[Bf-blender-cvs] [ed663219965] master: GHOST/Wayland: simplify logic for disconnecting monitors under Wayland

[Campbell Barton]

Commit: ed663219965bd79e410df23a1dd2b52decd9efa0
Author: Campbell Barton
Date:   Tue Jan 10 17:43:20 2023 +1100
Branches: master
https://developer.blender.org/rBed663219965bd79e410df23a1dd2b52decd9efa0

GHOST/Wayland: simplify logic for disconnecting monitors under Wayland

The T103586 fix effectively ran the wl_surface_listener.leave callback
to as WLROOTS based compositors doesn't run them. Remove the workaround
since it's an error in WLROOTS to be fixed upstream.

Temporarily using the wrong window scale when disconnecting a monitor
on configurations that use different DPI per monitor is a minor enough
issue that I don't think it makes sense to workaround in GHOST.

===================================================================

M	intern/ghost/intern/GHOST_SystemWayland.cpp
M	intern/ghost/intern/GHOST_SystemWayland.h

===================================================================

diff --git a/intern/ghost/intern/GHOST_SystemWayland.cpp b/intern/ghost/intern/GHOST_SystemWayland.cpp
index 251466d9501..d823db2afd7 100644
--- a/intern/ghost/intern/GHOST_SystemWayland.cpp
+++ b/intern/ghost/intern/GHOST_SystemWayland.cpp
@@ -4534,7 +4534,7 @@ static void output_handle_scale(void *data, struct wl_output * /*wl_output*/, co
   CLOG_INFO(LOG, 2, "scale");
   GWL_Output *output = static_cast<GWL_Output *>(data);
   output->scale = factor;
-  output->system->output_scale_update_maybe_leave(output, false);
+  output->system->output_scale_update(output);
 }
 
 static const struct wl_output_listener output_listener = {
@@ -4736,7 +4736,11 @@ static void gwl_registry_wl_output_remove(GWL_Display *display,
 
   if (!on_exit) {
     /* Needed for WLROOTS, does nothing if surface leave callbacks have already run. */
-    output->system->output_scale_update_maybe_leave(output, true);
+    if (output->system->output_unref(output->wl_output)) {
+      CLOG_WARN(LOG,
+                "mis-behaving compositor failed to call \"surface_listener.leave\" "
+                "window scale may be invalid!");
+    }
   }
 
   if (output->xdg_output) {
@@ -6744,11 +6748,13 @@ void GHOST_SystemWayland::seat_active_set(const struct GWL_Seat *seat)
   gwl_display_seat_active_set(display_, seat);
 }
 
-void GHOST_SystemWayland::window_surface_unref(const wl_surface *wl_surface)
+bool GHOST_SystemWayland::window_surface_unref(const wl_surface *wl_surface)
 {
+  bool changed = false;
 #define SURFACE_CLEAR_PTR(surface_test) \
   if (surface_test == wl_surface) { \
     surface_test = nullptr; \
+    changed = true; \
   } \
   ((void)0);
 
@@ -6760,37 +6766,62 @@ void GHOST_SystemWayland::window_surface_unref(const wl_surface *wl_surface)
     SURFACE_CLEAR_PTR(seat->wl_surface_window_focus_dnd);
   }
 #undef SURFACE_CLEAR_PTR
+
+  return changed;
 }
 
