Move static host stuff to engine, so it works for carla-plugin

source/backend/CarlaBackend.h

@@ -1021,7 +1021,12 @@ typedef enum {
      * Default unset.
      * @note Must be set for some internal plugins to work
      */
-    ENGINE_OPTION_PATH_RESOURCES = 14
+    ENGINE_OPTION_PATH_RESOURCES = 14,
+
+    /*!
+     * Set frontend winId, used to define as parent window for plugin UIs.
+     */
+    ENGINE_OPTION_FRONTEND_WIN_ID = 15
 
 } EngineOption;
 
@@ -1094,6 +1099,33 @@ typedef enum {
 
 } EngineTransportMode;
 
+/* ------------------------------------------------------------------------------------------------------------
+ * File Callback Opcode */
+
+/*!
+ * File callback opcodes.\n
+ * Front-ends must always block-wait for user input.
+ * @see FileCallbackFunc, CarlaEngine::setFileCallback() and carla_set_file_callback()
+ */
+typedef enum {
+    /*!
+     * Debug.\n
+     * This opcode is undefined and used only for testing purposes.
+     */
+    FILE_CALLBACK_DEBUG = 0,
+
+    /*!
+     * Open file or folder.
+     */
+    FILE_CALLBACK_OPEN = 1,
+
+    /*!
+     * Save file or folder.
+     */
+    FILE_CALLBACK_SAVE = 2
+
+} FileCallbackOpcode;
+
 /* ------------------------------------------------------------------------------------------------------------
  * Patchbay Icon */
 
@@ -1148,6 +1180,12 @@ enum PatchbayIcon {
  */
 typedef void (*EngineCallbackFunc)(void* ptr, EngineCallbackOpcode action, uint pluginId, int value1, int value2, float value3, const char* valueStr);
 
+/*!
+ * File callback function.
+ * @see FileCallbackOpcode
+ */
+typedef const char* (*FileCallbackFunc)(void* ptr, FileCallbackOpcode action, bool isDir, const char* title, const char* filter);
+
 /*!
  * Parameter data.
  */

source/backend/CarlaEngine.hpp

@@ -242,6 +242,8 @@ struct EngineOptions {
     const char* binaryDir;
     const char* resourceDir;
 
+    uintptr_t frontendWinId;
+
 #ifndef DOXYGEN
     EngineOptions() noexcept;
     ~EngineOptions();
@@ -874,15 +876,30 @@ public:
     // Callback
 
     /*!
-     * TODO.
+     * Run the main engine callback, if set.
+     * May be called by plugins.
      */
     void callback(const EngineCallbackOpcode action, const unsigned int pluginId, const int value1, const int value2, const float value3, const char* const valueStr) noexcept;
 
     /*!
-     * TODO.
+     * Set the main engine callback.
      */
     void setCallback(const EngineCallbackFunc func, void* const ptr) noexcept;
 
+    // -------------------------------------------------------------------
+    // Callback
+
+    /*!
+     * Run the file callback, if set.
+     * May be called by plugins.
+     */
+    const char* runFileCallback(const FileCallbackOpcode action, const bool isDir, const char* const title, const char* const filter) noexcept;
+
+    /*!
+     * Set the file callback.
+     */
+    void setFileCallback(const FileCallbackFunc func, void* const ptr) noexcept;
+
 #ifndef BUILD_BRIDGE
     // -------------------------------------------------------------------
     // Patchbay

source/backend/CarlaHost.h

@@ -29,7 +29,9 @@ using CarlaBackend::EngineCallbackOpcode;
 using CarlaBackend::EngineOption;
 using CarlaBackend::EngineProcessMode;
 using CarlaBackend::EngineTransportMode;
+using CarlaBackend::FileCallbackOpcode;
 using CarlaBackend::EngineCallbackFunc;
+using CarlaBackend::FileCallbackFunc;
 using CarlaBackend::ParameterData;
 using CarlaBackend::ParameterRanges;
 using CarlaBackend::MidiProgramData;
@@ -51,42 +53,9 @@ using CarlaBackend::CarlaPlugin;
  * @{
  */
 
