - version: (optional) the version of the datastream to revert.
+ *
+ * @return string
+ *   Markup containing the url to delete a datastream, or empty if inaccessible.
+ */
+function theme_islandora_datastream_revert_link(array $vars) {
+  $datastream = $vars['datastream'];
+
+  $can_revert = islandora_datastream_access(ISLANDORA_REVERT_DATASTREAM, $datastream);
+
+  if ($vars['version'] !== NULL) {
+    if (count($datastream) == 1) {
+      $can_revert = FALSE;
+    }
+    $link = "islandora/object/{$datastream->parent->id}/datastream/{$datastream->id}/version/{$vars['version']}/revert";
+  }
+  else {
+    $link = "islandora/object/{$datastream->parent->id}/datastream/{$datastream->id}/revert";
+  }
+
+  if ($can_revert) {
+    return l(t('revert'), $link);
+  }
+  else {
+    '';
+  }
+}
+
 /**
  * Renders a link to allow editing of a datatream.
  *
@@ -389,3 +423,4 @@ function theme_islandora_datastream_version_link(array $vars) {
     return '';
   }
 }
+