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import { DataItem, MethodAbi } from 'ethereum-types';
import * as ethUtil from 'ethereumjs-util';
import * as _ from 'lodash';
import { DataType, DataTypeFactory, MemberDataType } from '../abstract_data_types';
import { RawCalldata } from '../calldata';
import * as Constants from '../utils/constants';
import { DecodingRules, EncodingRules } from '../utils/rules';
import { Tuple } from './tuple';
export class Method extends MemberDataType {
// TMP
public selector: string;
private readonly _methodSignature: string;
private readonly _methodSelector: string;
private readonly _returnDataType: DataType;
public constructor(abi: MethodAbi, dataTypeFactory: DataTypeFactory) {
super({ type: 'method', name: abi.name, components: abi.inputs }, dataTypeFactory);
this._methodSignature = this._computeSignature();
this.selector = this._methodSelector = this._computeSelector();
const returnDataItem: DataItem = { type: 'tuple', name: abi.name, components: abi.outputs };
this._returnDataType = new Tuple(returnDataItem, this.getFactory());
}
public encode(value: any, rules?: EncodingRules): string {
const calldata = super.encode(value, rules, this.selector);
return calldata;
}
public decode(calldata: string, rules?: DecodingRules): any[] | object {
if (!calldata.startsWith(this.selector)) {
throw new Error(
`Tried to decode calldata, but it was missing the function selector. Expected '${this.selector}'.`,
);
}
const hasSelector = true;
const value = super.decode(calldata, rules, hasSelector);
return value;
}
public encodeReturnValues(value: any, rules?: EncodingRules): string {
const returnData = this._returnDataType.encode(value, rules);
return returnData;
}
public decodeReturnValues(returndata: string, rules?: DecodingRules): any {
const rules_: DecodingRules = rules ? rules : { structsAsObjects: false };
const rawReturnData = new RawCalldata(returndata, false);
const returnValues = this._returnDataType.generateValue(rawReturnData, rules_);
return returnValues;
}
public getSignature(): string {
return this._methodSignature;
}
public getSelector(): string {
return this._methodSelector;
}
private _computeSignature(): string {
const memberSignature = this._computeSignatureOfMembers();
const methodSignature = `${this.getDataItem().name}${memberSignature}`;
return methodSignature;
}
private _computeSelector(): string {
const signature = this._computeSignature();
const selector = ethUtil.bufferToHex(
ethUtil.toBuffer(
ethUtil
.sha3(signature)
.slice(Constants.HEX_SELECTOR_BYTE_OFFSET_IN_CALLDATA, Constants.HEX_SELECTOR_LENGTH_IN_BYTES),
),
);
return selector;
}
}
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