nim-codex/codex/blockexchange/engine/pendingblocks.nim

91 lines
2.1 KiB
Nim

## Nim-Codex
## Copyright (c) 2021 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 std/tables
import pkg/upraises
push: {.upraises: [].}
import pkg/questionable
import pkg/chronicles
import pkg/chronos
import pkg/libp2p
import ../../blocktype
logScope:
topics = "codex blockexc pendingblocks"
const
DefaultBlockTimeout* = 10.minutes
type
PendingBlocksManager* = ref object of RootObj
blocks*: Table[Cid, Future[Block]] # pending Block requests
proc getWantHandle*(
p: PendingBlocksManager,
cid: Cid,
timeout = DefaultBlockTimeout): Future[Block] {.async.} =
## Add an event for a block
##
if cid notin p.blocks:
p.blocks[cid] = newFuture[Block]().wait(timeout)
trace "Adding pending future for block", cid = $cid
try:
return await p.blocks[cid]
except CancelledError as exc:
trace "Blocks cancelled", exc = exc.msg, cid = $cid
raise exc
except CatchableError as exc:
trace "Pending WANT failed or expired", exc = exc.msg
finally:
p.blocks.del(cid)
proc resolve*(
p: PendingBlocksManager,
blocks: seq[Block]) =
## Resolve pending blocks
##
for blk in blocks:
# resolve any pending blocks
if blk.cid in p.blocks:
p.blocks.withValue(blk.cid, pending):
if not pending[].finished:
trace "Resolving block", cid = $blk.cid
pending[].complete(blk)
p.blocks.del(blk.cid)
proc pending*(
p: PendingBlocksManager,
cid: Cid): bool = cid in p.blocks
proc contains*(
p: PendingBlocksManager,
cid: Cid): bool = p.pending(cid)
iterator wantList*(p: PendingBlocksManager): Cid =
for k in p.blocks.keys:
yield k
iterator wantHandles*(p: PendingBlocksManager): Future[Block] =
for v in p.blocks.values:
yield v
func len*(p: PendingBlocksManager): int =
p.blocks.len
func new*(T: type PendingBlocksManager): T =
T(
blocks: initTable[Cid, Future[Block]]())