-/* ------------------------------------------------------------------------------------------------------------
- * File Callback Opcode */
-
-/*!
- * File callback opcodes.\n
- * Front-ends must always block-wait for user input.
- * @see FileCallbackFunc and carla_set_file_callback()
- */
-typedef enum {
-    /*!
-     * Debug.\n
-     * This opcode is undefined and used only for testing purposes.
-     */
-    FILE_CALLBACK_DEBUG = 0,
-
-    /*!
-     * Open file or folder.
-     */
-    FILE_CALLBACK_OPEN = 1,
-
-    /*!
-     * Save file or folder.
-     */
-    FILE_CALLBACK_SAVE = 2
-
-} FileCallbackOpcode;
-
 /* ------------------------------------------------------------------------------------------------------------
  * Carla Host API (C stuff) */
 
-/*!
- * File callback function.
- * @see FileCallbackOpcode
- */
-typedef const char* (*FileCallbackFunc)(void* ptr, FileCallbackOpcode action, bool isDir, const char* title, const char* filter);
-
 /*!
  * Information about a loaded plugin.
  * @see carla_get_plugin_info()
@@ -1069,10 +1038,4 @@ CARLA_EXPORT const char* carla_get_host_osc_url_udp();
 
 /** @} */
 
-/*!
- * Implemented in standalone.
- */
-extern ulong carla_standalone_get_transient_win_id();
-extern const char* carla_standalone_file_callback(FileCallbackOpcode action, bool isDir, const char* title, const char* filter);
-
 #endif /* CARLA_HOST_H_INCLUDED */

source/backend/engine/CarlaEngine.cpp

@@ -1604,6 +1604,33 @@ void CarlaEngine::setCallback(const EngineCallbackFunc func, void* const ptr) no
     pData->callbackPtr = ptr;
 }
 
+// -----------------------------------------------------------------------
+// File Callback
+
+const char* CarlaEngine::runFileCallback(const FileCallbackOpcode action, const bool isDir, const char* const title, const char* const filter) noexcept
+{
+    CARLA_SAFE_ASSERT_RETURN(title != nullptr && title[0] != '\0', nullptr);
+    CARLA_SAFE_ASSERT_RETURN(filter != nullptr && filter[0] != '\0', nullptr);
+    carla_debug("CarlaEngine::runFileCallback(%i:%s, %s, \"%s\", \"%s\")", action, FileCallbackOpcode2Str(action), bool2str(isDir), title, filter);
+
+    const char* ret = nullptr;
+
+    if (pData->fileCallback != nullptr)
+    {
+        try {
+            ret = pData->fileCallback(pData->fileCallbackPtr, action, isDir, title, filter);
+        } catch(...) {}
+    }
+
+    return ret;
+}
+
+void CarlaEngine::setFileCallback(const FileCallbackFunc func, void* const ptr) noexcept
+{
+    pData->fileCallback    = func;
+    pData->fileCallbackPtr = ptr;
+}
+
 #ifndef BUILD_BRIDGE
 // -----------------------------------------------------------------------
 // Patchbay
@@ -1937,6 +1964,13 @@ void CarlaEngine::setOption(const EngineOption option, const int value, const ch
 
         pData->options.resourceDir = carla_strdup(valueStr);
         break;
+
+    case ENGINE_OPTION_FRONTEND_WIN_ID:
+        CARLA_SAFE_ASSERT_RETURN(valueStr != nullptr && valueStr[0] != '\0',);
+        const long winId(std::atol(valueStr));
+        CARLA_SAFE_ASSERT_RETURN(winId >= 0,);
+        pData->options.frontendWinId = static_cast<uintptr_t>(winId);
+        break;
     }
 }
 

source/backend/engine/CarlaEngineInternal.cpp

@@ -211,7 +211,8 @@ EngineOptions::EngineOptions() noexcept
       audioSampleRate(44100),
       audioDevice(nullptr),
       binaryDir(nullptr),
-      resourceDir(nullptr) {}
+      resourceDir(nullptr),
+      frontendWinId(0) {}
 
