github.com/onflow/flow-go@v0.35.7-crescendo-preview.23-atree-inlining/state/cluster/badger/translator.go (about)

     1  package badger
     2  
     3  import (
     4  	"fmt"
     5  
     6  	"github.com/onflow/flow-go/model/flow"
     7  	"github.com/onflow/flow-go/state/protocol"
     8  	"github.com/onflow/flow-go/storage"
     9  )
    10  
    11  // Translator is a translation layer that determines the reference block on
    12  // the main chain for a given cluster block, using the reference block from
    13  // the cluster block's payload.
    14  type Translator struct {
    15  	payloads storage.ClusterPayloads
    16  	state    protocol.State
    17  }
    18  
    19  // NewTranslator returns a new block ID translator.
    20  func NewTranslator(payloads storage.ClusterPayloads, state protocol.State) *Translator {
    21  	translator := &Translator{
    22  		payloads: payloads,
    23  		state:    state,
    24  	}
    25  	return translator
    26  }
    27  
    28  // Translate retrieves the reference main-chain block ID for the given cluster
    29  // block ID.
    30  func (t *Translator) Translate(blockID flow.Identifier) (flow.Identifier, error) {
    31  
    32  	payload, err := t.payloads.ByBlockID(blockID)
    33  	if err != nil {
    34  		return flow.ZeroID, fmt.Errorf("could not retrieve reference block payload: %w", err)
    35  	}
    36  
    37  	// if a reference block is specified, use that
    38  	if payload.ReferenceBlockID != flow.ZeroID {
    39  		return payload.ReferenceBlockID, nil
    40  	}
    41  
    42  	// otherwise, we are dealing with a root block, and must retrieve the
    43  	// reference block by epoch number
    44  	//TODO this returns the latest block in the epoch, thus will take slashing
    45  	// into account. We don't slash yet, so this is OK short-term.
    46  	// We should change the API boundaries a bit here, so this chain-aware
    47  	// translation changes to be f(blockID) -> IdentityList rather than
    48  	// f(blockID) -> blockID.
    49  	// REF: https://github.com/dapperlabs/flow-go/issues/4655
    50  	head, err := t.state.Final().Head()
    51  	if err != nil {
    52  		return flow.ZeroID, fmt.Errorf("could not retrieve block: %w", err)
    53  	}
    54  	return head.ID(), nil
    55  }