Added: Extensions for Nx Library And Support for Writing to Memory Mapped Files

.editorconfig

@@ -2,76 +2,35 @@ root = true
 
 [*]
 charset = utf-8
+end_of_line = lf
 insert_final_newline = true
-trim_trailing_whitespace = true
-max_line_length = 120
-
-# Microsoft .NET properties
-csharp_new_line_before_members_in_object_initializers = false
-csharp_preferred_modifier_order = public, private, protected, internal, file, new, static, abstract, virtual, sealed, readonly, override, extern, unsafe, volatile, async, required:suggestion
-csharp_style_prefer_utf8_string_literals = true:suggestion
-csharp_style_var_elsewhere = true:warning
-csharp_style_var_for_built_in_types = true:warning
-csharp_style_var_when_type_is_apparent = true:warning
-dotnet_naming_rule.unity_serialized_field_rule.import_to_resharper = True
-dotnet_naming_rule.unity_serialized_field_rule.resharper_description = Unity serialized field
-dotnet_naming_rule.unity_serialized_field_rule.resharper_guid = 5f0fdb63-c892-4d2c-9324-15c80b22a7ef
-dotnet_naming_rule.unity_serialized_field_rule.severity = warning
-dotnet_naming_rule.unity_serialized_field_rule.style = lower_camel_case_style
-dotnet_naming_rule.unity_serialized_field_rule.symbols = unity_serialized_field_symbols
-dotnet_naming_style.lower_camel_case_style.capitalization = camel_case
-dotnet_naming_symbols.unity_serialized_field_symbols.applicable_accessibilities = *
-dotnet_naming_symbols.unity_serialized_field_symbols.applicable_kinds =
-dotnet_naming_symbols.unity_serialized_field_symbols.resharper_applicable_kinds = unity_serialised_field
-dotnet_naming_symbols.unity_serialized_field_symbols.resharper_required_modifiers = instance
-dotnet_style_parentheses_in_arithmetic_binary_operators = never_if_unnecessary:none
-dotnet_style_parentheses_in_other_binary_operators = always_for_clarity:none
-dotnet_style_parentheses_in_relational_binary_operators = never_if_unnecessary:none
-dotnet_style_predefined_type_for_locals_parameters_members = true:suggestion
-dotnet_style_predefined_type_for_member_access = true:suggestion
-dotnet_style_qualification_for_event = false:warning
-dotnet_style_qualification_for_field = false:warning
-dotnet_style_qualification_for_method = false:warning
-dotnet_style_qualification_for_property = false:warning
-dotnet_style_require_accessibility_modifiers = for_non_interface_members:suggestion
-
-# ReSharper properties
-resharper_apply_auto_detected_rules = false
-resharper_autodetect_indent_settings = true
-resharper_csharp_empty_block_style = together_same_line
-resharper_csharp_stick_comment = false
-resharper_outdent_statement_labels = true
-resharper_show_autodetect_configure_formatting_tip = false
-resharper_use_indent_from_vs = false
-resharper_wrap_lines = true
-
-# ReSharper inspection severities
-resharper_arrange_redundant_parentheses_highlighting = hint
-resharper_arrange_type_member_modifiers_highlighting = hint
-resharper_arrange_type_modifiers_highlighting = hint
-resharper_built_in_type_reference_style_for_member_access_highlighting = hint
-resharper_built_in_type_reference_style_highlighting = hint
-
-[*.cs]
-indent_size = 4
 indent_style = space
-tab_width = 4
-
-# CS4014: Task not awaited
-dotnet_diagnostic.cs4014.severity = error
-
-# CS8509: Missing switch case for named enum value
-dotnet_diagnostic.CS8509.severity = error
-
-# CS824: Missing switch case for unnamed enum value
-dotnet_diagnostic.CS8524.severity = none
+indent_size = 4
 
-# Enums should not have duplicate values
-dotnet_diagnostic.CA1069.severity = error
+[{*.har,*.jsb2,*.jsb3,*.json,*.jsonc,*.postman_collection,*.postman_collection.json,*.postman_environment,*.postman_environment.json,.babelrc,.eslintrc,.prettierrc,.stylelintrc,bowerrc,jest.config}]
+indent_style = space
+indent_size = 2
 
