code cleanup

x/mongo/driver/topology/connection.go

@@ -79,9 +79,9 @@ type connection struct {
 	driverConnectionID uint64
 	generation         uint64
 
-	// awaitingResponse indicates the size of server response that was not completely
+	// awaitRemainingBytes indicates the size of server response that was not completely
 	// read before returning the connection to the pool.
-	awaitingResponse *int32
+	awaitRemainingBytes *int32
 
 	// oidcTokenGenID is the monotonic generation ID for OIDC tokens, used to invalidate
 	// accessTokens in the OIDC authenticator cache.
@@ -115,12 +115,6 @@ func newConnection(addr address.Address, opts ...ConnectionOption) *connection {
 	return c
 }
 
-// DriverConnectionID returns the driver connection ID.
-// TODO(GODRIVER-2824): change return type to int64.
-func (c *connection) DriverConnectionID() uint64 {
-	return c.driverConnectionID
-}
-
 // setGenerationNumber sets the connection's generation number if a callback has been provided to do so in connection
 // configuration.
 func (c *connection) setGenerationNumber() {
@@ -142,6 +136,39 @@ func (c *connection) hasGenerationNumber() bool {
 	return c.desc.LoadBalanced()
 }
 
+func configureTLS(ctx context.Context,
+	tlsConnSource tlsConnectionSource,
+	nc net.Conn,
+	addr address.Address,
+	config *tls.Config,
+	ocspOpts *ocsp.VerifyOptions,
+) (net.Conn, error) {
+	// Ensure config.ServerName is always set for SNI.
+	if config.ServerName == "" {
+		hostname := addr.String()
+		colonPos := strings.LastIndex(hostname, ":")
+		if colonPos == -1 {
+			colonPos = len(hostname)
+		}
+
+		hostname = hostname[:colonPos]
+		config.ServerName = hostname
+	}
+
+	client := tlsConnSource.Client(nc, config)
+	if err := clientHandshake(ctx, client); err != nil {
+		return nil, err
+	}
+
+	// Only do OCSP verification if TLS verification is requested.
+	if !config.InsecureSkipVerify {
+		if ocspErr := ocsp.Verify(ctx, client.ConnectionState(), ocspOpts); ocspErr != nil {
+			return nil, ocspErr
+		}
+	}
+	return client, nil
+}
+
 // connect handles the I/O for a connection. It will dial, configure TLS, and perform initialization
 // handshakes. All errors returned by connect are considered "before the handshake completes" and
 // must be handled by calling the appropriate SDAM handshake error handler.
@@ -317,6 +344,10 @@ func (c *connection) closeConnectContext() {
 	}
 }
 
+func (c *connection) cancellationListenerCallback() {
+	_ = c.close()
+}
+
 func transformNetworkError(ctx context.Context, originalError error, contextDeadlineUsed bool) error {
 	if originalError == nil {
 		return nil
@@ -339,10 +370,6 @@ func transformNetworkError(ctx context.Context, originalError error, contextDead
 	return originalError
 }
 
-func (c *connection) cancellationListenerCallback() {
-	_ = c.close()
-}
-
 func (c *connection) writeWireMessage(ctx context.Context, wm []byte) error {
 	var err error
 	if atomic.LoadInt64(&c.state) != connConnected {
@@ -423,7 +450,7 @@ func (c *connection) readWireMessage(ctx context.Context) ([]byte, error) {
 
 	dst, errMsg, err := c.read(ctx)
 	if err != nil {
-		if c.awaitingResponse == nil {
+		if c.awaitRemainingBytes == nil {
 			// If the connection was not marked as awaiting response, use the
 			// pre-CSOT behavior and close the connection because we don't know
 			// if there are other bytes left to read.
@@ -443,6 +470,29 @@ func (c *connection) readWireMessage(ctx context.Context) ([]byte, error) {
 	return dst, nil
 }
 
