1 files changed, 224 insertions, 0 deletions
diff --git a/packages/utils/src/abi_utils.ts b/packages/utils/src/abi_utils.ts
new file mode 100644
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+++ b/packages/utils/src/abi_utils.ts
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+import { AbiDefinition, AbiType, ContractAbi, DataItem, MethodAbi } from 'ethereum-types';
+import * as ethers from 'ethers';
+import * as _ from 'lodash';
+
+import { BigNumber } from './configured_bignumber';
+
+// Note(albrow): This function is unexported in ethers.js. Copying it here for
+// now.
+// Source: https://github.com/ethers-io/ethers.js/blob/884593ab76004a808bf8097e9753fb5f8dcc3067/contracts/interface.js#L30
+function parseEthersParams(params: DataItem[]): { names: ethers.ParamName[]; types: string[] } {
+    const names: ethers.ParamName[] = [];
+    const types: string[] = [];
+
+    params.forEach((param: DataItem) => {
+        if (param.components != null) {
+            let suffix = '';
+            const arrayBracket = param.type.indexOf('[');
+            if (arrayBracket >= 0) {
+                suffix = param.type.substring(arrayBracket);
+            }
+
+            const result = parseEthersParams(param.components);
+            names.push({ name: param.name || null, names: result.names });
+            types.push('tuple(' + result.types.join(',') + ')' + suffix);
+        } else {
+            names.push(param.name || null);
+            types.push(param.type);
+        }
+    });
+
+    return {
+        names,
+        types,
+    };
+}
+
+// returns true if x is equal to y and false otherwise. Performs some minimal
+// type conversion and data massaging for x and y, depending on type. name and
+// type should typically be derived from parseEthersParams.
+function isAbiDataEqual(name: ethers.ParamName, type: string, x: any, y: any): boolean {
+    if (_.isUndefined(x) && _.isUndefined(y)) {
+        return true;
+    } else if (_.isUndefined(x) && !_.isUndefined(y)) {
+        return false;
+    } else if (!_.isUndefined(x) && _.isUndefined(y)) {
+        return false;
+    }
+    if (_.endsWith(type, '[]')) {
+        // For array types, we iterate through the elements and check each one
+        // individually. Strangely, name does not need to be changed in this
+        // case.
+        if (x.length !== y.length) {
+            return false;
+        }
+        const newType = _.trimEnd(type, '[]');
+        for (let i = 0; i < x.length; i++) {
+            if (!isAbiDataEqual(name, newType, x[i], y[i])) {
+                return false;
+            }
+        }
+        return true;
+    }
+    if (_.startsWith(type, 'tuple(')) {
+        if (_.isString(name)) {
+            throw new Error('Internal error: type was tuple but names was a string');
+        } else if (_.isNull(name)) {
+            throw new Error('Internal error: type was tuple but names was null');
+        }
+        // For tuples, we iterate through the underlying values and check each
+        // one individually.
+        const types = splitTupleTypes(type);
+        if (types.length !== name.names.length) {
+            throw new Error(
+                `Internal error: parameter types/names length mismatch (${types.length} != ${name.names.length})`,
+            );
+        }
+        for (let i = 0; i < types.length; i++) {
+            // For tuples, name is an object with a names property that is an
+            // array. As an example, for orders, name looks like:
+            //
+            //  {
+            //      name: 'orders',
+            //      names: [
+            //          'makerAddress',
+            //          // ...
+            //          'takerAssetData'
+            //      ]
+            //  }
+            //
+            const nestedName = _.isString(name.names[i])
+                ? (name.names[i] as string)
+                : ((name.names[i] as ethers.NestedParamName).name as string);
+            if (!isAbiDataEqual(name.names[i], types[i], x[nestedName], y[nestedName])) {
+                return false;
+            }
+        }
+        return true;
+    } else if (type === 'address' || type === 'bytes') {
+        // HACK(albrow): ethers.js returns the checksummed address even when
+        // initially passed in a non-checksummed address. To account for that,
+        // we convert to lowercase before comparing.
+        return _.isEqual(_.toLower(x), _.toLower(y));
+    } else if (_.startsWith(type, 'uint') || _.startsWith(type, 'int')) {
+        return new BigNumber(x).eq(new BigNumber(y));
+    }
+    return _.isEqual(x, y);
+}
+
+// splitTupleTypes splits a tuple type string (of the form `tuple(X)` where X is
+// any other type or list of types) into its component types. It works with
+// nested tuples, so, e.g., `tuple(tuple(uint256,address),bytes32)` will yield:
+// `['tuple(uint256,address)', 'bytes32']`. It expects exactly one tuple type as
+// an argument (not an array).
+function splitTupleTypes(type: string): string[] {
+    if (_.endsWith(type, '[]')) {
+        throw new Error('Internal error: array types are not supported');
+    } else if (!_.startsWith(type, 'tuple(')) {
+        throw new Error('Internal error: expected tuple type but got non-tuple type: ' + type);
+    }
+    // Trim the outtermost tuple().
+    const trimmedType = type.substring('tuple('.length, type.length - 1);
+    const types: string[] = [];
+    let currToken = '';
+    let parenCount = 0;
+    // Tokenize the type string while keeping track of parentheses.
+    for (const char of trimmedType) {
+        switch (char) {
+            case '(':
+                parenCount += 1;
+                currToken += char;
+                break;
+            case ')':
+                parenCount -= 1;
+                currToken += char;
+                break;
+            case ',':
+                if (parenCount === 0) {
+                    types.push(currToken);
+                    currToken = '';
+                    break;
+                } else {
+                    currToken += char;
+                    break;
+                }
+            default:
+                currToken += char;
+                break;
+        }
+    }
+    types.push(currToken);
+    return types;
+}
+
+export const abiUtils = {
+    parseEthersParams,
+    isAbiDataEqual,
+    splitTupleTypes,
+    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 => abiUtils.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) => abiUtils.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 = abiUtils.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;
+    },
+};