opt: close file descriptor after OnClose() for UDP along with code im…

…provement

Updates #621

Follows up #622

eventloop_unix.go

@@ -23,6 +23,7 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"net"
 	"os"
 	"strings"
 	"time"
@@ -226,28 +227,38 @@ loop:
 	return nil
 }
 
-func (el *eventloop) close(c *conn, err error) (rerr error) {
-	if addr := c.localAddr; addr != nil && strings.HasPrefix(c.localAddr.Network(), "udp") {
-		rerr = el.poller.Delete(c.fd)
+func (el *eventloop) close(c *conn, err error) error {
+	if !c.opened || el.connections.getConn(c.fd) == nil {
+		return nil // ignore stale connections
+	}
+
+	action := el.eventHandler.OnClose(c, err)
+
+	var errStr strings.Builder
+
+	if _, ok := c.localAddr.(*net.UDPAddr); ok {
+		if err := el.poller.Delete(c.fd); err != nil {
+			err = fmt.Errorf("failed to delete fd=%d from poller in event-loop(%d): %v",
+				c.fd, el.idx, os.NewSyscallError("delete", err))
+			errStr.WriteString(err.Error())
+			errStr.WriteString(" | ")
+		}
 		if _, ok := el.listeners[c.fd]; !ok {
-			rerr = unix.Close(c.fd)
+			if err := unix.Close(c.fd); err != nil {
+				err = fmt.Errorf("failed to close fd=%d in event-loop(%d): %v",
+					c.fd, el.idx, os.NewSyscallError("close", err))
+				errStr.WriteString(err.Error())
+			}
 			el.connections.delConn(c)
 		}
-		if el.eventHandler.OnClose(c, err) == Shutdown {
-			return errorx.ErrEngineShutdown
-		}
 		c.release()
-		return
-	}
-
-	if !c.opened || el.connections.getConn(c.fd) == nil {
-		return // ignore stale connections
+		if errStr.Len() > 0 {
+			return errors.New(strings.TrimSuffix(errStr.String(), " | "))
+		}
+		return el.handleAction(c, action)
 	}
 
 	el.connections.delConn(c)
-	if el.eventHandler.OnClose(c, err) == Shutdown {
-		rerr = errorx.ErrEngineShutdown
-	}
 
 	// Send residual data in buffer back to the remote before actually closing the connection.
 	for !c.outboundBuffer.IsEmpty() {
@@ -262,8 +273,9 @@ func (el *eventloop) close(c *conn, err error) (rerr error) {
 		}
 	}
 
+	c.release()
+
 	err0, err1 := el.poller.Delete(c.fd), unix.Close(c.fd)
-	var errStr strings.Builder
 	if err0 != nil {
 		err0 = fmt.Errorf("failed to delete fd=%d from poller in event-loop(%d): %v",
 			c.fd, el.idx, os.NewSyscallError("delete", err0))
@@ -276,16 +288,10 @@ func (el *eventloop) close(c *conn, err error) (rerr error) {
 		errStr.WriteString(err1.Error())
 	}
 	if errStr.Len() > 0 {
-		if rerr != nil {
-			el.getLogger().Errorf(strings.TrimSuffix(errStr.String(), " | "))
-		} else {
-			rerr = errors.New(strings.TrimSuffix(errStr.String(), " | "))
-		}
+		return errors.New(strings.TrimSuffix(errStr.String(), " | "))
 	}
 
-	c.release()
-
-	return
+	return el.handleAction(c, action)
 }
 
 func (el *eventloop) wake(c *conn) error {
@@ -333,19 +339,6 @@ func (el *eventloop) ticker(ctx context.Context) {
 	}
 }
 
-func (el *eventloop) handleAction(c *conn, action Action) error {
-	switch action {
-	case None:
-		return nil
-	case Close:
-		return el.close(c, nil)
-	case Shutdown:
-		return errorx.ErrEngineShutdown
-	default:
-		return nil
-	}
-}
-
 func (el *eventloop) readUDP(fd int, _ netpoll.IOEvent, _ netpoll.IOFlags) error {
 	n, sa, err := unix.Recvfrom(fd, el.buffer, 0)
 	if err != nil {
@@ -372,6 +365,19 @@ func (el *eventloop) readUDP(fd int, _ netpoll.IOEvent, _ netpoll.IOFlags) error
 	return nil
 }
 
+func (el *eventloop) handleAction(c *conn, action Action) error {
+	switch action {
+	case None:
+		return nil
+	case Close:
+		return el.close(c, nil)
+	case Shutdown:
+		return errorx.ErrEngineShutdown
+	default:
+		return nil
+	}
+}
+
 /*
 func (el *eventloop) execCmd(itf interface{}) (err error) {
 	cmd := itf.(*asyncCmd)

eventloop_windows.go

@@ -18,8 +18,8 @@ import (
 	"bytes"
 	"context"
 	"errors"
+	"net"
 	"runtime"
-	"strings"
 	"sync/atomic"
 	"time"
 
@@ -188,28 +188,31 @@ func (el *eventloop) wake(c *conn) error {
 }
 
 func (el *eventloop) close(c *conn, err error) error {
-	if addr := c.localAddr; addr != nil && strings.HasPrefix(addr.Network(), "udp") {
-		action := el.eventHandler.OnClose(c, err)
+	if _, ok := el.connections[c]; c.localAddr == nil || !ok {
+		return nil // ignore stale wakes.
+	}
+
+	action := el.eventHandler.OnClose(c, err)
+	err = nil
+
+	if _, ok := c.localAddr.(*net.UDPAddr); ok {
 		if c.rawConn != nil {
-			if err := c.rawConn.Close(); err != nil {
-				el.getLogger().Errorf("failed to close connection(%s), error:%v", c.remoteAddr.String(), err)
-			}
+			err = c.rawConn.Close()
 		}
 		c.release()
+		if err != nil {
+			return err
+		}
 		return el.handleAction(c, action)
 	}
 
-	if _, ok := el.connections[c]; !ok {
-		return nil // ignore stale wakes.
-	}
-
 	delete(el.connections, c)
 	el.incConn(-1)
-	action := el.eventHandler.OnClose(c, err)
-	if err := c.rawConn.Close(); err != nil {
-		el.getLogger().Errorf("failed to close connection(%s), error:%v", c.remoteAddr.String(), err)
-	}
+	err = c.rawConn.Close()
 	c.release()
+	if err != nil {
+		return err
+	}
 
 	return el.handleAction(c, action)
 }