Micro optimization by using is null (#1070)

src/NLog.Web.AspNetCore/AspNetExtensions.cs

@@ -377,7 +377,7 @@ private static NLogLoggerProvider CreateNLogLoggerProvider(IServiceProvider serv
 
             var configuration = SetupNLogConfigSettings(serviceProvider, hostConfiguration, provider.LogFactory);
 
-            if (configuration != null && (!ReferenceEquals(configuration, hostConfiguration) || options == null))
+            if (configuration != null && (!ReferenceEquals(configuration, hostConfiguration) || options is null))
             {
                 provider.Configure(configuration.GetSection("Logging:NLog"));
             }

src/NLog.Web.AspNetCore/LayoutRenderers/AspNetRequestTlsHandshakeLayoutRenderer.cs

@@ -38,9 +38,7 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var tlsHandshake = HttpContextAccessor.HttpContext.TryGetFeature<ITlsHandshakeFeature>();
             if (tlsHandshake is null)
-            {
                 return;
-            }
 
             switch (Property)
             {

src/NLog.Web.AspNetCore/LayoutRenderers/AspNetRequestTlsTokenBindingLayoutRenderer.cs

@@ -42,9 +42,7 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var tlsTokenBinding = HttpContextAccessor.HttpContext.TryGetFeature<ITlsTokenBindingFeature>();
             if (tlsTokenBinding is null)
-            {
                 return;
-            }
 
             switch (Property)
             {

src/NLog.Web.AspNetCore/LayoutRenderers/AspNetRequestTrailersLayoutRenderer.cs

@@ -52,14 +52,10 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var httpRequestTrailers = HttpContextAccessor.HttpContext.TryGetFeature<IHttpRequestTrailersFeature>();
             if (httpRequestTrailers is null)
-            {
                 return;
-            }
 
-            if(!httpRequestTrailers.Available)
-            {
+            if (!httpRequestTrailers.Available)
                 return;
-            }
 
             var trailers = httpRequestTrailers.Trailers;
             if (trailers?.Count > 0)

src/NLog.Web/LayoutRenderers/AspNetApplicationValueLayoutRenderer.cs

@@ -72,21 +72,15 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var item = Item;
             if (item is null)
-            {
                 return;
-            }
 
             var application = HttpContextAccessor.HttpContext.Application;
             if (application is null)
-            {
                 return;
-            }
 
             var value = application[item];
             if (value is null)
-            {
                 return;
-            }
 
             if (!(ObjectPath is null))
             {

src/NLog.Web/NLogRequestLoggingModule.cs

@@ -80,16 +80,16 @@ void IHttpModule.Dispose()
 
         private bool IsSlowHttpRequest(HttpContext httpContext)
         {
-            if (httpContext != null)
+            if (httpContext is null)
+                return false;
+
+            var timestamp = httpContext.Timestamp;
+            if (timestamp > DateTime.MinValue)
             {
-                var timestamp = httpContext.Timestamp;
-                if (timestamp > DateTime.MinValue)
+                var currentDuration = DateTime.UtcNow - timestamp.ToUniversalTime();
+                if (currentDuration > _durationThresholdMs)
                 {
-                    var currentDuration = DateTime.UtcNow - timestamp.ToUniversalTime();
-                    if (currentDuration > _durationThresholdMs)
-                    {
-                        return true;
-                    }
+                    return true;
                 }
             }
 

src/NLog.Web/Targets/AspNetTrace.cs

@@ -36,11 +36,8 @@ public AspNetTraceTarget()
         protected override void Write(LogEventInfo logEvent)
         {
             HttpContext context = HttpContext.Current;
-
-            if (context == null)
-            {
+            if (context is null)
                 return;
-            }
 
             if (logEvent.Level >= LogLevel.Warn)
             {

src/Shared/Internal/HttpContextExtensions.cs

@@ -107,34 +107,25 @@ internal static T TryGetFeature<T>(this HttpContext context) where T : class
         internal static string GetString(this ISession session, string key)
         {
             if (!session.TryGetValue(key, out var data))
-            {
                 return null;
-            }
 
-            if (data == null)
-            {
+            if (data is null)
                 return null;
-            }
 
             if (data.Length == 0)
-            {
                 return string.Empty;
-            }
 
             return Encoding.UTF8.GetString(data);
         }
 
         public static int? GetInt32(this ISession session, string key)
         {
             if (!session.TryGetValue(key, out var data))
-            {
                 return null;
-            }
 