 [{*.yaml,*.yml}]
 indent_style = space
 indent_size = 2
 
-[*.csproj]
+[{*.bash,*.sh,*.zsh}]
+indent_style = space
+indent_size = 2
+
+[*.{appxmanifest,asax,ascx,aspx,axaml,build,c,c++,c++m,cc,ccm,cginc,compute,cp,cpp,cppm,cs,cshtml,cu,cuh,cxx,cxxm,dtd,fs,fsi,fsscript,fsx,fx,fxh,h,hh,hlsl,hlsli,hlslinc,hpp,hxx,inc,inl,ino,ipp,ixx,master,ml,mli,mpp,mq4,mq5,mqh,mxx,nuspec,paml,razor,resw,resx,shader,skin,tpp,usf,ush,uxml,vb,xaml,xamlx,xoml,xsd}]
+indent_style = space
 indent_size = 4
+tab_width = 4
+
+# Verify settings
+[*.{received,verified}.{txt,xml,json}]
+charset = "utf-8-bom"
+end_of_line = lf
+indent_size =
+indent_style =
+insert_final_newline = false
+tab_width =
+trim_trailing_whitespace = false
+

.globalconfig

@@ -0,0 +1,20 @@
+is_global = true
+
+# CS4014: Task not awaited
+dotnet_diagnostic.cs4014.severity = error
+
+# CS8509: Missing switch case for named enum value
+dotnet_diagnostic.CS8509.severity = error
+
+# CS824: Missing switch case for unnamed enum value
+dotnet_diagnostic.CS8524.severity = none
+
+# Enums should not have duplicate values
+dotnet_diagnostic.CA1069.severity = error
+
+# Non-constant fields should not be visible
+dotnet_diagnostic.CA2211.severity = error
+
+# Don't call Enumerable.Cast<T> or Enumerable.OfType<T> with incompatible types
+dotnet_diagnostic.CA2021.severity = error
+

NexusMods.Paths.sln

@@ -32,6 +32,14 @@ Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Paths.TestingHelp
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Paths.Benchmarks", "src\NexusMods.Paths.Benchmarks\NexusMods.Paths.Benchmarks.csproj", "{E86B44A1-D57E-4B0B-8F62-869E1784C49C}"
 EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Extensions", "Extensions", "{1351E5E7-6B95-405D-92CE-D7ECAF67464C}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Paths.Extensions.Nx", "src\Extensions\NexusMods.Paths.Extensions.Nx\NexusMods.Paths.Extensions.Nx.csproj", "{4656B671-8002-461D-8C4C-74A77546C187}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Extensions", "Extensions", "{332D93F6-E1F1-4F51-88D6-B4B364DDBDBC}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "NexusMods.Paths.Extensions.Nx.Tests", "tests\Extensions\NexusMods.Paths.Extensions.Nx.Tests\NexusMods.Paths.Extensions.Nx.Tests.csproj", "{D5012909-9405-4DE0-84E7-354A5EFDF0FC}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -42,6 +50,10 @@ Global
 		{30CBEB4A-E0C0-4B11-A0CF-F97BFACEEF89} = {6ED01F9D-5E12-4EB2-9601-64A2ADC719DE}
 		{FABE9B73-49FF-472C-9013-F52876F25E1D} = {0377EBE6-F147-4233-86AD-32C821B9567E}
 		{E86B44A1-D57E-4B0B-8F62-869E1784C49C} = {0377EBE6-F147-4233-86AD-32C821B9567E}
+		{1351E5E7-6B95-405D-92CE-D7ECAF67464C} = {0377EBE6-F147-4233-86AD-32C821B9567E}
+		{4656B671-8002-461D-8C4C-74A77546C187} = {1351E5E7-6B95-405D-92CE-D7ECAF67464C}
+		{332D93F6-E1F1-4F51-88D6-B4B364DDBDBC} = {6ED01F9D-5E12-4EB2-9601-64A2ADC719DE}
+		{D5012909-9405-4DE0-84E7-354A5EFDF0FC} = {332D93F6-E1F1-4F51-88D6-B4B364DDBDBC}
 	EndGlobalSection
 	GlobalSection(ProjectConfigurationPlatforms) = postSolution
 		{A92DED3D-BC67-4E04-9A06-9A1B302B3070}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
@@ -60,5 +72,13 @@ Global
 		{E86B44A1-D57E-4B0B-8F62-869E1784C49C}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{E86B44A1-D57E-4B0B-8F62-869E1784C49C}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{E86B44A1-D57E-4B0B-8F62-869E1784C49C}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4656B671-8002-461D-8C4C-74A77546C187}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4656B671-8002-461D-8C4C-74A77546C187}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4656B671-8002-461D-8C4C-74A77546C187}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4656B671-8002-461D-8C4C-74A77546C187}.Release|Any CPU.Build.0 = Release|Any CPU
+		{D5012909-9405-4DE0-84E7-354A5EFDF0FC}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{D5012909-9405-4DE0-84E7-354A5EFDF0FC}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{D5012909-9405-4DE0-84E7-354A5EFDF0FC}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{D5012909-9405-4DE0-84E7-354A5EFDF0FC}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 EndGlobal

