Rework NSM code, actually works now :)

source/backend/CarlaBackend.h

@@ -914,29 +914,35 @@ typedef enum {
      */
     ENGINE_CALLBACK_SAMPLE_RATE_CHANGED = 34,
 
+    /*!
+     * NSM callback.
+     * (Work in progress, values are not defined yet)
+     */
+    ENGINE_CALLBACK_NSM = 35,
+
     /*!
      * Idle frontend.
      * This is used by the engine during long operations that might block the frontend,
      * giving it the possibility to idle while the operation is still in place.
      */
-    ENGINE_CALLBACK_IDLE = 35,
+    ENGINE_CALLBACK_IDLE = 36,
 
     /*!
      * Show a message as information.
      * @a valueStr The message
      */
-    ENGINE_CALLBACK_INFO = 36,
+    ENGINE_CALLBACK_INFO = 37,
 
     /*!
      * Show a message as an error.
      * @a valueStr The message
      */
-    ENGINE_CALLBACK_ERROR = 37,
+    ENGINE_CALLBACK_ERROR = 38,
 
     /*!
      * The engine has crashed or malfunctioned and will no longer work.
      */
-    ENGINE_CALLBACK_QUIT = 38
+    ENGINE_CALLBACK_QUIT = 39
 
 } EngineCallbackOpcode;
 
@@ -1030,42 +1036,37 @@ typedef enum {
      */
     ENGINE_OPTION_AUDIO_DEVICE = 12,
 
-    /*!
-     * Set data needed for NSM support.
-     */
-    ENGINE_OPTION_NSM_INIT = 13,
-
     /*!
      * Set path used for a specific plugin type.
      * Uses value as the plugin format, valueStr as actual path.
      * @see PluginType
      */
-    ENGINE_OPTION_PLUGIN_PATH = 14,
+    ENGINE_OPTION_PLUGIN_PATH = 13,
 
     /*!
      * Set path to the binary files.
      * Default unset.
      * @note Must be set for plugin and UI bridges to work
      */
-    ENGINE_OPTION_PATH_BINARIES = 15,
+    ENGINE_OPTION_PATH_BINARIES = 14,
 
     /*!
      * Set path to the resource files.
      * Default unset.
      * @note Must be set for some internal plugins to work
      */
-    ENGINE_OPTION_PATH_RESOURCES = 16,
+    ENGINE_OPTION_PATH_RESOURCES = 15,
 
     /*!
      * Prevent bad plugin and UI behaviour.
      * @note: Linux only
      */
-    ENGINE_OPTION_PREVENT_BAD_BEHAVIOUR = 17,
+    ENGINE_OPTION_PREVENT_BAD_BEHAVIOUR = 16,
 
     /*!
      * Set frontend winId, used to define as parent window for plugin UIs.
      */
-    ENGINE_OPTION_FRONTEND_WIN_ID = 18
+    ENGINE_OPTION_FRONTEND_WIN_ID = 17
 
 } EngineOption;
 

source/backend/CarlaHost.h

@@ -899,6 +899,16 @@ CARLA_EXPORT const char* carla_get_library_filename();
  */
 CARLA_EXPORT const char* carla_get_library_folder();
 
+/*!
+ * Initialize NSM (announce).
+ */
+CARLA_EXPORT bool carla_nsm_init(int pid, const char* executableName);
+
+/*!
+ * Allow NSM callbacks.
+ */
+CARLA_EXPORT void carla_nsm_ready();
+
 /** @} */
 
 #endif /* CARLA_HOST_H_INCLUDED */

source/backend/CarlaStandalone.cpp

@@ -89,257 +89,333 @@ static CarlaBackendStandalone gStandalone;
 #define NSM_API_VERSION_MAJOR 1
 #define NSM_API_VERSION_MINOR 2
 
-//#define NSM_CLIENT_FEATURES ":switch:optional-gui:"
 #define NSM_CLIENT_FEATURES ":switch:"
+//#define NSM_CLIENT_FEATURES ":switch:optional-gui:"
 
 class CarlaNSM
 {
 public:
     CarlaNSM() noexcept
-        : fOscServer(nullptr),
-          fClientId(),
+        : fOscAddress(nullptr),
+          fOscServer(nullptr),
+          fOscServerThread(nullptr),
           fProjectPath(),
           fHasBroadcast(false),
-          fHasShowHideUI(false) {}
+          fHasOptionalGui(false),
+          fHasServerControl(false),
+          fStarted() {}
 
