Fix memory leak when accessing Horde headers

Horde offers access to headers either unparsed, as stream or parsed into
an object. Before the patch we used the latter. That has the current bug
that it opens a PHP memory stream, parses into an object but leaves the
stream open. If this is done thousands of times, there is a considerate
amount of memory that doesn't get freed.

With the patch we request just the stream, trigger the parsing ourselves
and close the stream afterwards. This frees the memory.

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

1 files changed, 13 insertions, 8 deletions

diff --git a/lib/Model/IMAPMessage.php b/lib/Model/IMAPMessage.php
index 0b3c38f50..67dac0237 100644
--- a/lib/Model/IMAPMessage.php
+++ b/lib/Model/IMAPMessage.php
@@ -52,6 +52,7 @@ use OCA\Mail\Service\Html;
 use OCP\AppFramework\Db\DoesNotExistException;
 use OCP\Files\File;
 use OCP\Files\SimpleFS\ISimpleFile;
+use function fclose;
 use function in_array;
 use function mb_convert_encoding;
 use function mb_strcut;
@@ -179,13 +180,15 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	}
 
 	private function getRawReferences(): string {
-		/** @var Horde_Mime_Headers $headers */
-		$headers = $this->fetch->getHeaderText('0', Horde_Imap_Client_Data_Fetch::HEADER_PARSE);
-		$header = $headers->getHeader('references');
-		if ($header === null) {
+		/** @var resource $headersStream */
+		$headersStream = $this->fetch->getHeaderText('0', Horde_Imap_Client_Data_Fetch::HEADER_STREAM);
+		$parsedHeaders = Horde_Mime_Headers::parseHeaders($headersStream);
+		fclose($headersStream);
+		$references = $parsedHeaders->getHeader('references');
+		if ($references === null) {
 			return '';
 		}
-		return $header->value_single;
+		return $references->value_single;
 	}
 
 	private function getRawInReplyTo(): string {
@@ -193,9 +196,11 @@ class IMAPMessage implements IMessage, JsonSerializable {
 	}
 
 	public function getDispositionNotificationTo(): string {
-		/** @var Horde_Mime_Headers $headers */
-		$headers = $this->fetch->getHeaderText('0', Horde_Imap_Client_Data_Fetch::HEADER_PARSE);
-		$header = $headers->getHeader('disposition-notification-to');
+		/** @var resource $headersStream */
+		$headersStream = $this->fetch->getHeaderText('0', Horde_Imap_Client_Data_Fetch::HEADER_STREAM);
+		$parsedHeaders = Horde_Mime_Headers::parseHeaders($headersStream);
+		fclose($headersStream);
+		$header = $parsedHeaders->getHeader('disposition-notification-to');
 		if ($header === null) {
 			return '';
 		}