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|
package rlp
import (
"fmt"
"math/big"
"reflect"
"sync"
)
type decoder func(*Stream, reflect.Value) error
type typeinfo struct {
decoder
}
var (
typeCacheMutex sync.RWMutex
typeCache = make(map[reflect.Type]*typeinfo)
)
func cachedTypeInfo(typ reflect.Type) (*typeinfo, error) {
typeCacheMutex.RLock()
info := typeCache[typ]
typeCacheMutex.RUnlock()
if info != nil {
return info, nil
}
// not in the cache, need to generate info for this type.
typeCacheMutex.Lock()
defer typeCacheMutex.Unlock()
return cachedTypeInfo1(typ)
}
func cachedTypeInfo1(typ reflect.Type) (*typeinfo, error) {
info := typeCache[typ]
if info != nil {
// another goroutine got the write lock first
return info, nil
}
// put a dummmy value into the cache before generating.
// if the generator tries to lookup itself, it will get
// the dummy value and won't call itself recursively.
typeCache[typ] = new(typeinfo)
info, err := genTypeInfo(typ)
if err != nil {
// remove the dummy value if the generator fails
delete(typeCache, typ)
return nil, err
}
*typeCache[typ] = *info
return typeCache[typ], err
}
var (
decoderInterface = reflect.TypeOf(new(Decoder)).Elem()
bigInt = reflect.TypeOf(big.Int{})
)
func genTypeInfo(typ reflect.Type) (info *typeinfo, err error) {
info = new(typeinfo)
kind := typ.Kind()
switch {
case typ.Implements(decoderInterface):
info.decoder = decodeDecoder
case kind != reflect.Ptr && reflect.PtrTo(typ).Implements(decoderInterface):
info.decoder = decodeDecoderNoPtr
case typ.AssignableTo(reflect.PtrTo(bigInt)):
info.decoder = decodeBigInt
case typ.AssignableTo(bigInt):
info.decoder = decodeBigIntNoPtr
case isInteger(kind):
info.decoder = makeNumDecoder(typ)
case kind == reflect.String:
info.decoder = decodeString
case kind == reflect.Slice || kind == reflect.Array:
info.decoder, err = makeListDecoder(typ)
case kind == reflect.Struct:
info.decoder, err = makeStructDecoder(typ)
case kind == reflect.Ptr:
info.decoder, err = makePtrDecoder(typ)
case kind == reflect.Interface && typ.NumMethod() == 0:
info.decoder = decodeInterface
default:
err = fmt.Errorf("rlp: type %v is not RLP-serializable", typ)
}
return info, err
}
func isInteger(k reflect.Kind) bool {
return k >= reflect.Int && k <= reflect.Uintptr
}
|