     ~CarlaNSM()
     {
-        if (fOscServer != nullptr)
+        if (fOscServerThread != nullptr)
         {
-            lo_server_del_method(fOscServer, "/reply", "ssss");
-            lo_server_del_method(fOscServer, "/nsm/client/open", "sss");
-            lo_server_del_method(fOscServer, "/nsm/client/save", "");
-            //lo_server_del_method(fOscServer, "/nsm/client/show_optional_gui", "");
-            //lo_server_del_method(fOscServer, "/nsm/client/hide_optional_gui", "");
-            lo_server_free(fOscServer);
+            lo_server_thread_stop(fOscServerThread);
+            lo_server_thread_free(fOscServerThread);
+            fOscServerThread = nullptr;
             fOscServer = nullptr;
         }
+
+        if (fOscAddress != nullptr)
+        {
+            lo_address_free(fOscAddress);
+            fOscAddress = nullptr;
+        }
     }
 
-    void announce(const int pid, const char* const initName)
+    bool announce(const int pid, const char* const executableName)
     {
+        CARLA_SAFE_ASSERT_RETURN(pid != 0, false);
+        CARLA_SAFE_ASSERT_RETURN(executableName != nullptr && executableName[0] != '\0', false);
+
         const char* const NSM_URL(std::getenv("NSM_URL"));
 
         if (NSM_URL == nullptr)
-            return;
+            return false;
 
         const lo_address addr = lo_address_new_from_url(NSM_URL);
-        CARLA_SAFE_ASSERT_RETURN(addr != nullptr,);
+        CARLA_SAFE_ASSERT_RETURN(addr != nullptr, false);
 
         const int proto = lo_address_get_protocol(addr);
 
-        if (fOscServer == nullptr)
+        if (fOscServerThread == nullptr)
         {
             // create new OSC server
-            fOscServer = lo_server_new_with_proto(nullptr, proto, _error_handler);
-
-            // register message handlers and start OSC thread
-            lo_server_add_method(fOscServer, "/reply",           "ssss", _reply_handler, this);
-            lo_server_add_method(fOscServer, "/nsm/client/open", "sss",  _open_handler,  this);
-            lo_server_add_method(fOscServer, "/nsm/client/save", "",     _save_handler,  this);
-            //lo_server_add_method(fOscServer, "/nsm/client/show_optional_gui", "", _show_gui_handler, this);
-            //lo_server_add_method(fOscServer, "/nsm/client/hide_optional_gui", "", _hide_gui_handler, this);
-            // /nsm/client/session_is_loaded
+            fOscServerThread = lo_server_thread_new_with_proto(nullptr, proto, _osc_error_handler);
+            CARLA_SAFE_ASSERT_RETURN(fOscServerThread != nullptr, false);
+
+            // register message handlers
+            lo_server_thread_add_method(fOscServerThread, "/error",                       "sis",    _error_handler,     this);
+            lo_server_thread_add_method(fOscServerThread, "/reply",                       "ssss",   _reply_handler,     this);
+            lo_server_thread_add_method(fOscServerThread, "/nsm/client/open",             "sss",    _open_handler,      this);
+            lo_server_thread_add_method(fOscServerThread, "/nsm/client/save",              "",      _save_handler,      this);
+            lo_server_thread_add_method(fOscServerThread, "/nsm/client/session_is_loaded", "",      _loaded_handler,    this);
+            lo_server_thread_add_method(fOscServerThread, "/nsm/client/show_optional_gui", "",      _show_gui_handler,  this);
+            lo_server_thread_add_method(fOscServerThread, "/nsm/client/hide_optional_gui", "",      _hide_gui_handler,  this);
+            lo_server_thread_add_method(fOscServerThread, nullptr,                         nullptr, _broadcast_handler, this);
+
+            fOscServer = lo_server_thread_get_server(fOscServerThread);
         }
 
 #ifndef BUILD_ANSI_TEST
         lo_send_from(addr, fOscServer, LO_TT_IMMEDIATE, "/nsm/server/announce", "sssiii",
-                     "Carla", NSM_CLIENT_FEATURES, initName, NSM_API_VERSION_MAJOR, NSM_API_VERSION_MINOR, pid);
+                     "Carla", NSM_CLIENT_FEATURES, executableName, NSM_API_VERSION_MAJOR, NSM_API_VERSION_MINOR, pid);
 #endif
 
         lo_address_free(addr);
+
+        return true;
     }
 
-    void idle() noexcept
+    void start()
     {
-        if (fOscServer == nullptr)
-            return;
+        CARLA_SAFE_ASSERT_RETURN(fOscServerThread != nullptr,);
+        CARLA_SAFE_ASSERT_RETURN(! fStarted,);
 
-        for (;;)
-        {
-            try {
-                if (lo_server_recv_noblock(fOscServer, 0) == 0)
-                    break;
-            } CARLA_SAFE_EXCEPTION_CONTINUE("NSM OSC idle")
-        }
+        fStarted = true;
+        lo_server_thread_start(fOscServerThread);
+    }
+
+    static CarlaNSM& getInstance()
+    {
+        static CarlaNSM sInstance;
+        return sInstance;
     }
 
 protected:
-    int handleReply(const char* const path, const char* const types, lo_arg** const argv, const int argc, const lo_message msg)
+    int handleError(const char* const method, const int code, const char* const message)
     {
-        carla_debug("CarlaNSM::handleReply(%s, %i, %p, %s, %p)", path, argc, argv, types, msg);
+        carla_stdout("CarlaNSM::handleError(\"%s\", %i, \"%s\")", method, code, message);
 
