Initial QSfera import

Server/vendor/github.com/nats-io/nats-server/v2/server/sendq.go

@@ -0,0 +1,118 @@
+// Copyright 2020-2025 The NATS Authors
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package server
+
+import (
+	"strconv"
+	"sync"
+)
+
+type outMsg struct {
+	subj string
+	rply string
+	hdr  []byte
+	msg  []byte
+}
+
+type sendq struct {
+	mu sync.Mutex
+	q  *ipQueue[*outMsg]
+	s  *Server
+	a  *Account
+}
+
+func (s *Server) newSendQ(acc *Account) *sendq {
+	sq := &sendq{s: s, q: newIPQueue[*outMsg](s, "SendQ"), a: acc}
+	s.startGoRoutine(sq.internalLoop)
+	return sq
+}
+
+func (sq *sendq) internalLoop() {
+	sq.mu.Lock()
+	s, q := sq.s, sq.q
+	sq.mu.Unlock()
+
+	defer s.grWG.Done()
+
+	c := s.createInternalSystemClient()
+	c.registerWithAccount(sq.a)
+	c.noIcb = true
+
+	defer c.closeConnection(ClientClosed)
+
+	// To optimize for not converting a string to a []byte slice.
+	var (
+		subj [256]byte
+		rply [256]byte
+		szb  [10]byte
+		hdb  [10]byte
+		_msg [4096]byte
+		msg  = _msg[:0]
+	)
+
+	for s.isRunning() {
+		select {
+		case <-s.quitCh:
+			return
+		case <-q.ch:
+			pms := q.pop()
+			for _, pm := range pms {
+				c.pa.subject = append(subj[:0], pm.subj...)
+				c.pa.size = len(pm.msg) + len(pm.hdr)
+				c.pa.szb = append(szb[:0], strconv.Itoa(c.pa.size)...)
+				if len(pm.rply) > 0 {
+					c.pa.reply = append(rply[:0], pm.rply...)
+				} else {
+					c.pa.reply = nil
+				}
+				msg = msg[:0]
+				if len(pm.hdr) > 0 {
+					c.pa.hdr = len(pm.hdr)
+					c.pa.hdb = append(hdb[:0], strconv.Itoa(c.pa.hdr)...)
+					msg = append(msg, pm.hdr...)
+					msg = append(msg, pm.msg...)
+					msg = append(msg, _CRLF_...)
+				} else {
+					c.pa.hdr = -1
+					c.pa.hdb = nil
+					msg = append(msg, pm.msg...)
+					msg = append(msg, _CRLF_...)
+				}
+				c.processInboundClientMsg(msg)
+				c.pa.szb = nil
+				outMsgPool.Put(pm)
+			}
+			// TODO: should this be in the for-loop instead?
+			c.flushClients(0)
+			q.recycle(&pms)
+		}
+	}
+}
+
+var outMsgPool = sync.Pool{
+	New: func() any {
+		return &outMsg{}
+	},
+}
+
+func (sq *sendq) send(subj, rply string, hdr, msg []byte) {
+	if sq == nil {
+		return
+	}
+	out := outMsgPool.Get().(*outMsg)
+	out.subj, out.rply = subj, rply
+	out.hdr = append(out.hdr[:0], hdr...)
+	out.msg = append(out.msg[:0], msg...)
+	sq.q.push(out)
+}