/
block.go
56 lines (51 loc) · 2.21 KB
/
block.go
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package helpers
import (
"math"
"github.com/pkg/errors"
"github.com/prysmaticlabs/prysm/v3/beacon-chain/state"
"github.com/prysmaticlabs/prysm/v3/config/params"
types "github.com/prysmaticlabs/prysm/v3/consensus-types/primitives"
"github.com/prysmaticlabs/prysm/v3/time/slots"
)
// BlockRootAtSlot returns the block root stored in the BeaconState for a recent slot.
// It returns an error if the requested block root is not within the slot range.
//
// Spec pseudocode definition:
// def get_block_root_at_slot(state: BeaconState, slot: Slot) -> Root:
// """
// Return the block root at a recent ``slot``.
// """
// assert slot < state.slot <= slot + SLOTS_PER_HISTORICAL_ROOT
// return state.block_roots[slot % SLOTS_PER_HISTORICAL_ROOT]
func BlockRootAtSlot(state state.ReadOnlyBeaconState, slot types.Slot) ([]byte, error) {
if math.MaxUint64-slot < params.BeaconConfig().SlotsPerHistoricalRoot {
return []byte{}, errors.New("slot overflows uint64")
}
if slot >= state.Slot() || state.Slot() > slot+params.BeaconConfig().SlotsPerHistoricalRoot {
return []byte{}, errors.Errorf("slot %d out of bounds", slot)
}
return state.BlockRootAtIndex(uint64(slot % params.BeaconConfig().SlotsPerHistoricalRoot))
}
// StateRootAtSlot returns the cached state root at that particular slot. If no state
// root has been cached it will return a zero-hash.
func StateRootAtSlot(state state.ReadOnlyBeaconState, slot types.Slot) ([]byte, error) {
if slot >= state.Slot() || state.Slot() > slot+params.BeaconConfig().SlotsPerHistoricalRoot {
return []byte{}, errors.Errorf("slot %d out of bounds", slot)
}
return state.StateRootAtIndex(uint64(slot % params.BeaconConfig().SlotsPerHistoricalRoot))
}
// BlockRoot returns the block root stored in the BeaconState for epoch start slot.
//
// Spec pseudocode definition:
// def get_block_root(state: BeaconState, epoch: Epoch) -> Root:
// """
// Return the block root at the start of a recent ``epoch``.
// """
// return get_block_root_at_slot(state, compute_start_slot_at_epoch(epoch))
func BlockRoot(state state.ReadOnlyBeaconState, epoch types.Epoch) ([]byte, error) {
s, err := slots.EpochStart(epoch)
if err != nil {
return nil, err
}
return BlockRootAtSlot(state, s)
}