Fix present/link sync regressions and harden framebuffer integrity

examples/zr_example_common.h

@@ -31,7 +31,9 @@ static inline uint32_t zr_ex_le32_read(const uint8_t* p) {
 
 /* --- Alignment --- */
 
-static inline uint32_t zr_ex_align4_u32(uint32_t x) { return (x + 3u) & ~3u; }
+static inline uint32_t zr_ex_align4_u32(uint32_t x) {
+  return (x + 3u) & ~3u;
+}
 
 /* --- Color --- */
 
@@ -40,4 +42,3 @@ static inline uint32_t zr_ex_rgb_u32(uint8_t r, uint8_t g, uint8_t b) {
 }
 
 #endif /* ZR_EXAMPLE_COMMON_H_INCLUDED */
-

include/zr/zr_caps.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_CAPS_H_INCLUDED
 #define ZR_ZR_CAPS_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_result.h"
 
 #include <stdint.h>
@@ -46,4 +50,8 @@ zr_limits_t zr_limits_default(void);
 /* Validate limit values and relationships. */
 zr_result_t zr_limits_validate(const zr_limits_t* limits);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_CAPS_H_INCLUDED */

include/zr/zr_config.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_CONFIG_H_INCLUDED
 #define ZR_ZR_CONFIG_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_caps.h"
 #include "zr/zr_platform_types.h"
 #include "zr/zr_result.h"
@@ -92,4 +96,8 @@ zr_result_t zr_engine_config_validate(const zr_engine_config_t* cfg);
 /* Validate runtime config for engine_set_config. */
 zr_result_t zr_engine_runtime_config_validate(const zr_engine_runtime_config_t* cfg);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_CONFIG_H_INCLUDED */

include/zr/zr_debug.h

@@ -14,6 +14,10 @@
 #ifndef ZR_ZR_DEBUG_H_INCLUDED
 #define ZR_ZR_DEBUG_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_result.h"
 
 #include <stdint.h>
@@ -220,4 +224,8 @@ typedef struct zr_debug_stats_t {
 */
 zr_debug_config_t zr_debug_config_default(void);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_DEBUG_H_INCLUDED */

include/zr/zr_drawlist.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_DRAWLIST_H_INCLUDED
 #define ZR_ZR_DRAWLIST_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <stdint.h>
 
 /* ABI-facing types (little-endian on-wire). */
@@ -260,4 +264,8 @@ typedef struct zr_dl_cmd_free_resource_t {
   uint32_t id;
 } zr_dl_cmd_free_resource_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_DRAWLIST_H_INCLUDED */

include/zr/zr_engine.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_ENGINE_H_INCLUDED
 #define ZR_ZR_ENGINE_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_config.h"
 #include "zr/zr_debug.h"
 #include "zr/zr_metrics.h"
@@ -199,4 +203,8 @@ int32_t engine_debug_export(zr_engine_t* e, uint8_t* out_buf, size_t out_cap);
 /* Clear trace records while keeping tracing enabled. */
 void engine_debug_reset(zr_engine_t* e);
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_ENGINE_H_INCLUDED */

include/zr/zr_event.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_EVENT_H_INCLUDED
 #define ZR_ZR_EVENT_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_version.h"
 
 #include <stddef.h>
@@ -188,4 +192,8 @@ typedef struct zr_ev_user_t {
   uint32_t reserved1;
 } zr_ev_user_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_EVENT_H_INCLUDED */

include/zr/zr_metrics.h

@@ -9,6 +9,10 @@
 #ifndef ZR_ZR_METRICS_H_INCLUDED
 #define ZR_ZR_METRICS_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <stdint.h>
 
 /*
@@ -64,8 +68,12 @@ typedef struct zr_metrics_t {
   /* --- Damage summary (last frame) --- */
   uint32_t damage_rects_last_frame;
   uint32_t damage_cells_last_frame;
-  uint8_t  damage_full_frame;
-  uint8_t  _pad2[3];
+  uint8_t damage_full_frame;
+  uint8_t _pad2[3];
 } zr_metrics_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_METRICS_H_INCLUDED */

include/zr/zr_platform_types.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_PLATFORM_TYPES_H_INCLUDED
 #define ZR_ZR_PLATFORM_TYPES_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include <stdint.h>
 
 /*
@@ -69,4 +73,8 @@ typedef struct plat_config_t {
   uint8_t _pad[3];
 } plat_config_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_PLATFORM_TYPES_H_INCLUDED */

include/zr/zr_result.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_RESULT_H_INCLUDED
 #define ZR_ZR_RESULT_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 typedef int zr_result_t;
 