+func (c *connection) parseWmSizeBytes(wmSizeBytes [4]byte) (int32, error) {
+	// read the length as an int32
+	size := (int32(wmSizeBytes[0])) |
+		(int32(wmSizeBytes[1]) << 8) |
+		(int32(wmSizeBytes[2]) << 16) |
+		(int32(wmSizeBytes[3]) << 24)
+
+	if size < 4 {
+		return 0, fmt.Errorf("malformed message length: %d", size)
+	}
+	// In the case of a hello response where MaxMessageSize has not yet been set, use the hard-coded
+	// defaultMaxMessageSize instead.
+	maxMessageSize := c.desc.MaxMessageSize
+	if maxMessageSize == 0 {
+		maxMessageSize = defaultMaxMessageSize
+	}
+	if uint32(size) > maxMessageSize {
+		return 0, errResponseTooLarge
+	}
+
+	return size, nil
+}
+
 func (c *connection) read(ctx context.Context) (bytesRead []byte, errMsg string, err error) {
 	go c.cancellationListener.Listen(ctx, c.cancellationListenerCallback)
 	defer func() {
@@ -475,35 +525,23 @@ func (c *connection) read(ctx context.Context) (bytesRead []byte, errMsg string,
 	n, err := io.ReadFull(c.nc, sizeBuf[:])
 	if err != nil {
 		if l := int32(n); l == 0 && needToWait(err) {
-			c.awaitingResponse = &l
+			c.awaitRemainingBytes = &l
 		}
 		return nil, "incomplete read of message header", err
 	}
-
-	// read the length as an int32
-	size := (int32(sizeBuf[0])) | (int32(sizeBuf[1]) << 8) | (int32(sizeBuf[2]) << 16) | (int32(sizeBuf[3]) << 24)
-
-	if size < 4 {
-		err = fmt.Errorf("malformed message length: %d", size)
+	size, err := c.parseWmSizeBytes(sizeBuf)
+	if err != nil {
 		return nil, err.Error(), err
 	}
-	// In the case of a hello response where MaxMessageSize has not yet been set, use the hard-coded
-	// defaultMaxMessageSize instead.
-	maxMessageSize := c.desc.MaxMessageSize
-	if maxMessageSize == 0 {
-		maxMessageSize = defaultMaxMessageSize
-	}
-	if uint32(size) > maxMessageSize {
-		return nil, errResponseTooLarge.Error(), errResponseTooLarge
-	}
 
 	dst := make([]byte, size)
 	copy(dst, sizeBuf[:])
 
 	n, err = io.ReadFull(c.nc, dst[4:])
 	if err != nil {
-		if l := size - 4 - int32(n); l > 0 && needToWait(err) {
-			c.awaitingResponse = &l
+		remainingBytes := size - 4 - int32(n)
+		if remainingBytes > 0 && needToWait(err) {
+			c.awaitRemainingBytes = &remainingBytes
 		}
 		return dst, "incomplete read of full message", err
 	}
@@ -551,10 +589,6 @@ func (c *connection) setCanStream(canStream bool) {
 	c.canStream = canStream
 }
 
-func (c initConnection) supportsStreaming() bool {
-	return c.canStream
-}
-
 func (c *connection) setStreaming(streaming bool) {
 	c.currentlyStreaming = streaming
 }
@@ -568,6 +602,12 @@ func (c *connection) setSocketTimeout(timeout time.Duration) {
 	c.writeTimeout = timeout
 }
 
+// DriverConnectionID returns the driver connection ID.
+// TODO(GODRIVER-2824): change return type to int64.
+func (c *connection) DriverConnectionID() uint64 {
+	return c.driverConnectionID
+}
+
 func (c *connection) ID() string {
 	return c.id
 }
@@ -576,6 +616,14 @@ func (c *connection) ServerConnectionID() *int64 {
 	return c.serverConnectionID
 }
 
+func (c *connection) OIDCTokenGenID() uint64 {
+	return c.oidcTokenGenID
+}
+
+func (c *connection) SetOIDCTokenGenID(genID uint64) {
+	c.oidcTokenGenID = genID
+}
+
 // initConnection is an adapter used during connection initialization. It has the minimum
 // functionality necessary to implement the driver.Connection interface, which is required to pass a
 // *connection to a Handshaker.
@@ -613,7 +661,7 @@ func (c initConnection) CurrentlyStreaming() bool {
 	return c.getCurrentlyStreaming()
 }
 func (c initConnection) SupportsStreaming() bool {
-	return c.supportsStreaming()
+	return c.canStream
 }
 
 // Connection implements the driver.Connection interface to allow reading and writing wire
@@ -847,39 +895,6 @@ func (c *Connection) DriverConnectionID() uint64 {
 	return c.connection.DriverConnectionID()
 }
 