src/Extensions/NexusMods.Paths.Extensions.Nx/FileProviders/FileData/PathsMemoryMappedFileData.cs

@@ -0,0 +1,60 @@
+using System;
+using NexusMods.Archives.Nx.Interfaces;
+
+namespace NexusMods.Paths.Extensions.Nx.FileProviders.FileData;
+
+/// <summary>
+///     Provides access to data of a Paths memory-mapped file.
+/// </summary>
+public unsafe class PathsMemoryMappedFileData : IFileData
+{
+    private readonly MemoryMappedFileHandle _memoryMappedFileHandle;
+    private readonly bool _disposeHandle;
+    private bool _disposed;
+
+    /// <inheritdoc />
+    public byte* Data { get; }
+
+    /// <inheritdoc />
+    public ulong DataLength { get; }
+
+    /// <summary>
+    ///     Paths memory mapped file data.
+    /// </summary>
+    /// <param name="handle">The handle to use</param>
+    /// <param name="start">The start offset in the file</param>
+    /// <param name="length">The length of the data to map</param>
+    /// <param name="disposeHandle">Disposes the handle on close.</param>
+    public PathsMemoryMappedFileData(MemoryMappedFileHandle handle, ulong start, ulong length, bool disposeHandle = true)
+    {
+        _memoryMappedFileHandle = handle;
+        _disposeHandle = disposeHandle;
+        if (start >= handle.Length)
+        {
+            Data = handle.Pointer;
+            DataLength = 0;
+        }
+        else
+        {
+            Data = handle.Pointer + start;
+            DataLength = Math.Min(length, handle.Length - start);
+        }
+    }
+
+    /// <inheritdoc />
+    ~PathsMemoryMappedFileData() => Dispose();
+
+    /// <inheritdoc />
+    public void Dispose()
+    {
+        if (_disposed)
+            return;
+
+        _disposed = true;
+
+        if (_disposeHandle)
+            _memoryMappedFileHandle.Dispose();
+
+        GC.SuppressFinalize(this);
+    }
+}

src/Extensions/NexusMods.Paths.Extensions.Nx/FileProviders/FromAbsolutePathProvider.cs

@@ -0,0 +1,29 @@
+using NexusMods.Archives.Nx.Interfaces;
+using NexusMods.Paths.Extensions.Nx.FileProviders.FileData;
+using System.IO;
+using System.IO.MemoryMappedFiles;
+
+namespace NexusMods.Paths.Extensions.Nx.FileProviders;
+
+/// <summary>
+///    A provider for creating <see cref="IFileData" /> instances from an absolute path
+/// </summary>
+public class FromAbsolutePathProvider : IFileDataProvider
+{
+    /// <summary>
+    ///     The full path to the file from which the data will be fetched.
+    /// </summary>
+    public required AbsolutePath FilePath { get; init; }
+
+    /// <inheritdoc />
+    public IFileData GetFileData(ulong start, ulong length)
+    {
+        // TODO: This could probably be better, as it's unoptimal for chunked files.
+        // Ideally the file should be opened once in the provider and then calls in GetFileData
+        // could work on slices of the larger MMF.
+        // This however requires a change in Nx itself, which should be done at some point.
+        var fileSystem = FilePath.FileSystem;
+        var handle = fileSystem.CreateMemoryMappedFile(FilePath, FileMode.Open, MemoryMappedFileAccess.Read, 0);
+        return new PathsMemoryMappedFileData(handle, start, length);
+    }
+}

src/Extensions/NexusMods.Paths.Extensions.Nx/FileProviders/OutputAbsolutePathProvider.cs

