wayland: dedupe GL/VK shell-surface listeners into common code

The xdg_toplevel and libdecor configure handlers in wayland_ctx.c and
wayland_vk_ctx.c were near-identical copies: ignore_configuration
check, call into the shared *_configure_common body, clear
'configured'. The only per-backend delta is the EGL block that
resizes (or lazily creates) the wl_egl_window between the common call
and the flag clear; Vulkan takes no additional action.

Move the concrete handlers and listener structs into
wayland_common.c, parameterized by a driver_configure_handler_t hook
invoked at exactly the point the EGL block occupied.  The EGL context
passes gfx_ctx_wl_egl_configure; Vulkan passes NULL; webos ignores
the parameter as it ignored the listener before.
gfx_ctx_wl_init_common takes the handler instead of a
toplevel_listener_t, and the type, the five exported handler
declarations, the libdecor_interface extern, and the header's
libdecor.h include all become private to wayland_common.c.  Also
drops the unused zero-initialised xdg_toplevel_listener instance
from wayland_ctx.c.

Zero behavior change intended, and verified: full builds of master
and this commit (wayland + EGL + Vulkan + libdecor enabled) run under
headless Weston 13 with WAYLAND_DEBUG=1 produce structurally
identical protocol traces - the complete xdg_wm_base/xdg_surface/
xdg_toplevel init sequence, the toplevel-configure ->
surface-configure -> ack_configure -> commit cycle, and the orderly
destroy sequence are event-for-event identical after stripping
serials and timestamps (36 shell-surface events, zero-line diff).
Compile coverage includes the HAVE_LIBDECOR paths; the runtime trace
exercises the plain xdg-shell path.  The webos TU could not be
compiled here (its generated webos-shell.h requires the webos NDK
staging tree); its change is a parameter-type swap on an argument
the function never reads.

This deliberately preserves the current (protocol-questionable)
practice of applying toplevel-configure state immediately and blind-
acking xdg_surface.configure; restructuring that to latch pending
state at surface-configure time is a separate, behavior-affecting
change requiring real-compositor testing.

Net -73 lines, -368 bytes .text on the reference Linux build.

gfx/common/wayland_common.c

@@ -102,7 +102,7 @@ static bool gfx_ctx_wl_should_use_legacy_fullscreen_configure(
    return false;
 }
 
-void xdg_toplevel_handle_configure_common(gfx_ctx_wayland_data_t *wl,
+static void xdg_toplevel_handle_configure_common(gfx_ctx_wayland_data_t *wl,
       void *toplevel,
       int32_t width, int32_t height, struct wl_array *states)
 {
@@ -179,14 +179,14 @@ void xdg_toplevel_handle_configure_common(gfx_ctx_wayland_data_t *wl,
    }
 }
 
-void xdg_toplevel_handle_close(void *data,
+static void xdg_toplevel_handle_close(void *data,
       struct xdg_toplevel *xdg_toplevel)
 {
    frontend_driver_set_signal_handler_state(1);
 }
 
 #ifdef HAVE_LIBDECOR_H
-void libdecor_frame_handle_configure_common(struct libdecor_frame *frame,
+static void libdecor_frame_handle_configure_common(struct libdecor_frame *frame,
       struct libdecor_configuration *configuration,
       gfx_ctx_wayland_data_t *wl)
 {
@@ -265,15 +265,61 @@ void libdecor_frame_handle_configure_common(struct libdecor_frame *frame,
    }
 }
 
-void libdecor_frame_handle_close(struct libdecor_frame *frame,
+static void libdecor_frame_handle_close(struct libdecor_frame *frame,
       void *data)
 {
    frontend_driver_set_signal_handler_state(1);
 }
-void libdecor_frame_handle_commit(struct libdecor_frame *frame,
+static void libdecor_frame_handle_commit(struct libdecor_frame *frame,
       void *data) { }
+
+static void libdecor_frame_handle_configure(struct libdecor_frame *frame,
+      struct libdecor_configuration *configuration, void *data)
+{
+   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;
+   if (wl->ignore_configuration)
+      return;
+   libdecor_frame_handle_configure_common(frame, configuration, wl);
+   if (wl->driver_configure_handler)
+      wl->driver_configure_handler(wl);
+   wl->configured = false;
+}
+
+static void libdecor_handle_err(struct libdecor *context,
+      enum libdecor_error err, const char *message)
+{
+   RARCH_ERR("[Wayland] libdecor Caught error (%d): %s.\n", err, message);
+}
+
+static const struct libdecor_interface libdecor_interface = {
+   .error = libdecor_handle_err,
+};
+
+static const struct libdecor_frame_interface wl_libdecor_frame_interface = {
+   libdecor_frame_handle_configure,
+   libdecor_frame_handle_close,
+   libdecor_frame_handle_commit,
+};
 #endif
 
