3 files changed, 75 insertions, 0 deletions
diff --git a/packages/utils/src/abi_utils.ts b/packages/utils/src/abi_utils.ts
new file mode 100644
index 000000000..c4533d42e
--- /dev/null
+++ b/packages/utils/src/abi_utils.ts
@@ -0,0 +1,71 @@
+import { AbiDefinition, AbiType, ConstructorAbi, ContractAbi, DataItem, MethodAbi } from '@0xproject/types';
+import * as _ from 'lodash';
+
+export const abiUtils = {
+    parseFunctionParam(param: DataItem): string {
+        if (param.type === 'tuple') {
+            // Parse out tuple types into {type_1, type_2, ..., type_N}
+            const tupleComponents = param.components;
+            const paramString = _.map(tupleComponents, component => this.parseFunctionParam(component));
+            const tupleParamString = `{${paramString}}`;
+            return tupleParamString;
+        }
+        return param.type;
+    },
+    getFunctionSignature(methodAbi: MethodAbi): string {
+        const functionName = methodAbi.name;
+        const parameterTypeList = _.map(methodAbi.inputs, (param: DataItem) => this.parseFunctionParam(param));
+        const functionSignature = `${functionName}(${parameterTypeList})`;
+        return functionSignature;
+    },
+    /**
+     * Solidity supports function overloading whereas TypeScript does not.
+     * See: https://solidity.readthedocs.io/en/v0.4.21/contracts.html?highlight=overload#function-overloading
+     * In order to support overloaded functions, we suffix overloaded function names with an index.
+     * This index should be deterministic, regardless of function ordering within the smart contract. To do so,
+     * we assign indexes based on the alphabetical order of function signatures.
+     *
+     * E.g
+     * ['f(uint)', 'f(uint,byte32)']
+     * Should always be renamed to:
+     * ['f1(uint)', 'f2(uint,byte32)']
+     * Regardless of the order in which these these overloaded functions are declared within the contract ABI.
+     */
+    renameOverloadedMethods(inputContractAbi: ContractAbi): ContractAbi {
+        const contractAbi = _.cloneDeep(inputContractAbi);
+        const methodAbis = contractAbi.filter((abi: AbiDefinition) => abi.type === AbiType.Function) as MethodAbi[];
+        // Sort method Abis into alphabetical order, by function signature
+        const methodAbisOrdered = _.sortBy(methodAbis, [
+            (methodAbi: MethodAbi) => {
+                const functionSignature = this.getFunctionSignature(methodAbi);
+                return functionSignature;
+            },
+        ]);
+        // Group method Abis by name (overloaded methods will be grouped together, in alphabetical order)
+        const methodAbisByName: { [key: string]: MethodAbi[] } = {};
+        _.each(methodAbisOrdered, methodAbi => {
+            (methodAbisByName[methodAbi.name] || (methodAbisByName[methodAbi.name] = [])).push(methodAbi);
+        });
+        // Rename overloaded methods to overloadedMethodName1, overloadedMethodName2, ...
+        _.each(methodAbisByName, methodAbisWithSameName => {
+            _.each(methodAbisWithSameName, (methodAbi, i: number) => {
+                if (methodAbisWithSameName.length > 1) {
+                    const overloadedMethodId = i + 1;
+                    const sanitizedMethodName = `${methodAbi.name}${overloadedMethodId}`;
+                    const indexOfExistingAbiWithSanitizedMethodNameIfExists = _.findIndex(
+                        methodAbis,
+                        currentMethodAbi => currentMethodAbi.name === sanitizedMethodName,
+                    );
+                    if (indexOfExistingAbiWithSanitizedMethodNameIfExists >= 0) {
+                        const methodName = methodAbi.name;
+                        throw new Error(
+                            `Failed to rename overloaded method '${methodName}' to '${sanitizedMethodName}'. A method with this name already exists.`,
+                        );
+                    }
+                    methodAbi.name = sanitizedMethodName;
+                }
+            });
+        });
+        return contractAbi;
+    },
+};
diff --git a/packages/utils/src/constants.ts b/packages/utils/src/constants.ts
new file mode 100644
index 000000000..2894d4747
--- /dev/null
+++ b/packages/utils/src/constants.ts
@@ -0,0 +1 @@
+export const NULL_BYTES = '0x';
diff --git a/packages/utils/src/index.ts b/packages/utils/src/index.ts
index debcce746..75c096ee6 100644
--- a/packages/utils/src/index.ts
+++ b/packages/utils/src/index.ts
@@ -5,3 +5,6 @@ export { intervalUtils } from './interval_utils';
 export { BigNumber } from './configured_bignumber';
 export { AbiDecoder } from './abi_decoder';
 export { logUtils } from './log_utils';
+export { abiUtils } from './abi_utils';
+
+export { NULL_BYTES } from './constants';