-        const char* const method   = &argv[0]->s;
-        const char* const message  = &argv[1]->s;
-        const char* const smName   = &argv[2]->s;
-        const char* const features = &argv[3]->s;
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 0, code, 0.0f, message);
 
-        CARLA_SAFE_ASSERT_RETURN(std::strcmp(method, "/nsm/server/announce") == 0, 0);
+        return 1;
 
-        fHasBroadcast  = std::strstr(features, ":broadcast:") != nullptr;
-        fHasShowHideUI = std::strstr(features, ":optional-gui:") != nullptr;
+        // may be unused
+        (void)method;
+    }
 
-        carla_stdout("'%s' started: %s", smName, message);
+    int handleReply(const char* const method, const char* const message, const char* const smName, const char* const features,
+                    const lo_message msg)
+    {
+        CARLA_SAFE_ASSERT_RETURN(fOscServerThread != nullptr, 1);
+        carla_stdout("CarlaNSM::handleReply(\"%s\", \"%s\", \"%s\", \"%s\")", method, message, smName, features);
 
-        // TODO: send callback, disable open+save etc
+        if (std::strcmp(method, "/nsm/server/announce") == 0)
+        {
+            char* const addressURL(lo_address_get_url(lo_message_get_source(msg)));
+            CARLA_SAFE_ASSERT_RETURN(addressURL != nullptr, 0);
 
-        return 0;
+            if (fOscAddress != nullptr)
+                lo_address_free(fOscAddress);
 
-#ifndef DEBUG
-        // unused
-        (void)path; (void)types; (void)argc; (void)msg;
-#endif
-    }
+            fOscAddress = lo_address_new_from_url(addressURL);
+            CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 0);
 
-    // FIXME
-    int handleOpen(const char* const path, const char* const types, lo_arg** const argv, const int argc, const lo_message msg)
-    {
-        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 0);
-        carla_debug("CarlaNSM::handleOpen(\"%s\", \"%s\", %p, %i, %p)", path, types, argv, argc, msg);
+            fHasBroadcast     = std::strstr(features, ":broadcast:")      != nullptr;
+            fHasOptionalGui   = std::strstr(features, ":optional-gui:")   != nullptr;
+            fHasServerControl = std::strstr(features, ":server_control:") != nullptr;
 
-        const char* const projectPath = &argv[0]->s;
-        //const char* const displayName = &argv[1]->s;
-        const char* const clientId    = &argv[2]->s;
+            carla_stdout("Carla started via '%s', message: %s", smName, message);
 
-        if (! carla_is_engine_running())
-        {
-#ifndef BUILD_BRIDGE
-            gStandalone.engineOptions.processMode   = CB::ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS;
-            gStandalone.engineOptions.transportMode = CB::ENGINE_TRANSPORT_MODE_JACK;
-#endif
+            if (gStandalone.engineCallback != nullptr)
+                gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 1, 0, 0.0f, smName);
 
-            carla_engine_init("JACK", clientId);
+            // UI starts visible
+            lo_send_from(fOscAddress, fOscServer, LO_TT_IMMEDIATE, "/nsm/client/gui_is_shown", "");
         }
         else
         {
-            CARLA_SAFE_ASSERT_RETURN(gStandalone.engine != nullptr, 0);
-
-            for (uint i=0, count=gStandalone.engine->getCurrentPluginCount(); i < count; ++i)
-                gStandalone.engine->removePlugin(i);
+            carla_stdout("Got unknown NSM reply method '%s'", method);
         }
 
-        fClientId = clientId;
+        return 0;
+    }
+
+    int handleOpen(const char* const projectPath, const char* const displayName, const char* const clientNameId)
+    {
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        carla_stdout("CarlaNSM::handleOpen(\"%s\", \"%s\", \"%s\")", projectPath, displayName, clientNameId);
+
+        if (carla_is_engine_running())
+            carla_engine_close();
+
+        carla_engine_init("JACK", clientNameId);
 
         fProjectPath  = projectPath;
         fProjectPath += ".carxp";
 
-        CARLA_SAFE_ASSERT_RETURN(gStandalone.engine != nullptr, 0);
+        using namespace juce;
 
-        if (juce::File(fProjectPath.buffer()).existsAsFile())
-            gStandalone.engine->loadProject(fProjectPath);
+        const String jfilename = String(CharPointer_UTF8(fProjectPath));
 