+static void xdg_toplevel_handle_configure(void *data,
+      struct xdg_toplevel *toplevel,
+      int32_t width, int32_t height, struct wl_array *states)
+{
+   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;
+   if (wl->ignore_configuration)
+      return;
+   xdg_toplevel_handle_configure_common(wl, toplevel, width, height, states);
+   if (wl->driver_configure_handler)
+      wl->driver_configure_handler(wl);
+   wl->configured = false;
+}
+
+static const struct xdg_toplevel_listener wl_xdg_toplevel_listener = {
+   xdg_toplevel_handle_configure,
+   xdg_toplevel_handle_close,
+};
+
 void gfx_ctx_wl_get_video_size_common(void *data,
       unsigned *width, unsigned *height)
 {
@@ -729,7 +775,8 @@ static bool wl_draw_splash_screen(gfx_ctx_wayland_data_t *wl)
 #endif
 
 bool gfx_ctx_wl_init_common(
-      const toplevel_listener_t *toplevel_listener, gfx_ctx_wayland_data_t **wwl)
+      driver_configure_handler_t driver_configure_handler,
+      gfx_ctx_wayland_data_t **wwl)
 {
    int i;
    gfx_ctx_wayland_data_t *wl;
@@ -752,6 +799,8 @@ bool gfx_ctx_wl_init_common(
 #endif
 #endif
 
+   wl->driver_configure_handler = driver_configure_handler;
+
    wl_list_init(&wl->all_outputs);
    wl_list_init(&wl->current_outputs);
 
@@ -896,7 +945,7 @@ bool gfx_ctx_wl_init_common(
 
    if (wl->libdecor)
    {
-      wl->libdecor_frame = wl->libdecor_decorate(wl->libdecor_context, wl->surface, &toplevel_listener->libdecor_frame_interface, wl);
+      wl->libdecor_frame = wl->libdecor_decorate(wl->libdecor_context, wl->surface, &wl_libdecor_frame_interface, wl);
       if (!wl->libdecor_frame)
       {
          RARCH_ERR("[Wayland] Failed to create libdecor frame.\n");
@@ -942,7 +991,7 @@ bool gfx_ctx_wl_init_common(
       xdg_surface_add_listener(wl->xdg_surface, &xdg_surface_listener, wl);
 
       wl->xdg_toplevel = xdg_surface_get_toplevel(wl->xdg_surface);
-      xdg_toplevel_add_listener(wl->xdg_toplevel, &toplevel_listener->xdg_toplevel_listener, wl);
+      xdg_toplevel_add_listener(wl->xdg_toplevel, &wl_xdg_toplevel_listener, wl);
 
       xdg_toplevel_set_app_id(wl->xdg_toplevel, WAYLAND_APP_ID);
       xdg_toplevel_set_title(wl->xdg_toplevel, DEFAULT_WINDOW_TITLE);
@@ -1204,20 +1253,6 @@ static void xdg_surface_handle_configure(void *data,
 }
 #endif
 
-#ifdef HAVE_LIBDECOR_H
-static void libdecor_handle_err(struct libdecor *context,
-      enum libdecor_error err, const char *message)
-{
-   RARCH_ERR("[Wayland] libdecor Caught error (%d): %s.\n", err, message);
-}
-#endif
-
 const struct wl_buffer_listener shm_buffer_listener = {
    shm_buffer_handle_release,
 };
-
-#ifdef HAVE_LIBDECOR_H
-const struct libdecor_interface libdecor_interface = {
-   .error = libdecor_handle_err,
-};
-#endif

gfx/common/wayland_common.h

@@ -15,22 +15,10 @@
 
 #pragma once
 
-#ifdef HAVE_LIBDECOR_H
-#include <libdecor.h>
-#endif
-
 #include "../../input/common/wayland_common.h"
 
 #define WAYLAND_APP_ID "com.libretro.RetroArch"
 
-typedef struct toplevel_listener
-{
-#ifdef HAVE_LIBDECOR_H
-   struct libdecor_frame_interface libdecor_frame_interface;
-#endif
-   struct xdg_toplevel_listener xdg_toplevel_listener;
-} toplevel_listener_t;
-
 typedef struct shm_buffer
 {
    struct wl_buffer *wl_buffer;
@@ -38,23 +26,6 @@ typedef struct shm_buffer
    size_t data_size;
 } shm_buffer_t;
 
