Implement tlb.Transaction.SourceBoc()

boc/boc.go

@@ -315,7 +315,7 @@ func newBagOfCells() *bagOfCells {
 	}
 }
 
-// serializeBoc converts the given list of root cells to a byte representation.
+// SerializeBoc converts the given list of root cells to a byte representation.
 //
 //	serialized_boc#672fb0ac has_idx:(## 1) has_crc32c:(## 1)
 //	has_cache_bits:(## 1) flags:(## 2) { flags = 0 }
@@ -327,7 +327,7 @@ func newBagOfCells() *bagOfCells {
 //	tot_cells_size:(##(off_bytes * 8))
 //	index:(cells * ##(off_bytes * 8))
 //	cell_data:(tot_cells_size * [ uint8 ])
-//	= BagOfCells;
+//	= bagOfCells;
 func (boc *bagOfCells) serializeBoc(rootCells []*Cell, idx bool, hasCrc32 bool, cacheBits bool, flags uint) ([]byte, error) {
 	roots, cellInfos, err := boc.importRoots(rootCells)
 	if err != nil {

boc/cell.go

@@ -132,6 +132,13 @@ func (c *Cell) ToBocCustom(idx bool, hasCrc32 bool, cacheBits bool, flags uint)
 	return bag.serializeBoc([]*Cell{c}, idx, hasCrc32, cacheBits, 0)
 }
 
+func (c *Cell) ToBocCustomWithHasher(hasher *Hasher, idx bool, hasCrc32 bool, cacheBits bool, flags uint) ([]byte, error) {
+	bag := &bagOfCells{
+		hasher: hasher,
+	}
+	return bag.serializeBoc([]*Cell{c}, idx, hasCrc32, cacheBits, 0)
+}
+
 func (c *Cell) ToBocStringCustom(idx bool, hasCrc32 bool, cacheBits bool, flags uint) (string, error) {
 	boc, err := c.ToBocCustom(idx, hasCrc32, cacheBits, flags)
 	if err != nil {

tlb/benchmark_test.go

@@ -44,4 +44,11 @@ func Test_block(b *testing.T) {
 	if err != nil {
 		b.Errorf("Unmarshal() failed: %v", err)
 	}
+
+	for _, tx := range block.AllTransactions() {
+		_, err := tx.SourceBoc()
+		if err != nil {
+			b.Errorf("SourceBoc() failed: %v", err)
+		}
+	}
 }

tlb/decoder.go

@@ -294,5 +294,4 @@ func decodeBitString(c *boc.Cell, val reflect.Value) error {
 // Hasher returns boc.Hasher that is used to calculate hashes when decoding.
 func (dec *Decoder) Hasher() *boc.Hasher {
 	return dec.hasher
-
 }

tlb/transactions.go

@@ -33,21 +33,40 @@ type Transaction struct {
 	Description TransactionDescr `tlb:"^"`
 
 	hash Bits256
+
+	lazySourceBoc func() ([]byte, error)
 }
 
 // Hash returns a hash of this transaction.
 func (tx *Transaction) Hash() Bits256 {
 	return tx.hash
 }
 
+// SourceBoc returns a BOC of this transaction.
+// It works only if the transaction was unmarshalled from a cell.
+func (tx *Transaction) SourceBoc() ([]byte, error) {
+	if tx.lazySourceBoc != nil {
+		return tx.lazySourceBoc()
+	}
+	return nil, fmt.Errorf("transaction was not unmarshalled from cell")
+}
+
 func (tx *Transaction) UnmarshalTLB(c *boc.Cell, decoder *Decoder) error {
 	var (
 		hash []byte
 		err  error
 	)
 	if decoder.hasher != nil {
+		tx.lazySourceBoc = func() ([]byte, error) {
+			c.ResetCounters()
+			return c.ToBocCustomWithHasher(decoder.Hasher(), false, false, false, 0)
+		}
 		hash, err = decoder.hasher.Hash(c)
 	} else {
+		tx.lazySourceBoc = func() ([]byte, error) {
+			c.ResetCounters()
+			return boc.SerializeBoc(c, false, false, false, 0)
+		}
 		hash, err = c.Hash()
 	}
 	if err != nil {