Protect map cache by rwlock

diff --git a/src/map.c b/src/map.c
index e3d66ef44eaf44183ee51b276210c7c4dbb64d91..6a7f10cdf48ad127bcfd0d22dfb42ad54ecc3773 100644 (file)
--- a/src/map.c
+++ b/src/map.c
@@ -23,6 +23,7 @@ Map *map_create()
 {
        Map *map = malloc(sizeof(Map));
        pthread_rwlock_init(&map->rwlck, NULL);
+       pthread_rwlock_init(&map->cached_rwlck, NULL);
        map->sectors = array_create(sizeof(MapSector *));
        map->sectors.cmp = &sector_compare;
        map->cached = NULL;
@@ -32,6 +33,7 @@ Map *map_create()
 void map_delete(Map *map, void (*callback)(void *extra))
 {
        pthread_rwlock_destroy(&map->rwlck);
+       pthread_rwlock_destroy(&map->cached_rwlck);
        for (size_t s = 0; s < map->sectors.siz; s++) {
                MapSector *sector = map_get_sector_raw(map, s);
                for (size_t b = 0; b < sector->blocks.siz; b++) {
@@ -93,8 +95,14 @@ MapSector *map_get_sector(Map *map, v2s32 pos, bool create)
 
 MapBlock *map_get_block(Map *map, v3s32 pos, bool create)
 {
-       if (map->cached && map->cached->pos.x == pos.x && map->cached->pos.y == pos.y && map->cached->pos.z == pos.z)
-               return map->cached;
+       MapBlock *cached = NULL;
+
+       pthread_rwlock_rdlock(&map->cached_rwlck);
+       cached = map->cached;
+       pthread_rwlock_unlock(&map->cached_rwlck);
+
+       if (cached && cached->pos.x == pos.x && cached->pos.y == pos.y && cached->pos.z == pos.z)
+               return cached;
 
        MapSector *sector = map_get_sector(map, (v2s32) {pos.x, pos.z}, create);
        if (! sector)
@@ -111,8 +119,14 @@ MapBlock *map_get_block(Map *map, v3s32 pos, bool create)
 
        if (res.success) {
                block = map_get_block_raw(sector, res.index);
-               if (block->state < MBS_READY && ! create)
-                       block = NULL;
+               if (block->state < MBS_READY) {
+                       if (! create)
+                               block = NULL;
+               } else {
+                       pthread_rwlock_wrlock(&map->cached_rwlck);
+                       map->cached = block;
+                       pthread_rwlock_unlock(&map->cached_rwlck);
+               }
        } else if (create) {
                block = map_allocate_block(pos);
                array_insert(&sector->blocks, &block, res.index);
@@ -120,7 +134,7 @@ MapBlock *map_get_block(Map *map, v3s32 pos, bool create)
 
        pthread_rwlock_unlock(&sector->rwlck);
 
-       return map->cached = block;
+       return block;
 }
 
 MapBlock *map_allocate_block(v3s32 pos)

diff --git a/src/map.h b/src/map.h
index 706e3d3acd8209a8a470d2445e52747864ad4a49..853ac94e8ad7a1042d5cd15e29aa481fe644b874 100644 (file)
--- a/src/map.h
+++ b/src/map.h
@@ -50,6 +50,7 @@ typedef struct
 {
        pthread_rwlock_t rwlck;
        Array sectors;
+       pthread_rwlock_t cached_rwlck;
        MapBlock *cached;
 } Map;