| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Ouroboros.Consensus.HeaderStateHistory
Contents
Description
HeaderState history
Intended for qualified import
import Ouroboros.Consensus.HeaderStateHistory (HeaderStateHistory) import qualified Ouroboros.Consensus.HeaderStateHistory as HeaderStateHistory
Synopsis
- newtype HeaderStateHistory blk = HeaderStateHistory {
- unHeaderStateHistory ∷ AnchoredSeq (WithOrigin SlotNo) (HeaderState blk) (HeaderState blk)
- cast ∷ (Coercible (ChainDepState (BlockProtocol blk)) (ChainDepState (BlockProtocol blk')), TipInfo blk ~ TipInfo blk') ⇒ HeaderStateHistory blk → HeaderStateHistory blk'
- current ∷ HeaderStateHistory blk → HeaderState blk
- rewind ∷ ∀ blk. HasAnnTip blk ⇒ Point blk → HeaderStateHistory blk → Maybe (HeaderStateHistory blk)
- trim ∷ Int → HeaderStateHistory blk → HeaderStateHistory blk
- validateHeader ∷ ∀ blk. (BlockSupportsProtocol blk, ValidateEnvelope blk) ⇒ TopLevelConfig blk → LedgerView (BlockProtocol blk) → Header blk → HeaderStateHistory blk → Except (HeaderError blk) (HeaderStateHistory blk)
- fromChain ∷ ApplyBlock (ExtLedgerState blk) blk ⇒ TopLevelConfig blk → ExtLedgerState blk → Chain blk → HeaderStateHistory blk
Documentation
newtype HeaderStateHistory blk Source #
Maintain a history of HeaderStates.
Constructors
| HeaderStateHistory | |
Fields
| |
Instances
cast ∷ (Coercible (ChainDepState (BlockProtocol blk)) (ChainDepState (BlockProtocol blk')), TipInfo blk ~ TipInfo blk') ⇒ HeaderStateHistory blk → HeaderStateHistory blk' Source #
current ∷ HeaderStateHistory blk → HeaderState blk Source #
rewind ∷ ∀ blk. HasAnnTip blk ⇒ Point blk → HeaderStateHistory blk → Maybe (HeaderStateHistory blk) Source #
\( O\(n\) ). Rewind the header state history
NOTE: we don't distinguish headers of regular blocks from headers of EBBs.
Whenever we use "header" it can be either. In practice, EBB headers do not
affect the ChainDepState, but they do affect the AnnTip.
PRECONDITION: the point to rewind to must correspond to a header (or
GenesisPoint) that was previously applied to the header state history.
Rewinding the header state history is intended to be used when switching to a
fork, longer or equally long to the chain to which the current header state
corresponds. So each rewinding should be followed by rolling forward (using
headerStateHistoryPush) at least as many blocks that we have rewound.
Note that repeatedly rewinding a header state history does not make it
possible to rewind it all the way to genesis (this would mean that the whole
historical header state is accumulated or derivable from the current header
state history). For example, rewinding a header state by i blocks and then
rewinding that header state again by j where i + j > k is not possible
and will yield Nothing.
trim ∷ Int → HeaderStateHistory blk → HeaderStateHistory blk Source #
Trim the HeaderStateHistory to the given size, dropping the oldest
snapshots. The anchor will be shifted accordingly.
Note that we do not include the anchor in the size. For example, trimming to 0 results in no snapshots but still an anchor. Trimming to 1 results in 1 snapshot and an anchor.
Validation
validateHeader ∷ ∀ blk. (BlockSupportsProtocol blk, ValidateEnvelope blk) ⇒ TopLevelConfig blk → LedgerView (BlockProtocol blk) → Header blk → HeaderStateHistory blk → Except (HeaderError blk) (HeaderStateHistory blk) Source #
Variation on validateHeader that maintains a
HeaderStateHistory.
This is used only in the chain sync client for header-only validation.
Note: this function does not trim the HeaderStateHistory.
Support for tests
Arguments
| ∷ ApplyBlock (ExtLedgerState blk) blk | |
| ⇒ TopLevelConfig blk | |
| → ExtLedgerState blk | Initial ledger state |
| → Chain blk | |
| → HeaderStateHistory blk |
Create a HeaderStateHistory corresponding to the blocks in the given
Chain.
PRECONDITION: the blocks in the chain are valid.