Add an X11 event handling function to the proxy

src/wine-host/editor.cpp

@@ -374,6 +374,10 @@ void Editor::handle_x11_events() const noexcept {
     //       function calls involving it will fail. All functions called from
     //       here should be able to handle that cleanly.
     try {
+        // Pump X11 events for handling XDND client messages from the
+        // drag-and-drop proxy
+        dnd_proxy_handle.handle_x11_events();
+
         std::unique_ptr<xcb_generic_event_t> generic_event;
         while (generic_event.reset(xcb_poll_for_event(x11_connection.get())),
                generic_event != nullptr) {

src/wine-host/xdnd-proxy.cpp

@@ -188,6 +188,7 @@ void CALLBACK dnd_winevent_callback(HWINEVENTHOOK /*hWinEventHook*/,
 
 WineXdndProxy::WineXdndProxy()
     : x11_connection(xcb_connect(nullptr, nullptr), xcb_disconnect),
+      proxy_window(xcb_generate_id(x11_connection.get())),
       hook_handle(
           SetWinEventHook(EVENT_OBJECT_CREATE,
                           EVENT_OBJECT_CREATE,
@@ -196,7 +197,15 @@ WineXdndProxy::WineXdndProxy()
                           0,
                           0,
                           WINEVENT_OUTOFCONTEXT | WINEVENT_SKIPOWNPROCESS),
-          UnhookWinEvent) {}
+          UnhookWinEvent) {
+    //
+}
+
+WineXdndProxy::~WineXdndProxy() noexcept {
+    // TODO: Move this to a RAII wrapper
+    xcb_destroy_window(x11_connection.get(), proxy_window);
+    xcb_flush(x11_connection.get());
+}
 
 WineXdndProxy::Handle::Handle(WineXdndProxy* proxy) : proxy(proxy) {}
 
@@ -214,6 +223,10 @@ WineXdndProxy::Handle::Handle(Handle&& o) noexcept : proxy(o.proxy) {
     instance_reference_count += 1;
 }
 
+void WineXdndProxy::Handle::handle_x11_events() const noexcept {
+    proxy->handle_x11_events();
+}
+
 WineXdndProxy::Handle WineXdndProxy::get_handle() {
     // See the `instance` global above for an explanation on what's going on
     // here.
@@ -223,3 +236,7 @@ WineXdndProxy::Handle WineXdndProxy::get_handle() {
 
     return Handle(instance);
 }
+
+void WineXdndProxy::handle_x11_events() const noexcept {
+    // TODO
+}

src/wine-host/xdnd-proxy.h

@@ -65,6 +65,11 @@ class WineXdndProxy {
         Handle(Handle&&) noexcept;
         Handle& operator=(Handle&&) noexcept = default;
 
+        /**
+         * Handle X11 events for receiving XDND client messages.
+         */
+        void handle_x11_events() const noexcept;
+
        private:
         WineXdndProxy* proxy;
 
@@ -83,6 +88,9 @@ class WineXdndProxy {
      * in a COM object, we can only handle drag-and-drop coming form this
      * process.
      *
+     * The handle's `handle_x11_events()` method should be periodically called
+     * to pump the X11 events for handling XDND client messages.
+     *
      * This is sort of a singleton but not quite, as the `WineXdndProxy` is only
      * alive for as long as there are open editors in this process. This is done
      * to avoid opening too many X11 connections.
@@ -92,9 +100,20 @@ class WineXdndProxy {
      */
     static WineXdndProxy::Handle get_handle();
 
+    /**
+     * Handle X11 events for receiving XDND client messages.
+     */
+    void handle_x11_events() const noexcept;
+
    private:
     std::unique_ptr<xcb_connection_t, decltype(&xcb_disconnect)> x11_connection;
 
+    /**
+     * We need an unmapped proxy window to send and receive client messages for
+     * the XDND protocol.
+     */
+    xcb_window_t proxy_window;
+
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wignored-attributes"
     std::unique_ptr<std::remove_pointer_t<HWINEVENTHOOK>,