used concurrentdictionary since PublishedMessages and ReceivedMessages are public and accessed from various places (#1104)

if one thread enumerates through dictionary and the other tries to update it, we get a NullReferenceException

Co-authored-by: Rafal Kozlowski <rafal.kozlowski@external.iherb.com>

src/DotNetCore.CAP.InMemoryStorage/IDataStorage.InMemory.cs

@@ -2,6 +2,7 @@
 // Licensed under the MIT License. See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading;
@@ -26,9 +27,9 @@ namespace DotNetCore.CAP.InMemoryStorage
             _serializer = serializer;
         }
 
-        public static Dictionary<string, MemoryMessage> PublishedMessages { get; } = new();
+        public static ConcurrentDictionary<string, MemoryMessage> PublishedMessages { get; } = new();
 
-        public static Dictionary<string, MemoryMessage> ReceivedMessages { get; } = new();
+        public static ConcurrentDictionary<string, MemoryMessage> ReceivedMessages { get; } = new();
 
         public Task ChangePublishStateAsync(MediumMessage message, StatusName state)
         {
@@ -58,19 +59,16 @@ namespace DotNetCore.CAP.InMemoryStorage
                 Retries = 0
             };
 
-            lock (PublishedMessages)
+            PublishedMessages[message.DbId] = new MemoryMessage
             {
-                PublishedMessages[message.DbId] = new MemoryMessage
-                {
-                    DbId = message.DbId,
-                    Name = name,
-                    Content = message.Content,
-                    Retries = message.Retries,
-                    Added = message.Added,
-                    ExpiresAt = message.ExpiresAt,
-                    StatusName = StatusName.Scheduled
-                };
-            }
+                DbId = message.DbId,
+                Name = name,
+                Content = message.Content,
+                Retries = message.Retries,
+                Added = message.Added,
+                ExpiresAt = message.ExpiresAt,
+                StatusName = StatusName.Scheduled
+            };
 
             return message;
         }
@@ -79,21 +77,18 @@ namespace DotNetCore.CAP.InMemoryStorage
         {
             var id = SnowflakeId.Default().NextId().ToString();
 
-            lock (ReceivedMessages)
+            ReceivedMessages[id] = new MemoryMessage
             {
-                ReceivedMessages[id] = new MemoryMessage
-                {
-                    DbId = id,
-                    Group = group,
-                    Origin = null!,
-                    Name = name,
-                    Content = content,
-                    Retries = _capOptions.Value.FailedRetryCount,
-                    Added = DateTime.Now,
-                    ExpiresAt = DateTime.Now.AddDays(15),
-                    StatusName = StatusName.Failed
-                };
-            }
+                DbId = id,
+                Group = group,
+                Origin = null!,
+                Name = name,
+                Content = content,
+                Retries = _capOptions.Value.FailedRetryCount,
+                Added = DateTime.Now,
+                ExpiresAt = DateTime.Now.AddDays(15),
+                StatusName = StatusName.Failed
+            };
         }
 
         public MediumMessage StoreReceivedMessage(string name, string @group, Message message)
@@ -107,21 +102,19 @@ namespace DotNetCore.CAP.InMemoryStorage
                 Retries = 0
             };
 
-            lock (ReceivedMessages)
+            ReceivedMessages[mdMessage.DbId] = new MemoryMessage
             {
-                ReceivedMessages[mdMessage.DbId] = new MemoryMessage
-                {
-                    DbId = mdMessage.DbId,
-                    Origin = mdMessage.Origin,
-                    Group = group,
-                    Name = name,
-                    Content = _serializer.Serialize(mdMessage.Origin),
-                    Retries = mdMessage.Retries,
-                    Added = mdMessage.Added,
-                    ExpiresAt = mdMessage.ExpiresAt,
-                    StatusName = StatusName.Scheduled
-                };
-            }
+                DbId = mdMessage.DbId,
+                Origin = mdMessage.Origin,
+                Group = group,
+                Name = name,
+                Content = _serializer.Serialize(mdMessage.Origin),
+                Retries = mdMessage.Retries,
+                Added = mdMessage.Added,
+                ExpiresAt = mdMessage.ExpiresAt,
+                StatusName = StatusName.Scheduled
+            };
+
             return mdMessage;
         }
 
