Fixed possible null reference issues

Author: axunonb

Src/Axuno.VirtualFileSystem/Axuno.VirtualFileSystem.csproj

@@ -6,16 +6,16 @@
         <SignAssembly>true</SignAssembly>
         <!-- sn -k Axuno.VirtualFileSystem.snk -->
         <AssemblyOriginatorKeyFile>Axuno.VirtualFileSystem.snk</AssemblyOriginatorKeyFile>
-        <Version>1.0.0</Version>
+        <Version>1.0.1</Version>
         <Authors>axuno gGmbH</Authors>
         <Company>axuno gGmbH</Company>
         <PackageLicenseExpression>LGPL-3.0-only</PackageLicenseExpression>
         <PackageIcon>VirtualFileSystem.png</PackageIcon>
         <RepositoryUrl>https://github.com/axuno/Axuno.VirtualFileSystem</RepositoryUrl>
         <RepositoryType>Git</RepositoryType>
         <PackageTags>virtual file system netstandard c#</PackageTags>
-        <PackageReleaseNotes>Added unit tests
-Bumped to v1.0.0</PackageReleaseNotes>
+        <PackageReleaseNotes>Fixed possible null reference issues
+Bumped to v1.0.1</PackageReleaseNotes>
         <Copyright>© 2013 - 2021 Volosoft. Open source license with LGPLv3.0</Copyright>
         <Description>The Virtual File System makes it possible to manage files that do not exist on a physical file system (e.g. disk).
 
@@ -24,7 +24,7 @@ Bumped to v1.0.0</PackageReleaseNotes>
 * Virtual files can be used just like static files in an application.
 * JavaScript, CSS, image files and all other file types can be embedded into assemblies and used just like the static files.
 
-The library is a modified version of Volo.Abp.VirtualFileSystem 4.1</Description>
+The library is a modified version of Volo.Abp.VirtualFileSystem 4.2</Description>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
         <PackageRequireLicenseAcceptance>true</PackageRequireLicenseAcceptance>
     </PropertyGroup>

Src/Axuno.VirtualFileSystem/DictionaryExtensions.cs

@@ -10,7 +10,7 @@ namespace Axuno.VirtualFileSystem
     public static class DictionaryExtensions
     {
         /// <summary>
-        /// This method is used to try to get a value in a dictionary if it does exists.
+        /// This method is used to try to get a value in a dictionary if it exists.
         /// </summary>
         /// <typeparam name="T">Type of the value</typeparam>
         /// <param name="dictionary">The collection object</param>
@@ -19,7 +19,7 @@ public static class DictionaryExtensions
         /// <returns>True if key does exists in the dictionary</returns>
         internal static bool TryGetValue<T>(this IDictionary<string, object> dictionary, string key, out T value) where T : notnull
         {
-            if (dictionary.TryGetValue(key, out object valueObj) && valueObj is T obj)
+            if (dictionary.TryGetValue(key, out var valueObj) && valueObj is T obj)
             {
                 value = obj;
                 return true;
@@ -37,9 +37,9 @@ internal static bool TryGetValue<T>(this IDictionary<string, object> dictionary,
         /// <typeparam name="TKey">Type of the key</typeparam>
         /// <typeparam name="TValue">Type of the value</typeparam>
         /// <returns>Value if found, default if can not found.</returns>
-        public static TValue GetOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey key)  where TValue : notnull
+        public static TValue GetOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dictionary, TKey key)  where TValue : notnull where  TKey : notnull
         {
-            return dictionary.TryGetValue(key, out var obj) ? obj : default!;
+            return (dictionary.TryGetValue(key, out var obj) ? obj : default) ?? throw new NullReferenceException($"A {typeof(TValue)} has null a default");
         }
 
         /// <summary>
@@ -76,7 +76,7 @@ public static TValue GetOrDefault<TKey, TValue>(this IReadOnlyDictionary<TKey, T
         /// <typeparam name="TKey">Type of the key</typeparam>
         /// <typeparam name="TValue">Type of the value</typeparam>
         /// <returns>Value if found, default if can not found.</returns>
-        public static TValue GetOrDefault<TKey, TValue>(this ConcurrentDictionary<TKey, TValue> dictionary, TKey key) where TValue : notnull
+        public static TValue GetOrDefault<TKey, TValue>(this ConcurrentDictionary<TKey, TValue> dictionary, TKey key) where TValue : notnull where TKey : notnull
         {
             return dictionary.TryGetValue(key, out var obj) ? obj : default!;
         }

Src/Axuno.VirtualFileSystem/DynamicFileProvider.cs

@@ -6,7 +6,6 @@
 using Microsoft.Extensions.FileProviders;
 using Microsoft.Extensions.Primitives;
 
