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