Add store for MethodDecoding (#3821)

* Add Loader to Transactions

* Add Method Decoding Store (better fetching of methods)

* Load locally stored ABI in MethodDecodingStore

* Fixes UI glitches along the way

* Linting

* Add method decoding from User Contracts

js/src/ui/MethodDecoding/methodDecodingStore.js

@@ -0,0 +1,216 @@
+// Copyright 2015, 2016 Ethcore (UK) Ltd.
+// This file is part of Parity.
+
+// Parity is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+
+// Parity is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License
+// along with Parity.  If not, see <http://www.gnu.org/licenses/>.
+
+import Contracts from '~/contracts';
+import Abi from '~/abi';
+import * as abis from '~/contracts/abi';
+
+const CONTRACT_CREATE = '0x60606040';
+
+let instance = null;
+
+export default class MethodDecodingStore {
+
+  api = null;
+
+  _isContract = {};
+  _methods = {};
+
+  constructor (api, contracts = {}) {
+    this.api = api;
+
+    // Load the signatures from the local ABIs
+    Object.keys(abis).forEach((abiKey) => {
+      this.loadFromAbi(abis[abiKey]);
+    });
+
+    this.addContracts(contracts);
+  }
+
+  addContracts (contracts = {}) {
+    // Load the User defined contracts
+    Object.values(contracts).forEach((contract) => {
+      if (!contract || !contract.meta || !contract.meta.abi) {
+        return;
+      }
+      this.loadFromAbi(contract.meta.abi);
+    });
+  }
+
+  loadFromAbi (_abi) {
+    const abi = new Abi(_abi);
+    abi
+      .functions
+      .map((f) => ({ sign: f.signature, abi: f.abi }))
+      .forEach((mapping) => {
+        const sign = (/^0x/.test(mapping.sign) ? '' : '0x') + mapping.sign;
+        this._methods[sign] = mapping.abi;
+      });
+  }
+
+  static get (api, contracts = {}) {
+    if (!instance) {
+      instance = new MethodDecodingStore(api, contracts);
+    }
+
+    // Set API if not set yet
+    if (!instance.api) {
+      instance.api = api;
+    }
+
+    return instance;
+  }
+
+  static loadContracts (contracts = {}) {
+    if (!instance) {
+      // Just create the instance with null API
+      MethodDecodingStore.get(null, contracts);
+    } else {
+      instance.addContracts(contracts);
+    }
+  }
+
+  /**
+   * Looks up a transaction in the context of the given
+   * address
+   *
+   * @param  {String} address      The address contract
+   * @param  {Object} transaction  The transaction to lookup
+   * @return {Promise}             The result of the lookup. Resolves with:
+   *      {
+   *        contract: Boolean,
+   *        deploy: Boolean,
+   *        inputs: Array,
+   *        name: String,
+   *        params: Array,
+   *        received: Boolean,
+   *        signature: String
+   *      }
+   */
+  lookup (address, transaction) {
+    const result = {};
+
+    if (!transaction) {
+      return Promise.resolve(result);
+    }
+
+    const isReceived = transaction.to === address;
+    const contractAddress = isReceived ? transaction.from : transaction.to;
+    const input = transaction.input || transaction.data;
+
+    result.received = isReceived;
+
+    // No input, should be a ETH transfer
+    if (!input || input === '0x') {
+      return Promise.resolve(result);
+    }
+
+    const { signature, paramdata } = this.api.util.decodeCallData(input);
+    result.signature = signature;
+    result.params = paramdata;
+
+    // Contract deployment
+    if (!signature || signature === CONTRACT_CREATE || transaction.creates) {
+      return Promise.resolve({ ...result, deploy: true });
+    }
+
+    return this
+      .isContract(contractAddress || transaction.creates)
+      .then((isContract) => {
+        result.contract = isContract;
+
+        if (!isContract) {
+          return result;
+        }
+
+        return this
+          .fetchMethodAbi(signature)
+          .then((abi) => {
+            let methodName = null;
+            let methodInputs = null;
+
+            if (abi) {
+              methodName = abi.name;
+              methodInputs = this.api.util
+                .decodeMethodInput(abi, paramdata)
+                .map((value, index) => {
+                  const type = abi.inputs[index].type;
+                  return { type, value };
+                });
+            }
+
+            return {
+              ...result,
+              name: methodName,
+              inputs: methodInputs
+            };
+          });
+      })
+      .catch((error) => {
+        console.warn('lookup', error);
+      });
+  }
+
+  fetchMethodAbi (signature) {
+    if (this._methods[signature] !== undefined) {
+      return Promise.resolve(this._methods[signature]);
+    }
+
+    this._methods[signature] = Contracts.get()
+      .signatureReg
+      .lookup(signature)
+      .then((method) => {
+        let abi = null;
+
+        if (method && method.length) {
+          abi = this.api.util.methodToAbi(method);
+        }
+
+        this._methods[signature] = abi;
+        return this._methods[signature];
+      });
+
+    return Promise.resolve(this._methods[signature]);
+  }
+
+  /**
+   * Checks (and caches) if the given address is a
+   * Contract or not, from its fetched bytecode
+   */
+  isContract (contractAddress) {
+    // If zero address, it isn't a contract
+    if (/^(0x)?0*$/.test(contractAddress)) {
+      return Promise.resolve(false);
+    }
+
+    if (this._isContract[contractAddress]) {
+      return Promise.resolve(this._isContract[contractAddress]);
+    }
+
+    this._isContract[contractAddress] = this.api.eth
+      .getCode(contractAddress)
+      .then((bytecode) => {
+        // Is a contract if the address contains *valid* bytecode
+        const _isContract = bytecode && /^(0x)?([0]*[1-9a-f]+[0]*)+$/.test(bytecode);
+
+        this._isContract[contractAddress] = _isContract;
+        return this._isContract[contractAddress];
+      });
+
+    return Promise.resolve(this._isContract[contractAddress]);
+  }
+
+}