From 25b5e6c98009cf39a73b556a2ac3488d736426fa Mon Sep 17 00:00:00 2001
From: Iuri Matias <iuri.matias@gmail.com>
Date: Thu, 8 Feb 2018 13:12:20 -0500
Subject: [PATCH] move execution EventsDecoder to Remix-Lib

---
 remix-lib/index.js                       |   5 +
 remix-lib/src/execution/eventsDecoder.js | 123 +++++++++++++++++++++++
 2 files changed, 128 insertions(+)
 create mode 100644 remix-lib/src/execution/eventsDecoder.js

diff --git a/remix-lib/index.js b/remix-lib/index.js
index 26ef7b0e74..70b2c4e240 100644
--- a/remix-lib/index.js
+++ b/remix-lib/index.js
@@ -17,6 +17,8 @@ var styleGuideDark = require('./src/ui/styleGuideDark')
 var themeChooser = require('./src/ui/theme-chooser')
 var Storage = require('./src/storage')
 
+var EventsDecoder = require('./src/execution/eventsDecoder')
+
 if (typeof (module) !== 'undefined' && typeof (module.exports) !== 'undefined') {
   module.exports = modules()
 }
@@ -49,6 +51,9 @@ function modules () {
       styleGuide: styleGuide,
       styleGuideDark: styleGuideDark,
       themeChooser: themeChooser
+    },
+    execution: {
+      EventsDecoder: EventsDecoder
     }
   }
 }
diff --git a/remix-lib/src/execution/eventsDecoder.js b/remix-lib/src/execution/eventsDecoder.js
new file mode 100644
index 0000000000..2127f469b4
--- /dev/null
+++ b/remix-lib/src/execution/eventsDecoder.js
@@ -0,0 +1,123 @@
+'use strict'
+var ethJSABI = require('ethereumjs-abi')
+var txHelper = require('../execution/txHelper')
+
+/**
+  * Register to txListener and extract events
+  *
+  */
+class EventsDecoder {
+  constructor (opt = {}) {
+    this._api = opt.api
+  }
+
+/**
+  * use Transaction Receipt to decode logs. assume that the transaction as already been resolved by txListener.
+  * logs are decoded only if the contract if known by remix.
+  *
+  * @param {Object} tx - transaction object
+  * @param {Function} cb - callback
+  */
+  parseLogs (tx, contractName, compiledContracts, cb) {
+    if (tx.isCall) return cb(null, { decoded: [], raw: [] })
+    this._api.resolveReceipt(tx, (error, receipt) => {
+      if (error) return cb(error)
+      this._decodeLogs(tx, receipt, contractName, compiledContracts, cb)
+    })
+  }
+
+  _decodeLogs (tx, receipt, contract, contracts, cb) {
+    if (!contract || !receipt) {
+      return cb('cannot decode logs - contract or receipt not resolved ')
+    }
+    if (!receipt.logs) {
+      return cb(null, { decoded: [], raw: [] })
+    }
+    this._decodeEvents(tx, receipt.logs, contract, contracts, cb)
+  }
+
+  _eventABI (contract) {
+    var eventABI = {}
+    contract.abi.forEach(function (funABI, i) {
+      if (funABI.type !== 'event') {
+        return
+      }
+      var hash = ethJSABI.eventID(funABI.name, funABI.inputs.map(function (item) { return item.type }))
+      eventABI[hash.toString('hex')] = { event: funABI.name, inputs: funABI.inputs }
+    })
+    return eventABI
+  }
+
+  _eventsABI (compiledContracts) {
+    var eventsABI = {}
+    txHelper.visitContracts(compiledContracts, (contract) => {
+      eventsABI[contract.name] = this._eventABI(contract.object)
+    })
+    return eventsABI
+  }
+
+  _event (hash, eventsABI) {
+    for (var k in eventsABI) {
+      if (eventsABI[k][hash]) {
+        return eventsABI[k][hash]
+      }
+    }
+    return null
+  }
+
+  _decodeEvents (tx, logs, contractName, compiledContracts, cb) {
+    var eventsABI = this._eventsABI(compiledContracts)
+    var events = []
+    for (var i in logs) {
+      // [address, topics, mem]
+      var log = logs[i]
+      var topicId = log.topics[0]
+      var abi = this._event(topicId.replace('0x', ''), eventsABI)
+      if (abi) {
+        var event
+        try {
+          var decoded = new Array(abi.inputs.length)
+          event = abi.event
+          var indexed = 1
+          var nonindexed = []
+          // decode indexed param
+          abi.inputs.map(function (item, index) {
+            if (item.indexed) {
+              var encodedData = log.topics[indexed].replace('0x', '')
+              try {
+                decoded[index] = ethJSABI.rawDecode([item.type], new Buffer(encodedData, 'hex'))[0]
+                if (typeof decoded[index] !== 'string') {
+                  decoded[index] = ethJSABI.stringify([item.type], decoded[index])
+                }
+              } catch (e) {
+                decoded[index] = encodedData
+              }
+              indexed++
+            } else {
+              nonindexed.push(item.type)
+            }
+          })
+          // decode non indexed param
+          var nonindexededResult = ethJSABI.rawDecode(nonindexed, new Buffer(log.data.replace('0x', ''), 'hex'))
+          nonindexed = ethJSABI.stringify(nonindexed, nonindexededResult)
+          // ordering
+          var j = 0
+          abi.inputs.map(function (item, index) {
+            if (!item.indexed) {
+              decoded[index] = nonindexed[j]
+              j++
+            }
+          })
+        } catch (e) {
+          decoded = log.data
+        }
+        events.push({ topic: topicId, event: event, args: decoded })
+      } else {
+        events.push({ data: log.data, topics: log.topics })
+      }
+    }
+    cb(null, { decoded: events, raw: logs })
+  }
+}
+
+module.exports = EventsDecoder