Add DirectoryInfo.Clear (#63)

CHANGELOG.md

@@ -4,6 +4,7 @@
 ### Added
 - X10D: Added `MathUtility.InverseLerp(float, float, float)` and `MathUtility.InverseLerp(double, double, double)`
 - X10D: Added `Circle`, `CircleF`, `Cuboid`, `Ellipse`, `EllipseF`, `Line3D`, `Line`, `LineF`, `Polygon`, `PolygonF`, `Polyhedron`, and `Sphere`, to complement System.Drawing structs such as `Point` and `Rectangle`
+- X10D: Added `DirectoryInfo.Clear([bool])`
 - X10D: Added `IList<T>.RemoveRange(Range)`
 - X10D: Added `Point.ToSize()`
 - X10D: Added `Point.ToSizeF()`

X10D.Tests/src/IO/DirectoryInfoTests.cs

@@ -0,0 +1,83 @@
+using Microsoft.VisualStudio.TestTools.UnitTesting;
+using X10D.IO;
+
+namespace X10D.Tests.IO;
+
+[TestClass]
+public class DirectoryInfoTests
+{
+    [TestMethod]
+    public void Clear_ShouldClear_GivenValidDirectory()
+    {
+        string tempPath = Path.GetTempPath();
+        DirectoryInfo directory;
+        do
+        {
+            string tempDirectory = Path.Combine(tempPath, Guid.NewGuid().ToString());
+            directory = new DirectoryInfo(tempDirectory);
+        } while (directory.Exists);
+
+        directory.Create();
+        Assert.IsTrue(directory.Exists);
+
+        var file = new FileInfo(Path.Combine(directory.FullName, "file"));
+        file.Create().Close();
+
+        var childDirectory = new DirectoryInfo(Path.Combine(directory.FullName, "child"));
+        childDirectory.Create();
+
+        var childFile = new FileInfo(Path.Combine(childDirectory.FullName, "childFile"));
+        childFile.Create().Close();
+
+        Assert.AreEqual(1, directory.GetFiles().Length);
+        Assert.AreEqual(1, directory.GetDirectories().Length);
+        directory.Clear(false);
+        Assert.AreEqual(0, directory.GetFiles().Length);
+        Assert.AreEqual(0, directory.GetDirectories().Length);
+        Assert.IsTrue(directory.Exists);
+
+        directory.Delete();
+    }
+
+    [TestMethod]
+    public void Clear_ShouldDoNothing_GivenNonExistentDirectory()
+    {
+        var directory = new DirectoryInfo(@"/@12#3");
+        Assert.IsFalse(directory.Exists);
+        directory.Clear();
+    }
+
+    [TestMethod]
+    public void Clear_ShouldNotThrow_WhenThrowOnErrorIsFalse()
+    {
+        var directory = new DirectoryInfo(@"/@12#3");
+        Assert.IsFalse(directory.Exists);
+
+        directory.Clear();
+        directory.Clear(false);
+
+        Assert.IsTrue(true); // if this assertion passes, then the test passed
+    }
+
+    [TestMethod]
+    public void Clear_ShouldThrowArgumentNullException_GivenNull()
+    {
+        Assert.ThrowsException<ArgumentNullException>(() => ((DirectoryInfo?)null)!.Clear());
+        Assert.ThrowsException<ArgumentNullException>(() => ((DirectoryInfo?)null)!.Clear(true));
+    }
+
+    [TestMethod]
+    public void Clear_ShouldThrowDirectoryNotFoundException_GivenInvalidDirectory()
+    {
+        var directory = new DirectoryInfo(@"123:/@12#3");
+        Assert.ThrowsException<DirectoryNotFoundException>(() => directory.Clear(true));
+    }
+
+    [TestMethod]
+    public void Clear_ShouldThrowDirectoryNotFoundException_GivenNonExistentDirectory()
+    {
+        var directory = new DirectoryInfo(@"/@12#3");
+        Assert.IsFalse(directory.Exists);
+        Assert.ThrowsException<DirectoryNotFoundException>(() => directory.Clear(true));
+    }
+}

X10D/src/IO/DirectoryInfoExtensions.cs

@@ -0,0 +1,107 @@
+using System.Security;
+
+namespace X10D.IO;
+
+/// <summary>
+///     IO-related extension methods for <see cref="DirectoryInfo" />.
+/// </summary>
+public static class DirectoryInfoExtensions
+{
+    /// <summary>
+    ///     Removes all files and subdirectories in this directory, recursively, without deleting this directory.
+    /// </summary>
+    /// <param name="directory">The directory to clear.</param>
+    public static void Clear(this DirectoryInfo directory)
+    {
+        directory.Clear(false);
+    }
+
+    /// <summary>
+    ///     Removes all files and subdirectories in this directory, recursively, without deleting this directory.
+    /// </summary>
+    /// <param name="directory">The directory to clear.</param>
+    /// <param name="throwOnError">
+    ///     <see langword="true" /> to throw any exceptions which were caught during the operation; otherwise,
+    ///     <see langword="false." />
+    /// </param>
+    /// <exception cref="DirectoryNotFoundException">
+    ///     The directory described by this <see cref="DirectoryInfo" /> object does not exist or could not be found. This
+    ///     exception is not thrown if <paramref name="throwOnError" /> is <see langword="false" />.
+    /// </exception>
+    /// <exception cref="IOException">
+    ///     A target file is open or memory-mapped on a computer running Microsoft Windows NT.
+    ///     -or-
+    ///     There is an open handle on one of the files, and the operating system is Windows XP or earlier. This open handle can
+    ///     result from enumerating directories and files.
+    ///     -or-
+    ///     The directory is read-only.
+    ///     -or-
+    ///     The directory contains one or more files or subdirectories and recursive is false.
+    ///     -or-
+    ///     The directory is the application's current working directory.
+    ///     -or-
+    ///     There is an open handle on the directory or on one of its files, and the operating system is Windows XP or earlier.
+    ///     This open handle can result from enumerating directories and files.
+    ///     This exception is not thrown if <paramref name="throwOnError" /> is <see langword="false" />.
+    /// </exception>
+    /// <exception cref="SecurityException">
+    ///     The caller does not have the required permission. This exception is not thrown if <paramref name="throwOnError" /> is
+    ///     <see langword="false" />.
+    /// </exception>
+    /// <exception cref="UnauthorizedAccessException">This directory or one of its children contain a read-only file. This
+    ///     exception is not thrown if <paramref name="throwOnError" /> is <see langword="false" />.
+    /// </exception>
+    public static void Clear(this DirectoryInfo directory, bool throwOnError)
+    {
+#if NET6_0_OR_GREATER
+        ArgumentNullException.ThrowIfNull(directory);
+#else
+        if (directory is null)
+        {
+            throw new ArgumentNullException(nameof(directory));
+        }
+#endif
+
+        if (!directory.Exists)
+        {
+            if (throwOnError)
+            {
+                throw new DirectoryNotFoundException();
+            }
+
+            return;
+        }
+
+        foreach (FileInfo file in directory.EnumerateFiles())
+        {
+            try
+            {
+                file.Delete();
+            }
+            catch when (throwOnError)
+            {
+                throw;
+            }
+            catch
+            {
+                // do nothing
+            }
+        }
+
+        foreach (DirectoryInfo childDirectory in directory.EnumerateDirectories())
+        {
+            try
+            {
+                childDirectory.Delete(true);
+            }
+            catch when (throwOnError)
+            {
+                throw;
+            }
+            catch
+            {
+                // do nothing
+            }
+        }
+    }
+}