removed buf from mysqlConn

Author: Brigitte Lamarche

benchmark_test.go

@@ -205,7 +205,7 @@ func BenchmarkRoundtripBin(b *testing.B) {
 			length = max
 		}
 		test := sample[0:length]
-		rows := tb.checkRows(stmt.Query(test))
+		rows := tb.checkRows(stmt.Query(test)) //run benchmark tests to test that bit of code
 		if !rows.Next() {
 			rows.Close()
 			b.Fatalf("crashed")
@@ -232,9 +232,9 @@ func BenchmarkInterpolation(b *testing.B) {
 		maxAllowedPacket: maxPacketSize,
 		maxWriteSize:     maxPacketSize - 1,
 	}
-	
+
 	buf := newBuffer(nil)
-	mc.reader = newSimpleReader(&buf)
+	mc.reader = &buf
 
 	args := []driver.Value{
 		int64(42424242),

buffer.go

@@ -21,7 +21,7 @@ const defaultBufSize = 4096
 // In other words, we can't write and read simultaneously on the same connection.
 // The buffer is similar to bufio.Reader / Writer but zero-copy-ish
 // Also highly optimized for this particular use case.
-type buffer struct { //PROBLEM: figure this all out better
+type buffer struct {
 	buf     []byte
 	nc      net.Conn
 	idx     int
@@ -49,7 +49,7 @@ func (b *buffer) fill(need int) error {
 	// grow buffer if necessary
 	// TODO: let the buffer shrink again at some point
 	//       Maybe keep the org buf slice and swap back?
-	if need > len(b.buf) { //look up what len and cap mean again!
+	if need > len(b.buf) {
 		// Round up to the next multiple of the default size
 		newBuf := make([]byte, ((need/defaultBufSize)+1)*defaultBufSize)
 		copy(newBuf, b.buf)
@@ -92,10 +92,6 @@ func (b *buffer) fill(need int) error {
 // returns next N bytes from buffer.
 // The returned slice is only guaranteed to be valid until the next read
 func (b *buffer) readNext(need int) ([]byte, error) {
-	if need == -1 {
-		return b.takeCompleteBuffer()
-	}
-
 	if b.length < need {
 		// refill
 		if err := b.fill(need); err != nil {
@@ -113,8 +109,12 @@ func (b *buffer) readNext(need int) ([]byte, error) {
 // If possible, a slice from the existing buffer is returned.
 // Otherwise a bigger buffer is made.
 // Only one buffer (total) can be used at a time.
-func (b *buffer) takeBuffer(length int) []byte {
-	if b.length > 0 { //assume its empty
+func (b *buffer) reuseBuffer(length int) []byte {
+	if length == -1 {
+		return b.takeCompleteBuffer()
+	}
+
+	if b.length > 0 {
 		return nil
 	}
 
@@ -130,18 +130,6 @@ func (b *buffer) takeBuffer(length int) []byte {
 	return make([]byte, length)
 }
 
-/*
-// shortcut which can be used if the requested buffer is guaranteed to be
-// smaller than defaultBufSize
-// Only one buffer (total) can be used at a time.
-func (b *buffer) takeSmallBuffer(length int) []byte {
-	if b.length == 0 { //assume its empty 
-		return b.buf[:length]
-	}
-	return nil
-}
-*/
-
 // takeCompleteBuffer returns the complete existing buffer.
 // This can be used if the necessary buffer size is unknown.
 // Only one buffer (total) can be used at a time.

compress.go

@@ -11,37 +11,26 @@ const (
 )
 
 type compressedReader struct {
-	buf      *buffer //packetReader
+	buf      packetReader
 	bytesBuf []byte
 	mc       *mysqlConn
 	zr       io.ReadCloser
 }
 
-
-type simpleReader struct {
-	buf      *buffer //packetReader
-}
-
 type compressedWriter struct {
 	connWriter io.Writer
 	mc         *mysqlConn
 	zw         *zlib.Writer
 }
 
-func newCompressedReader(buf *buffer, mc *mysqlConn) *compressedReader {
+func newCompressedReader(buf packetReader, mc *mysqlConn) *compressedReader {
 	return &compressedReader{
 		buf:      buf,
 		bytesBuf: make([]byte, 0),
 		mc:       mc,
 	}
 }
 