 /* Success. */
@@ -25,4 +29,8 @@ typedef int zr_result_t;
 #define ZR_ERR_FORMAT ((zr_result_t) - 5)
 #define ZR_ERR_PLATFORM ((zr_result_t) - 6)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_RESULT_H_INCLUDED */

include/zr/zr_terminal_caps.h

@@ -9,6 +9,10 @@
 #ifndef ZR_ZR_TERMINAL_CAPS_H_INCLUDED
 #define ZR_ZR_TERMINAL_CAPS_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 #include "zr/zr_platform_types.h"
 
 #include <stdint.h>
@@ -157,4 +161,8 @@ typedef struct zr_terminal_caps_t {
   zr_terminal_cap_flags_t cap_suppress_flags;
 } zr_terminal_caps_t;
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_TERMINAL_CAPS_H_INCLUDED */

include/zr/zr_version.h

@@ -8,6 +8,10 @@
 #ifndef ZR_ZR_VERSION_H_INCLUDED
 #define ZR_ZR_VERSION_H_INCLUDED
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /*
   NOTE: These version pins are part of the determinism contract. They must not
   be overridden by downstream builds.
@@ -35,4 +39,8 @@
 /* Packed event batch binary format versions. */
 #define ZR_EVENT_BATCH_VERSION_V1 (1u)
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZR_ZR_VERSION_H_INCLUDED */

src/core/zr_cursor.h

@@ -12,9 +12,9 @@
 #include <stdint.h>
 
 typedef uint8_t zr_cursor_shape_t;
-#define ZR_CURSOR_SHAPE_BLOCK     ((zr_cursor_shape_t)0u)
+#define ZR_CURSOR_SHAPE_BLOCK ((zr_cursor_shape_t)0u)
 #define ZR_CURSOR_SHAPE_UNDERLINE ((zr_cursor_shape_t)1u)
-#define ZR_CURSOR_SHAPE_BAR       ((zr_cursor_shape_t)2u)
+#define ZR_CURSOR_SHAPE_BAR ((zr_cursor_shape_t)2u)
 
 /*
   zr_cursor_state_t:
@@ -32,4 +32,3 @@ typedef struct zr_cursor_state_t {
 } zr_cursor_state_t;
 
 #endif /* ZR_CORE_ZR_CURSOR_H_INCLUDED */
-

src/core/zr_damage.c

@@ -46,6 +46,7 @@ static void zr_damage_mark_full(zr_damage_t* d) {
   d->rects[0].y0 = 0u;
   d->rects[0].x1 = d->cols - 1u;
   d->rects[0].y1 = d->rows - 1u;
+  d->rects[0]._link = UINT32_MAX;
   d->rect_count = 1u;
 }
 
@@ -97,6 +98,7 @@ void zr_damage_add_span(zr_damage_t* d, uint32_t y, uint32_t x0, uint32_t x1) {
   r->y0 = y;
   r->x1 = x1;
   r->y1 = y;
+  r->_link = UINT32_MAX;
 }
 
 uint32_t zr_damage_cells(const zr_damage_t* d) {

src/core/zr_damage.h

@@ -16,22 +16,30 @@ typedef struct zr_damage_rect_t {
   uint32_t y0;
   uint32_t x1;
   uint32_t y1;
+  /*
+    Scratch link field for allocation-free damage coalescing.
+
+    Why: The diff renderer's indexed damage-walk needs per-rectangle "next"
+    pointers but must not clobber the rectangle coordinates because the engine
+    can reuse the computed rectangles after diff emission (e.g. for fb_prev
+    resync on partial presents).
+  */
+  uint32_t _link;
 } zr_damage_rect_t;
 
 typedef struct zr_damage_t {
   zr_damage_rect_t* rects;
-  uint32_t          rect_cap;
-  uint32_t          rect_count;
-  uint32_t          cols;
-  uint32_t          rows;
-  uint8_t           full_frame;
-  uint8_t           _pad0[3];
+  uint32_t rect_cap;
+  uint32_t rect_count;
+  uint32_t cols;
+  uint32_t rows;
+  uint8_t full_frame;
+  uint8_t _pad0[3];
 } zr_damage_t;
 
-void     zr_damage_begin_frame(zr_damage_t* d, zr_damage_rect_t* storage, uint32_t storage_cap, uint32_t cols,
-                               uint32_t rows);
-void     zr_damage_add_span(zr_damage_t* d, uint32_t y, uint32_t x0, uint32_t x1);
+void zr_damage_begin_frame(zr_damage_t* d, zr_damage_rect_t* storage, uint32_t storage_cap, uint32_t cols,
+                           uint32_t rows);
+void zr_damage_add_span(zr_damage_t* d, uint32_t y, uint32_t x0, uint32_t x1);
 uint32_t zr_damage_cells(const zr_damage_t* d);
 
 #endif /* ZR_CORE_ZR_DAMAGE_H_INCLUDED */
-