github.com/ethereum/go-ethereum@v1.14.3/accounts/abi/error.go (about) 1 // Copyright 2016 The go-ethereum Authors 2 // This file is part of the go-ethereum library. 3 // 4 // The go-ethereum library is free software: you can redistribute it and/or modify 5 // it under the terms of the GNU Lesser General Public License as published by 6 // the Free Software Foundation, either version 3 of the License, or 7 // (at your option) any later version. 8 // 9 // The go-ethereum library is distributed in the hope that it will be useful, 10 // but WITHOUT ANY WARRANTY; without even the implied warranty of 11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 // GNU Lesser General Public License for more details. 13 // 14 // You should have received a copy of the GNU Lesser General Public License 15 // along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>. 16 17 package abi 18 19 import ( 20 "bytes" 21 "fmt" 22 "strings" 23 24 "github.com/ethereum/go-ethereum/common" 25 "github.com/ethereum/go-ethereum/crypto" 26 ) 27 28 type Error struct { 29 Name string 30 Inputs Arguments 31 str string 32 33 // Sig contains the string signature according to the ABI spec. 34 // e.g. error foo(uint32 a, int b) = "foo(uint32,int256)" 35 // Please note that "int" is substitute for its canonical representation "int256" 36 Sig string 37 38 // ID returns the canonical representation of the error's signature used by the 39 // abi definition to identify event names and types. 40 ID common.Hash 41 } 42 43 func NewError(name string, inputs Arguments) Error { 44 // sanitize inputs to remove inputs without names 45 // and precompute string and sig representation. 46 names := make([]string, len(inputs)) 47 types := make([]string, len(inputs)) 48 for i, input := range inputs { 49 if input.Name == "" { 50 inputs[i] = Argument{ 51 Name: fmt.Sprintf("arg%d", i), 52 Indexed: input.Indexed, 53 Type: input.Type, 54 } 55 } else { 56 inputs[i] = input 57 } 58 // string representation 59 names[i] = fmt.Sprintf("%v %v", input.Type, inputs[i].Name) 60 if input.Indexed { 61 names[i] = fmt.Sprintf("%v indexed %v", input.Type, inputs[i].Name) 62 } 63 // sig representation 64 types[i] = input.Type.String() 65 } 66 67 str := fmt.Sprintf("error %v(%v)", name, strings.Join(names, ", ")) 68 sig := fmt.Sprintf("%v(%v)", name, strings.Join(types, ",")) 69 id := common.BytesToHash(crypto.Keccak256([]byte(sig))) 70 71 return Error{ 72 Name: name, 73 Inputs: inputs, 74 str: str, 75 Sig: sig, 76 ID: id, 77 } 78 } 79 80 func (e Error) String() string { 81 return e.str 82 } 83 84 func (e *Error) Unpack(data []byte) (interface{}, error) { 85 if len(data) < 4 { 86 return "", fmt.Errorf("insufficient data for unpacking: have %d, want at least 4", len(data)) 87 } 88 if !bytes.Equal(data[:4], e.ID[:4]) { 89 return "", fmt.Errorf("invalid identifier, have %#x want %#x", data[:4], e.ID[:4]) 90 } 91 return e.Inputs.Unpack(data[4:]) 92 }