-
 namespace Axuno.VirtualFileSystem
 {
     /// <summary>
@@ -19,18 +18,35 @@ namespace Axuno.VirtualFileSystem
     /// </remarks>
     public class DynamicFileProvider : DictionaryBasedFileProvider, IDynamicFileProvider
     {
+        /// <summary>
+        /// Gets the <see cref="IDictionary{TKey,TValue}"/> for dynamic files.
+        /// </summary>
+        /// <remarks>This property can be overridden in a derived class.</remarks>
         protected override IDictionary<string, IFileInfo> Files => DynamicFiles;
 
+        /// <summary>
+        /// Gets dynamic files as a <see cref="ConcurrentDictionary{TKey,TValue}"/>.
+        /// </summary>
         protected ConcurrentDictionary<string, IFileInfo> DynamicFiles { get; }
 
+        /// <summary>
+        /// Gets the <see cref="ConcurrentDictionary{TKey,TValue}"/> for <see cref="ChangeTokenInfo"/>s.
+        /// </summary>
         protected ConcurrentDictionary<string, ChangeTokenInfo> FilePathTokenLookup { get; }
 
+        /// <summary>
+        /// CTOR.
+        /// </summary>
         public DynamicFileProvider()
         {
             FilePathTokenLookup = new ConcurrentDictionary<string, ChangeTokenInfo>(StringComparer.OrdinalIgnoreCase);;
             DynamicFiles = new ConcurrentDictionary<string, IFileInfo>();
         }
 
+        /// <summary>
+        /// Updates the existing <see cref="IFileInfo"/> or inserts a new one.
+        /// </summary>
+        /// <param name="fileInfo"></param>
         public void AddOrUpdate(IFileInfo fileInfo)
         {
             var filePath = fileInfo.GetVirtualOrPhysicalPath();
@@ -39,6 +55,11 @@ public void AddOrUpdate(IFileInfo fileInfo)
             ReportChange(filePath);
         }
 
+        /// <summary>
+        /// Deletes a dynamic file.
+        /// </summary>
+        /// <param name="filePath"></param>
+        /// <returns><see langword="true"/>, if the dynamic file was deleted.</returns>
         public bool Delete(string filePath)
         {
             if (!DynamicFiles.TryRemove(filePath, out _))
@@ -50,6 +71,11 @@ public bool Delete(string filePath)
             return true;
         }
 
+        /// <summary>
+        /// Gets the <see cref="IChangeToken"/> for the given filter.
+        /// </summary>
+        /// <param name="filter"></param>
+        /// <returns>The <see cref="IChangeToken"/> for the given filter.</returns>
         public override IChangeToken Watch(string filter)
         {
             return GetOrAddChangeToken(filter);
@@ -76,8 +102,16 @@ private void ReportChange(string filePath)
             }
         }
 
+        /// <summary>
+        /// The <see cref="ChangeTokenInfo"/> structure.
+        /// </summary>
         protected struct ChangeTokenInfo
         {
+            /// <summary>
+            /// CTOR.
+            /// </summary>
+            /// <param name="tokenSource"></param>
+            /// <param name="changeToken"></param>
             public ChangeTokenInfo(
                 CancellationTokenSource tokenSource,
                 CancellationChangeToken changeToken)
@@ -86,8 +120,14 @@ public ChangeTokenInfo(
                 ChangeToken = changeToken;
             }
 
+            /// <summary>
+            /// Gets the <see cref="CancellationTokenSource"/>.
+            /// </summary>
             public CancellationTokenSource TokenSource { get; }
 
+            /// <summary>
+            /// Gets the <see cref="ChangeToken"/>.
+            /// </summary>
             public CancellationChangeToken ChangeToken { get; }
         }
     }

Src/Axuno.VirtualFileSystem/Embedded/EmbeddedResourceFileInfo.cs

@@ -10,6 +10,29 @@ namespace Axuno.VirtualFileSystem.Embedded
     /// </summary>
     public class EmbeddedResourceFileInfo : IFileInfo
     {
+        /// <summary>
+        /// CTOR.
+        /// </summary>
+        /// <param name="assembly"></param>
+        /// <param name="resourcePath"></param>
+        /// <param name="virtualPath"></param>
+        /// <param name="name"></param>
+        /// <param name="lastModified"></param>
+        public EmbeddedResourceFileInfo(
+            Assembly assembly,
+            string resourcePath,
+            string virtualPath,
+            string name,
+            DateTimeOffset lastModified)
+        {
+            _assembly = assembly;
+            _resourcePath = resourcePath;
+
+            VirtualPath = virtualPath;
+            Name = name;
+            LastModified = lastModified;
+        }
+        
         public bool Exists => true;
 
         public long Length
@@ -18,13 +41,11 @@ public long Length
             {
                 if (!_length.HasValue)
                 {
-                    using (var stream = _assembly.GetManifestResourceStream(_resourcePath))
-                    {
-                        _length = stream.Length;
-                    }
+                    using var stream = _assembly.GetManifestResourceStream(_resourcePath);
+                    _length = stream?.Length;
                 }
 
