1 files changed, 72 insertions, 0 deletions
diff --git a/packages/utils/src/abi_encoder/evm_data_types/method.ts b/packages/utils/src/abi_encoder/evm_data_types/method.ts
new file mode 100644
index 000000000..b1cd1377f
--- /dev/null
+++ b/packages/utils/src/abi_encoder/evm_data_types/method.ts
@@ -0,0 +1,72 @@
+import { DataItem, MethodAbi } from 'ethereum-types';
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import { DataType } from '../abstract_data_types/data_type';
+import { DataTypeFactory } from '../abstract_data_types/interfaces';
+import { AbstractSetDataType } from '../abstract_data_types/types/set';
+import { constants } from '../utils/constants';
+import { DecodingRules, EncodingRules } from '../utils/rules';
+
+import { TupleDataType } from './tuple';
+
+export class MethodDataType extends AbstractSetDataType {
+    private readonly _methodSignature: string;
+    private readonly _methodSelector: string;
+    private readonly _returnDataType: DataType;
+
+    public constructor(abi: MethodAbi, dataTypeFactory: DataTypeFactory) {
+        const methodDataItem = { type: 'method', name: abi.name, components: abi.inputs };
+        super(methodDataItem, dataTypeFactory);
+        this._methodSignature = this._computeSignature();
+        this._methodSelector = this._computeSelector();
+        const returnDataItem: DataItem = { type: 'tuple', name: abi.name, components: abi.outputs };
+        this._returnDataType = new TupleDataType(returnDataItem, this.getFactory());
+    }
+
+    public encode(value: any, rules?: EncodingRules): string {
+        const calldata = super.encode(value, rules, this._methodSelector);
+        return calldata;
+    }
+
+    public decode(calldata: string, rules?: DecodingRules): any[] | object {
+        const value = super.decode(calldata, rules, this._methodSelector);
+        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 returnValues = this._returnDataType.decode(returndata, 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;
+    }
+}