-            if (data == null || data.Length < 4)
-            {
+            if (data is null || data.Length < 4)
                 return null;
-            }
+
             return data[0] << 24 | data[1] << 16 | data[2] << 8 | data[3];
         }
 #endif
@@ -143,7 +134,7 @@ internal static string GetString(this ISession session, string key)
         internal static HttpSessionStateBase TryGetSession(this HttpContextBase context)
         {
             var session = context?.Session;
-            if (session == null)
+            if (session is null)
                 InternalLogger.Debug("HttpContext Session Lookup returned null");
             return session;
         }

src/Shared/Internal/HttpHeaderCollectionValues.cs

@@ -14,7 +14,7 @@ internal static class HttpHeaderCollectionValues
 #if ASP_NET_CORE
         internal static IEnumerable<KeyValuePair<string, string>> GetHeaderValues(IHeaderDictionary headers, List<string> itemNames, ISet<string> excludeNames)
         {
-            bool checkForExclude = (itemNames == null || itemNames.Count == 0) && excludeNames?.Count > 0;
+            bool checkForExclude = (itemNames is null || itemNames.Count == 0) && excludeNames?.Count > 0;
             var headerNames = itemNames?.Count > 0 ? itemNames : headers.Keys;
             foreach (var headerName in headerNames)
             {
@@ -32,18 +32,16 @@ internal static IEnumerable<KeyValuePair<string, string>> GetHeaderValues(IHeade
 #else
         internal static IEnumerable<KeyValuePair<string, string>> GetHeaderValues(NameValueCollection headers, List<string> itemNames, HashSet<string> excludeNames)
         {
-            bool checkForExclude = (itemNames == null || itemNames.Count == 0) && excludeNames?.Count > 0;
+            bool checkForExclude = (itemNames is null || itemNames.Count == 0) && excludeNames?.Count > 0;
             var headerNames = itemNames?.Count > 0 ? itemNames : headers.Keys.Cast<string>();
             foreach (var headerName in headerNames)
             {
                 if (checkForExclude && excludeNames.Contains(headerName))
                     continue;
 
                 var headerValue = headers[headerName];
-                if (headerValue == null)
-                {
+                if (headerValue is null)
                     continue;
-                }
 
                 yield return new KeyValuePair<string, string>(headerName, headerValue);
             }

src/Shared/LayoutRenderers/AspNetItemValueLayoutRenderer.cs

@@ -90,15 +90,11 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var item = Item;
             if (string.IsNullOrEmpty(item))
-            {
                 return;
-            }
 
             var httpContext = HttpContextAccessor.HttpContext;
             if (httpContext is null)
-            {
                 return;
-            }
 
             object value = null;
 

src/Shared/LayoutRenderers/AspNetRequestContentTypeLayoutRenderer.cs

@@ -18,8 +18,8 @@ public class AspNetRequestContentTypeLayoutRenderer : AspNetLayoutRendererBase
         /// <inheritdoc/>
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
-            var request = HttpContextAccessor.HttpContext.TryGetRequest();
-            var contentType = request?.ContentType;
+            var httpRequest = HttpContextAccessor.HttpContext.TryGetRequest();
+            var contentType = httpRequest?.ContentType;
             builder.Append(contentType);
         }
     }

src/Shared/LayoutRenderers/AspNetRequestDurationLayoutRenderer.cs

@@ -38,7 +38,7 @@ public class AspNetRequestDurationLayoutRenderer : AspNetLayoutRendererBase
         /// <inheritdoc/>
         protected override void InitializeLayoutRenderer()
         {
-            if (DurationMsFormat == null && string.IsNullOrEmpty(Format) && ReferenceEquals(Culture, CultureInfo.InvariantCulture))
+            if (DurationMsFormat is null && string.IsNullOrEmpty(Format) && ReferenceEquals(Culture, CultureInfo.InvariantCulture))
             {
                 System.Threading.Interlocked.CompareExchange(ref DurationMsFormat, Enumerable.Range(0, 1000).Select(i => i.ToString(CultureInfo.InvariantCulture)).ToArray(), null);
             }
@@ -64,10 +64,8 @@ protected override void InitializeLayoutRenderer()
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var context = HttpContextAccessor.HttpContext;
-            if (context == null)
-            {
+            if (context is null)
                 return;
-            }
 
 #if ASP_NET_CORE && !NETCOREAPP3_0_OR_GREATER
             _scopeTiming?.Render(logEvent, builder);

src/Shared/LayoutRenderers/AspNetRequestHostLayoutRenderer.cs

@@ -18,11 +18,11 @@ public class AspNetRequestHostLayoutRenderer : AspNetLayoutRendererBase
         /// <inheritdoc/>
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
-            var request = HttpContextAccessor.HttpContext.TryGetRequest();
+            var httpRequest = HttpContextAccessor.HttpContext.TryGetRequest();
 #if ASP_NET_CORE
-            var host = request?.Host.ToString();
+            var host = httpRequest?.Host.ToString();
 #else
-            var host = request?.UserHostName?.ToString();
+            var host = httpRequest?.UserHostName?.ToString();
 #endif
             builder.Append(host);
         }

src/Shared/LayoutRenderers/AspNetRequestIpLayoutRenderer.cs

@@ -62,18 +62,16 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var httpContext = HttpContextAccessor.HttpContext;
 
-            var request = httpContext.TryGetRequest();
-            if (request == null)
-            {
+            var httpRequest = httpContext.TryGetRequest();
+            if (httpRequest is null)
                 return;
-            }
 