-void xdg_toplevel_handle_configure_common(gfx_ctx_wayland_data_t *wl, void *toplevel,
-      int32_t width, int32_t height, struct wl_array *states);
-
-void xdg_toplevel_handle_close(void *data,
-      struct xdg_toplevel *xdg_toplevel);
-
-#ifdef HAVE_LIBDECOR_H
-void libdecor_frame_handle_configure_common(struct libdecor_frame *frame,
-      struct libdecor_configuration *configuration, gfx_ctx_wayland_data_t *wl);
-
-void libdecor_frame_handle_close(struct libdecor_frame *frame,
-      void *data);
-
-void libdecor_frame_handle_commit(struct libdecor_frame *frame,
-      void *data);
-#endif
-
 void gfx_ctx_wl_get_video_size_common(void *data, unsigned *width,
       unsigned *height);
 
@@ -64,7 +35,7 @@ void gfx_ctx_wl_update_title_common(void *data);
 
 
 bool gfx_ctx_wl_init_common(
-      const toplevel_listener_t *toplevel_listener,
+      driver_configure_handler_t driver_configure_handler,
       gfx_ctx_wayland_data_t **wl);
 
 bool gfx_ctx_wl_set_video_mode_common_size(gfx_ctx_wayland_data_t *wl,
@@ -85,7 +56,3 @@ bool gfx_ctx_wl_has_focus(void *data);
 void gfx_ctx_wl_check_window_common(gfx_ctx_wayland_data_t *wl,
       void (*get_video_size)(void*, unsigned*, unsigned*), bool *quit,
       bool *resize, unsigned *width, unsigned *height);
-
-#ifdef HAVE_LIBDECOR_H
-extern const struct libdecor_interface libdecor_interface;
-#endif

gfx/drivers_context/wayland_ctx.c

@@ -55,7 +55,7 @@
 extern void gfx_ctx_wl_get_video_size_webos(void*, unsigned*, unsigned*);
 extern void gfx_ctx_wl_destroy_resources_webos(gfx_ctx_wayland_data_t*);
 extern void gfx_ctx_wl_update_title_webos(void*);
-extern bool gfx_ctx_wl_init_webos(const toplevel_listener_t*, gfx_ctx_wayland_data_t**);
+extern bool gfx_ctx_wl_init_webos(driver_configure_handler_t, gfx_ctx_wayland_data_t**);
 extern bool gfx_ctx_wl_set_video_mode_common_size_webos(gfx_ctx_wayland_data_t*, unsigned, unsigned, bool);
 extern bool gfx_ctx_wl_set_video_mode_common_fullscreen_webos(gfx_ctx_wayland_data_t*, bool);
 extern bool gfx_ctx_wl_suppress_screensaver_webos(void*, bool);
@@ -73,16 +73,12 @@ extern void gfx_ctx_wl_check_window_webos(gfx_ctx_wayland_data_t*, void (*)(void
 
 static enum gfx_ctx_api wl_api   = GFX_CTX_NONE;
 
-/* Shell surface callbacks. */
-static void xdg_toplevel_handle_configure(void *data,
-      struct xdg_toplevel *toplevel,
-      int32_t width, int32_t height, struct wl_array *states)
-{
-   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;
-   if (wl->ignore_configuration)
-      return;
-   xdg_toplevel_handle_configure_common(wl, toplevel, width, height, states);
 #ifdef HAVE_EGL
+/* Invoked from the common shell-surface configure handlers after the
+ * shared configure processing; resizes (or lazily creates) the
+ * wl_egl_window to the new buffer dimensions. */
+static void gfx_ctx_wl_egl_configure(gfx_ctx_wayland_data_t *wl)
+{
    if (wl->win)
       wl_egl_window_resize(wl->win,
             wl->buffer_width,
@@ -92,10 +88,8 @@ static void xdg_toplevel_handle_configure(void *data,
       wl->win = wl_egl_window_create(wl->surface,
             wl->buffer_width,
             wl->buffer_height);
-#endif
-
-   wl->configured = false;
 }
+#endif
 
 static void gfx_ctx_wl_destroy_resources(gfx_ctx_wayland_data_t *wl)
 {
@@ -139,49 +133,6 @@ static bool gfx_ctx_wl_set_resize(void *data, unsigned width, unsigned height)
    return true;
 }
 
