wayland: Cleanup timestamp handling

Better handle some very rare, but possible edge cases if the system has been running for many days.

Author: Kontrabant

src/video/wayland/SDL_waylandevents.c

@@ -179,7 +179,7 @@ static void Wayland_GetScaledMouseRect(SDL_Window *window, SDL_Rect *scaled_rect
     scaled_rect->h = (int)SDL_ceil(window->mouse_rect.h / window_data->pointer_scale.y);
 }
 
-static Uint64 Wayland_GetEventTimestamp(Uint64 nsTimestamp)
+static Uint64 Wayland_AdjustEventTimestampBase(Uint64 nsTimestamp)
 {
     static Uint64 timestamp_offset = 0;
     const Uint64 now = SDL_GetTicksNS();
@@ -197,16 +197,9 @@ static Uint64 Wayland_GetEventTimestamp(Uint64 nsTimestamp)
     return nsTimestamp;
 }
 
-static void input_timestamp_listener(void *data, struct zwp_input_timestamps_v1 *zwp_input_timestamps_v1,
-                                             uint32_t tv_sec_hi, uint32_t tv_sec_lo, uint32_t tv_nsec)
-{
-    *((Uint64 *)data) = ((((Uint64)tv_sec_hi << 32) | (Uint64)tv_sec_lo) * SDL_NS_PER_SECOND) + tv_nsec;
-}
-
-static const struct zwp_input_timestamps_v1_listener timestamp_listener = {
-    input_timestamp_listener
-};
-
+/* This should only be called with 32-bit millisecond timestamps received in Wayland events!
+ * No synthetic or high-res timestamps, as they can corrupt the rollover offset!
+ */
 static Uint64 Wayland_EventTimestampMSToNS(Uint32 wl_timestamp_ms)
 {
     static Uint64 timestamp_offset = 0;
@@ -222,38 +215,38 @@ static Uint64 Wayland_EventTimestampMSToNS(Uint32 wl_timestamp_ms)
     return SDL_MS_TO_NS(wl_timestamp_ms) + timestamp_offset;
 }
 
-static Uint64 Wayland_GetKeyboardTimestamp(SDL_WaylandSeat *seat, Uint32 wl_timestamp_ms)
-{
-    if (wl_timestamp_ms) {
-        return Wayland_GetEventTimestamp(seat->keyboard.highres_timestamp_ns ? seat->keyboard.highres_timestamp_ns : Wayland_EventTimestampMSToNS(wl_timestamp_ms));
-    }
-
-    return 0;
-}
+/* Even if high-res timestamps are available, the millisecond timestamps are still processed
+ * to accumulate the rollover offset if needed later.
+ */
 
 static Uint64 Wayland_GetKeyboardTimestampRaw(SDL_WaylandSeat *seat, Uint32 wl_timestamp_ms)
 {
-    return seat->keyboard.highres_timestamp_ns ? seat->keyboard.highres_timestamp_ns : Wayland_EventTimestampMSToNS(wl_timestamp_ms);
+    const Uint64 adjustedTimestampMS = Wayland_EventTimestampMSToNS(wl_timestamp_ms);
+    return seat->keyboard.timestamps ? seat->keyboard.highres_timestamp_ns : adjustedTimestampMS;
 }
 
 static Uint64 Wayland_GetPointerTimestamp(SDL_WaylandSeat *seat, Uint32 wl_timestamp_ms)
 {
-    if (wl_timestamp_ms) {
-        return Wayland_GetEventTimestamp(seat->pointer.highres_timestamp_ns ? seat->pointer.highres_timestamp_ns : Wayland_EventTimestampMSToNS(wl_timestamp_ms));
-    }
-
-    return 0;
+    const Uint64 adjustedTimestampMS = Wayland_EventTimestampMSToNS(wl_timestamp_ms);
+    return Wayland_AdjustEventTimestampBase(seat->pointer.timestamps ? seat->pointer.highres_timestamp_ns : adjustedTimestampMS);
 }
 
 Uint64 Wayland_GetTouchTimestamp(SDL_WaylandSeat *seat, Uint32 wl_timestamp_ms)
 {
-    if (wl_timestamp_ms) {
-        return Wayland_GetEventTimestamp(seat->touch.highres_timestamp_ns ? seat->touch.highres_timestamp_ns : Wayland_EventTimestampMSToNS(wl_timestamp_ms));
-    }
+    const Uint64 adjustedTimestampMS = Wayland_EventTimestampMSToNS(wl_timestamp_ms);
+    return Wayland_AdjustEventTimestampBase(seat->touch.timestamps ? seat->touch.highres_timestamp_ns : adjustedTimestampMS);
+}
 
