first commit

ethergo/listener/listener.go

@@ -12,6 +12,7 @@ import (
 	"github.com/ethereum/go-ethereum"
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/rpc"
 	"github.com/ipfs/go-log"
 	"github.com/jpillora/backoff"
 	"github.com/synapsecns/sanguine/core/metrics"
@@ -48,6 +49,8 @@ type chainListener struct {
 	pollInterval, pollIntervalSetting time.Duration
 	// newBlockHandler is an optional handler that is called when a new block is detected.
 	newBlockHandler NewBlockHandler
+	finalityMode    rpc.BlockNumber
+	blockWait       uint64
 }
 
 var (
@@ -66,6 +69,8 @@ func NewChainListener(omnirpcClient client.EVM, store listenerDB.ChainListenerDB
 		client:              omnirpcClient,
 		backoff:             newBackoffConfig(),
 		pollIntervalSetting: time.Millisecond * 50,
+		finalityMode:        FinalityModeLatest,
+		blockWait:           0,
 	}
 
 	for _, option := range options {
@@ -183,6 +188,25 @@ func (c *chainListener) doPoll(parentCtx context.Context, handler HandleLog) (er
 	return nil
 }
 
+func (c chainListener) getBlockNumber(ctx context.Context) (uint64, error) {
+	var block *types.Block
+	var err error
+
+	block, err = c.client.BlockByNumber(ctx, big.NewInt(c.finalityMode.Int64()))
+
+	if err != nil {
+		return 0, err
+	}
+
+	blockNumber := block.Number()
+
+	if c.blockWait > 0 {
+		blockNumber.Sub(blockNumber, big.NewInt(int64(c.blockWait)))
+	}
+
+	return blockNumber.Uint64(), nil
+}
+
 func (c chainListener) getMetadata(parentCtx context.Context) (startBlock, chainID uint64, err error) {
 	var lastIndexed uint64
 	ctx, span := c.handler.Tracer().Start(parentCtx, "getMetadata")

ethergo/listener/options.go

@@ -3,6 +3,8 @@ package listener
 import (
 	"context"
 	"time"
+
+	"github.com/ethereum/go-ethereum/rpc"
 )
 
 // Option is a functional option for chainListener.
@@ -24,3 +26,25 @@ func WithPollInterval(interval time.Duration) Option {
 		c.pollIntervalSetting = interval
 	}
 }
+
+// FinalityMode represents the finality mode for block queries.
+
+const (
+	FinalityModeSafe      rpc.BlockNumber = rpc.SafeBlockNumber
+	FinalityModeFinalized rpc.BlockNumber = rpc.FinalizedBlockNumber
+	FinalityModeLatest    rpc.BlockNumber = rpc.FinalizedBlockNumber
+)
+
+// WithFinalityMode sets the finality mode.
+func WithFinalityMode(mode rpc.BlockNumber) Option {
+	return func(c *chainListener) {
+		c.finalityMode = mode
+	}
+}
+
+// WithBlockWait sets the block wait.
+func WithBlockWait(wait uint64) Option {
+	return func(c *chainListener) {
+		c.blockWait = wait
+	}
+}