use efficient tag retrieval on DAV report request

- uses DAV search approach against valid files joined by systemtag selector
- reduced table join for tag/systemtag search
- supports pagination
- no changes to the output formats or similar

Example request body:

<?xml version="1.0"?>
<oc:filter-files xmlns:d="DAV:" xmlns:oc="http://owncloud.org/ns" xmlns:nc="http://nextcloud.org/ns" xmlns:ocs="http://open-collaboration-services.org/ns">
  <d:prop>
    <d:getcontentlength/>
    <d:getcontenttype/>
    <d:getetag/>
    <d:getlastmodified/>
    <d:resourcetype/>
    <nc:face-detections/>
    <nc:file-metadata-size/>
    <nc:has-preview/>
    <nc:realpath/>
    <oc:favorite/>
    <oc:fileid/>
    <oc:permissions/>
    <nc:nbItems/>
  </d:prop>
  <oc:filter-rules>
    <oc:systemtag>32</oc:systemtag>
  </oc:filter-rules>
  <d:limit>
    <d:nresults>50</d:nresults>
    <nc:firstresult>0</nc:firstresult>
  </d:limit>
</oc:filter-files>

Signed-off-by: Arthur Schiwon <blizzz@arthur-schiwon.de>

apps/dav/lib/Connector/Sabre/FilesReportPlugin.php

@@ -48,6 +48,7 @@ class FilesReportPlugin extends ServerPlugin {
 
 	// namespace
 	public const NS_OWNCLOUD = 'http://owncloud.org/ns';
+	public const NS_NEXTCLOUD = 'http://nextcloud.org/ns';
 	public const REPORT_NAME = '{http://owncloud.org/ns}filter-files';
 	public const SYSTEMTAG_PROPERTYNAME = '{http://owncloud.org/ns}systemtag';
 	public const CIRCLE_PROPERTYNAME = '{http://owncloud.org/ns}circle';
@@ -186,6 +187,7 @@ class FilesReportPlugin extends ServerPlugin {
 		}
 
 		$ns = '{' . $this::NS_OWNCLOUD . '}';
+		$ncns = '{' . $this::NS_NEXTCLOUD . '}';
 		$requestedProps = [];
 		$filterRules = [];
 
@@ -199,6 +201,14 @@ class FilesReportPlugin extends ServerPlugin {
 				foreach ($reportProps['value'] as $propVal) {
 					$requestedProps[] = $propVal['name'];
 				}
+			} elseif ($name === '{DAV:}limit') {
+				foreach ($reportProps['value'] as $propVal) {
+					if ($propVal['name'] === '{DAV:}nresults') {
+						$limit = (int)$propVal['value'];
+					} elseif ($propVal['name'] === $ncns . 'firstresult') {
+						$offset = (int)$propVal['value'];
+					}
+				}
 			}
 		}
 
@@ -209,13 +219,24 @@ class FilesReportPlugin extends ServerPlugin {
 
 		// gather all file ids matching filter
 		try {
-			$resultFileIds = $this->processFilterRules($filterRules);
+			$resultFileIds = $this->processFilterRulesForFileIDs($filterRules);
+			$resultNodes = $this->processFilterRulesForFileNodes($filterRules, $limit ?? null, $offset ?? null);
 		} catch (TagNotFoundException $e) {
 			throw new PreconditionFailed('Cannot filter by non-existing tag', 0, $e);
 		}
 
+		$results = [];
+		foreach ($resultNodes as $entry) {
+			if ($entry) {
+				$results[] = $this->wrapNode($entry);
+			}
+		}
+
 		// find sabre nodes by file id, restricted to the root node path
-		$results = $this->findNodesByFileIds($reportTargetNode, $resultFileIds);
+		$additionalNodes = $this->findNodesByFileIds($reportTargetNode, $resultFileIds);
+		if (!empty($additionalNodes)) {
+			$results = array_intersect($results, $additionalNodes);
+		}
 
