// Copyright 2015 The go-ethereum Authors // This file is part of the go-ethereum library. // // The go-ethereum library is free software: you can redistribute it and/or modify // it under the terms of the GNU Lesser General Public License as published by // the Free Software Foundation, either version 3 of the License, or // (at your option) any later version. // // The go-ethereum library is distributed in the hope that it will be useful, // but WITHOUT ANY WARRANTY; without even the implied warranty of // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the // GNU Lesser General Public License for more details. // // You should have received a copy of the GNU Lesser General Public License // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. package abi import ( "encoding/json" "fmt" "reflect" "strings" ) // Argument holds the name of the argument and the corresponding type. // Types are used when packing and testing arguments. type Argument struct { Name string Type Type Indexed bool // indexed is only used by events } type Arguments []Argument type ArgumentMarshaling struct { Name string Type string Components []ArgumentMarshaling Indexed bool } // UnmarshalJSON implements json.Unmarshaler interface func (argument *Argument) UnmarshalJSON(data []byte) error { var arg ArgumentMarshaling err := json.Unmarshal(data, &arg) if err != nil { return fmt.Errorf("argument json err: %v", err) } argument.Type, err = NewType(arg.Type, arg.Components) if err != nil { return err } argument.Name = arg.Name argument.Indexed = arg.Indexed return nil } // LengthNonIndexed returns the number of arguments when not counting 'indexed' ones. Only events // can ever have 'indexed' arguments, it should always be false on arguments for method input/output func (arguments Arguments) LengthNonIndexed() int { out := 0 for _, arg := range arguments { if !arg.Indexed { out++ } } return out } // NonIndexed returns the arguments with indexed arguments filtered out func (arguments Arguments) NonIndexed() Arguments { var ret []Argument for _, arg := range arguments { if !arg.Indexed { ret = append(ret, arg) } } return ret } // isTuple returns true for non-atomic constructs, like (uint,uint) or uint[] func (arguments Arguments) isTuple() bool { return len(arguments) > 1 } // Unpack performs the operation hexdata -> Go format func (arguments Arguments) Unpack(v interface{}, data []byte) error { // make sure the passed value is arguments pointer if reflect.Ptr != reflect.ValueOf(v).Kind() { return fmt.Errorf("abi: Unpack(non-pointer %T)", v) } marshalledValues, err := arguments.UnpackValues(data) if err != nil { return err } if arguments.isTuple() { return arguments.unpackTuple(v, marshalledValues) } return arguments.unpackAtomic(v, marshalledValues[0]) } // UnpackIntoMap performs the operation hexdata -> mapping of argument name to argument value func (arguments Arguments) UnpackIntoMap(v map[string]interface{}, data []byte) error { marshalledValues, err := arguments.UnpackValues(data) if err != nil { return err } return arguments.unpackIntoMap(v, marshalledValues) } // unpack sets the unmarshalled value to go format. // Note the dst here must be settable. func unpack(t *Type, dst interface{}, src interface{}) error { var ( dstVal = reflect.ValueOf(dst).Elem() srcVal = reflect.ValueOf(src) ) tuple, typ := false, t for { if typ.T == SliceTy || typ.T == ArrayTy { typ = typ.Elem continue } tuple = typ.T == TupleTy break } if !tuple { return set(dstVal, srcVal) } // Dereferences interface or pointer wrapper dstVal = indirectInterfaceOrPtr(dstVal) switch t.T { case TupleTy: if dstVal.Kind() != reflect.Struct { return fmt.Errorf("abi: invalid dst value for unpack, want struct, got %s", dstVal.Kind()) } fieldmap, err := mapArgNamesToStructFields(t.TupleRawNames, dstVal) if err != nil { return err } for i, elem := range t.TupleElems { fname := fieldmap[t.TupleRawNames[i]] field := dstVal.FieldByName(fname) if !field.IsValid() { return fmt.Errorf("abi: field %s can't found in the given value", t.TupleRawNames[i]) } if err := unpack(elem, field.Addr().Interface(), srcVal.Field(i).Interface()); err != nil { return err } } return nil case SliceTy: if dstVal.Kind() != reflect.Slice { return fmt.Errorf("abi: invalid dst value for unpack, want slice, got %s", dstVal.Kind()) } slice := reflect.MakeSlice(dstVal.Type(), srcVal.Len(), srcVal.Len()) for i := 0; i < slice.Len(); i++ { if err := unpack(t.Elem, slice.Index(i).Addr().Interface(), srcVal.Index(i).Interface()); err != nil { return err } } dstVal.Set(slice) case ArrayTy: if dstVal.Kind() != reflect.Array { return fmt.Errorf("abi: invalid dst value for unpack, want array, got %s", dstVal.Kind()) } array := reflect.New(dstVal.Type()).Elem() for i := 0; i < array.Len(); i++ { if err := unpack(t.Elem, array.Index(i).Addr().Interface(), srcVal.Index(i).Interface()); err != nil { return err } } dstVal.Set(array) } return nil } // unpackIntoMap unpacks marshalledValues into the provided map[string]interface{} func (arguments Arguments) unpackIntoMap(v map[string]interface{}, marshalledValues []interface{}) error { // Make sure map is not nil if v == nil { return fmt.Errorf("abi: cannot unpack into a nil map") } for i, arg := range arguments.NonIndexed() { v[arg.Name] = marshalledValues[i] } return nil } // unpackAtomic unpacks ( hexdata -> go ) a single value func (arguments Arguments) unpackAtomic(v interface{}, marshalledValues interface{}) error { if arguments.LengthNonIndexed() == 0 { return nil } argument := arguments.NonIndexed()[0] elem := reflect.ValueOf(v).Elem() if elem.Kind() == reflect.Struct && argument.Type.T != TupleTy { fieldmap, err := mapArgNamesToStructFields([]string{argument.Name}, elem) if err != nil { return err } field := elem.FieldByName(fieldmap[argument.Name]) if !field.IsValid() { return fmt.Errorf("abi: field %s can't be found in the given value", argument.Name) } return unpack(&argument.Type, field.Addr().Interface(), marshalledValues) } return unpack(&argument.Type, elem.Addr().Interface(), marshalledValues) } // unpackTuple unpacks ( hexdata -> go ) a batch of values. func (arguments Arguments) unpackTuple(v interface{}, marshalledValues []interface{}) error { var ( value = reflect.ValueOf(v).Elem() typ = value.Type() kind = value.Kind() ) if err := requireUnpackKind(value, typ, kind, arguments); err != nil { return err } // If the interface is a struct, get of abi->struct_field mapping var abi2struct map[string]string if kind == reflect.Struct { var ( argNames []string err error ) for _, arg := range arguments.NonIndexed() { argNames = append(argNames, arg.Name) } abi2struct, err = mapArgNamesToStructFields(argNames, value) if err != nil { return err } } for i, arg := range arguments.NonIndexed() { switch kind { case reflect.Struct: field := value.FieldByName(abi2struct[arg.Name]) if !field.IsValid() { return fmt.Errorf("abi: field %s can't be found in the given value", arg.Name) } if err := unpack(&arg.Type, field.Addr().Interface(), marshalledValues[i]); err != nil { return err } case reflect.Slice, reflect.Array: if value.Len() < i { return fmt.Errorf("abi: insufficient number of arguments for unpack, want %d, got %d", len(arguments), value.Len()) } v := value.Index(i) if err := requireAssignable(v, reflect.ValueOf(marshalledValues[i])); err != nil { return err } if err := unpack(&arg.Type, v.Addr().Interface(), marshalledValues[i]); err != nil { return err } default: return fmt.Errorf("abi:[2] cannot unmarshal tuple in to %v", typ) } } return nil } // UnpackValues can be used to unpack ABI-encoded hexdata according to the ABI-specification, // without supplying a struct to unpack into. Instead, this method returns a list containing the // values. An atomic argument will be a list with one element. func (arguments Arguments) UnpackValues(data []byte) ([]interface{}, error) { retval := make([]interface{}, 0, arguments.LengthNonIndexed()) virtualArgs := 0 for index, arg := range arguments.NonIndexed() { marshalledValue, err := toGoType((index+virtualArgs)*32, arg.Type, data) if arg.Type.T == ArrayTy && !isDynamicType(arg.Type) { // If we have a static array, like [3]uint256, these are coded as // just like uint256,uint256,uint256. // This means that we need to add two 'virtual' arguments when // we count the index from now on. // // Array values nested multiple levels deep are also encoded inline: // [2][3]uint256: uint256,uint256,uint256,uint256,uint256,uint256 // // Calculate the full array size to get the correct offset for the next argument. // Decrement it by 1, as the normal index increment is still applied. virtualArgs += getTypeSize(arg.Type)/32 - 1 } else if arg.Type.T == TupleTy && !isDynamicType(arg.Type) { // If we have a static tuple, like (uint256, bool, uint256), these are // coded as just like uint256,bool,uint256 virtualArgs += getTypeSize(arg.Type)/32 - 1 } if err != nil { return nil, err } retval = append(retval, marshalledValue) } return retval, nil } // PackValues performs the operation Go format -> Hexdata // It is the semantic opposite of UnpackValues func (arguments Arguments) PackValues(args []interface{}) ([]byte, error) { return arguments.Pack(args...) } // Pack performs the operation Go format -> Hexdata func (arguments Arguments) Pack(args ...interface{}) ([]byte, error) { // Make sure arguments match up and pack them abiArgs := arguments if len(args) != len(abiArgs) { return nil, fmt.Errorf("argument count mismatch: %d for %d", len(args), len(abiArgs)) } // variable input is the output appended at the end of packed // output. This is used for strings and bytes types input. var variableInput []byte // input offset is the bytes offset for packed output inputOffset := 0 for _, abiArg := range abiArgs { inputOffset += getTypeSize(abiArg.Type) } var ret []byte for i, a := range args { input := abiArgs[i] // pack the input packed, err := input.Type.pack(reflect.ValueOf(a)) if err != nil { return nil, err } // check for dynamic types if isDynamicType(input.Type) { // set the offset ret = append(ret, packNum(reflect.ValueOf(inputOffset))...) // calculate next offset inputOffset += len(packed) // append to variable input variableInput = append(variableInput, packed...) } else { // append the packed value to the input ret = append(ret, packed...) } } // append the variable input at the end of the packed input ret = append(ret, variableInput...) return ret, nil } // ToCamelCase converts an under-score string to a camel-case string func ToCamelCase(input string) string { parts := strings.Split(input, "_") for i, s := range parts { if len(s) > 0 { parts[i] = strings.ToUpper(s[:1]) + s[1:] } } return strings.Join(parts, "") }