Removed EmptyDefaultDictionary from MappedDiagnosticsContext (#4115)

snakefoot · web-flow · commit abf8d9efe9a0 · 2020-09-19T10:50:42.000+02:00
diff --git a/src/NLog/MappedDiagnosticsContext.cs b/src/NLog/MappedDiagnosticsContext.cs
@@ -31,15 +31,12 @@
 // THE POSSIBILITY OF SUCH DAMAGE.
 // 
 
-using System.Linq;
-
 namespace NLog
 {
     using System;
     using System.Collections.Generic;
-
-    using Config;
-    using Internal;
+    using NLog.Config;
+    using NLog.Internal;
 
     /// <summary>
     /// Mapped Diagnostics Context - a thread-local structure that keeps a dictionary
@@ -49,8 +46,6 @@ public static class MappedDiagnosticsContext
     {
         private static readonly object DataSlot = ThreadLocalStorageHelper.AllocateDataSlot();
 
-        private static readonly IDictionary<string, object> EmptyDefaultDictionary = new SortHelpers.ReadOnlySingleBucketDictionary<string, object>();
-
         private sealed class ItemRemover : IDisposable
         {
             private readonly string _item;
@@ -78,11 +73,7 @@ public void Dispose()
         /// <returns></returns>
         private static IDictionary<string, object> GetThreadDictionary(bool create = true)
         {
-            var dictionary = ThreadLocalStorageHelper.GetDataForSlot<Dictionary<string, object>>(DataSlot, create);
-            if (dictionary == null && !create)
-                return EmptyDefaultDictionary;
-
-            return dictionary;
+            return ThreadLocalStorageHelper.GetDataForSlot<Dictionary<string, object>>(DataSlot, create);
         }
 
         /// <summary>
@@ -159,12 +150,12 @@ public static string Get(string item, IFormatProvider formatProvider)
         /// <returns>The value of <paramref name="item"/>, if defined; otherwise <c>null</c>.</returns>
         public static object GetObject(string item)
         {
-            object o;
-
-            if (!GetThreadDictionary(false).TryGetValue(item, out o))
-                o = null;
-
-            return o;
+            var dictionary = GetThreadDictionary(false);
+            if (dictionary != null && dictionary.TryGetValue(item, out var o))
+            {
+                return o;
+            }
+            return null;
         }
 
         /// <summary>
@@ -173,7 +164,7 @@ public static object GetObject(string item)
         /// <returns>A set of the names of all items in current thread-MDC.</returns>
         public static ICollection<string> GetNames()
         {
-            return GetThreadDictionary(false).Keys;
+            return GetThreadDictionary(false)?.Keys ?? ArrayHelper.Empty<string>();
         }
 
         /// <summary>
@@ -183,7 +174,7 @@ public static ICollection<string> GetNames()
         /// <returns>A boolean indicating whether the specified <paramref name="item"/> exists in current thread MDC.</returns>
         public static bool Contains(string item)
         {
-            return GetThreadDictionary(false).ContainsKey(item);
+            return GetThreadDictionary(false)?.ContainsKey(item) == true;
         }
 
         /// <summary>
@@ -200,7 +191,7 @@ public static void Remove(string item)
         /// </summary>
         public static void Clear()
         {
-            GetThreadDictionary(true).Clear();
+            GetThreadDictionary(false)?.Clear();
         }
     }
 }
diff --git a/src/NLog/NestedDiagnosticsContext.cs b/src/NLog/NestedDiagnosticsContext.cs
@@ -174,7 +174,7 @@ public static object[] GetAllObjects()
         /// <summary>
         /// Resets the stack to the original count during <see cref="IDisposable.Dispose"/>.
         /// </summary>
-        private class StackPopper : IDisposable
+        private sealed class StackPopper : IDisposable
         {
             private readonly Stack<object> _stack;
             private readonly int _previousCount;