 		$filesUri = $this->getFilesBaseUri($uri, $reportTargetNode->getPath());
 		$responses = $this->prepareResponses($filesUri, $requestedProps, $results);
@@ -264,16 +285,12 @@ class FilesReportPlugin extends ServerPlugin {
 	 *
 	 * @throws TagNotFoundException whenever a tag was not found
 	 */
-	protected function processFilterRules($filterRules) {
+	protected function processFilterRulesForFileIDs($filterRules) {
 		$ns = '{' . $this::NS_OWNCLOUD . '}';
 		$resultFileIds = null;
-		$systemTagIds = [];
 		$circlesIds = [];
 		$favoriteFilter = null;
 		foreach ($filterRules as $filterRule) {
-			if ($filterRule['name'] === $ns . 'systemtag') {
-				$systemTagIds[] = $filterRule['value'];
-			}
 			if ($filterRule['name'] === self::CIRCLE_PROPERTYNAME) {
 				$circlesIds[] = $filterRule['value'];
 			}
@@ -289,15 +306,6 @@ class FilesReportPlugin extends ServerPlugin {
 			}
 		}
 
-		if (!empty($systemTagIds)) {
-			$fileIds = $this->getSystemTagFileIds($systemTagIds);
-			if (empty($resultFileIds)) {
-				$resultFileIds = $fileIds;
-			} else {
-				$resultFileIds = array_intersect($fileIds, $resultFileIds);
-			}
-		}
-
 		if (!empty($circlesIds)) {
 			$fileIds = $this->getCirclesFileIds($circlesIds);
 			if (empty($resultFileIds)) {
@@ -310,6 +318,25 @@ class FilesReportPlugin extends ServerPlugin {
 		return $resultFileIds;
 	}
 
+	protected function processFilterRulesForFileNodes(array $filterRules, ?int $limit, ?int $offset): array {
+		$systemTagIds = [];
+		foreach ($filterRules as $filterRule) {
+			if ($filterRule['name'] === self::SYSTEMTAG_PROPERTYNAME) {
+				$systemTagIds[] = $filterRule['value'];
+			}
+		}
+
+		$nodes = [];
+
+		if (!empty($systemTagIds)) {
+			$tags = $this->tagManager->getTagsByIds($systemTagIds);
+			$tagName = (current($tags))->getName();
+			$nodes = $this->userFolder->searchBySystemTag($tagName, $this->userSession->getUser()->getUID(), $limit ?? 0, $offset ?? 0);
+		}
+
+		return $nodes;
+	}
+
 	private function getSystemTagFileIds($systemTagIds) {
 		$resultFileIds = null;
 
@@ -406,7 +433,10 @@ class FilesReportPlugin extends ServerPlugin {
 	 * @param array $fileIds file ids
 	 * @return Node[] array of Sabre nodes
 	 */
-	public function findNodesByFileIds($rootNode, $fileIds) {
+	public function findNodesByFileIds($rootNode, $fileIds): array {
+		if (empty($fileIds)) {
+			return [];
+		}
 		$folder = $this->userFolder;
 		if (trim($rootNode->getPath(), '/') !== '') {
 			$folder = $folder->get($rootNode->getPath());
@@ -417,17 +447,21 @@ class FilesReportPlugin extends ServerPlugin {
 			$entry = $folder->getById($fileId);
 			if ($entry) {
 				$entry = current($entry);
-				if ($entry instanceof \OCP\Files\File) {
-					$results[] = new File($this->fileView, $entry);
-				} elseif ($entry instanceof \OCP\Files\Folder) {
-					$results[] = new Directory($this->fileView, $entry);
-				}
+				$results[] = $this->wrapNode($entry);
 			}
 		}
 
 		return $results;
 	}
 
+	protected function wrapNode(\OCP\Files\File|\OCP\Files\Folder $node): File|Directory {
+		if ($node instanceof \OCP\Files\File) {
+			return new File($this->fileView, $node);
+		} else {
+			return new Directory($this->fileView, $node);
+		}
+	}
+
 	/**
 	 * Returns whether the currently logged in user is an administrator
 	 */