-    return 0;
+static void input_timestamp_listener(void *data, struct zwp_input_timestamps_v1 *zwp_input_timestamps_v1,
+                                             uint32_t tv_sec_hi, uint32_t tv_sec_lo, uint32_t tv_nsec)
+{
+    *((Uint64 *)data) = ((((Uint64)tv_sec_hi << 32) | (Uint64)tv_sec_lo) * SDL_NS_PER_SECOND) + tv_nsec;
 }
 
+static const struct zwp_input_timestamps_v1_listener timestamp_listener = {
+    input_timestamp_listener
+};
+
 static void Wayland_SeatRegisterInputTimestampListeners(SDL_WaylandSeat *seat)
 {
     if (seat->display->input_timestamps_manager) {
@@ -308,7 +301,7 @@ static bool keyboard_repeat_handle(SDL_WaylandKeyboardRepeat *repeat_info, Uint6
     while (elapsed >= repeat_info->next_repeat_ns) {
         if (repeat_info->scancode != SDL_SCANCODE_UNKNOWN) {
             const Uint64 timestamp = repeat_info->wl_press_time_ns + repeat_info->next_repeat_ns;
-            SDL_SendKeyboardKeyIgnoreModifiers(Wayland_GetEventTimestamp(timestamp), repeat_info->keyboard_id, repeat_info->key, repeat_info->scancode, true);
+            SDL_SendKeyboardKeyIgnoreModifiers(Wayland_AdjustEventTimestampBase(timestamp), repeat_info->keyboard_id, repeat_info->key, repeat_info->scancode, true);
         }
         if (repeat_info->text[0]) {
             SDL_SendKeyboardText(repeat_info->text);
@@ -574,17 +567,15 @@ void Wayland_PumpEvents(SDL_VideoDevice *_this)
     }
 }
 
-static void pointer_handle_motion(void *data, struct wl_pointer *pointer,
-                                  uint32_t time, wl_fixed_t sx_w, wl_fixed_t sy_w)
+static void pointer_handle_motion_common(SDL_WaylandSeat *seat, Uint64 nsTimestamp, wl_fixed_t sx_w, wl_fixed_t sy_w)
 {
-    SDL_WaylandSeat *seat = data;
     SDL_WindowData *window_data = seat->pointer.focus;
     SDL_Window *window = window_data ? window_data->sdlwindow : NULL;
 
     if (window_data) {
         const float sx = (float)(wl_fixed_to_double(sx_w) * window_data->pointer_scale.x);
         const float sy = (float)(wl_fixed_to_double(sy_w) * window_data->pointer_scale.y);
-        SDL_SendMouseMotion(Wayland_GetPointerTimestamp(seat, time), window_data->sdlwindow, seat->pointer.sdl_id, false, sx, sy);
+        SDL_SendMouseMotion(nsTimestamp, window_data->sdlwindow, seat->pointer.sdl_id, false, sx, sy);
 
         seat->pointer.last_motion.x = (int)SDL_floorf(sx);
         seat->pointer.last_motion.y = (int)SDL_floorf(sy);
@@ -678,6 +669,13 @@ static void pointer_handle_motion(void *data, struct wl_pointer *pointer,
     }
 }
 
+static void pointer_handle_motion(void *data, struct wl_pointer *pointer,
+                                  uint32_t time, wl_fixed_t sx_w, wl_fixed_t sy_w)
+{
+    SDL_WaylandSeat *seat = (SDL_WaylandSeat *)data;
+    pointer_handle_motion_common(seat, Wayland_GetPointerTimestamp(seat, time), sx_w, sy_w);
+}
+
 static void pointer_handle_enter(void *data, struct wl_pointer *pointer,
                                  uint32_t serial, struct wl_surface *surface,
                                  wl_fixed_t sx_w, wl_fixed_t sy_w)
@@ -706,7 +704,7 @@ static void pointer_handle_enter(void *data, struct wl_pointer *pointer,
      * FIXME: This causes a movement event with an anomalous timestamp when
      *        the cursor enters the window.
      */
-    pointer_handle_motion(data, pointer, 0, sx_w, sy_w);
+    pointer_handle_motion_common(seat, 0, sx_w, sy_w);
 
     // Update the pointer grab state.
     Wayland_SeatUpdatePointerGrab(seat);
@@ -845,11 +843,10 @@ static bool Wayland_ProcessHitTest(SDL_WaylandSeat *seat, Uint32 serial)
 }
 
 static void pointer_handle_button_common(SDL_WaylandSeat *seat, uint32_t serial,
-                                         uint32_t time, uint32_t button, uint32_t state_w)
+                                         Uint64 nsTimestamp, uint32_t button, uint32_t state_w)
 {
     SDL_WindowData *window = seat->pointer.focus;
     enum wl_pointer_button_state state = state_w;
-    Uint64 timestamp = Wayland_GetPointerTimestamp(seat, time);
     Uint8 sdl_button;
     const bool down = (state != 0);
 