 EngineOptions::~EngineOptions()
 {
@@ -597,6 +598,8 @@ CarlaEngineProtectedData::CarlaEngineProtectedData(CarlaEngine* const engine)
       oscData(nullptr),
       callback(nullptr),
       callbackPtr(nullptr),
+      fileCallback(nullptr),
+      fileCallbackPtr(nullptr),
       hints(0x0),
       bufferSize(0),
       sampleRate(0.0),

source/backend/engine/CarlaEngineInternal.hpp

@@ -211,6 +211,9 @@ struct CarlaEngineProtectedData {
     EngineCallbackFunc callback;
     void*              callbackPtr;
 
+    FileCallbackFunc fileCallback;
+    void*            fileCallbackPtr;
+
     unsigned int hints;
     uint32_t     bufferSize;
     double       sampleRate;

source/backend/plugin/CarlaPlugin.cpp

@@ -67,7 +67,7 @@ struct ParamSymbol {
 
 void CarlaPluginProtectedData::tryTransient()
 {
-    if (carla_standalone_get_transient_win_id() != 0)
+    if (engine->getOptions().frontendWinId != 0)
         transientTryCounter = 1;
 }
 
@@ -1381,7 +1381,7 @@ void CarlaPlugin::idle()
     carla_stdout("Trying to get window...");
 
     QString uiTitle(QString("%1 (GUI)").arg(pData->name));
-    if (CarlaPluginUi::tryTransientWinIdMatch(pData->osc.data.target != nullptr ? pData->osc.thread.getPid() : 0, uiTitle.toUtf8().constData(), carla_standalone_get_transient_win_id()))
+    if (CarlaPluginUi::tryTransientWinIdMatch(pData->osc.data.target != nullptr ? pData->osc.thread.getPid() : 0, uiTitle.toUtf8().constData(), pData->engine->getOptions().frontendWinId))
         pData->transientTryCounter = 0;
 }
 
@@ -1672,7 +1672,7 @@ void CarlaPlugin::updateOscData(const lo_address& source, const char* const url)
     for (uint32_t i=0; i < pData->param.count; ++i)
         osc_send_control(pData->osc.data, pData->param.data[i].rindex, getParameterValue(i));
 
-    if ((pData->hints & PLUGIN_HAS_CUSTOM_UI) != 0 && carla_standalone_get_transient_win_id() != 0)
+    if ((pData->hints & PLUGIN_HAS_CUSTOM_UI) != 0 && pData->engine->getOptions().frontendWinId != 0)
         pData->transientTryCounter = 1;
 
     carla_stdout("CarlaPlugin::updateOscData() - done");

source/backend/plugin/CarlaPluginUi.cpp

@@ -31,12 +31,12 @@
 class X11PluginUi : public CarlaPluginUi
 {
 public:
-    X11PluginUi(CloseCallback* cb) noexcept
-        : CarlaPluginUi(cb),
+    X11PluginUi(CloseCallback* const cb, const uintptr_t parentId) noexcept
+        : CarlaPluginUi(cb, parentId),
           fDisplay(nullptr),
           fWindow(0)
      {
-        fDisplay = XOpenDisplay(0);
+        fDisplay = XOpenDisplay(nullptr);
         CARLA_SAFE_ASSERT_RETURN(fDisplay != nullptr,);
 
         const int screen = DefaultScreen(fDisplay);
@@ -56,8 +56,8 @@ public:
         Atom wmDelete = XInternAtom(fDisplay, "WM_DELETE_WINDOW", True);
         XSetWMProtocols(fDisplay, fWindow, &wmDelete, 1);
 
-        if (const uintptr_t transientId = carla_standalone_get_transient_win_id())
-            setTransientWinId(transientId);
+        if (parentId != 0)
+            setTransientWinId(parentId);
     }
 
     ~X11PluginUi() override
@@ -292,27 +292,27 @@ bool CarlaPluginUi::tryTransientWinIdMatch(const ulong pid, const char* const ui
 // -----------------------------------------------------
 
