forked from cerc-io/plugeth
5127ec10cb
Refactored the abi package parsing and type handling. Relying mostly on
package reflect as opposed to most of our own type reflection. Our own
type reflection is still used however for cases such as Bytes and
FixedBytes (abi: bytes•).
This also inclused several fixes for slice handling of arbitrary and
fixed size for all supported types.
This also further removes implicit type casting such as assigning,
for example `[2]T{} = []T{1}` will fail, however `[2]T{} == []T{1, 2}`
(notice assigning *slice* to fixed size *array*). Assigning arrays to
slices will always succeed if they are of the same element type.
Incidentally also fixes #2379
119 lines
3.8 KiB
Go
119 lines
3.8 KiB
Go
// Copyright 2015 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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"fmt"
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"reflect"
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"strings"
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"github.com/ethereum/go-ethereum/crypto"
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)
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// Callable method given a `Name` and whether the method is a constant.
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// If the method is `Const` no transaction needs to be created for this
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// particular Method call. It can easily be simulated using a local VM.
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// For example a `Balance()` method only needs to retrieve something
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// from the storage and therefor requires no Tx to be send to the
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// network. A method such as `Transact` does require a Tx and thus will
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// be flagged `true`.
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// Input specifies the required input parameters for this gives method.
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type Method struct {
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Name string
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Const bool
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Inputs []Argument
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Outputs []Argument
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}
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func (m Method) pack(method Method, args ...interface{}) ([]byte, error) {
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// Make sure arguments match up and pack them
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if len(args) != len(method.Inputs) {
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return nil, fmt.Errorf("argument count mismatch: %d for %d", len(args), len(method.Inputs))
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}
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// variable input is the output appended at the end of packed
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// output. This is used for strings and bytes types input.
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var variableInput []byte
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var ret []byte
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for i, a := range args {
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input := method.Inputs[i]
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// pack the input
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packed, err := input.Type.pack(reflect.ValueOf(a))
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if err != nil {
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return nil, fmt.Errorf("`%s` %v", method.Name, err)
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}
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// check for a slice type (string, bytes, slice)
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if input.Type.T == StringTy || input.Type.T == BytesTy || input.Type.IsSlice || input.Type.IsArray {
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// calculate the offset
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offset := len(method.Inputs)*32 + len(variableInput)
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// set the offset
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ret = append(ret, packNum(reflect.ValueOf(offset), UintTy)...)
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// Append the packed output to the variable input. The variable input
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// will be appended at the end of the input.
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variableInput = append(variableInput, packed...)
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} else {
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// append the packed value to the input
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ret = append(ret, packed...)
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}
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}
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// append the variable input at the end of the packed input
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ret = append(ret, variableInput...)
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return ret, nil
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}
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// Sig returns the methods string signature according to the ABI spec.
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//
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// Example
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//
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// function foo(uint32 a, int b) = "foo(uint32,int256)"
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//
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// Please note that "int" is substitute for its canonical representation "int256"
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func (m Method) Sig() string {
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types := make([]string, len(m.Inputs))
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i := 0
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for _, input := range m.Inputs {
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types[i] = input.Type.String()
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i++
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}
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return fmt.Sprintf("%v(%v)", m.Name, strings.Join(types, ","))
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}
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func (m Method) String() string {
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inputs := make([]string, len(m.Inputs))
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for i, input := range m.Inputs {
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inputs[i] = fmt.Sprintf("%v %v", input.Name, input.Type)
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}
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outputs := make([]string, len(m.Outputs))
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for i, output := range m.Outputs {
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if len(output.Name) > 0 {
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outputs[i] = fmt.Sprintf("%v ", output.Name)
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}
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outputs[i] += output.Type.String()
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}
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constant := ""
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if m.Const {
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constant = "constant "
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}
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return fmt.Sprintf("function %v(%v) %sreturns(%v)", m.Name, strings.Join(inputs, ", "), constant, strings.Join(outputs, ", "))
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}
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func (m Method) Id() []byte {
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return crypto.Keccak256([]byte(m.Sig()))[:4]
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}
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