| Safe Haskell | Safe-Inferred |
|---|---|
| Language | Haskell2010 |
Ouroboros.Consensus.Util.AnchoredFragment
Description
Utility functions on anchored fragments
Intended for qualified import > import qualified Ouroboros.Consensus.Util.AnchoredFragment as AF
Synopsis
- compareAnchoredFragments ∷ ∀ blk. (BlockSupportsProtocol blk, HasCallStack) ⇒ BlockConfig blk → AnchoredFragment (Header blk) → AnchoredFragment (Header blk) → Ordering
- compareHeadBlockNo ∷ HasHeader b ⇒ AnchoredFragment b → AnchoredFragment b → Ordering
- cross ∷ HasHeader block ⇒ AnchoredFragment block → AnchoredFragment block → Maybe (Point block, AnchoredFragment block)
- forksAtMostKBlocks ∷ HasHeader b ⇒ Word64 → AnchoredFragment b → AnchoredFragment b → Bool
- preferAnchoredCandidate ∷ ∀ blk. (BlockSupportsProtocol blk, HasCallStack) ⇒ BlockConfig blk → AnchoredFragment (Header blk) → AnchoredFragment (Header blk) → Bool
- stripCommonPrefix ∷ ∀ f blk. (Functor f, Foldable f, HasHeader blk) ⇒ Anchor blk → f (AnchoredFragment blk) → (AnchoredFragment blk, f (AnchoredFragment blk))
Documentation
compareAnchoredFragments ∷ ∀ blk. (BlockSupportsProtocol blk, HasCallStack) ⇒ BlockConfig blk → AnchoredFragment (Header blk) → AnchoredFragment (Header blk) → Ordering Source #
Compare two (potentially empty!) AnchoredFragments.
PRECONDITION: Either both fragments are non-empty or they intersect.
For a detailed discussion of this precondition, and a justification for the definition of this function, please refer to the Consensus Report.
Usage note: the primary user of this function is the chain database when sorting fragments that are preferred over our selection. It establishes the precondition in the following way: It will only compare candidate fragments that it has previously verified are preferable to our current chain. Since these fragments intersect with our current chain, they must by transitivity also intersect each other.
compareHeadBlockNo ∷ HasHeader b ⇒ AnchoredFragment b → AnchoredFragment b → Ordering Source #
Compare the headBlockNo, which is a measure of the length of the chain,
of two anchored fragments.
A fragment with a head is always "greater" than one without. When both
fragments have no head (i.e. are empty), they are EQ.
Note that an EBB can share its BlockNo with another regular block. If
such an EBB is the head of one fragment and the regular block with the same
BlockNo is the head of the other fragment, then this function will say
they are EQ, while in fact one fragment should be preferred over the
other.
This is not a big deal as we won't be seeing new EBBs, so they will not be
the head of a fragment very often anyway, only when catching up. As soon as
a new block/header is added to the fragment, the right decision will be
made again (GT or LT).
cross ∷ HasHeader block ⇒ AnchoredFragment block → AnchoredFragment block → Maybe (Point block, AnchoredFragment block) Source #
If the two fragments c1 and c2 intersect, return the intersection
point and join the prefix of c1 before the intersection with the suffix
of c2 after the intersection. The resulting fragment has the same
anchor as c1 and the same head as c2.
Arguments
| ∷ HasHeader b | |
| ⇒ Word64 | How many blocks can it fork? |
| → AnchoredFragment b | Our chain. |
| → AnchoredFragment b | Their chain |
| → Bool | Indicates whether their chain forks at most the specified number of blocks. |
preferAnchoredCandidate Source #
Arguments
| ∷ ∀ blk. (BlockSupportsProtocol blk, HasCallStack) | |
| ⇒ BlockConfig blk | |
| → AnchoredFragment (Header blk) | Our chain |
| → AnchoredFragment (Header blk) | Candidate |
| → Bool |
Lift preferCandidate to AnchoredFragment
PRECONDITION: Either both fragments are non-empty or they intersect.
Usage note: the primary user of this function is the chain database. It
establishes the precondition when comparing a candidate fragment to our
current chain in the following way: The fragment is guaranteed (by the chain
sync client) to intersect with our chain (indeed, within at most k blocks
from our tip, although the exact distance does not matter for
compareAnchoredFragments).
stripCommonPrefix ∷ ∀ f blk. (Functor f, Foldable f, HasHeader blk) ⇒ Anchor blk → f (AnchoredFragment blk) → (AnchoredFragment blk, f (AnchoredFragment blk)) Source #
Strip the common prefix of multiple fragments.
PRECONDITION: all fragments have the given anchor as their anchor.