 #ifdef CARLA_OS_MAC
-CarlaPluginUi* CarlaPluginUi::newCocoa(CloseCallback* cb)
+CarlaPluginUi* CarlaPluginUi::newCocoa(CloseCallback* cb, uintptr_t)
 {
-    //return new CocoaPluginUi(cb);
+    //return new CocoaPluginUi(cb, parentId);
     return nullptr;
     (void)cb;
 }
 #endif
 
 #ifdef CARLA_OS_WIN
-CarlaPluginUi* CarlaPluginUi::newWindows(CloseCallback* cb)
+CarlaPluginUi* CarlaPluginUi::newWindows(CloseCallback* cb, uintptr_t)
 {
-    //return new WindowsPluginUi(cb);
+    //return new WindowsPluginUi(cb, parentId);
     return nullptr;
     (void)cb;
 }
 #endif
 
 #ifdef HAVE_X11
-CarlaPluginUi* CarlaPluginUi::newX11(CloseCallback* cb)
+CarlaPluginUi* CarlaPluginUi::newX11(CloseCallback* cb, uintptr_t parentId)
 {
-    return new X11PluginUi(cb);
+    return new X11PluginUi(cb, parentId);
 }
 #endif
 

source/backend/plugin/CarlaPluginUi.hpp

@@ -44,18 +44,18 @@ public:
     static bool tryTransientWinIdMatch(const ulong pid, const char* const uiTitle, const uintptr_t winId);
 
 #ifdef CARLA_OS_MAC
-    static CarlaPluginUi* newCocoa(CloseCallback*);
+    static CarlaPluginUi* newCocoa(CloseCallback*, uintptr_t);
 #endif
 #ifdef CARLA_OS_WIN
-    static CarlaPluginUi* newWindows(CloseCallback*);
+    static CarlaPluginUi* newWindows(CloseCallback*, uintptr_t);
 #endif
 #ifdef HAVE_X11
-    static CarlaPluginUi* newX11(CloseCallback*);
+    static CarlaPluginUi* newX11(CloseCallback*, uintptr_t);
 #endif
 
 protected:
     CloseCallback* fCallback;
-    CarlaPluginUi(CloseCallback* cb) noexcept : fCallback(cb) {}
+    CarlaPluginUi(CloseCallback* const cb, const uintptr_t) noexcept : fCallback(cb) {}
 };
 
 // -----------------------------------------------------

source/backend/plugin/Lv2Plugin.cpp

@@ -1129,6 +1129,7 @@ public:
                 if (fUi.type == UI::TYPE_EMBED)
                 {
                     const char* msg = nullptr;
+                    const uintptr_t frontendWinId(pData->engine->getOptions().frontendWinId);
 
                     switch (fUi.rdfDescriptor->Type)
                     {
@@ -1143,7 +1144,7 @@ public:
 
                     case LV2_UI_COCOA:
 # ifdef CARLA_OS_MAC
-                        fUi.window = CarlaPluginUi::newCocoa(this);
+                        fUi.window = CarlaPluginUi::newCocoa(this, frontendWinId);
 # else
                         msg = "UI is for MacOS only";
 # endif
@@ -1151,7 +1152,7 @@ public:
 
                     case LV2_UI_WINDOWS:
 # ifdef CARLA_OS_WIN
-                        fUi.window = CarlaPluginUi::newWindows(this);
+                        fUi.window = CarlaPluginUi::newWindows(this, frontendWinId);
 # else
                         msg = "UI is for Windows only";
 # endif
@@ -1159,7 +1160,7 @@ public:
 
                     case LV2_UI_X11:
 # ifdef HAVE_X11
-                        fUi.window = CarlaPluginUi::newX11(this);
+                        fUi.window = CarlaPluginUi::newX11(this, frontendWinId);
 # else
                         msg = "UI is only for systems with X11";
 # endif

source/backend/plugin/Makefile

@@ -67,7 +67,7 @@ CarlaPluginThread.cpp.o: CarlaPluginThread.cpp $(CARLA_PLUGIN_HPP) $(CARLA_PLUGI
 CarlaPluginUi.cpp.o: CarlaPluginUi.cpp $(CARLA_PLUGIN_UI_HPP) $(CARLA_HOST_H)
 	$(CXX) $< $(BUILD_CXX_FLAGS) -c -o $@
 
