From 47874b37068290dda8705b5d47e0f320f3949a6d Mon Sep 17 00:00:00 2001
From: Albert S <mail@quitesimple.org>
Date: Sat, 27 Aug 2022 10:21:58 +0200
Subject: [PATCH] gui: ipcworker,ipcserver: Refactor

Crashes were observed, faulting in libQtNetwork.
Those were rather rare. We also have no traces.

Probably depends on some order signal/slots were
processed. Remove shared states between connections,
such as the IPCPreviewWorker and socket instance in IPCServer.
---
 gui/ipcpreviewworker.cpp | 44 +++++++++++++++++++++++++++++++++++-----
 gui/ipcpreviewworker.h   | 14 ++++++++++---
 gui/ipcserver.cpp        | 29 ++++++++++++--------------
 gui/ipcserver.h          |  3 ---
 4 files changed, 63 insertions(+), 27 deletions(-)

diff --git a/gui/ipcpreviewworker.cpp b/gui/ipcpreviewworker.cpp
index 8d39391..7b11970 100644
--- a/gui/ipcpreviewworker.cpp
+++ b/gui/ipcpreviewworker.cpp
@@ -1,16 +1,50 @@
 #include <QtConcurrent>
 #include "ipcpreviewworker.h"
 #include "previewgeneratormapfunctor.h"
-IPCPreviewWorker::IPCPreviewWorker()
+IPCPreviewWorker::IPCPreviewWorker(QLocalSocket *peer)
 {
+	this->peer = peer;
 	this->connect(&previewWorkerWatcher, &QFutureWatcher<QByteArray>::resultReadyAt, this,
-				  [this](int index) { emit previewGenerated(previewWorkerWatcher.resultAt(index)); });
-	connect(&previewWorkerWatcher, &QFutureWatcher<QByteArray>::finished, this, [this] { emit finished(); });
+				  [this](int index)
+				  {
+					  if(this->peer != nullptr)
+					  {
+						  QDataStream stream{this->peer};
+						  stream << previewWorkerWatcher.resultAt(index);
+						  this->peer->flush();
+					  }
+				  });
+	connect(&previewWorkerWatcher, &QFutureWatcher<QByteArray>::finished, this, &IPCPreviewWorker::shutdownSocket);
+	connect(this->peer, &QLocalSocket::disconnected, this, &IPCPreviewWorker::shutdownSocket);
 }
 
-void IPCPreviewWorker::start(RenderConfig config, const QVector<RenderTarget> &targets, QLocalSocket *peer)
+void IPCPreviewWorker::shutdownSocket()
+{
+	if(cleaned)
+	{
+		return;
+	}
+	cleaned = true;
+	if(this->peer != nullptr)
+	{
+		if(this->peer->state() == QLocalSocket::ConnectedState)
+		{
+			this->peer->flush();
+			this->peer->waitForBytesWritten();
+			this->peer->disconnectFromServer();
+			if(this->peer->state() != QLocalSocket::UnconnectedState)
+			{
+				this->peer->waitForDisconnected();
+			}
+		}
+		delete this->peer;
+		this->peer = nullptr;
+	}
+	emit finished();
+}
+
+void IPCPreviewWorker::start(RenderConfig config, const QVector<RenderTarget> &targets)
 {
-	stop();
 	auto mapFunctor = PreviewGeneratorMapFunctor();
 	mapFunctor.setRenderConfig(config);
 
diff --git a/gui/ipcpreviewworker.h b/gui/ipcpreviewworker.h
index cc7959c..52f5548 100644
--- a/gui/ipcpreviewworker.h
+++ b/gui/ipcpreviewworker.h
@@ -11,13 +11,21 @@ class IPCPreviewWorker : public QObject
 	Q_OBJECT
   private:
 	QFutureWatcher<QByteArray> previewWorkerWatcher;
+	QLocalSocket *peer;
+	bool cleaned = false;
 
   public:
-	IPCPreviewWorker();
-	void start(RenderConfig config, const QVector<RenderTarget> &targets, QLocalSocket *peer);
+	IPCPreviewWorker(QLocalSocket *peer);
+	void start(RenderConfig config, const QVector<RenderTarget> &targets);
 	void stop();
+	~IPCPreviewWorker()
+	{
+		delete this->peer;
+	}
+  private slots:
+	void shutdownSocket();
+
   signals:
-	void previewGenerated(QByteArray);
 	void finished();
 };
 
diff --git a/gui/ipcserver.cpp b/gui/ipcserver.cpp
index 89d82aa..484bee9 100644
--- a/gui/ipcserver.cpp
+++ b/gui/ipcserver.cpp
@@ -18,8 +18,6 @@ IpcServer::IpcServer()
 	/* Only 1, we are doing work for the GUI, not a service for general availability */
 	this->spawningServer.setMaxPendingConnections(1);
 	connect(&this->spawningServer, &QLocalServer::newConnection, this, &IpcServer::spawnerNewConnection);
-	connect(&this->previewWorker, &IPCPreviewWorker::previewGenerated, this, &IpcServer::handlePreviewGenerated);
-	connect(&this->previewWorker, &IPCPreviewWorker::finished, this, [this] { this->currentSocket->flush(); });
 }
 
 bool IpcServer::startSpawner(QString socketPath)
@@ -31,8 +29,6 @@ bool IpcServer::startSpawner(QString socketPath)
 void IpcServer::spawnerNewConnection()
 {
 	QLocalSocket *socket = this->spawningServer.nextPendingConnection();
-	connect(socket, &QLocalSocket::disconnected, socket, &QLocalSocket::deleteLater);
-	this->currentSocket = socket;
 	if(socket != nullptr)
 	{
 		if(!socket->waitForReadyRead())
@@ -53,21 +49,22 @@ void IpcServer::spawnerNewConnection()
 				stream.startTransaction();
 				stream >> renderConfig >> targets;
 			} while(!stream.commitTransaction() && socket->state() == QLocalSocket::ConnectedState);
-
-			stream << targets.count();
-			socket->flush();
-			previewWorker.start(renderConfig, targets, socket);
+			if(socket->state() == QLocalSocket::ConnectedState)
+			{
+				stream << targets.count();
+				socket->flush();
+				IPCPreviewWorker *previewWorker = new IPCPreviewWorker(socket);
+				connect(previewWorker, &IPCPreviewWorker::finished, this, [previewWorker] { delete previewWorker; });
+				previewWorker->start(renderConfig, targets);
+			}
+			else
+			{
+				delete socket;
+			}
 		}
 		if(command == StopGeneratePreviews)
 		{
-			previewWorker.stop();
+			/* TODO: implement */
 		}
 	}
 }
-
-void IpcServer::handlePreviewGenerated(QByteArray ba)
-{
-	QDataStream stream{this->currentSocket};
-	stream << ba;
-	this->currentSocket->flush();
-}
diff --git a/gui/ipcserver.h b/gui/ipcserver.h
index 572ec00..ebf59cb 100644
--- a/gui/ipcserver.h
+++ b/gui/ipcserver.h
@@ -10,13 +10,10 @@ class IpcServer : public QObject
 {
 	Q_OBJECT
   private:
-	IPCPreviewWorker previewWorker;
 	QLocalServer spawningServer;
-	QLocalSocket *currentSocket = nullptr;
 	SaveFileResult addFile(QString file);
   private slots:
 	void spawnerNewConnection();
-	void handlePreviewGenerated(QByteArray ba);
 
   public:
 	IpcServer();