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

64 lines
1.6 KiB
Nim

# Nim-LibP2P
# Copyright (c) 2022 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.
{.push raises: [Defect].}
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]]
windowSize*: Natural
func get*(c: MCache, mid: MessageId): Option[Message] =
if mid in c.msgs:
try: some(c.msgs[mid])
except KeyError: raiseAssert "checked"
else:
none(Message)
func contains*(c: MCache, mid: MessageId): bool =
mid in c.msgs
func put*(c: var MCache, msgId: MessageId, msg: Message) =
if not c.msgs.hasKeyOrPut(msgId, msg):
# Only add cache entry if the message was not already in the cache
c.history[0].add(CacheEntry(mid: msgId, topicIds: msg.topicIds))
func window*(c: MCache, topic: string): HashSet[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),
windowSize: window
)