nim-libp2p-experimental/libp2p/protocols/pubsub/mcache.nim

64 lines
1.6 KiB
Nim

## Nim-LibP2P
## Copyright (c) 2019 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
import std/[sets, tables, options]
import rpc/[messages]
export sets, tables, messages, options
type
CacheEntry* = object
mid*: MessageID
topicIDs*: seq[string]
MCache* = object of RootObj
msgs*: Table[MessageID, Message]
history*: seq[seq[CacheEntry]]
historySize*: Natural
windowSize*: Natural
func get*(c: MCache, mid: MessageID): Option[Message] =
result = none(Message)
if mid in c.msgs:
result = some(c.msgs[mid])
func contains*(c: MCache, mid: MessageID): bool =
c.get(mid).isSome
func put*(c: var MCache, msgId: MessageID, msg: Message) =
if msgId notin c.msgs:
c.msgs[msgId] = msg
c.history[0].add(CacheEntry(mid: msgId, topicIDs: msg.topicIDs))
func window*(c: MCache, topic: string): HashSet[MessageID] =
result = initHashSet[MessageID]()
let
len = min(c.windowSize, c.history.len)
for i in 0..<len:
for entry in c.history[i]:
for t in entry.topicIDs:
if t == topic:
result.incl(entry.mid)
break
func shift*(c: var MCache) =
for entry in c.history.pop():
c.msgs.del(entry.mid)
c.history.insert(@[])
func init*(T: type MCache, window, history: Natural): T =
T(
history: newSeq[seq[CacheEntry]](history),
historySize: history,
windowSize: window
)