status-go/vendor/github.com/godbus/dbus/v5/default_handler.go

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2022-04-01 16:16:46 +00:00
package dbus
import (
"bytes"
"reflect"
"strings"
"sync"
)
func newIntrospectIntf(h *defaultHandler) *exportedIntf {
methods := make(map[string]Method)
methods["Introspect"] = exportedMethod{
reflect.ValueOf(func(msg Message) (string, *Error) {
path := msg.Headers[FieldPath].value.(ObjectPath)
return h.introspectPath(path), nil
}),
}
return newExportedIntf(methods, true)
}
//NewDefaultHandler returns an instance of the default
//call handler. This is useful if you want to implement only
//one of the two handlers but not both.
//
// Deprecated: this is the default value, don't use it, it will be unexported.
func NewDefaultHandler() *defaultHandler {
h := &defaultHandler{
objects: make(map[ObjectPath]*exportedObj),
defaultIntf: make(map[string]*exportedIntf),
}
h.defaultIntf["org.freedesktop.DBus.Introspectable"] = newIntrospectIntf(h)
return h
}
type defaultHandler struct {
sync.RWMutex
objects map[ObjectPath]*exportedObj
defaultIntf map[string]*exportedIntf
}
func (h *defaultHandler) PathExists(path ObjectPath) bool {
_, ok := h.objects[path]
return ok
}
func (h *defaultHandler) introspectPath(path ObjectPath) string {
subpath := make(map[string]struct{})
var xml bytes.Buffer
xml.WriteString("<node>")
for obj := range h.objects {
p := string(path)
if p != "/" {
p += "/"
}
if strings.HasPrefix(string(obj), p) {
node_name := strings.Split(string(obj[len(p):]), "/")[0]
subpath[node_name] = struct{}{}
}
}
for s := range subpath {
xml.WriteString("\n\t<node name=\"" + s + "\"/>")
}
xml.WriteString("\n</node>")
return xml.String()
}
func (h *defaultHandler) LookupObject(path ObjectPath) (ServerObject, bool) {
h.RLock()
defer h.RUnlock()
object, ok := h.objects[path]
if ok {
return object, ok
}
// If an object wasn't found for this exact path,
// look for a matching subtree registration
subtreeObject := newExportedObject()
path = path[:strings.LastIndex(string(path), "/")]
for len(path) > 0 {
object, ok = h.objects[path]
if ok {
for name, iface := range object.interfaces {
// Only include this handler if it registered for the subtree
if iface.isFallbackInterface() {
subtreeObject.interfaces[name] = iface
}
}
break
}
path = path[:strings.LastIndex(string(path), "/")]
}
for name, intf := range h.defaultIntf {
if _, exists := subtreeObject.interfaces[name]; exists {
continue
}
subtreeObject.interfaces[name] = intf
}
return subtreeObject, true
}
func (h *defaultHandler) AddObject(path ObjectPath, object *exportedObj) {
h.Lock()
h.objects[path] = object
h.Unlock()
}
func (h *defaultHandler) DeleteObject(path ObjectPath) {
h.Lock()
delete(h.objects, path)
h.Unlock()
}
type exportedMethod struct {
reflect.Value
}
func (m exportedMethod) Call(args ...interface{}) ([]interface{}, error) {
t := m.Type()
params := make([]reflect.Value, len(args))
for i := 0; i < len(args); i++ {
params[i] = reflect.ValueOf(args[i]).Elem()
}
ret := m.Value.Call(params)
err := ret[t.NumOut()-1].Interface().(*Error)
ret = ret[:t.NumOut()-1]
out := make([]interface{}, len(ret))
for i, val := range ret {
out[i] = val.Interface()
}
if err == nil {
//concrete type to interface nil is a special case
return out, nil
}
return out, err
}
func (m exportedMethod) NumArguments() int {
return m.Value.Type().NumIn()
}
func (m exportedMethod) ArgumentValue(i int) interface{} {
return reflect.Zero(m.Type().In(i)).Interface()
}
func (m exportedMethod) NumReturns() int {
