Extend api.util (#4979)

* cleanupValue

* abiUnencode & abiSignature

* Export new functions

js/src/api/util/encode.js

@@ -17,6 +17,10 @@
 import Abi from '~/abi';
 import Func from '~/abi/spec/function';
 
+import { abiDecode } from './decode';
+import { cleanupValue } from './format';
+import { sha3 } from './sha3';
+
 export function encodeMethodCallAbi (methodAbi = {}, values = []) {
   const func = new Func(methodAbi);
   const tokens = Abi.encodeTokens(func.inputParamTypes(), values);
@@ -36,3 +40,30 @@ export function abiEncode (methodName, inputTypes, data) {
 
   return result;
 }
+
+export function abiUnencode (abi, data) {
+  const callsig = data.substr(2, 8);
+  const op = abi.find((field) => {
+    return field.type === 'function' &&
+      abiSignature(field.name, field.inputs.map((input) => input.type)).substr(2, 8) === callsig;
+  });
+
+  if (!op) {
+    console.warn(`Unknown function ID: ${callsig}`);
+    return null;
+  }
+
+  let argsByIndex = abiDecode(op.inputs.map((field) => field.type), '0x' + data.substr(10))
+    .map((value, index) => cleanupValue(value, op.inputs[index].type));
+  const argsByName = op.inputs.reduce((result, field, index) => {
+    result[field.name] = argsByIndex[index];
+
+    return result;
+  }, {});
+
+  return [op.name, argsByName, argsByIndex];
+}
+
+export function abiSignature (name, inputs) {
+  return sha3(`${name}(${inputs.join()})`);
+}

js/src/api/util/encode.spec.js

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-import { abiEncode, encodeMethodCallAbi } from './encode';
+import { abiEncode, abiUnencode, abiSignature, encodeMethodCallAbi } from './encode';
 
 const ABI = {
   type: 'function',
@@ -51,7 +51,11 @@ describe('api/util/encode', () => {
     });
 
     it('encodes variable values', () => {
-      expect(abiEncode('hintUrl', ['bytes32', 'string'], ['0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470', 'http://foo.bar/'])).to.equal(`0x${VARIABLE}`);
+      expect(
+        abiEncode(
+          'hintUrl', ['bytes32', 'string'], ['0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470', 'http://foo.bar/']
+        )
+      ).to.equal(`0x${VARIABLE}`);
     });
 
     it('encodes only the data with null name', () => {
@@ -60,4 +64,27 @@ describe('api/util/encode', () => {
       ).to.equal(`0x${RESULT.substr(8)}`);
     });
   });
+
+  describe('abiUnencode', () => {
+    it('decodes data correctly from abi', () => {
+      expect(
+        abiUnencode([{
+          name: 'test',
+          type: 'function',
+          inputs: [
+            { type: 'uint', name: 'arga' }
+          ]
+        }], '0x1acb6f7700000000000000000000000000000038')
+      ).to.deep.equal(['test', { arga: 56 }, [56]]);
+    });
+  });
+
+  // Same example as in abi/util/signature.spec.js
+  describe('abiSignature', () => {
+    it('encodes baz(uint32,bool) correctly', () => {
+      expect(
+        abiSignature('baz', ['uint32', 'bool'])
+      ).to.equal('0xcdcd77c0992ec5bbfc459984220f8c45084cc24d9b6efed1fae540db8de801d2');
+    });
+  });
 });

js/src/api/util/format.js

@@ -20,6 +20,38 @@ export function bytesToHex (bytes) {
   return '0x' + bytes.map((b) => ('0' + b.toString(16)).slice(-2)).join('');
 }
 
+export function cleanupValue (value, type) {
+  // TODO: make work with arbitrary depth arrays
+  if (value instanceof Array && type.match(/bytes[0-9]+/)) {
+    // figure out if it's an ASCII string hiding in there:
+    let ascii = '';
+
+    for (let index = 0, ended = false; index < value.length && ascii !== null; ++index) {
+      const val = value[index];
+
+      if (val === 0) {
+        ended = true;
+      } else {
+        ascii += String.fromCharCode(val);
+      }
+
+      if ((ended && val !== 0) || (!ended && (val < 32 || val >= 128))) {
+        ascii = null;
+      }
+    }
+
+    value = ascii === null
+      ? bytesToHex(value)
+      : ascii;
+  }
+
+  if (type.substr(0, 4) === 'uint' && +type.substr(4) <= 48) {
+    value = +value;
+  }
+
+  return value;
+}
+
 export function hexToBytes (hex) {
   const raw = toHex(hex).slice(2);
   const bytes = [];

js/src/api/util/format.spec.js

@@ -14,7 +14,7 @@
 // You should have received a copy of the GNU General Public License
 // along with Parity.  If not, see <http://www.gnu.org/licenses/>.
 
-import { bytesToHex, hexToBytes, hexToAscii, bytesToAscii, asciiToHex } from './format';
+import { bytesToHex, cleanupValue, hexToBytes, hexToAscii, bytesToAscii, asciiToHex } from './format';
 
 describe('api/util/format', () => {
   describe('bytesToHex', () => {
@@ -27,6 +27,28 @@ describe('api/util/format', () => {
     });
   });
 
+  describe('cleanupValue', () => {
+    it('returns unknown values as the original', () => {
+      expect(cleanupValue('original', 'unknown')).to.equal('original');
+    });
+
+    it('returns ascii arrays as ascii', () => {
+      expect(cleanupValue([97, 115, 99, 105, 105, 0], 'bytes32')).to.equal('ascii');
+    });
+
+    it('returns non-ascii arrays as hex strings', () => {
+      expect(cleanupValue([97, 200, 0, 0], 'bytes4')).to.equal('0x61c80000');
+    });
+
+    it('returns uint (>48) as the original', () => {
+      expect(cleanupValue('original', 'uint49')).to.equal('original');
+    });
+
+    it('returns uint (<=48) as the number value', () => {
+      expect(cleanupValue('12345', 'uint48')).to.equal(12345);
+    });
+  });
+
   describe('hexToBytes', () => {
     it('correctly converts an empty string', () => {
       expect(hexToBytes('')).to.deep.equal([]);

js/src/api/util/index.js

@@ -16,8 +16,8 @@
 
 import { isAddress as isAddressValid, toChecksumAddress } from '../../abi/util/address';
 import { abiDecode, decodeCallData, decodeMethodInput, methodToAbi } from './decode';
-import { abiEncode, encodeMethodCallAbi } from './encode';
+import { abiEncode, abiUnencode, abiSignature, encodeMethodCallAbi } from './encode';
-import { bytesToHex, hexToAscii, asciiToHex } from './format';
+import { bytesToHex, hexToAscii, asciiToHex, cleanupValue } from './format';
 import { fromWei, toWei } from './wei';
 import { sha3 } from './sha3';
 import { isArray, isFunction, isHex, isInstanceOf, isString } from './types';
@@ -26,6 +26,9 @@ import { createIdentityImg } from './identity';
 export default {
   abiDecode,
   abiEncode,
+  abiUnencode,
+  abiSignature,
+  cleanupValue,
   isAddressValid,
   isArray,
   isFunction,