Fixed #3915: Use SemaphoreSlim in the LocalizedTemplateContentReaderFactory

framework/src/Volo.Abp.TextTemplating/Volo/Abp/TextTemplating/VirtualFiles/LocalizedTemplateContentReaderFactory.cs

@@ -1,6 +1,7 @@
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.Threading;
 using System.Threading.Tasks;
+using Nito.AsyncEx;
 using Volo.Abp.DependencyInjection;
 using Volo.Abp.VirtualFileSystem;
 
@@ -9,50 +10,33 @@ namespace Volo.Abp.TextTemplating.VirtualFiles
     public class LocalizedTemplateContentReaderFactory : ILocalizedTemplateContentReaderFactory, ISingletonDependency
     {
         private readonly IVirtualFileProvider _virtualFileProvider;
-        private readonly Dictionary<string, ILocalizedTemplateContentReader> _readerCache;
-        private readonly ReaderWriterLockSlim _lock;
+        private readonly ConcurrentDictionary<string, ILocalizedTemplateContentReader> _readerCache;
+        protected SemaphoreSlim SyncObj;
 
         public LocalizedTemplateContentReaderFactory(IVirtualFileProvider virtualFileProvider)
         {
             _virtualFileProvider = virtualFileProvider;
-            _readerCache = new Dictionary<string, ILocalizedTemplateContentReader>();
-            _lock = new ReaderWriterLockSlim(LockRecursionPolicy.NoRecursion);
+            _readerCache = new ConcurrentDictionary<string, ILocalizedTemplateContentReader>();
+            SyncObj = new SemaphoreSlim(1, 1);
         }
 
         public async Task<ILocalizedTemplateContentReader> CreateAsync(TemplateDefinition templateDefinition)
         {
-            _lock.EnterUpgradeableReadLock();
+            if (_readerCache.TryGetValue(templateDefinition.Name, out var reader))
+            {
+                return reader;
+            }
 
-            try
+            using (await SyncObj.LockAsync())
             {
-                var reader = _readerCache.GetOrDefault(templateDefinition.Name);
-                if (reader != null)
+                if (_readerCache.TryGetValue(templateDefinition.Name, out reader))
                 {
                     return reader;
                 }
 
-                _lock.EnterWriteLock();
-
-                try
-                {
-                    reader = await CreateInternalAsync(templateDefinition);
-                    _readerCache[templateDefinition.Name] = reader;
-                    return reader;
-                }
-                finally
-                {
-                    if (_lock.IsWriteLockHeld)
-                    {
-                        _lock.ExitWriteLock();
-                    }
-                }
-            }
-            finally
-            {
-                if (_lock.IsUpgradeableReadLockHeld)
-                {
-                    _lock.ExitUpgradeableReadLock();
-                }
+                reader = await CreateInternalAsync(templateDefinition);
+                _readerCache[templateDefinition.Name] = reader;
+                return reader;
             }
         }