From 5bb32c5a6f5071766630fc45864166e643b395e6 Mon Sep 17 00:00:00 2001
From: jsvisa <delweng@gmail.com>
Date: Fri, 27 Sep 2024 12:34:59 +0000
Subject: [PATCH] add nonce live tracer

Signed-off-by: jsvisa <delweng@gmail.com>
---
 core/tracing/hooks.go     |   1 +
 eth/tracers/live/nonce.go | 108 ++++++++++++++++++++++++++++++++++++++
 2 files changed, 109 insertions(+)
 create mode 100644 eth/tracers/live/nonce.go

diff --git a/core/tracing/hooks.go b/core/tracing/hooks.go
index abab70864c..7915a9ca54 100644
--- a/core/tracing/hooks.go
+++ b/core/tracing/hooks.go
@@ -78,6 +78,7 @@ type Backend interface {
 	BlockByHash(ctx context.Context, hash common.Hash) (*types.Block, error)
 	BlockByNumber(ctx context.Context, number rpc.BlockNumber) (*types.Block, error)
 	GetTransaction(ctx context.Context, txHash common.Hash) (bool, *types.Transaction, common.Hash, uint64, uint64, error)
+	ChainConfig() *params.ChainConfig
 }
 
 type (
diff --git a/eth/tracers/live/nonce.go b/eth/tracers/live/nonce.go
new file mode 100644
index 0000000000..8734eb0350
--- /dev/null
+++ b/eth/tracers/live/nonce.go
@@ -0,0 +1,108 @@
+package live
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"sync/atomic"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/common/hexutil"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/tracing"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/eth/tracers"
+	"github.com/ethereum/go-ethereum/ethdb"
+	"github.com/ethereum/go-ethereum/internal/ethapi"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rpc"
+)
+
+func init() {
+	tracers.LiveDirectory.Register("nonce", newNonce)
+}
+
+type nonce struct {
+	backend tracing.Backend
+	kvdb    ethdb.Database
+	latest  atomic.Uint64
+}
+
+type nonceTracerConfig struct {
+	Path string `json:"path"` // Path to the directory where the tracer logs will be stored
+}
+
+func newNonce(cfg json.RawMessage, stack tracers.LiveApiRegister, backend tracing.Backend) (*tracing.Hooks, error) {
+	var config nonceTracerConfig
+	if cfg != nil {
+		if err := json.Unmarshal(cfg, &config); err != nil {
+			return nil, fmt.Errorf("failed to parse config: %v", err)
+		}
+	}
+	if config.Path == "" {
+		return nil, errors.New("nonce tracer output path is required")
+	}
+
+	kvdb, err := rawdb.NewPebbleDBDatabase(config.Path, 128, 1024, "nonce", false, false)
+	if err != nil {
+		return nil, err
+	}
+
+	n := &nonce{
+		backend: backend,
+		kvdb:    kvdb,
+	}
+	log.Info("Open nonce tracer", "path", config.Path)
+
+	apis := []rpc.API{{Namespace: "eth", Service: n}}
+	stack.RegisterAPIs(apis)
+
+	return &tracing.Hooks{
+		OnBlockStart: n.onBlockStart,
+		OnTxStart:    n.onTxStart,
+	}, nil
+}
+
+func (n *nonce) onBlockStart(ev tracing.BlockEvent) {
+	blknum := ev.Block.NumberU64()
+	n.latest.Store(blknum)
+}
+
+func (n *nonce) onTxStart(vm *tracing.VMContext, tx *types.Transaction, from common.Address) {
+	key := append(from.Bytes(), encodeNumber(tx.Nonce())...)
+	val := tx.Hash().Bytes()
+	if err := n.kvdb.Put(key, val); err != nil {
+		log.Warn("Failed to put nonce kvdb", "err", err)
+	}
+}
+
+func (n *nonce) GetTransactionBySenderAndNonce(ctx context.Context, sender common.Address, nonce hexutil.Uint) (*ethapi.RPCTransaction, error) {
+	// TODO:
+	// 1. return nil if sender is a contract
+	// 2. check with txpool first
+	txHash, err := n.kvdb.Get(append(sender.Bytes(), encodeNumber(uint64(nonce))...))
+	if err != nil {
+		return nil, nil
+	}
+
+	found, tx, blockHash, blockNumber, index, err := n.backend.GetTransaction(ctx, common.BytesToHash(txHash))
+	if err != nil {
+		return nil, err
+	}
+	if !found {
+		return nil, errors.New("transaction not found")
+	}
+
+	header, err := n.backend.HeaderByHash(ctx, blockHash)
+	if err != nil {
+		return nil, err
+	}
+	return ethapi.NewRPCTransaction(tx, blockHash, blockNumber, header.Time, index, header.BaseFee, n.backend.ChainConfig()), nil
+}
+
+func (n *nonce) Close() {
+	if err := n.kvdb.Close(); err != nil {
+		log.Error("Close kvdb failed", "err", err)
+	}
+}