lnd.xprv/channeldb/channel_cache.go

51 lines
1.4 KiB
Go

package channeldb
// channelCache is an in-memory cache used to improve the performance of
// ChanUpdatesInHorizon. It caches the chan info and edge policies for a
// particular channel.
type channelCache struct {
n int
channels map[uint64]ChannelEdge
}
// newChannelCache creates a new channelCache with maximum capacity of n
// channels.
func newChannelCache(n int) *channelCache {
return &channelCache{
n: n,
channels: make(map[uint64]ChannelEdge),
}
}
// get returns the channel from the cache, if it exists.
func (c *channelCache) get(chanid uint64) (ChannelEdge, bool) {
channel, ok := c.channels[chanid]
return channel, ok
}
// insert adds the entry to the channel cache. If an entry for chanid already
// exists, it will be replaced with the new entry. If the entry doesn't exist,
// it will be inserted to the cache, performing a random eviction if the cache
// is at capacity.
func (c *channelCache) insert(chanid uint64, channel ChannelEdge) {
// If entry exists, replace it.
if _, ok := c.channels[chanid]; ok {
c.channels[chanid] = channel
return
}
// Otherwise, evict an entry at random and insert.
if len(c.channels) == c.n {
for id := range c.channels {
delete(c.channels, id)
break
}
}
c.channels[chanid] = channel
}
// remove deletes an edge for chanid from the cache, if it exists.
func (c *channelCache) remove(chanid uint64) {
delete(c.channels, chanid)
}