-#ifndef BUILD_ANSI_TEST
-        lo_send_from(lo_message_get_source(msg), fOscServer, LO_TT_IMMEDIATE, "/reply", "ss", "/nsm/client/open", "OK");
-#endif
+        if (File(jfilename).existsAsFile())
+            carla_load_project(fProjectPath);
 
-#if 0
-        if (fHasBroadcast)
-        {
-            char* const url = lo_server_get_url(fOscServer);
+        lo_send_from(fOscAddress, fOscServer, LO_TT_IMMEDIATE, "/reply", "ss", "/nsm/client/open", "OK");
 
-            lo_send(lo_message_get_source(msg), "/nsm/server/broadcast", "sssss",
-                            "/non/hello", url, "Carla", CARLA_VERSION_STRING, clientId);
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 2, 0, 0.0f, projectPath);
 
-            //lo_send_from(lo_message_get_source(msg), fOscServer, LO_TT_IMMEDIATE, "/nsm/server/broadcast", "sssss"
-            //             "/non/hello", url, "Carla", CARLA_VERSION_STRING, clientId);
+        return 0;
+    }
 
-            lo_send(lo_message_get_source(msg), "/signal/created", "ssfff", "/path/somewhere", true ? "in" : "out", 0.0f, 1.0f, 0.5f);
+    int handleSave()
+    {
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fProjectPath.isNotEmpty(), 0);
+        carla_stdout("CarlaNSM::handleSave()");
 
-            std::free(url);
+        carla_save_project(fProjectPath);
 
-            carla_stdout("Broadcast sent!");
-        }
-        else
-            carla_stdout("Broadcast NOT NOT NOT sent!");
-#endif
+        lo_send_from(fOscAddress, fOscServer, LO_TT_IMMEDIATE, "/reply", "ss", "/nsm/client/save", "OK");
+
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 3, 0, 0.0f, nullptr);
 
         return 0;
+    }
 
-#ifndef DEBUG
-        // unused
-        (void)path; (void)types; (void)argc; (void)msg;
-#endif
+    int handleSessionIsLoaded()
+    {
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        carla_stdout("CarlaNSM::handleSessionIsLoaded()");
+
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 4, 0, 0.0f, nullptr);
+
+        return 0;
     }
 
-    int handleSave(const char* const path, const char* const types, lo_arg** const argv, const int argc, const lo_message msg)
+    int handleShowOptionalGui()
     {
-        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 0);
-        CARLA_SAFE_ASSERT_RETURN(gStandalone.engine != nullptr, 0);
-        CARLA_SAFE_ASSERT_RETURN(fProjectPath.isNotEmpty(), 0);
-        carla_debug("CarlaNSM::handleSave(\"%s\", \"%s\", %p, %i, %p)", path, types, argv, argc, msg);
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        carla_stdout("CarlaNSM::handleShowOptionalGui()");
 
-        gStandalone.engine->saveProject(fProjectPath);
+        lo_send_from(fOscAddress, fOscServer, LO_TT_IMMEDIATE, "/nsm/client/gui_is_shown", "");
 
-#ifndef BUILD_ANSI_TEST
-        lo_send_from(lo_message_get_source(msg), fOscServer, LO_TT_IMMEDIATE, "/reply", "ss", "/nsm/client/save", "OK");
-#endif
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 5, 0, 0.0f, nullptr);
 
         return 0;
+    }
 
-#ifndef DEBUG
-        // unused
-        (void)path; (void)types; (void)argv; (void)argc; (void)msg;
-#endif
+    int handleHideOptionalGui()
+    {
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        carla_stdout("CarlaNSM::handleHideOptionalGui()");
+
+        lo_send_from(fOscAddress, fOscServer, LO_TT_IMMEDIATE, "/nsm/client/gui_is_hidden", "");
+
+        if (gStandalone.engineCallback != nullptr)
+            gStandalone.engineCallback(gStandalone.engineCallbackPtr, CB::ENGINE_CALLBACK_NSM, 0, 6, 0, 0.0f, nullptr);
+
+        return 0;
     }
 
-#if 0
-    int handleShowHideGui(const lo_message msg, const bool show)
+    int handleBroadcast(const char* const types, lo_arg** const argv, const int argc)
     {
-        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 0);
-        CARLA_SAFE_ASSERT_RETURN(gStandalone.engine != nullptr, 0);
-        //CARLA_SAFE_ASSERT_RETURN(gStandalone.frontendWinId != 0, 0);
-        carla_debug("CarlaNSM::handleShowHideGui(%s)", bool2str(show));
+        CARLA_SAFE_ASSERT_RETURN(fOscAddress != nullptr, 1);
+        CARLA_SAFE_ASSERT_RETURN(fOscServer != nullptr, 1);
+        carla_stdout("CarlaNSM::handleBroadcast(%s, %p, %i)", types, argv, argc);
 
