Improve snapshop saving and loading

SchwertUndMagieOnPebbleCompanionApp/app/src/main/jni/vice_jni.c

@@ -51,6 +51,12 @@ static volatile int    g_pending_reset      = 0;
 static char            g_pending_save_state[512];
 static char            g_pending_load_state[512];
 
+/* Path of the disk image most recently placed in drive 8.
+ * After machine_read_snapshot the virtual device loses track of the attached
+ * D64 and falls back to host-filesystem mode.  Re-attaching this path
+ * immediately after a successful snapshot load restores D64 access. */
+static char g_current_disk_path[512] = {0};
+
 /* =========================================================================
  * VICE integration (compiled only when libvice.a is linked in)
  * ========================================================================= */
@@ -392,11 +398,14 @@ void video_canvas_refresh(video_canvas_t *canvas,
     if (g_pending_disk[0]   != '\0') { strncpy(autostart_path, g_pending_disk,   sizeof(autostart_path)-1); g_pending_disk[0]   = '\0'; }
     if (g_pending_attach[0] != '\0') { strncpy(attach_path,    g_pending_attach, sizeof(attach_path)-1);    g_pending_attach[0] = '\0'; }
     pthread_mutex_unlock(&g_pending_lock);
-    if (autostart_path[0] != '\0')
+    if (autostart_path[0] != '\0') {
         autostart_disk(8, 0, autostart_path, NULL, 0, AUTOSTART_MODE_RUN);
+        strncpy(g_current_disk_path, autostart_path, sizeof(g_current_disk_path) - 1);
+    }
     if (attach_path[0] != '\0') {
         int r = file_system_attach_disk(8, 0, attach_path);
         if (r == 0) {
+            strncpy(g_current_disk_path, attach_path, sizeof(g_current_disk_path) - 1);
             g_load_frames   = 0;   /* clear old cooldown; new autostart will set a fresh one */
             g_attach_frames = 75;  /* show LED for ~1.5 s immediately after hot-swap */
         }
@@ -416,12 +425,19 @@ void video_canvas_refresh(video_canvas_t *canvas,
     }
     pthread_mutex_unlock(&g_pending_lock);
     if (save_state_path[0] != '\0') {
-        int r = machine_write_snapshot(save_state_path, 0, 1, 1);
+        /* save_roms=0, save_disks=0: disk management is handled by our UI;
+         * skipping the drive module avoids path-resolution failures on restore. */
+        int r = machine_write_snapshot(save_state_path, 0, 0, 0);
         LOGI("machine_write_snapshot → %d", r);
     }
     if (load_state_path[0] != '\0') {
         int r = machine_read_snapshot(load_state_path, 0);
         LOGI("machine_read_snapshot → %d", r);
+        /* After snapshot restore the virtual device loses its D64 attachment
+         * and falls back to host-filesystem mode.  Re-attach the same disk so
+         * the C64 program can continue reading from the image it expected. */
+        if (r == 0 && g_current_disk_path[0] != '\0')
+            file_system_attach_disk(8, 0, g_current_disk_path);
     }
 
     /* Drive LED.