tx limit size send peers follow up (#1308)

* Implement max message size rather then cap with fixed number of transactions

Adding transactions to the RLP until the message size exceeds the limit and then send that.

* fix final variables

* Update AbstractRLPOutput.java

add javadoc

* pr discussion

put this factory method on LimitedTransactionsMessages rather than TransactionsMessage since it returns a LimitedTransactionsMessages.

* SpotlessApply

* fix PR discussion

- simplify design
- remove useless code

* Update LimitedTransactionsMessages.java

* fix PR discussion

- simplify logic
- add tests

* Update AbstractRLPOutput.java

* Update ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/messages/LimitedTransactionsMessages.java

Co-Authored-By: abdelhamidbakhta <45264458+abdelhamidbakhta@users.noreply.github.com>

* Update Transaction.java

* fix PR discussion

* fix PR discussion

- add tests

* Update BlockDataGenerator.java

* Update LimitedTransactionsMessagesTest.java

fix PR unit test

* Update LimitedTransactionsMessagesTest.java

* Update LimitedTransactionsMessagesTest.java

Use LinkedHashSet to preserve order.

* Update LimitedTransactionsMessagesTest.java

* follow up PR

Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>

ethereum/eth/src/main/java/tech/pegasys/pantheon/ethereum/eth/messages/LimitedTransactionsMessages.java

@@ -21,7 +21,7 @@ import java.util.Set;
 
 public final class LimitedTransactionsMessages {
 
-  private static final int LIMIT = 1048576;
+  static final int LIMIT = 1048576;
 
   private final TransactionsMessage transactionsMessage;
   private final Set<Transaction> includedTransactions;

ethereum/eth/src/test/java/tech/pegasys/pantheon/ethereum/eth/messages/LimitedTransactionsMessagesTest.java

@@ -14,6 +14,7 @@ package tech.pegasys.pantheon.ethereum.eth.messages;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static tech.pegasys.pantheon.ethereum.eth.messages.LimitedTransactionsMessages.LIMIT;
 
 import tech.pegasys.pantheon.ethereum.core.BlockDataGenerator;
 import tech.pegasys.pantheon.ethereum.core.Transaction;
@@ -27,8 +28,7 @@ import org.junit.Test;
 
 public class LimitedTransactionsMessagesTest {
 
-  private static final int LIMIT = 1048576;
-
+  private static final int TX_PAYLOAD_LIMIT = LIMIT - 180;
   private final BlockDataGenerator generator = new BlockDataGenerator();
   private final Set<Transaction> sampleTxs = generator.transactions(1);
   private final TransactionsMessage sampleTransactionMessages =
@@ -55,11 +55,11 @@ public class LimitedTransactionsMessagesTest {
   }
 
   @Test
-  public void createLimitedWithFirstTransactionExceedingLimit() {
+  public void createLimitedWithTransactionsJustUnderTheLimit() {
     final Set<Transaction> txs = new HashSet<>();
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT - 180])));
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT - 180])));
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT - 180])));
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT])));
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT])));
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT])));
     final LimitedTransactionsMessages firstMessage = LimitedTransactionsMessages.createLimited(txs);
     assertEquals(2, firstMessage.getIncludedTransactions().size());
     txs.removeAll(firstMessage.getIncludedTransactions());
@@ -72,12 +72,13 @@ public class LimitedTransactionsMessagesTest {
   }
 
   @Test
-  public void createLimitedWithFirstTransactionExceedingLimit_2() {
+  public void createLimitedWithTransactionsJustUnderAndJustOverTheLimit() {
     final Set<Transaction> txs = new LinkedHashSet<>();
 
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT - 180])));
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT + 100 - 180])));
-    txs.add(generator.transaction(BytesValue.wrap(new byte[LIMIT - 180])));
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT])));
+    // ensure the next transaction exceed the limit TX_PAYLOAD_LIMIT + 100
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT + 100])));
+    txs.add(generator.transaction(BytesValue.wrap(new byte[TX_PAYLOAD_LIMIT])));
     final LimitedTransactionsMessages firstMessage = LimitedTransactionsMessages.createLimited(txs);
     assertEquals(1, firstMessage.getIncludedTransactions().size());
     txs.removeAll(firstMessage.getIncludedTransactions());