Merge pull request #57 from JSKitty/master

Fixed negative transactions
conradoqg · May 26, 2019 · 1aac1e6 · 1aac1e6
2 parents 9116c57 + bee4d10
commit 1aac1e6
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Showing 2 changed files with 34 additions and 4 deletions.
diff --git a/lib/blockchain/transaction.js b/lib/blockchain/transaction.js
@@ -79,6 +79,17 @@ class Transaction {
             // Check if the sum of input transactions are greater than output transactions, it needs to leave some room for the transaction fee
             let sumOfInputsAmount = R.sum(R.map(R.prop('amount'), this.data.inputs));
             let sumOfOutputsAmount = R.sum(R.map(R.prop('amount'), this.data.outputs));
+
+            let negativeOutputsFound = 0;
+            let i = 0;
+            let outputsLen = this.data.outputs.length;
+
+            // Check for negative outputs
+            for (i = 0; i < outputsLen; i++) {
+                if (this.data.outputs[i].amount < 0) {
+                    negativeOutputsFound++;
+                }
+            }
 
             let isInputsAmountGreaterOrEqualThanOutputsAmount = R.gte(sumOfInputsAmount, sumOfOutputsAmount);
 
@@ -93,6 +104,10 @@ class Transaction {
                 console.error(`Not enough fee: expected '${Config.FEE_PER_TRANSACTION}' got '${(sumOfInputsAmount - sumOfOutputsAmount)}'`);
                 throw new TransactionAssertionError(`Not enough fee: expected '${Config.FEE_PER_TRANSACTION}' got '${(sumOfInputsAmount - sumOfOutputsAmount)}'`, { sumOfInputsAmount, sumOfOutputsAmount, FEE_PER_TRANSACTION: Config.FEE_PER_TRANSACTION });
             }
+            if (negativeOutputsFound > 0) {
+                console.error(`Transaction is either empty or negative, output(s) caught: '${negativeOutputsFound}'`);
+                throw new TransactionAssertionError(`Transaction is either empty or negative, output(s) caught: '${negativeOutputsFound}'`);
+            }
         }
 
         return true;
@@ -106,4 +121,4 @@ class Transaction {
     }
 }
 
-module.exports = Transaction;
+module.exports = Transaction;
diff --git a/lib/miner/index.js b/lib/miner/index.js
@@ -65,6 +65,16 @@ class Miner {
         let rejectedTransactions = [];
         let selectedTransactions = [];
         R.forEach((transaction) => {
+            let negativeOutputsFound = 0;
+            let i = 0;
+            let outputsLen = transaction.data.outputs.length;
+
+            // Check for negative outputs (avoiding negative transactions or 'stealing')
+            for (i = 0; i < outputsLen; i++) {
+                if (transaction.data.outputs[i].amount < 0) {
+                    negativeOutputsFound++;
+                }
+            }
             // Check if any of the inputs is found in the selectedTransactions or in the blockchain
             let transactionInputFoundAnywhere = R.map((input) => {
                 let findInputTransactionInTransactionList = R.find(
@@ -82,9 +92,14 @@ class Miner {
                 return wasItFoundInSelectedTransactions || wasItFoundInBlocks;
             }, transaction.data.inputs);
 
-            // If no input was found, add the transaction to the transaction list to be mined
             if (R.all(R.equals(false), transactionInputFoundAnywhere)) {
-                selectedTransactions.push(transaction);
+                if (transaction.type === 'regular' && negativeOutputsFound === 0) {
+                    selectedTransactions.push(transaction);
+                } else if (transaction.type === 'reward') {
+                    selectedTransactions.push(transaction);
+                } else if (negativeOutputsFound > 0) {
+                    rejectedTransactions.push(transaction);
+                }
             } else {
                 rejectedTransactions.push(transaction);
             }
@@ -164,4 +179,4 @@ class Miner {
     }
 }
 
-module.exports = Miner;
+module.exports = Miner;