lib/private/Files/Cache/QuerySearchHelper.php

@@ -36,6 +36,7 @@ use OCP\Files\IMimeTypeLoader;
 use OCP\Files\IRootFolder;
 use OCP\Files\Mount\IMountPoint;
 use OCP\Files\Search\ISearchBinaryOperator;
+use OCP\Files\Search\ISearchComparison;
 use OCP\Files\Search\ISearchQuery;
 use OCP\IDBConnection;
 use Psr\Log\LoggerInterface;
@@ -151,22 +152,26 @@ class QuerySearchHelper {
 			if ($user === null) {
 				throw new \InvalidArgumentException("Searching by tag requires the user to be set in the query");
 			}
-			$query
-				->leftJoin('file', 'vcategory_to_object', 'tagmap', $builder->expr()->eq('file.fileid', 'tagmap.objid'))
-				->leftJoin('tagmap', 'vcategory', 'tag', $builder->expr()->andX(
-					$builder->expr()->eq('tagmap.type', 'tag.type'),
-					$builder->expr()->eq('tagmap.categoryid', 'tag.id'),
-					$builder->expr()->eq('tag.type', $builder->createNamedParameter('files')),
-					$builder->expr()->eq('tag.uid', $builder->createNamedParameter($user->getUID()))
-				))
-				->leftJoin('file', 'systemtag_object_mapping', 'systemtagmap', $builder->expr()->andX(
-					$builder->expr()->eq('file.fileid', $builder->expr()->castColumn('systemtagmap.objectid', IQueryBuilder::PARAM_INT)),
-					$builder->expr()->eq('systemtagmap.objecttype', $builder->createNamedParameter('files'))
-				))
-				->leftJoin('systemtagmap', 'systemtag', 'systemtag', $builder->expr()->andX(
-					$builder->expr()->eq('systemtag.id', 'systemtagmap.systemtagid'),
-					$builder->expr()->eq('systemtag.visibility', $builder->createNamedParameter(true))
-				));
+			if ($searchQuery->getSearchOperation() instanceof ISearchComparison && $searchQuery->getSearchOperation()->getField() === 'systemtag') {
+				$query
+					->leftJoin('file', 'systemtag_object_mapping', 'systemtagmap', $builder->expr()->andX(
+						$builder->expr()->eq('file.fileid', $builder->expr()->castColumn('systemtagmap.objectid', IQueryBuilder::PARAM_INT)),
+						$builder->expr()->eq('systemtagmap.objecttype', $builder->createNamedParameter('files'))
+					))
+					->leftJoin('systemtagmap', 'systemtag', 'systemtag', $builder->expr()->andX(
+						$builder->expr()->eq('systemtag.id', 'systemtagmap.systemtagid'),
+						$builder->expr()->eq('systemtag.visibility', $builder->createNamedParameter(true))
+					));
+			} else {
+				$query
+					->leftJoin('file', 'vcategory_to_object', 'tagmap', $builder->expr()->eq('file.fileid', 'tagmap.objid'))
+					->leftJoin('tagmap', 'vcategory', 'tag', $builder->expr()->andX(
+						$builder->expr()->eq('tagmap.type', 'tag.type'),
+						$builder->expr()->eq('tagmap.categoryid', 'tag.id'),
+						$builder->expr()->eq('tag.type', $builder->createNamedParameter('files')),
+						$builder->expr()->eq('tag.uid', $builder->createNamedParameter($user->getUID()))
+					));
+			}
 		}
 
 		$this->applySearchConstraints($query, $searchQuery, $caches);

lib/private/Files/Node/Folder.php

@@ -297,7 +297,12 @@ class Folder extends Node implements \OCP\Files\Folder {
 	 * @return Node[]
 	 */
 	public function searchByTag($tag, $userId) {
-		$query = $this->queryFromOperator(new SearchComparison(ISearchComparison::COMPARE_EQUAL, 'tagname', $tag), $userId);
+		$query = $this->queryFromOperator(new SearchComparison(ISearchComparison::COMPARE_EQUAL, 'tag', $tag), $userId);
+		return $this->search($query);
+	}
+
+	public function searchBySystemTag(string $tag, string $userId, int $limit = 0, int $offset = 0): array {
+		$query = $this->queryFromOperator(new SearchComparison(ISearchComparison::COMPARE_EQUAL, 'systemtag', $tag), $userId, $limit, $offset);
 		return $this->search($query);
 	}
 

lib/private/SystemTag/SystemTagObjectMapper.php

@@ -135,6 +135,7 @@ class SystemTagObjectMapper implements ISystemTagObjectMapper {
 		while ($row = $result->fetch()) {
 			$objectIds[] = $row['objectid'];
 		}
+		$result->closeCursor();
 
 		return $objectIds;
 	}