-#ifndef BUILD_ANSI_TEST
-        lo_send_from(lo_message_get_source(msg), fOscServer, LO_TT_IMMEDIATE, show ? "/nsm/client/gui_is_shown" : "/nsm/client/gui_is_hidden", "");
-#endif
+        // TODO
 
         return 0;
     }
-#endif
 
 private:
-    lo_server fOscServer;
-
-    CarlaString fClientId;
-    CarlaString fProjectPath;
+    lo_address       fOscAddress;
+    lo_server        fOscServer;
+    lo_server_thread fOscServerThread;
+    CarlaString      fProjectPath;
 
     bool fHasBroadcast;
-    bool fHasShowHideUI;
+    bool fHasOptionalGui;
+    bool fHasServerControl;
+    bool fStarted;
 
     #define handlePtr ((CarlaNSM*)data)
 
-    static void _error_handler(int num, const char* msg, const char* path)
+    static void _osc_error_handler(int num, const char* msg, const char* path)
     {
-        carla_stderr2("CarlaNSM::_error_handler(%i, \"%s\", \"%s\")", num, msg, path);
+        carla_stderr2("CarlaNSM::_osc_error_handler(%i, \"%s\", \"%s\")", num, msg, path);
+    }
+
+    static int _error_handler(const char*, const char* types, lo_arg** argv, int argc, lo_message, void* data)
+    {
+        CARLA_SAFE_ASSERT_RETURN(argc == 3, 1);
+        CARLA_SAFE_ASSERT_RETURN(std::strcmp(types, "sis") == 0, 1);
+
+        const char* const method  = &argv[0]->s;
+        const int         code    =  argv[1]->i;
+        const char* const message = &argv[2]->s;
+
+        return handlePtr->handleError(method, code, message);
     }
 
-    static int _reply_handler(const char* path, const char* types, lo_arg** argv, int argc, lo_message msg, void* data)
+    static int _reply_handler(const char*, const char* types, lo_arg** argv, int argc, lo_message msg, void* data)
     {
-        return handlePtr->handleReply(path, types, argv, argc, msg);
+        CARLA_SAFE_ASSERT_RETURN(argc == 4, 1);
+        CARLA_SAFE_ASSERT_RETURN(std::strcmp(types, "ssss") == 0, 1);
+
+        const char* const method   = &argv[0]->s;
+        const char* const message  = &argv[1]->s;
+        const char* const smName   = &argv[2]->s;
+        const char* const features = &argv[3]->s;
+
+        return handlePtr->handleReply(method, message, smName, features, msg);
     }
 
-    static int _open_handler(const char* path, const char* types, lo_arg** argv, int argc, lo_message msg, void* data)
+    static int _open_handler(const char*, const char* types, lo_arg** argv, int argc, lo_message, void* data)
     {
-        return handlePtr->handleOpen(path, types, argv, argc, msg);
+        CARLA_SAFE_ASSERT_RETURN(argc == 3, 1);
+        CARLA_SAFE_ASSERT_RETURN(std::strcmp(types, "sss") == 0, 1);
+
+        const char* const projectPath  = &argv[0]->s;
+        const char* const displayName  = &argv[1]->s;
+        const char* const clientNameId = &argv[2]->s;
+
+        return handlePtr->handleOpen(projectPath, displayName, clientNameId);
     }
 
-    static int _save_handler(const char* path, const char* types, lo_arg** argv, int argc, lo_message msg, void* data)
+    static int _save_handler(const char*, const char*, lo_arg**, int argc, lo_message, void* data)
     {
-        return handlePtr->handleSave(path, types, argv, argc, msg);
+        CARLA_SAFE_ASSERT_RETURN(argc == 0, 1);
+
+        return handlePtr->handleSave();
     }
 
-#if 0
-    static int _show_gui_handler(const char*, const char*, lo_arg**, int, lo_message, void* data)
+    static int _loaded_handler(const char*, const char*, lo_arg**, int argc, lo_message, void* data)
     {
-        return handlePtr->handleShowHideGui(true);
+        CARLA_SAFE_ASSERT_RETURN(argc == 0, 1);
+
+        return handlePtr->handleSessionIsLoaded();
     }
 
-    static int _hide_gui_handler(const char*, const char*, lo_arg**, int, lo_message, void* data)
+    static int _show_gui_handler(const char*, const char*, lo_arg**, int argc, lo_message, void* data)
     {
-        return handlePtr->handleShowHideGui(false);
+        CARLA_SAFE_ASSERT_RETURN(argc == 0, 1);
+
+        return handlePtr->handleShowOptionalGui();
+    }
+
+    static int _hide_gui_handler(const char*, const char*, lo_arg**, int argc, lo_message, void* data)
+    {
+        CARLA_SAFE_ASSERT_RETURN(argc == 0, 1);
+
+        return handlePtr->handleHideOptionalGui();
+    }
+
+    static int _broadcast_handler(const char* path, const char* types, lo_arg** argv, int argc, lo_message, void* data)
+    {
+        return handlePtr->handleBroadcast(types, argv, argc);
     }
-#endif
 
