nwaku/waku/waku_api/message_cache.nim

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when (NimMajor, NimMinor) < (1, 4):
{.push raises: [Defect].}
else:
{.push raises: [].}
import
std/[sequtils, sugar, algorithm, options],
stew/results,
chronicles,
chronos,
libp2p/protocols/pubsub
import
../waku_core
logScope:
topics = "waku node message_cache"
const DefaultMessageCacheCapacity: int = 50
type MessageCache* = ref object
pubsubTopics: seq[PubsubTopic]
contentTopics: seq[ContentTopic]
pubsubIndex: seq[tuple[pubsubIdx: int, msgIdx: int]]
contentIndex: seq[tuple[contentIdx: int, msgIdx: int]]
messages: seq[WakuMessage]
capacity: int
func `$`*(self: MessageCache): string =
"Messages: " & $self.messages.len &
" \nPubsubTopics: " & $self.pubsubTopics &
" \nContentTopics: " & $self.contentTopics &
" \nPubsubIndex: " & $self.pubsubIndex &
" \nContentIndex: " & $self.contentIndex
func init*(T: type MessageCache, capacity=DefaultMessageCacheCapacity): T =
MessageCache(
capacity: capacity
)
proc messagesCount*(self: MessageCache): int =
self.messages.len
proc pubsubTopicCount*(self: MessageCache): int =
self.pubsubTopics.len
proc contentTopicCount*(self: MessageCache): int =
self.contentTopics.len
proc pubsubSearch(self: MessageCache, pubsubTopic: PubsubTopic): Option[int] =
# Return some with the index if found none otherwise.
for i, topic in self.pubsubTopics:
if topic == pubsubTopic:
return some(i)
return none(int)
proc contentSearch(self: MessageCache, contentTopic: ContentTopic): Option[int] =
# Return some with the index if found none otherwise.
for i, topic in self.contentTopics:
if topic == contentTopic:
return some(i)
return none(int)
proc isPubsubSubscribed*(self: MessageCache, pubsubTopic: PubsubTopic): bool =
self.pubsubSearch(pubsubTopic).isSome()
proc isContentSubscribed*(self: MessageCache, contentTopic: ContentTopic): bool =
self.contentSearch(contentTopic).isSome()
proc pubsubSubscribe*(self: MessageCache, pubsubTopic: PubsubTopic) =
if self.pubsubSearch(pubsubTopic).isNone():
self.pubsubTopics.add(pubsubTopic)
proc contentSubscribe*(self: MessageCache, contentTopic: ContentTopic) =
if self.contentSearch(contentTopic).isNone():
self.contentTopics.add(contentTopic)
proc removeMessage(self: MessageCache, idx: int) =
# get last index because del() is a swap
let lastIndex = self.messages.high
self.messages.del(idx)
# update indices
var j = self.pubsubIndex.high
while j > -1:
let (pId, mId) = self.pubsubIndex[j]
if mId == idx:
self.pubsubIndex.del(j)
elif mId == lastIndex:
self.pubsubIndex[j] = (pId, idx)
dec(j)
j = self.contentIndex.high
while j > -1:
let (cId, mId) = self.contentIndex[j]
if mId == idx:
self.contentIndex.del(j)
elif mId == lastIndex:
self.contentIndex[j] = (cId, idx)
dec(j)
proc pubsubUnsubscribe*(self: MessageCache, pubsubTopic: PubsubTopic) =
let pubsubIdxOp = self.pubsubSearch(pubsubTopic)
let pubsubIdx =
if pubsubIdxOp.isSome(): pubsubIdxOp.get()
else: return
let lastIndex = self.pubsubTopics.high
self.pubsubTopics.del(pubsubIdx)
var msgIndices = newSeq[int](0)
var j = self.pubsubIndex.high
while j > -1:
let (pId, mId) = self.pubsubIndex[j]
if pId == pubsubIdx:
# remove index for this topic
self.pubsubIndex.del(j)
msgIndices.add(mId)
elif pId == lastIndex:
# swap the index because pubsubTopics.del() is a swap
self.pubsubIndex[j] = (pubsubIdx, mId)
dec(j)
