Add support for running in single instance mode on Linux and Windows

Prevent reopening already opened repo on IPC call

CMakeLists.txt

@@ -49,7 +49,7 @@ set(QT_MODULES
   Test
 )
 
-if(APPLE)
+if(UNIX)
   set(QT_MODULES ${QT_MODULES} DBus)
 endif()
 

src/app/Application.cpp

@@ -14,6 +14,7 @@
 #include "ui/MainWindow.h"
 #include "ui/MenuBar.h"
 #include "ui/RepoView.h"
+#include "ui/TabWidget.h"
 #include "update/Updater.h"
 #include <QCloseEvent>
 #include <QCommandLineParser>
@@ -33,13 +34,17 @@
 #include <QUrlQuery>
 #include <QUuid>
 
-#if defined(Q_OS_MAC)
+#if defined(Q_OS_LINUX)
+#include <QtDBus/QtDBus>
+
+#elif defined(Q_OS_MAC)
 #include <unistd.h>
 
 #elif defined(Q_OS_WIN)
 #include <windows.h>
 #include <dbghelp.h>
 #include <strsafe.h>
+#include <QWindow>
 
 static LPTOP_LEVEL_EXCEPTION_FILTER defaultFilter = nullptr;
 
@@ -274,6 +279,178 @@ bool Application::restoreWindows()
   return MainWindow::restoreWindows();
 }
 
+static MainWindow *openOrSwitch(QDir repo)
+{
+  repo.makeAbsolute();
+
+  QList<MainWindow *> windows = MainWindow::windows();
+  for (MainWindow *window : windows) {
+    TabWidget *tabs = window->tabWidget();
+
+    for (int i = 0; i < tabs->count(); ++i) {
+      RepoView *view = (RepoView *)tabs->widget(i);
+      QDir openRepo = QDir(view->repo().workdir().path());
+
+      if (openRepo == repo) {
+        tabs->setCurrentIndex(i);
+        return window;
+      }
+    }
+  }
+
+  return MainWindow::open(repo.path(), true);
+}
+
+#if defined(Q_OS_LINUX)
+#define DBUS_SERVICE_NAME "com.github.Murmele.Gittyup"
+#define DBUS_INTERFACE_NAME "com.github.Murmele.Gittyup.Application"
+#define DBUS_OBJECT_PATH "/com/github/Murmele/Gittyup/Application"
+
+DBusGittyup::DBusGittyup(QObject *parent): QObject(parent)
+{
+}
+
+void DBusGittyup::openRepository(const QString &repo)
+{
+  openOrSwitch(QDir(repo));
+}
+
+void DBusGittyup::openAndFocusRepository(const QString &repo)
+{
+  openOrSwitch(QDir(repo))->activateWindow();
+}
+
+void DBusGittyup::setFocus()
+{
+  MainWindow::activeWindow()->activateWindow();
+}
+
+#elif defined(Q_OS_WIN)
+#define COPYDATA_WINDOW_TITLE "Gittyup WM_COPYDATA receiver 16b8b3f6-6446-4fa7-8c72-53c25b1f206c"
+enum CopyDataCommand
+{
+  Focus = 0,
+  FocusAndOpen = 1
+};
+
+namespace
+{
+  // Helper window class for receiving IPC messages
+  class CopyDataWindow: public QWindow
+  {
+  public:
+    CopyDataWindow()
+    {
+      setTitle(COPYDATA_WINDOW_TITLE);
+    }
+
+  protected:
+    virtual bool nativeEvent(const QByteArray &eventType, void *message, long *result) Q_DECL_OVERRIDE
+    {
+      MSG *msg = (MSG*) message;
+
+      if (msg->message == WM_COPYDATA) {
+        COPYDATASTRUCT *cds = (COPYDATASTRUCT*) msg->lParam;
+
+        switch (cds->dwData) {
+          case CopyDataCommand::Focus:
+            MainWindow::activeWindow()->activateWindow();
+            break;
+
+          case CopyDataCommand::FocusAndOpen:
+            if (cds->cbData % 2 == 0) {
+              QString repo = QString::fromUtf16((const char16_t*) cds->lpData, cds->cbData / 2);
+              openOrSwitch(QDir(repo));
+
+              MainWindow::activeWindow()->activateWindow();
+            }
+            break;
+        }
+
+        return true;
+      }
+
+      return QWindow::nativeEvent(eventType, message, result);
+    }
+  };
+}
+#endif
+
+bool Application::runSingleInstance()
+{
+  if (Settings::instance()->value("singleInstance").toBool()) {
+#if defined(Q_OS_LINUX)
+    QDBusConnection bus = QDBusConnection::sessionBus();
+
+    if (bus.isConnected()) {
+      QDBusInterface masterInstance(DBUS_SERVICE_NAME, DBUS_OBJECT_PATH, DBUS_INTERFACE_NAME, bus);
+
+      // Is another instance running on the current DBus session bus?
+      if (masterInstance.isValid()) {
+        if (!mPositionalArguments.isEmpty())
+          masterInstance.call("openAndFocusRepository", QDir(mPositionalArguments.first()).absolutePath());
+        return true;
+      }
+    }
+
+#elif defined(Q_OS_WIN)
+    HWND handle = FindWindowA(nullptr, COPYDATA_WINDOW_TITLE);
+    // Is another instance running in the current session?
+    if (handle != nullptr) {
+      QWindow sender;
+
+      COPYDATASTRUCT cds;
+
+      if (mPositionalArguments.isEmpty()) {
+        cds.dwData = CopyDataCommand::Focus;
+        cds.cbData = 0;
+        cds.lpData = nullptr;
+
+        SendMessage(handle, WM_COPYDATA, sender.winId(), (LPARAM) &cds);
+
+      } else {
+        QString arg = QDir(mPositionalArguments.first()).absolutePath();
+
+        cds.dwData = CopyDataCommand::FocusAndOpen;
+        cds.cbData = arg.length() * 2;
+        cds.lpData = (LPVOID) arg.utf16();
+
+        SendMessage(handle, WM_COPYDATA, sender.winId(), (LPARAM) &cds);
+      }
+
+      return true;
+    }
+
+#endif
+  }
+
+#ifndef Q_OS_MAC
+  registerService();
+#endif
+  return false;
+}
+
+#ifndef Q_OS_MAC
+void Application::registerService()
+{
+#if defined(Q_OS_LINUX)
+  QDBusConnection bus = QDBusConnection::sessionBus();
+
+  if (!bus.isConnected())
+    return;
+
+  if (!bus.registerService(DBUS_SERVICE_NAME))
+    return;
+
+  bus.registerObject(DBUS_OBJECT_PATH, DBUS_INTERFACE_NAME, new DBusGittyup(), QDBusConnection::ExportScriptableSlots);
+
+#elif defined(Q_OS_WIN)
+  CopyDataWindow *receiver = new CopyDataWindow();
+  receiver->winId();
+#endif
+}
+#endif
+
 Theme *Application::theme()
 {
   return static_cast<Application *>(instance())->mTheme.data();

