Fix mem leak while calling transaction.GetName() (#97)

db.go

@@ -1787,9 +1787,6 @@ func (db *DB) DisableManualCompaction() {
 }
 
 // GetColumnFamilyMetadata returns the metadata of the default column family.
-//
-// Note that the caller is responsible to release the returned memory
-// using rocksdb_column_family_metadata_destroy.
 func (db *DB) GetColumnFamilyMetadata() (m *ColumnFamilyMetadata) {
 	if c := C.rocksdb_get_column_family_metadata(db.c); c != nil {
 		m = newColumnFamilyMetadata(c)
@@ -1798,9 +1795,6 @@ func (db *DB) GetColumnFamilyMetadata() (m *ColumnFamilyMetadata) {
 }
 
 // GetColumnFamilyMetadataCF returns the metadata of the specified column family.
-//
-// Note that the caller is responsible to release the returned memory
-// using rocksdb_column_family_metadata_destroy.
 func (db *DB) GetColumnFamilyMetadataCF(cf *ColumnFamilyHandle) (m *ColumnFamilyMetadata) {
 	if c := C.rocksdb_get_column_family_metadata_cf(db.c, cf.c); c != nil {
 		m = newColumnFamilyMetadata(c)

options.go

@@ -1511,9 +1511,9 @@ func (opts *Options) SetFIFOCompactionOptions(value *FIFOCompactionOptions) {
 
 // GetStatisticsString returns the statistics as a string.
 func (opts *Options) GetStatisticsString() (stats string) {
-	sString := C.rocksdb_options_statistics_get_string(opts.c)
-	stats = C.GoString(sString)
-	C.rocksdb_free(unsafe.Pointer(sString))
+	cValue := C.rocksdb_options_statistics_get_string(opts.c)
+	stats = C.GoString(cValue)
+	C.rocksdb_free(unsafe.Pointer(cValue))
 	return
 }
 

transaction.go

@@ -33,9 +33,9 @@ func (transaction *Transaction) SetName(name string) (err error) {
 
 // GetName of transaction.
 func (transaction *Transaction) GetName() string {
-	var nameSize C.size_t
-	name := C.rocksdb_transaction_get_name(transaction.c, &nameSize)
-	return C.GoString(name)
+	var len C.size_t
+	cValue := C.rocksdb_transaction_get_name(transaction.c, &len)
+	return toString(cValue, C.int(len))
 }
 
 // Prepare transaction.

util.go

@@ -75,3 +75,9 @@ func fromCError(cErr *C.char) (err error) {
 	}
 	return
 }
+
+func toString(cVal *C.char, len C.int) string {
+	s := C.GoStringN(cVal, C.int(len))
+	C.rocksdb_free(unsafe.Pointer(cVal))
+	return s
+}