Merge pull request #548 from qmfrederik/fixes/dispose-housekeeping

Managed Git: .Dispose() housekeeping

Author: AArnott

src/NerdBank.GitVersioning/GitContext.cs

@@ -246,7 +246,10 @@ private protected static void FindGitPaths(string path, out string gitDirectory,
             }
         }
 
-        /// <inheritdoc />
+        /// <summary>
+        /// Disposes of native and managed resources associated by this object.
+        /// </summary>
+        /// <param name="disposing"><see langword="true" /> to dispose managed and native resources; <see langword="false" /> to only dispose of native resources.</param>
         protected virtual void Dispose(bool disposing)
         {
         }

src/NerdBank.GitVersioning/Managed/ManagedGitContext.cs

@@ -119,6 +119,17 @@ public override string GetShortUniqueCommitId(int minLength)
             return this.Repository.ShortenObjectId(this.Commit.Value.Sha, minLength);
         }
 
+        /// <inheritdoc/>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                this.Repository.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
         /// <summary>
         /// Encodes a commit from history in a <see cref="Version"/>
         /// so that the original commit can be found later.

src/NerdBank.GitVersioning/ManagedGit/GitPack.cs

@@ -259,6 +259,7 @@ public void Dispose()
 
             this.accessor.Dispose();
             this.packFile.Dispose();
+            this.cache.Dispose();
         }
 
         private long? GetOffset(GitObjectId objectId)

src/NerdBank.GitVersioning/ManagedGit/GitPackCache.cs

@@ -1,5 +1,6 @@
 #nullable enable
 
+using System;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Text;
@@ -12,7 +13,7 @@ namespace Nerdbank.GitVersioning.ManagedGit
     /// data from a <see cref="GitPack"/> can be potentially expensive: the data is
     /// compressed and can be deltified.
     /// </summary>
-    public abstract class GitPackCache
+    public abstract class GitPackCache : IDisposable
     {
         /// <summary>
         /// Attempts to retrieve a Git object from cache.
@@ -51,5 +52,20 @@ public abstract class GitPackCache
         /// A <see cref="Stream"/> which represents the cached entry.
         /// </returns>
         public abstract Stream Add(long offset, Stream stream);
+
+        /// <inheritdoc/>
+        public void Dispose()
+        {
+            this.Dispose(true);
+            GC.SuppressFinalize(this);
+        }
+
+        /// <summary>
+        /// Disposes of native and managed resources associated by this object.
+        /// </summary>
+        /// <param name="disposing"><see langword="true" /> to dispose managed and native resources; <see langword="false" /> to only dispose of native resources.</param>
+        protected virtual void Dispose(bool disposing)
+        {
+        }
     }
 }

src/NerdBank.GitVersioning/ManagedGit/GitPackMemoryCache.cs

@@ -3,6 +3,7 @@
 using System.Collections.Generic;
 using System.Diagnostics.CodeAnalysis;
 using System.IO;
+using System.Linq;
 using System.Text;
 
 namespace Nerdbank.GitVersioning.ManagedGit
@@ -55,5 +56,22 @@ public override void GetCacheStatistics(StringBuilder builder)
         {
             builder.AppendLine($"{this.cache.Count} items in cache");
         }
+
+        /// <inheritdoc/>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                while (this.cache.Count > 0)
+                {
+                    var key = this.cache.Keys.First();
+                    var stream = this.cache[key];
+                    stream.Dispose();
+                    this.cache.Remove(key);
+                }
+            }
+
+            base.Dispose(disposing);
+        }
     }
 }

src/NerdBank.GitVersioning/ManagedGit/GitPackMemoryCacheStream.cs

@@ -99,6 +99,17 @@ public override void Write(byte[] buffer, int offset, int count)
             throw new NotSupportedException();
         }
 
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                this.stream.Dispose();
+                this.cacheStream.Dispose();
+            }
+
+            base.Dispose(disposing);
+        }
+
         private void DisposeStreamIfRead()
         {
             if (this.cacheStream.Length == this.stream.Length)

src/NerdBank.GitVersioning/ManagedGit/MemoryMappedStream.cs

@@ -13,6 +13,7 @@ public unsafe class MemoryMappedStream : Stream
         private readonly long length;
         private long position;
         private byte* ptr;
+        private bool disposed;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="MemoryMappedStream"/> class.
@@ -57,6 +58,11 @@ public override void Flush()
         /// <inheritdoc/>
         public override int Read(byte[] buffer, int offset, int count)
         {
+            if (this.disposed)
+            {
+                throw new ObjectDisposedException(nameof(MemoryMappedStream));
+            }
+
             int read = (int)Math.Min(count, this.length - this.position);
 
             new Span<byte>(this.ptr + this.position, read)
@@ -70,6 +76,11 @@ public override int Read(byte[] buffer, int offset, int count)
         /// <inheritdoc/>
         public override int Read(Span<byte> buffer)
         {
+            if (this.disposed)
+            {
+                throw new ObjectDisposedException(nameof(MemoryMappedStream));
+            }
+
             int read = (int)Math.Min(buffer.Length, this.length - this.position);
 
             new Span<byte>(this.ptr + this.position, read)
@@ -83,6 +94,11 @@ public override int Read(Span<byte> buffer)
         /// <inheritdoc/>
         public override long Seek(long offset, SeekOrigin origin)
         {
+            if (this.disposed)
+            {
+                throw new ObjectDisposedException(nameof(MemoryMappedStream));
+            }
+
             long newPosition = this.position;
 
             switch (origin)
@@ -124,5 +140,17 @@ public override void Write(byte[] buffer, int offset, int count)
         {
             throw new NotSupportedException();
         }
+
+        /// <inheritdoc/>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                this.accessor.SafeMemoryMappedViewHandle.ReleasePointer();
+                this.disposed = true;
+            }
+
+            base.Dispose(disposing);
+        }
     }
 }