{-# LANGUAGE BangPatterns               #-}
{-# LANGUAGE DataKinds                  #-}
{-# LANGUAGE DeriveGeneric              #-}
{-# LANGUAGE DerivingStrategies         #-}
{-# LANGUAGE DuplicateRecordFields      #-}
{-# LANGUAGE ExistentialQuantification  #-}
{-# LANGUAGE FlexibleContexts           #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE LambdaCase                 #-}
{-# LANGUAGE MultiWayIf                 #-}
{-# LANGUAGE NamedFieldPuns             #-}
{-# LANGUAGE ScopedTypeVariables        #-}
{-# LANGUAGE StandaloneDeriving         #-}
{-# LANGUAGE TupleSections              #-}
{-# LANGUAGE TypeApplications           #-}
{-# LANGUAGE TypeFamilies               #-}
{-# LANGUAGE UndecidableInstances       #-}

{-# OPTIONS_GHC -fno-strictness #-}
-- NOTE: With @-fstrictness@ optimisation (enabled by default for -O1), we get
-- an unexplained thunk in 'KnownIntersectionState' and thus a space leak. See
-- #1356.

module Ouroboros.Consensus.MiniProtocol.ChainSync.Client (
    Consensus
  , chainSyncClient
  , bracketChainSyncClient
  , ChainSyncClientResult (..)
  , ChainSyncClientException (..)
  , ChainDbView (..)
  , defaultChainDbView
  , Our (..)
  , Their (..)
    -- * Trace events
  , TraceChainSyncClientEvent (..)
  , InvalidBlockReason
  ) where

import           Control.Monad
import           Control.Monad.Except
import           Control.Tracer
import qualified Data.Foldable as Foldable
import           Data.Kind (Type)
import           Data.Map.Strict (Map)
import qualified Data.Map.Strict as Map
import           Data.Proxy
import           Data.Typeable
import           Data.Word (Word64)
import           GHC.Generics (Generic)
import           GHC.Stack (HasCallStack)
import           NoThunks.Class (unsafeNoThunks)

import           Network.TypedProtocol.Pipelined
import           Ouroboros.Network.AnchoredFragment (AnchoredFragment (..))
import qualified Ouroboros.Network.AnchoredFragment as AF
import           Ouroboros.Network.Block (Tip, getTipBlockNo, getTipPoint)
import           Ouroboros.Network.Mux (ControlMessage (..), ControlMessageSTM)
import           Ouroboros.Network.Protocol.ChainSync.ClientPipelined
import           Ouroboros.Network.Protocol.ChainSync.PipelineDecision

import           Ouroboros.Consensus.Block
import           Ouroboros.Consensus.Config
import           Ouroboros.Consensus.Forecast
import           Ouroboros.Consensus.HeaderStateHistory
                     (HeaderStateHistory (..), validateHeader)
import qualified Ouroboros.Consensus.HeaderStateHistory as HeaderStateHistory
import           Ouroboros.Consensus.HeaderValidation hiding (validateHeader)
import           Ouroboros.Consensus.Ledger.Extended
import           Ouroboros.Consensus.Ledger.SupportsProtocol
import           Ouroboros.Consensus.Node.NetworkProtocolVersion
import           Ouroboros.Consensus.Protocol.Abstract
import           Ouroboros.Consensus.Util
import           Ouroboros.Consensus.Util.Assert (assertWithMsg)
import           Ouroboros.Consensus.Util.IOLike
import           Ouroboros.Consensus.Util.ResourceRegistry
import           Ouroboros.Consensus.Util.STM (WithFingerprint (..),
                     onEachChange)

import           Ouroboros.Consensus.Storage.ChainDB (ChainDB,
                     InvalidBlockReason)
import qualified Ouroboros.Consensus.Storage.ChainDB as ChainDB

type Consensus (client :: Type -> Type -> Type -> (Type -> Type) -> Type -> Type) blk m =
   client (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult

-- | Abstract over the ChainDB
data ChainDbView m blk = ChainDbView {
      ChainDbView m blk -> STM m (AnchoredFragment (Header blk))
getCurrentChain       :: STM m (AnchoredFragment (Header blk))
    , ChainDbView m blk -> STM m (HeaderStateHistory blk)
getHeaderStateHistory :: STM m (HeaderStateHistory blk)
    , ChainDbView m blk
-> Point blk -> STM m (Maybe (ExtLedgerState blk))
getPastLedger         :: Point blk -> STM m (Maybe (ExtLedgerState blk))
    , ChainDbView m blk
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock     :: STM m (WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
    }

defaultChainDbView :: ChainDB m blk -> ChainDbView m blk
defaultChainDbView :: ChainDB m blk -> ChainDbView m blk
defaultChainDbView ChainDB m blk
chainDB = ChainDbView :: forall (m :: * -> *) blk.
STM m (AnchoredFragment (Header blk))
-> STM m (HeaderStateHistory blk)
-> (Point blk -> STM m (Maybe (ExtLedgerState blk)))
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> ChainDbView m blk
ChainDbView {
      $sel:getCurrentChain:ChainDbView :: STM m (AnchoredFragment (Header blk))
getCurrentChain       = ChainDB m blk -> STM m (AnchoredFragment (Header blk))
forall (m :: * -> *) blk.
ChainDB m blk -> STM m (AnchoredFragment (Header blk))
ChainDB.getCurrentChain       ChainDB m blk
chainDB
    , $sel:getHeaderStateHistory:ChainDbView :: STM m (HeaderStateHistory blk)
getHeaderStateHistory = ChainDB m blk -> STM m (HeaderStateHistory blk)
forall (m :: * -> *) blk.
ChainDB m blk -> STM m (HeaderStateHistory blk)
ChainDB.getHeaderStateHistory ChainDB m blk
chainDB
    , $sel:getPastLedger:ChainDbView :: Point blk -> STM m (Maybe (ExtLedgerState blk))
getPastLedger         = ChainDB m blk -> Point blk -> STM m (Maybe (ExtLedgerState blk))
forall (m :: * -> *) blk.
ChainDB m blk -> Point blk -> STM m (Maybe (ExtLedgerState blk))
ChainDB.getPastLedger         ChainDB m blk
chainDB
    , $sel:getIsInvalidBlock:ChainDbView :: STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock     = ChainDB m blk
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
forall (m :: * -> *) blk.
ChainDB m blk
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
ChainDB.getIsInvalidBlock     ChainDB m blk
chainDB
    }

-- newtype wrappers to avoid confusing our tip with their tip.
newtype Their a = Their { Their a -> a
unTheir :: a }
  deriving stock   (Their a -> Their a -> Bool
(Their a -> Their a -> Bool)
-> (Their a -> Their a -> Bool) -> Eq (Their a)
forall a. Eq a => Their a -> Their a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Their a -> Their a -> Bool
$c/= :: forall a. Eq a => Their a -> Their a -> Bool
== :: Their a -> Their a -> Bool
$c== :: forall a. Eq a => Their a -> Their a -> Bool
Eq)
  deriving newtype (Int -> Their a -> ShowS
[Their a] -> ShowS
Their a -> String
(Int -> Their a -> ShowS)
-> (Their a -> String) -> ([Their a] -> ShowS) -> Show (Their a)
forall a. Show a => Int -> Their a -> ShowS
forall a. Show a => [Their a] -> ShowS
forall a. Show a => Their a -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Their a] -> ShowS
$cshowList :: forall a. Show a => [Their a] -> ShowS
show :: Their a -> String
$cshow :: forall a. Show a => Their a -> String
showsPrec :: Int -> Their a -> ShowS
$cshowsPrec :: forall a. Show a => Int -> Their a -> ShowS
Show, Context -> Their a -> IO (Maybe ThunkInfo)
Proxy (Their a) -> String
(Context -> Their a -> IO (Maybe ThunkInfo))
-> (Context -> Their a -> IO (Maybe ThunkInfo))
-> (Proxy (Their a) -> String)
-> NoThunks (Their a)
forall a. NoThunks a => Context -> Their a -> IO (Maybe ThunkInfo)
forall a. NoThunks a => Proxy (Their a) -> String
forall a.
(Context -> a -> IO (Maybe ThunkInfo))
-> (Context -> a -> IO (Maybe ThunkInfo))
-> (Proxy a -> String)
-> NoThunks a
showTypeOf :: Proxy (Their a) -> String
$cshowTypeOf :: forall a. NoThunks a => Proxy (Their a) -> String
wNoThunks :: Context -> Their a -> IO (Maybe ThunkInfo)
$cwNoThunks :: forall a. NoThunks a => Context -> Their a -> IO (Maybe ThunkInfo)
noThunks :: Context -> Their a -> IO (Maybe ThunkInfo)
$cnoThunks :: forall a. NoThunks a => Context -> Their a -> IO (Maybe ThunkInfo)
NoThunks)

newtype Our   a = Our   { Our a -> a
unOur   :: a }
  deriving stock   (Our a -> Our a -> Bool
(Our a -> Our a -> Bool) -> (Our a -> Our a -> Bool) -> Eq (Our a)
forall a. Eq a => Our a -> Our a -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: Our a -> Our a -> Bool
$c/= :: forall a. Eq a => Our a -> Our a -> Bool
== :: Our a -> Our a -> Bool
$c== :: forall a. Eq a => Our a -> Our a -> Bool
Eq)
  deriving newtype (Int -> Our a -> ShowS
[Our a] -> ShowS
Our a -> String
(Int -> Our a -> ShowS)
-> (Our a -> String) -> ([Our a] -> ShowS) -> Show (Our a)
forall a. Show a => Int -> Our a -> ShowS
forall a. Show a => [Our a] -> ShowS
forall a. Show a => Our a -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [Our a] -> ShowS
$cshowList :: forall a. Show a => [Our a] -> ShowS
show :: Our a -> String
$cshow :: forall a. Show a => Our a -> String
showsPrec :: Int -> Our a -> ShowS
$cshowsPrec :: forall a. Show a => Int -> Our a -> ShowS
Show, Context -> Our a -> IO (Maybe ThunkInfo)
Proxy (Our a) -> String
(Context -> Our a -> IO (Maybe ThunkInfo))
-> (Context -> Our a -> IO (Maybe ThunkInfo))
-> (Proxy (Our a) -> String)
-> NoThunks (Our a)
forall a. NoThunks a => Context -> Our a -> IO (Maybe ThunkInfo)
forall a. NoThunks a => Proxy (Our a) -> String
forall a.
(Context -> a -> IO (Maybe ThunkInfo))
-> (Context -> a -> IO (Maybe ThunkInfo))
-> (Proxy a -> String)
-> NoThunks a
showTypeOf :: Proxy (Our a) -> String
$cshowTypeOf :: forall a. NoThunks a => Proxy (Our a) -> String
wNoThunks :: Context -> Our a -> IO (Maybe ThunkInfo)
$cwNoThunks :: forall a. NoThunks a => Context -> Our a -> IO (Maybe ThunkInfo)
noThunks :: Context -> Our a -> IO (Maybe ThunkInfo)
$cnoThunks :: forall a. NoThunks a => Context -> Our a -> IO (Maybe ThunkInfo)
NoThunks)

bracketChainSyncClient
    :: ( IOLike m
       , Ord peer
       , BlockSupportsProtocol blk
       , LedgerSupportsProtocol blk
       )
    => Tracer m (TraceChainSyncClientEvent blk)
    -> ChainDbView m blk
    -> StrictTVar m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
       -- ^ The candidate chains, we need the whole map because we
       -- (de)register nodes (@peer@).
    -> peer
    -> (    StrictTVar m (AnchoredFragment (Header blk))
         -> m a
       )
    -> m a
bracketChainSyncClient :: Tracer m (TraceChainSyncClientEvent blk)
-> ChainDbView m blk
-> StrictTVar
     m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> peer
-> (StrictTVar m (AnchoredFragment (Header blk)) -> m a)
-> m a
bracketChainSyncClient Tracer m (TraceChainSyncClientEvent blk)
tracer ChainDbView { STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock :: STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
$sel:getIsInvalidBlock:ChainDbView :: forall (m :: * -> *) blk.
ChainDbView m blk
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock } StrictTVar
  m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
varCandidates
                       peer
peer StrictTVar m (AnchoredFragment (Header blk)) -> m a
body =
    (ResourceRegistry m -> m a) -> m a
forall (m :: * -> *) a.
(IOLike m, HasCallStack) =>
(ResourceRegistry m -> m a) -> m a
withRegistry ((ResourceRegistry m -> m a) -> m a)
-> (ResourceRegistry m -> m a) -> m a
forall a b. (a -> b) -> a -> b
$ \ResourceRegistry m
registry ->
      m (StrictTVar m (AnchoredFragment (Header blk)))
-> (StrictTVar m (AnchoredFragment (Header blk)) -> m ())
-> (StrictTVar m (AnchoredFragment (Header blk)) -> m a)
-> m a
forall (m :: * -> *) a b c.
MonadThrow m =>
m a -> (a -> m b) -> (a -> m c) -> m c
bracket m (StrictTVar m (AnchoredFragment (Header blk)))
register StrictTVar m (AnchoredFragment (Header blk)) -> m ()
unregister ((StrictTVar m (AnchoredFragment (Header blk)) -> m a) -> m a)
-> (StrictTVar m (AnchoredFragment (Header blk)) -> m a) -> m a
forall a b. (a -> b) -> a -> b
$ \StrictTVar m (AnchoredFragment (Header blk))
varCandidate -> do
        Tracer m (TraceChainSyncClientEvent blk)
-> ResourceRegistry m
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> STM m (AnchoredFragment (Header blk))
-> m ()
forall (m :: * -> *) blk.
(IOLike m, BlockSupportsProtocol blk,
 LedgerSupportsProtocol blk) =>
Tracer m (TraceChainSyncClientEvent blk)
-> ResourceRegistry m
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> STM m (AnchoredFragment (Header blk))
-> m ()
rejectInvalidBlocks
          Tracer m (TraceChainSyncClientEvent blk)
tracer
          ResourceRegistry m
registry
          STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock
          (StrictTVar m (AnchoredFragment (Header blk))
-> STM m (AnchoredFragment (Header blk))
forall (m :: * -> *) a. MonadSTM m => StrictTVar m a -> STM m a
readTVar StrictTVar m (AnchoredFragment (Header blk))
varCandidate)
        StrictTVar m (AnchoredFragment (Header blk)) -> m a
body StrictTVar m (AnchoredFragment (Header blk))
varCandidate
  where
    register :: m (StrictTVar m (AnchoredFragment (Header blk)))
register = do
      StrictTVar m (AnchoredFragment (Header blk))
varCandidate <- AnchoredFragment (Header blk)
-> m (StrictTVar m (AnchoredFragment (Header blk)))
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack, NoThunks a) =>
a -> m (StrictTVar m a)
newTVarIO (AnchoredFragment (Header blk)
 -> m (StrictTVar m (AnchoredFragment (Header blk))))
-> AnchoredFragment (Header blk)
-> m (StrictTVar m (AnchoredFragment (Header blk)))
forall a b. (a -> b) -> a -> b
$ Anchor (Header blk) -> AnchoredFragment (Header blk)
forall block.
HasHeader block =>
Anchor block -> AnchoredFragment block
AF.Empty Anchor (Header blk)
forall block. Anchor block
AF.AnchorGenesis
      STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar
  m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> (Map peer (StrictTVar m (AnchoredFragment (Header blk)))
    -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> STM m ()
forall (m :: * -> *) a.
MonadSTM m =>
StrictTVar m a -> (a -> a) -> STM m ()
modifyTVar StrictTVar
  m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
varCandidates ((Map peer (StrictTVar m (AnchoredFragment (Header blk)))
  -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
 -> STM m ())
-> (Map peer (StrictTVar m (AnchoredFragment (Header blk)))
    -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> STM m ()
forall a b. (a -> b) -> a -> b
$ peer
-> StrictTVar m (AnchoredFragment (Header blk))
-> Map peer (StrictTVar m (AnchoredFragment (Header blk)))
-> Map peer (StrictTVar m (AnchoredFragment (Header blk)))
forall k a. Ord k => k -> a -> Map k a -> Map k a
Map.insert peer
peer StrictTVar m (AnchoredFragment (Header blk))
varCandidate
      StrictTVar m (AnchoredFragment (Header blk))
-> m (StrictTVar m (AnchoredFragment (Header blk)))
forall (m :: * -> *) a. Monad m => a -> m a
return StrictTVar m (AnchoredFragment (Header blk))
varCandidate

    unregister :: StrictTVar m (AnchoredFragment (Header blk)) -> m ()
unregister StrictTVar m (AnchoredFragment (Header blk))
_ = do
      STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar
  m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> (Map peer (StrictTVar m (AnchoredFragment (Header blk)))
    -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> STM m ()
forall (m :: * -> *) a.
MonadSTM m =>
StrictTVar m a -> (a -> a) -> STM m ()
modifyTVar StrictTVar
  m (Map peer (StrictTVar m (AnchoredFragment (Header blk))))
varCandidates ((Map peer (StrictTVar m (AnchoredFragment (Header blk)))
  -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
 -> STM m ())
-> (Map peer (StrictTVar m (AnchoredFragment (Header blk)))
    -> Map peer (StrictTVar m (AnchoredFragment (Header blk))))
-> STM m ()
forall a b. (a -> b) -> a -> b
$ peer
-> Map peer (StrictTVar m (AnchoredFragment (Header blk)))
-> Map peer (StrictTVar m (AnchoredFragment (Header blk)))
forall k a. Ord k => k -> Map k a -> Map k a
Map.delete peer
peer

-- Our task: after connecting to an upstream node, try to maintain an
-- up-to-date header-only fragment representing their chain. We maintain
-- such candidate chains in a map with upstream nodes as keys.
--
-- The block fetch logic will use these candidate chains to download
-- blocks from, prioritising certain candidate chains over others using
-- the consensus protocol. Whenever such a block has been downloaded and
-- added to the local 'ChainDB', the 'ChainDB' will perform chain
-- selection.
--
-- We also validate the headers of a candidate chain by advancing the
-- 'ChainDepState' with the headers, which returns an error when validation
-- failed. Thus, in addition to the chain fragment of each candidate, we also
-- store a 'ChainDepState' corresponding to the head of the candidate chain.
--
-- We must keep the candidate chain synchronised with the corresponding
-- upstream chain. The upstream node's chain might roll forward or
-- backwards, and they will inform us about this. When we get these
-- messages, we will replicate these actions on our candidate chain.
--
-- INVARIANT:
--
-- >           our tip
-- >             v
-- >   /--* .... *
-- >   |
-- > --*
-- >   |
-- >   \--* .... *
-- >        fragment tip
--
-- The distance from our tip to the intersection between our chain and the
-- fragment maintained for the upstream node cannot exceed @k@ blocks. When
-- this invariant cannot be maintained, the upstream node is on a fork that
-- is too distant and we should disconnect.
--
-- TODO #423 rate-limit switching chains, otherwise we can't place blame (we
-- don't know which candidate's chain included the point that was
-- poisoned). E.g. two rollbacks per time slot -> make it configurable ->
-- just a simple argument for now.
--
-- TODO #467 if the 'theirTip' that they sent us is on our chain, just
-- switch to it.


