69 lines
1.8 KiB
Nim
69 lines
1.8 KiB
Nim
# Nim-LibP2P
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# Copyright (c) 2023 Status Research & Development GmbH
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# Licensed under either of
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# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
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# * MIT license ([LICENSE-MIT](LICENSE-MIT))
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# at your option.
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# This file may not be copied, modified, or distributed except according to
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# those terms.
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{.push raises: [].}
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import std/[sets, tables]
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import rpc/[messages]
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import results
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export sets, tables, messages, results
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type
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CacheEntry* = object
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msgId*: MessageId
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topic*: string
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MCache* = object of RootObj
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msgs*: Table[MessageId, Message]
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history*: seq[seq[CacheEntry]]
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pos*: int
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windowSize*: Natural
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func get*(c: MCache, msgId: MessageId): Opt[Message] =
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if msgId in c.msgs:
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try: Opt.some(c.msgs[msgId])
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except KeyError: raiseAssert "checked"
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else:
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Opt.none(Message)
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func contains*(c: MCache, msgId: MessageId): bool =
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msgId in c.msgs
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func put*(c: var MCache, msgId: MessageId, msg: Message) =
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if not c.msgs.hasKeyOrPut(msgId, msg):
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# Only add cache entry if the message was not already in the cache
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c.history[c.pos].add(CacheEntry(msgId: msgId, topic: msg.topic))
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func window*(c: MCache, topic: string): HashSet[MessageId] =
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let
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len = min(c.windowSize, c.history.len)
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for i in 0..<len:
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# Work backwards from `pos` in the circular buffer
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for entry in c.history[(c.pos + c.history.len - i) mod c.history.len]:
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if entry.topic == topic:
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result.incl(entry.msgId)
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func shift*(c: var MCache) =
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# Shift circular buffer to write to a new position, clearing it from past
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# iterations
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c.pos = (c.pos + 1) mod c.history.len
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for entry in c.history[c.pos]:
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c.msgs.del(entry.msgId)
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reset(c.history[c.pos])
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func init*(T: type MCache, window, history: Natural): T =
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T(
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history: newSeq[seq[CacheEntry]](history),
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windowSize: window
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)
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