Nullable enabled for DiscUtils.Core

Author: LTRData

Library/DiscUtils.Core/ApplePartitionMap/PartitionMapEntry.cs

@@ -30,27 +30,27 @@ namespace DiscUtils.ApplePartitionMap;
 internal sealed class PartitionMapEntry : PartitionInfo, IByteArraySerializable
 {
     private readonly Stream _diskStream;
-    private readonly PartitionMap _map;
+    private readonly PartitionMap? _map;
 
     public uint BootBlock;
     public uint BootBytes;
     public uint Flags;
     public uint LogicalBlocks;
     public uint LogicalBlockStart;
     public uint MapEntries;
-    public string Name;
+    public string Name = null!;
     public uint PhysicalBlocks;
     public uint PhysicalBlockStart;
     public ushort Signature;
-    public string Type;
+    public string Type = null!;
 
-    public PartitionMapEntry(Stream diskStream, PartitionMap map)
+    public PartitionMapEntry(Stream diskStream, PartitionMap? map)
     {
         _diskStream = diskStream;
         _map = map;
     }
 
-    public override PartitionTable Table => _map;
+    public override PartitionTable? Table => _map;
 
     public override byte BiosType => 0xAF;
 

Library/DiscUtils.Core/ApplePartitionMap/PartitionMapFactory.cs

@@ -55,7 +55,7 @@ public override bool DetectIsPartitioned(Stream s)
         return initialPart.Signature == 0x504d;
     }
 
-    public override PartitionTable DetectPartitionTable(VirtualDisk disk)
+    public override PartitionTable? DetectPartitionTable(VirtualDisk disk)
     {
         if (!DetectIsPartitioned(disk.Content))
         {

Library/DiscUtils.Core/Archives/TarFile.cs

@@ -25,6 +25,7 @@
 using System;
 using System.Buffers;
 using System.Collections.Generic;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Runtime.CompilerServices;
 using System.Threading;
@@ -53,7 +54,7 @@ public TarFile(Stream fileStream)
 
         Span<byte> hdrBuf = stackalloc byte[512];
 
-        string long_path = null;
+        string? long_path = null;
 
         for (;;)
         {                
@@ -109,7 +110,7 @@ public TarFile(Stream fileStream)
     /// <param name="path">The path to the file within the archive.</param>
     /// <param name="stream">A stream containing the file contents, or null.</param>
     /// <returns><c>true</c> if the file could be opened, else <c>false</c>.</returns>
-    public bool TryOpenFile(string path, out Stream stream)
+    public bool TryOpenFile(string path, [NotNullWhen(true)] out Stream? stream)
     {
         if (_files.TryGetValue(path, out var file))
         {
@@ -198,8 +199,8 @@ public static IEnumerable<TarFileData> EnumerateFiles(Stream archive)
     {
         var hdrBuf = StreamUtilities.GetUninitializedArray<byte>(512);
 
-        string long_path = null;
-        string long_link_path = null;
+        string? long_path = null;
+        string? long_link_path = null;
 
         for (;;)
         {
@@ -332,8 +333,8 @@ public static async IAsyncEnumerable<TarFileData> EnumerateFilesAsync(Stream arc
     {
         var hdrBuf = StreamUtilities.GetUninitializedArray<byte>(512);
 
-        string long_path = null;
-        string long_link_path = null;
+        string? long_path = null;
+        string? long_link_path = null;
 
         for (; ; )
         {

Library/DiscUtils.Core/Archives/TarFileData.cs

@@ -6,19 +6,19 @@ public sealed class TarFileData
 {
     public TarHeader Header { get; }
 
-    private Stream _source;
+    private Stream? _source;
 
     public string Name => Header.FileName;
 
     public long Length => Header.FileLength;
 
-    public TarFileData(TarHeader header, Stream source)
+    public TarFileData(TarHeader header, Stream? source)
     {
         Header = header;
         _source = source;
     }
 
