From 04665e4dd80d9f60dcdd35e0712f26e3aa8dbd6a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lukas=20Br=C3=BCbach?= <Bruebach.Lukas@bdosecurity.de>
Date: Sun, 5 Apr 2026 21:46:58 +0200
Subject: [PATCH] Rework

Took 30 minutes
---
 cockatrice/src/main.cpp                    |  2 +-
 cockatrice/src/single_instance_manager.cpp | 89 ++++++++++++++++++++++
 cockatrice/src/single_instance_manager.h   | 46 +----------
 3 files changed, 94 insertions(+), 43 deletions(-)

diff --git a/cockatrice/src/main.cpp b/cockatrice/src/main.cpp
index c9866b508..6b20fd0a5 100644
--- a/cockatrice/src/main.cpp
+++ b/cockatrice/src/main.cpp
@@ -348,5 +348,5 @@ int main(int argc, char *argv[])
     CountryPixmapGenerator::clear();
     UserLevelPixmapGenerator::clear();
 
-    return 0;
+    return ret;
 }
diff --git a/cockatrice/src/single_instance_manager.cpp b/cockatrice/src/single_instance_manager.cpp
index 9f5b5af38..d0be29eb3 100644
--- a/cockatrice/src/single_instance_manager.cpp
+++ b/cockatrice/src/single_instance_manager.cpp
@@ -1 +1,90 @@
 #include "single_instance_manager.h"
+
+SingleInstanceManager::SingleInstanceManager(QObject *parent) : QObject(parent)
+{
+}
+
+bool SingleInstanceManager::tryRun(const QStringList &initialFiles)
+{
+    serverName = "CockatriceSingleInstance";
+
+    QLocalSocket socket;
+    socket.connectToServer(serverName);
+
+    if (socket.waitForConnected(200)) {
+        // Serialize into buffer first
+        QByteArray payload;
+        QDataStream out(&payload, QIODevice::WriteOnly);
+        out << initialFiles;
+
+        // Prefix with size
+        QByteArray message;
+        QDataStream msgStream(&message, QIODevice::WriteOnly);
+        msgStream << quint32(payload.size());
+        message.append(payload);
+
+        socket.write(message);
+        socket.flush();
+        socket.waitForBytesWritten(1000);
+
+        return false; // Another instance is running
+    }
+
+    // No other instance → start server
+    server = new QLocalServer(this);
+
+    connect(server, &QLocalServer::newConnection, this, &SingleInstanceManager::handleNewConnection);
+
+    if (!server->listen(serverName)) {
+        QLocalServer::removeServer(serverName);
+        server->listen(serverName);
+    }
+
+    return true;
+}
+void SingleInstanceManager::handleNewConnection()
+{
+    QLocalSocket *socket = server->nextPendingConnection();
+
+    // Per-connection state
+    auto buffer = new QByteArray();
+    auto expectedSize = new quint32(0);
+
+    connect(socket, &QLocalSocket::readyRead, this, [this, socket, buffer, expectedSize]() {
+        buffer->append(socket->readAll());
+
+        QDataStream stream(buffer, QIODevice::ReadOnly);
+
+        while (true) {
+            // Step 1: read size
+            if (*expectedSize == 0) {
+                if (buffer->size() < static_cast<int>(sizeof(quint32)))
+                    return;
+
+                stream >> *expectedSize;
+            }
+
+            // Step 2: wait for full payload
+            if (buffer->size() < static_cast<int>(sizeof(quint32) + *expectedSize))
+                return;
+
+            // Step 3: extract payload
+            QByteArray payload = buffer->mid(sizeof(quint32), *expectedSize);
+
+            QDataStream payloadStream(&payload, QIODevice::ReadOnly);
+            QStringList files;
+            payloadStream >> files;
+
+            emit filesReceived(files);
+
+            // Reset buffer (single message use-case)
+            buffer->clear();
+            *expectedSize = 0;
+
+            socket->disconnectFromServer();
+            return;
+        }
+    });
+
+    connect(socket, &QLocalSocket::disconnected, socket, &QLocalSocket::deleteLater);
+}
\ No newline at end of file
diff --git a/cockatrice/src/single_instance_manager.h b/cockatrice/src/single_instance_manager.h
index 812f8d2aa..9f0e54d32 100644
--- a/cockatrice/src/single_instance_manager.h
+++ b/cockatrice/src/single_instance_manager.h
@@ -10,57 +10,19 @@ class SingleInstanceManager : public QObject
 {
     Q_OBJECT
 public:
-    explicit SingleInstanceManager(QObject *parent = nullptr) : QObject(parent)
-    {
-    }
+    explicit SingleInstanceManager(QObject *parent = nullptr);
 
-    bool tryRun(const QStringList &initialFiles)
-    {
-        serverName = "CockatriceSingleInstance";
-
-        QLocalSocket socket;
-        socket.connectToServer(serverName);
-        if (socket.waitForConnected(100)) {
-            // Another instance is running, send files/URLs to it
-            QDataStream out(&socket);
-            out << initialFiles;
-            socket.flush();
-            socket.waitForBytesWritten(1000);
-
-            return false; // Do not continue in this process
-        }
-
-        // No other instance, create server
-        server = new QLocalServer(this);
-        connect(server, &QLocalServer::newConnection, this, &SingleInstanceManager::receiveFiles);
-        if (!server->listen(serverName)) {
-            QLocalServer::removeServer(serverName);
-            server->listen(serverName);
-        }
-        return true;
-    }
+    bool tryRun(const QStringList &initialFiles);
 
 signals:
     void filesReceived(const QStringList &files);
 
 private slots:
-    void receiveFiles()
-    {
-        QLocalSocket *clientConnection = server->nextPendingConnection();
-        connect(clientConnection, &QLocalSocket::disconnected, clientConnection, &QLocalSocket::deleteLater);
-        clientConnection->waitForReadyRead(1000);
-
-        QDataStream in(clientConnection);
-        QStringList files;
-        in >> files;
-
-        emit filesReceived(files);
-        clientConnection->disconnectFromServer();
-    }
+    void handleNewConnection();
 
 private:
     QString serverName;
     QLocalServer *server = nullptr;
 };
 
-#endif // COCKATRICE_SINGLE_INSTANCE_MANAGER_H
+#endif // COCKATRICE_SINGLE_INSTANCE_MANAGER_H
\ No newline at end of file