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