src/app/Application.h

@@ -27,6 +27,7 @@ public:
 
   void autoUpdate();
   bool restoreWindows();
+  bool runSingleInstance();
 
   static Theme *theme();
 
@@ -42,4 +43,19 @@ private:
   QStringList mPositionalArguments;
 };
 
+#ifdef Q_OS_LINUX
+class DBusGitAhead: public QObject
+{
+  Q_OBJECT
+
+public:
+  DBusGitAhead(QObject *parent = nullptr);
+
+public slots:
+  Q_SCRIPTABLE void openRepository(const QString &repo);
+  Q_SCRIPTABLE void openAndFocusRepository(const QString &repo);
+  Q_SCRIPTABLE void setFocus();
+};
+#endif
+
 #endif

src/app/CMakeLists.txt

@@ -52,6 +52,10 @@ add_library(app
   ${THEME_IMPL_FILE}
 )
 
+if(UNIX AND NOT APPLE)
+  set_target_properties(app PROPERTIES AUTOMOC ON)
+endif()
+
 target_compile_definitions(app
   PUBLIC
     GITTYUP_NAME="${GITTYUP_NAME}"
@@ -72,6 +76,12 @@ set_target_properties(app PROPERTIES
   AUTOMOC ON
 )
 
+if(UNIX AND NOT APPLE)
+  target_link_libraries(app
+    Qt5::DBus
+  )
+endif()
+
 # Add main executable.
 add_executable(gittyup WIN32 MACOSX_BUNDLE
   Gittyup.cpp

src/app/Gittyup.cpp

@@ -16,6 +16,10 @@ int main(int argc, char *argv[])
   Application::setAttribute(Qt::AA_UseHighDpiPixmaps);
   Application app(argc, argv, true);
 
+  // Check if only one running instance is allowed and already running
+  if (app.runSingleInstance())
+    return 0;
+
   // Restore windows before checking for updates so that
   // the update dialog pops up on top of the other windows.
   if (!app.restoreWindows())

src/dialogs/SettingsDialog.cpp

@@ -125,6 +125,9 @@ public:
       AboutDialog::openSharedInstance(AboutDialog::Privacy);
     });
 
+    mSingleInstance = new QCheckBox(
+      tr("Only allow a single running instance"), this);
+
     QFormLayout *form = new QFormLayout;
     form->addRow(tr("User name:"), mName);
     form->addRow(tr("User email:"), mEmail);
@@ -136,6 +139,10 @@ public:
     form->addRow(tr("Credentials:"), mStoreCredentials);
     form->addRow(QString(), privacy);
 
+#if defined(Q_OS_LINUX) || defined(Q_OS_WIN)
+    form->addRow(tr("Single instance:"), mSingleInstance);
+#endif
+
     QVBoxLayout *layout = new QVBoxLayout(this);
     layout->setContentsMargins(16,12,16,12);
     layout->addLayout(form);
@@ -186,6 +193,10 @@ public:
       Settings::instance()->setValue("credential/store", checked);
       delete CredentialHelper::instance();
     });
+
+    connect(mSingleInstance, &QCheckBox::toggled, [](bool checked) {
+      Settings::instance()->setValue("singleInstance", checked);
+    });
   }
 
   void init()
@@ -208,6 +219,8 @@ public:
 
     mNoTranslation->setChecked(settings->value("translation/disable").toBool());
     mStoreCredentials->setChecked(settings->value("credential/store").toBool());
+
+    mSingleInstance->setChecked(settings->value("singleInstance").toBool());
   }
 
 private:
@@ -221,6 +234,7 @@ private:
   QCheckBox *mAutoPrune;
   QCheckBox *mNoTranslation;
   QCheckBox *mStoreCredentials;
+  QCheckBox *mSingleInstance;
 };
 
 class ToolsPanel : public QWidget