-- = Candidate fragment size
-- -------------------------
--
-- The size of the downloaded candidate fragment ('theirFrag') and the
-- corresponding header state history ('theirHeaderStateHistory', which has the
-- same size as 'theirFrag') is limited by how far in the future the ledger view
-- can forecast.
--
-- For PBFT (Byron), we can forecast up to @2k@ slots ahead. Assuming a chain
-- density of 100%, this means the look-ahead is @2k@ headers. For mainnet this
-- means @2 * 2160 = 4320@ headers.
--
-- For TPraos (Shelley), we can forecast up to @3k/f@ slots ahead. Assuming a
-- density of @f@, this means the look-ahead is @3k@ headers. For mainnet, this
-- means @3 * 2160 = 6480@ headers.
--
-- The figure below shows the relation between 'ourFrag' and 'theirFrag':
--
-- >                       k headers or less, when A is genesis
-- >              <--------------------->
-- >            anchor    header       tip
-- >              |         |           |
-- >              V         V           V
-- > 'ourFrag':   A-H-H-H-H-H-H-H-H-...-H
-- >                     \
-- > 'theirFrag':         H-H-H-H-...   ...   ...
-- >                    ^
-- >                    |
-- >           most recent intersection (between A and the tip)
--
-- Note that the 'ourFrag' and 'theirFrag' share anchors /at all times/. In the
-- figure above, the first three headers on 'ourFrag' are thus also on
-- 'theirFrag'. The further away the most recent intersection is from the anchor
-- point, the more headers 'theirFrag' and 'ourFrag' will have in common.
--
-- In the \"worst\" case 'theirFrag' has the following length:
--
-- >                        k
-- >              <--------------------->
-- > 'ourFrag':   A-H-H-H-H-H-H-H-H-...-H
-- >                                    \
-- > 'theirFrag':                        H-H-H-H-H-H-H-H-H-H-H-H-H-H-H...-H
-- >                                     <-------------------------------->
-- >                                               max look-ahead
-- > max length   <------------------------------------------------------->
-- > of 'theirFrag'         k + max look-ahead
--
-- For PBFT this is @2160 + 4320 = 6480@ headers, for TPraos this is @2160 +
-- 6480 = 8640@ headers. The header state history will have the same length.
--
-- This worst case can happen when:
-- * We are more than 6480 or respectively 8640 blocks behind, bulk syncing, and
--   the BlockFetch client and/or the ChainDB can't keep up with the ChainSync
--   client.
-- * When our clock is running behind such that we are not adopting the
--   corresponding blocks because we think they are from the future.
-- * When an attacker is serving us headers from the future.
--
-- When we are in sync with the network, the fragment will typically be @k@ to
-- @k + 1@ headers long.

-- | State used when the intersection between the candidate and the current
-- chain is unknown.
data UnknownIntersectionState blk = UnknownIntersectionState
  { UnknownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag               :: !(AnchoredFragment (Header blk))
    -- ^ A view of the current chain fragment. Note that this might be
    -- temporarily out of date w.r.t. the actual current chain until we update
    -- it again.
    --
    -- This fragment is used to select points from to find an intersection
    -- with the candidate.
    --
    -- INVARIANT: 'ourFrag' contains @k@ headers, unless close to genesis.
  , UnknownIntersectionState blk -> HeaderStateHistory blk
ourHeaderStateHistory :: !(HeaderStateHistory blk)
    -- ^ 'HeaderStateHistory' corresponding to the tip (most recent block) of
    -- 'ourFrag'.
  , UnknownIntersectionState blk -> Our (Tip blk)
ourTip                :: !(Our (Tip blk))
    -- ^ INVARIANT: must correspond to the tip of 'ourFrag'.
  }
  deriving ((forall x.
 UnknownIntersectionState blk
 -> Rep (UnknownIntersectionState blk) x)
-> (forall x.
    Rep (UnknownIntersectionState blk) x
    -> UnknownIntersectionState blk)
-> Generic (UnknownIntersectionState blk)
forall x.
Rep (UnknownIntersectionState blk) x
-> UnknownIntersectionState blk
forall x.
UnknownIntersectionState blk
-> Rep (UnknownIntersectionState blk) x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
forall blk x.
Rep (UnknownIntersectionState blk) x
-> UnknownIntersectionState blk
forall blk x.
UnknownIntersectionState blk
-> Rep (UnknownIntersectionState blk) x
$cto :: forall blk x.
Rep (UnknownIntersectionState blk) x
-> UnknownIntersectionState blk
$cfrom :: forall blk x.
UnknownIntersectionState blk
-> Rep (UnknownIntersectionState blk) x
Generic)

instance ( LedgerSupportsProtocol blk
         ) => NoThunks (UnknownIntersectionState blk) where
  showTypeOf :: Proxy (UnknownIntersectionState blk) -> String
showTypeOf Proxy (UnknownIntersectionState blk)
_ = TypeRep -> String
forall a. Show a => a -> String
show (TypeRep -> String) -> TypeRep -> String
forall a b. (a -> b) -> a -> b
$ Proxy (UnknownIntersectionState blk) -> TypeRep
forall k (proxy :: k -> *) (a :: k).
Typeable a =>
proxy a -> TypeRep
typeRep (Proxy (UnknownIntersectionState blk)
forall k (t :: k). Proxy t
Proxy @(UnknownIntersectionState blk))

-- | State used when the intersection between the candidate and the current
-- chain is known.
data KnownIntersectionState blk = KnownIntersectionState
  { KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag               :: !(AnchoredFragment (Header blk))
    -- ^ The candidate, the synched fragment of their chain.
    --
    -- See the \"Candidate fragment size\" note above.
  , KnownIntersectionState blk -> HeaderStateHistory blk
theirHeaderStateHistory :: !(HeaderStateHistory blk)
    -- ^ 'HeaderStateHistory' corresponding to the tip (most recent block) of
    -- 'theirFrag'.
    --
    -- INVARIANT: the tips in 'theirHeaderStateHistory' correspond to the
    -- headers in 'theirFrag', including the anchor.
    --
    -- See the \"Candidate fragment size\" note above.
  , KnownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag                 :: !(AnchoredFragment (Header blk))
    -- ^ A view of the current chain fragment used to maintain the invariants
    -- with. Note that this might be temporarily out of date w.r.t. the actual
    -- current chain until we update it again.
    --
    -- INVARIANT: 'ourFrag' contains @k@ headers, unless close to genesis.
    --
    -- INVARIANT: 'theirFrag' and 'ourFrag' have the same anchor point. From
    -- this follows that both fragments intersect. This also means that
    -- 'theirFrag' forks off within the last @k@ headers/blocks of the
    -- 'ourFrag'.
  , KnownIntersectionState blk -> Our (Tip blk)
ourTip                  :: !(Our (Tip blk))
    -- ^ INVARIANT: must correspond to the tip of 'ourFrag'.
  , KnownIntersectionState blk -> Point blk
mostRecentIntersection  :: !(Point blk)
    -- ^ The most recent intersection point between 'theirFrag' and 'ourFrag'.
    -- Note that this is not necessarily the anchor point of both 'theirFrag'
    -- and 'ourFrag', they might have many more headers in common.
    --
    -- INVARIANT:
    -- > Just 'mostRecentIntersection' == 'AF.intersectionPoint' 'theirFrag' 'ourFrag'
    --
    -- It follows from the invariants on 'ourFrag' that this point is within
    -- the last @k@ headers of the current chain fragment, at time of
    -- computing the 'KnownIntersectionState'.
  }
  deriving ((forall x.
 KnownIntersectionState blk -> Rep (KnownIntersectionState blk) x)
-> (forall x.
    Rep (KnownIntersectionState blk) x -> KnownIntersectionState blk)
-> Generic (KnownIntersectionState blk)
forall x.
Rep (KnownIntersectionState blk) x -> KnownIntersectionState blk
forall x.
KnownIntersectionState blk -> Rep (KnownIntersectionState blk) x
forall a.
(forall x. a -> Rep a x) -> (forall x. Rep a x -> a) -> Generic a
forall blk x.
Rep (KnownIntersectionState blk) x -> KnownIntersectionState blk
forall blk x.
KnownIntersectionState blk -> Rep (KnownIntersectionState blk) x
$cto :: forall blk x.
Rep (KnownIntersectionState blk) x -> KnownIntersectionState blk
$cfrom :: forall blk x.
KnownIntersectionState blk -> Rep (KnownIntersectionState blk) x
Generic)

instance ( LedgerSupportsProtocol blk
         ) => NoThunks (KnownIntersectionState blk) where
  showTypeOf :: Proxy (KnownIntersectionState blk) -> String
showTypeOf Proxy (KnownIntersectionState blk)
_ = TypeRep -> String
forall a. Show a => a -> String
show (TypeRep -> String) -> TypeRep -> String
forall a b. (a -> b) -> a -> b
$ Proxy (KnownIntersectionState blk) -> TypeRep
forall k (proxy :: k -> *) (a :: k).
Typeable a =>
proxy a -> TypeRep
typeRep (Proxy (KnownIntersectionState blk)
forall k (t :: k). Proxy t
Proxy @(KnownIntersectionState blk))

checkKnownIntersectionInvariants
  :: ( HasHeader blk
     , HasHeader (Header blk)
     , HasAnnTip blk
     , ConsensusProtocol (BlockProtocol blk)
     )
  => ConsensusConfig (BlockProtocol blk)
  -> KnownIntersectionState blk
  -> Either String ()
checkKnownIntersectionInvariants :: ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> Either String ()
checkKnownIntersectionInvariants ConsensusConfig (BlockProtocol blk)
cfg KnownIntersectionState
                                     { AnchoredFragment (Header blk)
ourFrag :: AnchoredFragment (Header blk)
$sel:ourFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag
                                     , AnchoredFragment (Header blk)
theirFrag :: AnchoredFragment (Header blk)
$sel:theirFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag
                                     , HeaderStateHistory blk
theirHeaderStateHistory :: HeaderStateHistory blk
$sel:theirHeaderStateHistory:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> HeaderStateHistory blk
theirHeaderStateHistory
                                     , Our (Tip blk)
ourTip :: Our (Tip blk)
$sel:ourTip:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Our (Tip blk)
ourTip
                                     , Point blk
mostRecentIntersection :: Point blk
$sel:mostRecentIntersection:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Point blk
mostRecentIntersection
                                     }
    -- 'theirHeaderStateHistory' invariant
    | let HeaderStateHistory StrictSeq (HeaderState blk)
snapshots HeaderState blk
anchor = HeaderStateHistory blk
theirHeaderStateHistory
          historyTips :: [WithOrigin (AnnTip blk)]
historyTips  = HeaderState blk -> WithOrigin (AnnTip blk)
forall blk. HeaderState blk -> WithOrigin (AnnTip blk)
headerStateTip        (HeaderState blk -> WithOrigin (AnnTip blk))
-> [HeaderState blk] -> [WithOrigin (AnnTip blk)]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> StrictSeq (HeaderState blk) -> [HeaderState blk]
forall (t :: * -> *) a. Foldable t => t a -> [a]
Foldable.toList StrictSeq (HeaderState blk)
snapshots
          fragmentTips :: [WithOrigin (AnnTip blk)]
fragmentTips = AnnTip blk -> WithOrigin (AnnTip blk)
forall t. t -> WithOrigin t
NotOrigin (AnnTip blk -> WithOrigin (AnnTip blk))
-> (Header blk -> AnnTip blk)
-> Header blk
-> WithOrigin (AnnTip blk)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Header blk -> AnnTip blk
forall blk.
(HasHeader (Header blk), HasAnnTip blk) =>
Header blk -> AnnTip blk
getAnnTip (Header blk -> WithOrigin (AnnTip blk))
-> [Header blk] -> [WithOrigin (AnnTip blk)]
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> AnchoredFragment (Header blk) -> [Header blk]
forall block. AnchoredFragment block -> [block]
AF.toOldestFirst AnchoredFragment (Header blk)
theirFrag
          historyAnchorPoint :: Point blk
historyAnchorPoint  = WithOrigin (RealPoint blk) -> Point blk
forall blk. WithOrigin (RealPoint blk) -> Point blk
withOriginRealPointToPoint (WithOrigin (RealPoint blk) -> Point blk)
-> WithOrigin (RealPoint blk) -> Point blk
forall a b. (a -> b) -> a -> b
$ AnnTip blk -> RealPoint blk
forall blk. HasAnnTip blk => AnnTip blk -> RealPoint blk
annTipRealPoint (AnnTip blk -> RealPoint blk)
-> WithOrigin (AnnTip blk) -> WithOrigin (RealPoint blk)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> HeaderState blk -> WithOrigin (AnnTip blk)
forall blk. HeaderState blk -> WithOrigin (AnnTip blk)
headerStateTip HeaderState blk
anchor
          fragmentAnchorPoint :: Point blk
fragmentAnchorPoint = Point (Header blk) -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint (Point (Header blk) -> Point blk)
-> Point (Header blk) -> Point blk
forall a b. (a -> b) -> a -> b
$ AnchoredFragment (Header blk) -> Point (Header blk)
forall block. AnchoredFragment block -> Point block
AF.anchorPoint AnchoredFragment (Header blk)
theirFrag
    , [WithOrigin (AnnTip blk)]
historyTips [WithOrigin (AnnTip blk)] -> [WithOrigin (AnnTip blk)] -> Bool
forall a. Eq a => a -> a -> Bool
/= [WithOrigin (AnnTip blk)]
fragmentTips Bool -> Bool -> Bool
|| Point blk
historyAnchorPoint Point blk -> Point blk -> Bool
forall a. Eq a => a -> a -> Bool
/= Point blk
fragmentAnchorPoint
    = String -> Either String ()
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (String -> Either String ()) -> String -> Either String ()
forall a b. (a -> b) -> a -> b
$ Context -> String
unwords
      [ String
"The tips in theirHeaderStateHistory didn't match the headers in theirFrag:"
      , [WithOrigin (AnnTip blk)] -> String
forall a. Show a => a -> String
show [WithOrigin (AnnTip blk)]
historyTips
      , String
"vs"
      , [WithOrigin (AnnTip blk)] -> String
forall a. Show a => a -> String
show [WithOrigin (AnnTip blk)]
fragmentTips
      , String
"with anchors"
      , Point blk -> String
forall a. Show a => a -> String
show Point blk
historyAnchorPoint
      , String
"vs"
      , Point blk -> String
forall a. Show a => a -> String
show Point blk
fragmentAnchorPoint
      ]

