Implement hasUpdated() to watch for changes on Google Drive side

diff --git a/apps/files_external/lib/google.php b/apps/files_external/lib/google.php
index df3dc41be27136c3e1df58e96b62cc755b657642..678799545d719d4112e2b5d194e01da5eaa19ea2 100644 (file)
--- a/apps/files_external/lib/google.php
+++ b/apps/files_external/lib/google.php
@@ -465,4 +465,63 @@ class Google extends \OC\Files\Storage\Common {
                return false;
        }
 
+       public function hasUpdated($path, $time) {
+               if ($this->is_file($path)) {
+                       return parent::hasUpdated($path, $time);
+               } else {
+                       // Google Drive doesn't change modified times of folders when files inside are updated
+                       // Instead we use the Changes API to see if folders have been updated, and it's a pain
+                       $folder = $this->getDriveFile($path);
+                       if ($folder) {
+                               $result = false;
+                               $folderId = $folder->getId();
+                               $startChangeId = \OC_Appconfig::getValue('files_external', $this->getId().'cId');
+                               $params = array(
+                                       'includeDeleted' => true,
+                                       'includeSubscribed' => true,
+                               );
+                               if (isset($startChangeId)) {
+                                       $startChangeId = (int)$startChangeId;
+                                       $largestChangeId = $startChangeId;
+                                       $params['startChangeId'] = $startChangeId + 1;
+                               } else {
+                                       $largestChangeId = 0;
+                               }
+                               $pageToken = true;
+                               while ($pageToken) {
+                                       if ($pageToken !== true) {
+                                               $params['pageToken'] = $pageToken;
+                                       }
+                                       $changes = $this->service->changes->listChanges($params);
+                                       if ($largestChangeId === 0 || $largestChangeId === $startChangeId) {
+                                               $largestChangeId = $changes->getLargestChangeId();
+                                       }
+                                       if (isset($startChangeId)) {
+                                               // Check if a file in this folder has been updated
+                                               // There is no way to filter by folder at the API level...
+                                               foreach ($changes->getItems() as $change) {
+                                                       foreach ($change->getFile()->getParents() as $parent) {
+                                                               if ($parent->getId() === $folderId) {
+                                                                       $result = true;
+                                                               // Check if there are changes in different folders
+                                                               } else if ($change->getId() <= $largestChangeId) {
+                                                                       // Decrement id so this change is fetched when called again
+                                                                       $largestChangeId = $change->getId();
+                                                                       $largestChangeId--;
+                                                               }
+                                                       }
+                                               }
+                                               $pageToken = $changes->getNextPageToken();
+                                       } else {
+                                               // Assuming the initial scan just occurred and changes are negligible
+                                               break;
+                                       }
+                               }
+                               \OC_Appconfig::setValue('files_external', $this->getId().'cId', $largestChangeId);
+                               return $result;
+                       }
+               }
+               return false;
+       }
+
 }
\ No newline at end of file