-func newSimpleReader(buf *buffer) *simpleReader {
-	return &simpleReader{
-		buf:      buf,
-	}
-}
-
 func newCompressedWriter(connWriter io.Writer, mc *mysqlConn) *compressedWriter {
 	return &compressedWriter{
 		connWriter: connWriter,
@@ -63,8 +52,8 @@ func (cr *compressedReader) readNext(need int) ([]byte, error) {
 	return data, nil
 }
 
-func (sr *simpleReader) readNext(need int) ([]byte, error) {
-	return sr.buf.readNext(need)
+func (cr *compressedReader) reuseBuffer(length int) []byte {
+	return cr.buf.reuseBuffer(length)
 }
 
 func (cr *compressedReader) uncompressPacket() error {

compress_test.go

@@ -39,6 +39,10 @@ func (mb *mockBuf) readNext(need int) ([]byte, error) {
 	return data, nil
 }
 
+func (mb *mockBuf) reuseBuffer(length int) []byte {
+	return make([]byte, length) //just give them a new buffer
+}
+
 // compressHelper compresses uncompressedPacket and checks state variables
 func compressHelper(t *testing.T, mc *mysqlConn, uncompressedPacket []byte) []byte {
 	// get status variables

connection.go

@@ -54,20 +54,9 @@ type mysqlConn struct {
 
 type packetReader interface {
 	readNext(need int) ([]byte, error)
+	reuseBuffer(length int) []byte
 }
 
-/*
-type packetReadCloser interface{
-	Read(n int) ([]byte, error)
-	Close() error // PROBLEM: is there a way to do this?
-}
-
-type packetWriteCloser interface{
-	Write([]byte) (int, error)
-	Close() error
-}
-*/ 
-
 // Handles parameters set in DSN after the connection is established
 func (mc *mysqlConn) handleParams() (err error) {
 	for param, val := range mc.cfg.Params {
@@ -208,10 +197,7 @@ func (mc *mysqlConn) interpolateParams(query string, args []driver.Value) (strin
 		return "", driver.ErrSkip
 	}
 
-	//https://stackoverflow.com/questions/29684609/how-to-check-if-an-object-has-a-particular-method
-
-	//reader has &buf which is a packetreader but also always a buffer
-	buf, _ := mc.reader.readNext(-1) //PROBLEM uncompressed so this works, what if compressed
+	buf := mc.reader.reuseBuffer(-1)
 
 	if buf == nil {
 		// can not take the buffer. Something must be wrong with the connection

connection_test.go

@@ -21,7 +21,7 @@ func TestInterpolateParams(t *testing.T) {
 		},
 	}
 	buf := newBuffer(nil)
-	mc.reader = newSimpleReader(&buf)
+	mc.reader = &buf
 
 	q, err := mc.interpolateParams("SELECT ?+?", []driver.Value{int64(42), "gopher"})
 	if err != nil {
@@ -42,7 +42,7 @@ func TestInterpolateParamsTooManyPlaceholders(t *testing.T) {
 		},
 	}
 	buf := newBuffer(nil)
-	mc.reader = newSimpleReader(&buf)
+	mc.reader = &buf
 
 	q, err := mc.interpolateParams("SELECT ?+?", []driver.Value{int64(42)})
 	if err != driver.ErrSkip {
@@ -61,7 +61,7 @@ func TestInterpolateParamsPlaceholderInString(t *testing.T) {
 	}
 
 	buf := newBuffer(nil)
-	mc.reader = newSimpleReader(&buf)
+	mc.reader = &buf
 
 	q, err := mc.interpolateParams("SELECT 'abc?xyz',?", []driver.Value{int64(42)})
 	// When InterpolateParams support string literal, this should return `"SELECT 'abc?xyz', 42`

driver.go

@@ -98,10 +98,9 @@ func (d MySQLDriver) Open(dsn string) (driver.Conn, error) {
 	mc.writeTimeout = mc.cfg.WriteTimeout
 
 	// packet reader and writer in handshake are never compressed
-	mc.reader = newSimpleReader(&buf)
+	mc.reader = &buf
 	mc.writer = mc.netConn
 
-
 	// Reading Handshake Initialization Packet
 	cipher, err := mc.readInitPacket()
 	if err != nil {

packets.go

@@ -28,7 +28,7 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 	var prevData []byte
 	for {
 		// read packet header
-		data, err := mc.reader.readNext(4) 
+		data, err := mc.reader.readNext(4)
 		if err != nil {
 			if cerr := mc.canceled.Value(); cerr != nil {
 				return nil, cerr
@@ -64,7 +64,7 @@ func (mc *mysqlConn) readPacket() ([]byte, error) {
 		}
 
