Merge branch 'backend-selection' into main

- Implement runtime backend selection (Wayland, X11, Cocoa)
- Add native X11 backend with clipboard, keyboard, mouse, and placement
- Integrate multi-backend integration tests running under Weston and Xwayland
- Retain zero-hole struct packing, branchless ALU/LUT primitives, and paced event loop

1 files changed, 58 insertions, 56 deletions

diff --git a/src/wayland/internal.h b/src/wayland/internal.h
index 79fd88d..cba5096 100644
--- a/src/wayland/internal.h
+++ b/src/wayland/internal.h
@@ -3,7 +3,7 @@
 
 #define _GNU_SOURCE
 
-#include "yasl/yasl.h"
+#include "api.h"
 #include "yasl/timing.h"
 #include "clipboard.h"
 
@@ -41,13 +41,13 @@
 
 #define NBUF 3
 
-struct yasl_surface;
+struct wayland_surface;
 struct tablet_tool;
 struct tablet_device;
 struct tablet_pad;
 
 struct buffer {
-    struct yasl_surface *owner;
+    struct wayland_surface *owner;
     struct wl_shm_pool *pool;
     struct wl_buffer *proxy;
     uint32_t *pixels;
@@ -58,7 +58,7 @@ struct buffer {
 };
 
 struct wl_conn_output {
-    struct yasl_display *conn;
+    struct wayland_display *conn;
     struct wl_output *proxy;
     struct wl_conn_output *next;
     uint64_t mask;
@@ -68,7 +68,7 @@ struct wl_conn_output {
 };
 
 struct pending_press {
-    struct yasl_surface *surface;
+    struct wayland_surface *surface;
     struct yasl_vector2i pos;
     int button;
     bool release;
@@ -111,7 +111,7 @@ struct conn_drag {
 #define SEAT_TOUCH_POINTS 10
 
 struct touch_point {
-    struct yasl_surface *surface;
+    struct wayland_surface *surface;
     double x, y;
     int32_t id;
     bool active;
@@ -122,7 +122,7 @@ struct touch_point {
 
 struct seat {
     /* 8-byte aligned pointers and 64-bit values */
-    struct yasl_display *conn;
+    struct wayland_display *conn;
     struct seat *next;
     struct wl_seat *proxy;
     struct wl_keyboard *keyboard;
@@ -140,13 +140,13 @@ struct seat {
     struct xkb_keymap *xkb_keymap;
     struct xkb_state *xkb_state;
     uint64_t repeat_started_ns;
-    struct yasl_surface *pointer_focus;
-    struct yasl_surface *keyboard_focus;
-    struct yasl_surface *tablet_focus;
-    struct yasl_surface *ime_focus;
-    struct yasl_surface *focus_leaving;
-    struct yasl_surface *press_surface;
-    struct yasl_surface *ptr_left;
+    struct wayland_surface *pointer_focus;
+    struct wayland_surface *keyboard_focus;
+    struct wayland_surface *tablet_focus;
+    struct wayland_surface *ime_focus;
+    struct wayland_surface *focus_leaving;
+    struct wayland_surface *press_surface;
+    struct wayland_surface *ptr_left;
     struct tablet_tool *tool;
     struct touch_point *touch_primary;
     uint64_t pointer_buttons;
@@ -223,7 +223,8 @@ static inline void input_queue_clear(struct input_queue *q)
     q->head = q->tail = q->count = 0;
 }
 
-struct yasl_display {
+struct wayland_display {
+    struct yasl_display base;
     /* 8-byte pointers & 64-bit masks */
     struct wl_display *wl;
     struct wl_registry *registry;
@@ -255,9 +256,9 @@ struct yasl_display {
     char *app_id;
     struct xdg_toplevel_drag_manager_v1 *toplevel_drag_mgr;
     struct conn_drag drag;
-    struct yasl_surface *surfaces;
-    struct yasl_surface *paste_target;
-    struct yasl_surface *dead;
+    struct wayland_surface *surfaces;
+    struct wayland_surface *paste_target;
+    struct wayland_surface *dead;
 
     /* 4-byte integers */
     int cursor_size;
@@ -273,12 +274,13 @@ struct yasl_display {
     bool lost;
 };
 
-struct yasl_surface {
+struct wayland_surface {
+    struct yasl_surface base;
     /* 8-byte pointers & 64-bit values */
-    struct yasl_display *conn;
-    struct yasl_surface *conn_next;
-    struct yasl_surface *dead_next;
-    struct yasl_surface *parent;
+    struct wayland_display *conn;
+    struct wayland_surface *conn_next;
+    struct wayland_surface *dead_next;
+    struct wayland_surface *parent;
     struct wl_surface *surface;
     struct xdg_surface *xdg_surface;
     struct xdg_toplevel *toplevel;
@@ -348,12 +350,12 @@ bool  yasl_utf8_validate(const char *str, size_t len);
 
 int  device_px(int logical, uint32_t scale_120);
 bool buffer_size(int width, int height, size_t *bytes);
-int  buffer_reserve(struct yasl_surface *w, struct buffer *b, size_t needed);
+int  buffer_reserve(struct wayland_surface *w, struct buffer *b, size_t needed);
 void buffer_destroy(struct buffer *b);
 int  buffer_pick_free_index(const struct buffer *bufs, int cur);
-int  buffer_prepare(struct yasl_surface *w, struct buffer *b, int width, int height,
+int  buffer_prepare(struct wayland_surface *w, struct buffer *b, int width, int height,
                     const struct wl_buffer_listener *listener);
-int  apply_pending_geometry(struct yasl_surface *w);
+int  apply_pending_geometry(struct wayland_surface *w);
 int  logical_px_ceil(int device, uint32_t scale_120);
 
 static inline void wl_damage_list(struct wl_surface *s, const struct yasl_damage_list *d)
@@ -368,8 +370,8 @@ static inline void wl_damage_list(struct wl_surface *s, const struct yasl_damage
                                  d->rects[i].width, d->rects[i].height);
 }
 
