525db7b2c5
adds contextual information to errors returned by unpack
93 lines
2.7 KiB
Go
93 lines
2.7 KiB
Go
// Copyright 2016 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package abi
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import (
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"bytes"
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"fmt"
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"strings"
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"github.com/ethereum/go-ethereum/common"
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"github.com/ethereum/go-ethereum/crypto"
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)
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type Error struct {
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Name string
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Inputs Arguments
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str string
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// Sig contains the string signature according to the ABI spec.
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// e.g. error foo(uint32 a, int b) = "foo(uint32,int256)"
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// Please note that "int" is substitute for its canonical representation "int256"
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Sig string
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// ID returns the canonical representation of the error's signature used by the
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// abi definition to identify event names and types.
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ID common.Hash
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}
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func NewError(name string, inputs Arguments) Error {
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// sanitize inputs to remove inputs without names
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// and precompute string and sig representation.
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names := make([]string, len(inputs))
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types := make([]string, len(inputs))
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for i, input := range inputs {
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if input.Name == "" {
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inputs[i] = Argument{
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Name: fmt.Sprintf("arg%d", i),
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Indexed: input.Indexed,
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Type: input.Type,
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}
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} else {
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inputs[i] = input
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}
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// string representation
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names[i] = fmt.Sprintf("%v %v", input.Type, inputs[i].Name)
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if input.Indexed {
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names[i] = fmt.Sprintf("%v indexed %v", input.Type, inputs[i].Name)
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}
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// sig representation
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types[i] = input.Type.String()
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}
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str := fmt.Sprintf("error %v(%v)", name, strings.Join(names, ", "))
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sig := fmt.Sprintf("%v(%v)", name, strings.Join(types, ","))
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id := common.BytesToHash(crypto.Keccak256([]byte(sig)))
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return Error{
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Name: name,
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Inputs: inputs,
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str: str,
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Sig: sig,
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ID: id,
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}
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}
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func (e Error) String() string {
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return e.str
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}
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func (e *Error) Unpack(data []byte) (interface{}, error) {
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if len(data) < 4 {
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return "", fmt.Errorf("insufficient data for unpacking: have %d, want at least 4", len(data))
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}
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if !bytes.Equal(data[:4], e.ID[:4]) {
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return "", fmt.Errorf("invalid identifier, have %#x want %#x", data[:4], e.ID[:4])
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}
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return e.Inputs.Unpack(data[4:])
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}
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