From b0aff615e008d4dc2967a2423c6305a3a5fbc635 Mon Sep 17 00:00:00 2001
From: Sergey Matveev <stargrave@stargrave.org>
Date: Fri, 20 Dec 2019 13:59:19 +0300
Subject: [PATCH] Buffer SP packets marshaling

---
 doc/news.ru.texi |  4 ++++
 doc/news.texi    |  4 ++++
 src/sp.go        | 17 ++++++++++++-----
 3 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/doc/news.ru.texi b/doc/news.ru.texi
index 71c82d8..beb54fc 100644
--- a/doc/news.ru.texi
+++ b/doc/news.ru.texi
@@ -14,6 +14,10 @@
 @item
 Завершать все порождаемые в SP протоколе горутины, меньше утечек памяти.
 
+@item
+SP протокол порождает меньше вызовов записей (соответственно, и TCP
+пакетов) в сокет.
+
 @end itemize
 
 @node Релиз 5.2.1
diff --git a/doc/news.texi b/doc/news.texi
index 7c72540..3693d70 100644
--- a/doc/news.texi
+++ b/doc/news.texi
@@ -16,6 +16,10 @@ Fixed not occurring handshake messages padding.
 @item
 Finish all SP protocol related goroutines, less memory leak.
 
+@item
+SP protocol generates less socket write calls, thus generating less TCP
+packets.
+
 @end itemize
 
 @node Release 5.2.1
diff --git a/src/sp.go b/src/sp.go
index 9389cac..d2123ee 100644
--- a/src/sp.go
+++ b/src/sp.go
@@ -142,11 +142,10 @@ func init() {
 
 func MarshalSP(typ SPType, sp interface{}) []byte {
 	var buf bytes.Buffer
-	var err error
-	if _, err = xdr.Marshal(&buf, SPHead{typ}); err != nil {
+	if _, err := xdr.Marshal(&buf, SPHead{typ}); err != nil {
 		panic(err)
 	}
-	if _, err = xdr.Marshal(&buf, sp); err != nil {
+	if _, err := xdr.Marshal(&buf, sp); err != nil {
 		panic(err)
 	}
 	return buf.Bytes()
@@ -198,6 +197,7 @@ type SPState struct {
 	isDead         chan struct{}
 	listOnly       bool
 	onlyPkts       map[[32]byte]bool
+	writeSPBuf     bytes.Buffer
 	sync.RWMutex
 }
 
@@ -241,8 +241,15 @@ func (state *SPState) dirUnlock() {
 }
 
 func (state *SPState) WriteSP(dst io.Writer, payload []byte) error {
-	n, err := xdr.Marshal(dst, SPRaw{Magic: MagicNNCPLv1, Payload: payload})
-	if err == nil {
+	state.writeSPBuf.Reset()
+	n, err := xdr.Marshal(&state.writeSPBuf, SPRaw{
+		Magic:   MagicNNCPLv1,
+		Payload: payload,
+	})
+	if err != nil {
+		return err
+	}
+	if n, err = dst.Write(state.writeSPBuf.Bytes()); err == nil {
 		state.TxLastSeen = time.Now()
 		state.TxBytes += int64(n)
 	}
-- 
2.44.0