From c4f792bd4044cdc92a7f09ed29760c3c837374ab Mon Sep 17 00:00:00 2001
From: Felix Kauselmann <licorn@gmail.com>
Date: Wed, 25 Nov 2020 21:12:16 +0100
Subject: [PATCH] Fix port settings

When setting ports, temporary or for good, we need to go via the config
files and not QTcpServer or we get undefined behavior. To support temp
ports, we need to back up the fixed port in the settings.
---
 YACReaderLibrary/server/startup.cpp | 44 +++++++++++++++++++++--------
 1 file changed, 33 insertions(+), 11 deletions(-)

diff --git a/YACReaderLibrary/server/startup.cpp b/YACReaderLibrary/server/startup.cpp
index 93781a1c..5afa00d0 100644
--- a/YACReaderLibrary/server/startup.cpp
+++ b/YACReaderLibrary/server/startup.cpp
@@ -110,20 +110,42 @@ void Startup::start(quint16 port)
     if (listenerSettings->value("minThreads").isNull())
         listenerSettings->setValue("minThreads", 50);
 
+    if (listenerSettings->value("port").isNull())
+        listenerSettings->setValue("port", 8080);
+
+    // start with a temporary port
+    if (port != 0) {
+        // cache saved port
+        if (!listenerSettings->contains("cachedPort")) {
+            listenerSettings->setValue("cachedPort", listenerSettings->value("port").toInt());
+        }
+        listenerSettings->setValue("port", port);
+    } else {
+        // restore saved port
+        if (listenerSettings->contains("cachedPort")) {
+            listenerSettings->setValue("port", listenerSettings->value("cachedPort"));
+            listenerSettings->remove("cachedPort");
+        }
+    }
+    // test if port is working
+    {
+        QTcpServer testServer;
+        if (!testServer.listen(QHostAddress::Any, listenerSettings->value("port").toInt())) {
+            qDebug("Port is busy.");
+            // get random port
+            testServer.listen(QHostAddress::Any, 0);
+            listenerSettings->setValue("port", testServer.serverPort());
+        }
+        testServer.close();
+    }
+
     listener = new HttpListener(listenerSettings, new RequestMapper(app), app);
 
-    if (port != 0) {
-        if (listener->isListening()) {
-            listener->close();
-        }
-        listener->QTcpServer::listen(QHostAddress::Any, port);
+    if (listener->isListening()) {
+        qDebug("ServiceHelper: Service has started");
+    } else {
+        qDebug("ServiceHelper: Could not launch service");
     }
-    // if the requested port is busy, use random port
-    if (!listener->isListening()) {
-        listener->QTcpServer::listen(QHostAddress::Any, 0);
-    }
-
-    qDebug("ServiceHelper: Service has started");
 }
 
 void Startup::stop()