WIP: Support once-encoded messages with the replicated objects

Signed-off-by: Leonard Lyubich <[email protected]>

client/object_put.go

@@ -7,6 +7,7 @@ import (
 	"io"
 	"math"
 	"os"
+	"sync"
 
 	"github.com/nspcc-dev/neofs-api-go/v2/acl"
 	v2object "github.com/nspcc-dev/neofs-api-go/v2/object"
@@ -402,7 +403,45 @@ func (c *Client) ReplicateObject(ctx context.Context, src io.ReadSeeker, signer
 	return resp.err
 }
 
+func ShareReplicatedObject(src io.ReadSeeker) io.ReadSeeker {
+	return &sharedReplicationMessage{
+		rs: src,
+	}
+}
+
+type sharedReplicationMessage struct {
+	rs io.ReadSeeker
+
+	mtx sync.Mutex
+	msg []byte
+	err error
+}
+
+func (x *sharedReplicationMessage) Read(p []byte) (n int, err error) {
+	return x.rs.Read(p)
+}
+
+func (x *sharedReplicationMessage) Seek(offset int64, whence int) (int64, error) {
+	return x.rs.Seek(offset, whence)
+}
+
 func prepareReplicateMessage(src io.ReadSeeker, signer neofscrypto.Signer) ([]byte, error) {
+	srm, ok := src.(*sharedReplicationMessage)
+	if !ok {
+		return newReplicateMessage(src, signer)
+	}
+
+	srm.mtx.Lock()
+	defer srm.mtx.Unlock()
+
+	if srm.msg == nil && srm.err == nil {
+		srm.msg, srm.err = newReplicateMessage(src, signer)
+	}
+
+	return srm.msg, srm.err
+}
+
+func newReplicateMessage(src io.ReadSeeker, signer neofscrypto.Signer) ([]byte, error) {
 	var objSize int64
 	var err error
 	switch v := src.(type) {