-            var ip = CheckForwardedForHeader && ForwardedForHeader != null ? TryLookupForwardHeader(request, logEvent) : string.Empty;
+            var ip = CheckForwardedForHeader && ForwardedForHeader != null ? TryLookupForwardHeader(httpRequest, logEvent) : string.Empty;
 
             if (string.IsNullOrEmpty(ip))
             {
 #if !ASP_NET_CORE
-                ip = request.ServerVariables?["REMOTE_ADDR"];
+                ip = httpRequest.ServerVariables?["REMOTE_ADDR"];
 #else
                 ip = httpContext.Connection?.RemoteIpAddress?.ToString();
 #endif

src/Shared/LayoutRenderers/AspNetRequestLocalIpLayoutRenderer.cs

@@ -26,18 +26,15 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
 
 #if ASP_NET_CORE
             var connection = httpContext.TryGetConnection();
-            if (connection == null)
-            {
+            if (connection is null)
                 return;
-            }
 
             builder.Append(connection.LocalIpAddress?.ToString());
 #else
             var request = httpContext.TryGetRequest();
-            if (request == null)
-            {
+            if (request is null)
                 return;
-            }
+
             builder.Append(request.ServerVariables?["LOCAL_ADDR"]);
 #endif
         }

src/Shared/LayoutRenderers/AspNetRequestLocalPortLayoutRenderer.cs

@@ -25,18 +25,15 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
             var httpContext = HttpContextAccessor.HttpContext;
 #if ASP_NET_CORE
             var connection = httpContext.TryGetConnection();
-            if (connection == null)
-            {
+            if (connection is null)
                 return;
-            }
 
             builder.Append(connection.LocalPort);
 #else
             var request = httpContext.TryGetRequest();
-            if (request == null)
-            {
+            if (request is null)
                 return;
-            }
+
             builder.Append(request.ServerVariables?["LOCAL_PORT"]);
 #endif
         }

src/Shared/LayoutRenderers/AspNetRequestPostedBodyLayoutRenderer.cs

@@ -44,10 +44,8 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
             }
 
             var items = HttpContextAccessor.HttpContext?.Items;
-            if (items == null || items.Count == 0)
-            {
+            if (items is null || items.Count == 0)
                 return;
-            }
 
 #if !ASP_NET_CORE
             if (items.Contains(NLogPostedRequestBodyKey))

src/Shared/LayoutRenderers/AspNetRequestQueryStringLayoutRenderer.cs

@@ -63,17 +63,15 @@ public AspNetQueryStringLayoutRenderer()
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var httpRequest = HttpContextAccessor.HttpContext.TryGetRequest();
-            if (httpRequest == null)
-            {
+            if (httpRequest is null)
                 return;
-            }
 
 #if !ASP_NET_CORE
             var queryStrings = httpRequest.QueryString;
 #else
             var queryStrings = httpRequest.Query;
 #endif
-            if (queryStrings == null || queryStrings.Count == 0)
+            if (queryStrings is null || queryStrings.Count == 0)
                 return;
 
             var queryStringKeys = Items?.Count > 0 ? Items :
@@ -82,7 +80,7 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
 #else
                 queryStrings.Keys;
 #endif
-            bool checkForExclude = (Items == null || Items.Count == 0) && Exclude?.Count > 0;
+            bool checkForExclude = (Items is null || Items.Count == 0) && Exclude?.Count > 0;
             var pairs = GetQueryStringValues(queryStrings, queryStringKeys, checkForExclude, Exclude);
             SerializePairs(pairs, builder, logEvent);
         }

src/Shared/LayoutRenderers/AspNetRequestReferrerRenderer.cs

@@ -25,10 +25,8 @@ public class AspNetRequestReferrerRenderer : AspNetLayoutRendererBase
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var httpRequest = HttpContextAccessor.HttpContext.TryGetRequest();
-            if (httpRequest == null)
-            {
+            if (httpRequest is null)
                 return;
-            }
 
             var referrer = string.Empty;
 #if !ASP_NET_CORE

src/Shared/LayoutRenderers/AspNetRequestRemotePortLayoutRenderer.cs

@@ -26,18 +26,15 @@ protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
 
 #if ASP_NET_CORE
             var connection = httpContext.TryGetConnection();
-            if (connection == null)
-            {
+            if (connection is null)
                 return;
-            }
 
             builder.Append(connection.RemotePort);
 #else
             var request = httpContext.TryGetRequest();
-            if (request == null)
-            {
+            if (request is null)
                 return;
-            }
+
             builder.Append(request.ServerVariables?["REMOTE_PORT"]);
 #endif
         }

src/Shared/LayoutRenderers/AspNetRequestRouteParametersRenderer.cs

@@ -45,10 +45,8 @@ public class AspNetRequestRouteParametersRenderer : AspNetLayoutMultiValueRender
         protected override void DoAppend(StringBuilder builder, LogEventInfo logEvent)
         {
             var context = HttpContextAccessor.HttpContext;
-            if (context == null)
-            {
+            if (context is null)
                 return;
-            }
 
             var pairs = GetPairs(context, Items);
             if (pairs != null)