-void surface_update_opaque_region(struct yasl_surface *w);
-int  surface_init_scaling(struct yasl_surface *w);
+void surface_update_opaque_region(struct wayland_surface *w);
+int  surface_init_scaling(struct wayland_surface *w);
 
 static inline bool surface_gets_preferred_scale(struct wl_surface *s)
 {
@@ -377,65 +379,65 @@ static inline bool surface_gets_preferred_scale(struct wl_surface *s)
            WL_SURFACE_PREFERRED_BUFFER_SCALE_SINCE_VERSION;
 }
 
-uint64_t conn_output_mask(const struct yasl_display *c, const struct wl_output *proxy);
-uint32_t conn_output_scale_120(const struct yasl_display *c, uint64_t outputs);
-void     conn_destroy_outputs(struct yasl_display *c);
-void     surface_follow_outputs(struct yasl_surface *w);
-uint64_t conn_pres_to_mono(const struct yasl_display *c, uint64_t ns);
-uint64_t conn_mono_to_pres(const struct yasl_display *c, uint64_t ns);
-void surface_draw_frame(struct yasl_surface *w);
-void surface_fail(struct yasl_surface *w);
-void display_enter(struct yasl_display *c);
-void display_leave(struct yasl_display *c);
+uint64_t conn_output_mask(const struct wayland_display *c, const struct wl_output *proxy);
+uint32_t conn_output_scale_120(const struct wayland_display *c, uint64_t outputs);
+void     conn_destroy_outputs(struct wayland_display *c);
+void     surface_follow_outputs(struct wayland_surface *w);
+uint64_t conn_pres_to_mono(const struct wayland_display *c, uint64_t ns);
+uint64_t conn_mono_to_pres(const struct wayland_display *c, uint64_t ns);
+void surface_draw_frame(struct wayland_surface *w);
+void surface_fail(struct wayland_surface *w);
+void display_enter(struct wayland_display *c);
+void display_leave(struct wayland_display *c);
 
-struct yasl_surface *conn_surface_for(struct yasl_display *c, struct wl_surface *s);
+struct wayland_surface *conn_surface_for(struct wayland_display *c, struct wl_surface *s);
 
-static inline struct yasl_surface *surface_root(struct yasl_surface *w)
+static inline struct wayland_surface *surface_root(struct wayland_surface *w)
 {
     while (w && w->parent)
         w = w->parent;
     return w;
 }
 
-void conn_drag_end(struct yasl_display *c);
-void conn_drop_target(struct yasl_display *c, enum yasl_drop_event ev,
+void conn_drag_end(struct wayland_display *c);
+void conn_drop_target(struct wayland_display *c, enum yasl_drop_event ev,
                       struct wl_surface *on, double x, double y);
-void conn_drag_target(struct yasl_display *c, enum yasl_drag_event ev,
+void conn_drag_target(struct wayland_display *c, enum yasl_drag_event ev,
                       struct wl_surface *on, double x, double y);
 
-void seat_bind(struct yasl_display *c, struct wl_registry *registry,
+void seat_bind(struct wayland_display *c, struct wl_registry *registry,
                uint32_t name, uint32_t version);
-bool seat_remove(struct yasl_display *c, uint32_t name);
+bool seat_remove(struct wayland_display *c, uint32_t name);
 void seat_destroy(struct seat *s);
-struct seat *conn_active_seat(const struct yasl_display *c);
+struct seat *conn_active_seat(const struct wayland_display *c);
 void seat_note_input(struct seat *s, uint32_t serial);
-void seat_forget_surface(struct seat *s, struct yasl_surface *w);
+void seat_forget_surface(struct seat *s, struct wayland_surface *w);
 void seat_clipboard_ensure(struct seat *s);
-int  display_input_init(struct yasl_display *c);
+int  display_input_init(struct wayland_display *c);
 extern const struct wl_seat_listener seat_listener;
 
 void keyboard_repeat_stop(struct seat *s);
 void keyboard_repeat_sync(struct seat *s);
 int  keyboard_repeat_init(struct seat *s);
-void keyboard_settle_focus(struct yasl_display *c);
-bool conn_keyboard_on(const struct yasl_display *c, const struct yasl_surface *w,
+void keyboard_settle_focus(struct wayland_display *c);
+bool conn_keyboard_on(const struct wayland_display *c, const struct wayland_surface *w,
                       const struct seat *except);
 extern const struct wl_keyboard_listener keyboard_listener;
 int  seat_modifiers(const struct seat *s);
 
-void surface_init_cursor(struct yasl_display *c);
+void surface_init_cursor(struct wayland_display *c);
 void seat_destroy_tablet(struct seat *s);
 void seat_pointer_reset(struct seat *s);
 
 extern const struct zwp_text_input_v3_listener text_input_listener;
-void ime_reset(struct yasl_surface *w);
-void ime_send_caret(struct yasl_surface *w);
+void ime_reset(struct wayland_surface *w);
+void ime_send_caret(struct wayland_surface *w);
 
-int  surface_init_shell(struct yasl_surface *w, const char *title);
+int  surface_init_shell(struct wayland_surface *w, const char *title);
 extern const struct xdg_surface_listener shell_surface_listener;
 extern const struct wl_registry_listener registry_listener;
 
-void surface_feedback_destroy(struct yasl_surface *w);
-void surface_request_presentation_feedback(struct yasl_surface *w);
+void surface_feedback_destroy(struct wayland_surface *w);
+void surface_request_presentation_feedback(struct wayland_surface *w);
 
 #endif