-NativePlugin.cpp.o: NativePlugin.cpp $(CARLA_PLUGIN_INTERNAL_HPP) $(CARLA_ENGINE_HPP) $(CARLA_MATH_UTILS_HPP) $(CARLA_NATIVE_H) $(CARLA_HOST_H)
+NativePlugin.cpp.o: NativePlugin.cpp $(CARLA_PLUGIN_INTERNAL_HPP) $(CARLA_ENGINE_HPP) $(CARLA_MATH_UTILS_HPP) $(CARLA_NATIVE_H)
 	$(CXX) $< $(BUILD_CXX_FLAGS) $(QTCORE_FLAGS) -c -o $@
 
 BridgePlugin.cpp.o: BridgePlugin.cpp $(CARLA_PLUGIN_INTERNAL_HPP) $(CARLA_ENGINE_HPP) $(CARLA_BACKEND_UTILS_HPP) $(CARLA_BRIDGE_UTILS_HPP) $(CARLA_MATH_UTILS_HPP) $(CARLA_SHM_UTILS_HPP) $(JACK_BRIDGE_HPP)

source/backend/plugin/NativePlugin.cpp

@@ -23,7 +23,6 @@
 #include "CarlaMathUtils.hpp"
 
 #include "CarlaNative.h"
-#include "CarlaHost.h"
 
 #include <QtCore/QStringList>
 
@@ -2082,12 +2081,12 @@ protected:
 
     const char* handleUiOpenFile(const bool isDir, const char* const title, const char* const filter)
     {
-        return carla_standalone_file_callback(FILE_CALLBACK_OPEN, isDir, title, filter);
+        return pData->engine->runFileCallback(FILE_CALLBACK_OPEN, isDir, title, filter);
     }
 
     const char* handleUiSaveFile(const bool isDir, const char* const title, const char* const filter)
     {
-        return carla_standalone_file_callback(FILE_CALLBACK_SAVE, isDir, title, filter);
+        return pData->engine->runFileCallback(FILE_CALLBACK_SAVE, isDir, title, filter);
     }
 
     intptr_t handleDispatcher(const NativeHostDispatcherOpcode opcode, const int32_t index, const intptr_t value, void* const ptr, const float opt)

source/backend/plugin/VstPlugin.cpp

@@ -414,21 +414,22 @@ public:
             if (fUi.window == nullptr)
             {
                 const char* msg = nullptr;
+                const uintptr_t frontendWinId(pData->engine->getOptions().frontendWinId);
 
 #if defined(CARLA_OS_LINUX)
 # ifdef HAVE_X11
-                fUi.window = CarlaPluginUi::newX11(this);
+                fUi.window = CarlaPluginUi::newX11(this, frontendWinId);
 # else
                 msg = "UI is only for systems with X11";
 # endif
 #elif defined(CARLA_OS_MAC)
 # ifdef __LP64__
-                fUi.window = CarlaPluginUi::newCocoa(this);
+                fUi.window = CarlaPluginUi::newCocoa(this, frontendWinId);
 # else
-                fUi.window = CarlaPluginUi::newCarbon(this);
+                fUi.window = CarlaPluginUi::newCarbon(this, frontendWinId);
 # endif
 #elif defined(CARLA_OS_WIN)
-                fUi.window = CarlaPluginUi::newWindows(this);
+                fUi.window = CarlaPluginUi::newWindows(this, frontendWinId);
 #else
                 msg = "Unknown UI type";
 #endif

source/backend/standalone/CarlaStandalone.cpp

@@ -117,15 +117,6 @@ struct CarlaBackendStandalone {
 
 static CarlaBackendStandalone gStandalone;
 
