Navigation code reads the ships into a ship list, and writes them back
when it changes them, e.g. when a ship stops. If a ship changes in
the ship file while it is in such a ship list, the copy in the ship
list becomes stale, and must not be used.
To that end, do_unit_move() calls shp_nav() after prompting for path
or destination. shp_nav() re-reads all the ships. Unfortunately, it
still writes back stale copies in certain circumstances. Known ways
to trigger such writes:
* Deity sets a sail path
* Ship's crew gone, e.g. killed by shell fire
* Sector no longer navigable, e.g. harbor shelled down, or bridge
built
Writing a stale copy wipes out the updates that made the copy stale,
and triggers a seqno mismatch oops. For instance, ship damage that
kills all crew while the ship is being navigated gets wiped out.
struct emp_qelem *qp;
struct emp_qelem *next;
struct ulist *mlp;
struct emp_qelem *qp;
struct emp_qelem *next;
struct ulist *mlp;
coord allx;
coord ally;
int first = 1;
coord allx;
coord ally;
int first = 1;
for (qp = list->q_back; qp != list; qp = next) {
next = qp->q_back;
mlp = (struct ulist *)qp;
for (qp = list->q_back; qp != list; qp = next) {
next = qp->q_back;
mlp = (struct ulist *)qp;
- getship(mlp->unit.ship.shp_uid, &ship);
- if (ship.shp_own != actor) {
+ sp = &mlp->unit.ship;
+ getship(sp->shp_uid, sp);
+ if (sp->shp_own != actor) {
mpr(actor, "%s was sunk at %s\n",
mpr(actor, "%s was sunk at %s\n",
- prship(&ship), xyas(ship.shp_x, ship.shp_y, actor));
+ prship(sp), xyas(sp->shp_x, sp->shp_y, actor));
emp_remque((struct emp_qelem *)mlp);
free(mlp);
continue;
}
if (opt_SAIL) {
emp_remque((struct emp_qelem *)mlp);
free(mlp);
continue;
}
if (opt_SAIL) {
- if (*ship.shp_path && !update_running) {
+ if (*sp->shp_path && !update_running) {
shp_stays(actor, "has a sail path", mlp);
mpr(actor, "Use `sail <#> -' to reset\n");
continue;
}
}
/* check crew - uws don't count */
shp_stays(actor, "has a sail path", mlp);
mpr(actor, "Use `sail <#> -' to reset\n");
continue;
}
}
/* check crew - uws don't count */
- if (ship.shp_item[I_MILIT] == 0 && ship.shp_item[I_CIVIL] == 0) {
+ if (sp->shp_item[I_MILIT] == 0 && sp->shp_item[I_CIVIL] == 0) {
shp_stays(actor, "is crewless", mlp);
continue;
}
shp_stays(actor, "is crewless", mlp);
continue;
}
- if (!getsect(ship.shp_x, ship.shp_y, §)) {
+ if (!getsect(sp->shp_x, sp->shp_y, §)) {
shp_stays(actor, "was sucked into the sky by a strange looking spaceship", mlp); /* heh -KHS */
continue;
}
shp_stays(actor, "was sucked into the sky by a strange looking spaceship", mlp); /* heh -KHS */
continue;
}
- switch (shp_check_nav(§, &ship)) {
+ switch (shp_check_nav(§, sp)) {
case CN_CONSTRUCTION:
shp_stays(actor, "is caught in a construction zone", mlp);
continue;
case CN_CONSTRUCTION:
shp_stays(actor, "is caught in a construction zone", mlp);
continue;
- allx = ship.shp_x;
- ally = ship.shp_y;
+ allx = sp->shp_x;
+ ally = sp->shp_y;
- if (ship.shp_x != allx || ship.shp_y != ally)
+ if (sp->shp_x != allx || sp->shp_y != ally)
- if (ship.shp_mobil + 1 < (int)mlp->mobil) {
- mlp->mobil = ship.shp_mobil;
+ if (sp->shp_mobil + 1 < (int)mlp->mobil) {
+ mlp->mobil = sp->shp_mobil;
}
if (mlp->mobil < *minmobp)
*minmobp = mlp->mobil;
if (mlp->mobil > *maxmobp)
*maxmobp = mlp->mobil;
}
if (mlp->mobil < *minmobp)
*minmobp = mlp->mobil;
if (mlp->mobil > *maxmobp)
*maxmobp = mlp->mobil;