 		// read packet body [pktLen bytes]
-		data, err = mc.reader.readNext(pktLen) 
+		data, err = mc.reader.readNext(pktLen)
 		if err != nil {
 			if cerr := mc.canceled.Value(); cerr != nil {
 				return nil, cerr
@@ -283,8 +283,8 @@ func (mc *mysqlConn) writeAuthPacket(cipher []byte) error {
 	}
 
 	// Calculate packet length and get buffer with that size
-	data, _ := mc.reader.readNext(pktLen + 4)
-	
+	data := mc.reader.reuseBuffer(pktLen + 4)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -329,10 +329,9 @@ func (mc *mysqlConn) writeAuthPacket(cipher []byte) error {
 		mc.netConn = tlsConn
 		nc := tlsConn
 
-		// make newBuffer with tls conn, clean slate bc handshake 
 		newBuf := newBuffer(nc)
-		mc.reader = newSimpleReader(&newBuf)
-		
+		mc.reader = &newBuf
+
 		mc.writer = mc.netConn
 	}
 
@@ -378,7 +377,7 @@ func (mc *mysqlConn) writeOldAuthPacket(cipher []byte) error {
 
 	// Calculate the packet length and add a tailing 0
 	pktLen := len(scrambleBuff) + 1
-	data, _ := mc.reader.readNext(4 + pktLen) 
+	data := mc.reader.reuseBuffer(4 + pktLen)
 
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
@@ -398,8 +397,8 @@ func (mc *mysqlConn) writeOldAuthPacket(cipher []byte) error {
 func (mc *mysqlConn) writeClearAuthPacket() error {
 	// Calculate the packet length and add a tailing 0
 	pktLen := len(mc.cfg.Passwd) + 1
-	data, _ := mc.reader.readNext(4 + pktLen)
-	
+	data := mc.reader.reuseBuffer(4 + pktLen)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -422,8 +421,8 @@ func (mc *mysqlConn) writeNativeAuthPacket(cipher []byte) error {
 
 	// Calculate the packet length and add a tailing 0
 	pktLen := len(scrambleBuff)
-	data, _ := mc.reader.readNext(4 + pktLen)
-	
+	data := mc.reader.reuseBuffer(4 + pktLen)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -445,8 +444,8 @@ func (mc *mysqlConn) writeCommandPacket(command byte) error {
 	mc.sequence = 0
 	mc.compressionSequence = 0
 
-	data, _ := mc.reader.readNext(4+1)
-	
+	data := mc.reader.reuseBuffer(4 + 1)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -466,8 +465,8 @@ func (mc *mysqlConn) writeCommandPacketStr(command byte, arg string) error {
 	mc.compressionSequence = 0
 
 	pktLen := 1 + len(arg)
-	data, _ := mc.reader.readNext(pktLen + 4)
-	
+	data := mc.reader.reuseBuffer(pktLen + 4)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -489,8 +488,8 @@ func (mc *mysqlConn) writeCommandPacketUint32(command byte, arg uint32) error {
 	mc.sequence = 0
 	mc.compressionSequence = 0
 
-	data, _ := mc.reader.readNext(4 + 1 + 4)
-	
+	data := mc.reader.reuseBuffer(4 + 1 + 4)
+
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
 		errLog.Print(ErrBusyBuffer)
@@ -957,9 +956,10 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 	var data []byte
 
 	if len(args) == 0 {
-		data, _ = mc.reader.readNext(minPktLen)
+		data = mc.reader.reuseBuffer(minPktLen)
+
 	} else {
-		data, _ = mc.reader.readNext(-1) //how does this work out with compressed?
+		data = mc.reader.reuseBuffer(-1)
 	}
 	if data == nil {
 		// can not take the buffer. Something must be wrong with the connection
@@ -1138,8 +1138,10 @@ func (stmt *mysqlStmt) writeExecutePacket(args []driver.Value) error {
 		// In that case we must build the data packet with the new values buffer
 		if valuesCap != cap(paramValues) {
 			data = append(data[:pos], paramValues...)
-			readerBuffer := mc.reader.getBuffer() //PROBLEM: what the fuck is going on here??
-			readerBuffer.buf = data
+
+			bufBuf := mc.reader.reuseBuffer(-1)
+			bufBuf = data
+			fmt.Println(bufBuf) //dont know how to make it compile w/o some op here on bufBuf
 		}
 
 		pos += len(paramValues)