    -- 'ourFrag' invariants
    | let nbHeaders :: Int
nbHeaders = AnchoredFragment (Header blk) -> Int
forall block. HasHeader block => AnchoredFragment block -> Int
AF.length AnchoredFragment (Header blk)
ourFrag
          ourAnchorPoint :: Point (Header blk)
ourAnchorPoint = AnchoredFragment (Header blk) -> Point (Header blk)
forall block. AnchoredFragment block -> Point block
AF.anchorPoint AnchoredFragment (Header blk)
ourFrag
    , Int
nbHeaders Int -> Int -> Bool
forall a. Ord a => a -> a -> Bool
< Word64 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral Word64
k
    , Point (Header blk)
ourAnchorPoint Point (Header blk) -> Point (Header blk) -> Bool
forall a. Eq a => a -> a -> Bool
/= Point (Header blk)
forall block. Point block
GenesisPoint
    = String -> Either String ()
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (String -> Either String ()) -> String -> Either String ()
forall a b. (a -> b) -> a -> b
$ Context -> String
unwords
      [ String
"ourFrag contains fewer than k headers and not close to genesis:"
      , Int -> String
forall a. Show a => a -> String
show Int
nbHeaders
      , String
"vs"
      , Word64 -> String
forall a. Show a => a -> String
show Word64
k
      , String
"with anchor"
      , Point (Header blk) -> String
forall a. Show a => a -> String
show Point (Header blk)
ourAnchorPoint
      ]

    | let ourFragAnchor :: Point (Header blk)
ourFragAnchor = AnchoredFragment (Header blk) -> Point (Header blk)
forall block. AnchoredFragment block -> Point block
AF.anchorPoint AnchoredFragment (Header blk)
ourFrag
          theirFragAnchor :: Point (Header blk)
theirFragAnchor = AnchoredFragment (Header blk) -> Point (Header blk)
forall block. AnchoredFragment block -> Point block
AF.anchorPoint AnchoredFragment (Header blk)
theirFrag
    , Point (Header blk)
ourFragAnchor Point (Header blk) -> Point (Header blk) -> Bool
forall a. Eq a => a -> a -> Bool
/= Point (Header blk)
theirFragAnchor
    = String -> Either String ()
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (String -> Either String ()) -> String -> Either String ()
forall a b. (a -> b) -> a -> b
$ Context -> String
unwords
      [ String
"ourFrag and theirFrag have different anchor points:"
      , Point (Header blk) -> String
forall a. Show a => a -> String
show Point (Header blk)
ourFragAnchor
      , String
"vs"
      , Point (Header blk) -> String
forall a. Show a => a -> String
show Point (Header blk)
theirFragAnchor
      ]

    -- 'ourTip' invariant
    | let ourTipPoint :: Point blk
ourTipPoint = Tip blk -> Point blk
forall b. Tip b -> Point b
getTipPoint (Our (Tip blk) -> Tip blk
forall a. Our a -> a
unOur Our (Tip blk)
ourTip)
          ourFragTipPoint :: Point blk
ourFragTipPoint = Point (Header blk) -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint (AnchoredFragment (Header blk) -> Point (Header blk)
forall block.
HasHeader block =>
AnchoredFragment block -> Point block
AF.headPoint AnchoredFragment (Header blk)
ourFrag)
    , Point blk
ourTipPoint Point blk -> Point blk -> Bool
forall a. Eq a => a -> a -> Bool
/= Point blk
ourFragTipPoint
    = String -> Either String ()
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (String -> Either String ()) -> String -> Either String ()
forall a b. (a -> b) -> a -> b
$ Context -> String
unwords
      [ String
"ourTip is not the tip of ourFrag:"
      , Point blk -> String
forall a. Show a => a -> String
show Point blk
ourTipPoint
      , String
"vs"
      , Point blk -> String
forall a. Show a => a -> String
show Point blk
ourFragTipPoint
      ]

    -- 'mostRecentIntersection' invariant
    | let actualMostRecentIntersection :: Maybe (Point blk)
actualMostRecentIntersection =
            Point (Header blk) -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint (Point (Header blk) -> Point blk)
-> Maybe (Point (Header blk)) -> Maybe (Point blk)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> AnchoredFragment (Header blk)
-> AnchoredFragment (Header blk) -> Maybe (Point (Header blk))
forall block1 block2.
(HasHeader block1, HasHeader block2,
 HeaderHash block1 ~ HeaderHash block2) =>
AnchoredFragment block1
-> AnchoredFragment block2 -> Maybe (Point block1)
AF.intersectionPoint AnchoredFragment (Header blk)
theirFrag AnchoredFragment (Header blk)
ourFrag
    , Point blk -> Maybe (Point blk)
forall a. a -> Maybe a
Just Point blk
mostRecentIntersection Maybe (Point blk) -> Maybe (Point blk) -> Bool
forall a. Eq a => a -> a -> Bool
/= Maybe (Point blk)
actualMostRecentIntersection
    = String -> Either String ()
forall e (m :: * -> *) a. MonadError e m => e -> m a
throwError (String -> Either String ()) -> String -> Either String ()
forall a b. (a -> b) -> a -> b
$ Context -> String
unwords
      [ String
"mostRecentIntersection not the most recent intersection"
      , String
"of theirFrag and ourFrag:"
      , Point blk -> String
forall a. Show a => a -> String
show Point blk
mostRecentIntersection
      , String
"vs"
      , Maybe (Point blk) -> String
forall a. Show a => a -> String
show Maybe (Point blk)
actualMostRecentIntersection
      ]

    | Bool
otherwise
    = () -> Either String ()
forall (m :: * -> *) a. Monad m => a -> m a
return ()
  where
    SecurityParam Word64
k = ConsensusConfig (BlockProtocol blk) -> SecurityParam
forall p. ConsensusProtocol p => ConsensusConfig p -> SecurityParam
protocolSecurityParam ConsensusConfig (BlockProtocol blk)
cfg

assertKnownIntersectionInvariants
  :: ( HasHeader blk
     , HasHeader (Header blk)
     , HasAnnTip blk
     , ConsensusProtocol (BlockProtocol blk)
     , HasCallStack
     )
  => ConsensusConfig (BlockProtocol blk)
  -> KnownIntersectionState blk
  -> KnownIntersectionState blk
assertKnownIntersectionInvariants :: ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
assertKnownIntersectionInvariants ConsensusConfig (BlockProtocol blk)
cfg KnownIntersectionState blk
kis =
    Either String ()
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall a. HasCallStack => Either String () -> a -> a
assertWithMsg (ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> Either String ()
forall blk.
(HasHeader blk, HasHeader (Header blk), HasAnnTip blk,
 ConsensusProtocol (BlockProtocol blk)) =>
ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> Either String ()
checkKnownIntersectionInvariants ConsensusConfig (BlockProtocol blk)
cfg KnownIntersectionState blk
kis) KnownIntersectionState blk
kis

-- | Chain sync client
--
-- This never terminates. In case of a failure, a 'ChainSyncClientException'
-- is thrown. The network layer classifies exception such that the
-- corresponding peer will never be chosen again.
chainSyncClient
    :: forall m blk.
       ( IOLike m
       , LedgerSupportsProtocol blk
       )
    => MkPipelineDecision
    -> Tracer m (TraceChainSyncClientEvent blk)
    -> TopLevelConfig blk
    -> ChainDbView m blk
    -> NodeToNodeVersion
    -> ControlMessageSTM m
    -> StrictTVar m (AnchoredFragment (Header blk))
    -> Consensus ChainSyncClientPipelined blk m
chainSyncClient :: MkPipelineDecision
-> Tracer m (TraceChainSyncClientEvent blk)
-> TopLevelConfig blk
-> ChainDbView m blk
-> NodeToNodeVersion
-> ControlMessageSTM m
-> StrictTVar m (AnchoredFragment (Header blk))
-> Consensus ChainSyncClientPipelined blk m
chainSyncClient MkPipelineDecision
mkPipelineDecision0 Tracer m (TraceChainSyncClientEvent blk)
tracer TopLevelConfig blk
cfg
                ChainDbView
                { STM m (AnchoredFragment (Header blk))
getCurrentChain :: STM m (AnchoredFragment (Header blk))
$sel:getCurrentChain:ChainDbView :: forall (m :: * -> *) blk.
ChainDbView m blk -> STM m (AnchoredFragment (Header blk))
getCurrentChain
                , STM m (HeaderStateHistory blk)
getHeaderStateHistory :: STM m (HeaderStateHistory blk)
$sel:getHeaderStateHistory:ChainDbView :: forall (m :: * -> *) blk.
ChainDbView m blk -> STM m (HeaderStateHistory blk)
getHeaderStateHistory
                , Point blk -> STM m (Maybe (ExtLedgerState blk))
getPastLedger :: Point blk -> STM m (Maybe (ExtLedgerState blk))
$sel:getPastLedger:ChainDbView :: forall (m :: * -> *) blk.
ChainDbView m blk
-> Point blk -> STM m (Maybe (ExtLedgerState blk))
getPastLedger
                , STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock :: STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
$sel:getIsInvalidBlock:ChainDbView :: forall (m :: * -> *) blk.
ChainDbView m blk
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock
                }
                NodeToNodeVersion
_version
                ControlMessageSTM m
controlMessageSTM
                StrictTVar m (AnchoredFragment (Header blk))
varCandidate = m (ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> Consensus ChainSyncClientPipelined blk m
forall header point tip (m :: * -> *) a.
m (ClientPipelinedStIdle 'Z header point tip m a)
-> ChainSyncClientPipelined header point tip m a
ChainSyncClientPipelined (m (ClientPipelinedStIdle
      'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
 -> Consensus ChainSyncClientPipelined blk m)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> Consensus ChainSyncClientPipelined blk m
forall a b. (a -> b) -> a -> b
$
    ()
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState () (Stateful m blk () (ClientPipelinedStIdle 'Z)
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ Stateful m blk () (ClientPipelinedStIdle 'Z)
initialise
  where
    -- | Start ChainSync by looking for an intersection between our current
    -- chain fragment and their chain.
    initialise :: Stateful m blk () (ClientPipelinedStIdle 'Z)
    initialise :: Stateful m blk () (ClientPipelinedStIdle 'Z)
initialise = (Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult)
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
findIntersection (Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
forall blk.
BlockSupportsProtocol blk =>
Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
ForkTooDeep Point blk
forall block. Point block
GenesisPoint)

    -- | Try to find an intersection by sending points of our current chain to
    -- the server, if any of them intersect with their chain, roll back our
    -- chain to that point and start synching using that fragment. If none
    -- intersect, disconnect by throwing the exception obtained by calling the
    -- passed function.
    findIntersection
      :: (Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult)
         -- ^ Exception to throw when no intersection is found.
      -> Stateful m blk () (ClientPipelinedStIdle 'Z)
    findIntersection :: (Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult)
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
findIntersection Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
mkResult = (()
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((()
  -> m (ClientPipelinedStIdle
          'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
 -> Stateful m blk () (ClientPipelinedStIdle 'Z))
-> (()
    -> m (ClientPipelinedStIdle
            'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
forall a b. (a -> b) -> a -> b
$ \() -> do
      (AnchoredFragment (Header blk)
ourFrag, HeaderStateHistory blk
ourHeaderStateHistory) <- STM m (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m (AnchoredFragment (Header blk), HeaderStateHistory blk)
 -> m (AnchoredFragment (Header blk), HeaderStateHistory blk))
-> STM m (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall a b. (a -> b) -> a -> b
$ (,)
        (AnchoredFragment (Header blk)
 -> HeaderStateHistory blk
 -> (AnchoredFragment (Header blk), HeaderStateHistory blk))
-> STM m (AnchoredFragment (Header blk))
-> STM
     m
     (HeaderStateHistory blk
      -> (AnchoredFragment (Header blk), HeaderStateHistory blk))
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> STM m (AnchoredFragment (Header blk))
getCurrentChain
        STM
  m
  (HeaderStateHistory blk
   -> (AnchoredFragment (Header blk), HeaderStateHistory blk))
-> STM m (HeaderStateHistory blk)
-> STM m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall (f :: * -> *) a b. Applicative f => f (a -> b) -> f a -> f b
<*> STM m (HeaderStateHistory blk)
getHeaderStateHistory
      -- We select points from the last @k@ headers of our current chain. This
      -- means that if an intersection is found for one of these points, it
      -- was an intersection within the last @k@ blocks of our current chain.
      -- If not, we could never switch to this candidate chain anyway.
      let maxOffset :: Word64
maxOffset = Int -> Word64
forall a b. (Integral a, Num b) => a -> b
fromIntegral (AnchoredFragment (Header blk) -> Int
forall block. HasHeader block => AnchoredFragment block -> Int
AF.length AnchoredFragment (Header blk)
ourFrag)
          points :: [Point blk]
points    = (Point (Header blk) -> Point blk)
-> [Point (Header blk)] -> [Point blk]
forall a b. (a -> b) -> [a] -> [b]
map Point (Header blk) -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint
                    ([Point (Header blk)] -> [Point blk])
-> [Point (Header blk)] -> [Point blk]
forall a b. (a -> b) -> a -> b
$ [Int] -> AnchoredFragment (Header blk) -> [Point (Header blk)]
forall block.
HasHeader block =>
[Int] -> AnchoredFragment block -> [Point block]
AF.selectPoints
                        ((Word64 -> Int) -> [Word64] -> [Int]
forall a b. (a -> b) -> [a] -> [b]
map Word64 -> Int
forall a b. (Integral a, Num b) => a -> b
fromIntegral (Word64 -> [Word64]
offsets Word64
maxOffset))
                        AnchoredFragment (Header blk)
ourFrag
          ourTip :: Our (Tip blk)
ourTip    = AnchoredFragment (Header blk) -> Our (Tip blk)
ourTipFromChain AnchoredFragment (Header blk)
ourFrag
          uis :: UnknownIntersectionState blk
uis = UnknownIntersectionState :: forall blk.
AnchoredFragment (Header blk)
-> HeaderStateHistory blk
-> Our (Tip blk)
-> UnknownIntersectionState blk
UnknownIntersectionState {
              $sel:ourFrag:UnknownIntersectionState :: AnchoredFragment (Header blk)
ourFrag               = AnchoredFragment (Header blk)
ourFrag
            , $sel:ourHeaderStateHistory:UnknownIntersectionState :: HeaderStateHistory blk
ourHeaderStateHistory = HeaderStateHistory blk
ourHeaderStateHistory
            , $sel:ourTip:UnknownIntersectionState :: Our (Tip blk)
ourTip                = Our (Tip blk)
ourTip
            }
      ClientPipelinedStIdle
  'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) a. Monad m => a -> m a
return (ClientPipelinedStIdle
   'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ [Point blk]
-> ClientPipelinedStIntersect
     (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall point header tip (m :: * -> *) a.
[point]
-> ClientPipelinedStIntersect header point tip m a
-> ClientPipelinedStIdle 'Z header point tip m a
SendMsgFindIntersect [Point blk]
points (ClientPipelinedStIntersect
   (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> ClientPipelinedStIdle
      'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientPipelinedStIntersect
     (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall a b. (a -> b) -> a -> b
$ ClientPipelinedStIntersect :: forall header point tip (m :: * -> *) a.
(point -> tip -> m (ClientPipelinedStIdle 'Z header point tip m a))
-> (tip -> m (ClientPipelinedStIdle 'Z header point tip m a))
-> ClientPipelinedStIntersect header point tip m a
ClientPipelinedStIntersect
        { recvMsgIntersectFound :: Point blk
-> Tip blk
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgIntersectFound = \Point blk
i Tip blk
theirTip' ->
            UnknownIntersectionState blk
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState UnknownIntersectionState blk
uis (Stateful
   m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$
              Point blk
-> Their (Tip blk)
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
intersectFound (Point blk -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point blk
i) (Tip blk -> Their (Tip blk)
forall a. a -> Their a
Their Tip blk
theirTip')
        , recvMsgIntersectNotFound :: Tip blk
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgIntersectNotFound = \Tip blk
theirTip' ->
            ClientPipelinedStIdle
  'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) a. Monad m => a -> m a
return (ClientPipelinedStIdle
   'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
terminate (ChainSyncClientResult
 -> ClientPipelinedStIdle
      'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall a b. (a -> b) -> a -> b
$ Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
mkResult Our (Tip blk)
ourTip (Tip blk -> Their (Tip blk)
forall a. a -> Their a
Their Tip blk
theirTip')
        }

