Refactor, fixes to Circ Peek, start processor/parser

processor.go

@@ -0,0 +1,108 @@
+package mqtt
+
+import (
+	"encoding/binary"
+	"log"
+	"net"
+	"time"
+
+	"github.com/mochi-co/mqtt/packets"
+	"github.com/mochi-co/mqtt/processors/circ"
+)
+
+// Processor reads and writes bytes to a network connection.
+type Processor struct {
+
+	// Conn is the net.Conn used to establish the connection.
+	Conn net.Conn
+
+	// R is a reader for reading incoming bytes.
+	R *circ.Reader
+
+	// W is a writer for writing outgoing bytes.
+	W *circ.Writer
+
+	// FixedHeader is the FixedHeader from the last read packet.
+	FixedHeader packets.FixedHeader
+}
+
+// NewProcessor returns a new instance of Processor.
+func NewProcessor(c net.Conn, r *circ.Reader, w *circ.Writer) *Processor {
+	return &Processor{
+		Conn: c,
+		R:    r,
+		W:    w,
+	}
+}
+
+// RefreshDeadline refreshes the read/write deadline for the net.Conn connection.
+func (p *Processor) RefreshDeadline(keepalive uint16) {
+	if p.Conn != nil {
+		expiry := time.Duration(keepalive+(keepalive/2)) * time.Second
+		p.Conn.SetDeadline(time.Now().Add(expiry))
+	}
+}
+
+// ReadFixedHeader reads in the values of the next packet's fixed header.
+func (p *Processor) ReadFixedHeader(fh *packets.FixedHeader) error {
+
+	// Peek the maximum message type and flags, and length.
+	peeked, err := p.R.Peek(1)
+	if err != nil {
+		return err
+	}
+
+	log.Println("Peeked", peeked)
+
+	// Unpack message type and flags from byte 1.
+	err = fh.Decode(peeked[0])
+	if err != nil {
+
+		// @SPEC [MQTT-2.2.2-2]
+		// If invalid flags are received, the receiver MUST close the Network Connection.
+		return packets.ErrInvalidFlags
+	}
+
+	log.Printf("FH %+v\n", fh)
+
+	// The remaining length value can be up to 5 bytes. Peek through each byte
+	// looking for continue values, and if found increase the peek. Otherwise
+	// decode the bytes that were legit.
+	//p.fhBuffer = p.fhBuffer[:0]
+	buf := make([]byte, 0, 6)
+	i := 1
+	//var b int64 = 2
+	for b := int64(2); b < 6; b++ {
+		peeked, err = p.R.Peek(b)
+		if err != nil {
+			return err
+		}
+
+		// Add the byte to the length bytes slice.
+		buf = append(buf, peeked[i])
+
+		// If it's not a continuation flag, end here.
+		if peeked[i] < 128 {
+			break
+		}
+
+		// If i has reached 4 without a length terminator, throw a protocol violation.
+		i++
+		if i == 4 {
+			return packets.ErrOversizedLengthIndicator
+		}
+	}
+
+	// Calculate and store the remaining length.
+	rem, _ := binary.Uvarint(buf)
+	fh.Remaining = int(rem)
+
+	// Discard the number of used length bytes + first byte.
+	//p.R.Discard(b)
+
+	// Set the fixed header in the parser.
+	p.FixedHeader = *fh
+
+	return nil
+
+}