UPath performance improvements (#77)

* UPath performance improvements

* revert public API changes

* missed the documentation tags

* restore exception behaviour

---------

Co-authored-by: Sandro Bollhalder <[email protected]>

Author: bollhals

src/Zio.Tests/TestUPath.cs

@@ -41,6 +41,9 @@ public class TestUPath
     [InlineData("...a/b../", "...a/b..")]
     [InlineData("...a/..", "")]
     [InlineData("...a/b/..", "...a")]
+    [InlineData("..a/b", "..a/b")]
+    [InlineData("c/..d", "c/..d")]
+    [InlineData("c/d..", "c/d..")]
     public void TestNormalize(string pathAsText, string expectedResult)
     {
         var path = new UPath(pathAsText);
@@ -67,6 +70,16 @@ public void TestEquals()
         Assert.False(pathInfo.Equals(null));
     }
 
+    [Fact]
+    public void TestIsNullAndEmpty()
+    {
+        Assert.True(default(UPath).IsNull);
+        Assert.False(default(UPath).IsEmpty);
+        Assert.True(new UPath("").IsEmpty);
+        Assert.False(new UPath("").IsNull);
+        Assert.False(new UPath("/").IsEmpty);
+    }
+
     [Fact]
     public void TestAbsoluteAndRelative()
     {
@@ -83,9 +96,6 @@ public void TestAbsoluteAndRelative()
         Assert.True(path.IsAbsolute);
 
         Assert.Equal(path, path.ToAbsolute());
-
-        path = new UPath();
-        Assert.True(path.IsNull);
     }
 
     [Theory]

src/Zio/FileSystemExtensions.cs

@@ -401,7 +401,7 @@ public static string[] ReadAllLines(this IFileSystem fs, UPath path)
             using (var reader = new StreamReader(stream))
             {
                 var lines = new List<string>();
-                string line;
+                string? line;
                 while ((line = reader.ReadLine()) != null)
                 {
                     lines.Add(line);
@@ -430,7 +430,7 @@ public static string[] ReadAllLines(this IFileSystem fs, UPath path, Encoding en
             using (var reader = new StreamReader(stream, encoding))
             {
                 var lines = new List<string>();
-                string line;
+                string? line;
                 while ((line = reader.ReadLine()) != null)
                 {
                     lines.Add(line);
@@ -601,8 +601,7 @@ public static IEnumerable<UPath> EnumerateDirectories(this IFileSystem fileSyste
     public static IEnumerable<UPath> EnumerateDirectories(this IFileSystem fileSystem, UPath path, string searchPattern, SearchOption searchOption)
     {
         if (searchPattern is null) throw new ArgumentNullException(nameof(searchPattern));
-        foreach (var subPath in fileSystem.EnumeratePaths(path, searchPattern, searchOption, SearchTarget.Directory))
-            yield return subPath;
+        return fileSystem.EnumeratePaths(path, searchPattern, searchOption, SearchTarget.Directory);
     }
 
     /// <summary>
@@ -644,8 +643,7 @@ public static IEnumerable<UPath> EnumerateFiles(this IFileSystem fileSystem, UPa
     public static IEnumerable<UPath> EnumerateFiles(this IFileSystem fileSystem, UPath path, string searchPattern, SearchOption searchOption)
     {
         if (searchPattern is null) throw new ArgumentNullException(nameof(searchPattern));
-        foreach (var subPath in fileSystem.EnumeratePaths(path, searchPattern, searchOption, SearchTarget.File))
-            yield return subPath;
+        return fileSystem.EnumeratePaths(path, searchPattern, searchOption, SearchTarget.File);
     }
 
     /// <summary>

src/Zio/FileSystems/FileSystem.cs

@@ -612,7 +612,12 @@ private void AssertNotDisposed()
     {
         if (IsDisposing || IsDisposed)
         {
-            throw new ObjectDisposedException($"This instance `{GetType()}` is already disposed.");
+            Throw(this.GetType());
+        }
+
+        static void Throw(Type type)
+        {
+            throw new ObjectDisposedException($"This instance `{type}` is already disposed.");
         }
     }
 

src/Zio/FileSystems/PhysicalFileSystem.cs

@@ -815,9 +815,7 @@ protected override string ConvertPathToInternalImpl(UPath path)
             if (absolutePath.Length > DrivePrefixOnWindows.Length + 1)
                 builder.Append(absolutePath.Replace(UPath.DirectorySeparator, '\\').Substring(DrivePrefixOnWindows.Length + 2));
 
-            var result = builder.ToString();
-            builder.Length = 0;
-            return result;
+            return builder.ToString();
         }
         return absolutePath;
     }
@@ -841,9 +839,7 @@ protected override UPath ConvertPathFromInternalImpl(string innerPath)
             if (absolutePath.Length > 2)
                 builder.Append(absolutePath.Substring(2));
 
-            var result = builder.ToString();
-            builder.Length = 0;
-            return new UPath(result);
+            return new UPath(builder.ToString());
         }
         return innerPath;
     }