345 lines
9.1 KiB
Nim
345 lines
9.1 KiB
Nim
## Nim-Dagger
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## Copyright (c) 2021 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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import std/sequtils
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import std/algorithm
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import pkg/chronos
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import pkg/chronicles
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import pkg/libp2p
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import pkg/libp2p/errors
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import ./protobuf/bitswap as pb
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import ../blocktype as bt
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import ../stores/blockstore
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import ../utils/asyncheapqueue
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import ./network
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import ./pendingblocks
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import ./peercontext
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export peercontext
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logScope:
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topics = "dagger bitswap engine"
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const
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DefaultTimeout* = 5.seconds
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DefaultMaxPeersPerRequest* = 10
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type
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TaskHandler* = proc(task: BitswapPeerCtx): Future[void] {.gcsafe.}
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TaskScheduler* = proc(task: BitswapPeerCtx): bool {.gcsafe.}
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BitswapEngine* = ref object of RootObj
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localStore*: BlockStore # where we localStore blocks for this instance
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peers*: seq[BitswapPeerCtx] # peers we're currently actively exchanging with
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wantList*: seq[Cid] # local wants list
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pendingBlocks*: PendingBlocksManager # blocks we're awaiting to be resolved
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peersPerRequest: int # max number of peers to request from
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scheduleTask*: TaskScheduler # schedule a new task with the task runner
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request*: BitswapRequest # bitswap network requests
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wallet*: Wallet # nitro wallet for micropayments
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pricing*: ?Pricing # optional bandwidth pricing
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proc contains*(a: AsyncHeapQueue[Entry], b: Cid): bool =
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## Convenience method to check for entry prepense
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##
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a.anyIt( it.cid == b )
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proc getPeerCtx*(b: BitswapEngine, peerId: PeerID): BitswapPeerCtx =
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## Get the peer's context
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##
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let peer = b.peers.filterIt( it.id == peerId )
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if peer.len > 0:
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return peer[0]
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proc requestBlocks*(
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b: BitswapEngine,
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cids: seq[Cid],
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timeout = DefaultTimeout): seq[Future[bt.Block]] =
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## Request a block from remotes
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##
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# no Cids to request
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if cids.len == 0:
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return
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if b.peers.len <= 0:
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warn "No peers to request blocks from"
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# TODO: run discovery here to get peers for the block
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return
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var blocks: seq[Future[bt.Block]]
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for c in cids:
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if c notin b.pendingBlocks:
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# install events to await blocks incoming from different sources
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blocks.add(
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b.pendingBlocks.addOrAwait(c).wait(timeout))
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proc cmp(a, b: BitswapPeerCtx): int =
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if a.debtRatio == b.debtRatio:
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0
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elif a.debtRatio > b.debtRatio:
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1
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else:
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-1
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# sort the peers so that we request
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# the blocks from a peer with the lowest
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# debt ratio
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var sortedPeers = b.peers.sorted(
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cmp
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)
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# get the first peer with at least one (any)
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# matching cid
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var blockPeer: BitswapPeerCtx
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for i, p in sortedPeers:
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let has = cids.anyIt(
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it in p.peerHave
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)
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if has:
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blockPeer = p
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break
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# didn't find any peer with matching cids
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# use the first one in the sorted array
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if isNil(blockPeer):
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blockPeer = sortedPeers[0]
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sortedPeers.keepItIf(
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it != blockPeer
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)
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trace "Requesting blocks from peer", peer = blockPeer.id, len = cids.len
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# request block
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b.request.sendWantList(
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blockPeer.id,
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cids,
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wantType = WantType.wantBlock) # we want this remote to send us a block
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if sortedPeers.len == 0:
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return blocks # no peers to send wants to
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template sendWants(ctx: BitswapPeerCtx) =
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# just send wants
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b.request.sendWantList(
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ctx.id,
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cids.filterIt( it notin ctx.peerHave ), # filter out those that we already know about
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wantType = WantType.wantHave) # we only want to know if the peer has the block
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# filter out the peer we've already requested from
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var stop = sortedPeers.high
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if stop > b.peersPerRequest: stop = b.peersPerRequest
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trace "Sending want list requests to remaining peers", count = stop + 1
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for p in sortedPeers[0..stop]:
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sendWants(p)
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return blocks
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proc blockPresenceHandler*(
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b: BitswapEngine,
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peer: PeerID,
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presence: seq[BlockPresence]) =
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## Handle block presence
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##
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let peerCtx = b.getPeerCtx(peer)
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if isNil(peerCtx):
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return
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for blk in presence:
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let cid = Cid.init(blk.cid).get()
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if cid notin peerCtx.peerHave:
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if blk.type == BlockPresenceType.presenceHave:
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peerCtx.peerHave.add(cid)
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proc scheduleTasks(b: BitswapEngine, blocks: seq[bt.Block]) =
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trace "Schedule a task for new blocks"
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let cids = blocks.mapIt( it.cid )
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# schedule any new peers to provide blocks to
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for p in b.peers:
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for c in cids: # for each cid
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# schedule a peer if it wants at least one
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# cid and we have it in our local store