     #undef handlePtr
 
@@ -347,8 +423,6 @@ private:
     CARLA_DECLARE_NON_COPY_CLASS(CarlaNSM)
 };
 
-static CarlaNSM gNSM;
-
 #endif // HAVE_LIBLO
 
 // -------------------------------------------------------------------------------------------------------------------
@@ -685,9 +759,6 @@ void carla_engine_idle()
 {
     CARLA_SAFE_ASSERT_RETURN(gStandalone.engine != nullptr,);
 
-#ifdef HAVE_LIBLO
-    gNSM.idle();
-#endif
     gStandalone.engine->idle();
 }
 
@@ -793,14 +864,6 @@ void carla_set_engine_option(EngineOption option, int value, const char* valueSt
         gStandalone.engineOptions.audioDevice = carla_strdup_safe(valueStr);
         break;
 
-    case CB:: ENGINE_OPTION_NSM_INIT:
-        CARLA_SAFE_ASSERT_RETURN(value != 0,);
-        CARLA_SAFE_ASSERT_RETURN(valueStr != nullptr && valueStr[0] != '\0',);
-#ifdef HAVE_LIBLO
-        gNSM.announce(value, valueStr);
-#endif
-        break;
-
     case CB::ENGINE_OPTION_PLUGIN_PATH:
         CARLA_SAFE_ASSERT_RETURN(value > CB::PLUGIN_NONE,);
         CARLA_SAFE_ASSERT_RETURN(value <= CB::PLUGIN_SFZ,);
@@ -2195,6 +2258,27 @@ const char* carla_get_host_osc_url_udp()
 
 // -------------------------------------------------------------------------------------------------------------------
 
+bool carla_nsm_init(int pid, const char* executableName)
+{
+#ifdef HAVE_LIBLO
+    return CarlaNSM::getInstance().announce(pid, executableName);
+#else
+    return false;
+
+    // unused
+    (void)pid; (void)executableName;
+#endif
+}
+
+void carla_nsm_ready()
+{
+#ifdef HAVE_LIBLO
+    CarlaNSM::getInstance().start();
+#endif
+}
+
+// -------------------------------------------------------------------------------------------------------------------
+
 #include "CarlaPluginUI.cpp"
 #include "CarlaDssiUtils.cpp"
 #include "CarlaPatchbayUtils.cpp"

source/backend/engine/CarlaEngine.cpp

@@ -1214,7 +1214,6 @@ void CarlaEngine::setOption(const EngineOption option, const int value, const ch
     switch (option)
     {
     case ENGINE_OPTION_DEBUG:
-    case ENGINE_OPTION_NSM_INIT:
         break;
 
     case ENGINE_OPTION_PROCESS_MODE:

source/carla_backend.py

@@ -671,21 +671,25 @@ ENGINE_CALLBACK_BUFFER_SIZE_CHANGED = 33
 # @a value3 New sample rate
 ENGINE_CALLBACK_SAMPLE_RATE_CHANGED = 34
 
+# NSM callback.
+# (Work in progress, values are not defined yet)
+ENGINE_CALLBACK_NSM = 35
+
 # Idle frontend.
 # This is used by the engine during long operations that might block the frontend,
 # giving it the possibility to idle while the operation is still in place.
-ENGINE_CALLBACK_IDLE = 35
+ENGINE_CALLBACK_IDLE = 36
 
 # Show a message as information.
 # @a valueStr The message
-ENGINE_CALLBACK_INFO = 36
+ENGINE_CALLBACK_INFO = 37
 
 # Show a message as an error.
 # @a valueStr The message
-ENGINE_CALLBACK_ERROR = 37
+ENGINE_CALLBACK_ERROR = 38
 
 # The engine has crashed or malfunctioned and will no longer work.
-ENGINE_CALLBACK_QUIT = 38
+ENGINE_CALLBACK_QUIT = 39
 
 # ------------------------------------------------------------------------------------------------------------
 # Engine Option
@@ -748,30 +752,27 @@ ENGINE_OPTION_AUDIO_SAMPLE_RATE = 11
 # Default unset.
 ENGINE_OPTION_AUDIO_DEVICE = 12
 
-# Set data needed for NSM support.
-ENGINE_OPTION_NSM_INIT = 13
-
 # Set path used for a specific plugin type.
 # Uses value as the plugin format, valueStr as actual path.
 # @see PluginType
-ENGINE_OPTION_PLUGIN_PATH = 14
+ENGINE_OPTION_PLUGIN_PATH = 13
 
