Merge pull request #170 from cxmcc/minor

Replace recursive approach with iterative approach for readPacket()

packets.go

@@ -24,54 +24,56 @@ import (
 
 // Read packet to buffer 'data'
 func (mc *mysqlConn) readPacket() ([]byte, error) {
-	// Read packet header
-	data, err := mc.buf.readNext(4)
-	if err != nil {
-		errLog.Print(err.Error())
-		mc.Close()
-		return nil, driver.ErrBadConn
-	}
+	var payload []byte
+	for {
+		// Read packet header
+		data, err := mc.buf.readNext(4)
+		if err != nil {
+			errLog.Print(err.Error())
+			mc.Close()
+			return nil, driver.ErrBadConn
+		}
 
-	// Packet Length [24 bit]
-	pktLen := int(uint32(data[0]) | uint32(data[1])<<8 | uint32(data[2])<<16)
+		// Packet Length [24 bit]
+		pktLen := int(uint32(data[0]) | uint32(data[1])<<8 | uint32(data[2])<<16)
 
-	if pktLen < 1 {
-		errLog.Print(errMalformPkt.Error())
-		mc.Close()
-		return nil, driver.ErrBadConn
-	}
+		if pktLen < 1 {
+			errLog.Print(errMalformPkt.Error())
+			mc.Close()
+			return nil, driver.ErrBadConn
+		}
 
-	// Check Packet Sync [8 bit]
-	if data[3] != mc.sequence {
-		if data[3] > mc.sequence {
-			return nil, errPktSyncMul
-		} else {
-			return nil, errPktSync
+		// Check Packet Sync [8 bit]
+		if data[3] != mc.sequence {
+			if data[3] > mc.sequence {
+				return nil, errPktSyncMul
+			} else {
+				return nil, errPktSync
+			}
 		}
-	}
-	mc.sequence++
+		mc.sequence++
+
+		// Read packet body [pktLen bytes]
+		data, err = mc.buf.readNext(pktLen)
+		if err != nil {
+			errLog.Print(err.Error())
+			mc.Close()
+			return nil, driver.ErrBadConn
+		}
+
+		isLastPacket := (pktLen < maxPacketSize)
 
-	// Read packet body [pktLen bytes]
-	if data, err = mc.buf.readNext(pktLen); err == nil {
-		if pktLen < maxPacketSize {
+		// Zero allocations for non-splitting packets
+		if isLastPacket && payload == nil {
 			return data, nil
 		}
 
-		// Make a copy since data becomes invalid with the next read
-		buf := make([]byte, len(data))
-		copy(buf, data)
+		payload = append(payload, data...)
 
-		// More data
-		data, err = mc.readPacket()
-		if err == nil {
-			return append(buf, data...), nil
+		if isLastPacket {
+			return payload, nil
 		}
 	}
-
-	// err case
-	mc.Close()
-	errLog.Print(err.Error())
-	return nil, driver.ErrBadConn
 }
 
 // Write packet buffer 'data'