-    public Stream GetStream() => _source;
+    public Stream? GetStream() => _source;
 
     public override string ToString() => Name;
 }

Library/DiscUtils.Core/Archives/TarHeader.cs

@@ -37,20 +37,16 @@ public sealed class TarHeader
     public DateTimeOffset ModificationTime { get; }
     public int CheckSum { get; }
     public TarFileType FileType { get; }
-    public string LinkName { get; internal set; }
-    public string Magic { get; }
+    public string? LinkName { get; internal set; }
+    public string? Magic { get; }
     public int Version { get; }
-    public string OwnerName { get; }
-    public string GroupName { get; }
+    public string? OwnerName { get; }
+    public string? GroupName { get; }
     public int DevMajor { get; }
     public int DevMinor { get; }
     public DateTimeOffset LastAccessTime { get; }
     public DateTimeOffset CreationTime { get; }
 
-    public TarHeader()
-    {
-    }
-
     public TarHeader(string fileName, long fileLength, UnixFilePermissions fileMode, int ownerId, int groupId, DateTime modificationTime)
     {
         FileName = fileName;

Library/DiscUtils.Core/ChsAddress.cs

@@ -72,7 +72,7 @@ public ChsAddress(int cylinder, int head, int sector)
     public bool Equals(ChsAddress other)
         => Cylinder == other.Cylinder && Head == other.Head && Sector == other.Sector;
 
-    public override bool Equals(object obj)
+    public override bool Equals(object? obj)
         => obj is ChsAddress other && Equals(other);
 
     public static bool operator ==(ChsAddress a, ChsAddress b) => a.Equals(b);

Library/DiscUtils.Core/Compression/BZip2CombinedHuffmanTrees.cs

@@ -25,6 +25,7 @@
 //
 
 using DiscUtils.Streams;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 
 namespace DiscUtils.Compression;
@@ -35,7 +36,7 @@ namespace DiscUtils.Compression;
 /// </summary>
 internal class BZip2CombinedHuffmanTrees
 {
-    private HuffmanTree _activeTree;
+    private HuffmanTree? _activeTree;
     private readonly BitStream _bitstream;
     private int _nextSelector;
     private byte[] _selectors;
@@ -51,7 +52,7 @@ public BZip2CombinedHuffmanTrees(BitStream bitstream, int maxSymbols)
 
     public uint NextSymbol()
     {
-        if (_symbolsToNextSelector == 0)
+        if (_symbolsToNextSelector == 0 || _activeTree is null)
         {
             _symbolsToNextSelector = 50;
             _activeTree = _trees[_selectors[_nextSelector]];
@@ -63,6 +64,7 @@ public uint NextSymbol()
         return _activeTree.NextSymbol(_bitstream);
     }
 
+    [MemberNotNull(nameof(_selectors), nameof(_trees))]
     private void Initialize(int maxSymbols)
     {
         var numTrees = (int)_bitstream.Read(3);

Library/DiscUtils.Core/Compression/BZip2DecoderStream.cs

@@ -25,6 +25,7 @@
 //
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -44,7 +45,7 @@ public sealed class BZip2DecoderStream : ReadOnlyCompatibilityStream
     private readonly byte[] _blockBuffer;
     private uint _blockCrc;
     private readonly BZip2BlockDecoder _blockDecoder;
-    private Crc32 _calcBlockCrc;
+    private Crc32? _calcBlockCrc;
     private uint _calcCompoundCrc;
     private uint _compoundCrc;
     private Stream _compressedStream;
@@ -173,7 +174,7 @@ public override int Read(Span<byte> buffer)
             numRead = _rleStream.Read(buffer);
         }
 
-        _calcBlockCrc.Process(buffer.Slice(0, numRead));
+        _calcBlockCrc?.Process(buffer.Slice(0, numRead));
 
         // Pre-read next block, so a client that knows the decompressed length will still
         // have the overall CRC calculated.
@@ -241,7 +242,7 @@ public override async ValueTask<int> ReadAsync(Memory<byte> buffer, Cancellation
             numRead = await _rleStream.ReadAsync(buffer, cancellationToken).ConfigureAwait(false);
         }
 
-        _calcBlockCrc.Process(buffer.Span.Slice(0, numRead));
+        _calcBlockCrc?.Process(buffer.Span.Slice(0, numRead));
 
         // Pre-read next block, so a client that knows the decompressed length will still
         // have the overall CRC calculated.
@@ -299,12 +300,12 @@ protected override void Dispose(bool disposing)
                     _compressedStream.Dispose();
                 }
 
