Split EVM data types and factory into separate files

1 files changed, 90 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..e8e717bf1
--- /dev/null
+++ b/packages/utils/src/abi_encoder/evm_data_types/method.ts
@@ -0,0 +1,90 @@
+import { DataItem, MethodAbi } from 'ethereum-types';
+import * as ethUtil from 'ethereumjs-util';
+import * as _ from 'lodash';
+
+import { DecodingRules, EncodingRules, RawCalldata } from '../calldata';
+import * as Constants from '../constants';
+import { DataType, DataTypeFactory, MemberDataType } from '../data_type';
+
+import { StaticBytes } from './static_bytes';
+import { Tuple } from './tuple';
+
+export class Method extends MemberDataType {
+    // TMP
+    public selector: string;
+
+    private readonly _methodSignature: string;
+    private readonly _methodSelector: string;
+    private readonly _returnDataTypes: DataType[];
+    private readonly _returnDataItem: DataItem;
+
+    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();
+        this._returnDataTypes = [];
+        this._returnDataItem = { type: 'tuple', name: abi.name, components: abi.outputs };
+        const dummy = new StaticBytes({ type: 'byte', name: 'DUMMY' }, dataTypeFactory); // @TODO TMP
+        _.each(abi.outputs, (dataItem: DataItem) => {
+            this._returnDataTypes.push(this.getFactory().create(dataItem, dummy));
+        });
+    }
+
+    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 '${this.selector}'.`,
+            );
+        }
+        const hasSelector = true;
+        const value = super.decode(calldata, rules, hasSelector);
+        return value;
+    }
+
+    public encodeReturnValues(value: any, rules?: EncodingRules): string {
+        const returnDataType = new Tuple(this._returnDataItem, this.getFactory());
+        const returndata = returnDataType.encode(value, rules);
+        return returndata;
+    }
+
+    public decodeReturnValues(returndata: string, rules?: DecodingRules): any {
+        const returnValues: any[] = [];
+        const rules_: DecodingRules = rules ? rules : { structsAsObjects: false };
+        const rawReturnData = new RawCalldata(returndata, false);
+        _.each(this._returnDataTypes, (dataType: DataType) => {
+            returnValues.push(dataType.generateValue(rawReturnData, rules_));
+        });
+        return returnValues;
+    }
+
+    public getSignature(): string {
+        return this._methodSignature;
+    }
+
+    public getSelector(): string {
+        return this._methodSelector;
+    }
+
+    private _computeSignature(): string {
+        const memberSignature = this._computeSignatureOfMembers();
+        const methodSignature = `${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;
+    }
+}