    -- | One of the points we sent intersected our chain. This intersection
    -- point will become the new tip of the candidate chain.
    intersectFound :: Point blk  -- ^ Intersection
                   -> Their (Tip blk)
                   -> Stateful m blk
                        (UnknownIntersectionState blk)
                        (ClientPipelinedStIdle 'Z)
    intersectFound :: Point blk
-> Their (Tip blk)
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
intersectFound Point blk
intersection Their (Tip blk)
theirTip
                 = (UnknownIntersectionState blk
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((UnknownIntersectionState blk
  -> m (ClientPipelinedStIdle
          'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
 -> Stateful
      m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z))
-> (UnknownIntersectionState blk
    -> m (ClientPipelinedStIdle
            'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (UnknownIntersectionState blk) (ClientPipelinedStIdle 'Z)
forall a b. (a -> b) -> a -> b
$ \UnknownIntersectionState
                     { AnchoredFragment (Header blk)
ourFrag :: AnchoredFragment (Header blk)
$sel:ourFrag:UnknownIntersectionState :: forall blk.
UnknownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag
                     , HeaderStateHistory blk
ourHeaderStateHistory :: HeaderStateHistory blk
$sel:ourHeaderStateHistory:UnknownIntersectionState :: forall blk. UnknownIntersectionState blk -> HeaderStateHistory blk
ourHeaderStateHistory
                     , $sel:ourTip:UnknownIntersectionState :: forall blk. UnknownIntersectionState blk -> Our (Tip blk)
ourTip = Our (Tip blk)
ourTip
                     } -> do
      Tracer m (TraceChainSyncClientEvent blk)
-> TraceChainSyncClientEvent blk -> m ()
forall (m :: * -> *) a. Tracer m a -> a -> m ()
traceWith Tracer m (TraceChainSyncClientEvent blk)
tracer (TraceChainSyncClientEvent blk -> m ())
-> TraceChainSyncClientEvent blk -> m ()
forall a b. (a -> b) -> a -> b
$ Point blk
-> Our (Tip blk)
-> Their (Tip blk)
-> TraceChainSyncClientEvent blk
forall blk.
Point blk
-> Our (Tip blk)
-> Their (Tip blk)
-> TraceChainSyncClientEvent blk
TraceFoundIntersection Point blk
intersection Our (Tip blk)
ourTip Their (Tip blk)
theirTip
      m (ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a. m a -> m a
traceException (m (ClientPipelinedStIdle
      'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ do
        -- Roll back the current chain fragment to the @intersection@.
        --
        -- While the primitives in the ChainSync protocol are "roll back",
        -- "roll forward (apply block)", etc. The /real/ primitive is "switch
        -- to fork", which means that a roll back is always followed by
        -- applying at least as many blocks that we rolled back.
        --
        -- This is important for 'rewindHeaderStateHistory', which can only roll
        -- back up to @k@ blocks, /once/, i.e., we cannot keep rolling back the
        -- same chain state multiple times, because that would mean that we
        -- store the chain state for the /whole chain/, all the way to genesis.
        --
        -- So the rewind below is fine when we are switching to a fork (i.e.
        -- it is followed by rolling forward again), but we need some
        -- guarantees that the ChainSync protocol /does/ in fact give us a
        -- switch-to-fork instead of a true rollback.
        (AnchoredFragment (Header blk)
theirFrag, HeaderStateHistory blk
theirHeaderStateHistory) <- do
          case Point blk
-> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall blk.
(BlockSupportsProtocol blk, HasAnnTip blk) =>
Point blk
-> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
attemptRollback Point blk
intersection (AnchoredFragment (Header blk)
ourFrag, HeaderStateHistory blk
ourHeaderStateHistory) of
            Just (AnchoredFragment (Header blk)
c, HeaderStateHistory blk
d) -> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall (m :: * -> *) a. Monad m => a -> m a
return (AnchoredFragment (Header blk)
c, HeaderStateHistory blk
d)
            -- The @intersection@ is not on the candidate chain, even though
            -- we sent only points from the candidate chain to find an
            -- intersection with. The node must have sent us an invalid
            -- intersection point.
            Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
Nothing     -> ChainSyncClientException
-> m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall (m' :: * -> *) x'.
MonadThrow m' =>
ChainSyncClientException -> m' x'
disconnect (ChainSyncClientException
 -> m (AnchoredFragment (Header blk), HeaderStateHistory blk))
-> ChainSyncClientException
-> m (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall a b. (a -> b) -> a -> b
$
              Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientException
forall blk.
BlockSupportsProtocol blk =>
Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientException
InvalidIntersection Point blk
intersection Our (Tip blk)
ourTip Their (Tip blk)
theirTip
        STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar m (AnchoredFragment (Header blk))
-> AnchoredFragment (Header blk) -> STM m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
StrictTVar m a -> a -> STM m ()
writeTVar StrictTVar m (AnchoredFragment (Header blk))
varCandidate AnchoredFragment (Header blk)
theirFrag
        let kis :: KnownIntersectionState blk
kis = ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall blk.
(HasHeader blk, HasHeader (Header blk), HasAnnTip blk,
 ConsensusProtocol (BlockProtocol blk), HasCallStack) =>
ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
assertKnownIntersectionInvariants (TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
forall blk.
TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
configConsensus TopLevelConfig blk
cfg) (KnownIntersectionState blk -> KnownIntersectionState blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall a b. (a -> b) -> a -> b
$
              KnownIntersectionState :: forall blk.
AnchoredFragment (Header blk)
-> HeaderStateHistory blk
-> AnchoredFragment (Header blk)
-> Our (Tip blk)
-> Point blk
-> KnownIntersectionState blk
KnownIntersectionState
                { $sel:theirFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
theirFrag               = AnchoredFragment (Header blk)
theirFrag
                , $sel:theirHeaderStateHistory:KnownIntersectionState :: HeaderStateHistory blk
theirHeaderStateHistory = HeaderStateHistory blk
theirHeaderStateHistory
                , $sel:ourFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
ourFrag                 = AnchoredFragment (Header blk)
ourFrag
                , $sel:ourTip:KnownIntersectionState :: Our (Tip blk)
ourTip                  = Our (Tip blk)
ourTip
                , $sel:mostRecentIntersection:KnownIntersectionState :: Point blk
mostRecentIntersection  = Point blk
intersection
                }
        KnownIntersectionState blk
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState KnownIntersectionState blk
kis (Stateful
   m blk (KnownIntersectionState blk) (ClientPipelinedStIdle 'Z)
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ MkPipelineDecision
-> Nat 'Z
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle 'Z)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
nextStep MkPipelineDecision
mkPipelineDecision0 Nat 'Z
forall (n :: N). ('Z ~ n) => Nat n
Zero Their (Tip blk)
theirTip

    -- | Look at the current chain fragment that may have been updated in the
    -- background. Check whether the candidate fragment still intersects with
    -- it. If so, update the 'KnownIntersectionState' and trim the candidate
    -- fragment to the new current chain fragment's anchor point. If not,
    -- return 'Nothing'.
    intersectsWithCurrentChain
      :: KnownIntersectionState blk
      -> STM m (Maybe (KnownIntersectionState blk))
    intersectsWithCurrentChain :: KnownIntersectionState blk
-> STM m (Maybe (KnownIntersectionState blk))
intersectsWithCurrentChain kis :: KnownIntersectionState blk
kis@KnownIntersectionState
                               { AnchoredFragment (Header blk)
theirFrag :: AnchoredFragment (Header blk)
$sel:theirFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag
                               , HeaderStateHistory blk
theirHeaderStateHistory :: HeaderStateHistory blk
$sel:theirHeaderStateHistory:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> HeaderStateHistory blk
theirHeaderStateHistory
                               , AnchoredFragment (Header blk)
ourFrag :: AnchoredFragment (Header blk)
$sel:ourFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag
                               } = do
      AnchoredFragment (Header blk)
ourFrag' <- STM m (AnchoredFragment (Header blk))
getCurrentChain
      if
        | AnchoredFragment (Header blk) -> Point (Header blk)
forall block.
HasHeader block =>
AnchoredFragment block -> Point block
AF.headPoint AnchoredFragment (Header blk)
ourFrag Point (Header blk) -> Point (Header blk) -> Bool
forall a. Eq a => a -> a -> Bool
== AnchoredFragment (Header blk) -> Point (Header blk)
forall block.
HasHeader block =>
AnchoredFragment block -> Point block
AF.headPoint AnchoredFragment (Header blk)
ourFrag' ->
          -- Our current chain didn't change, and changes to their chain that
          -- might affect the intersection point are handled elsewhere
          -- ('rollBackward'), so we have nothing to do.
          Maybe (KnownIntersectionState blk)
-> STM m (Maybe (KnownIntersectionState blk))
forall (m :: * -> *) a. Monad m => a -> m a
return (Maybe (KnownIntersectionState blk)
 -> STM m (Maybe (KnownIntersectionState blk)))
-> Maybe (KnownIntersectionState blk)
-> STM m (Maybe (KnownIntersectionState blk))
forall a b. (a -> b) -> a -> b
$ KnownIntersectionState blk -> Maybe (KnownIntersectionState blk)
forall a. a -> Maybe a
Just KnownIntersectionState blk
kis

        | Just Point (Header blk)
intersection <- AnchoredFragment (Header blk)
-> AnchoredFragment (Header blk) -> Maybe (Point (Header blk))
forall block1 block2.
(HasHeader block1, HasHeader block2,
 HeaderHash block1 ~ HeaderHash block2) =>
AnchoredFragment block1
-> AnchoredFragment block2 -> Maybe (Point block1)
AF.intersectionPoint AnchoredFragment (Header blk)
ourFrag' AnchoredFragment (Header blk)
theirFrag ->
          -- Our current chain changed, but it still intersects with candidate
          -- fragment, so update the 'ourFrag' field and trim to the
          -- candidate fragment to the same anchor point.
          --
          -- Note that this is the only place we need to trim. Headers on
          -- their chain can only become unnecessary (eligible for trimming)
          -- in two ways: 1. we adopted them, i.e., our chain changed (handled
          -- in this function); 2. we will /never/ adopt them, which is
          -- handled in the "no more intersection case".
          case AnchoredFragment (Header blk)
-> Point (Header blk)
-> Maybe
     (AnchoredFragment (Header blk), AnchoredFragment (Header blk))
forall block1 block2.
(HasHeader block1, HeaderHash block1 ~ HeaderHash block2) =>
AnchoredFragment block1
-> Point block2
-> Maybe (AnchoredFragment block1, AnchoredFragment block1)
AF.splitAfterPoint AnchoredFragment (Header blk)
theirFrag (AnchoredFragment (Header blk) -> Point (Header blk)
forall block. AnchoredFragment block -> Point block
AF.anchorPoint AnchoredFragment (Header blk)
ourFrag') of
           -- + Before the update to our fragment, both fragments were
           --   anchored at the same anchor.
           -- + We still have an intersection.
           -- + The number of blocks after the intersection cannot have
           --   shrunk, but could have increased.
           -- + If it did increase, the anchor point will have shifted up.
           -- + It can't have moved up past the intersection point (because
           --   then there would be no intersection anymore).
           -- + This means the new anchor point must be between the old anchor
           --   point and the new intersection point.
           -- + Since we know both the old anchor point and the new
           --   intersection point exist on their fragment, the new anchor
           --   point must also.
           Maybe
  (AnchoredFragment (Header blk), AnchoredFragment (Header blk))
Nothing -> String -> STM m (Maybe (KnownIntersectionState blk))
forall a. HasCallStack => String -> a
error
               String
"anchor point must be on candidate fragment if they intersect"
           Just (AnchoredFragment (Header blk)
_, AnchoredFragment (Header blk)
trimmedCandidateFrag) -> Maybe (KnownIntersectionState blk)
-> STM m (Maybe (KnownIntersectionState blk))
forall (m :: * -> *) a. Monad m => a -> m a
return (Maybe (KnownIntersectionState blk)
 -> STM m (Maybe (KnownIntersectionState blk)))
-> Maybe (KnownIntersectionState blk)
-> STM m (Maybe (KnownIntersectionState blk))
forall a b. (a -> b) -> a -> b
$ KnownIntersectionState blk -> Maybe (KnownIntersectionState blk)
forall a. a -> Maybe a
Just (KnownIntersectionState blk -> Maybe (KnownIntersectionState blk))
-> KnownIntersectionState blk -> Maybe (KnownIntersectionState blk)
forall a b. (a -> b) -> a -> b
$
               ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall blk.
(HasHeader blk, HasHeader (Header blk), HasAnnTip blk,
 ConsensusProtocol (BlockProtocol blk), HasCallStack) =>
ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
assertKnownIntersectionInvariants (TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
forall blk.
TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
configConsensus TopLevelConfig blk
cfg) (KnownIntersectionState blk -> KnownIntersectionState blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall a b. (a -> b) -> a -> b
$
                 KnownIntersectionState :: forall blk.
AnchoredFragment (Header blk)
-> HeaderStateHistory blk
-> AnchoredFragment (Header blk)
-> Our (Tip blk)
-> Point blk
-> KnownIntersectionState blk
KnownIntersectionState {
                     $sel:ourFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
ourFrag                 = AnchoredFragment (Header blk)
ourFrag'
                   , $sel:theirFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
theirFrag               = AnchoredFragment (Header blk)
trimmedCandidateFrag
                   , $sel:theirHeaderStateHistory:KnownIntersectionState :: HeaderStateHistory blk
theirHeaderStateHistory = HeaderStateHistory blk
trimmedHeaderStateHistory'
                   , $sel:ourTip:KnownIntersectionState :: Our (Tip blk)
ourTip                  = AnchoredFragment (Header blk) -> Our (Tip blk)
ourTipFromChain AnchoredFragment (Header blk)
ourFrag'
                   , $sel:mostRecentIntersection:KnownIntersectionState :: Point blk
mostRecentIntersection  = Point (Header blk) -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point (Header blk)
intersection
                   }
             where
               -- We trim the 'HeaderStateHistory' to the same size as our
               -- fragment so they keep in sync.
               trimmedHeaderStateHistory' :: HeaderStateHistory blk
trimmedHeaderStateHistory' =
                 Int -> HeaderStateHistory blk -> HeaderStateHistory blk
forall blk. Int -> HeaderStateHistory blk -> HeaderStateHistory blk
HeaderStateHistory.trim
                   (AnchoredFragment (Header blk) -> Int
forall block. HasHeader block => AnchoredFragment block -> Int
AF.length AnchoredFragment (Header blk)
trimmedCandidateFrag)
                   HeaderStateHistory blk
theirHeaderStateHistory

        | Bool
otherwise ->
          -- No more intersection with the current chain
          Maybe (KnownIntersectionState blk)
-> STM m (Maybe (KnownIntersectionState blk))
forall (m :: * -> *) a. Monad m => a -> m a
return Maybe (KnownIntersectionState blk)
forall a. Maybe a
Nothing

    -- | Request the next message (roll forward or backward), unless our chain
    -- has changed such that it no longer intersects with the candidate, in
    -- which case we initiate the intersection finding part of the protocol.
    --
    -- This is the main place we check whether our current chain has changed.
    -- We also check it in 'rollForward' to make sure we have an up-to-date
    -- intersection before calling 'getLedgerView'.
    --
    -- This is also the place where we checked whether we're asked to terminate
    -- by the mux layer.
    nextStep :: MkPipelineDecision
             -> Nat n
             -> Their (Tip blk)
             -> Stateful m blk
                  (KnownIntersectionState blk)
                  (ClientPipelinedStIdle n)
    nextStep :: MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
nextStep MkPipelineDecision
mkPipelineDecision Nat n
n Their (Tip blk)
theirTip = (KnownIntersectionState blk
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((KnownIntersectionState blk
  -> m (Consensus (ClientPipelinedStIdle n) blk m))
 -> Stateful
      m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n))
-> (KnownIntersectionState blk
    -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ \KnownIntersectionState blk
kis -> do
      ControlMessageSTM m -> m ControlMessage
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically ControlMessageSTM m
controlMessageSTM m ControlMessage
-> (ControlMessage
    -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) a b. Monad m => m a -> (a -> m b) -> m b
>>= \case
        -- We have been asked to terminate the client
        ControlMessage
Terminate ->
          Nat n
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (n :: N).
Nat n
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
terminateAfterDrain Nat n
n (ChainSyncClientResult
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ ChainSyncClientResult
AskedToTerminate
        ControlMessage
_continue -> do
          Maybe (KnownIntersectionState blk)
mKis' <- STM m (Maybe (KnownIntersectionState blk))
-> m (Maybe (KnownIntersectionState blk))
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m (Maybe (KnownIntersectionState blk))
 -> m (Maybe (KnownIntersectionState blk)))
-> STM m (Maybe (KnownIntersectionState blk))
-> m (Maybe (KnownIntersectionState blk))
forall a b. (a -> b) -> a -> b
$ KnownIntersectionState blk
-> STM m (Maybe (KnownIntersectionState blk))
intersectsWithCurrentChain KnownIntersectionState blk
kis
          case Maybe (KnownIntersectionState blk)
mKis' of
            Just kis' :: KnownIntersectionState blk
kis'@KnownIntersectionState { AnchoredFragment (Header blk)
theirFrag :: AnchoredFragment (Header blk)
$sel:theirFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag } -> do
              -- Our chain (tip) didn't change or if it did, it still intersects
              -- with the candidate fragment, so we can continue requesting the
              -- next block.
              STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar m (AnchoredFragment (Header blk))
-> AnchoredFragment (Header blk) -> STM m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
StrictTVar m a -> a -> STM m ()
writeTVar StrictTVar m (AnchoredFragment (Header blk))
varCandidate AnchoredFragment (Header blk)
theirFrag
              let candTipBlockNo :: WithOrigin BlockNo
candTipBlockNo = AnchoredFragment (Header blk) -> WithOrigin BlockNo
forall block.
HasHeader block =>
AnchoredFragment block -> WithOrigin BlockNo
AF.headBlockNo AnchoredFragment (Header blk)
theirFrag
              Consensus (ClientPipelinedStIdle n) blk m
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) a. Monad m => a -> m a
return (Consensus (ClientPipelinedStIdle n) blk m
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Consensus (ClientPipelinedStIdle n) blk m
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$
                KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> WithOrigin BlockNo
-> Consensus (ClientPipelinedStIdle n) blk m
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> WithOrigin BlockNo
-> Consensus (ClientPipelinedStIdle n) blk m
requestNext KnownIntersectionState blk
kis' MkPipelineDecision
mkPipelineDecision Nat n
n Their (Tip blk)
theirTip WithOrigin BlockNo
candTipBlockNo
            Maybe (KnownIntersectionState blk)
Nothing ->
              -- Our chain (tip) has changed and it no longer intersects with
              -- the candidate fragment, so we have to find a new intersection,
              -- but first drain the pipe.
              ()
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState ()
                (Stateful m blk () (ClientPipelinedStIdle n)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ Nat n
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall s (n :: N).
NoThunks s =>
Nat n
-> Stateful m blk s (ClientPipelinedStIdle 'Z)
-> Stateful m blk s (ClientPipelinedStIdle n)
drainThePipe Nat n
n
                (Stateful m blk () (ClientPipelinedStIdle 'Z)
 -> Stateful m blk () (ClientPipelinedStIdle n))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ (Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult)
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
findIntersection Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
forall blk.
BlockSupportsProtocol blk =>
Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
NoMoreIntersection