-                _compressedStream = null;
+                _compressedStream = null!;
 
                 if (_rleStream != null)
                 {
                     _rleStream.Dispose();
-                    _rleStream = null;
+                    _rleStream = null!;
                 }
             }
         }

Library/DiscUtils.Core/Compression/BZip2RleStream.cs

@@ -26,6 +26,7 @@
 
 using DiscUtils.Streams.Compatibility;
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -34,7 +35,7 @@ namespace DiscUtils.Compression;
 
 internal class BZip2RleStream : ReadOnlyCompatibilityStream
 {
-    private byte[] _blockBuffer;
+    private byte[]? _blockBuffer;
     private int _blockOffset;
     private int _blockRemaining;
     private byte _lastByte;
@@ -57,6 +58,7 @@ public override long Position
         set => throw new NotSupportedException();
     }
 
+    [MemberNotNull(nameof(_blockBuffer))]
     public void Reset(byte[] buffer, int offset, int count)
     {
         _position = 0;
@@ -79,6 +81,11 @@ public override int Read(byte[] buffer, int offset, int count)
 
     public override int Read(Span<byte> buffer)
     {
+        if (_blockBuffer == null)
+        {
+            throw new InvalidOperationException("Stream not initialized");
+        }
+
         var numRead = 0;
 
         while (numRead < buffer.Length && _runBytesOutstanding > 0)

Library/DiscUtils.Core/Compression/LzxStream.cs

@@ -21,6 +21,7 @@
 //
 
 using System;
+using System.Diagnostics.CodeAnalysis;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
@@ -39,17 +40,17 @@ internal class LzxStream : ReadOnlyCompatibilityStream
 {
     private static readonly uint[] _positionSlots;
     private static readonly uint[] _extraBits;
-    private HuffmanTree _alignedOffsetTree;
+    private HuffmanTree? _alignedOffsetTree;
 
     private readonly LzxBitStream _bitStream;
 
     private byte[] _buffer;
     private int _bufferCount;
     private readonly int _fileSize;
-    private HuffmanTree _lengthTree;
+    private HuffmanTree? _lengthTree;
 
     // Block state
-    private HuffmanTree _mainTree;
+    private HuffmanTree? _mainTree;
     private readonly int _numPositionSlots;
 
     private long _position;
@@ -162,7 +163,6 @@ private void ReadBlocks()
     {
         var blockType = (BlockType)_bitStream.Read(3);
 
-        _buffer = new byte[32768];
         _bufferCount = 0;
 
         while (blockType != BlockType.None)
@@ -240,6 +240,7 @@ private void DecodeUncompressedBlock(int blockSize)
         }
     }
 
+    [MemberNotNull(nameof(_mainTree), nameof(_lengthTree))]
     private void DecodeCompressedBlock(BlockType blockType, int blockSize)
     {
         if (blockType == BlockType.AlignedOffset)
@@ -296,7 +297,7 @@ private void DecodeCompressedBlock(BlockType blockType, int blockSize)
                         if (extra >= 3)
                         {
                             verbatimBits = _bitStream.Read(extra - 3) << 3;
-                            alignedBits = _alignedOffsetTree.NextSymbol(_bitStream);
+                            alignedBits = _alignedOffsetTree!.NextSymbol(_bitStream);
                         }
                         else if (extra > 0)
                         {
@@ -331,6 +332,7 @@ private void DecodeCompressedBlock(BlockType blockType, int blockSize)
         }
     }
 
+    [MemberNotNull(nameof(_mainTree))]
     private void ReadMainTree()
     {
         uint[] lengths;
@@ -352,6 +354,7 @@ private void ReadMainTree()
         _mainTree = new HuffmanTree(lengths);
     }
 
+    [MemberNotNull(nameof(_lengthTree))]
     private void ReadLengthTree()
     {
         var preTree = ReadFixedHuffmanTree(20, 4);
@@ -369,7 +372,7 @@ private HuffmanTree ReadFixedHuffmanTree(int count, int bits)
         return new HuffmanTree(treeLengths);
     }
 
-    private HuffmanTree ReadDynamicHuffmanTree(int count, HuffmanTree preTree, HuffmanTree oldTree)
+    private HuffmanTree ReadDynamicHuffmanTree(int count, HuffmanTree preTree, HuffmanTree? oldTree)
     {
         uint[] lengths;