chore: fix lint & rm unused zero copy code (#395)

Author: xiaost

connection_impl.go

@@ -27,8 +27,6 @@ import (
 type connState = int32
 
 const (
-	defaultZeroCopyTimeoutSec = 60
-
 	connStateNone         = 0
 	connStateConnected    = 1
 	connStateDisconnected = 2
@@ -39,21 +37,20 @@ type connection struct {
 	netFD
 	onEvent
 	locker
-	operator        *FDOperator
-	readTimeout     time.Duration
-	readTimer       *time.Timer
-	readTrigger     chan error
-	waitReadSize    int64
-	writeTimeout    time.Duration
-	writeTimer      *time.Timer
-	writeTrigger    chan error
-	inputBuffer     *LinkBuffer
-	outputBuffer    *LinkBuffer
-	outputBarrier   *barrier
-	supportZeroCopy bool
-	maxSize         int       // The maximum size of data between two Release().
-	bookSize        int       // The size of data that can be read at once.
-	state           connState // Connection state should be changed sequentially.
+	operator      *FDOperator
+	readTimeout   time.Duration
+	readTimer     *time.Timer
+	readTrigger   chan error
+	waitReadSize  int64
+	writeTimeout  time.Duration
+	writeTimer    *time.Timer
+	writeTrigger  chan error
+	inputBuffer   *LinkBuffer
+	outputBuffer  *LinkBuffer
+	outputBarrier *barrier
+	maxSize       int       // The maximum size of data between two Release().
+	bookSize      int       // The size of data that can be read at once.
+	state         connState // Connection state should be changed sequentially.
 }
 
 var (
@@ -351,10 +348,6 @@ func (c *connection) init(conn Conn, opts *options) (err error) {
 	case "tcp", "tcp4", "tcp6":
 		setTCPNoDelay(c.fd, true)
 	}
-	// check zero-copy
-	if setZeroCopy(c.fd) == nil && setBlockZeroCopySend(c.fd, defaultZeroCopyTimeoutSec, 0) == nil {
-		c.supportZeroCopy = true
-	}
 
 	// connection initialized and prepare options
 	return c.onPrepare(opts)
@@ -483,9 +476,8 @@ func (c *connection) flush() error {
 	if c.outputBuffer.IsEmpty() {
 		return nil
 	}
-	// TODO: Let the upper layer pass in whether to use ZeroCopy.
 	bs := c.outputBuffer.GetBytes(c.outputBarrier.bs)
-	n, err := sendmsg(c.fd, bs, c.outputBarrier.ivs, false && c.supportZeroCopy)
+	n, err := sendmsg(c.fd, bs, c.outputBarrier.ivs, false)
 	if err != nil && err != syscall.EAGAIN {
 		return Exception(err, "when flush")
 	}

connection_lock.go

@@ -59,11 +59,11 @@ type locker struct {
 }
 
 func (l *locker) closeBy(w who) (success bool) {
-	return atomic.CompareAndSwapInt32(&l.keychain[closing], 0, int32(w))
+	return atomic.CompareAndSwapInt32(&l.keychain[closing], 0, w)
 }
 
 func (l *locker) isCloseBy(w who) (yes bool) {
-	return atomic.LoadInt32(&l.keychain[closing]) == int32(w)
+	return atomic.LoadInt32(&l.keychain[closing]) == w
 }
 
 func (l *locker) status(k key) int32 {

connection_reactor.go

@@ -119,13 +119,13 @@ func (c *connection) inputAck(n int) (err error) {
 }
 
 // outputs implements FDOperator.
-func (c *connection) outputs(vs [][]byte) (rs [][]byte, supportZeroCopy bool) {
+func (c *connection) outputs(vs [][]byte) (rs [][]byte, _ bool) {
 	if c.outputBuffer.IsEmpty() {
 		c.rw2r()
-		return rs, c.supportZeroCopy
+		return rs, false
 	}
 	rs = c.outputBuffer.GetBytes(vs)
-	return rs, c.supportZeroCopy
+	return rs, false
 }
 
 // outputAck implements FDOperator.

connection_test.go

@@ -688,6 +688,7 @@ func TestConnectionServerClose(t *testing.T) {
 		WithOnPrepare(func(connection Connection) context.Context {
 			// t.Logf("server.OnPrepare: addr=%s", connection.RemoteAddr())
 			defer wg.Done()
+			//nolint:staticcheck // SA1029 no built-in type string as key
 			return context.WithValue(context.Background(), "prepare", "true")
 		}),
 	)

fd_operator.go

@@ -36,6 +36,7 @@ type FDOperator struct {
 	InputAck func(n int) (err error)
 
 	// Outputs will locked if len(rs) > 0, which need unlocked by OutputAck.
+	// supportZeroCopy is not implemented, and it will be ignored
 	Outputs   func(vs [][]byte) (rs [][]byte, supportZeroCopy bool)
 	OutputAck func(n int) (err error)
 

net_listener_test.go

@@ -80,7 +80,7 @@ func TestListenerDialer(t *testing.T) {
 		conn.SetOnRequest(onRequest)
 
 		MustNil(t, err)
-		n, err := conn.Write([]byte(msg))
+		n, err := conn.Write(msg)
 		MustNil(t, err)
 		Equal(t, n, len(msg))
 		time.Sleep(10 * time.Millisecond)

net_sock.go

@@ -40,7 +40,7 @@ type sockaddr interface {
 }
 
 func internetSocket(ctx context.Context, net string, laddr, raddr sockaddr, sotype, proto int, mode string) (conn *netFD, err error) {
-	if (runtime.GOOS == "aix" || runtime.GOOS == "windows" || runtime.GOOS == "openbsd" || runtime.GOOS == "nacl") && raddr.isWildcard() {
+	if (runtime.GOOS == "aix" || runtime.GOOS == "openbsd" || runtime.GOOS == "nacl") && raddr.isWildcard() {
 		raddr = raddr.toLocal(net)
 	}
 	family, ipv6only := favoriteAddrFamily(net, laddr, raddr)

poll_default_bsd.go

@@ -52,7 +52,7 @@ func openDefaultPoll() (*defaultPoll, error) {
 type defaultPoll struct {
 	fd      int
 	trigger uint32
-	m       sync.Map       // only used in go:race
+	m       sync.Map       //nolint:unused // only used in go:race
 	opcache *operatorCache // operator cache
 	hups    []func(p Poll) error
 }

poll_default_linux.go

@@ -199,10 +199,9 @@ func (p *defaultPoll) handler(events []epollevent) (closed bool) {
 				operator.OnWrite(p)
 			} else if operator.Outputs != nil {
 				// for connection
-				bs, supportZeroCopy := operator.Outputs(p.barriers[i].bs)
+				bs, _ := operator.Outputs(p.barriers[i].bs)
 				if len(bs) > 0 {
-					// TODO: Let the upper layer pass in whether to use ZeroCopy.
-					n, err := iosend(operator.FD, bs, p.barriers[i].ivs, false && supportZeroCopy)
+					n, err := iosend(operator.FD, bs, p.barriers[i].ivs, false)
 					operator.OutputAck(n)
 					if err != nil {
 						p.appendHup(operator)

poll_manager.go

@@ -144,6 +144,7 @@ START:
 	// m.Run() will finish very quickly, so will not many goroutines block on Pick.
 	_ = m.Run()
 
+	//nolint:staticcheck // SA9003: empty branch
 	if !atomic.CompareAndSwapInt32(&m.status, managerInitializing, managerInitialized) {
 		// SetNumLoops called during m.Run() which cause CAS failed
 		// The polls will be adjusted next Pick