// Copyright 2016 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 ( "bytes" "errors" "fmt" "strings" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/crypto" ) type Error struct { Name string Inputs Arguments str string // Sig contains the string signature according to the ABI spec. // e.g. error foo(uint32 a, int b) = "foo(uint32,int256)" // Please note that "int" is substitute for its canonical representation "int256" Sig string // ID returns the canonical representation of the error's signature used by the // abi definition to identify event names and types. ID common.Hash } func NewError(name string, inputs Arguments) Error { // sanitize inputs to remove inputs without names // and precompute string and sig representation. names := make([]string, len(inputs)) types := make([]string, len(inputs)) for i, input := range inputs { if input.Name == "" { inputs[i] = Argument{ Name: fmt.Sprintf("arg%d", i), Indexed: input.Indexed, Type: input.Type, } } else { inputs[i] = input } // string representation names[i] = fmt.Sprintf("%v %v", input.Type, inputs[i].Name) if input.Indexed { names[i] = fmt.Sprintf("%v indexed %v", input.Type, inputs[i].Name) } // sig representation types[i] = input.Type.String() } str := fmt.Sprintf("error %v(%v)", name, strings.Join(names, ", ")) sig := fmt.Sprintf("%v(%v)", name, strings.Join(types, ",")) id := common.BytesToHash(crypto.Keccak256([]byte(sig))) return Error{ Name: name, Inputs: inputs, str: str, Sig: sig, ID: id, } } func (e *Error) String() string { return e.str } func (e *Error) Unpack(data []byte) (interface{}, error) { if len(data) < 4 { return "", errors.New("invalid data for unpacking") } if !bytes.Equal(data[:4], e.ID[:4]) { return "", errors.New("invalid data for unpacking") } return e.Inputs.Unpack(data[4:]) }