only collect detailed access list if it is really needed

Signed-off-by: Bjoern Schiessle <bjoern@schiessle.org>

3 files changed, 23 insertions, 2 deletions

diff --git a/lib/private/Encryption/Update.php b/lib/private/Encryption/Update.php
index ad40183767b..94d64b73504 100644
--- a/lib/private/Encryption/Update.php
+++ b/lib/private/Encryption/Update.php
@@ -168,6 +168,14 @@ class Update {
 	 */
 	public function update($path) {
 
+		$encryptionModule = $this->encryptionManager->getEncryptionModule();
+
+		// if the encryption module doesn't encrypt the files on a per-user basis
+		// we have nothing to do here.
+		if ($encryptionModule->needDetailedAccessList() === false) {
+			return;
+		}
+
 		// if a folder was shared, get a list of all (sub-)folders
 		if ($this->view->is_dir($path)) {
 			$allFiles = $this->util->getAllFiles($path);
@@ -175,7 +183,7 @@ class Update {
 			$allFiles = array($path);
 		}
 
-		$encryptionModule = $this->encryptionManager->getEncryptionModule();
+
 
 		foreach ($allFiles as $file) {
 			$usersSharing = $this->file->getAccessList($file);
diff --git a/lib/private/Files/Stream/Encryption.php b/lib/private/Files/Stream/Encryption.php
index d1f68696848..b68917ce76e 100644
--- a/lib/private/Files/Stream/Encryption.php
+++ b/lib/private/Files/Stream/Encryption.php
@@ -254,7 +254,10 @@ class Encryption extends Wrapper {
 			$sharePath = dirname($sharePath);
 		}
 
-		$accessList = $this->file->getAccessList($sharePath);
+		$accessList = [];
+		if ($this->encryptionModule->needDetailedAccessList()) {
+			$accessList = $this->file->getAccessList($sharePath);
+		}
 		$this->newHeader = $this->encryptionModule->begin($this->fullPath, $this->uid, $mode, $this->header, $accessList);
 
 		if (
diff --git a/lib/public/Encryption/IEncryptionModule.php b/lib/public/Encryption/IEncryptionModule.php
index 6be9763c9c8..d96c6c8ba06 100644
--- a/lib/public/Encryption/IEncryptionModule.php
+++ b/lib/public/Encryption/IEncryptionModule.php
@@ -182,4 +182,14 @@ interface IEncryptionModule {
 	 */
 	public function isReadyForUser($user);
 
+	/**
+	 * Does the encryption module needs a detailed list of users with access to the file?
+	 * For example if the encryption module uses per-user encryption keys and needs to know
+	 * the users with access to the file to encrypt/decrypt it.
+	 *
+	 * @since 13.0.0
+	 * @return bool
+	 */
+	public function needDetailedAccessList();
+
 }