Implement part of the XEmbed protocol

src/wine-host/editor.cpp

@@ -1,10 +1,23 @@
 #include "editor.h"
 
+constexpr char xembed_info_proeprty[] = "_XEMBED_INFO";
+
 ATOM register_window_class(std::string window_class_name);
 
 Editor::Editor(std::string window_class_name)
     : window_class(register_window_class(window_class_name)),
-      x11_connection(xcb_connect(nullptr, nullptr), &xcb_disconnect) {}
+      x11_connection(xcb_connect(nullptr, nullptr), &xcb_disconnect) {
+    // We need a bunch of property atoms for the XEmbed protocol
+    xcb_generic_error_t* err;
+
+    const auto xembed_info_cookie =
+        xcb_intern_atom(x11_connection.get(), 0, strlen(xembed_info_proeprty),
+                        xembed_info_proeprty);
+
+    xcb_xembed_info =
+        xcb_intern_atom_reply(x11_connection.get(), xembed_info_cookie, &err)
+            ->atom;
+}
 
 HWND Editor::open() {
     // Create a window without any decoratiosn for easy embedding. The
@@ -49,14 +62,23 @@ bool Editor::embed_into(const size_t parent_window_handle) {
         return false;
     }
 
+    // This follows the embedding procedure specified in the XEmbed sped:
+    // https://specifications.freedesktop.org/xembed-spec/xembed-spec-latest.html
+    // under 'Embedding life cycle
+    // Sadly there's doesn't seem to be any implementation of this available as
+    // a library
     const size_t child_window_handle = get_x11_handle().value();
 
-    // TODO: Reparenting works, but the Wine window is not updating so that
-    //       might cause it to look like it doesn't work
     xcb_reparent_window(x11_connection.get(), child_window_handle,
                         parent_window_handle, 0, 0);
 
-    // TODO: Is this needed?
+    // This tells the WM that the parent window embedding and mapping/uumapping
+    // a child window. Requires the PROPERTY_NOTIFY event.
+    std::array<int, 2> xembed_info_values{0, 1};
+    xcb_change_property(x11_connection.get(), XCB_PROP_MODE_REPLACE,
+                        parent_window_handle, xcb_xembed_info, xcb_xembed_info,
+                        32, 2, xembed_info_values.data());
+
     const int parent_events = XCB_EVENT_MASK_SUBSTRUCTURE_REDIRECT |
                               XCB_EVENT_MASK_SUBSTRUCTURE_NOTIFY |
                               XCB_EVENT_MASK_STRUCTURE_NOTIFY;
@@ -69,14 +91,16 @@ bool Editor::embed_into(const size_t parent_window_handle) {
     xcb_change_window_attributes(x11_connection.get(), child_window_handle,
                                  XCB_CW_EVENT_MASK, &child_events);
 
+    // TODO: Send XEMBED_EMBEDDED_NOTIFY XEMBED_FOCUS_IN, XEMBED_WINDOW_ACTIVATE
+    //       and XEMBED_MODALITY_ON from the parent window Before or after
+    //       embedding?
+
     // TODO: Is this map needed?
     xcb_map_window(x11_connection.get(), child_window_handle);
     xcb_flush(x11_connection.get());
 
-    ShowWindow(win32_handle->get(), SW_SHOWNORMAL);
-    // TODO: We should just immediatly resize the window to the right size
-    //       isntead
-    UpdateWindow(win32_handle->get());
+    // TODO: Should this be done before reparenting and mapping?
+    ShowWindow(win32_handle->get(), SW_SHOW);
 
     return true;
 }

src/wine-host/editor.h

@@ -84,4 +84,5 @@ class Editor {
         win32_handle;
 
     std::unique_ptr<xcb_connection_t, decltype(&xcb_disconnect)> x11_connection;
+    xcb_atom_t xcb_xembed_info;
 };