From 5e0454e75652160b04bdb31b02b68cf68b177732 Mon Sep 17 00:00:00 2001
From: Robert Varga <rovarga@cisco.com>
Date: Thu, 2 Apr 2015 11:58:48 +0200
Subject: [PATCH] CDS: fix TransactionProxy close()/ready() interaction

TransactionProxy is vulnerable to wrong use of close() after ready().
Fix this up so we detect this condition and make it explicit what
happens when.

Change-Id: Id966b57ce53cdc92bc3e53cb0d38b77303ba1c54
Signed-off-by: Robert Varga <rovarga@cisco.com>
---
 .../cluster/datastore/TransactionProxy.java   | 37 ++++++++++++++++---
 1 file changed, 31 insertions(+), 6 deletions(-)

diff --git a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java
index 504612a05f..a2a7a12044 100644
--- a/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java
+++ b/opendaylight/md-sal/sal-distributed-datastore/src/main/java/org/opendaylight/controller/cluster/datastore/TransactionProxy.java
@@ -84,6 +84,12 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
         }
     }
 
+    private static enum TransactionState {
+        OPEN,
+        READY,
+        CLOSED,
+    }
+
     static final Mapper<Throwable, Throwable> SAME_FAILURE_TRANSFORMER =
                                                               new Mapper<Throwable, Throwable>() {
         @Override
@@ -187,7 +193,7 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
     private final ActorContext actorContext;
     private final String transactionChainId;
     private final SchemaContext schemaContext;
-    private boolean inReadyState;
+    private TransactionState state = TransactionState.OPEN;
 
     private volatile boolean initialized;
     private Semaphore operationLimiter;
@@ -293,7 +299,7 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
     private void checkModificationState() {
         Preconditions.checkState(transactionType != TransactionType.READ_ONLY,
                 "Modification operation on read-only transaction is not allowed");
-        Preconditions.checkState(!inReadyState,
+        Preconditions.checkState(state == TransactionState.OPEN,
                 "Transaction is sealed - further modifications are not allowed");
     }
 
@@ -326,7 +332,6 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
         }
     }
 
-
     @Override
     public void write(final YangInstanceIdentifier path, final NormalizedNode<?, ?> data) {
 
@@ -381,12 +386,22 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
         });
     }
 
+    private boolean seal(final TransactionState newState) {
+        if (state == TransactionState.OPEN) {
+            state = newState;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
     @Override
     public DOMStoreThreePhaseCommitCohort ready() {
+        Preconditions.checkState(transactionType != TransactionType.READ_ONLY,
+                "Read-only transactions cannot be readied");
 
-        checkModificationState();
-
-        inReadyState = true;
+        final boolean success = seal(TransactionState.READY);
+        Preconditions.checkState(success, "Transaction %s is %s, it cannot be readied", getIdentifier(), state);
 
         LOG.debug("Tx {} Readying {} transactions for commit", getIdentifier(),
                     txFutureCallbackMap.size());
@@ -441,6 +456,16 @@ public class TransactionProxy extends AbstractDOMStoreTransaction<TransactionIde
 
     @Override
     public void close() {
+        if (!seal(TransactionState.CLOSED)) {
+            if (state == TransactionState.CLOSED) {
+                // Idempotent no-op as per AutoCloseable recommendation
+                return;
+            }
+
+            throw new IllegalStateException(String.format("Transaction %s is ready, it cannot be closed",
+                getIdentifier()));
+        }
+
         for (TransactionFutureCallback txFutureCallback : txFutureCallbackMap.values()) {
             txFutureCallback.enqueueTransactionOperation(new TransactionOperation() {
                 @Override
-- 
2.36.6