eth/protocols/eth: remove trimReceiptsRLP and simplify handler

eth/protocols/eth/handlers.go

@@ -269,33 +269,28 @@ func handleGetReceipts70(backend Backend, msg Decoder, peer *Peer) error {
 // It does not send the bloom filters for the receipts. It is exposed
 // to allow external packages to test protocol behavior.
 func ServiceGetReceiptsQuery69(chain *core.BlockChain, query GetReceiptsRequest) rlp.RawList[*ReceiptList] {
-	// Gather state data until the fetch or network limits is reached
 	var (
 		bytes    int
 		receipts rlp.RawList[*ReceiptList]
 	)
 	for lookups, hash := range query {
-		if bytes >= softResponseLimit || receipts.Len() >= maxReceiptsServe ||
-			lookups >= 2*maxReceiptsServe {
+		if bytes >= softResponseLimit || receipts.Len() >= maxReceiptsServe || lookups >= 2*maxReceiptsServe {
 			break
 		}
+
 		// Retrieve the requested block's receipts
 		results := chain.GetReceiptsRLP(hash)
 		if results == nil {
-			if header := chain.GetHeaderByHash(hash); header == nil || header.ReceiptHash != types.EmptyRootHash {
-				continue
-			}
-		} else {
-			body := chain.GetBodyRLP(hash)
-			if body == nil {
-				continue
-			}
-			var err error
-			results, err = blockReceiptsToNetwork(results, body)
-			if err != nil {
-				log.Error("Error in block receipts conversion", "hash", hash, "err", err)
-				continue
-			}
+			continue // Can't retrieve the receipts, so we just skip this block.
+		}
+		body := chain.GetBodyRLP(hash)
+		if body == nil {
+			continue // The block body is missing, we also have to skip.
+		}
+		results, _, err := blockReceiptsToNetwork(results, body, receiptQueryParams{})
+		if err != nil {
+			log.Error("Error in block receipts conversion", "hash", hash, "err", err)
+			continue
 		}
 		receipts.AppendRaw(results)
 		bytes += len(results)
@@ -309,9 +304,8 @@ func ServiceGetReceiptsQuery69(chain *core.BlockChain, query GetReceiptsRequest)
 // are omitted from the first block receipt list.
 func serviceGetReceiptsQuery70(chain *core.BlockChain, query GetReceiptsRequest, firstBlockReceiptIndex uint64) (rlp.RawList[*ReceiptList], bool) {
 	var (
-		bytes               int
-		receipts            rlp.RawList[*ReceiptList]
-		lastBlockIncomplete bool
+		bytes    int
+		receipts rlp.RawList[*ReceiptList]
 	)
 	for i, hash := range query {
 		if bytes >= softResponseLimit || receipts.Len() >= maxReceiptsServe {
@@ -319,65 +313,28 @@ func serviceGetReceiptsQuery70(chain *core.BlockChain, query GetReceiptsRequest,
 		}
 		results := chain.GetReceiptsRLP(hash)
 		if results == nil {
-			if header := chain.GetHeaderByHash(hash); header == nil || header.ReceiptHash != types.EmptyRootHash {
-				continue
-			}
-		} else {
-			body := chain.GetBodyRLP(hash)
-			if body == nil {
-				continue
-			}
-			var err error
-			results, err = blockReceiptsToNetwork(results, body)
-			if err != nil {
-				log.Error("Error in block receipts conversion", "hash", hash, "err", err)
-				continue
-			}
+			continue // Can't retrieve the receipts, so we just skip this block.
 		}
-
-		if firstBlockReceiptIndex > 0 && i == 0 {
-			results, lastBlockIncomplete = trimReceiptsRLP(results, int(firstBlockReceiptIndex), maxPacketSize)
-		} else if bytes+len(results) > maxPacketSize {
-			results, lastBlockIncomplete = trimReceiptsRLP(results, 0, maxPacketSize-bytes)
+		body := chain.GetBodyRLP(hash)
+		if body == nil {
+			continue // The block body is missing, we also have to skip.
 		}
-
-		receipts.AppendRaw(results)
-		bytes += len(results)
-	}
-
-	return receipts, lastBlockIncomplete
-}
-
-// trimReceiptsRLP trims raw value from `from` index until it exceeds limit
-func trimReceiptsRLP(receiptsRLP rlp.RawValue, from int, limit int) (rlp.RawValue, bool) {
-	var (
-		out      bytes.Buffer
-		buffer   = rlp.NewEncoderBuffer(&out)
-		iter, _  = rlp.NewListIterator(receiptsRLP)
-		index    int
-		bytes    int
-		overflow bool
-	)
-
-	list := buffer.List()
-	for iter.Next() {
-		if index < from {
-			index++
+		q := receiptQueryParams{sizeLimit: uint64(maxPacketSize - bytes)}
+		if i == 0 {
+			q.firstIndex = firstBlockReceiptIndex
+		}
+		results, incomplete, err := blockReceiptsToNetwork(results, body, q)
+		if err != nil {
+			log.Error("Error in block receipts conversion", "hash", hash, "err", err)
 			continue
 		}
-		receipt := iter.Value()
-		if bytes+len(receipt) > limit {
-			overflow = true
-			break
+		receipts.AppendRaw(results)
+		bytes += len(results)
+		if incomplete {
+			return receipts, true
 		}
-		buffer.Write(receipt)
-		bytes += len(receipt)
-		index++
 	}
-	buffer.ListEnd(list)
-	buffer.Flush()
-
-	return out.Bytes(), overflow
+	return receipts, false
 }
 