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if c in p.peerWants and c in b.localStore:
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if not b.scheduleTask(p):
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trace "Unable to schedule task for peer", peer = p.id
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break # do next peer
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proc resolveBlocks*(b: BitswapEngine, blocks: seq[bt.Block]) =
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## Resolve pending blocks from the pending blocks manager
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## and schedule any new task to be ran
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##
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trace "Resolving blocks"
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b.pendingBlocks.resolve(blocks)
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b.scheduleTasks(blocks)
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proc blocksHandler*(
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b: BitswapEngine,
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peer: PeerID,
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blocks: seq[bt.Block]) =
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## handle incoming blocks
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##
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trace "Got blocks from peer", peer, len = blocks.len
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b.localStore.putBlocks(blocks)
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b.resolveBlocks(blocks)
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proc wantListHandler*(
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b: BitswapEngine,
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peer: PeerID,
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wantList: WantList) =
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## Handle incoming want lists
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##
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trace "Got want list for peer", peer
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let peerCtx = b.getPeerCtx(peer)
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if isNil(peerCtx):
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return
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var dontHaves: seq[Cid]
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let entries = wantList.entries
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for e in entries:
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let idx = peerCtx.peerWants.find(e)
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if idx > -1:
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# peer doesn't want this block anymore
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if e.cancel:
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peerCtx.peerWants.del(idx)
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continue
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peerCtx.peerWants[idx] = e # update entry
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else:
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peerCtx.peerWants.add(e)
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trace "Added entry to peer's want list", peer = peerCtx.id, cid = $e.cid
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# peer might want to ask for the same cid with
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# different want params
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if e.sendDontHave and not(b.localStore.hasBlock(e.cid)):
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dontHaves.add(e.cid)
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# send don't have's to remote
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if dontHaves.len > 0:
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b.request.sendPresence(
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peer,
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dontHaves.mapIt(
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BlockPresence(
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cid: it.data.buffer,
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`type`: BlockPresenceType.presenceDontHave)))
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if not b.scheduleTask(peerCtx):
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trace "Unable to schedule task for peer", peer
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proc pricingHandler*(engine: BitswapEngine, peer: PeerID, pricing: Pricing) =
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let context = engine.getPeerCtx(peer)
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if context.isNil:
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return
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context.pricing = pricing.some
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proc setupPeer*(b: BitswapEngine, peer: PeerID) =
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## Perform initial setup, such as want
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## list exchange
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##
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trace "Setting up new peer", peer
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if peer notin b.peers:
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b.peers.add(BitswapPeerCtx(
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id: peer
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))
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# broadcast our want list, the other peer will do the same
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if b.wantList.len > 0:
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b.request.sendWantList(peer, b.wantList, full = true)
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if b.pricing.isSome:
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b.request.sendPricing(peer, b.pricing.get)
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proc dropPeer*(b: BitswapEngine, peer: PeerID) =
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## Cleanup disconnected peer
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##
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trace "Dropping peer", peer
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# drop the peer from the peers table
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b.peers.keepItIf( it.id != peer )
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proc taskHandler*(b: BitswapEngine, task: BitswapPeerCtx) {.gcsafe, async.} =
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trace "Handling task for peer", peer = task.id
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var wantsBlocks = newAsyncHeapQueue[Entry](queueType = QueueType.Max)
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# get blocks and wants to send to the remote
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for e in task.peerWants:
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if e.wantType == WantType.wantBlock:
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await wantsBlocks.push(e)
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# TODO: There should be all sorts of accounting of
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# bytes sent/received here
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if wantsBlocks.len > 0:
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let blocks = await b.localStore.getBlocks(
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wantsBlocks.mapIt(
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it.cid
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))
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if blocks.len > 0:
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b.request.sendBlocks(task.id, blocks)
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# Remove successfully sent blocks
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task.peerWants.keepIf(
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proc(e: Entry): bool =
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not blocks.anyIt( it.cid == e.cid )
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)
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var wants: seq[BlockPresence]
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# do not remove wants from the queue unless
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# we send the block or get a cancel
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for e in task.peerWants:
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if e.wantType == WantType.wantHave:
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wants.add(
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BlockPresence(
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cid: e.`block`,
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`type`: if b.localStore.hasBlock(e.cid):
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BlockPresenceType.presenceHave
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else:
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BlockPresenceType.presenceDontHave
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))
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if wants.len > 0:
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b.request.sendPresence(task.id, wants)
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proc new*(
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T: type BitswapEngine,
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localStore: BlockStore,
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wallet: Wallet,
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request: BitswapRequest = BitswapRequest(),
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scheduleTask: TaskScheduler = nil,
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peersPerRequest = DefaultMaxPeersPerRequest): T =
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proc taskScheduler(task: BitswapPeerCtx): bool =
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if not isNil(scheduleTask):
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return scheduleTask(task)
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let b = BitswapEngine(
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localStore: localStore,
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pendingBlocks: PendingBlocksManager.new(),
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peersPerRequest: peersPerRequest,
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scheduleTask: taskScheduler,
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request: request,
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wallet: wallet
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)
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return b
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