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package dbus
import (
"bytes"
"fmt"
"reflect"
"sort"
"strconv"
)
// Variant represents the D-Bus variant type.
type Variant struct {
sig Signature
value interface{}
}
// MakeVariant converts the given value to a Variant. It panics if v cannot be
// represented as a D-Bus type.
func MakeVariant(v interface{}) Variant {
return MakeVariantWithSignature(v, SignatureOf(v))
}
// MakeVariantWithSignature converts the given value to a Variant.
func MakeVariantWithSignature(v interface{}, s Signature) Variant {
return Variant{s, v}
}
// ParseVariant parses the given string as a variant as described at
// https://developer.gnome.org/glib/stable/gvariant-text.html. If sig is not
// empty, it is taken to be the expected signature for the variant.
func ParseVariant(s string, sig Signature) (Variant, error) {
tokens := varLex(s)
p := &varParser{tokens: tokens}
n, err := varMakeNode(p)
if err != nil {
return Variant{}, err
}
if sig.str == "" {
sig, err = varInfer(n)
if err != nil {
return Variant{}, err
}
}
v, err := n.Value(sig)
if err != nil {
return Variant{}, err
}
return MakeVariant(v), nil
}
// format returns a formatted version of v and whether this string can be parsed
// unambigously.
func (v Variant) format() (string, bool) {
switch v.sig.str[0] {
case 'b', 'i':
return fmt.Sprint(v.value), true
case 'n', 'q', 'u', 'x', 't', 'd', 'h':
return fmt.Sprint(v.value), false
case 's':
return strconv.Quote(v.value.(string)), true
case 'o':
return strconv.Quote(string(v.value.(ObjectPath))), false
case 'g':
return strconv.Quote(v.value.(Signature).str), false
case 'v':
s, unamb := v.value.(Variant).format()
if !unamb {
return "<@" + v.value.(Variant).sig.str + " " + s + ">", true
}
return "<" + s + ">", true
case 'y':
return fmt.Sprintf("%#x", v.value.(byte)), false
}
rv := reflect.ValueOf(v.value)
switch rv.Kind() {
case reflect.Slice:
if rv.Len() == 0 {
return "[]", false
}
unamb := true
buf := bytes.NewBuffer([]byte("["))
for i := 0; i < rv.Len(); i++ {
// TODO: slooow
s, b := MakeVariant(rv.Index(i).Interface()).format()
unamb = unamb && b
buf.WriteString(s)
if i != rv.Len()-1 {
buf.WriteString(", ")
}
}
buf.WriteByte(']')
return buf.String(), unamb
case reflect.Map:
if rv.Len() == 0 {
return "{}", false
}
unamb := true
var buf bytes.Buffer
kvs := make([]string, rv.Len())
for i, k := range rv.MapKeys() {
s, b := MakeVariant(k.Interface()).format()
unamb = unamb && b
buf.Reset()
buf.WriteString(s)
buf.WriteString(": ")
s, b = MakeVariant(rv.MapIndex(k).Interface()).format()
unamb = unamb && b
buf.WriteString(s)
kvs[i] = buf.String()
}
buf.Reset()
buf.WriteByte('{')
sort.Strings(kvs)
for i, kv := range kvs {
if i > 0 {
buf.WriteString(", ")
}
buf.WriteString(kv)
}
buf.WriteByte('}')
return buf.String(), unamb
}
return `"INVALID"`, true
}
// Signature returns the D-Bus signature of the underlying value of v.
func (v Variant) Signature() Signature {
return v.sig
}
// String returns the string representation of the underlying value of v as
// described at https://developer.gnome.org/glib/stable/gvariant-text.html.
func (v Variant) String() string {
s, unamb := v.format()
if !unamb {
return "@" + v.sig.str + " " + s
}
return s
}
// Value returns the underlying value of v.
func (v Variant) Value() interface{} {
return v.value
}
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