78 lines
2.6 KiB
Go
78 lines
2.6 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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"strings"
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"github.com/ethereum/go-ethereum/crypto"
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)
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// Method represents a callable 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 therefore 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 `false`.
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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 Arguments
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Outputs Arguments
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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 (method Method) Sig() string {
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types := make([]string, len(method.Inputs))
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for i, input := range method.Inputs {
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types[i] = input.Type.String()
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}
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return fmt.Sprintf("%v(%v)", method.Name, strings.Join(types, ","))
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}
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func (method Method) String() string {
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inputs := make([]string, len(method.Inputs))
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for i, input := range method.Inputs {
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inputs[i] = fmt.Sprintf("%v %v", input.Type, input.Name)
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}
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outputs := make([]string, len(method.Outputs))
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for i, output := range method.Outputs {
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outputs[i] = output.Type.String()
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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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}
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constant := ""
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if method.Const {
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constant = "constant "
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}
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return fmt.Sprintf("function %v(%v) %sreturns(%v)", method.Name, strings.Join(inputs, ", "), constant, strings.Join(outputs, ", "))
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}
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func (method Method) Id() []byte {
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return crypto.Keccak256([]byte(method.Sig()))[:4]
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}
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