Add a way to invoke code from the GUI

Author: abique

plugins/core-plugin.cc

@@ -363,6 +363,12 @@ namespace clap {
       });
    }
 
+   void CorePlugin::onGuiInvoke(
+      const std::string &method,
+      const std::vector<std::variant<bool, int64_t, double, std::string>> &args) {
+      std::cerr << "Unhandled gui method invocation: " << method << std::endl;
+   }
+
 #endif // CLAP_PLUGINS_HEADLESS
 
    //------------------//

plugins/core-plugin.hh

@@ -180,6 +180,9 @@ namespace clap {
       void onGuiWindowClosed(bool wasDestroyed) override;
       void onGuiUndo() override;
       void onGuiRedo() override;
+      void onGuiInvoke(
+         const std::string &method,
+         const std::vector<std::variant<bool, int64_t, double, std::string>> &args) override;
 #endif
 
       //------------------------//

plugins/gui/abstract-gui-listener.hh

@@ -1,8 +1,15 @@
 #pragma once
 
+#include <string>
+#include <variant>
+#include <vector>
+
 #include <clap/clap.h>
 
 namespace clap {
+   using InvocationArgumentType = std::variant<bool, int64_t, double, std::string>;
+   using InvocationArgumentsType = std::vector<InvocationArgumentType>;
+
    // Listener for events produced by the Gui, to the destination of the plugin.
    //
    // Beaware that the callbacks happen on the plugin's GUI thread, not the host's main thread.
@@ -24,5 +31,7 @@ namespace clap {
 
       virtual void onGuiUndo() = 0;
       virtual void onGuiRedo() = 0;
+
+      virtual void onGuiInvoke(const std::string &method, const InvocationArgumentsType &args) = 0;
    };
 } // namespace clap

plugins/gui/plugin-proxy.cc

@@ -1,6 +1,7 @@
 #include "plugin-proxy.hh"
-#include "gui.hh"
 #include "../modules/module.hh"
+#include "abstract-gui-listener.hh"
+#include "gui.hh"
 
 namespace clap {
    PluginProxy::PluginProxy(Gui &client) : super(&client), _client(client) {}
@@ -26,4 +27,23 @@ namespace clap {
       if (!it.second)
          it.first->second->redefine(info);
    }
+
+   void PluginProxy::invoke(const QString &method) {
+      _client.guiListener().onGuiInvoke(method.toStdString(), {});
+   }
+
+   void PluginProxy::invoke(const QString &method, const QVariantList &args) {
+      InvocationArgumentsType targetArgs;
+      for (auto &a : args) {
+         if (get_if<double>(&a))
+            targetArgs.push_back(get<double>(a));
+         else if (get_if<int64_t>(&a))
+            targetArgs.push_back(get<int64_t>(a));
+         else if (get_if<bool>(&a))
+            targetArgs.push_back(get<bool>(a));
+         else if (get_if<QString>(&a))
+            targetArgs.push_back(get<QString>(a).toStdString());
+      }
+      _client.guiListener().onGuiInvoke(method.toStdString(), targetArgs);
+   }
 } // namespace clap

plugins/gui/plugin-proxy.hh

@@ -24,6 +24,8 @@ namespace clap {
       Q_INVOKABLE ParameterProxy *param(clap_id paramId);
       Q_INVOKABLE ParameterProxy *param(clap_id moduleId, clap_id paramId);
       Q_INVOKABLE QString toString() const;
+      Q_INVOKABLE void invoke(const QString &method);
+      Q_INVOKABLE void invoke(const QString &method, const QVariantList &args);
 
    private:
       Gui &_client;

plugins/gui/qml/clap/skins/undo-test/main.qml

@@ -31,5 +31,9 @@ Rectangle {
                         text: undo.redoName
                 }
         }
+        Button {
+                text: "Do something"
+                onClicked: plugin.invoke("incrementState")
+        }
     }
 }

plugins/plugs/undo-test/undo-test.cc

@@ -92,6 +92,7 @@ namespace clap {
       delta.new_value = ++_state;
       _host.undoChangeMade("inc", &delta, sizeof(delta), true);
    }
+
    bool UndoTest::init() noexcept {
       if (!super::init())
          return false;
@@ -101,4 +102,13 @@ namespace clap {
       }
       return true;
    }
+
+   void UndoTest::onGuiInvoke(
+      const std::string &method,
+      const std::vector<std::variant<bool, int64_t, double, std::string>> &args) {
+      if (method == "incrementState")
+         incrementState();
+      else
+         super::onGuiInvoke(method, args);
+   }
 } // namespace clap

plugins/plugs/undo-test/undo-test.hh

@@ -1,7 +1,7 @@
 #pragma once
 
-#include <string>
 #include <optional>
+#include <string>
 
 #include "../../core-plugin.hh"
 
@@ -25,6 +25,12 @@ namespace clap {
 
       void incrementState();
 
+#ifndef CLAP_PLUGINS_HEADLESS
+      void onGuiInvoke(
+         const std::string &method,
+         const std::vector<std::variant<bool, int64_t, double, std::string>> &args) override;
+#endif
+
    private:
       uint32_t _state{0};
    };