    -- | "Drain the pipe": collect and discard all in-flight responses and
    -- finally execute the given action.
    drainThePipe :: forall s n. NoThunks s
                 => Nat n
                 -> Stateful m blk s (ClientPipelinedStIdle 'Z)
                 -> Stateful m blk s (ClientPipelinedStIdle n)
    drainThePipe :: Nat n
-> Stateful m blk s (ClientPipelinedStIdle 'Z)
-> Stateful m blk s (ClientPipelinedStIdle n)
drainThePipe Nat n
n0 Stateful m blk s (ClientPipelinedStIdle 'Z)
m = (s -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful m blk s (ClientPipelinedStIdle n)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((s -> m (Consensus (ClientPipelinedStIdle n) blk m))
 -> Stateful m blk s (ClientPipelinedStIdle n))
-> (s -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful m blk s (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ Nat n -> s -> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (n' :: N).
Nat n' -> s -> m (Consensus (ClientPipelinedStIdle n') blk m)
go Nat n
n0
      where
        go :: forall n'. Nat n'
           -> s
           -> m (Consensus (ClientPipelinedStIdle n') blk m)
        go :: Nat n' -> s -> m (Consensus (ClientPipelinedStIdle n') blk m)
go Nat n'
n s
s = case Nat n'
n of
          Nat n'
Zero    -> s
-> Stateful m blk s (ClientPipelinedStIdle 'Z)
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState s
s Stateful m blk s (ClientPipelinedStIdle 'Z)
m
          Succ Nat n
n' -> ClientPipelinedStIdle
  ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) a. Monad m => a -> m a
return (ClientPipelinedStIdle
   ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> m (ClientPipelinedStIdle
         ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ Maybe
  (ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n1 :: N) header point tip (m :: * -> *) a.
Maybe (ClientPipelinedStIdle ('S n1) header point tip m a)
-> ClientStNext n1 header point tip m a
-> ClientPipelinedStIdle ('S n1) header point tip m a
CollectResponse Maybe
  (ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a. Maybe a
Nothing (ClientStNext
   n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> ClientPipelinedStIdle
      ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall a b. (a -> b) -> a -> b
$ ClientStNext :: forall (n :: N) header point tip (m :: * -> *) a.
(header -> tip -> m (ClientPipelinedStIdle n header point tip m a))
-> (point
    -> tip -> m (ClientPipelinedStIdle n header point tip m a))
-> ClientStNext n header point tip m a
ClientStNext
            { recvMsgRollForward :: Header blk
-> Tip blk
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgRollForward  = \Header blk
_hdr Tip blk
_tip -> Nat n
-> s
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (n' :: N).
Nat n' -> s -> m (Consensus (ClientPipelinedStIdle n') blk m)
go Nat n
n' s
s
            , recvMsgRollBackward :: Point blk
-> Tip blk
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgRollBackward = \Point blk
_pt  Tip blk
_tip -> Nat n
-> s
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (n' :: N).
Nat n' -> s -> m (Consensus (ClientPipelinedStIdle n') blk m)
go Nat n
n' s
s
            }

    requestNext :: KnownIntersectionState blk
                -> MkPipelineDecision
                -> Nat n
                -> Their (Tip blk)
                -> WithOrigin BlockNo
                -> Consensus (ClientPipelinedStIdle n) blk m
    requestNext :: KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> WithOrigin BlockNo
-> Consensus (ClientPipelinedStIdle n) blk m
requestNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision Nat n
n Their (Tip blk)
theirTip WithOrigin BlockNo
candTipBlockNo =
        case (Nat n
n, (PipelineDecision n, MkPipelineDecision)
decision) of
          (Nat n
Zero, (PipelineDecision n
Request, MkPipelineDecision
mkPipelineDecision')) ->
            ClientStNext
  'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientStNext
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall header point tip (m :: * -> *) a.
ClientStNext 'Z header point tip m a
-> m (ClientStNext 'Z header point tip m a)
-> ClientPipelinedStIdle 'Z header point tip m a
SendMsgRequestNext
              (KnownIntersectionState blk
-> MkPipelineDecision
-> Nat 'Z
-> ClientStNext
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision -> Nat n -> Consensus (ClientStNext n) blk m
handleNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' Nat 'Z
forall (n :: N). ('Z ~ n) => Nat n
Zero)
              (ClientStNext
  'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientStNext
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) a. Monad m => a -> m a
return (ClientStNext
   'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> m (ClientStNext
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientStNext
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientStNext
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ KnownIntersectionState blk
-> MkPipelineDecision
-> Nat 'Z
-> ClientStNext
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision -> Nat n -> Consensus (ClientStNext n) blk m
handleNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' Nat 'Z
forall (n :: N). ('Z ~ n) => Nat n
Zero) -- when we have to wait
          (Nat n
_, (PipelineDecision n
Pipeline, MkPipelineDecision
mkPipelineDecision')) ->
            ClientPipelinedStIdle
  ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> Consensus (ClientPipelinedStIdle n) blk m
forall (n :: N) header point tip (m :: * -> *) a.
ClientPipelinedStIdle ('S n) header point tip m a
-> ClientPipelinedStIdle n header point tip m a
SendMsgRequestNextPipelined
              (KnownIntersectionState blk
-> MkPipelineDecision
-> Nat ('S n)
-> Their (Tip blk)
-> WithOrigin BlockNo
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> WithOrigin BlockNo
-> Consensus (ClientPipelinedStIdle n) blk m
requestNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' (Nat n -> Nat ('S n)
forall (m :: N) (n :: N). (m ~ 'S n) => Nat n -> Nat m
Succ Nat n
n) Their (Tip blk)
theirTip WithOrigin BlockNo
candTipBlockNo)
          (Succ Nat n
n', (PipelineDecision n
CollectOrPipeline, MkPipelineDecision
mkPipelineDecision')) ->
            Maybe
  (ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n1 :: N) header point tip (m :: * -> *) a.
Maybe (ClientPipelinedStIdle ('S n1) header point tip m a)
-> ClientStNext n1 header point tip m a
-> ClientPipelinedStIdle ('S n1) header point tip m a
CollectResponse
              (ClientPipelinedStIdle
  ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> Maybe
     (ClientPipelinedStIdle
        ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a. a -> Maybe a
Just (ClientPipelinedStIdle
   ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> Maybe
      (ClientPipelinedStIdle
         ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> Maybe
     (ClientPipelinedStIdle
        ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ ClientPipelinedStIdle
  ('S ('S n))
  (Header blk)
  (Point blk)
  (Tip blk)
  m
  ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N) header point tip (m :: * -> *) a.
ClientPipelinedStIdle ('S n) header point tip m a
-> ClientPipelinedStIdle n header point tip m a
SendMsgRequestNextPipelined (ClientPipelinedStIdle
   ('S ('S n))
   (Header blk)
   (Point blk)
   (Tip blk)
   m
   ChainSyncClientResult
 -> ClientPipelinedStIdle
      ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientPipelinedStIdle
     ('S ('S n))
     (Header blk)
     (Point blk)
     (Tip blk)
     m
     ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall a b. (a -> b) -> a -> b
$
                KnownIntersectionState blk
-> MkPipelineDecision
-> Nat ('S ('S n))
-> Their (Tip blk)
-> WithOrigin BlockNo
-> ClientPipelinedStIdle
     ('S ('S n))
     (Header blk)
     (Point blk)
     (Tip blk)
     m
     ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> WithOrigin BlockNo
-> Consensus (ClientPipelinedStIdle n) blk m
requestNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' (Nat n -> Nat ('S ('S n))
forall (m :: N) (n :: N). (m ~ 'S n) => Nat n -> Nat m
Succ Nat n
n) Their (Tip blk)
theirTip WithOrigin BlockNo
candTipBlockNo)
              (KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision -> Nat n -> Consensus (ClientStNext n) blk m
handleNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' Nat n
n')
          (Succ Nat n
n', (PipelineDecision n
Collect, MkPipelineDecision
mkPipelineDecision')) ->
            Maybe
  (ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n1 :: N) header point tip (m :: * -> *) a.
Maybe (ClientPipelinedStIdle ('S n1) header point tip m a)
-> ClientStNext n1 header point tip m a
-> ClientPipelinedStIdle ('S n1) header point tip m a
CollectResponse
              Maybe
  (ClientPipelinedStIdle
     ('S n) (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a. Maybe a
Nothing
              (KnownIntersectionState blk
-> MkPipelineDecision
-> Nat n
-> ClientStNext
     n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall (n :: N).
KnownIntersectionState blk
-> MkPipelineDecision -> Nat n -> Consensus (ClientStNext n) blk m
handleNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision' Nat n
n')
      where
        theirTipBlockNo :: WithOrigin BlockNo
theirTipBlockNo = Tip blk -> WithOrigin BlockNo
forall b. Tip b -> WithOrigin BlockNo
getTipBlockNo (Their (Tip blk) -> Tip blk
forall a. Their a -> a
unTheir Their (Tip blk)
theirTip)
        decision :: (PipelineDecision n, MkPipelineDecision)
decision = MkPipelineDecision
-> Nat n
-> WithOrigin BlockNo
-> WithOrigin BlockNo
-> (PipelineDecision n, MkPipelineDecision)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> WithOrigin BlockNo
-> WithOrigin BlockNo
-> (PipelineDecision n, MkPipelineDecision)
runPipelineDecision
          MkPipelineDecision
mkPipelineDecision
          Nat n
n
          WithOrigin BlockNo
candTipBlockNo
          WithOrigin BlockNo
theirTipBlockNo

    handleNext :: KnownIntersectionState blk
               -> MkPipelineDecision
               -> Nat n
               -> Consensus (ClientStNext n) blk m
    handleNext :: KnownIntersectionState blk
-> MkPipelineDecision -> Nat n -> Consensus (ClientStNext n) blk m
handleNext KnownIntersectionState blk
kis MkPipelineDecision
mkPipelineDecision Nat n
n = ClientStNext :: forall (n :: N) header point tip (m :: * -> *) a.
(header -> tip -> m (ClientPipelinedStIdle n header point tip m a))
-> (point
    -> tip -> m (ClientPipelinedStIdle n header point tip m a))
-> ClientStNext n header point tip m a
ClientStNext
      { recvMsgRollForward :: Header blk
-> Tip blk
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgRollForward  = \Header blk
hdr Tip blk
theirTip -> do
          Tracer m (TraceChainSyncClientEvent blk)
-> TraceChainSyncClientEvent blk -> m ()
forall (m :: * -> *) a. Tracer m a -> a -> m ()
traceWith Tracer m (TraceChainSyncClientEvent blk)
tracer (TraceChainSyncClientEvent blk -> m ())
-> TraceChainSyncClientEvent blk -> m ()
forall a b. (a -> b) -> a -> b
$ Header blk -> TraceChainSyncClientEvent blk
forall blk. Header blk -> TraceChainSyncClientEvent blk
TraceDownloadedHeader Header blk
hdr
          KnownIntersectionState blk
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState KnownIntersectionState blk
kis (Stateful
   m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
 -> m (ClientPipelinedStIdle
         n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$
            MkPipelineDecision
-> Nat n
-> Header blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> Header blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
rollForward MkPipelineDecision
mkPipelineDecision Nat n
n Header blk
hdr (Tip blk -> Their (Tip blk)
forall a. a -> Their a
Their Tip blk
theirTip)
      , recvMsgRollBackward :: Point blk
-> Tip blk
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
recvMsgRollBackward = \Point blk
intersection Tip blk
theirTip -> do
          let intersection' :: Point blk
              intersection' :: Point blk
intersection' = Point blk -> Point blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point blk
intersection
          Tracer m (TraceChainSyncClientEvent blk)
-> TraceChainSyncClientEvent blk -> m ()
forall (m :: * -> *) a. Tracer m a -> a -> m ()
traceWith Tracer m (TraceChainSyncClientEvent blk)
tracer (TraceChainSyncClientEvent blk -> m ())
-> TraceChainSyncClientEvent blk -> m ()
forall a b. (a -> b) -> a -> b
$ Point blk -> TraceChainSyncClientEvent blk
forall blk. Point blk -> TraceChainSyncClientEvent blk
TraceRolledBack Point blk
intersection'
          KnownIntersectionState blk
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState KnownIntersectionState blk
kis (Stateful
   m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
 -> m (ClientPipelinedStIdle
         n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (ClientPipelinedStIdle
        n (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$
            MkPipelineDecision
-> Nat n
-> Point blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> Point blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
rollBackward MkPipelineDecision
mkPipelineDecision Nat n
n Point blk
intersection' (Tip blk -> Their (Tip blk)
forall a. a -> Their a
Their Tip blk
theirTip)
      }

    rollForward :: MkPipelineDecision
                -> Nat n
                -> Header blk
                -> Their (Tip blk)
                -> Stateful m blk
                     (KnownIntersectionState blk)
                     (ClientPipelinedStIdle n)
    rollForward :: MkPipelineDecision
-> Nat n
-> Header blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
rollForward MkPipelineDecision
mkPipelineDecision Nat n
n Header blk
hdr Their (Tip blk)
theirTip
              = (KnownIntersectionState blk
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((KnownIntersectionState blk
  -> m (Consensus (ClientPipelinedStIdle n) blk m))
 -> Stateful
      m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n))
-> (KnownIntersectionState blk
    -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ \KnownIntersectionState blk
kis -> m (Consensus (ClientPipelinedStIdle n) blk m)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a. m a -> m a
traceException (m (Consensus (ClientPipelinedStIdle n) blk m)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> m (Consensus (ClientPipelinedStIdle n) blk m)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ do
      -- Reject the block if invalid
      let hdrHash :: HeaderHash blk
hdrHash  = Header blk -> HeaderHash blk
forall blk. HasHeader (Header blk) => Header blk -> HeaderHash blk
headerHash Header blk
hdr
          hdrPoint :: Point blk
hdrPoint = Header blk -> Point blk
forall blk. HasHeader (Header blk) => Header blk -> Point blk
headerPoint Header blk
hdr
      HeaderHash blk -> Maybe (InvalidBlockReason blk)
isInvalidBlock <- STM m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
 -> m (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> STM m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
forall a b. (a -> b) -> a -> b
$ WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> HeaderHash blk -> Maybe (InvalidBlockReason blk)
forall a. WithFingerprint a -> a
forgetFingerprint (WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk))
 -> HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> STM m (HeaderHash blk -> Maybe (InvalidBlockReason blk))
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock
      Maybe (InvalidBlockReason blk)
-> (InvalidBlockReason blk -> m ()) -> m ()
forall (f :: * -> *) a.
Applicative f =>
Maybe a -> (a -> f ()) -> f ()
whenJust (HeaderHash blk -> Maybe (InvalidBlockReason blk)
isInvalidBlock HeaderHash blk
hdrHash) ((InvalidBlockReason blk -> m ()) -> m ())
-> (InvalidBlockReason blk -> m ()) -> m ()
forall a b. (a -> b) -> a -> b
$ \InvalidBlockReason blk
reason ->
        ChainSyncClientException -> m ()
forall (m' :: * -> *) x'.
MonadThrow m' =>
ChainSyncClientException -> m' x'
disconnect (ChainSyncClientException -> m ())
-> ChainSyncClientException -> m ()
forall a b. (a -> b) -> a -> b
$ Point blk -> InvalidBlockReason blk -> ChainSyncClientException
forall blk.
LedgerSupportsProtocol blk =>
Point blk -> InvalidBlockReason blk -> ChainSyncClientException
InvalidBlock Point blk
hdrPoint InvalidBlockReason blk
reason