-#ifdef HAVE_LIBDECOR_H
-static void
-libdecor_frame_handle_configure(struct libdecor_frame *frame,
-      struct libdecor_configuration *configuration, void *data)
-{
-   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;
-   if (wl->ignore_configuration)
-      return;
-   libdecor_frame_handle_configure_common(frame, configuration, wl);
-
-#ifdef HAVE_EGL
-   if (wl->win)
-      wl_egl_window_resize(wl->win,
-            wl->buffer_width,
-            wl->buffer_height,
-            0, 0);
-   else
-      wl->win     = wl_egl_window_create(
-            wl->surface,
-            wl->buffer_width,
-            wl->buffer_height);
-#endif
-
-   wl->configured = false;
-}
-#endif
-
-static const toplevel_listener_t toplevel_listener = {
-#ifdef HAVE_LIBDECOR_H
-   .libdecor_frame_interface = {
-     libdecor_frame_handle_configure,
-     libdecor_frame_handle_close,
-     libdecor_frame_handle_commit,
-   },
-#endif
-   .xdg_toplevel_listener = {
-      xdg_toplevel_handle_configure,
-      xdg_toplevel_handle_close,
-   },
-};
-
-static const toplevel_listener_t xdg_toplevel_listener = {0};
-
 #ifdef HAVE_EGL
 #define WL_EGL_ATTRIBS_BASE \
    EGL_SURFACE_TYPE,    EGL_WINDOW_BIT, \
@@ -280,7 +231,13 @@ static void *gfx_ctx_wl_init(void *data)
 {
    int i;
    gfx_ctx_wayland_data_t *wl = NULL;
-   if (!gfx_ctx_wl_init_common(&toplevel_listener, &wl))
+   if (!gfx_ctx_wl_init_common(
+#ifdef HAVE_EGL
+         gfx_ctx_wl_egl_configure,
+#else
+         NULL,
+#endif
+         &wl))
       goto error;
 #ifdef HAVE_EGL
    if (!gfx_ctx_wl_egl_init_context(wl))

gfx/drivers_context/wayland_vk_ctx.c

@@ -45,17 +45,6 @@
 #endif
 
 /* Shell surface callbacks. */
-static void xdg_toplevel_handle_configure(void *data,
-      struct xdg_toplevel *toplevel,
-      int32_t width, int32_t height, struct wl_array *states)
-{
-   gfx_ctx_wayland_data_t *wl = (gfx_ctx_wayland_data_t*)data;
-   if (wl->ignore_configuration)
-      return;
-   xdg_toplevel_handle_configure_common(wl, toplevel, width, height, states);
-   wl->configured = false;
-}
-
 static void gfx_ctx_wl_destroy_resources(gfx_ctx_wayland_data_t *wl)
 {
    if (!wl)
@@ -103,40 +92,12 @@ static bool gfx_ctx_wl_set_resize(void *data, unsigned width, unsigned height)
    return false;
 }
 
-#ifdef HAVE_LIBDECOR_H
-static void
-libdecor_frame_handle_configure(struct libdecor_frame *frame,
-      struct libdecor_configuration *configuration, void *data)
-{
-   gfx_ctx_wayland_data_t *wl   = (gfx_ctx_wayland_data_t*)data;
-   if (wl->ignore_configuration)
-      return;
-   libdecor_frame_handle_configure_common(frame, configuration, wl);
-
-   wl->configured = false;
-}
-#endif
-
-static const toplevel_listener_t toplevel_listener = {
-#ifdef HAVE_LIBDECOR_H
-   .libdecor_frame_interface = {
-     libdecor_frame_handle_configure,
-     libdecor_frame_handle_close,
-     libdecor_frame_handle_commit,
-   },
-#endif
-   .xdg_toplevel_listener = {
-      xdg_toplevel_handle_configure,
-      xdg_toplevel_handle_close,
-   },
-};
-
 static void *gfx_ctx_wl_init(void *data)
 {
    int i;
    gfx_ctx_wayland_data_t *wl = NULL;
 
-   if (!gfx_ctx_wl_init_common(&toplevel_listener, &wl))
+   if (!gfx_ctx_wl_init_common(NULL, &wl))
       goto error;
 
    if (!vulkan_context_init(&wl->vk, VULKAN_WSI_WAYLAND))

input/common/wayland_common.h

@@ -156,6 +156,12 @@ typedef struct data_offer_ctx
   enum wl_data_device_manager_dnd_action supported_actions;
 } data_offer_ctx;
 
+/* Per-backend hook invoked from the common shell-surface configure
+ * handlers, between the shared configure processing and the clearing
+ * of 'configured'.  EGL uses it to resize/create the wl_egl_window;
+ * Vulkan needs no additional action and passes NULL. */
+typedef void (*driver_configure_handler_t)(struct gfx_ctx_wayland_data *wl);
+
 typedef struct gfx_ctx_wayland_data
 {
 #ifdef HAVE_EGL
@@ -261,6 +267,7 @@ typedef struct gfx_ctx_wayland_data
    bool resize;
    bool configured;
    bool ignore_configuration;
+   driver_configure_handler_t driver_configure_handler;
    bool activated;
    bool reported_display_size;
    bool swap_complete;

input/common/wayland_common_webos.c

@@ -493,7 +493,7 @@ void gfx_ctx_wl_update_title_webos(void *data)
 }
 
 bool gfx_ctx_wl_init_webos(
-      const toplevel_listener_t *toplevel_listener, gfx_ctx_wayland_data_t **wwl)
+      driver_configure_handler_t driver_configure_handler, gfx_ctx_wayland_data_t **wwl)
 {
    int i;
    gfx_ctx_wayland_data_t *wl;