 func handleBlockHeaders(backend Backend, msg Decoder, peer *Peer) error {

eth/protocols/eth/receipt.go

@@ -240,12 +240,17 @@ func (rl *ReceiptList) LogsSize() (uint64, error) {
 	return size, nil
 }
 
-// blockReceiptsToNetwork takes a slice of rlp-encoded receipts, and transactions,
-// and re-encodes them for the network protocol.
-func blockReceiptsToNetwork(blockReceipts, blockBody rlp.RawValue) ([]byte, error) {
+type receiptQueryParams struct {
+	firstIndex uint64
+	sizeLimit  uint64
+}
+
+// blockReceiptsToNetwork takes a slice of rlp-encoded receipts (in the 'storage' encoding),
+// and an encoded block body, and re-encodes the receipts for the network protocol.
+func blockReceiptsToNetwork(blockReceipts, blockBody rlp.RawValue, q receiptQueryParams) (output []byte, incomplete bool, err error) {
 	txTypesIter, err := txTypesInBody(blockBody)
 	if err != nil {
-		return nil, fmt.Errorf("invalid block body: %v", err)
+		return nil, false, fmt.Errorf("invalid block body: %v", err)
 	}
 	nextTxType, stopTxTypes := iter.Pull(txTypesIter)
 	defer stopTxTypes()
@@ -256,9 +261,24 @@ func blockReceiptsToNetwork(blockReceipts, blockBody rlp.RawValue) ([]byte, erro
 		it, _ = rlp.NewListIterator(blockReceipts)
 	)
 	outer := enc.List()
-	for i := 0; it.Next(); i++ {
-		txType, _ := nextTxType()
+	for i := 0; it.Next() && !incomplete; i++ {
+		txType, end := nextTxType()
+		if end {
+			return nil, false, fmt.Errorf("block has less txs than receipts (%d)", i)
+		}
+		// Skip receipts before the requested index.
+		if uint64(i) < q.firstIndex {
+			continue
+		}
 		content, _, _ := rlp.SplitList(it.Value())
+		// Stop appending receipts when they would go over the size limit.
+		// Note we rely on the assumption that the txType is encoded as a single byte,
+		// which is always true because EIP-2718 does not allow tx types > 0x7f.
+		size := rlp.ListSize(1 + uint64(len(content)))
+		if q.sizeLimit > 0 && (uint64(enc.Size())+size) > q.sizeLimit {
+			break
+		}
+
 		receiptList := enc.List()
 		enc.WriteUint64(uint64(txType))
 		enc.Write(content)
@@ -266,7 +286,7 @@ func blockReceiptsToNetwork(blockReceipts, blockBody rlp.RawValue) ([]byte, erro
 	}
 	enc.ListEnd(outer)
 	enc.Flush()
-	return out.Bytes(), nil
+	return out.Bytes(), incomplete, nil
 }
 
 // txTypesInBody parses the transactions list of an encoded block body, returning just the types.

eth/protocols/eth/receipt_test.go

@@ -105,10 +105,13 @@ func TestReceiptList(t *testing.T) {
 		canonBody, _ := rlp.EncodeToBytes(blockBody)
 
 		// convert from storage encoding to network encoding
-		network, err := blockReceiptsToNetwork(canonDB, canonBody)
+		network, incomplete, err := blockReceiptsToNetwork(canonDB, canonBody, receiptQueryParams{})
 		if err != nil {
 			t.Fatalf("test[%d]: blockReceiptsToNetwork error: %v", i, err)
 		}
+		if incomplete {
+			t.Fatalf("test[%d]: blockReceiptsToNetwork returned incomplete == true", i)
+		}
 
 		// parse as Receipts response list from network encoding
 		var rl ReceiptList