Add ConnOption WithDefaultSendTimeout

conn.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"strings"
 	"sync"
+	"time"
 )
 
 var (
@@ -30,8 +31,9 @@ var ErrClosed = errors.New("dbus: connection closed by user")
 type Conn struct {
 	transport
 
-	ctx       context.Context
-	cancelCtx context.CancelFunc
+	ctx            context.Context
+	cancelCtx      context.CancelFunc
+	defaultTimeout time.Duration
 
 	closeOnce sync.Once
 	closeErr  error
@@ -258,6 +260,14 @@ func WithContext(ctx context.Context) ConnOption {
 	}
 }
 
+// WithDefaultSendTimeout supplies the connection with a default timeout for outgoing messages.
+func WithDefaultSendTimeout(timeout time.Duration) ConnOption {
+	return func(conn *Conn) error {
+		conn.defaultTimeout = timeout
+		return nil
+	}
+}
+
 // NewConn creates a new private *Conn from an already established connection.
 func NewConn(conn io.ReadWriteCloser, opts ...ConnOption) (*Conn, error) {
 	return newConn(genericTransport{conn}, opts...)
@@ -540,7 +550,16 @@ func (conn *Conn) send(ctx context.Context, msg *Message, ch chan *Call) *Call {
 	}
 
 	var call *Call
-	ctx, canceler := context.WithCancel(ctx)
+	var canceler context.CancelFunc
+	if ctx == context.TODO() {
+		if conn.defaultTimeout > 0 {
+			ctx, canceler = context.WithTimeout(context.Background(), conn.defaultTimeout)
+		} else {
+			ctx, canceler = context.WithCancel(context.Background())
+		}
+	} else {
+		ctx, canceler = context.WithCancel(ctx)
+	}
 	msg.serial = conn.getSerial()
 	if msg.Type == TypeMethodCall && msg.Flags&FlagNoReplyExpected == 0 {
 		call = new(Call)

object.go

@@ -31,7 +31,7 @@ type Object struct {
 
 // Call calls a method with (*Object).Go and waits for its reply.
 func (o *Object) Call(method string, flags Flags, args ...interface{}) *Call {
-	return <-o.createCall(context.Background(), method, flags, make(chan *Call, 1), args...).Done
+	return <-o.createCall(context.TODO(), method, flags, make(chan *Call, 1), args...).Done
 }
 
 // CallWithContext acts like Call but takes a context
@@ -90,7 +90,7 @@ func (o *Object) RemoveMatchSignal(iface, member string, options ...MatchOption)
 // If the method parameter contains a dot ('.'), the part before the last dot
 // specifies the interface on which the method is called.
 func (o *Object) Go(method string, flags Flags, ch chan *Call, args ...interface{}) *Call {
-	return o.createCall(context.Background(), method, flags, ch, args...)
+	return o.createCall(context.TODO(), method, flags, ch, args...)
 }
 
 // GoWithContext acts like Go but takes a context