just pass the share instead of searching for it

apps/files_sharing/lib/cache.php

@@ -60,7 +60,7 @@ class Shared_Cache extends Cache {
 		if ($target === false || $target === $this->storage->getMountPoint()) {
 			$target = '';
 		}
-		$source = \OC_Share_Backend_File::getSource($target, $this->storage->getMountPoint(), $this->storage->getItemType());
+		$source = \OC_Share_Backend_File::getSource($target, $this->storage->getShare());
 		if (isset($source['path']) && isset($source['fileOwner'])) {
 			\OC\Files\Filesystem::initMountPoints($source['fileOwner']);
 			$mounts = \OC\Files\Filesystem::getMountByNumericId($source['storage']);
@@ -242,7 +242,7 @@ class Shared_Cache extends Cache {
 	 */
 	protected function getMoveInfo($path) {
 		$cache = $this->getSourceCache($path);
-		$file = \OC_Share_Backend_File::getSource($path, $this->storage->getMountPoint(), $this->storage->getItemType());
+		$file = \OC_Share_Backend_File::getSource($path, $this->storage->getShare());
 		return [$cache->getNumericStorageId(), $file['path']];
 	}
 

apps/files_sharing/lib/share/file.php

@@ -206,27 +206,15 @@ class OC_Share_Backend_File implements OCP\Share_Backend_File_Dependent {
 
 	/**
 	 * @param string $target
-	 * @param string $mountPoint
-	 * @param string $itemType
+	 * @param array $share
 	 * @return array|false source item
 	 */
-	public static function getSource($target, $mountPoint, $itemType) {
-		if ($itemType === 'folder') {
-			$source = \OCP\Share::getItemSharedWith('folder', $mountPoint, \OC_Share_Backend_File::FORMAT_SHARED_STORAGE);
-			if ($source && $target !== '') {
-				// note: in case of ext storage mount points the path might be empty
-				// which would cause a leading slash to appear
-				$source['path'] = ltrim($source['path'] . '/' . $target, '/');
-			}
-		} else {
-			$source = \OCP\Share::getItemSharedWith('file', $mountPoint, \OC_Share_Backend_File::FORMAT_SHARED_STORAGE);
-		}
-		if ($source) {
-			return self::resolveReshares($source);
+	public static function getSource($target, $share) {
+		if ($share['item_type'] === 'folder' && $target !== '') {
+			// note: in case of ext storage mount points the path might be empty
+			// which would cause a leading slash to appear
+			$share['path'] = ltrim($share['path'] . '/' . $target, '/');
 		}
-
-		\OCP\Util::writeLog('files_sharing', 'File source not found for: '.$target, \OCP\Util::DEBUG);
-		return false;
+		return self::resolveReshares($share);
 	}
-
 }

apps/files_sharing/lib/sharedstorage.php

@@ -83,14 +83,14 @@ class Shared extends \OC\Files\Storage\Common implements ISharedStorage {
 		if (!isset($this->files[$target])) {
 			// Check for partial files
 			if (pathinfo($target, PATHINFO_EXTENSION) === 'part') {
-				$source = \OC_Share_Backend_File::getSource(substr($target, 0, -5), $this->getMountPoint(), $this->getItemType());
+				$source = \OC_Share_Backend_File::getSource(substr($target, 0, -5), $this->getShare());
 				if ($source) {
 					$source['path'] .= '.part';
 					// All partial files have delete permission
 					$source['permissions'] |= \OCP\Constants::PERMISSION_DELETE;
 				}
 			} else {
-				$source = \OC_Share_Backend_File::getSource($target, $this->getMountPoint(), $this->getItemType());
+				$source = \OC_Share_Backend_File::getSource($target, $this->getShare());
 			}
 			$this->files[$target] = $source;
 		}