-// -------------------------------------------------------------------------------------------------------------------
-
-static ulong gTransientWinId = 0;
-
-ulong carla_standalone_get_transient_win_id()
-{
-    return gTransientWinId;
-}
-
 // -------------------------------------------------------------------------------------------------------------------
 // API
 
@@ -406,6 +397,7 @@ bool carla_engine_init(const char* driverName, const char* clientName)
     }
 
     gStandalone.engine->setCallback(gStandalone.engineCallback, gStandalone.engineCallbackPtr);
+    gStandalone.engine->setFileCallback(gStandalone.fileCallback, gStandalone.fileCallbackPtr);
 
 #ifdef BUILD_BRIDGE
     gStandalone.engine->setOption(CB::ENGINE_OPTION_PROCESS_MODE,          CB::ENGINE_PROCESS_MODE_MULTIPLE_CLIENTS,                     nullptr);
@@ -434,6 +426,15 @@ bool carla_engine_init(const char* driverName, const char* clientName)
     if (gStandalone.engineOptions.resourceDir != nullptr)
         gStandalone.engine->setOption(CB::ENGINE_OPTION_PATH_RESOURCES, 0, gStandalone.engineOptions.resourceDir);
 
+    if (gStandalone.engineOptions.frontendWinId != 0)
+    {
+        char strBuf[STR_MAX+1];
+        std::sprintf(strBuf, P_INTPTR, gStandalone.engineOptions.frontendWinId);
+        gStandalone.engine->setOption(CB::ENGINE_OPTION_FRONTEND_WIN_ID, 0, strBuf);
+    }
+    else
+        gStandalone.engine->setOption(CB::ENGINE_OPTION_FRONTEND_WIN_ID, 0, "0");
+
     if (gStandalone.engine->init(clientName))
     {
         gStandalone.lastError = "No error";
@@ -476,6 +477,7 @@ bool carla_engine_init_bridge(const char audioBaseName[6+1], const char controlB
     }
 
     gStandalone.engine->setCallback(gStandalone.engineCallback, gStandalone.engineCallbackPtr);
+    gStandalone.engine->setFileCallback(gStandalone.fileCallback, gStandalone.fileCallbackPtr);
 
     // forced options for bridge mode
     gStandalone.engine->setOption(CB::ENGINE_OPTION_PROCESS_MODE,          CB::ENGINE_PROCESS_MODE_BRIDGE,   nullptr);
@@ -490,6 +492,7 @@ bool carla_engine_init_bridge(const char audioBaseName[6+1], const char controlB
     gStandalone.engine->setOption(CB::ENGINE_OPTION_UI_BRIDGES_TIMEOUT,          static_cast<int>(gStandalone.engineOptions.uiBridgesTimeout), nullptr);
     gStandalone.engine->setOption(CB::ENGINE_OPTION_PATH_BINARIES,            0, (const char*)gStandalone.engineOptions.binaryDir);
     gStandalone.engine->setOption(CB::ENGINE_OPTION_PATH_RESOURCES,           0, (const char*)gStandalone.engineOptions.resourceDir);
+    // frontend winId here
 
     if (gStandalone.engine->init(clientName))
     {
@@ -584,13 +587,6 @@ void carla_set_engine_option(EngineOption option, int value, const char* valueSt
     switch (option)
     {
     case CB::ENGINE_OPTION_DEBUG:
-        if (value == -1729)
-        {
-            CARLA_SAFE_ASSERT_BREAK(valueStr != nullptr && valueStr[0] != '\0');
-            const long winId(std::atol(valueStr));
-            CARLA_SAFE_ASSERT_BREAK(winId != 0);
-            gTransientWinId = static_cast<ulong>(winId);
-        }
         break;
 
     case CB::ENGINE_OPTION_PROCESS_MODE:
@@ -674,6 +670,13 @@ void carla_set_engine_option(EngineOption option, int value, const char* valueSt
 
         gStandalone.engineOptions.resourceDir = carla_strdup(valueStr);
         break;
+
+    case CB::ENGINE_OPTION_FRONTEND_WIN_ID:
+        CARLA_SAFE_ASSERT_RETURN(valueStr != nullptr && valueStr[0] != '\0',);
+        const long winId(std::atol(valueStr));
+        CARLA_SAFE_ASSERT_RETURN(winId >= 0,);
+        gStandalone.engineOptions.frontendWinId = static_cast<uintptr_t>(winId);
+        break;
     }
 
     if (gStandalone.engine != nullptr)
@@ -681,26 +684,15 @@ void carla_set_engine_option(EngineOption option, int value, const char* valueSt
 }
 #endif
 
