IMessageStore extended with method SetAndIncrNextSenderMsgSeqNum, resolves issue #987

QuickFIXn/Session.cs

@@ -1646,9 +1646,12 @@ protected void Persist(Message message, string messageString)
         if (PersistMessages)
         {
             SeqNumType msgSeqNum = message.Header.GetULong(Fields.Tags.MsgSeqNum);
-            _state.Set(msgSeqNum, messageString);
+            _state.SetAndIncrNextSenderMsgSeqNum(msgSeqNum, messageString);
+        }
+        else
+        {
+            _state.IncrNextSenderMsgSeqNum();
         }
-        _state.IncrNextSenderMsgSeqNum();
     }
 
     protected bool IsGoodTime(Message msg)

QuickFIXn/SessionState.cs

@@ -373,6 +373,11 @@ public void IncrNextTargetMsgSeqNum()
         lock (_sync) { MessageStore.IncrNextTargetMsgSeqNum(); }
     }
 
+    public bool SetAndIncrNextSenderMsgSeqNum(SeqNumType msgSeqNum, string msg)
+    {
+        lock (_sync) { return MessageStore.SetAndIncrNextSenderMsgSeqNum(msgSeqNum, msg); }
+    }
+
     public DateTime? CreationTime
     {
         get

QuickFIXn/Store/IMessageStore.cs

@@ -18,7 +18,7 @@ public interface IMessageStore : IDisposable
     void Get(SeqNumType startSeqNum, SeqNumType endSeqNum, List<string> messages);
 
     /// <summary>
-    /// Adds a raw fix message to the store with the give sequence number
+    /// Adds a raw fix message to the store with the given sequence number
     /// </summary>
     /// <param name="msgSeqNum">the sequence number</param>
     /// <param name="msg">the raw FIX message string</param>
@@ -31,6 +31,24 @@ public interface IMessageStore : IDisposable
     void IncrNextSenderMsgSeqNum();
     void IncrNextTargetMsgSeqNum();
 
+    /// <summary>
+    /// The purpose of this method is to combine <see cref="Set(SeqNumType, string)"/>
+    /// and <see cref="IncrNextSenderMsgSeqNum()"/> into one call, for use in situations
+    /// when these operations should be performed together.
+    /// The default implementation simply calls those two functions.
+    /// Certain custom IMessageStore implementations (e.g. DB-backed stores)
+    /// may need to override the default implementation to ensure that these two behaviors
+    /// are combined into a single atomic operation.
+    /// <param name="msgSeqNum">the sequence number</param>
+    /// <param name="msg">the raw FIX message string</param>
+    /// <returns>true if successful, false otherwise</returns>
+    /// </summary>
+    bool SetAndIncrNextSenderMsgSeqNum(SeqNumType msgSeqNum, string msg)
+    {
+        bool result = Set(msgSeqNum, msg);
+        IncrNextSenderMsgSeqNum();
+        return result;
+    }
 
     DateTime? CreationTime { get; }
 
@@ -49,3 +67,4 @@ public interface IMessageStore : IDisposable
     /// </summary>
     void Refresh();
 }
+

RELEASE_NOTES.md

@@ -38,6 +38,7 @@ What's New
 * #949 - new settings RedactFieldsInLogs & RedactionLogText (gbirchmeier)
 * #983 - new MessageFactoryNotFound exception provides better feedback (gbirchmeier)
 * #1014 - deprecate DateTimeConverter.ParseToTimeOnly (gbirchmeier)
+* #987 - new interface method IMessageStore.SetAndIncrNextSenderMsgSeqNum (asmeisne)
 
 
 ### v1.14.0

UnitTests/FileStoreTests.cs

@@ -208,4 +208,30 @@ public void GetTest()
 
         Assert.That(msgs, Is.EqualTo(expected));
     }
+
+    [Test]
+    public void SetAndIncrNextSenderMsgSeqNumTest()
+    {
+        IMessageStore messageStore = _store ?? throw new InvalidProgramException();
+
+        messageStore.SetAndIncrNextSenderMsgSeqNum(1, "dude");
+        messageStore.SetAndIncrNextSenderMsgSeqNum(2, "pude");
+        messageStore.SetAndIncrNextSenderMsgSeqNum(3, "ok");
+        messageStore.SetAndIncrNextSenderMsgSeqNum(4, "ohai");
+
+        var msgs = new List<string>();
+        _store.Get(2, 3, msgs);
+        var expected = new List<string>() { "pude", "ok" };
+
+        Assert.That(msgs, Is.EqualTo(expected));
+        Assert.That(_store.NextSenderMsgSeqNum, Is.EqualTo(5));
+
+        RebuildStore();
+
+        msgs = new List<string>();
+        _store.Get(2, 3, msgs);
+
+        Assert.That(msgs, Is.EqualTo(expected));
+        Assert.That(_store.NextSenderMsgSeqNum, Is.EqualTo(5));
+    }
 }

UnitTests/MemoryStoreTest.cs

@@ -24,4 +24,23 @@ public void GetTest()
         store.Get(5, 6, msgs);
         Assert.That(msgs, Is.Empty);
     }
+
+    [Test]
+    public void SetAndIncrNextSenderMsgSeqNumTest()
+    {
+        IMessageStore store = new MemoryStore();
+        store.SetAndIncrNextSenderMsgSeqNum(1, "dude");
+        store.SetAndIncrNextSenderMsgSeqNum(2, "pude");
+        store.SetAndIncrNextSenderMsgSeqNum(3, "ok");
+        store.SetAndIncrNextSenderMsgSeqNum(4, "ohai");
+        var msgs = new List<string>();
+        store.Get(2, 3, msgs);
+        var expected = new List<string>() { "pude", "ok" };
+        Assert.That(msgs, Is.EqualTo(expected));
+
+        msgs = new List<string>();
+        store.Get(5, 6, msgs);
+        Assert.That(msgs, Is.Empty);
+        Assert.That(store.NextSenderMsgSeqNum, Is.EqualTo(5));
+    }
 }