func isEmptyValue(v schema.Value) bool {
if !v.IsValid() {
return false
}
switch v.Which() {
case schema.Value_Which_text:
b, _ := v.TextBytes()
return len(b) == 0
case schema.Value_Which_data:
b, _ := v.Data()
return len(b) == 0
case schema.Value_Which_list:
p, _ := v.ListPtr()
return p.List().Len() == 0
default:
return false
}
}
// uintValue returns the unsigned integer value of a schema value or
// zero if the value is invalid (the null pointer). Panics if the value
// is not an unsigned integer.
func uintValue(v schema.Value) uint64 {
if !v.IsValid() {
return 0
}
switch v.Which() {
case schema.Value_Which_uint8:
return uint64(v.Uint8())
case schema.Value_Which_uint16:
return uint64(v.Uint16())
case schema.Value_Which_uint32:
return uint64(v.Uint32())
case schema.Value_Which_uint64:
return v.Uint64()
}
panic("unreachable")
}
// Value formats a value from a schema (like a field default) as Go source.
func (g *generator) Value(rel *node, t schema.Type, v schema.Value) (string, error) {
if !isValueOfType(v, t) {
return "", fmt.Errorf("value type is %v, but found %v value", t.Which(), v.Which())
}
switch t.Which() {
case schema.Type_Which_void:
return "struct{}{}", nil
case schema.Type_Which_interface:
// The only statically representable interface value is null.
return g.imports.Capnp() + ".Client(nil)", nil
case schema.Type_Which_bool:
if v.Bool() {
return "true", nil
} else {
return "false", nil
}
case schema.Type_Which_uint8, schema.Type_Which_uint16, schema.Type_Which_uint32, schema.Type_Which_uint64:
return fmt.Sprintf("uint%d(%d)", intbits(t.Which()), uintValue(v)), nil
case schema.Type_Which_int8, schema.Type_Which_int16, schema.Type_Which_int32, schema.Type_Which_int64:
return fmt.Sprintf("int%d(%d)", intbits(t.Which()), intValue(v)), nil
case schema.Type_Which_float32:
return fmt.Sprintf("%s.Float32frombits(0x%x)", g.imports.Math(), math.Float32bits(v.Float32())), nil
case schema.Type_Which_float64:
return fmt.Sprintf("%s.Float64frombits(0x%x)", g.imports.Math(), math.Float64bits(v.Float64())), nil
case schema.Type_Which_text:
text, _ := v.Text()
return strconv.Quote(text), nil
case schema.Type_Which_data:
buf := make([]byte, 0, 1024)
buf = append(buf, "[]byte{"...)
data, _ := v.Data()
for i, b := range data {
if i > 0 {
buf = append(buf, ',', ' ')
}
buf = strconv.AppendUint(buf, uint64(b), 10)
}
buf = append(buf, '}')
return string(buf), nil
case schema.Type_Which_enum:
en := g.nodes[t.Enum().TypeId()]
if en == nil || !en.IsValid() || en.Which() != schema.Node_Which_enum {
return "", errors.New("expected enum type")
}
enums, _ := en.Enum().Enumerants()
val := int(v.Enum())
if val >= enums.Len() {
rn, err := g.RemoteNodeName(en, rel)
if err != nil {
return "", err
}
return fmt.Sprintf("%s(%d)", rn, val), nil
}
ev := makeEnumval(en, val, enums.At(val))
imp, err := importForNode(en, rel)
if err != nil {
return "", err
}
if imp.path == "" {
return ev.FullName(), nil
}
qname := g.imports.add(imp)
return qname + "." + ev.FullName(), nil
case schema.Type_Which_structType:
data, _ := v.StructValuePtr()
var buf bytes.Buffer
tn, err := g.nodes.mustFind(t.StructType().TypeId())
if err != nil {
return "", err
}
sd, err := g.data.copyData(data)
if err != nil {
return "", err
}
err = templates.ExecuteTemplate(&buf, "structValue", structValueParams{
G: g,
Node: rel,
Typ: tn,
Value: sd,
})
return buf.String(), err
case schema.Type_Which_anyPointer:
data, _ := v.AnyPointerPtr()
var buf bytes.Buffer
sd, err := g.data.copyData(data)
if err != nil {
return "", err
}
err = templates.ExecuteTemplate(&buf, "pointerValue", pointerValueParams{
G: g,
Value: sd,
})
return buf.String(), err
case schema.Type_Which_list:
data, _ := v.ListPtr()
var buf bytes.Buffer
ftyp, err := g.RemoteTypeName(t, rel)
if err != nil {
return "", err
}
sd, err := g.data.copyData(data)
if err != nil {
return "", err
}
err = templates.ExecuteTemplate(&buf, "listValue", listValueParams{
G: g,
Typ: ftyp,
Value: sd,
})
return buf.String(), err
default:
return "", fmt.Errorf("unhandled value type %v", t.Which())
}
}
// intFieldDefaultMask returns the XOR mask used when getting or setting
// signed integer struct fields.
func intFieldDefaultMask(v schema.Value) uint64 {
mask := uint64(1)<<intbits(schema.Type_Which(v.Which())) - 1
return uint64(intValue(v)) & mask
}
func isValueOfType(v schema.Value, t schema.Type) bool {
// Ensure that the value is for the given type. The schema ensures the union ordinals match.
return !v.IsValid() || int(v.Which()) == int(t.Which())
}