-// -------------------------------------------------------------------------------------------------------------------
-
 void carla_set_file_callback(FileCallbackFunc func, void* ptr)
 {
     carla_debug("carla_set_file_callback(%p, %p)", func, ptr);
 
     gStandalone.fileCallback    = func;
     gStandalone.fileCallbackPtr = ptr;
-}
 
-const char* carla_standalone_file_callback(FileCallbackOpcode action, bool isDir, const char* title, const char* filter)
-{
-    CARLA_SAFE_ASSERT_RETURN(title != nullptr && title[0] != '\0', nullptr);
-    CARLA_SAFE_ASSERT_RETURN(filter != nullptr && filter[0] != '\0', nullptr);
-    carla_debug("carla_standalone_file_callback(%i:%s, %s, \"%s\", \"%s\")", action, CB::FileCallbackOpcode2Str(action), bool2str(isDir), title, filter);
-
-    if (gStandalone.fileCallback == nullptr)
-        return nullptr;
-
-    return gStandalone.fileCallback(gStandalone.fileCallbackPtr, action, isDir, title, filter);
+    if (gStandalone.engine != nullptr)
+        gStandalone.engine->setFileCallback(func, ptr);
 }
 
 // -------------------------------------------------------------------------------------------------------------------

source/carla

@@ -333,8 +333,8 @@ if __name__ == '__main__':
 
     Carla.gui = CarlaHostW()
 
-    # set our gui as transient for all plugins UIs
-    Carla.host.set_engine_option(ENGINE_OPTION_DEBUG, -1729, str(Carla.gui.winId()))
+    # set our gui as parent for all plugins UIs
+    Carla.host.set_engine_option(ENGINE_OPTION_FRONTEND_WIN_ID, 0, str(Carla.gui.winId()))
 
     # -------------------------------------------------------------
     # Load project file if set

source/carla-patchbay

@@ -87,8 +87,8 @@ if __name__ == '__main__':
 
     Carla.gui = CarlaHostW()
 
-    # set our gui as transient for all plugins UIs
-    Carla.host.set_engine_option(ENGINE_OPTION_DEBUG, -1729, str(Carla.gui.winId()))
+    # set our gui as parent for all plugins UIs
+    Carla.host.set_engine_option(ENGINE_OPTION_FRONTEND_WIN_ID, 0, str(Carla.gui.winId()))
 
     # -------------------------------------------------------------
     # Load project file if set

source/carla-plugin

@@ -742,9 +742,18 @@ if __name__ == '__main__':
 
     initHost("Carla-Plugin")
 
+    # set our gui as parent for all plugins UIs
+    Carla.host.set_engine_option(ENGINE_OPTION_FRONTEND_WIN_ID, 0, str(Carla.gui.winId()))
+
+    # simulate an engire started callback
     engineCallback(None, ENGINE_CALLBACK_ENGINE_STARTED, 0, ENGINE_PROCESS_MODE_CONTINUOUS_RACK, ENGINE_TRANSPORT_MODE_PLUGIN, 0.0, "Plugin")
 
     # -------------------------------------------------------------
     # App-Loop
 
-    sys.exit(app.exec_())
+    ret = app.exec_()
+
+    # disable parenting
+    Carla.host.set_engine_option(ENGINE_OPTION_FRONTEND_WIN_ID, 0, "0")
+
+    sys.exit(ret)

source/carla-rack

@@ -87,8 +87,8 @@ if __name__ == '__main__':
 
     Carla.gui = CarlaHostW()
 
