1
0
forked from MTSR/mapserver
mapserver/mapblockaccessor/get.go
2023-12-29 16:00:11 +01:00

105 lines
2.0 KiB
Go

package mapblockaccessor
import (
"mapserver/eventbus"
"mapserver/types"
"sync"
"github.com/minetest-go/mapparser"
cache "github.com/patrickmn/go-cache"
"github.com/prometheus/client_golang/prometheus"
"github.com/sirupsen/logrus"
)
var lock = &sync.RWMutex{}
func (a *MapBlockAccessor) GetMapBlock(pos *types.MapBlockCoords) (*mapparser.MapBlock, error) {
cache_enabled := a.maxcount > 0
key := getKey(pos)
if cache_enabled {
//maintenance
cacheBlocks.Set(float64(a.blockcache.ItemCount()))
if a.blockcache.ItemCount() > a.maxcount {
//flush cache
fields := logrus.Fields{
"cached items": a.blockcache.ItemCount(),
"maxcount": a.maxcount,
}
logrus.WithFields(fields).Debug("Flushing cache")
a.blockcache.Flush()
}
//read section
lock.RLock()
cachedblock, found := a.blockcache.Get(key)
if found {
defer lock.RUnlock()
getCacheHitCount.Inc()
if cachedblock == nil {
return nil, nil
} else {
return cachedblock.(*mapparser.MapBlock), nil
}
}
//end read
lock.RUnlock()
timer := prometheus.NewTimer(dbGetDuration)
defer timer.ObserveDuration()
//write section
lock.Lock()
defer lock.Unlock()
//try read
cachedblock, found = a.blockcache.Get(key)
if found {
getCacheHitCount.Inc()
if cachedblock == nil {
return nil, nil
} else {
return cachedblock.(*mapparser.MapBlock), nil
}
}
}
block, err := a.accessor.GetBlock(pos)
if err != nil {
return nil, err
}
if block == nil {
//no mapblock here
if cache_enabled {
cacheBlockCount.Inc()
a.blockcache.Set(key, nil, cache.DefaultExpiration)
}
return nil, nil
}
if cache_enabled {
getCacheMissCount.Inc()
}
mapblock, err := mapparser.Parse(block.Data)
if err != nil {
return nil, err
}
a.Eventbus.Emit(eventbus.MAPBLOCK_RENDERED, types.NewParsedMapblock(mapblock, pos))
if cache_enabled {
cacheBlockCount.Inc()
a.blockcache.Set(key, mapblock, cache.DefaultExpiration)
}
return mapblock, nil
}