refactor: Run legacy daemon loop in thread

src/apps/deskflow-daemon/deskflow-daemon.cpp

@@ -5,6 +5,9 @@
  * SPDX-License-Identifier: GPL-2.0-only WITH LicenseRef-OpenSSL-Exception
  */
 
+#include "arch/Arch.h"
+#include "base/EventQueue.h"
+#include "base/Log.h"
 #include "deskflow/DaemonApp.h"
 
 #include "arch/Arch.h"
@@ -20,10 +23,13 @@
 
 #endif
 
+#include <QCoreApplication>
+#include <QThread>
+
 int main(int argc, char **argv)
 {
 #if SYSAPI_WIN32
-  // win32 instance needed for threading, etc.
+  // Save window instance for later use, e.g. `GetModuleFileName` which is used when installing the daemon.
   ArchMiscWindows::setInstanceWin32(GetModuleHandle(nullptr));
 #endif
 
@@ -33,8 +39,24 @@ int main(int argc, char **argv)
   Log log;
   EventQueue events;
 
-  DaemonApp app(&events, __argc, __argv);
+  LOG((CLOG_PRINT "%s daemon (v%s)", kAppName, kVersion));
-  return DaemonApp::exec();
+
+  QCoreApplication app(argc, argv);
+
+  // Must be on the heap, as we're moving it to a thread.
+  DaemonApp *pDaemon = new DaemonApp(&events);
+  QObject::connect(pDaemon, &DaemonApp::serviceInstalled, &app, &QCoreApplication::quit);
+  QObject::connect(pDaemon, &DaemonApp::serviceUninstalled, &app, &QCoreApplication::quit);
+  pDaemon->init(argc, argv);
+
+  QThread *thread = new QThread();
+  pDaemon->moveToThread(thread);
+  QObject::connect(thread, &QThread::started, pDaemon, &DaemonApp::run);
+  QObject::connect(thread, &QThread::finished, pDaemon, &QObject::deleteLater);
+  QObject::connect(thread, &QThread::finished, thread, &QThread::deleteLater);
+  thread->start();
+
+  return QCoreApplication::exec();
 }
 
 #if SYSAPI_WIN32

src/lib/deskflow/DaemonApp.cpp

@@ -13,6 +13,7 @@
 #include "base/Log.h"
 #include "base/TMethodEventJob.h"
 #include "base/log_outputters.h"
+#include "common/constants.h"
 #include "common/ipc.h"
 #include "deskflow/App.h"
 #include "deskflow/ArgParser.h"
@@ -42,6 +43,10 @@
 
 #endif
 
+#include <QCoreApplication>
+#include <QObject>
+#include <QThread>
+
 #include <memory>
 #include <sstream>
 #include <string>
@@ -96,16 +101,13 @@ int winMainLoopStatic(int, const char **)
 }
 #endif
 
-DaemonApp::DaemonApp(IEventQueue *events, int argc, char **argv)
+DaemonApp::DaemonApp(IEventQueue *events) : m_ipcServer{new ipc::DaemonIpcServer(this)}
-    : QCoreApplication(argc, argv),
-      m_events(events),
-      m_ipcServer{new ipc::DaemonIpcServer(this)}
 {
+  s_instance = this;
+
   connect(m_ipcServer, &ipc::DaemonIpcServer::elevateModeChanged, this, &DaemonApp::handleElevateModeChanged);
   connect(m_ipcServer, &ipc::DaemonIpcServer::commandChanged, this, &DaemonApp::handleCommandChanged);
   connect(m_ipcServer, &ipc::DaemonIpcServer::restartRequested, this, &DaemonApp::handleRestartRequested);
-
-  s_instance = this;
 }
 
 DaemonApp::~DaemonApp()
@@ -113,6 +115,25 @@ DaemonApp::~DaemonApp()
   s_instance = nullptr;
 }
 
+void DaemonApp::run()
+{
+  if (m_foreground) {
+    LOG((CLOG_NOTE "starting daemon in foreground"));
+
+    // run process in foreground instead of daemonizing.
+    // useful for debugging.
+    mainLoop(false, m_foreground);
+  } else {
+#if SYSAPI_WIN32
+    LOG((CLOG_NOTE "daemonizing windows service"));
+    ARCH->daemonize(kAppName, winMainLoopStatic);
+#elif SYSAPI_UNIX
+    LOG((CLOG_NOTE "daemonizing unix service"));
+    ARCH->daemonize(kAppName, unixMainLoopStatic);
+#endif
+  }
+}
+
 void DaemonApp::handleElevateModeChanged(int mode)
 {
   LOG_DEBUG("elevate mode changed: %d", mode);
@@ -135,61 +156,50 @@ void DaemonApp::handleRestartRequested()
 #endif
 }
 
-void DaemonApp::startAsync()
+void DaemonApp::init(int argc, char **argv)
 {
-#if SYSAPI_WIN32
+  bool isUninstalling = false;
-  m_watchdog->startAsync();
-#endif
-}
-
-int DaemonApp::init(int argc, char **argv)
-{
-  bool uninstall = false;
   try {
     // default log level to system setting.
     if (string logLevel = ARCH->setting("LogLevel"); logLevel != "")
       CLOG->setFilter(logLevel.c_str());
 
