refactor: extract logic to hide mounts and share information

The permission string for directories and files can contain M or S
depending if they are respectively coming from a mount or a share. This
information is not to be disclosed when the share is a public one.

Signed-off-by: Salvatore Martire <4652631+salmart-dev@users.noreply.github.com>

Author: salmart-dev

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

@@ -40,6 +40,7 @@
 use Sabre\HTTP\ResponseInterface;
 
 class FilesPlugin extends ServerPlugin {
+
 	// namespace
 	public const NS_OWNCLOUD = 'http://owncloud.org/ns';
 	public const NS_NEXTCLOUD = 'http://nextcloud.org/ns';
@@ -316,12 +317,7 @@ public function handleGetProperties(PropFind $propFind, \Sabre\DAV\INode $node)
 			});
 
 			$propFind->handle(self::PERMISSIONS_PROPERTYNAME, function () use ($node) {
-				$perms = $node->getDavPermissions();
-				if ($this->isPublic) {
-					// remove mount information
-					$perms = str_replace(['S', 'M'], '', $perms);
-				}
-				return $perms;
+				return $this->isPublic ? $node->getPublicDavPermissions() : $node->getDavPermissions();
 			});
 
 			$propFind->handle(self::SHARE_PERMISSIONS_PROPERTYNAME, function () use ($node, $httpRequest) {

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

@@ -337,6 +337,13 @@ public function getDavPermissions() {
 		return DavUtil::getDavPermissions($this->info);
 	}
 
+	/**
+	 * Returns the DAV Permissions with share and mount infromation stripped.
+	 */
+	public function getPublicDavPermissions(): string {
+		return str_replace(['S', 'M'], '', $this->getDavPermissions());
+	}
+
 	public function getOwner() {
 		return $this->info->getOwner();
 	}

apps/dav/tests/unit/Connector/Sabre/FilesPluginTest.php

@@ -332,9 +332,12 @@ public function testGetPublicPermissions(): void {
 
 		/** @var File&MockObject $node */
 		$node = $this->createTestNode(File::class);
-		$node->expects($this->any())
-			->method('getDavPermissions')
-			->willReturn('DWCKMSR');
+		$node->expects($this->once())
+			->method('getPublicDavPermissions')
+			->willReturn('DWCKR');
+
+		$node->expects($this->never())
+			->method('getDavPermissions');
 
 		$this->plugin->handleGetProperties(
 			$propFind,