Terminate Syncthing gracefully via REST-API on non-UNIX platforms

If there's a configured and local Syncthing connection and we're on a
non-UNIX platform which doesn't support SIGTERM (basically Windows) it
makes sense to use the REST-API instead. That's likely better than just
terminating the process forcefully.

This doesn't cover the stop button within the launcher settings yet because
from this context is isn't clear which connection is relevant as there can
be multiple tray icons/widgets but only one settings page.

connector/syncthingprocess.cpp

@@ -1,5 +1,7 @@
 #include "./syncthingprocess.h"
 
+#include <syncthingconnector/syncthingconnection.h>
+
 #include <QTimer>
 
 #ifdef LIB_SYNCTHING_CONNECTOR_BOOST_PROCESS
@@ -185,9 +187,10 @@ QStringList SyncthingProcess::splitArguments(const QString &arguments)
 }
 
 /*!
- * \brief Stops the currently running process. If it has been stopped, starts the specified \a program with the specified \a arguments.
+ * \brief Stops the currently running process gracefully. If it has been stopped, starts the specified \a program with the specified \a arguments.
+ * \sa See stopSyncthing() for details about \a currentConnection.
  */
-void SyncthingProcess::restartSyncthing(const QString &program, const QStringList &arguments)
+void SyncthingProcess::restartSyncthing(const QString &program, const QStringList &arguments, SyncthingConnection *currentConnection)
 {
     if (!isRunning()) {
         startSyncthing(program, arguments);
@@ -195,9 +198,7 @@ void SyncthingProcess::restartSyncthing(const QString &program, const QStringLis
     }
     m_program = program;
     m_arguments = arguments;
-    m_manuallyStopped = true;
-    m_killTimer.start();
-    terminate();
+    stopSyncthing(currentConnection);
 }
 
 /*!
@@ -215,11 +216,22 @@ void SyncthingProcess::startSyncthing(const QString &program, const QStringList
 
 /*!
  * \brief Stops the currently running process gracefully. If it doesn't stop after 3 seconds, attempts to kill the process.
+ * \remarks
+ * If graceful stopping is not possible (under Windows) the process is attempted to be stopped via the REST-API using \a currentConnection.
+ * This is however only considered, if \a currentConnection is configured and a local connection.
  */
-void SyncthingProcess::stopSyncthing()
+void SyncthingProcess::stopSyncthing(SyncthingConnection *currentConnection)
 {
     m_manuallyStopped = true;
     m_killTimer.start();
+#ifdef PLATFORM_UNIX
+    Q_UNUSED(currentConnection)
+#else
+    if (currentConnection && !currentConnection->syncthingUrl().isEmpty() && !currentConnection->apiKey().isEmpty() && currentConnection->isLocal()) {
+        currentConnection->shutdown();
+        return;
+    }
+#endif
     terminate();
 }
 

connector/syncthingprocess.h

@@ -15,6 +15,7 @@
 
 namespace Data {
 
+class SyncthingConnection;
 #ifdef LIB_SYNCTHING_CONNECTOR_BOOST_PROCESS
 struct SyncthingProcessInternalData;
 struct SyncthingProcessIOHandler;
@@ -55,9 +56,9 @@ public:
 #endif
 
 public Q_SLOTS:
-    void restartSyncthing(const QString &program, const QStringList &arguments);
+    void restartSyncthing(const QString &program, const QStringList &arguments, SyncthingConnection *currentConnection = nullptr);
     void startSyncthing(const QString &program, const QStringList &arguments);
-    void stopSyncthing();
+    void stopSyncthing(SyncthingConnection *currentConnection = nullptr);
     void killSyncthing();
 #ifdef LIB_SYNCTHING_CONNECTOR_BOOST_PROCESS
     void terminate();

tray/gui/traywidget.cpp

@@ -682,7 +682,7 @@ void TrayWidget::toggleRunning()
     case StartStopButtonTarget::Launcher:
         if (auto *const launcher = SyncthingLauncher::mainInstance()) {
             if (launcher->isRunning()) {
-                launcher->terminate();
+                launcher->terminate(&m_connection);
             } else {
                 launcher->launch(Settings::values().launcher);
             }

widgets/misc/syncthinglauncher.cpp

@@ -153,11 +153,11 @@ void SyncthingLauncher::launch(const LibSyncthing::RuntimeOptions &runtimeOption
 }
 #endif
 
-void SyncthingLauncher::terminate()
+void SyncthingLauncher::terminate(SyncthingConnection *relevantConnection)
 {
     if (m_process.isRunning()) {
         m_manuallyStopped = true;
-        m_process.stopSyncthing();
+        m_process.stopSyncthing(relevantConnection);
     } else {
         tearDownLibSyncthing();
     }

widgets/misc/syncthinglauncher.h

@@ -18,6 +18,8 @@ struct Launcher;
 
 namespace Data {
 
+class SyncthingConnection;
+
 class SYNCTHINGWIDGETS_EXPORT SyncthingLauncher : public QObject {
     Q_OBJECT
     Q_PROPERTY(bool running READ isRunning NOTIFY runningChanged)
@@ -57,7 +59,7 @@ Q_SIGNALS:
 public Q_SLOTS:
     void launch(const QString &program, const QStringList &arguments);
     void launch(const Settings::Launcher &launcherSettings);
-    void terminate();
+    void terminate(SyncthingConnection *relevantConnection = nullptr);
     void kill();
     void tearDownLibSyncthing();