Original file line number	Diff line number	Diff line change
`@@ -31,15 +31,12 @@`
`31`	`31`	`// THE POSSIBILITY OF SUCH DAMAGE.`
`32`	`32`	`//`
`33`	`33`
`34`		`-using System.Linq;`
`35`		`-`
`36`	`34`	`namespace NLog`
`37`	`35`	`{`
`38`	`36`	`using System;`
`39`	`37`	`using System.Collections.Generic;`
`40`		`-`
`41`		`- using Config;`
`42`		`- using Internal;`
	`38`	`+ using NLog.Config;`
	`39`	`+ using NLog.Internal;`
`43`	`40`
`44`	`41`	`/// <summary>`
`45`	`42`	`/// Mapped Diagnostics Context - a thread-local structure that keeps a dictionary`
`@@ -49,8 +46,6 @@ public static class MappedDiagnosticsContext`
`49`	`46`	`{`
`50`	`47`	`private static readonly object DataSlot = ThreadLocalStorageHelper.AllocateDataSlot();`
`51`	`48`
`52`		`- private static readonly IDictionary<string, object> EmptyDefaultDictionary = new SortHelpers.ReadOnlySingleBucketDictionary<string, object>();`
`53`		`-`
`54`	`49`	`private sealed class ItemRemover : IDisposable`
`55`	`50`	`{`
`56`	`51`	`private readonly string _item;`
`@@ -78,11 +73,7 @@ public void Dispose()`
`78`	`73`	`/// <returns></returns>`
`79`	`74`	`private static IDictionary<string, object> GetThreadDictionary(bool create = true)`
`80`	`75`	`{`
`81`		`- var dictionary = ThreadLocalStorageHelper.GetDataForSlot<Dictionary<string, object>>(DataSlot, create);`
`82`		`- if (dictionary == null && !create)`
`83`		`- return EmptyDefaultDictionary;`
`84`		`-`
`85`		`- return dictionary;`
	`76`	`+ return ThreadLocalStorageHelper.GetDataForSlot<Dictionary<string, object>>(DataSlot, create);`
`86`	`77`	`}`
`87`	`78`
`88`	`79`	`/// <summary>`
`@@ -159,12 +150,12 @@ public static string Get(string item, IFormatProvider formatProvider)`
`159`	`150`	`/// <returns>The value of <paramref name="item"/>, if defined; otherwise <c>null</c>.</returns>`
`160`	`151`	`public static object GetObject(string item)`
`161`	`152`	`{`
`162`		`- object o;`
`163`		`-`
`164`		`- if (!GetThreadDictionary(false).TryGetValue(item, out o))`
`165`		`- o = null;`
`166`		`-`
`167`		`- return o;`
	`153`	`+ var dictionary = GetThreadDictionary(false);`
	`154`	`+ if (dictionary != null && dictionary.TryGetValue(item, out var o))`
	`155`	`+ {`
	`156`	`+ return o;`
	`157`	`+ }`
	`158`	`+ return null;`
`168`	`159`	`}`
`169`	`160`
`170`	`161`	`/// <summary>`
`@@ -173,7 +164,7 @@ public static object GetObject(string item)`
`173`	`164`	`/// <returns>A set of the names of all items in current thread-MDC.</returns>`
`174`	`165`	`public static ICollection<string> GetNames()`
`175`	`166`	`{`
`176`		`- return GetThreadDictionary(false).Keys;`
	`167`	`+ return GetThreadDictionary(false)?.Keys ?? ArrayHelper.Empty<string>();`
`177`	`168`	`}`
`178`	`169`
`179`	`170`	`/// <summary>`
`@@ -183,7 +174,7 @@ public static ICollection<string> GetNames()`
`183`	`174`	`/// <returns>A boolean indicating whether the specified <paramref name="item"/> exists in current thread MDC.</returns>`
`184`	`175`	`public static bool Contains(string item)`
`185`	`176`	`{`
`186`		`- return GetThreadDictionary(false).ContainsKey(item);`
	`177`	`+ return GetThreadDictionary(false)?.ContainsKey(item) == true;`
`187`	`178`	`}`
`188`	`179`
`189`	`180`	`/// <summary>`
`@@ -200,7 +191,7 @@ public static void Remove(string item)`
`200`	`191`	`/// </summary>`
`201`	`192`	`public static void Clear()`
`202`	`193`	`{`
`203`		`- GetThreadDictionary(true).Clear();`
	`194`	`+ GetThreadDictionary(false)?.Clear();`
`204`	`195`	`}`
`205`	`196`	`}`
`206`	`197`	`}`
Original file line number	Diff line number	Diff line change
`@@ -174,7 +174,7 @@ public static object[] GetAllObjects()`
`174`	`174`	`/// <summary>`
`175`	`175`	`/// Resets the stack to the original count during <see cref="IDisposable.Dispose"/>.`
`176`	`176`	`/// </summary>`
`177`		`- private class StackPopper : IDisposable`
	`177`	`+ private sealed class StackPopper : IDisposable`
`178`	`178`	`{`
`179`	`179`	`private readonly Stack<object> _stack;`
`180`	`180`	`private readonly int _previousCount;`