-func configureTLS(ctx context.Context,
-	tlsConnSource tlsConnectionSource,
-	nc net.Conn,
-	addr address.Address,
-	config *tls.Config,
-	ocspOpts *ocsp.VerifyOptions,
-) (net.Conn, error) {
-	// Ensure config.ServerName is always set for SNI.
-	if config.ServerName == "" {
-		hostname := addr.String()
-		colonPos := strings.LastIndex(hostname, ":")
-		if colonPos == -1 {
-			colonPos = len(hostname)
-		}
-
-		hostname = hostname[:colonPos]
-		config.ServerName = hostname
-	}
-
-	client := tlsConnSource.Client(nc, config)
-	if err := clientHandshake(ctx, client); err != nil {
-		return nil, err
-	}
-
-	// Only do OCSP verification if TLS verification is requested.
-	if !config.InsecureSkipVerify {
-		if ocspErr := ocsp.Verify(ctx, client.ConnectionState(), ocspOpts); ocspErr != nil {
-			return nil, ocspErr
-		}
-	}
-	return client, nil
-}
-
 // OIDCTokenGenID returns the OIDC token generation ID.
 func (c *Connection) OIDCTokenGenID() uint64 {
 	return c.oidcTokenGenID
@@ -933,11 +948,3 @@ func (c *cancellListener) StopListening() bool {
 	c.done <- struct{}{}
 	return c.aborted
 }
-
-func (c *connection) OIDCTokenGenID() uint64 {
-	return c.oidcTokenGenID
-}
-
-func (c *connection) SetOIDCTokenGenID(genID uint64) {
-	c.oidcTokenGenID = genID
-}

x/mongo/driver/topology/pool.go

@@ -10,7 +10,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"sync"
 	"sync/atomic"
@@ -833,22 +832,13 @@ func bgRead(pool *pool, conn *connection, size int32) {
 			err = fmt.Errorf("error reading the message size: %w", err)
 			return
 		}
-		size = (int32(sizeBuf[0])) | (int32(sizeBuf[1]) << 8) | (int32(sizeBuf[2]) << 16) | (int32(sizeBuf[3]) << 24)
-		if size < 4 {
-			err = fmt.Errorf("malformed message length: %d", size)
-			return
-		}
-		maxMessageSize := conn.desc.MaxMessageSize
-		if maxMessageSize == 0 {
-			maxMessageSize = defaultMaxMessageSize
-		}
-		if uint32(size) > maxMessageSize {
-			err = errResponseTooLarge
+		size, err = conn.parseWmSizeBytes(sizeBuf)
+		if err != nil {
 			return
 		}
 		size -= 4
 	}
-	_, err = io.CopyN(ioutil.Discard, conn.nc, int64(size))
+	_, err = io.CopyN(io.Discard, conn.nc, int64(size))
 	if err != nil {
 		err = fmt.Errorf("error reading message of %d: %w", size, err)
 	}
@@ -901,9 +891,9 @@ func (p *pool) checkInNoEvent(conn *connection) error {
 	// means that connections in "awaiting response" state are checked in but
 	// not usable, which is not covered by the current pool events. We may need
 	// to add pool event information in the future to communicate that.
-	if conn.awaitingResponse != nil {
-		size := *conn.awaitingResponse
-		conn.awaitingResponse = nil
+	if conn.awaitRemainingBytes != nil {
+		size := *conn.awaitRemainingBytes
+		conn.awaitRemainingBytes = nil
 		go bgRead(p, conn, size)
 		return nil
 	}

x/mongo/driver/topology/pool_test.go

@@ -1197,7 +1197,7 @@ func TestPool(t *testing.T) {
 				`^connection\(.*\[-\d+\]\) incomplete read of message header: context deadline exceeded: read unix .*->\.\/test.sock: i\/o timeout$`,
 			)
 			assert.True(t, regex.MatchString(err.Error()), "mismatched err: %v", err)
-			assert.Nil(t, conn.awaitingResponse, "conn.awaitingResponse should be nil")
+			assert.Nil(t, conn.awaitRemainingBytes, "conn.awaitingResponse should be nil")
 			wg.Wait()
 			p.close(context.Background())
 			close(errCh)