From bc39cd7b894ddf0f3724d4af3cfc30c2638e0939 Mon Sep 17 00:00:00 2001
From: kumavis <aaron@kumavis.me>
Date: Tue, 22 Nov 2016 14:28:31 -0800
Subject: [PATCH] KeyringController - estimateGas->analyzeGasUsage fix gasLimit
 + detect OOG

---
 app/scripts/keyring-controller.js | 66 ++++++++++++++++++++++++++++---
 package.json                      |  1 +
 2 files changed, 62 insertions(+), 5 deletions(-)

diff --git a/app/scripts/keyring-controller.js b/app/scripts/keyring-controller.js
index bf6280016..5432322ac 100644
--- a/app/scripts/keyring-controller.js
+++ b/app/scripts/keyring-controller.js
@@ -1,4 +1,5 @@
 const async = require('async')
+const bind = require('ap').partial
 const ethUtil = require('ethereumjs-util')
 const ethBinToOps = require('eth-bin-to-ops')
 const EthQuery = require('eth-query')
@@ -362,7 +363,7 @@ module.exports = class KeyringController extends EventEmitter {
     // calculate metadata for tx
     async.parallel([
       analyzeForDelegateCall,
-      estimateGas,
+      analyzeGasUsage,
     ], didComplete)
 
     // perform static analyis on the target contract code
@@ -385,14 +386,69 @@ module.exports = class KeyringController extends EventEmitter {
       }
     }
 
-    function estimateGas (cb) {
-      query.estimateGas(txParams, function (err, result) {
+    function analyzeGasUsage (cb) {
+      query.getBlockByNumber('latest', true, function (err, block) {
         if (err) return cb(err)
-        txData.estimatedGas = self.addGasBuffer(result)
-        cb()
+        async.waterfall([
+          bind(estimateGas, txData, block.gasLimit),
+          bind(checkForGasError, txData),
+          bind(setTxGas, txData, block.gasLimit),
+        ], cb)
       })
     }
 
+    function estimateGas(txData, blockGasLimitHex, cb) {
+      const txParams = txData.txParams
+      // check if gasLimit is already specified
+      txData.gasLimitSpecified = Boolean(txParams.gas)
+      // if not, fallback to block gasLimit
+      if (!txData.gasLimitSpecified) {
+        txParams.gas = blockGasLimitHex
+      }
+      // run tx, see if it will OOG
+      query.estimateGas(txParams, cb)
+    }
+
+    function checkForGasError(txData, estimatedGasHex) {
+      txData.estimatedGas = estimatedGasHex
+      // all gas used - must be an error
+      if (estimatedGasHex === txData.txParams.gas) {
+        txData.simulationFails = true
+      }
+      cb()
+    }
+
+    function setTxGas(txData, blockGasLimitHex) {
+      const txParams = txData.txParams
+      // if OOG, nothing more to do
+      if (txData.simulationFails) {
+        cb()
+        return
+      }
+      // if gasLimit was specified and doesnt OOG,
+      // use original specified amount
+      if (txData.gasLimitSpecified) {
+        txData.estimatedGas = txParams.gas
+        cb()
+        return
+      }
+      // if gasLimit not originally specified,
+      // try adding an additional gas buffer to our estimation for safety
+      const estimatedGasBn = new BN(ethUtil.stripHexPrefix(txData.estimatedGas), 16)
+      const blockGasLimitBn = new BN(ethUtil.stripHexPrefix(blockGasLimitHex), 16)
+      const estimationWithBuffer = self.addGasBuffer(estimatedGasBn)
+      // added gas buffer is too high
+      if (estimationWithBuffer.gt(blockGasLimitBn)) {
+        txParams.gas = txData.estimatedGas
+      // added gas buffer is safe
+      } else {
+        const gasWithBufferHex = ethUtil.intToHex(estimationWithBuffer)
+        txParams.gas = gasWithBufferHex
+      }
+      cb()
+      return
+    }
+
     function didComplete (err) {
       if (err) return cb(err)
       configManager.addTx(txData)
diff --git a/package.json b/package.json
index cbe1a7b55..c6b389a6c 100644
--- a/package.json
+++ b/package.json
@@ -33,6 +33,7 @@
     ]
   },
   "dependencies": {
+    "ap": "^0.2.0",
     "async": "^1.5.2",
     "bip39": "^2.2.0",
     "browserify-derequire": "^0.9.4",