@@ -131,38 +124,31 @@ namespace DotNetCore.CAP.InMemoryStorage
             var removed = 0;
             if (table == nameof(PublishedMessages))
             {
-                lock (PublishedMessages)
-                {
-                    var ids = PublishedMessages.Values
-                        .Where(x => x.ExpiresAt < timeout)
-                        .Select(x => x.DbId)
-                        .Take(batchCount);
+                var ids = PublishedMessages.Values
+                    .Where(x => x.ExpiresAt < timeout)
+                    .Select(x => x.DbId)
+                    .Take(batchCount);
 
-                    foreach (var id in ids)
+                foreach (var id in ids)
+                {
+                    if (PublishedMessages.TryRemove(id, out _))
                     {
-                        if (PublishedMessages.Remove(id))
-                        {
-                            removed++;
-                        }
+                        removed++;
                     }
                 }
-
             }
             else
             {
-                lock (ReceivedMessages)
-                {
-                    var ids = ReceivedMessages.Values
-                        .Where(x => x.ExpiresAt < timeout)
-                        .Select(x => x.DbId)
-                        .Take(batchCount);
+                var ids = ReceivedMessages.Values
+                    .Where(x => x.ExpiresAt < timeout)
+                    .Select(x => x.DbId)
+                    .Take(batchCount);
 
-                    foreach (var id in ids)
+                foreach (var id in ids)
+                {
+                    if (ReceivedMessages.TryRemove(id, out _))
                     {
-                        if (ReceivedMessages.Remove(id))
-                        {
-                            removed++;
-                        }
+                        removed++;
                     }
                 }
             }
@@ -172,17 +158,12 @@ namespace DotNetCore.CAP.InMemoryStorage
 
         public Task<IEnumerable<MediumMessage>> GetPublishedMessagesOfNeedRetry()
         {
-            IEnumerable<MediumMessage> result;
-
-            lock (PublishedMessages)
-            {
-                result = PublishedMessages.Values
+            IEnumerable<MediumMessage> result = PublishedMessages.Values
                 .Where(x => x.Retries < _capOptions.Value.FailedRetryCount
                             && x.Added < DateTime.Now.AddSeconds(-10)
                             && (x.StatusName == StatusName.Scheduled || x.StatusName == StatusName.Failed))
                 .Take(200)
                 .Select(x => (MediumMessage)x).ToList();
-            }
 
             foreach (var message in result)
             {
@@ -194,17 +175,12 @@ namespace DotNetCore.CAP.InMemoryStorage
 
         public Task<IEnumerable<MediumMessage>> GetReceivedMessagesOfNeedRetry()
         {
-            IEnumerable<MediumMessage> result;
-
-            lock (ReceivedMessages)
-            {
-                result = ReceivedMessages.Values
-                    .Where(x => x.Retries < _capOptions.Value.FailedRetryCount
-                                && x.Added < DateTime.Now.AddSeconds(-10)
-                                && (x.StatusName == StatusName.Scheduled || x.StatusName == StatusName.Failed))
-                    .Take(200)
-                    .Select(x => (MediumMessage)x).ToList();
-            }
+            IEnumerable<MediumMessage> result = ReceivedMessages.Values
+                .Where(x => x.Retries < _capOptions.Value.FailedRetryCount
+                            && x.Added < DateTime.Now.AddSeconds(-10)
+                            && (x.StatusName == StatusName.Scheduled || x.StatusName == StatusName.Failed))
+                .Take(200)
+                .Select(x => (MediumMessage)x).ToList();
 
             foreach (var message in result)
             {