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

76 lines
2.0 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 chronos, chronicles
import tables, options, sets, sequtils
import rpc/[messages, message], timedcache
type
CacheEntry* = object
mid*: string
msg*: Message
MCache* = ref object of RootObj
msgs*: TimedCache[Message]
history*: seq[seq[CacheEntry]]
historySize*: Natural
windowSize*: Natural
proc get*(c: MCache, mid: string): Option[Message] =
result = none(Message)
if mid in c.msgs:
result = some(c.msgs[mid])
proc contains*(c: MCache, mid: string): bool =
c.get(mid).isSome
proc put*(c: MCache, msg: Message) =
proc handler(key: string, val: Message) {.gcsafe.} =
## make sure we remove the message from history
## to keep things consisten
c.history.applyIt(
it.filterIt(it.mid != msg.msgId)
)
if msg.msgId notin c.msgs:
c.msgs.put(msg.msgId, msg, handler = handler)
c.history[0].add(CacheEntry(mid: msg.msgId, msg: msg))
proc window*(c: MCache, topic: string): HashSet[string] =
result = initHashSet[string]()
let len =
if c.windowSize > c.history.len:
c.history.len
else:
c.windowSize
if c.history.len > 0:
for slot in c.history[0..<len]:
for entry in slot:
for t in entry.msg.topicIDs:
if t == topic:
result.incl(entry.msg.msgId)
break
proc shift*(c: MCache) =
while c.history.len > c.historySize:
for entry in c.history.pop():
c.msgs.del(entry.mid)
c.history.insert(@[])
proc newMCache*(window: Natural, history: Natural): MCache =
new result
result.historySize = history
result.windowSize = window
result.history = newSeq[seq[CacheEntry]]()
result.history.add(@[]) # initialize with empty slot
result.msgs = newTimedCache[Message](2.minutes)