      -- Get the ledger view required to validate the header
      -- NOTE: This will block if we are too far behind.
      IntersectCheck blk
intersectCheck <- STM m (IntersectCheck blk) -> m (IntersectCheck blk)
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m (IntersectCheck blk) -> m (IntersectCheck blk))
-> STM m (IntersectCheck blk) -> m (IntersectCheck blk)
forall a b. (a -> b) -> a -> b
$ do
        -- Before obtaining a 'LedgerView', we must find the most recent
        -- intersection with the current chain. Note that this is cheap when
        -- the chain and candidate haven't changed.
        Maybe (KnownIntersectionState blk)
mKis' <- KnownIntersectionState blk
-> STM m (Maybe (KnownIntersectionState blk))
intersectsWithCurrentChain KnownIntersectionState blk
kis
        case Maybe (KnownIntersectionState blk)
mKis' of
          Maybe (KnownIntersectionState blk)
Nothing -> IntersectCheck blk -> STM m (IntersectCheck blk)
forall (m :: * -> *) a. Monad m => a -> m a
return IntersectCheck blk
forall blk. IntersectCheck blk
NoLongerIntersects
          Just kis' :: KnownIntersectionState blk
kis'@KnownIntersectionState { Point blk
mostRecentIntersection :: Point blk
$sel:mostRecentIntersection:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Point blk
mostRecentIntersection } -> do
            -- We're calling 'ledgerViewForecastAt' in the same STM transaction
            -- as 'intersectsWithCurrentChain'. This guarantees the former's
            -- precondition: the intersection is within the last @k@ blocks of
            -- the current chain.
            Forecast (LedgerView (BlockProtocol blk))
forecast <-
              Forecast (LedgerView (BlockProtocol blk))
-> (ExtLedgerState blk
    -> Forecast (LedgerView (BlockProtocol blk)))
-> Maybe (ExtLedgerState blk)
-> Forecast (LedgerView (BlockProtocol blk))
forall b a. b -> (a -> b) -> Maybe a -> b
maybe
                (String -> Forecast (LedgerView (BlockProtocol blk))
forall a. HasCallStack => String -> a
error (String -> Forecast (LedgerView (BlockProtocol blk)))
-> String -> Forecast (LedgerView (BlockProtocol blk))
forall a b. (a -> b) -> a -> b
$
                   String
"intersection not within last k blocks: " String -> ShowS
forall a. Semigroup a => a -> a -> a
<> Point blk -> String
forall a. Show a => a -> String
show Point blk
mostRecentIntersection)
                (LedgerConfig blk
-> LedgerState blk -> Forecast (LedgerView (BlockProtocol blk))
forall blk.
(LedgerSupportsProtocol blk, HasCallStack) =>
LedgerConfig blk
-> LedgerState blk -> Forecast (LedgerView (BlockProtocol blk))
ledgerViewForecastAt (TopLevelConfig blk -> LedgerConfig blk
forall blk. TopLevelConfig blk -> LedgerConfig blk
configLedger TopLevelConfig blk
cfg) (LedgerState blk -> Forecast (LedgerView (BlockProtocol blk)))
-> (ExtLedgerState blk -> LedgerState blk)
-> ExtLedgerState blk
-> Forecast (LedgerView (BlockProtocol blk))
forall b c a. (b -> c) -> (a -> b) -> a -> c
. ExtLedgerState blk -> LedgerState blk
forall blk. ExtLedgerState blk -> LedgerState blk
ledgerState)
                (Maybe (ExtLedgerState blk)
 -> Forecast (LedgerView (BlockProtocol blk)))
-> STM m (Maybe (ExtLedgerState blk))
-> STM m (Forecast (LedgerView (BlockProtocol blk)))
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> Point blk -> STM m (Maybe (ExtLedgerState blk))
getPastLedger Point blk
mostRecentIntersection

            case Except
  OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
-> Either
     OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
forall e a. Except e a -> Either e a
runExcept (Except
   OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
 -> Either
      OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk))))
-> Except
     OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
-> Either
     OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
forall a b. (a -> b) -> a -> b
$ Forecast (LedgerView (BlockProtocol blk))
-> SlotNo
-> Except
     OutsideForecastRange (Ticked (LedgerView (BlockProtocol blk)))
forall a.
Forecast a -> SlotNo -> Except OutsideForecastRange (Ticked a)
forecastFor Forecast (LedgerView (BlockProtocol blk))
forecast (Header blk -> SlotNo
forall b. HasHeader b => b -> SlotNo
blockSlot Header blk
hdr) of
              -- The header is too far ahead of the intersection point with our
              -- current chain. We have to wait until our chain and the
              -- intersection have advanced far enough. This will wait on
              -- changes to the current chain via the call to
              -- 'intersectsWithCurrentChain' befoer it.
              Left OutsideForecastRange{} ->
                STM m (IntersectCheck blk)
forall (stm :: * -> *) a. MonadSTMTx stm => stm a
retry
              Right Ticked (LedgerView (BlockProtocol blk))
ledgerView ->
                IntersectCheck blk -> STM m (IntersectCheck blk)
forall (m :: * -> *) a. Monad m => a -> m a
return (IntersectCheck blk -> STM m (IntersectCheck blk))
-> IntersectCheck blk -> STM m (IntersectCheck blk)
forall a b. (a -> b) -> a -> b
$ KnownIntersectionState blk
-> Ticked (LedgerView (BlockProtocol blk)) -> IntersectCheck blk
forall blk.
KnownIntersectionState blk
-> Ticked (LedgerView (BlockProtocol blk)) -> IntersectCheck blk
Intersects KnownIntersectionState blk
kis' Ticked (LedgerView (BlockProtocol blk))
ledgerView

      case IntersectCheck blk
intersectCheck of
        IntersectCheck blk
NoLongerIntersects ->
          -- Our chain (tip) has changed and it no longer intersects with the
          -- candidate fragment, so we have to find a new intersection, but
          -- first drain the pipe.
          ()
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState ()
            (Stateful m blk () (ClientPipelinedStIdle n)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ Nat n
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall s (n :: N).
NoThunks s =>
Nat n
-> Stateful m blk s (ClientPipelinedStIdle 'Z)
-> Stateful m blk s (ClientPipelinedStIdle n)
drainThePipe Nat n
n
            (Stateful m blk () (ClientPipelinedStIdle 'Z)
 -> Stateful m blk () (ClientPipelinedStIdle n))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ (Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult)
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
findIntersection Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
forall blk.
BlockSupportsProtocol blk =>
Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
NoMoreIntersection

        Intersects KnownIntersectionState blk
kis' Ticked (LedgerView (BlockProtocol blk))
ledgerView -> do
          -- Our chain still intersects with the candidate fragment and we
          -- have obtained a 'LedgerView' that we can use to validate @hdr@.

          let KnownIntersectionState {
                  Our (Tip blk)
ourTip :: Our (Tip blk)
$sel:ourTip:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Our (Tip blk)
ourTip
                , AnchoredFragment (Header blk)
ourFrag :: AnchoredFragment (Header blk)
$sel:ourFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag
                , AnchoredFragment (Header blk)
theirFrag :: AnchoredFragment (Header blk)
$sel:theirFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag
                , HeaderStateHistory blk
theirHeaderStateHistory :: HeaderStateHistory blk
$sel:theirHeaderStateHistory:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> HeaderStateHistory blk
theirHeaderStateHistory
                , Point blk
mostRecentIntersection :: Point blk
$sel:mostRecentIntersection:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Point blk
mostRecentIntersection
                } = KnownIntersectionState blk
kis'

          -- Validate header
          let expectPrevHash :: ChainHash blk
expectPrevHash = ChainHash (Header blk) -> ChainHash blk
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
ChainHash b -> ChainHash b'
castHash (AnchoredFragment (Header blk) -> ChainHash (Header blk)
forall block.
HasHeader block =>
AnchoredFragment block -> ChainHash block
AF.headHash AnchoredFragment (Header blk)
theirFrag)
              actualPrevHash :: ChainHash blk
actualPrevHash = Header blk -> ChainHash blk
forall blk. GetPrevHash blk => Header blk -> ChainHash blk
headerPrevHash Header blk
hdr
          Bool -> m () -> m ()
forall (f :: * -> *). Applicative f => Bool -> f () -> f ()
when (ChainHash blk
actualPrevHash ChainHash blk -> ChainHash blk -> Bool
forall a. Eq a => a -> a -> Bool
/= ChainHash blk
expectPrevHash) (m () -> m ()) -> m () -> m ()
forall a b. (a -> b) -> a -> b
$
            ChainSyncClientException -> m ()
forall (m' :: * -> *) x'.
MonadThrow m' =>
ChainSyncClientException -> m' x'
disconnect (ChainSyncClientException -> m ())
-> ChainSyncClientException -> m ()
forall a b. (a -> b) -> a -> b
$ ChainHash blk
-> ChainHash blk
-> Our (Tip blk)
-> Their (Tip blk)
-> ChainSyncClientException
forall blk.
BlockSupportsProtocol blk =>
ChainHash blk
-> ChainHash blk
-> Our (Tip blk)
-> Their (Tip blk)
-> ChainSyncClientException
DoesntFit ChainHash blk
actualPrevHash ChainHash blk
expectPrevHash Our (Tip blk)
ourTip Their (Tip blk)
theirTip

          HeaderStateHistory blk
theirHeaderStateHistory' <-
            case Except (HeaderError blk) (HeaderStateHistory blk)
-> Either (HeaderError blk) (HeaderStateHistory blk)
forall e a. Except e a -> Either e a
runExcept (Except (HeaderError blk) (HeaderStateHistory blk)
 -> Either (HeaderError blk) (HeaderStateHistory blk))
-> Except (HeaderError blk) (HeaderStateHistory blk)
-> Either (HeaderError blk) (HeaderStateHistory blk)
forall a b. (a -> b) -> a -> b
$ TopLevelConfig blk
-> Ticked (LedgerView (BlockProtocol blk))
-> Header blk
-> HeaderStateHistory blk
-> Except (HeaderError blk) (HeaderStateHistory blk)
forall blk.
(BlockSupportsProtocol blk, ValidateEnvelope blk) =>
TopLevelConfig blk
-> Ticked (LedgerView (BlockProtocol blk))
-> Header blk
-> HeaderStateHistory blk
-> Except (HeaderError blk) (HeaderStateHistory blk)
validateHeader TopLevelConfig blk
cfg Ticked (LedgerView (BlockProtocol blk))
ledgerView Header blk
hdr HeaderStateHistory blk
theirHeaderStateHistory of
              Right HeaderStateHistory blk
theirHeaderStateHistory' -> HeaderStateHistory blk -> m (HeaderStateHistory blk)
forall (m :: * -> *) a. Monad m => a -> m a
return HeaderStateHistory blk
theirHeaderStateHistory'
              Left  HeaderError blk
vErr ->
                ChainSyncClientException -> m (HeaderStateHistory blk)
forall (m' :: * -> *) x'.
MonadThrow m' =>
ChainSyncClientException -> m' x'
disconnect (ChainSyncClientException -> m (HeaderStateHistory blk))
-> ChainSyncClientException -> m (HeaderStateHistory blk)
forall a b. (a -> b) -> a -> b
$ Point blk
-> HeaderError blk
-> Our (Tip blk)
-> Their (Tip blk)
-> ChainSyncClientException
forall blk.
(BlockSupportsProtocol blk, ValidateEnvelope blk) =>
Point blk
-> HeaderError blk
-> Our (Tip blk)
-> Their (Tip blk)
-> ChainSyncClientException
HeaderError Point blk
hdrPoint HeaderError blk
vErr Our (Tip blk)
ourTip Their (Tip blk)
theirTip

          let theirFrag' :: AnchoredFragment (Header blk)
theirFrag' = AnchoredFragment (Header blk)
theirFrag AnchoredFragment (Header blk)
-> Header blk -> AnchoredFragment (Header blk)
forall block.
(HasHeader block, HasCallStack) =>
AnchoredFragment block -> block -> AnchoredFragment block
:> Header blk
hdr
              -- Advance the most recent intersection if we have the same header
              -- on our fragment too. This is cheaper than recomputing the
              -- intersection from scratch.
              mostRecentIntersection' :: Point blk
mostRecentIntersection'
                | Just Header blk
ourSuccessor <-
                    Point (Header blk)
-> AnchoredFragment (Header blk) -> Maybe (Header blk)
forall block.
HasHeader block =>
Point block -> AnchoredFragment block -> Maybe block
AF.successorBlock (Point blk -> Point (Header blk)
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point blk
mostRecentIntersection) AnchoredFragment (Header blk)
ourFrag
                , Header blk -> HeaderHash blk
forall blk. HasHeader (Header blk) => Header blk -> HeaderHash blk
headerHash Header blk
ourSuccessor HeaderHash blk -> HeaderHash blk -> Bool
forall a. Eq a => a -> a -> Bool
== Header blk -> HeaderHash blk
forall blk. HasHeader (Header blk) => Header blk -> HeaderHash blk
headerHash Header blk
hdr
                = Header blk -> Point blk
forall blk. HasHeader (Header blk) => Header blk -> Point blk
headerPoint Header blk
hdr
                | Bool
otherwise
                = Point blk
mostRecentIntersection
              kis'' :: KnownIntersectionState blk
kis'' = ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall blk.
(HasHeader blk, HasHeader (Header blk), HasAnnTip blk,
 ConsensusProtocol (BlockProtocol blk), HasCallStack) =>
ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
assertKnownIntersectionInvariants (TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
forall blk.
TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
configConsensus TopLevelConfig blk
cfg) (KnownIntersectionState blk -> KnownIntersectionState blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall a b. (a -> b) -> a -> b
$
                KnownIntersectionState :: forall blk.
AnchoredFragment (Header blk)
-> HeaderStateHistory blk
-> AnchoredFragment (Header blk)
-> Our (Tip blk)
-> Point blk
-> KnownIntersectionState blk
KnownIntersectionState {
                    $sel:theirFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
theirFrag               = AnchoredFragment (Header blk)
theirFrag'
                  , $sel:theirHeaderStateHistory:KnownIntersectionState :: HeaderStateHistory blk
theirHeaderStateHistory = HeaderStateHistory blk
theirHeaderStateHistory'
                  , $sel:ourFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
ourFrag                 = AnchoredFragment (Header blk)
ourFrag
                  , $sel:ourTip:KnownIntersectionState :: Our (Tip blk)
ourTip                  = Our (Tip blk)
ourTip
                  , $sel:mostRecentIntersection:KnownIntersectionState :: Point blk
mostRecentIntersection  = Point blk
mostRecentIntersection'
                  }
          STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar m (AnchoredFragment (Header blk))
-> AnchoredFragment (Header blk) -> STM m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
StrictTVar m a -> a -> STM m ()
writeTVar StrictTVar m (AnchoredFragment (Header blk))
varCandidate AnchoredFragment (Header blk)
theirFrag'

          KnownIntersectionState blk
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState KnownIntersectionState blk
kis'' (Stateful
   m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
nextStep MkPipelineDecision
mkPipelineDecision Nat n
n Their (Tip blk)
theirTip

    rollBackward :: MkPipelineDecision
                 -> Nat n
                 -> Point blk
                 -> Their (Tip blk)
                 -> Stateful m blk
                      (KnownIntersectionState blk)
                      (ClientPipelinedStIdle n)
    rollBackward :: MkPipelineDecision
-> Nat n
-> Point blk
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
rollBackward MkPipelineDecision
mkPipelineDecision Nat n
n Point blk
rollBackPoint
                 Their (Tip blk)
theirTip
               = (KnownIntersectionState blk
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((KnownIntersectionState blk
  -> m (Consensus (ClientPipelinedStIdle n) blk m))
 -> Stateful
      m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n))
-> (KnownIntersectionState blk
    -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ \KnownIntersectionState
                   { AnchoredFragment (Header blk)
theirFrag :: AnchoredFragment (Header blk)
$sel:theirFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
theirFrag
                   , HeaderStateHistory blk
theirHeaderStateHistory :: HeaderStateHistory blk
$sel:theirHeaderStateHistory:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> HeaderStateHistory blk
theirHeaderStateHistory
                   , AnchoredFragment (Header blk)
ourFrag :: AnchoredFragment (Header blk)
$sel:ourFrag:KnownIntersectionState :: forall blk.
KnownIntersectionState blk -> AnchoredFragment (Header blk)
ourFrag
                   , Our (Tip blk)
ourTip :: Our (Tip blk)
$sel:ourTip:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Our (Tip blk)
ourTip
                   , Point blk
mostRecentIntersection :: Point blk
$sel:mostRecentIntersection:KnownIntersectionState :: forall blk. KnownIntersectionState blk -> Point blk
mostRecentIntersection
                   } -> m (Consensus (ClientPipelinedStIdle n) blk m)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a. m a -> m a
traceException (m (Consensus (ClientPipelinedStIdle n) blk m)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> m (Consensus (ClientPipelinedStIdle n) blk m)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ do
        case Point blk
-> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall blk.
(BlockSupportsProtocol blk, HasAnnTip blk) =>
Point blk
-> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
attemptRollback Point blk
rollBackPoint (AnchoredFragment (Header blk)
theirFrag, HeaderStateHistory blk
theirHeaderStateHistory) of
          -- Remember that we use our current chain fragment as the starting
          -- point for the candidate's chain. Our fragment contained @k@
          -- headers. At this point, the candidate fragment might have grown to
          -- more than @k@ or rolled back to less than @k@ headers.
          --
          -- But now, it rolled back to some point that is not on the fragment,
          -- which means that it tried to roll back to some point before one of
          -- the last @k@ headers we initially started from. We could never
          -- switch to this fork anyway, so just disconnect. Furthermore, our
          -- current chain might have advanced in the meantime, so the point we
          -- would have to roll back to might have been much further back than
          -- @k@ blocks (> @k@ + the number of blocks we have advanced since
          -- starting syncing).
          --
          -- INVARIANT: a candidate fragment contains @>=k@ headers (unless
          -- near genesis, in which case we mean the total number of blocks in
          -- the fragment) minus @r@ headers where @r <= k@. This ghost
          -- variable @r@ indicates the number of headers we temporarily
          -- rolled back. Such a rollback must always be followed by rolling
          -- forward @s@ new headers where @s >= r@.
          --
          -- Thus, @k - r + s >= k@.
          Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
Nothing ->
            Nat n
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (n :: N).
Nat n
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
terminateAfterDrain Nat n
n (ChainSyncClientResult
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$
              Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
forall blk.
BlockSupportsProtocol blk =>
Point blk
-> Our (Tip blk) -> Their (Tip blk) -> ChainSyncClientResult
RolledBackPastIntersection Point blk
rollBackPoint Our (Tip blk)
ourTip Their (Tip blk)
theirTip