return m.Value.Type().NumOut()
}
func (m exportedMethod) ReturnValue(i int) interface{} {
return reflect.Zero(m.Type().Out(i)).Interface()
}
func newExportedObject() *exportedObj {
return &exportedObj{
interfaces: make(map[string]*exportedIntf),
}
}
type exportedObj struct {
mu sync.RWMutex
interfaces map[string]*exportedIntf
}
func (obj *exportedObj) LookupInterface(name string) (Interface, bool) {
if name == "" {
return obj, true
}
obj.mu.RLock()
defer obj.mu.RUnlock()
intf, exists := obj.interfaces[name]
return intf, exists
}
func (obj *exportedObj) AddInterface(name string, iface *exportedIntf) {
obj.mu.Lock()
defer obj.mu.Unlock()
obj.interfaces[name] = iface
}
func (obj *exportedObj) DeleteInterface(name string) {
obj.mu.Lock()
defer obj.mu.Unlock()
delete(obj.interfaces, name)
}
func (obj *exportedObj) LookupMethod(name string) (Method, bool) {
obj.mu.RLock()
defer obj.mu.RUnlock()
for _, intf := range obj.interfaces {
method, exists := intf.LookupMethod(name)
if exists {
return method, exists
}
}
return nil, false
}
func (obj *exportedObj) isFallbackInterface() bool {
return false
}
func newExportedIntf(methods map[string]Method, includeSubtree bool) *exportedIntf {
return &exportedIntf{
methods: methods,
includeSubtree: includeSubtree,
}
}
type exportedIntf struct {
methods map[string]Method
// Whether or not this export is for the entire subtree
includeSubtree bool
}
func (obj *exportedIntf) LookupMethod(name string) (Method, bool) {
out, exists := obj.methods[name]
return out, exists
}
func (obj *exportedIntf) isFallbackInterface() bool {
return obj.includeSubtree
}
//NewDefaultSignalHandler returns an instance of the default
//signal handler. This is useful if you want to implement only
//one of the two handlers but not both.
//
// Deprecated: this is the default value, don't use it, it will be unexported.
func NewDefaultSignalHandler() *defaultSignalHandler {
return &defaultSignalHandler{}
}
type defaultSignalHandler struct {
mu sync.RWMutex
closed bool
signals []*signalChannelData
}
func (sh *defaultSignalHandler) DeliverSignal(intf, name string, signal *Signal) {
sh.mu.RLock()
defer sh.mu.RUnlock()
if sh.closed {
return
}
for _, scd := range sh.signals {
scd.deliver(signal)
}
}
func (sh *defaultSignalHandler) Terminate() {
sh.mu.Lock()
defer sh.mu.Unlock()
if sh.closed {
return
}
for _, scd := range sh.signals {
scd.close()
close(scd.ch)
}
sh.closed = true
sh.signals = nil
}
func (sh *defaultSignalHandler) AddSignal(ch chan<- *Signal) {
sh.mu.Lock()
defer sh.mu.Unlock()
if sh.closed {
return
}
sh.signals = append(sh.signals, &signalChannelData{
ch: ch,
done: make(chan struct{}),
})
}
func (sh *defaultSignalHandler) RemoveSignal(ch chan<- *Signal) {
sh.mu.Lock()
defer sh.mu.Unlock()
if sh.closed {
return
}
for i := len(sh.signals) - 1; i >= 0; i-- {
if ch == sh.signals[i].ch {
sh.signals[i].close()
copy(sh.signals[i:], sh.signals[i+1:])
sh.signals[len(sh.signals)-1] = nil
sh.signals = sh.signals[:len(sh.signals)-1]
}
}
}
type signalChannelData struct {
wg sync.WaitGroup
ch chan<- *Signal
done chan struct{}
}
func (scd *signalChannelData) deliver(signal *Signal) {
select {
case scd.ch <- signal:
case <-scd.done:
return
default:
scd.wg.Add(1)
go scd.deferredDeliver(signal)
}
}
func (scd *signalChannelData) deferredDeliver(signal *Signal) {
select {
case scd.ch <- signal:
case <-scd.done:
}
scd.wg.Done()
}
func (scd *signalChannelData) close() {
close(scd.done)
scd.wg.Wait() // wait until all spawned goroutines return
}