-void GHOST_SystemWayland::output_scale_update_maybe_leave(GWL_Output *output, bool leave)
+bool GHOST_SystemWayland::output_unref(wl_output *wl_output)
 {
-  /* Update scale, optionally leaving the outputs beforehand. */
-  GHOST_WindowManager *window_manager = output->system->getWindowManager();
+  bool changed = false;
+  if (!ghost_wl_output_own(wl_output)) {
+    return changed;
+  }
+
+  /* NOTE: keep in sync with `output_scale_update`. */
+  GWL_Output *output = ghost_wl_output_user_data(wl_output);
+  GHOST_WindowManager *window_manager = getWindowManager();
+  if (window_manager) {
+    for (GHOST_IWindow *iwin : window_manager->getWindows()) {
+      GHOST_WindowWayland *win = static_cast<GHOST_WindowWayland *>(iwin);
+      if (win->outputs_leave(output)) {
+        changed = true;
+      }
+    }
+  }
+  for (GWL_Seat *seat : display_->seats) {
+    if (seat->pointer.outputs.erase(output)) {
+      changed = true;
+    }
+    if (seat->tablet.outputs.erase(output)) {
+      changed = true;
+    }
+  }
+  return changed;
+}
+
+void GHOST_SystemWayland::output_scale_update(GWL_Output *output)
+{
+  /* NOTE: keep in sync with `output_unref`. */
+  GHOST_WindowManager *window_manager = getWindowManager();
   if (window_manager) {
     for (GHOST_IWindow *iwin : window_manager->getWindows()) {
       GHOST_WindowWayland *win = static_cast<GHOST_WindowWayland *>(iwin);
       const std::vector<GWL_Output *> &outputs = win->outputs();
-      bool found = leave ? win->outputs_leave(output) :
-                           !(std::find(outputs.begin(), outputs.end(), output) == outputs.cend());
-      if (found) {
+      if (!(std::find(outputs.begin(), outputs.end(), output) == outputs.cend())) {
         win->outputs_changed_update_scale();
       }
     }
   }
 
   for (GWL_Seat *seat : display_->seats) {
-    bool found;
-
-    found = leave ? seat->pointer.outputs.erase(output) : seat->pointer.outputs.count(output);
-    if (found) {
+    if (seat->pointer.outputs.count(output)) {
       if (seat->cursor.wl_surface_cursor != nullptr) {
         update_cursor_scale(
             seat->cursor, seat->system->wl_shm(), &seat->pointer, seat->cursor.wl_surface_cursor);
       }
     }
 
-    found = leave ? seat->tablet.outputs.erase(output) : seat->tablet.outputs.count(output);
-    if (found) {
+    if (seat->tablet.outputs.count(output)) {
       for (struct zwp_tablet_tool_v2 *zwp_tablet_tool_v2 : seat->tablet_tools) {
         GWL_TabletTool *tablet_tool = static_cast<GWL_TabletTool *>(
             zwp_tablet_tool_v2_get_user_data(zwp_tablet_tool_v2));
diff --git a/intern/ghost/intern/GHOST_SystemWayland.h b/intern/ghost/intern/GHOST_SystemWayland.h
index c102a3d7a12..c745d3b1d36 100644
--- a/intern/ghost/intern/GHOST_SystemWayland.h
+++ b/intern/ghost/intern/GHOST_SystemWayland.h
@@ -194,10 +194,25 @@ class GHOST_SystemWayland : public GHOST_System {
   /** Set this seat to be active. */
   void seat_active_set(const struct GWL_Seat *seat);
 
-  void output_scale_update_maybe_leave(GWL_Output *output, bool leave);
+  /**
+   * Clear all references to this output.
+   *
+   * \note The compositor should have already called the `wl_surface_listener.leave` callback,
+   * however some compositors may not (see T103586).
+   * So remove references to the output before it's destroyed to avoid crashing.
+   *
+   * \return true when any references were removed.
+   */
+  bool output_unref(struct wl_output *wl_output);
 
-  /** Clear all references to this surface to prevent accessing NULL pointers. */
-  void window_surface_unref(const wl_surface *wl_surface);
+  void output_scale_update(GWL_Output *output);
+
+  /**
+   * Clear all references to this surface to prevent accessing NULL pointers.
+   *
+   * \return true when any references were removed.
+   */
+  bool window_surface_unref(const wl_surface *wl_surface);
 
   bool window_cursor_grab_set(const GHOST_TGrabCursorMode mode,
                               const GHOST_TGrabCursorMode mode_current,