app-init

internal/mysqlserver/conn.go

@@ -0,0 +1,105 @@
+package mysqlserver
+
+import (
+	"fmt"
+	"io"
+	"net"
+	"time"
+)
+
+type packetConn struct {
+	c      net.Conn
+	seq    uint8
+	max    int
+	readTO time.Duration
+	writeTO time.Duration
+}
+
+func newPacketConn(c net.Conn, timeout time.Duration) *packetConn {
+	return &packetConn{c: c, max: MaxPacketSize, readTO: timeout, writeTO: timeout}
+}
+
+func (p *packetConn) resetSeq() { p.seq = 0 }
+
+func (p *packetConn) readPacket() ([]byte, error) {
+	var payload []byte
+	for {
+		if p.readTO > 0 {
+			_ = p.c.SetReadDeadline(time.Now().Add(p.readTO))
+		}
+		var hdr [4]byte
+		if _, err := io.ReadFull(p.c, hdr[:]); err != nil {
+			return nil, err
+		}
+		n := int(readU24(hdr[:3]))
+		seq := hdr[3]
+		if seq != p.seq {
+			return nil, fmt.Errorf("sequence mismatch: got %d want %d", seq, p.seq)
+		}
+		p.seq++
+		if n == 0 {
+			return payload, nil
+		}
+		if n > p.max {
+			return nil, fmt.Errorf("packet too large: %d", n)
+		}
+		chunk := make([]byte, n)
+		if _, err := io.ReadFull(p.c, chunk); err != nil {
+			return nil, err
+		}
+		payload = append(payload, chunk...)
+		if n < 0xffffff {
+			return payload, nil
+		}
+	}
+}
+
+func (p *packetConn) writePacket(payload []byte) error {
+	off := 0
+	for {
+		n := len(payload) - off
+		if n > 0xffffff {
+			n = 0xffffff
+		}
+		var hdr [4]byte
+		hdr[0] = byte(n)
+		hdr[1] = byte(n >> 8)
+		hdr[2] = byte(n >> 16)
+		hdr[3] = p.seq
+		p.seq++
+		if p.writeTO > 0 {
+			_ = p.c.SetWriteDeadline(time.Now().Add(p.writeTO))
+		}
+		if _, err := p.c.Write(hdr[:]); err != nil {
+			return err
+		}
+		if n > 0 {
+			if _, err := p.c.Write(payload[off : off+n]); err != nil {
+				return err
+			}
+		}
+		off += n
+		if n < 0xffffff {
+			return nil
+		}
+	}
+}
+
+func (p *packetConn) writeOK(affected, lastInsertID uint64, status, warnings uint16) error {
+	return p.writePacket(encodeOK(affected, lastInsertID, status, warnings))
+}
+
+func (p *packetConn) writeERR(errno uint16, msg string) error {
+	return p.writePacket(encodeERR(errno, msg))
+}
+
+func (p *packetConn) remote() string {
+	if p.c.RemoteAddr() == nil {
+		return ""
+	}
+	return p.c.RemoteAddr().String()
+}
+
+func (p *packetConn) close() error {
+	return p.c.Close()
+}