-                return _length.Value;
+                return 0;
             }
         }
         private long? _length;
@@ -36,7 +57,7 @@ public long Length
         public string Name { get; }
 
         /// <summary>
-        /// The time, in UTC.
+        /// Gets the <see cref="DateTimeOffset"/>.
         /// </summary>
         public DateTimeOffset LastModified { get; }
 
@@ -45,21 +66,6 @@ public long Length
         private readonly Assembly _assembly;
         private readonly string _resourcePath;
 
-        public EmbeddedResourceFileInfo(
-            Assembly assembly,
-            string resourcePath,
-            string virtualPath,
-            string name,
-            DateTimeOffset lastModified)
-        {
-            _assembly = assembly;
-            _resourcePath = resourcePath;
-
-            VirtualPath = virtualPath;
-            Name = name;
-            LastModified = lastModified;
-        }
-
         /// <inheritdoc />
         public Stream? CreateReadStream()
         {

Src/Axuno.VirtualFileSystem/StringExtensions.cs

@@ -85,8 +85,8 @@ public static string NormalizeLineEndings(this string str)
         /// <summary>
         /// Gets index of nth occurrence of a char in a string.
         /// </summary>
-        /// <param name="str">source string to be searched</param>
-        /// <param name="c">Char to search in <see cref="str"/></param>
+        /// <param name="str"></param>
+        /// <param name="c"></param>
         /// <param name="n">Count of the occurrence</param>
         public static int NthIndexOf(this string str, char c, int n)
         {
@@ -191,7 +191,7 @@ public static string ReplaceFirst(this string str, string search, string replace
                 return str;
             }
 
-            return str.Substring(0, pos) + replace + str.Substring(pos + search.Length);
+            return str.Substring(0, pos) + replace + str[(pos + search.Length)..];
         }
 
         /// <summary>
@@ -261,7 +261,7 @@ public static string ToCamelCase(this string str, bool useCurrentCulture = false
                 return useCurrentCulture ? str.ToLower() : str.ToLowerInvariant();
             }
 
-            return (useCurrentCulture ? char.ToLower(str[0]) : char.ToLowerInvariant(str[0])) + str.Substring(1);
+            return (useCurrentCulture ? char.ToLower(str[0]) : char.ToLowerInvariant(str[0])) + str[1..];
         }
 
         /// <summary>
@@ -399,19 +399,17 @@ public static T ToEnum<T>(this string value, bool ignoreCase)
 
         public static string ToMd5(this string str)
         {
-            using (var md5 = MD5.Create())
-            {
-                var inputBytes = Encoding.UTF8.GetBytes(str);
-                var hashBytes = md5.ComputeHash(inputBytes);
-
-                var sb = new StringBuilder();
-                foreach (var hashByte in hashBytes)
-                {
-                    sb.Append(hashByte.ToString("X2"));
-                }
+            using var md5 = MD5.Create();
+            var inputBytes = Encoding.UTF8.GetBytes(str);
+            var hashBytes = md5.ComputeHash(inputBytes);
 
-                return sb.ToString();
+            var sb = new StringBuilder();
+            foreach (var hashByte in hashBytes)
+            {
+                sb.Append(hashByte.ToString("X2"));
             }
+
+            return sb.ToString();
         }
 
         /// <summary>
@@ -432,7 +430,7 @@ public static string ToPascalCase(this string str, bool useCurrentCulture = fals
                 return useCurrentCulture ? str.ToUpper() : str.ToUpperInvariant();
             }
 
-            return (useCurrentCulture ? char.ToUpper(str[0]) : char.ToUpperInvariant(str[0])) + str.Substring(1);
+            return (useCurrentCulture ? char.ToUpper(str[0]) : char.ToUpperInvariant(str[0])) + str[1..];
         }
 
         /// <summary>
@@ -441,12 +439,7 @@ public static string ToPascalCase(this string str, bool useCurrentCulture = fals
         /// <exception cref="ArgumentNullException">Thrown if <paramref name="str"/> is null</exception>
         public static string Truncate(this string str, int maxLength)
         {
-            if (str.Length <= maxLength)
-            {
-                return str;
-            }
-
-            return str.Left(maxLength);
+            return str.Length <= maxLength ? str : str.Left(maxLength);
         }
 
         /// <summary>
@@ -455,12 +448,7 @@ public static string Truncate(this string str, int maxLength)
         /// <exception cref="ArgumentNullException">Thrown if <paramref name="str"/> is null</exception>
         public static string TruncateFromBeginning(this string str, int maxLength)
         {
-            if (str.Length <= maxLength)
-            {
-                return str;
-            }
-
-            return str.Right(maxLength);
+            return str.Length <= maxLength ? str : str.Right(maxLength);
         }
 
         /// <summary>