Kdsingleapplication as SingleApplication alternative (flameshot-org#4032)

* Enable SingleApplication again (compile flag; enabled by default)

* Enable SingleApplication again (compile flag; enabled by default)

* Add KDSingleApplication as SingleApplication alternative

* Cleanup: Removed /external/ subfolder

* Update CMakeLists.txt

* Remove SingleApplication; enable KDSingleApplication by default

Author: ElTh0r0

CMakeLists.txt

@@ -89,7 +89,7 @@ set(RUN_IN_PLACE
 option(FLAMESHOT_DEBUG_CAPTURE "Enable mode to make debugging easier" OFF)
 option(USE_MONOCHROME_ICON "Build using monochrome icon as default" OFF)
 option(GENERATE_TS "Regenerate translation source files" OFF)
-option(USE_SINGLEAPPLICATION "Use SingleApplication library" ON)
+option(USE_KDSINGLEAPPLICATION "Use KDSingleApplication library" ON)
 option(USE_LAUNCHER_ABSOLUTE_PATH "Use absolute path for the desktop launcher" ON)
 option(USE_WAYLAND_CLIPBOARD "USE KF Gui Wayland Clipboard" OFF)
 option(DISABLE_UPDATE_CHECKER "Disable check for updates" OFF)
@@ -123,20 +123,18 @@ enable_sanitizers(project_options)
 
 # allow for static analysis options include(cmake/StaticAnalyzers.cmake)
 
-if(USE_SINGLEAPPLICATION)
-  set(QAPPLICATION_CLASS
-          QApplication
-          CACHE STRING "Inheritance class for SingleApplication")
+if (USE_KDSINGLEAPPLICATION)
+  set(KDSingleApplication_EXAMPLES OFF CACHE BOOL "Don't build the examples")
+  set(KDSingleApplication_STATIC ON CACHE BOOL "Build static versions of the libraries")
 
   FetchContent_Declare(
-      singleApplication
-      GIT_REPOSITORY https://github.com/itay-grudev/SingleApplication.git
-      GIT_TAG v3.5.2
+      kdsingleApplication
+      GIT_REPOSITORY https://github.com/KDAB/KDSingleApplication.git
+      GIT_TAG v1.2.0
   )
-  FetchContent_MakeAvailable(SingleApplication)
+  FetchContent_MakeAvailable(KDSingleApplication)
 endif()
 
-
 option(BUILD_STATIC_LIBS ON)
 option(BUILD_SHARED_LIBS OFF)
 

src/CMakeLists.txt

@@ -214,12 +214,13 @@ target_link_libraries(
         QtColorWidgets
 )
 
-if (USE_SINGLEAPPLICATION)
-  message(STATUS "SingleApplication is used!")
-  add_compile_definitions(USE_SINGLEAPPLICATION=1)
+if (USE_KDSINGLEAPPLICATION)
+  message(STATUS "KDSingleApplication is used!")
+  add_compile_definitions(USE_KDSINGLEAPPLICATION=1)
+
   target_link_libraries(
           flameshot
-          SingleApplication::SingleApplication
+          kdsingleapplication
   )
 endif()
 

src/main.cpp

@@ -1,8 +1,8 @@
 // SPDX-License-Identifier: GPL-3.0-or-later
 // SPDX-FileCopyrightText: 2017-2019 Alejandro Sirgo Rica & Contributors
 
-#ifdef USE_SINGLEAPPLICATION
-#include "singleapplication.h"
+#ifdef USE_KDSINGLEAPPLICATION
+#include "kdsingleapplication.h"
 #endif
 
 #include "abstractlogger.h"
@@ -140,10 +140,16 @@ int main(int argc, char* argv[])
 
     // no arguments, just launch Flameshot
     if (argc == 1) {
-#ifdef USE_SINGLEAPPLICATION
-        SingleApplication app(argc, argv);
-#else
         QApplication app(argc, argv);
+
+#ifdef USE_KDSINGLEAPPLICATION
+        KDSingleApplication kdsa(QStringLiteral("flameshot"));
+
+        if (!kdsa.isPrimaryInstance()) {
+            // AbstractLogger::warning()
+            //  << QStringLiteral("Closing second Flameshot instance!");
+            return 0; // Quit
+        }
 #endif
 
         configureApp(true);