Add optimizations to encoder and decoder

.golangci.yml

@@ -2,6 +2,25 @@
 
 linters:
   enable:
+    - dupl
+    - exportloopref
+    - gci
+    - goconst
+    - gocritic
+    - gofmt
     - gofumpt
+    - perfsprint
+    - prealloc
     - unconvert
     - unparam
+    - usestdlibvars
+    - wastedassign
+
+linters-settings:
+  gocritic:
+    disabled-checks:
+      - appendAssign
+      - unlambda
+    settings:
+      ifElseChain:
+        minThreshold: 4

auth.go

@@ -35,6 +35,8 @@ const (
 	waitingForReject
 )
 
+const rejectedString = "REJECTED"
+
 // Auth defines the behaviour of an authentication mechanism.
 type Auth interface {
 	// Return the name of the mechanism, the argument to the first AUTH command
@@ -69,7 +71,7 @@ func (conn *Conn) Auth(methods []Auth) error {
 	if err != nil {
 		return err
 	}
-	if len(s) < 2 || !bytes.Equal(s[0], []byte("REJECTED")) {
+	if len(s) < 2 || !bytes.Equal(s[0], []byte(rejectedString)) {
 		return errors.New("dbus: authentication protocol error")
 	}
 	s = s[1:]
@@ -161,7 +163,7 @@ func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (bool, erro
 					return false, err
 				}
 			}
-		case state == waitingForData && string(s[0]) == "REJECTED":
+		case state == waitingForData && string(s[0]) == rejectedString:
 			return false, nil
 		case state == waitingForData && string(s[0]) == "ERROR":
 			err = authWriteLine(conn.transport, []byte("CANCEL"))
@@ -201,7 +203,7 @@ func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (bool, erro
 			if err != nil {
 				return false, nil
 			}
-		case state == waitingForOk && string(s[0]) == "REJECTED":
+		case state == waitingForOk && string(s[0]) == rejectedString:
 			return false, nil
 		case state == waitingForOk && string(s[0]) == "ERROR":
 			err = authWriteLine(conn.transport, []byte("CANCEL"))
@@ -214,7 +216,7 @@ func (conn *Conn) tryAuth(m Auth, state authState, in *bufio.Reader) (bool, erro
 			if err != nil {
 				return false, err
 			}
-		case state == waitingForReject && string(s[0]) == "REJECTED":
+		case state == waitingForReject && string(s[0]) == rejectedString:
 			return false, nil
 		case state == waitingForReject:
 			return false, errors.New("dbus: authentication protocol error")

conn.go

@@ -400,15 +400,17 @@ func (conn *Conn) inWorker() {
 			continue
 		}
 		conn.eavesdroppedLck.Lock()
+		eavesdropped := conn.eavesdropped
+		conn.eavesdroppedLck.Unlock()
+
 		if conn.eavesdropped != nil {
 			select {
-			case conn.eavesdropped <- msg:
+			case eavesdropped <- msg:
 			default:
 			}
-			conn.eavesdroppedLck.Unlock()
+
 			continue
 		}
-		conn.eavesdroppedLck.Unlock()
 		dest, _ := msg.Headers[FieldDestination].value.(string)
 		found := dest == "" ||
 			!conn.names.uniqueNameIsKnown() ||

conn_linux_test.go

@@ -2,7 +2,6 @@ package dbus
 
 import (
 	"bufio"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"syscall"
@@ -46,7 +45,7 @@ func startDaemonInDifferentUserNamespace(t *testing.T) (string, *os.Process) {
 	</policy>   
    </busconfig>
    `
-	cfg, err := ioutil.TempFile("", "")
+	cfg, err := os.CreateTemp("", "")
 	if err != nil {
 		t.Fatal(err)
 	}

conn_other.go

@@ -6,8 +6,6 @@ package dbus
 import (
 	"bytes"
 	"errors"
-	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"os/user"
@@ -54,14 +52,14 @@ func tryDiscoverDbusSessionBusAddress() string {
 		if runUserBusFile := path.Join(runtimeDirectory, "bus"); fileExists(runUserBusFile) {
 			// if /run/user/<uid>/bus exists, that file itself
 			// *is* the unix socket, so return its path
-			return fmt.Sprintf("unix:path=%s", EscapeBusAddressValue(runUserBusFile))
+			return "unix:path=" + EscapeBusAddressValue(runUserBusFile)
 		}
 		if runUserSessionDbusFile := path.Join(runtimeDirectory, "dbus-session"); fileExists(runUserSessionDbusFile) {
 			// if /run/user/<uid>/dbus-session exists, it's a
 			// text file // containing the address of the socket, e.g.:
 			// DBUS_SESSION_BUS_ADDRESS=unix:abstract=/tmp/dbus-E1c73yNqrG
 
-			if f, err := ioutil.ReadFile(runUserSessionDbusFile); err == nil {
+			if f, err := os.ReadFile(runUserSessionDbusFile); err == nil {
 				fileContent := string(f)
 
 				prefix := "DBUS_SESSION_BUS_ADDRESS="
@@ -80,7 +78,7 @@ func getRuntimeDirectory() (string, error) {
 	if currentUser, err := user.Current(); err != nil {
 		return "", err
 	} else {
-		return fmt.Sprintf("/run/user/%s", currentUser.Uid), nil
+		return "/run/user/" + currentUser.Uid, nil
 	}
 }
 

conn_test.go

@@ -5,7 +5,6 @@ import (
 	"encoding/binary"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"log"
 	"sync"
 	"testing"
@@ -170,20 +169,23 @@ func TestCloseBeforeSignal(t *testing.T) {
 	reader, pipewriter := io.Pipe()
 	defer pipewriter.Close()
 	defer reader.Close()
+	wg := sync.WaitGroup{}
 
-	bus, err := NewConn(rwc{Reader: reader, Writer: ioutil.Discard})
+	bus, err := NewConn(rwc{Reader: reader, Writer: io.Discard})
 	if err != nil {
 		t.Fatal(err)
 	}
 	// give ch a buffer so sends won't block
 	ch := make(chan *Signal, 1)
 	bus.Signal(ch)
 
+	wg.Add(1)
 	go func() {
 		_, err := pipewriter.Write([]byte("REJECTED name\r\nOK myuuid\r\n"))
 		if err != nil {
 			t.Errorf("error writing to pipe: %v", err)
 		}
+		wg.Done()
 	}()
 
 	err = bus.Auth([]Auth{fakeAuth{}})
@@ -208,6 +210,7 @@ func TestCloseBeforeSignal(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
+	wg.Wait()
 }
 
 func TestCloseChannelAfterRemoveSignal(t *testing.T) {
@@ -743,7 +746,7 @@ func TestDisconnectCancelsConnectionContext(t *testing.T) {
 	defer pipewriter.Close()
 	defer reader.Close()
 
-	bus, err := NewConn(rwc{Reader: reader, Writer: ioutil.Discard})
+	bus, err := NewConn(rwc{Reader: reader, Writer: io.Discard})
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -778,7 +781,7 @@ func TestCancellingContextClosesConnection(t *testing.T) {
 	defer pipewriter.Close()
 	defer reader.Close()
 
-	bus, err := NewConn(rwc{Reader: reader, Writer: ioutil.Discard}, WithContext(ctx))
+	bus, err := NewConn(rwc{Reader: reader, Writer: io.Discard}, WithContext(ctx))
 	if err != nil {
 		t.Fatal(err)
 	}