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package dbus
import (
"errors"
"fmt"
"reflect"
)
var (
typeObjectPather = reflect.TypeOf((*ObjectPather)(nil)).Elem()
typeVariant = reflect.TypeOf(Variant{})
typeSignature = reflect.TypeOf(Signature(""))
typeBlankInterface = reflect.TypeOf((*interface{})(nil)).Elem()
)
type Signature string
func SignatureOf(t reflect.Type) (Signature, error) {
if t.AssignableTo(typeObjectPather) {
return Signature("o"), nil
}
switch t.Kind() {
case reflect.Uint8:
return Signature("y"), nil
case reflect.Bool:
return Signature("b"), nil
case reflect.Int16:
return Signature("n"), nil
case reflect.Uint16:
return Signature("q"), nil
case reflect.Int32:
return Signature("i"), nil
case reflect.Uint32:
return Signature("u"), nil
case reflect.Int64:
return Signature("x"), nil
case reflect.Uint64:
return Signature("t"), nil
case reflect.Float64:
return Signature("d"), nil
case reflect.String:
if t == typeSignature {
return Signature("g"), nil
}
return Signature("s"), nil
case reflect.Array, reflect.Slice:
valueSig, err := SignatureOf(t.Elem())
if err != nil {
return Signature(""), err
}
return Signature("a") + valueSig, nil
case reflect.Map:
keySig, err := SignatureOf(t.Key())
if err != nil {
return Signature(""), err
}
valueSig, err := SignatureOf(t.Elem())
if err != nil {
return Signature(""), err
}
return Signature("a{") + keySig + valueSig + Signature("}"), nil
case reflect.Struct:
// Special case the variant structure
if t == typeVariant {
return Signature("v"), nil
}
sig := Signature("(")
for i := 0; i != t.NumField(); i++ {
fieldSig, err := SignatureOf(t.Field(i).Type)
if err != nil {
return Signature(""), err
}
sig += fieldSig
}
sig += Signature(")")
return sig, nil
case reflect.Ptr:
// dereference pointers
sig, err := SignatureOf(t.Elem())
return sig, err
}
return Signature(""), errors.New("Can not determine signature for " + t.String())
}
func (sig Signature) NextType(offset int) (next int, err error) {
if offset >= len(sig) {
err = errors.New("No more types codes in signature")
return
}
switch sig[offset] {
case 'y', 'b', 'n', 'q', 'i', 'u', 'x', 't', 'd', 's', 'o', 'g', 'v', 'h':
// A basic type code.
next = offset + 1
case 'a':
// An array: consume the embedded type code
next, err = sig.NextType(offset + 1)
case '{':
// A pair used in maps: consume the two contained types
next, err = sig.NextType(offset + 1)
if err != nil {
return
}
next, err = sig.NextType(next)
if err != nil {
return
}
if next >= len(sig) || sig[next] != '}' {
err = errors.New("Pair does not end with '}'")
return
}
next += 1
case '(':
// A struct: consume types until we
next = offset + 1
for {
if next < len(sig) && sig[next] == ')' {
next += 1
return
}
next, err = sig.NextType(next)
if err != nil {
return
}
}
default:
err = errors.New("Unknown type code " + string(sig[offset]))
}
return
}
// Validate that the signature is a valid string of type codes
func (sig Signature) Validate() (err error) {
offset := 0
for offset < len(sig) {
offset, err = sig.NextType(offset)
if err != nil {
break
}
}
return
}
type ObjectPath string
type ObjectPather interface {
ObjectPath() ObjectPath
}
func (o ObjectPath) ObjectPath() ObjectPath {
return o
}
type Variant struct {
Value interface{}
}
func (v *Variant) GetVariantSignature() (Signature, error) {
return SignatureOf(reflect.TypeOf(v.Value))
}
type Error struct {
Name string
Message string
}
func (e *Error) Error() string {
return fmt.Sprint(e.Name, ": ", e.Message)
}
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