internal: get pending and queued transaction by address (#22992)

* core, eth, internal, les, light: get pending and queued transaction by address

* core: tiny nitpick fixes

* light: tiny nitpick

Co-authored-by: mark <mark@amis.com>
Co-authored-by: Péter Szilágyi <peterke@gmail.com>

light/txpool.go

@@ -505,6 +505,25 @@ func (pool *TxPool) Content() (map[common.Address]types.Transactions, map[common
 	return pending, queued
 }
 
+// ContentFrom retrieves the data content of the transaction pool, returning the
+// pending as well as queued transactions of this address, grouped by nonce.
+func (pool *TxPool) ContentFrom(addr common.Address) (types.Transactions, types.Transactions) {
+	pool.mu.RLock()
+	defer pool.mu.RUnlock()
+
+	// Retrieve the pending transactions and sort by nonce
+	var pending types.Transactions
+	for _, tx := range pool.pending {
+		account, _ := types.Sender(pool.signer, tx)
+		if account != addr {
+			continue
+		}
+		pending = append(pending, tx)
+	}
+	// There are no queued transactions in a light pool, just return an empty map
+	return pending, types.Transactions{}
+}
+
 // RemoveTransactions removes all given transactions from the pool.
 func (pool *TxPool) RemoveTransactions(txs types.Transactions) {
 	pool.mu.Lock()