ipld-eth-server/pkg/omni/parser/parser.go

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// VulcanizeDB
// Copyright © 2018 Vulcanize
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
// This program 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 Affero General Public License for more details.
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package parser
import (
"github.com/ethereum/go-ethereum/accounts/abi"
"github.com/vulcanize/vulcanizedb/pkg/geth"
"github.com/vulcanize/vulcanizedb/pkg/omni/types"
)
// Parser is used to fetch and parse contract ABIs
// It is dependent on etherscan's api
type Parser interface {
Parse(contractAddr string) error
Abi() string
ParsedAbi() abi.ABI
GetMethods(wanted []string) map[string]*types.Method
GetAddrMethods(wanted []string) map[string]*types.Method
GetEvents(wanted []string) map[string]*types.Event
}
type parser struct {
client *geth.EtherScanAPI
abi string
parsedAbi abi.ABI
}
func NewParser(network string) *parser {
url := geth.GenURL(network)
return &parser{
client: geth.NewEtherScanClient(url),
}
}
func (p *parser) Abi() string {
return p.abi
}
func (p *parser) ParsedAbi() abi.ABI {
return p.parsedAbi
}
// Retrieves and parses the abi string
// for the given contract address
func (p *parser) Parse(contractAddr string) error {
abiStr, err := p.client.GetAbi(contractAddr)
if err != nil {
return err
}
p.abi = abiStr
p.parsedAbi, err = geth.ParseAbi(abiStr)
return err
}
// Returns wanted methods, if they meet the criteria, as map of types.Methods
// Empty wanted array => all methods that fit are returned
// Nil wanted array => no events are returned
func (p *parser) GetAddrMethods(wanted []string) map[string]*types.Method {
addrMethods := map[string]*types.Method{}
if wanted == nil {
return addrMethods
}
for _, m := range p.parsedAbi.Methods {
// Only return methods that have less than 3 inputs, 1 output, and wanted
if len(m.Inputs) < 3 && len(m.Outputs) == 1 && (len(wanted) == 0 || stringInSlice(wanted, m.Name)) {
addrsOnly := true
for _, input := range m.Inputs {
if input.Type.T != abi.AddressTy {
addrsOnly = false
}
}
// Only return methods if inputs are all of type address and output is of the accepted types
if addrsOnly && wantType(m.Outputs[0]) {
method := types.NewMethod(m)
addrMethods[method.Name] = method
}
}
}
return addrMethods
}
// Returns wanted methods as map of types.Methods
// Empty wanted array => all events are returned
// Nil wanted array => no events are returned
func (p *parser) GetMethods(wanted []string) map[string]*types.Method {
methods := map[string]*types.Method{}
if wanted == nil {
return methods
}
length := len(wanted)
for _, m := range p.parsedAbi.Methods {
if length == 0 || stringInSlice(wanted, m.Name) {
methods[m.Name] = types.NewMethod(m)
}
}
return methods
}
// Returns wanted events as map of types.Events
// Empty wanted array => all events are returned
// Nil wanted array => no events are returned
func (p *parser) GetEvents(wanted []string) map[string]*types.Event {
events := map[string]*types.Event{}
if wanted == nil {
return events
}
length := len(wanted)
for _, e := range p.parsedAbi.Events {
if length == 0 || stringInSlice(wanted, e.Name) {
events[e.Name] = types.NewEvent(e)
}
}
return events
}
func wantType(arg abi.Argument) bool {
wanted := []byte{abi.UintTy, abi.IntTy, abi.BoolTy, abi.StringTy, abi.AddressTy, abi.HashTy}
for _, ty := range wanted {
if arg.Type.T == ty {
return true
}
}
return false
}
func stringInSlice(list []string, s string) bool {
for _, b := range list {
if b == s {
return true
}
}
return false
}