          Just (AnchoredFragment (Header blk)
theirFrag', HeaderStateHistory blk
theirHeaderStateHistory') -> do
            -- We just rolled back to @intersection@, either our most recent
            -- intersection was after or at @intersection@, in which case
            -- @intersection@ becomes the new most recent intersection.
            --
            -- But if the most recent intersection was /before/ @intersection@,
            -- then the most recent intersection doesn't change.
            let mostRecentIntersection' :: Point blk
mostRecentIntersection'
                  | Point (Header blk) -> AnchoredFragment (Header blk) -> Bool
forall block.
HasHeader block =>
Point block -> AnchoredFragment block -> Bool
AF.withinFragmentBounds (Point blk -> Point (Header blk)
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point blk
rollBackPoint) AnchoredFragment (Header blk)
ourFrag
                  = Point blk
rollBackPoint
                  | Bool
otherwise
                  = Point blk
mostRecentIntersection
                kis' :: KnownIntersectionState blk
kis' = ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall blk.
(HasHeader blk, HasHeader (Header blk), HasAnnTip blk,
 ConsensusProtocol (BlockProtocol blk), HasCallStack) =>
ConsensusConfig (BlockProtocol blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
assertKnownIntersectionInvariants (TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
forall blk.
TopLevelConfig blk -> ConsensusConfig (BlockProtocol blk)
configConsensus TopLevelConfig blk
cfg) (KnownIntersectionState blk -> KnownIntersectionState blk)
-> KnownIntersectionState blk -> KnownIntersectionState blk
forall a b. (a -> b) -> a -> b
$
                  KnownIntersectionState :: forall blk.
AnchoredFragment (Header blk)
-> HeaderStateHistory blk
-> AnchoredFragment (Header blk)
-> Our (Tip blk)
-> Point blk
-> KnownIntersectionState blk
KnownIntersectionState {
                      $sel:theirFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
theirFrag               = AnchoredFragment (Header blk)
theirFrag'
                    , $sel:theirHeaderStateHistory:KnownIntersectionState :: HeaderStateHistory blk
theirHeaderStateHistory = HeaderStateHistory blk
theirHeaderStateHistory'
                    , $sel:ourFrag:KnownIntersectionState :: AnchoredFragment (Header blk)
ourFrag                 = AnchoredFragment (Header blk)
ourFrag
                    , $sel:ourTip:KnownIntersectionState :: Our (Tip blk)
ourTip                  = Our (Tip blk)
ourTip
                    , $sel:mostRecentIntersection:KnownIntersectionState :: Point blk
mostRecentIntersection  = Point blk
mostRecentIntersection'
                    }
            STM m () -> m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically (STM m () -> m ()) -> STM m () -> m ()
forall a b. (a -> b) -> a -> b
$ StrictTVar m (AnchoredFragment (Header blk))
-> AnchoredFragment (Header blk) -> STM m ()
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
StrictTVar m a -> a -> STM m ()
writeTVar StrictTVar m (AnchoredFragment (Header blk))
varCandidate AnchoredFragment (Header blk)
theirFrag'

            KnownIntersectionState blk
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState KnownIntersectionState blk
kis' (Stateful
   m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
forall (n :: N).
MkPipelineDecision
-> Nat n
-> Their (Tip blk)
-> Stateful
     m blk (KnownIntersectionState blk) (ClientPipelinedStIdle n)
nextStep MkPipelineDecision
mkPipelineDecision Nat n
n Their (Tip blk)
theirTip

    -- | Gracefully terminate the connection with the upstream node with the
    -- given result.
    terminate :: ChainSyncClientResult -> Consensus (ClientPipelinedStIdle 'Z) blk m
    terminate :: ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
terminate = ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
forall a header point tip (m :: * -> *).
a -> ClientPipelinedStIdle 'Z header point tip m a
SendMsgDone

    -- | Same as 'terminate', but first 'drainThePipe'.
    terminateAfterDrain :: Nat n -> ChainSyncClientResult -> m (Consensus (ClientPipelinedStIdle n) blk m)
    terminateAfterDrain :: Nat n
-> ChainSyncClientResult
-> m (Consensus (ClientPipelinedStIdle n) blk m)
terminateAfterDrain Nat n
n ChainSyncClientResult
result =
          ()
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
NoThunks s =>
s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState ()
        (Stateful m blk () (ClientPipelinedStIdle n)
 -> m (Consensus (ClientPipelinedStIdle n) blk m))
-> Stateful m blk () (ClientPipelinedStIdle n)
-> m (Consensus (ClientPipelinedStIdle n) blk m)
forall a b. (a -> b) -> a -> b
$ Nat n
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall s (n :: N).
NoThunks s =>
Nat n
-> Stateful m blk s (ClientPipelinedStIdle 'Z)
-> Stateful m blk s (ClientPipelinedStIdle n)
drainThePipe Nat n
n
        (Stateful m blk () (ClientPipelinedStIdle 'Z)
 -> Stateful m blk () (ClientPipelinedStIdle n))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
-> Stateful m blk () (ClientPipelinedStIdle n)
forall a b. (a -> b) -> a -> b
$ (()
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
forall (m :: * -> *) blk s
       (st :: * -> * -> * -> (* -> *) -> * -> *).
(s -> m (Consensus st blk m)) -> Stateful m blk s st
Stateful ((()
  -> m (ClientPipelinedStIdle
          'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
 -> Stateful m blk () (ClientPipelinedStIdle 'Z))
-> (()
    -> m (ClientPipelinedStIdle
            'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> Stateful m blk () (ClientPipelinedStIdle 'Z)
forall a b. (a -> b) -> a -> b
$ m (ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ()
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. a -> b -> a
const (m (ClientPipelinedStIdle
      'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
 -> ()
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
-> ()
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ ClientPipelinedStIdle
  'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall (m :: * -> *) a. Monad m => a -> m a
return (ClientPipelinedStIdle
   'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
 -> m (ClientPipelinedStIdle
         'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult))
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
-> m (ClientPipelinedStIdle
        'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult)
forall a b. (a -> b) -> a -> b
$ ChainSyncClientResult
-> ClientPipelinedStIdle
     'Z (Header blk) (Point blk) (Tip blk) m ChainSyncClientResult
terminate ChainSyncClientResult
result

    -- | Disconnect from the upstream node by throwing the given exception.
    -- The cleanup is handled in 'bracketChainSyncClient'.
    disconnect :: forall m' x'. MonadThrow m'
               => ChainSyncClientException -> m' x'
    disconnect :: ChainSyncClientException -> m' x'
disconnect = ChainSyncClientException -> m' x'
forall (m :: * -> *) e a. (MonadThrow m, Exception e) => e -> m a
throwIO

    -- | Trace any 'ChainSyncClientException' if thrown.
    traceException :: m a -> m a
    traceException :: m a -> m a
traceException m a
m = m a
m m a -> (ChainSyncClientException -> m a) -> m a
forall (m :: * -> *) e a.
(MonadCatch m, Exception e) =>
m a -> (e -> m a) -> m a
`catch` \(ChainSyncClientException
e :: ChainSyncClientException) -> do
      Tracer m (TraceChainSyncClientEvent blk)
-> TraceChainSyncClientEvent blk -> m ()
forall (m :: * -> *) a. Tracer m a -> a -> m ()
traceWith Tracer m (TraceChainSyncClientEvent blk)
tracer (TraceChainSyncClientEvent blk -> m ())
-> TraceChainSyncClientEvent blk -> m ()
forall a b. (a -> b) -> a -> b
$ ChainSyncClientException -> TraceChainSyncClientEvent blk
forall blk.
ChainSyncClientException -> TraceChainSyncClientEvent blk
TraceException ChainSyncClientException
e
      ChainSyncClientException -> m a
forall (m :: * -> *) e a. (MonadThrow m, Exception e) => e -> m a
throwIO ChainSyncClientException
e

    ourTipFromChain :: AnchoredFragment (Header blk) -> Our (Tip blk)
    ourTipFromChain :: AnchoredFragment (Header blk) -> Our (Tip blk)
ourTipFromChain = Tip blk -> Our (Tip blk)
forall a. a -> Our a
Our (Tip blk -> Our (Tip blk))
-> (AnchoredFragment (Header blk) -> Tip blk)
-> AnchoredFragment (Header blk)
-> Our (Tip blk)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Anchor (Header blk) -> Tip blk
forall a b. (HeaderHash a ~ HeaderHash b) => Anchor a -> Tip b
AF.anchorToTip (Anchor (Header blk) -> Tip blk)
-> (AnchoredFragment (Header blk) -> Anchor (Header blk))
-> AnchoredFragment (Header blk)
-> Tip blk
forall b c a. (b -> c) -> (a -> b) -> a -> c
. AnchoredFragment (Header blk) -> Anchor (Header blk)
forall block.
HasHeader block =>
AnchoredFragment block -> Anchor block
AF.headAnchor

    -- Recent offsets
    --
    -- These offsets are used to find an intersection point between our chain
    -- and the upstream node's. We use the fibonacci sequence to try blocks
    -- closer to our tip, and fewer blocks further down the chain. It is
    -- important that this sequence constains at least a point @k@ back: if no
    -- intersection can be found at most @k@ back, then this is not a peer
    -- that we can sync with (since we will never roll back more than @k).
    --
    -- For @k = 2160@, this evaluates to
    --
    -- > [0,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2160]
    --
    -- For @k = 5@ (during testing), this evaluates to
    --
    -- > [0,1,2,3,5]
    --
    -- In case the fragment contains less than @k@ blocks, we use the length
    -- of the fragment as @k@. This ensures that the oldest rollback point is
    -- selected.
    offsets :: Word64 -> [Word64]
    offsets :: Word64 -> [Word64]
offsets Word64
maxOffset = [Word64
0] [Word64] -> [Word64] -> [Word64]
forall a. [a] -> [a] -> [a]
++ (Word64 -> Bool) -> [Word64] -> [Word64]
forall a. (a -> Bool) -> [a] -> [a]
takeWhile (Word64 -> Word64 -> Bool
forall a. Ord a => a -> a -> Bool
< Word64
l) [Word64 -> Word64
fib Word64
n | Word64
n <- [Word64
2..]] [Word64] -> [Word64] -> [Word64]
forall a. [a] -> [a] -> [a]
++ [Word64
l]
      where
        l :: Word64
l = Word64
k Word64 -> Word64 -> Word64
forall a. Ord a => a -> a -> a
`min` Word64
maxOffset

    k :: Word64
    k :: Word64
k = SecurityParam -> Word64
maxRollbacks (SecurityParam -> Word64) -> SecurityParam -> Word64
forall a b. (a -> b) -> a -> b
$ TopLevelConfig blk -> SecurityParam
forall blk.
ConsensusProtocol (BlockProtocol blk) =>
TopLevelConfig blk -> SecurityParam
configSecurityParam TopLevelConfig blk
cfg

attemptRollback ::
     ( BlockSupportsProtocol blk
     , HasAnnTip blk
     )
  => Point blk
  -> (AnchoredFragment (Header blk), HeaderStateHistory blk)
  -> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
attemptRollback :: Point blk
-> (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
attemptRollback Point blk
rollBackPoint (AnchoredFragment (Header blk)
frag, HeaderStateHistory blk
state) = do
    AnchoredFragment (Header blk)
frag'  <- Point (Header blk)
-> AnchoredFragment (Header blk)
-> Maybe (AnchoredFragment (Header blk))
forall block.
HasHeader block =>
Point block
-> AnchoredFragment block -> Maybe (AnchoredFragment block)
AF.rollback (Point blk -> Point (Header blk)
forall b b'.
Coercible (HeaderHash b) (HeaderHash b') =>
Point b -> Point b'
castPoint Point blk
rollBackPoint) AnchoredFragment (Header blk)
frag
    HeaderStateHistory blk
state' <- Point blk
-> HeaderStateHistory blk -> Maybe (HeaderStateHistory blk)
forall blk.
(BlockSupportsProtocol blk, HasAnnTip blk) =>
Point blk
-> HeaderStateHistory blk -> Maybe (HeaderStateHistory blk)
HeaderStateHistory.rewind Point blk
rollBackPoint HeaderStateHistory blk
state
    (AnchoredFragment (Header blk), HeaderStateHistory blk)
-> Maybe (AnchoredFragment (Header blk), HeaderStateHistory blk)
forall (m :: * -> *) a. Monad m => a -> m a
return (AnchoredFragment (Header blk)
frag', HeaderStateHistory blk
state')

-- | Watch the invalid block checker function for changes (using its
-- fingerprint). Whenever it changes, i.e., a new invalid block is detected,
-- check whether the current candidate fragment contains any header that is
-- invalid, if so, disconnect by throwing an 'InvalidBlock' exception.
--
-- Note that it is possible, yet unlikely, that the candidate fragment
-- contains a header that corresponds to an invalid block, but before we have
-- discovered this (after downloading and validating the block), the upstream
-- node could have rolled back such that its candidate chain no longer
-- contains the invalid block, in which case we do not disconnect from it.
--
-- This function spawns a background thread using the given 'ResourceRegistry'.
--
-- The cost of this check is \( O(cand * check) \) where /cand/ is the size of
-- the candidate fragment and /check/ is the cost of checking whether a block
-- is invalid (typically \( O(\log(invalid)) \) where /invalid/ is the number
-- of invalid blocks).
rejectInvalidBlocks
    :: forall m blk.
       ( IOLike m
       , BlockSupportsProtocol blk
       , LedgerSupportsProtocol blk
       )
    => Tracer m (TraceChainSyncClientEvent blk)
    -> ResourceRegistry m
    -> STM m (WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
       -- ^ Get the invalid block checker
    -> STM m (AnchoredFragment (Header blk))
    -> m ()
rejectInvalidBlocks :: Tracer m (TraceChainSyncClientEvent blk)
-> ResourceRegistry m
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> STM m (AnchoredFragment (Header blk))
-> m ()
rejectInvalidBlocks Tracer m (TraceChainSyncClientEvent blk)
tracer ResourceRegistry m
registry STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock STM m (AnchoredFragment (Header blk))
getCandidate =
    m (Thread m Void) -> m ()
forall (f :: * -> *) a. Functor f => f a -> f ()
void (m (Thread m Void) -> m ()) -> m (Thread m Void) -> m ()
forall a b. (a -> b) -> a -> b
$ ResourceRegistry m
-> String
-> (WithFingerprint
      (HeaderHash blk -> Maybe (InvalidBlockReason blk))
    -> Fingerprint)
-> Maybe Fingerprint
-> STM
     m
     (WithFingerprint
        (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
-> (WithFingerprint
      (HeaderHash blk -> Maybe (InvalidBlockReason blk))
    -> m ())
-> m (Thread m Void)
forall (m :: * -> *) a b.
(IOLike m, Eq b, HasCallStack) =>
ResourceRegistry m
-> String
-> (a -> b)
-> Maybe b
-> STM m a
-> (a -> m ())
-> m (Thread m Void)
onEachChange
      ResourceRegistry m
registry
      String
"ChainSync.Client.rejectInvalidBlocks"
      WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> Fingerprint
forall a. WithFingerprint a -> Fingerprint
getFingerprint
      Maybe Fingerprint
forall a. Maybe a
Nothing
      STM
  m
  (WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk)))
getIsInvalidBlock
      ((HeaderHash blk -> Maybe (InvalidBlockReason blk)) -> m ()
checkInvalid ((HeaderHash blk -> Maybe (InvalidBlockReason blk)) -> m ())
-> (WithFingerprint
      (HeaderHash blk -> Maybe (InvalidBlockReason blk))
    -> HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> WithFingerprint
     (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> m ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. WithFingerprint (HeaderHash blk -> Maybe (InvalidBlockReason blk))
-> HeaderHash blk -> Maybe (InvalidBlockReason blk)
forall a. WithFingerprint a -> a
forgetFingerprint)
  where
    checkInvalid :: (HeaderHash blk -> Maybe (InvalidBlockReason blk)) -> m ()
    checkInvalid :: (HeaderHash blk -> Maybe (InvalidBlockReason blk)) -> m ()
checkInvalid HeaderHash blk -> Maybe (InvalidBlockReason blk)
isInvalidBlock = do
      AnchoredFragment (Header blk)
theirFrag <- STM m (AnchoredFragment (Header blk))
-> m (AnchoredFragment (Header blk))
forall (m :: * -> *) a.
(MonadSTM m, HasCallStack) =>
STM m a -> m a
atomically STM m (AnchoredFragment (Header blk))
getCandidate
      -- The invalid block is likely to be a more recent block, so check from
      -- newest to oldest.
      ((Header blk, InvalidBlockReason blk) -> m ())
-> Maybe (Header blk, InvalidBlockReason blk) -> m ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ ((Header blk -> InvalidBlockReason blk -> m ())
-> (Header blk, InvalidBlockReason blk) -> m ()
forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry Header blk -> InvalidBlockReason blk -> m ()
disconnect) (Maybe (Header blk, InvalidBlockReason blk) -> m ())
-> Maybe (Header blk, InvalidBlockReason blk) -> m ()
forall a b. (a -> b) -> a -> b
$ (Header blk -> Maybe (Header blk, InvalidBlockReason blk))
-> [Header blk] -> Maybe (Header blk, InvalidBlockReason blk)
forall a b (f :: * -> *).
Foldable f =>
(a -> Maybe b) -> f a -> Maybe b
firstJust
        (\Header blk
hdr -> (Header blk
hdr,) (InvalidBlockReason blk -> (Header blk, InvalidBlockReason blk))
-> Maybe (InvalidBlockReason blk)
-> Maybe (Header blk, InvalidBlockReason blk)
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> HeaderHash blk -> Maybe (InvalidBlockReason blk)
isInvalidBlock (Header blk -> HeaderHash blk
forall blk. HasHeader (Header blk) => Header blk -> HeaderHash blk
headerHash Header blk
hdr))
        (AnchoredFragment (Header blk) -> [Header blk]
forall block. AnchoredFragment block -> [block]
AF.toNewestFirst AnchoredFragment (Header blk)
theirFrag)