 # Set path to the binary files.
 # Default unset.
 # @note Must be set for plugin and UI bridges to work
-ENGINE_OPTION_PATH_BINARIES = 15
+ENGINE_OPTION_PATH_BINARIES = 14
 
 # Set path to the resource files.
 # Default unset.
 # @note Must be set for some internal plugins to work
-ENGINE_OPTION_PATH_RESOURCES = 16
+ENGINE_OPTION_PATH_RESOURCES = 15
 
 # Prevent bad plugin and UI behaviour.
 # @note: Linux only
-ENGINE_OPTION_PREVENT_BAD_BEHAVIOUR = 17
+ENGINE_OPTION_PREVENT_BAD_BEHAVIOUR = 16
 
 # Set frontend winId, used to define as parent window for plugin UIs.
-ENGINE_OPTION_FRONTEND_WIN_ID = 18
+ENGINE_OPTION_FRONTEND_WIN_ID = 17
 
 # ------------------------------------------------------------------------------------------------------------
 # Engine Process Mode
@@ -1194,6 +1195,7 @@ class CarlaHostMeta(object):
         # info about this host object
         self.isControl = False
         self.isPlugin  = False
+        self.nsmOK     = False
 
         # settings
         self.processMode       = ENGINE_PROCESS_MODE_CONTINUOUS_RACK
@@ -2343,6 +2345,12 @@ class CarlaHostDLL(CarlaHostMeta):
         self.lib.carla_get_host_osc_url_udp.argtypes = None
         self.lib.carla_get_host_osc_url_udp.restype = c_char_p
 
+        self.lib.carla_nsm_init.argtypes = [c_int, c_char_p]
+        self.lib.carla_nsm_init.restype = c_bool
+
+        self.lib.carla_nsm_ready.argtypes = None
+        self.lib.carla_nsm_ready.restype = None
+
     # --------------------------------------------------------------------------------------------------------
 
     def get_engine_driver_count(self):
@@ -2605,6 +2613,12 @@ class CarlaHostDLL(CarlaHostMeta):
     def get_host_osc_url_udp(self):
         return charPtrToString(self.lib.carla_get_host_osc_url_udp())
 
+    def nsm_init(self, pid, executableName):
+        return bool(self.lib.carla_nsm_init(pid, executableName.encode("utf-8")))
+
+    def nsm_ready(self):
+        self.lib.carla_nsm_ready()
+
 # ------------------------------------------------------------------------------------------------------------
 # Helper object for CarlaHostPlugin
 

source/carla_backend_qt.py

@@ -80,6 +80,7 @@ class CarlaHostSignals(QObject):
     TransportModeChangedCallback = pyqtSignal(int)
     BufferSizeChangedCallback = pyqtSignal(int)
     SampleRateChangedCallback = pyqtSignal(float)
+    NSMCallback = pyqtSignal(int, int, str)
     InfoCallback = pyqtSignal(str)
     ErrorCallback = pyqtSignal(str)
     QuitCallback = pyqtSignal()

source/carla_host.py

@@ -121,9 +121,9 @@ class HostWindow(QMainWindow):
         elif LADISH_APP_NAME:
             self.fClientName         = LADISH_APP_NAME
             self.fSessionManagerName = "LADISH"
-        elif NSM_URL:
-            self.fClientName         = "Carla" # "Carla.tmp"
-            self.fSessionManagerName = "Non Session Manager"
+        elif NSM_URL and host.nsmOK:
+            self.fClientName         = "Carla.tmp"
+            self.fSessionManagerName = "Non Session Manager TMP"
         else:
             self.fClientName         = CARLA_CLIENT_NAME or "Carla"
             self.fSessionManagerName = ""
@@ -387,6 +387,8 @@ class HostWindow(QMainWindow):
         host.PatchbayConnectionAddedCallback.connect(self.slot_handlePatchbayConnectionAddedCallback)
         host.PatchbayConnectionRemovedCallback.connect(self.slot_handlePatchbayConnectionRemovedCallback)
 
+        host.NSMCallback.connect(self.slot_handleNSMCallback)
+
         host.DebugCallback.connect(self.slot_handleDebugCallback)
         host.InfoCallback.connect(self.slot_handleInfoCallback)
         host.ErrorCallback.connect(self.slot_handleErrorCallback)
@@ -407,6 +409,13 @@ class HostWindow(QMainWindow):
         if self.host.isPlugin:
             self.startTimers()
 
+        # For NSM we wait for the open message
+        if NSM_URL and host.nsmOK:
+            self.fFirstEngineInit = False
+            self.setEngineSettings()
+            host.nsm_ready()
+            return
+
         QTimer.singleShot(0, self.slot_engineStart)
 
     # --------------------------------------------------------------------------------------------------------
@@ -429,7 +438,7 @@ class HostWindow(QMainWindow):
     def setProperWindowTitle(self):
         title = self.fClientName
 
