Official Go implementation of the Ethereum protocol
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
go-ethereum/accounts/abi/method.go

169 lines
5.6 KiB

// 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 (
"fmt"
"strings"
"github.com/ethereum/go-ethereum/crypto"
)
// FunctionType represents different types of functions a contract might have.
type FunctionType int
const (
// Constructor represents the constructor of the contract.
// The constructor function is called while deploying a contract.
Constructor FunctionType = iota
// Fallback represents the fallback function.
// This function is executed if no other function matches the given function
// signature and no receive function is specified.
Fallback
// Receive represents the receive function.
// This function is executed on plain Ether transfers.
Receive
// Function represents a normal function.
Function
)
// Method represents a callable given a `Name` and whether the method is a constant.
// If the method is `Const` no transaction needs to be created for this
// particular Method call. It can easily be simulated using a local VM.
// For example a `Balance()` method only needs to retrieve something
// from the storage and therefore requires no Tx to be sent to the
// network. A method such as `Transact` does require a Tx and thus will
// be flagged `false`.
// Input specifies the required input parameters for this gives method.
type Method struct {
// Name is the method name used for internal representation. It's derived from
// the raw name and a suffix will be added in the case of a function overload.
//
// e.g.
// These are two functions that have the same name:
// * foo(int,int)
// * foo(uint,uint)
// The method name of the first one will be resolved as foo while the second one
// will be resolved as foo0.
Name string
RawName string // RawName is the raw method name parsed from ABI
// Type indicates whether the method is a
// special fallback introduced in solidity v0.6.0
Type FunctionType
// StateMutability indicates the mutability state of method,
// the default value is nonpayable. It can be empty if the abi
// is generated by legacy compiler.
StateMutability string
// Legacy indicators generated by compiler before v0.6.0
Constant bool
Payable bool
Inputs Arguments
Outputs Arguments
str string
// Sig returns the methods string signature according to the ABI spec.
// e.g. function 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 method's signature used by the
// abi definition to identify method names and types.
ID []byte
}
// NewMethod creates a new Method.
// A method should always be created using NewMethod.
// It also precomputes the sig representation and the string representation
// of the method.
func NewMethod(name string, rawName string, funType FunctionType, mutability string, isConst, isPayable bool, inputs Arguments, outputs Arguments) Method {
var (
types = make([]string, len(inputs))
inputNames = make([]string, len(inputs))
outputNames = make([]string, len(outputs))
)
for i, input := range inputs {
inputNames[i] = fmt.Sprintf("%v %v", input.Type, input.Name)
types[i] = input.Type.String()
}
for i, output := range outputs {
outputNames[i] = output.Type.String()
if len(output.Name) > 0 {
outputNames[i] += fmt.Sprintf(" %v", output.Name)
}
}
// calculate the signature and method id. Note only function
// has meaningful signature and id.
var (
sig string
id []byte
)
if funType == Function {
sig = fmt.Sprintf("%v(%v)", rawName, strings.Join(types, ","))
id = crypto.Keccak256([]byte(sig))[:4]
}
// Extract meaningful state mutability of solidity method.
// If it's default value, never print it.
state := mutability
if state == "nonpayable" {
state = ""
}
if state != "" {
state = state + " "
}
identity := fmt.Sprintf("function %v", rawName)
switch funType {
case Fallback:
identity = "fallback"
case Receive:
identity = "receive"
case Constructor:
identity = "constructor"
}
str := fmt.Sprintf("%v(%v) %sreturns(%v)", identity, strings.Join(inputNames, ", "), state, strings.Join(outputNames, ", "))
return Method{
Name: name,
RawName: rawName,
Type: funType,
StateMutability: mutability,
Constant: isConst,
Payable: isPayable,
Inputs: inputs,
Outputs: outputs,
str: str,
Sig: sig,
ID: id,
}
}
func (method Method) String() string {
return method.str
}
// IsConstant returns the indicator whether the method is read-only.
func (method Method) IsConstant() bool {
return method.StateMutability == "view" || method.StateMutability == "pure" || method.Constant
}
// IsPayable returns the indicator whether the method can process
// plain ether transfers.
func (method Method) IsPayable() bool {
return method.StateMutability == "payable" || method.Payable
}