-    bool foreground = false;
-
     for (int i = 1; i < argc; ++i) {
       string arg(argv[i]);
 
       if (arg == "-f") {
-        foreground = true;
+        m_foreground = true;
       }
 #if SYSAPI_WIN32
       else if (arg == "--install" || arg == "/install") {
         LOG((CLOG_NOTE "installing windows daemon"));
-        uninstall = true;
         ARCH->installDaemon();
-        return kExitSuccess;
+        Q_EMIT serviceInstalled();
       } else if (arg == "--uninstall" || arg == "/uninstall") {
         LOG((CLOG_NOTE "uninstalling windows daemon"));
+        isUninstalling = true;
         ARCH->uninstallDaemon();
-        return kExitSuccess;
+        Q_EMIT serviceUninstalled();
       }
 #endif
       else {
         stringstream ss;
         ss << "Unrecognized argument: " << arg;
         foregroundError(ss.str().c_str());
-        return kExitArgs;
+        Q_EMIT fatalError();
       }
     }
 
-    if (!foreground) {
+    if (!m_foreground) {
 #if SYSAPI_WIN32
       // Only use MS debug outputter when the process is daemonized, since stdout won't be accessible
       // in that case, but is accessible when running in the foreground.
       CLOG->insert(new MSWindowsDebugOutputter()); // NOSONAR - Adopted by `Log`
 #endif
     }
-
-    return kExitSuccess;
   } catch (XArch &e) {
     std::string message = e.what();
-    if (uninstall && (message.find("The service has not been started") != std::string::npos)) {
+    if (isUninstalling && (message.find("The service has not been started") != std::string::npos)) {
       // TODO: if we're keeping this use error code instead (what is it?!).
       // HACK: this message happens intermittently, not sure where from but
       // it's quite misleading for the user. they thing something has gone
@@ -198,13 +208,13 @@ int DaemonApp::init(int argc, char **argv)
     } else {
       foregroundError(message.c_str());
     }
-    return kExitFailed;
+    Q_EMIT fatalError();
   } catch (std::exception &e) {
     foregroundError(e.what());
-    return kExitFailed;
+    Q_EMIT fatalError();
   } catch (...) {
     foregroundError("Unrecognized error.");
-    return kExitFailed;
+    Q_EMIT fatalError();
   }
 }
 

src/lib/deskflow/DaemonApp.h

@@ -11,7 +11,7 @@
 #include <memory>
 #include <string>
 
-#include <QCoreApplication>
+#include <QObject>
 
 #include "common/common.h"
 
@@ -20,6 +20,7 @@ class IEventQueue;
 class IpcLogOutputter;
 class FileLogOutputter;
 class QLocalServer;
+class QCoreApplication;
 
 namespace deskflow::core::ipc {
 class DaemonIpcServer;
@@ -31,15 +32,22 @@ class MSWindowsWatchdog;
 
 extern const char *const kLogFilename;
 
-class DaemonApp : public QCoreApplication
+class DaemonApp : public QObject
 {
+  Q_OBJECT
+
 public:
-  DaemonApp(IEventQueue *events, int argc, char **argv);
+  DaemonApp(IEventQueue *events);
   ~DaemonApp();
-  int init(int argc, char **argv);
+  void init(int argc, char **argv);
-  void startAsync();
+  void run();
   void mainLoop(bool logToFile, bool foreground = false);
 
+signals:
+  void fatalError();
+  void serviceInstalled();
+  void serviceUninstalled();
+
 private:
   void daemonize();
   void foregroundError(const char *message);
@@ -65,4 +73,5 @@ private:
   deskflow::core::ipc::DaemonIpcServer *m_ipcServer = nullptr;
   std::string m_command = "";
   int m_elevateMode = 0;
+  bool m_foreground = false;
 };

src/lib/deskflow/ipc/DaemonIpcServer.cpp

@@ -108,7 +108,7 @@ void DaemonIpcServer::processMessage(QLocalSocket *clientSocket, const QString &
       return;
     } else {
       LOG_DEBUG("ipc server got new elevate mode: %d", elevateMode);
-      Q_SIGNAL elevateModeChanged(elevateMode);
+      Q_EMIT elevateModeChanged(elevateMode);
       clientSocket->write(kAckMessage);
     }
   } else if (message.startsWith("command=")) {
@@ -118,12 +118,12 @@ void DaemonIpcServer::processMessage(QLocalSocket *clientSocket, const QString &
       clientSocket->write(kErrorMessage);
     } else {
       LOG_DEBUG("ipc server got new command: %s", command.toUtf8().constData());
-      Q_SIGNAL commandChanged(command);
+      Q_EMIT commandChanged(command);
       clientSocket->write(kAckMessage);
     }
   } else if (message == "restart") {
     LOG_DEBUG("ipc server got restart message");
-    Q_SIGNAL restartRequested();
+    Q_EMIT restartRequested();
     clientSocket->write(kAckMessage);
   } else {
     LOG_WARN("ipc server got unknown message: %s", message.toUtf8().constData());