# check if messages on this pubsub topic are indexed by any content topic, if not remove them.
for mId in msgIndices:
if not self.contentIndex.anyIt(it.msgIdx == mId):
self.removeMessage(mId)
proc contentUnsubscribe*(self: MessageCache, contentTopic: ContentTopic) =
let contentIdxOP = self.contentSearch(contentTopic)
let contentIdx =
if contentIdxOP.isSome(): contentIdxOP.get()
else: return
let lastIndex = self.contentTopics.high
self.contentTopics.del(contentIdx)
var msgIndices = newSeq[int](0)
var j = self.contentIndex.high
while j > -1:
let (cId, mId) = self.contentIndex[j]
if cId == contentIdx:
# remove indices for this topic
self.contentIndex.del(j)
msgIndices.add(mId)
elif cId == lastIndex:
# swap the indices because contentTopics.del() is a swap
self.contentIndex[j] = (contentIdx, mId)
dec(j)
# check if messages on this content topic are indexed by any pubsub topic, if not remove them.
for mId in msgIndices:
if not self.pubsubIndex.anyIt(it.msgIdx == mId):
self.removeMessage(mId)
proc reset*(self: MessageCache) =
self.messages.setLen(0)
self.pubsubTopics.setLen(0)
self.contentTopics.setLen(0)
self.pubsubIndex.setLen(0)
self.contentIndex.setLen(0)
proc addMessage*(
self: MessageCache,
pubsubTopic: PubsubTopic,
msg: WakuMessage
) =
## Idempotent message addition.
var oldestTime = int64.high
var oldestMsg = int.high
for i, message in self.messages.reversed:
if message == msg:
return
if message.timestamp < oldestTime:
oldestTime = message.timestamp
oldestMsg = i
# reverse index
oldestMsg = self.messages.high - oldestMsg
var pubsubIdxOp = self.pubsubSearch(pubsubTopic)
var contentIdxOp = self.contentSearch(msg.contentTopic)
if pubsubIdxOp.isNone() and contentIdxOp.isNone():
return
let pubsubIdx =
if pubsubIdxOp.isNone():
self.pubsubTopics.add(pubsubTopic)
self.pubsubTopics.high
else:
pubsubIdxOp.get()
let contentIdx =
if contentIdxOp.isNone():
self.contentTopics.add(msg.contentTopic)
self.contentTopics.high
else:
contentIdxOp.get()
# add the message, make space if needed
if self.messages.len >= self.capacity:
self.removeMessage(oldestMsg)
let msgIdx = self.messages.len
self.messages.add(msg)
self.pubsubIndex.add((pubsubIdx, msgIdx))
self.contentIndex.add((contentIdx, msgIdx))
proc getMessages*(
self: MessageCache,
pubsubTopic: PubsubTopic,
clear=false
): Result[seq[WakuMessage], string] =
## Return all messages on this pubsub topic
if self.pubsubTopics.len == 0:
return err("not subscribed to any pubsub topics")
let pubsubIdxOp = self.pubsubSearch(pubsubTopic)
let pubsubIdx =
if pubsubIdxOp.isNone:
return err("not subscribed to this pubsub topic")
else: pubsubIdxOp.get()
let msgIndices = collect:
for (pId, mId) in self.pubsubIndex:
if pId == pubsubIdx:
mId
let messages = msgIndices.mapIt(self.messages[it])
if clear:
for idx in msgIndices.reversed:
self.removeMessage(idx)
return ok(messages)
proc getAutoMessages*(
self: MessageCache,
contentTopic: ContentTopic,
clear=false
): Result[seq[WakuMessage], string] =
## Return all messages on this content topic
if self.contentTopics.len == 0:
return err("not subscribed to any content topics")
let contentIdxOp = self.contentSearch(contentTopic)
let contentIdx =
if contentIdxOp.isNone():
return err("not subscribed to this content topic")
else: contentIdxOp.get()
let msgIndices = collect:
for (cId, mId) in self.contentIndex:
if cId == contentIdx:
mId
let messages = msgIndices.mapIt(self.messages[it])
if clear:
for idx in msgIndices.reversed:
self.removeMessage(idx)
return ok(messages)