commit 0ff31668a1117cf784e41331105d5c76f9bc441f
Author:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
AuthorDate: Thu Sep 8 16:11:53 2022 +0200
Commit:     ManoloFLTK <41016272+ManoloFLTK@users.noreply.github.com>
CommitDate: Thu Sep 8 16:11:53 2022 +0200

    Wayland: remove memory leak from missing wl_callback_destroy() call.
    
    This hopefully corresponds to the memory leak mentioned in fltk.general
    named "FLTK and Wayland".

 src/drivers/Wayland/Fl_Wayland_Graphics_Driver.H   |  3 ++-
 src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx | 13 ++++++-------
 src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx   | 16 +++++++++++++++-
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git src/drivers/Wayland/Fl_Wayland_Graphics_Driver.H src/drivers/Wayland/Fl_Wayland_Graphics_Driver.H
index 9b2edba..855bce1 100644
--- src/drivers/Wayland/Fl_Wayland_Graphics_Driver.H
+++ src/drivers/Wayland/Fl_Wayland_Graphics_Driver.H
@@ -78,7 +78,8 @@ public:
   virtual void copy_offscreen(int x, int y, int w, int h, Fl_Offscreen osrc, int srcx, int srcy);
   static struct fl_wld_buffer *create_shm_buffer(int width, int height);
   static void buffer_release(struct wld_window *window);
-  static void buffer_commit(struct wld_window *window, const struct wl_callback_listener*);
+  static void buffer_commit(struct wld_window *window, const struct wl_callback_listener*,
+                            bool need_damage = true);
   static void cairo_init(struct fl_wld_buffer *buffer, int width, int height, int stride, cairo_format_t format);
   virtual void *gc();
   virtual void gc(void *gc);
diff --git src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx
index 031c44e..e4632b4 100644
--- src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx
+++ src/drivers/Wayland/Fl_Wayland_Graphics_Driver.cxx
@@ -76,18 +76,16 @@ struct fl_wld_buffer *Fl_Wayland_Graphics_Driver::create_shm_buffer(int width, i
 
 
 void Fl_Wayland_Graphics_Driver::buffer_commit(struct wld_window *window,
-                                               const struct wl_callback_listener *listener) {
+                                               const struct wl_callback_listener *listener,
+                                               bool need_damage) {
   cairo_surface_t *surf = cairo_get_target(window->buffer->cairo_);
   cairo_surface_flush(surf);
   memcpy(window->buffer->data, window->buffer->draw_buffer, window->buffer->data_size);
   wl_surface_attach(window->wl_surface, window->buffer->wl_buffer, 0, 0);
   wl_surface_set_buffer_scale(window->wl_surface, window->scale);
-  struct wl_callback *cb = wl_surface_frame(window->wl_surface);
-  if (listener) {
-    window->buffer->cb = cb;
-    wl_surface_damage_buffer(window->wl_surface, 0, 0, 1000000, 1000000);
-    wl_callback_add_listener(window->buffer->cb, listener, window);
-  }
+  window->buffer->cb = wl_surface_frame(window->wl_surface);
+  if (need_damage) wl_surface_damage_buffer(window->wl_surface, 0, 0, 1000000, 1000000);
+  wl_callback_add_listener(window->buffer->cb, listener, window);
   wl_surface_commit(window->wl_surface);
   window->buffer->draw_buffer_needs_commit = false;
 //fprintf(stderr,"buffer_commit %s\n", window->fl_win->parent()?"child":"top");
@@ -117,6 +115,7 @@ void Fl_Wayland_Graphics_Driver::cairo_init(struct fl_wld_buffer *buffer, int wi
 void Fl_Wayland_Graphics_Driver::buffer_release(struct wld_window *window)
 {
   if (window->buffer) {
+    if (window->buffer->cb) wl_callback_destroy(window->buffer->cb);
     wl_buffer_destroy(window->buffer->wl_buffer);
     delete[] window->buffer->draw_buffer;
     window->buffer->draw_buffer = NULL;
diff --git src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
index 2692e8a..72430c8 100644
--- src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
+++ src/drivers/Wayland/Fl_Wayland_Window_Driver.cxx
@@ -382,6 +382,18 @@ void Fl_Wayland_Window_Driver::make_current() {
 }
 
 
+// used to support regular drawing
+static void surface_frame_one_shot(void *data, struct wl_callback *cb, uint32_t time) {
+  wl_callback_destroy(cb);
+  struct wld_window *window = (struct wld_window *)data;
+  window->buffer->cb = NULL;
+}
+
+static const struct wl_callback_listener surface_frame_listener_one_shot = {
+  .done = surface_frame_one_shot,
+};
+
+
 void Fl_Wayland_Window_Driver::flush() {
   if (!pWindow->damage()) return;
   if (pWindow->as_gl_window()) {
@@ -420,7 +432,9 @@ void Fl_Wayland_Window_Driver::flush() {
   Fl_Window_Driver::flush();
   Fl_Wayland_Window_Driver::in_flush = false;
 
-  Fl_Wayland_Graphics_Driver::buffer_commit(window, NULL);
+  if (!window->buffer->cb) {
+    Fl_Wayland_Graphics_Driver::buffer_commit(window, &surface_frame_listener_one_shot, false);
+  }
 }