-    # set our gui as transient for all plugins UIs
-    Carla.host.set_engine_option(ENGINE_OPTION_DEBUG, -1729, str(Carla.gui.winId()))
+    # set our gui as parent for all plugins UIs
+    Carla.host.set_engine_option(ENGINE_OPTION_FRONTEND_WIN_ID, 0, str(Carla.gui.winId()))
 
     # -------------------------------------------------------------
     # Load project file if set

source/carla_backend.py

@@ -726,6 +726,9 @@ ENGINE_OPTION_PATH_BINARIES = 13
 # @note Must be set for some internal plugins to work
 ENGINE_OPTION_PATH_RESOURCES = 14
 
+# Set frontend winId, used to define as parent window for plugin UIs.
+ENGINE_OPTION_FRONTEND_WIN_ID = 15
+
 # ------------------------------------------------------------------------------------------------------------
 # Engine Process Mode
 # Engine process mode.
@@ -767,6 +770,22 @@ ENGINE_TRANSPORT_MODE_PLUGIN = 2
 # Special mode, used in plugin-bridges only.
 ENGINE_TRANSPORT_MODE_BRIDGE = 3
 
+# ------------------------------------------------------------------------------------------------------------
+# File Callback Opcode
+# File callback opcodes.
+# Front-ends must always block-wait for user input.
+# @see FileCallbackFunc and carla_set_file_callback()
+
+# Debug.
+# This opcode is undefined and used only for testing purposes.
+FILE_CALLBACK_DEBUG = 0
+
+# Open file or folder.
+FILE_CALLBACK_OPEN = 1
+
+# Save file or folder.
+FILE_CALLBACK_SAVE = 2
+
 # ------------------------------------------------------------------------------------------------------------
 # Patchbay Icon
 # The icon of a patchbay client/group.
@@ -803,6 +822,10 @@ PATCHBAY_ICON_FILE = 5
 # @see EngineCallbackOpcode and carla_set_engine_callback()
 EngineCallbackFunc = CFUNCTYPE(None, c_void_p, c_enum, c_uint, c_int, c_int, c_float, c_char_p)
 
+# File callback function.
+# @see FileCallbackOpcode
+FileCallbackFunc = CFUNCTYPE(c_char_p, c_void_p, c_enum, c_bool, c_char_p, c_char_p)
+
 # Parameter data.
 class ParameterData(Structure):
     _fields_ = [
@@ -939,29 +962,9 @@ PyEngineDriverDeviceInfo = {
     'sampleRates': []
 }
 
-# ------------------------------------------------------------------------------------------------------------
-# File Callback Opcode
-# File callback opcodes.
-# Front-ends must always block-wait for user input.
-# @see FileCallbackFunc and carla_set_file_callback()
-
-# Debug.
-# This opcode is undefined and used only for testing purposes.
-FILE_CALLBACK_DEBUG = 0
-
-# Open file or folder.
-FILE_CALLBACK_OPEN = 1
-
-# Save file or folder.
-FILE_CALLBACK_SAVE = 2
-
 # ------------------------------------------------------------------------------------------------------------
 # Carla Host API (C stuff)
 
-# File callback function.
-# @see FileCallbackOpcode
-FileCallbackFunc = CFUNCTYPE(c_char_p, c_void_p, c_enum, c_bool, c_char_p, c_char_p)
-
 # Information about a loaded plugin.
 # @see carla_get_plugin_info()
 class CarlaPluginInfo(Structure):

source/utils/CarlaBackendUtils.hpp

@@ -314,6 +314,8 @@ const char* EngineOption2Str(const EngineOption option) noexcept
         return "ENGINE_OPTION_PATH_BINARIES";
     case ENGINE_OPTION_PATH_RESOURCES:
         return "ENGINE_OPTION_PATH_RESOURCES";
+    case ENGINE_OPTION_FRONTEND_WIN_ID:
+        return "ENGINE_OPTION_FRONTEND_WIN_ID";
     }
 
     carla_stderr("CarlaBackend::EngineOption2Str(%i) - invalid option", option);