235 lines
7.1 KiB
Go
235 lines
7.1 KiB
Go
package dbus
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import (
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"context"
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"errors"
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"strings"
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)
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// BusObject is the interface of a remote object on which methods can be
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// invoked.
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type BusObject interface {
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Call(method string, flags Flags, args ...interface{}) *Call
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CallWithContext(ctx context.Context, method string, flags Flags, args ...interface{}) *Call
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Go(method string, flags Flags, ch chan *Call, args ...interface{}) *Call
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GoWithContext(ctx context.Context, method string, flags Flags, ch chan *Call, args ...interface{}) *Call
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AddMatchSignal(iface, member string, options ...MatchOption) *Call
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RemoveMatchSignal(iface, member string, options ...MatchOption) *Call
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GetProperty(p string) (Variant, error)
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SetProperty(p string, v interface{}) error
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Destination() string
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Path() ObjectPath
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}
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// Object represents a remote object on which methods can be invoked.
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type Object struct {
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conn *Conn
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dest string
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path ObjectPath
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}
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// Call calls a method with (*Object).Go and waits for its reply.
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func (o *Object) Call(method string, flags Flags, args ...interface{}) *Call {
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return <-o.createCall(context.Background(), method, flags, make(chan *Call, 1), args...).Done
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}
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// CallWithContext acts like Call but takes a context
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func (o *Object) CallWithContext(ctx context.Context, method string, flags Flags, args ...interface{}) *Call {
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return <-o.createCall(ctx, method, flags, make(chan *Call, 1), args...).Done
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}
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// MatchOption specifies option for dbus routing match rule. Options can be constructed with WithMatch* helpers.
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// For full list of available options consult
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// https://dbus.freedesktop.org/doc/dbus-specification.html#message-bus-routing-match-rules
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type MatchOption struct {
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key string
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value string
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}
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// WithMatchOption creates match option with given key and value
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func WithMatchOption(key, value string) MatchOption {
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return MatchOption{key, value}
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}
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// WithMatchObjectPath creates match option that filters events based on given path
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func WithMatchObjectPath(path ObjectPath) MatchOption {
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return MatchOption{"path", string(path)}
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}
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func formatMatchOptions(options []MatchOption) string {
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items := make([]string, 0, len(options))
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for _, option := range options {
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items = append(items, option.key+"='"+option.value+"'")
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}
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return strings.Join(items, ",")
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}
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// AddMatchSignal subscribes BusObject to signals from specified interface,
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// method (member). Additional filter rules can be added via WithMatch* option constructors.
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// Note: To filter events by object path you have to specify this path via an option.
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func (o *Object) AddMatchSignal(iface, member string, options ...MatchOption) *Call {
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base := []MatchOption{
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{"type", "signal"},
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{"interface", iface},
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{"member", member},
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}
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options = append(base, options...)
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return o.conn.BusObject().Call(
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"org.freedesktop.DBus.AddMatch",
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0,
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formatMatchOptions(options),
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)
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}
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// RemoveMatchSignal unsubscribes BusObject from signals from specified interface,
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// method (member). Additional filter rules can be added via WithMatch* option constructors
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func (o *Object) RemoveMatchSignal(iface, member string, options ...MatchOption) *Call {
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base := []MatchOption{
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{"type", "signal"},
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{"interface", iface},
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{"member", member},
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}
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options = append(base, options...)
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return o.conn.BusObject().Call(
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"org.freedesktop.DBus.RemoveMatch",
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0,
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formatMatchOptions(options),
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)
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}
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// Go calls a method with the given arguments asynchronously. It returns a
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// Call structure representing this method call. The passed channel will
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// return the same value once the call is done. If ch is nil, a new channel
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// will be allocated. Otherwise, ch has to be buffered or Go will panic.
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//
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// If the flags include FlagNoReplyExpected, ch is ignored and a Call structure
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// is returned with any error in Err and a closed channel in Done containing
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// the returned Call as it's one entry.
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//
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// If the method parameter contains a dot ('.'), the part before the last dot
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// specifies the interface on which the method is called.