@@ -913,7 +910,7 @@ static void pointer_handle_button_common(SDL_WaylandSeat *seat, uint32_t serial,
         }
 
         if (!ignore_click) {
-            SDL_SendMouseButton(timestamp, window->sdlwindow, seat->pointer.sdl_id, sdl_button, down);
+            SDL_SendMouseButton(nsTimestamp, window->sdlwindow, seat->pointer.sdl_id, sdl_button, down);
         }
     }
 }
@@ -922,15 +919,13 @@ static void pointer_handle_button(void *data, struct wl_pointer *pointer, uint32
                                   uint32_t time, uint32_t button, uint32_t state_w)
 {
     SDL_WaylandSeat *seat = data;
-
-    pointer_handle_button_common(seat, serial, time, button, state_w);
+    pointer_handle_button_common(seat, serial, Wayland_GetPointerTimestamp(seat, time), button, state_w);
 }
 
 static void pointer_handle_axis_common_v1(SDL_WaylandSeat *seat,
-                                          uint32_t time, uint32_t axis, wl_fixed_t value)
+                                          Uint64 nsTimestamp, uint32_t axis, wl_fixed_t value)
 {
     SDL_WindowData *window = seat->pointer.focus;
-    const Uint64 timestamp = Wayland_GetPointerTimestamp(seat, time);
     const enum wl_pointer_axis a = axis;
 
     if (seat->pointer.focus) {
@@ -952,7 +947,7 @@ static void pointer_handle_axis_common_v1(SDL_WaylandSeat *seat,
         x /= WAYLAND_WHEEL_AXIS_UNIT;
         y /= WAYLAND_WHEEL_AXIS_UNIT;
 
-        SDL_SendMouseWheel(timestamp, window->sdlwindow, seat->pointer.sdl_id, x, y, SDL_MOUSEWHEEL_NORMAL);
+        SDL_SendMouseWheel(nsTimestamp, window->sdlwindow, seat->pointer.sdl_id, x, y, SDL_MOUSEWHEEL_NORMAL);
     }
 }
 
@@ -1033,12 +1028,13 @@ static void pointer_handle_axis(void *data, struct wl_pointer *pointer,
                                 uint32_t time, uint32_t axis, wl_fixed_t value)
 {
     SDL_WaylandSeat *seat = data;
+    const Uint64 nsTimestamp = Wayland_GetPointerTimestamp(seat, time);
 
     if (wl_seat_get_version(seat->wl_seat) >= WL_POINTER_FRAME_SINCE_VERSION) {
-        seat->pointer.current_axis_info.timestamp_ns = Wayland_GetPointerTimestamp(seat, time);
+        seat->pointer.current_axis_info.timestamp_ns = nsTimestamp;
         pointer_handle_axis_common(seat, AXIS_EVENT_CONTINUOUS, axis, value);
     } else {
-        pointer_handle_axis_common_v1(seat, time, axis, value);
+        pointer_handle_axis_common_v1(seat, nsTimestamp, axis, value);
     }
 }
 
@@ -1166,7 +1162,7 @@ static void relative_pointer_handle_relative_motion(void *data,
             SDL_Mouse *mouse = SDL_GetMouse();
 
             // Relative pointer event times are in microsecond granularity.
-            const Uint64 timestamp = Wayland_GetEventTimestamp(SDL_US_TO_NS(((Uint64)time_hi << 32) | (Uint64)time_lo));
+            const Uint64 timestamp = Wayland_AdjustEventTimestampBase(SDL_US_TO_NS(((Uint64)time_hi << 32) | (Uint64)time_lo));
 
             double dx;
             double dy;
@@ -2022,7 +2018,7 @@ static void keyboard_handle_key(void *data, struct wl_keyboard *keyboard,
 
     const SDL_Scancode scancode = Wayland_GetScancodeForKey(seat, key);
     Wayland_HandleModifierKeys(seat, scancode, state == WL_KEYBOARD_KEY_STATE_PRESSED);
-    Uint64 timestamp = Wayland_GetKeyboardTimestamp(seat, time);
+    Uint64 timestamp = Wayland_AdjustEventTimestampBase(timestamp_raw_ns);
 
     SDL_SendKeyboardKeyIgnoreModifiers(timestamp, seat->keyboard.sdl_id, key, scancode, state == WL_KEYBOARD_KEY_STATE_PRESSED);
 
@@ -3243,7 +3239,7 @@ static void tablet_tool_handle_frame(void *data, struct zwp_tablet_tool_v2 *tool
         return;  // Not a pen we report on.
     }
 
-    const Uint64 timestamp = Wayland_GetEventTimestamp(Wayland_EventTimestampMSToNS(time));
+    const Uint64 timestamp = Wayland_AdjustEventTimestampBase(Wayland_EventTimestampMSToNS(time));
     const SDL_PenID instance_id = sdltool->instance_id;
     SDL_Window *window = sdltool->tool_focus;