Initial commit

lib/wal/wal-send.go

@@ -0,0 +1,73 @@
+package wal
+
+import (
+	"encoding/binary"
+	"git.crumpington.com/public/jldb/lib/errs"
+	"net"
+	"time"
+)
+
+const (
+	msgTypeRec       = 8
+	msgTypeHeartbeat = 16
+	msgTypeError     = 32
+)
+
+func (wal *WAL) Send(conn net.Conn, timeout time.Duration) error {
+	defer conn.Close()
+
+	var (
+		seqNum           int64
+		heartbeatTimeout = timeout / 8
+	)
+
+	conn.SetReadDeadline(time.Now().Add(timeout))
+	if err := binary.Read(conn, binary.LittleEndian, &seqNum); err != nil {
+		return errs.IO.WithErr(err)
+	}
+	conn.SetReadDeadline(time.Time{})
+
+	it, err := wal.Iterator(seqNum)
+	if err != nil {
+		return err
+	}
+	defer it.Close()
+
+	for {
+		if it.Next(heartbeatTimeout) {
+			rec := it.Record()
+
+			conn.SetWriteDeadline(time.Now().Add(timeout))
+
+			if _, err := conn.Write([]byte{msgTypeRec}); err != nil {
+				return errs.IO.WithErr(err)
+			}
+
+			if _, err := rec.writeTo(conn); err != nil {
+				return err
+			}
+
+			continue
+		}
+
+		if it.Error() != nil {
+			conn.SetWriteDeadline(time.Now().Add(timeout))
+			if _, err := conn.Write([]byte{msgTypeError}); err != nil {
+				return errs.IO.WithErr(err)
+			}
+
+			err, ok := it.Error().(*errs.Error)
+			if !ok {
+				err = errs.Unexpected.WithErr(err)
+			}
+			err.Write(conn)
+			//			w.Flush()
+			return err
+		}
+
+		conn.SetWriteDeadline(time.Now().Add(timeout))
+		if _, err := conn.Write([]byte{msgTypeHeartbeat}); err != nil {
+			return errs.IO.WithErr(err)
+		}
+	}
+}