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func (o *Object) Go(method string, flags Flags, ch chan *Call, args ...interface{}) *Call {
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return o.createCall(context.Background(), method, flags, ch, args...)
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}
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// GoWithContext acts like Go but takes a context
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func (o *Object) GoWithContext(ctx context.Context, method string, flags Flags, ch chan *Call, args ...interface{}) *Call {
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return o.createCall(ctx, method, flags, ch, args...)
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}
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func (o *Object) createCall(ctx context.Context, method string, flags Flags, ch chan *Call, args ...interface{}) *Call {
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if ctx == nil {
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panic("nil context")
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}
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iface := ""
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i := strings.LastIndex(method, ".")
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if i != -1 {
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iface = method[:i]
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}
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method = method[i+1:]
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msg := new(Message)
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msg.Type = TypeMethodCall
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msg.serial = o.conn.getSerial()
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msg.Flags = flags & (FlagNoAutoStart | FlagNoReplyExpected)
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msg.Headers = make(map[HeaderField]Variant)
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msg.Headers[FieldPath] = MakeVariant(o.path)
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msg.Headers[FieldDestination] = MakeVariant(o.dest)
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msg.Headers[FieldMember] = MakeVariant(method)
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if iface != "" {
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msg.Headers[FieldInterface] = MakeVariant(iface)
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}
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msg.Body = args
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if len(args) > 0 {
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msg.Headers[FieldSignature] = MakeVariant(SignatureOf(args...))
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}
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if msg.Flags&FlagNoReplyExpected == 0 {
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if ch == nil {
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ch = make(chan *Call, 1)
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} else if cap(ch) == 0 {
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panic("dbus: unbuffered channel passed to (*Object).Go")
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}
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ctx, cancel := context.WithCancel(ctx)
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call := &Call{
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Destination: o.dest,
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Path: o.path,
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Method: method,
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Args: args,
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Done: ch,
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ctxCanceler: cancel,
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ctx: ctx,
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}
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o.conn.calls.track(msg.serial, call)
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o.conn.sendMessageAndIfClosed(msg, func() {
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o.conn.calls.handleSendError(msg, ErrClosed)
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cancel()
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})
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go func() {
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<-ctx.Done()
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o.conn.calls.handleSendError(msg, ctx.Err())
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}()
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return call
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}
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done := make(chan *Call, 1)
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call := &Call{
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Err: nil,
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Done: done,
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}
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defer func() {
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call.Done <- call
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close(done)
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}()
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o.conn.sendMessageAndIfClosed(msg, func() {
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call.Err = ErrClosed
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})
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return call
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}
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// GetProperty calls org.freedesktop.DBus.Properties.Get on the given
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// object. The property name must be given in interface.member notation.
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func (o *Object) GetProperty(p string) (Variant, error) {
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idx := strings.LastIndex(p, ".")
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if idx == -1 || idx+1 == len(p) {
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return Variant{}, errors.New("dbus: invalid property " + p)
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}
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iface := p[:idx]
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prop := p[idx+1:]
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result := Variant{}
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err := o.Call("org.freedesktop.DBus.Properties.Get", 0, iface, prop).Store(&result)
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if err != nil {
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return Variant{}, err
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}
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return result, nil
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}
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// SetProperty calls org.freedesktop.DBus.Properties.Set on the given
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// object. The property name must be given in interface.member notation.
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func (o *Object) SetProperty(p string, v interface{}) error {
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idx := strings.LastIndex(p, ".")
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if idx == -1 || idx+1 == len(p) {
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return errors.New("dbus: invalid property " + p)
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}
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iface := p[:idx]
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prop := p[idx+1:]
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return o.Call("org.freedesktop.DBus.Properties.Set", 0, iface, prop, v).Err
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}
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// Destination returns the destination that calls on (o *Object) are sent to.
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func (o *Object) Destination() string {
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return o.dest
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}
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// Path returns the path that calls on (o *Object") are sent to.
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func (o *Object) Path() ObjectPath {
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return o.path
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}
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