Move event handling to a common HostBridge

meson.build

@@ -238,6 +238,7 @@ host_sources = [
   'src/common/logging/vst2.cpp',
   'src/common/plugins.cpp',
   'src/common/utils.cpp',
+  'src/wine-host/bridges/common.cpp',
   'src/wine-host/bridges/vst2.cpp',
   'src/wine-host/editor.cpp',
   'src/wine-host/editor.cpp',

src/wine-host/bridges/common.cpp

@@ -0,0 +1,38 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020  Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#include "common.h"
+
+void HostBridge::handle_win32_events() {
+    if (editor) {
+        editor->handle_win32_events();
+    } else {
+        MSG msg;
+
+        for (int i = 0; i < max_win32_messages &&
+                        PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
+             i++) {
+            TranslateMessage(&msg);
+            DispatchMessage(&msg);
+        }
+    }
+}
+
+void HostBridge::handle_x11_events() {
+    if (editor) {
+        editor->handle_x11_events();
+    }
+}

src/wine-host/bridges/common.h

@@ -0,0 +1,61 @@
+// yabridge: a Wine VST bridge
+// Copyright (C) 2020  Robbert van der Helm
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+#pragma once
+
+#include "../editor.h"
+
+/**
+ * The base for the Wine plugin host bridge interface for all plugin types. This
+ * only has to be able to handle Win32 and X11 events. Implementations of this
+ * will actually host a plugin and do all the function call forwarding.
+ */
+class HostBridge {
+   public:
+    /**
+     * Handle X11 events for the editor window if it is open. This can safely be
+     * run from any thread.
+     */
+    void handle_x11_events();
+
+    /**
+     * Run the message loop for this plugin. This is only used for the
+     * individual plugin host, so that we can filter out some unnecessary timer
+     * events. When hosting multiple plugins, a simple central message loop
+     * should be used instead. This is run on a timer in the same IO context as
+     * the one that handles the events, i.e. `main_context`.
+     *
+     * Because of the way the Win32 API works we have to process events on the
+     * same thread as the one the window was created on, and that thread is the
+     * thread that's handling dispatcher calls. Some plugins will also rely on
+     * the Win32 message loop to run tasks on a timer and to defer loading, so
+     * we have to make sure to always run this loop. The only exception is a in
+     * specific situation that can cause a race condition in some plugins
+     * because of incorrect assumptions made by the plugin. See the dostring for
+     * `HostBridge::editor` for more information.
+     */
+    void handle_win32_events();
+
+   protected:
+    /**
+     * The plugin editor window. Allows embedding the plugin's editor into a
+     * Wine window, and embedding that Wine window into a window provided by the
+     * host. Should be empty when the editor is not open.
+     *
+     * @see should_postpone_message_loop
+     */
+    std::optional<Editor> editor;
+};

src/wine-host/bridges/vst2.cpp

@@ -392,27 +392,6 @@ intptr_t Vst2Bridge::dispatch_wrapper(AEffect* plugin,
     }
 }
 
-void Vst2Bridge::handle_win32_events() {
-    if (editor) {
-        editor->handle_win32_events();
-    } else {
-        MSG msg;
-
-        for (int i = 0; i < max_win32_messages &&
-                        PeekMessage(&msg, nullptr, 0, 0, PM_REMOVE);
-             i++) {
-            TranslateMessage(&msg);
-            DispatchMessage(&msg);
-        }
-    }
-}
-
-void Vst2Bridge::handle_x11_events() {
-    if (editor) {
-        editor->handle_x11_events();
-    }
-}
-
 class HostCallbackDataConverter : DefaultDataConverter {
    public:
     HostCallbackDataConverter(AEffect* plugin,

src/wine-host/bridges/vst2.h

@@ -31,22 +31,14 @@
 
 #include "../../common/communication/vst2.h"
 #include "../../common/configuration.h"
-#include "../editor.h"
 #include "../utils.h"
+#include "common.h"
 
 /**
  * This hosts a Windows VST2 plugin, forwards messages sent by the Linux VST
  * plugin and provides host callback function for the plugin to talk back.
- *
- * @remark Because of Win32 API limitations, all window handling has to be done
- *   from a single thread. Most plugins won't have any issues when using
- *   multiple message loops, but the Melda plugins for instance will only update
- *   their GUIs from the message loop of the thread that created the first
- *   instance. This is why we pass an IO context to this class so everything
- *   that's not performance critical (audio and midi event handling) is handled
- *   on the same thread, even when hosting multiple plugins.
  */
-class Vst2Bridge {
+class Vst2Bridge : public HostBridge {
    public:
     /**
      * Initializes the Windows VST plugin and set up communication with the
@@ -83,30 +75,6 @@ class Vst2Bridge {
      */
     void handle_dispatch();
 
-    /**
-     * Handle X11 events for the editor window if it is open. This can safely be
-     * run from any thread.
-     */
-    void handle_x11_events();
-
-    /**
-     * Run the message loop for this plugin. This is only used for the
-     * individual plugin host, so that we can filter out some unnecessary timer
-     * events. When hosting multiple plugins, a simple central message loop
-     * should be used instead. This is run on a timer in the same IO context as
-     * the one that handles the events, i.e. `main_context`.
-     *
-     * Because of the way the Win32 API works we have to process events on the
-     * same thread as the one the window was created on, and that thread is the
-     * thread that's handling dispatcher calls. Some plugins will also rely on
-     * the Win32 message loop to run tasks on a timer and to defer loading, so
-     * we have to make sure to always run this loop. The only exception is a in
-     * specific situation that can cause a race condition in some plugins
-     * because of incorrect assumptions made by the plugin. See the dostring for
-     * `Vst2Bridge::editor` for more information.
-     */
-    void handle_win32_events();
-
     /**
      * Forward the host callback made by the plugin to the host and return the
      * results.
@@ -203,13 +171,4 @@ class Vst2Bridge {
      * now happens in two different threads.
      */
     std::mutex next_buffer_midi_events_mutex;
-
-    /**
-     * The plugin editor window. Allows embedding the plugin's editor into a
-     * Wine window, and embedding that Wine window into a window provided by the
-     * host. Should be empty when the editor is not open.
-     *
-     * @see should_postpone_message_loop
-     */
-    std::optional<Editor> editor;
 };