-        if self.fProjectFilename:
+        if self.fProjectFilename and not self.host.nsmOK:
             title += " - %s" % os.path.basename(self.fProjectFilename)
         if self.fSessionManagerName:
             title += " (%s)" % self.fSessionManagerName
@@ -605,9 +614,11 @@ class HostWindow(QMainWindow):
             self.ui.act_engine_start.setEnabled(False)
             self.ui.act_engine_stop.setEnabled(True)
 
+            canSave = (self.fProjectFilename and os.path.exists(self.fProjectFilename)) or not self.fSessionManagerName
+            self.ui.act_file_save.setEnabled(canSave)
+
             if not self.fSessionManagerName:
                 self.ui.act_file_open.setEnabled(True)
-                self.ui.act_file_save.setEnabled(True)
                 self.ui.act_file_save_as.setEnabled(True)
 
             self.ui.panelTime.setEnabled(True)
@@ -1564,6 +1575,45 @@ class HostWindow(QMainWindow):
 
     # --------------------------------------------------------------------------------------------------------
 
+    @pyqtSlot(int, int, str)
+    def slot_handleNSMCallback(self, value1, value2, valueStr):
+        print("--------------- NSM:", value1, value2, valueStr)
+
+        # Error
+        if value1 == 0:
+            pass
+
+        # Reply
+        elif value1 == 1:
+            self.fFirstEngineInit    = False
+            self.fSessionManagerName = valueStr
+            self.setProperWindowTitle()
+
+        # Open
+        elif value1 == 2:
+            self.fClientName      = os.path.basename(valueStr)
+            self.fProjectFilename = QFileInfo(valueStr+".carxp").absoluteFilePath()
+            self.setProperWindowTitle()
+            self.ui.act_file_save.setEnabled(True)
+
+        # Save
+        elif value1 == 3:
+            pass
+
+        # Session is Loaded
+        elif value1 == 4:
+            pass
+
+        # Show Optional Gui
+        elif value1 == 5:
+            self.show()
+
+        # Hide Optional Gui
+        elif value1 == 6:
+            self.hide()
+
+    # --------------------------------------------------------------------------------------------------------
+
     @pyqtSlot(int, int, int, float, str)
     def slot_handleDebugCallback(self, pluginId, value1, value2, value3, valueStr):
         print("DEBUG:", pluginId, value1, value2, value3, valueStr)
@@ -1951,6 +2001,8 @@ def engineCallback(host, action, pluginId, value1, value2, value3, valueStr):
         host.BufferSizeChangedCallback.emit(value1)
     elif action == ENGINE_CALLBACK_SAMPLE_RATE_CHANGED:
         host.SampleRateChangedCallback.emit(value3)
+    elif action == ENGINE_CALLBACK_NSM:
+        host.NSMCallback.emit(value1, value2, valueStr)
     elif action == ENGINE_CALLBACK_IDLE:
         QApplication.instance().processEvents()
     elif action == ENGINE_CALLBACK_INFO:
@@ -2048,7 +2100,7 @@ def initHost(initName, libPrefixOrPluginClass, isControl, isPlugin, failError):
         host.set_engine_option(ENGINE_OPTION_PATH_RESOURCES, 0, pathResources)
 
         if not isControl:
-            host.set_engine_option(ENGINE_OPTION_NSM_INIT, os.getpid(), initName)
+            host.nsmOK = host.nsm_init(os.getpid(), initName)
 
     # --------------------------------------------------------------------------------------------------------
     # Init utils

source/utils/CarlaBackendUtils.hpp

@@ -270,6 +270,8 @@ const char* EngineCallbackOpcode2Str(const EngineCallbackOpcode opcode) noexcept
         return "ENGINE_CALLBACK_BUFFER_SIZE_CHANGED";
     case ENGINE_CALLBACK_SAMPLE_RATE_CHANGED:
         return "ENGINE_CALLBACK_SAMPLE_RATE_CHANGED";
+    case ENGINE_CALLBACK_NSM:
+        return "ENGINE_CALLBACK_NSM";
     case ENGINE_CALLBACK_IDLE:
         return "ENGINE_CALLBACK_IDLE";
     case ENGINE_CALLBACK_INFO:
@@ -315,8 +317,6 @@ const char* EngineOption2Str(const EngineOption option) noexcept
         return "ENGINE_OPTION_AUDIO_SAMPLE_RATE";
     case ENGINE_OPTION_AUDIO_DEVICE:
         return "ENGINE_OPTION_AUDIO_DEVICE";
-    case ENGINE_OPTION_NSM_INIT:
-        return "ENGINE_OPTION_NSM_INIT";
     case ENGINE_OPTION_PLUGIN_PATH:
         return "ENGINE_OPTION_PLUGIN_PATH";
     case ENGINE_OPTION_PATH_BINARIES: