Added TrimMemory to the ResourceLimits (#1854).

Author: dlemstra

src/Magick.NET.Core/IResourceLimits.cs

@@ -1,6 +1,10 @@
 // Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
 // Licensed under the Apache License, Version 2.0.
 
+#if !NETSTANDARD2_0
+using System.Runtime.Versioning;
+#endif
+
 namespace ImageMagick;
 
 /// <summary>
@@ -75,4 +79,14 @@ public interface IResourceLimits
     /// </summary>
     /// <param name="percentage">The percentage to use.</param>
     void LimitMemory(Percentage percentage);
+
+    /// <summary>
+    /// Trims unused heap memory and returns it to the operating system, potentially reducing
+    /// the process memory footprint.
+    /// </summary>
+    /// <returns>true if memory was successfully released; otherwise, false.</returns>
+#if !NETSTANDARD2_0
+    [UnsupportedOSPlatform("windows")]
+#endif
+    bool TrimMemory();
 }

src/Magick.NET/Native/ResourceLimits.cs

@@ -58,5 +58,7 @@ private static partial class NativeResourceLimits
         public static partial void Width_Set(ulong value);
 
         public static partial void LimitMemory(double percentage);
+
+        public static partial bool TrimMemory();
     }
 }

src/Magick.NET/ResourceLimits.cs

@@ -1,6 +1,12 @@
 // Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
+
+#if !NETSTANDARD2_0
+using System.Runtime.Versioning;
+#endif
+
 namespace ImageMagick;
 
 /// <summary>
@@ -229,11 +235,38 @@ public static void LimitMemory(Percentage percentage)
         NativeResourceLimits.LimitMemory((double)percentage / 100.0);
     }
 
+    /// <summary>
+    /// Trims unused heap memory and returns it to the operating system, potentially reducing
+    /// the process memory footprint.
+    /// </summary>
+    /// <returns>true if memory was successfully released; otherwise, false.</returns>
+#if !NETSTANDARD2_0
+    [UnsupportedOSPlatform("windows")]
+#endif
+    public static bool TrimMemory()
+    {
+        if (Runtime.IsWindows)
+            throw new NotSupportedException();
+
+        return NativeResourceLimits.TrimMemory();
+    }
+
     /// <summary>
     /// Set the maximum percentage of <see cref="Memory"/> that can be used for image data.
     /// This also changes the <see cref="Area"/> limit to four times the number of bytes.
     /// </summary>
     /// <param name="percentage">The percentage to use.</param>
     void IResourceLimits.LimitMemory(Percentage percentage)
         => LimitMemory(percentage);
+
+    /// <summary>
+    /// Trims unused heap memory and returns it to the operating system, potentially reducing
+    /// the process memory footprint.
+    /// </summary>
+    /// <returns>true if memory was successfully released; otherwise, false.</returns>
+#if !NETSTANDARD2_0
+    [UnsupportedOSPlatform("windows")]
+#endif
+    bool IResourceLimits.TrimMemory()
+        => TrimMemory();
 }

tests/Magick.NET.Tests/ResourceLimitsTests/TheTrimMemoryMethod.cs

@@ -0,0 +1,42 @@
+// Copyright Dirk Lemstra https://github.com/dlemstra/Magick.NET.
+// Licensed under the Apache License, Version 2.0.
+
+using System;
+using ImageMagick;
+using Xunit;
+
+namespace Magick.NET.Tests;
+
+#pragma warning disable CA1416 // Validate platform compatibility
+
+public partial class ResourceLimitsTests
+{
+    [Collection(nameof(IsolatedUnitTest))]
+    public class TheTrimMemoryMethod
+    {
+        [Fact]
+        public void ShouldThrowExceptionOnWindows()
+        {
+            Assert.SkipUnless(Runtime.IsWindows, "Will only throw exception on Windows.");
+
+            Assert.Throws<NotSupportedException>(static () => ResourceLimits.TrimMemory());
+        }
+
+        [Fact]
+        public void ShouldReturnTrueOrFalse()
+        {
+            Assert.SkipWhen(Runtime.IsWindows, "Will throw exception on Windows.");
+
+            if (Runtime.IsWindows)
+                return;
+
+            var result = ResourceLimits.TrimMemory();
+            if (result)
+                Assert.True(result);
+            else
+                Assert.False(result);
+        }
+    }
+}
+
+#pragma warning restore CA1416 // Validate platform compatibility