    disconnect :: Header blk -> InvalidBlockReason blk -> m ()
    disconnect :: Header blk -> InvalidBlockReason blk -> m ()
disconnect Header blk
invalidHeader InvalidBlockReason blk
reason = do
      let ex :: ChainSyncClientException
ex = Point blk -> InvalidBlockReason blk -> ChainSyncClientException
forall blk.
LedgerSupportsProtocol blk =>
Point blk -> InvalidBlockReason blk -> ChainSyncClientException
InvalidBlock (Header blk -> Point blk
forall blk. HasHeader (Header blk) => Header blk -> Point blk
headerPoint Header blk
invalidHeader) InvalidBlockReason blk
reason
      Tracer m (TraceChainSyncClientEvent blk)
-> TraceChainSyncClientEvent blk -> m ()
forall (m :: * -> *) a. Tracer m a -> a -> m ()
traceWith Tracer m (TraceChainSyncClientEvent blk)
tracer (TraceChainSyncClientEvent blk -> m ())
-> TraceChainSyncClientEvent blk -> m ()
forall a b. (a -> b) -> a -> b
$ ChainSyncClientException -> TraceChainSyncClientEvent blk
forall blk.
ChainSyncClientException -> TraceChainSyncClientEvent blk
TraceException ChainSyncClientException
ex
      ChainSyncClientException -> m ()
forall (m :: * -> *) e a. (MonadThrow m, Exception e) => e -> m a
throwIO ChainSyncClientException
ex

-- | Auxiliary data type used as an intermediary result in 'rollForward'.
data IntersectCheck blk =
    -- | The upstream chain no longer intersects with our current chain because
    -- our current chain changed in the background.
    NoLongerIntersects
    -- | The upstream chain still intersects with our chain, return the
    -- resulting 'KnownIntersectionState' and the 'LedgerView' corresponding to
    -- the header 'rollForward' received.
  | Intersects
      (KnownIntersectionState blk)
      (Ticked (LedgerView (BlockProtocol blk)))

{-------------------------------------------------------------------------------
  Explicit state
-------------------------------------------------------------------------------}

-- | Make the state maintained by the chain sync client explicit
--
-- The chain sync client contains of a bunch of functions that basically look
-- like "do some network stuff, compute some stuff, and then continue with
-- such-and-such a new state". We want to make sure to keep that state in NF
-- at all times, but since we don't use a TVar to store it, we cannot reuse
-- the existing infrastructure for checking TVars for NF. Instead, we make
-- the state explicit in the types and do the check in 'continueWithState'.
newtype Stateful m blk s st = Stateful (s -> m (Consensus st blk m))

continueWithState :: forall m blk s st. NoThunks s
                  => s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState :: s -> Stateful m blk s st -> m (Consensus st blk m)
continueWithState !s
s (Stateful s -> m (Consensus st blk m)
f) =
    Maybe String -> m (Consensus st blk m) -> m (Consensus st blk m)
forall a. HasCallStack => Maybe String -> a -> a
checkInvariant (ThunkInfo -> String
forall a. Show a => a -> String
show (ThunkInfo -> String) -> Maybe ThunkInfo -> Maybe String
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> s -> Maybe ThunkInfo
forall a. NoThunks a => a -> Maybe ThunkInfo
unsafeNoThunks s
s) (m (Consensus st blk m) -> m (Consensus st blk m))
-> m (Consensus st blk m) -> m (Consensus st blk m)
forall a b. (a -> b) -> a -> b
$ s -> m (Consensus st blk m)
f s
s

{-------------------------------------------------------------------------------
  Return value
-------------------------------------------------------------------------------}

-- | The Chain sync client only _gracefully_ terminates when the upstream node's
-- chain is not interesting (e.g., forked off too far in the past). By
-- gracefully terminating, the network layer can keep the other mini-protocols
-- connect to the same upstream node running.
--
-- For example, a relay node will often receive connections from nodes syncing
-- from scratch or an old chain. Since these nodes have a chain that is shorter
-- than the relay node's chain, it's useless for the relay node to run the
-- client-side of the chain sync protocol. However, the other direction of the
-- protocol, and, e.g., the transaction submission protocol, should keep
-- running.
data ChainSyncClientResult =
      -- | The server we're connecting to forked more than @k@ blocks ago.
      forall blk. BlockSupportsProtocol blk =>
        ForkTooDeep
          (Point blk)  -- ^ Intersection
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | Our chain changed such that it no longer intersects with the
      -- candidate's fragment, and asking for a new intersection did not yield
      -- one.
    | forall blk. BlockSupportsProtocol blk =>
        NoMoreIntersection
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | We were asked to roll back past the anchor point of the candidate's
      -- fragment. This means the candidate chain no longer forks off within
      -- @k@, making it impossible to switch to.
    | forall blk. BlockSupportsProtocol blk =>
        RolledBackPastIntersection
          (Point blk)  -- ^ Point asked to roll back to
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | We were asked to terminate via the 'ControlMessageSTM'
    | AskedToTerminate

deriving instance Show ChainSyncClientResult

instance Eq ChainSyncClientResult where
  ForkTooDeep (Point blk
a :: Point blk) Our (Tip blk)
b Their (Tip blk)
c == :: ChainSyncClientResult -> ChainSyncClientResult -> Bool
== ForkTooDeep (Point blk
a' :: Point blk') Our (Tip blk)
b' Their (Tip blk)
c' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Point blk
a, Our (Tip blk)
b, Their (Tip blk)
c) (Point blk, Our (Tip blk), Their (Tip blk))
-> (Point blk, Our (Tip blk), Their (Tip blk)) -> Bool
forall a. Eq a => a -> a -> Bool
== (Point blk
Point blk
a', Our (Tip blk)
Our (Tip blk)
b', Their (Tip blk)
Their (Tip blk)
c')
  ForkTooDeep{} == ChainSyncClientResult
_ = Bool
False

  NoMoreIntersection (Our (Tip blk)
a :: Our (Tip blk)) Their (Tip blk)
b == NoMoreIntersection (Our (Tip blk)
a' :: Our (Tip blk')) Their (Tip blk)
b' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Our (Tip blk)
a, Their (Tip blk)
b) (Our (Tip blk), Their (Tip blk))
-> (Our (Tip blk), Their (Tip blk)) -> Bool
forall a. Eq a => a -> a -> Bool
== (Our (Tip blk)
Our (Tip blk)
a', Their (Tip blk)
Their (Tip blk)
b')
  NoMoreIntersection{} == ChainSyncClientResult
_ = Bool
False

  RolledBackPastIntersection (Point blk
a :: Point blk) Our (Tip blk)
b Their (Tip blk)
c == RolledBackPastIntersection (Point blk
a' :: Point blk') Our (Tip blk)
b' Their (Tip blk)
c' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Point blk
a, Our (Tip blk)
b, Their (Tip blk)
c) (Point blk, Our (Tip blk), Their (Tip blk))
-> (Point blk, Our (Tip blk), Their (Tip blk)) -> Bool
forall a. Eq a => a -> a -> Bool
== (Point blk
Point blk
a', Our (Tip blk)
Our (Tip blk)
b', Their (Tip blk)
Their (Tip blk)
c')
  RolledBackPastIntersection{} == ChainSyncClientResult
_ = Bool
False

  ChainSyncClientResult
AskedToTerminate == ChainSyncClientResult
AskedToTerminate = Bool
True
  ChainSyncClientResult
AskedToTerminate == ChainSyncClientResult
_ = Bool
False

{-------------------------------------------------------------------------------
  Exception
-------------------------------------------------------------------------------}

-- | When the upstream node violates the protocol or exhibits malicious
-- behaviour, e.g., serving an invalid header or a header corresponding to a
-- known invalid block, we throw an exception to disconnect. This will bring
-- down all miniprotocols in both directions with that node.
data ChainSyncClientException =
      -- | Header validation threw an error.
      forall blk. (BlockSupportsProtocol blk, ValidateEnvelope blk) =>
        HeaderError
          (Point blk)  -- ^ Invalid header
          (HeaderError blk)
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | We send the upstream node a bunch of points from a chain fragment and
      -- the upstream node responded with an intersection point that is not on
      -- our chain fragment, and thus not among the points we sent.
      --
      -- We store the intersection point the upstream node sent us.
    | forall blk. BlockSupportsProtocol blk =>
        InvalidIntersection
          (Point blk)  -- ^ Intersection
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | The received header to roll forward doesn't fit onto the previous
      -- one.
      --
      -- The first 'ChainHash' is the previous hash of the received header and
      -- the second 'ChainHash' is that of the previous one.
    | forall blk. BlockSupportsProtocol blk =>
        DoesntFit
          (ChainHash blk)  -- ^ Received hash
          (ChainHash blk)  -- ^ Expected hash
          (Our   (Tip blk))
          (Their (Tip blk))

      -- | The upstream node's chain contained a block that we know is invalid.
    | forall blk. LedgerSupportsProtocol blk =>
        InvalidBlock
          (Point blk)  -- ^ Invalid block
          (InvalidBlockReason blk)

deriving instance Show ChainSyncClientException

instance Eq ChainSyncClientException where
  HeaderError (Point blk
a :: Point blk) HeaderError blk
b Our (Tip blk)
c Their (Tip blk)
d == :: ChainSyncClientException -> ChainSyncClientException -> Bool
== HeaderError (Point blk
a' :: Point blk') HeaderError blk
b' Our (Tip blk)
c' Their (Tip blk)
d' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Point blk
a, HeaderError blk
b, Our (Tip blk)
c, Their (Tip blk)
d) (Point blk, HeaderError blk, Our (Tip blk), Their (Tip blk))
-> (Point blk, HeaderError blk, Our (Tip blk), Their (Tip blk))
-> Bool
forall a. Eq a => a -> a -> Bool
== (Point blk
Point blk
a', HeaderError blk
HeaderError blk
b', Our (Tip blk)
Our (Tip blk)
c', Their (Tip blk)
Their (Tip blk)
d')
  HeaderError{} == ChainSyncClientException
_ = Bool
False

  InvalidIntersection (Point blk
a :: Point blk) Our (Tip blk)
b Their (Tip blk)
c == InvalidIntersection (Point blk
a' :: Point blk') Our (Tip blk)
b' Their (Tip blk)
c' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Point blk
a, Our (Tip blk)
b, Their (Tip blk)
c) (Point blk, Our (Tip blk), Their (Tip blk))
-> (Point blk, Our (Tip blk), Their (Tip blk)) -> Bool
forall a. Eq a => a -> a -> Bool
== (Point blk
Point blk
a', Our (Tip blk)
Our (Tip blk)
b', Their (Tip blk)
Their (Tip blk)
c')
  InvalidIntersection{} == ChainSyncClientException
_ = Bool
False

  DoesntFit (ChainHash blk
a :: ChainHash blk) ChainHash blk
b Our (Tip blk)
c Their (Tip blk)
d == DoesntFit (ChainHash blk
a' :: ChainHash blk') ChainHash blk
b' Our (Tip blk)
c' Their (Tip blk)
d' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (ChainHash blk
a, ChainHash blk
b, Our (Tip blk)
c, Their (Tip blk)
d) (ChainHash blk, ChainHash blk, Our (Tip blk), Their (Tip blk))
-> (ChainHash blk, ChainHash blk, Our (Tip blk), Their (Tip blk))
-> Bool
forall a. Eq a => a -> a -> Bool
== (ChainHash blk
ChainHash blk
a', ChainHash blk
ChainHash blk
b', Our (Tip blk)
Our (Tip blk)
c', Their (Tip blk)
Their (Tip blk)
d')
  DoesntFit{} == ChainSyncClientException
_ = Bool
False

  InvalidBlock (Point blk
a :: Point blk) InvalidBlockReason blk
b == InvalidBlock (Point blk
a' :: Point blk') InvalidBlockReason blk
b' =
    case (Typeable blk, Typeable blk) => Maybe (blk :~: blk)
forall k (a :: k) (b :: k).
(Typeable a, Typeable b) =>
Maybe (a :~: b)
eqT @blk @blk' of
      Maybe (blk :~: blk)
Nothing   -> Bool
False
      Just blk :~: blk
Refl -> (Point blk
a, InvalidBlockReason blk
b) (Point blk, InvalidBlockReason blk)
-> (Point blk, InvalidBlockReason blk) -> Bool
forall a. Eq a => a -> a -> Bool
== (Point blk
Point blk
a', InvalidBlockReason blk
InvalidBlockReason blk
b')
  InvalidBlock{} == ChainSyncClientException
_ = Bool
False

instance Exception ChainSyncClientException

{-------------------------------------------------------------------------------
  TODO #221: Implement genesis

  Genesis in paper:

    When we compare a candidate to our own chain, and that candidate forks off
    more than k in the past, we compute the intersection point between that
    candidate and our chain, select s slots from both chains, and compare the
    number of blocks within those s slots. If the candidate has more blocks
    in those s slots, we prefer the candidate, otherwise we stick with our own
    chain.

  Genesis as we will implement it:

    * We decide we are in genesis mode if the head of our chain is more than
      @k@ blocks behind the blockchain time. We will have to approximate this
      as @k/f@ /slots/ behind the blockchain time time.
    * In this situation, we must make sure we have a sufficient number of
      upstream nodes "and collect chains from all of them"
    * We still never consider chains that would require /us/ to rollback more
      than k blocks.
    * In order to compare two candidates, we compute the intersection point of
      X of those two candidates and compare the density at point X.




  Scribbled notes during meeting with Duncan:

   geensis mode: compare clock to our chain
   do we have enough peers?
   still only interested in chains that don't fork more than k from our own chain

     downloading headers from a /single/ node, download at least s headers
     inform /other/ peers: "here is a point on our chain"
     if all agree ("intersection imporved") -- all peers agree
     avoid downloading tons of headers
     /if/ there is a difference, get s headers from the peer who disagrees,
       pick the denser one, and ignore the other
       PROBLEM: what if the denser node has invalid block bodies??
-------------------------------------------------------------------------------}

{-------------------------------------------------------------------------------
  Trace events
-------------------------------------------------------------------------------}

-- | Events traced by the Chain Sync Client.
data TraceChainSyncClientEvent blk
  = TraceDownloadedHeader (Header blk)
    -- ^ While following a candidate chain, we rolled forward by downloading a
    -- header.
  | TraceRolledBack (Point blk)
    -- ^ While following a candidate chain, we rolled back to the given point.
  | TraceFoundIntersection (Point blk) (Our (Tip blk)) (Their (Tip blk))
    -- ^ We found an intersection between our chain fragment and the
    -- candidate's chain.
  | TraceException ChainSyncClientException
    -- ^ An exception was thrown by the Chain Sync Client.

deriving instance ( BlockSupportsProtocol blk
                  , Eq (ValidationErr (BlockProtocol blk))
                  , Eq (Header blk)
                  )
               => Eq   (TraceChainSyncClientEvent blk)
deriving instance ( BlockSupportsProtocol blk
                  , Show (Header blk)
                  )
               => Show (TraceChainSyncClientEvent blk)