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Fix navigate not to wipe out concurrent updates

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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.
This commit is contained in:
Markus Armbruster 2012-05-17 20:33:34 +02:00
parent 0700d97fe3
commit a694e49343
1 changed files with 14 additions and 14 deletions
Download patch file Download diff file Expand all files Collapse all files

28
src/lib/subs/shpsub.c
View file

@ -100,8 +100,8 @@ shp_nav(struct emp_qelem *list, double *minmobp, double *maxmobp,
struct emp_qelem *qp;
struct emp_qelem *next;
struct ulist *mlp;
struct shpstr *sp;
struct sctstr sect;
struct shpstr ship;
coord allx;
coord ally;
int first = 1;
@ -112,31 +112,32 @@ shp_nav(struct emp_qelem *list, double *minmobp, double *maxmobp,
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",
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) {
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 */
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;
}
if (!getsect(ship.shp_x, ship.shp_y, &sect)) {
if (!getsect(sp->shp_x, sp->shp_y, &sect)) {
shp_stays(actor, "was sucked into the sky by a strange looking spaceship", mlp); /* heh -KHS */
continue;
}
switch (shp_check_nav(&sect, &ship)) {
switch (shp_check_nav(&sect, sp)) {
case CN_CONSTRUCTION:
shp_stays(actor, "is caught in a construction zone", mlp);
continue;
@ -151,20 +152,19 @@ shp_nav(struct emp_qelem *list, double *minmobp, double *maxmobp,
continue;
}
if (first) {
allx = ship.shp_x;
ally = ship.shp_y;
allx = sp->shp_x;
ally = sp->shp_y;
first = 0;
}
if (ship.shp_x != allx || ship.shp_y != ally)
if (sp->shp_x != allx || sp->shp_y != ally)
*togetherp = 0;
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;
mlp->unit.ship = ship;
}
}