Wait for carla-plugin LV2 to be ready, pass widget correctly

Fixes high cpu usage with gtk2-suil hosts

source/backend/engine/CarlaEngineNative.cpp

@@ -64,7 +64,7 @@ class CarlaEngineNativeUI : public CarlaExternalUI
 public:
     CarlaEngineNativeUI(CarlaEngine* const engine)
         : fEngine(engine),
-          fIsReady(false)
+          fRemoteWinId(0)
     {
         carla_debug("CarlaEngineNativeUI::CarlaEngineNativeUI(%p)", engine);
     }
@@ -76,7 +76,12 @@ public:
 
     bool isReady() const noexcept
     {
-        return fIsReady;
+        return fRemoteWinId != 0;
+    }
+
+    intptr_t getRemoteWinId() const noexcept
+    {
+        return fRemoteWinId;
     }
 
 protected:
@@ -544,7 +549,11 @@ protected:
         }
         else if (std::strcmp(msg, "ready") == 0)
         {
-            fIsReady = true;
+            uint64_t winId;
+
+            CARLA_SAFE_ASSERT_RETURN(readNextLineAsULong(winId), true);
+
+            fRemoteWinId = static_cast<intptr_t>(winId);
         }
         else
         {
@@ -565,7 +574,7 @@ protected:
 
 private:
     CarlaEngine* const fEngine;
-    bool               fIsReady;
+    intptr_t           fRemoteWinId;
 
     void _updateParamValues(CarlaPlugin* const plugin, const uint32_t pluginId) const noexcept
     {
@@ -1521,10 +1530,13 @@ protected:
 
             if (fWaitForReadyMsg)
             {
-                carla_stdout("Using Carla plugin embedded in Tracktion, waiting for it to be ready...");
+                carla_stdout("Using Carla plugin embedded, waiting for it to be ready...");
 
                 for (; fUiServer.isPipeRunning() && ! fUiServer.isReady();)
+                {
+                    carla_msleep(25);
                     fUiServer.idlePipe();
+                }
 
                 carla_stdout("Done!");
             }
@@ -1784,7 +1796,10 @@ public:
         {
         case NATIVE_PLUGIN_OPCODE_NULL:
             if (static_cast<uint32_t>(index) == 0xDEADF00D && static_cast<uintptr_t>(value) == 0xC0C0B00B)
+            {
                 handlePtr->fWaitForReadyMsg = true;
+                return handlePtr->fUiServer.getRemoteWinId();
+            }
             return 0;
         case NATIVE_PLUGIN_OPCODE_BUFFER_SIZE_CHANGED:
             CARLA_SAFE_ASSERT_RETURN(value > 0, 0);

source/native-plugins/resources/carla-plugin

@@ -485,7 +485,7 @@ class CarlaEmbedW(QEmbedWidget):
         self.addWidget(self.gui.centralWidget())
         self.finalSetup(self.gui, winId)
 
-        self.gui.send(["ready"])
+        self.gui.send(["ready", int(self.winId())])
 
     def addShortcutActions(self, actions):
         for action in actions:

source/plugin/carla-lv2.cpp

@@ -821,9 +821,8 @@ public:
 
         if (isEmbed)
         {
-            fUI.isVisible = true;
-
             intptr_t parentId = 0;
+            const LV2UI_Resize* uiResize = nullptr;
 
             for (int i=0; features[i] != nullptr; ++i)
             {
@@ -833,20 +832,40 @@ public:
                 }
                 else if (std::strcmp(features[i]->URI, LV2_UI__resize) == 0)
                 {
-                    const LV2UI_Resize* const uiResize((const LV2UI_Resize*)features[i]->data);
-                    uiResize->ui_resize(uiResize->handle, 740, 512);
+                    uiResize = (const LV2UI_Resize*)features[i]->data;
                 }
             }
 
-            char strBuf[0xff+1];
-            strBuf[0xff] = '\0';
-            std::snprintf(strBuf, 0xff, P_INTPTR, parentId);
+            // -----------------------------------------------------------
+            // see if the host can really embed the UI
 
-            carla_setenv("CARLA_PLUGIN_EMBED_WINID", strBuf);
+            if (parentId != 0)
+            {
+                // wait for remote side to be ready
+                fDescriptor->dispatcher(fHandle, NATIVE_PLUGIN_OPCODE_NULL, (int32_t)0xDEADF00D, 0xC0C0B00B, nullptr, 0.0f);
 
-            fDescriptor->ui_show(fHandle, true);
+                if (uiResize && uiResize->ui_resize != nullptr)
+                    uiResize->ui_resize(uiResize->handle, 740, 512);
+
+                fHost.uiName = carla_strdup(fDescriptor->name);
+                fUI.isVisible = true;
+
+                char strBuf[0xff+1];
+                strBuf[0xff] = '\0';
+                std::snprintf(strBuf, 0xff, P_INTPTR, parentId);
 
-            carla_setenv("CARLA_PLUGIN_EMBED_WINID", "0");
+                carla_setenv("CARLA_PLUGIN_EMBED_WINID", strBuf);
+
+                fDescriptor->ui_show(fHandle, true);
+
+                carla_setenv("CARLA_PLUGIN_EMBED_WINID", "0");
+
+                const intptr_t winId(fDescriptor->dispatcher(fHandle, NATIVE_PLUGIN_OPCODE_NULL, (int32_t)0xDEADF00D, 0xC0C0B00B, nullptr, 0.0f));
+                CARLA_SAFE_ASSERT_RETURN(winId != 0,);
+
+                *widget = (LV2UI_Widget)winId;
+                return;
+            }
         }
 #endif
 
@@ -972,8 +991,6 @@ protected:
 
     void handleUiShow()
     {
-        CARLA_SAFE_ASSERT_RETURN(! fUI.isEmbed,);
-
         if (fDescriptor->ui_show != nullptr)
             fDescriptor->ui_show(fHandle, true);