@@ -0,0 +1,94 @@
+using System;
+using System.IO;
+using System.IO.MemoryMappedFiles;
+using NexusMods.Archives.Nx.FileProviders.FileData;
+using NexusMods.Archives.Nx.Headers.Managed;
+using NexusMods.Archives.Nx.Interfaces;
+using NexusMods.Paths.Extensions.Nx.FileProviders.FileData;
+
+namespace NexusMods.Paths.Extensions.Nx.FileProviders;
+
+/// <summary>
+///     A provider for creating <see cref="IFileData" /> instances which allow
+///     the user to output information to an absolute path.
+/// </summary>
+public class OutputAbsolutePathProvider : IOutputDataProvider
+{
+    /// <inheritdoc />
+    public string RelativePath { get; }
+
+    /// <inheritdoc />
+    public FileEntry Entry { get; }
+
+    /// <summary>
+    ///     Full path to the file.
+    /// </summary>
+    public AbsolutePath FullPath { get; }
+
+    private readonly MemoryMappedFileHandle? _mappedFileHandle;
+    private bool _isDisposed;
+    private readonly bool _isEmpty;
+
+    /// <summary>
+    ///     Initializes outputting a file to an absolute path.
+    /// </summary>
+    /// <param name="fullPath">The absolute path to output the file.</param>
+    /// <param name="relativePath">The relative path of the file (context from the Nx archive).</param>
+    /// <param name="entry">The individual file entry (context from the Nx archive).</param>
+    public OutputAbsolutePathProvider(AbsolutePath fullPath, string relativePath, FileEntry entry)
+    {
+        RelativePath = relativePath;
+        Entry = entry;
+        FullPath = fullPath;
+
+    TryCreate:
+        try
+        {
+            if (entry.DecompressedSize <= 0)
+            {
+                using var _ = FullPath.FileSystem.CreateFile(FullPath);
+                _isEmpty = true;
+                return;
+            }
+
+            // Ensure the directory exists
+            FullPath.FileSystem.CreateDirectory(FullPath.Parent);
+
+            // Delete the file if it exists to ensure we start with an empty file
+            if (FullPath.FileSystem.FileExists(FullPath))
+                FullPath.FileSystem.DeleteFile(FullPath);
+
+            // Create the memory mapped file
+            _mappedFileHandle = FullPath.FileSystem.CreateMemoryMappedFile(FullPath, FileMode.CreateNew, MemoryMappedFileAccess.ReadWrite, entry.DecompressedSize);
+        }
+        catch (DirectoryNotFoundException)
+        {
+            // This is written this way because explicit check is slow.
+            FullPath.FileSystem.CreateDirectory(FullPath.Parent);
+            goto TryCreate;
+        }
+    }
+
+    /// <inheritdoc />
+    public IFileData GetFileData(ulong start, ulong length)
+    {
+        if (_isEmpty)
+            return new ArrayFileData(Array.Empty<byte>(), 0, 0);
+
+        return new PathsMemoryMappedFileData(_mappedFileHandle!.Value, start, length, false);
+    }
+
+    /// <inheritdoc />
+    ~OutputAbsolutePathProvider() => Dispose();
+
+    /// <inheritdoc />
+    public void Dispose()
+    {
+        if (_isDisposed)
+            return;
+
+        _isDisposed = true;
+        _mappedFileHandle?.Dispose();
+        GC.SuppressFinalize(this);
+    }
+}

src/Extensions/NexusMods.Paths.Extensions.Nx/NexusMods.Paths.Extensions.Nx.csproj

@@ -0,0 +1,16 @@
+<Project Sdk="Microsoft.NET.Sdk">
+    <Import Project="$([MSBuild]::GetPathOfFileAbove('NuGet.Build.props', '$(MSBuildThisFileDirectory)../../'))" />
+
+    <PropertyGroup>
+        <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
+    </PropertyGroup>
+
+    <ItemGroup>
+      <PackageReference Include="NexusMods.Archives.Nx" Version="0.5.0" />
+    </ItemGroup>
+
+    <ItemGroup>
+      <ProjectReference Include="..\..\NexusMods.Paths\NexusMods.Paths.csproj" />
+    </ItemGroup>
+
+</Project>

src/NexusMods.Paths/FileSystemAbstraction/BaseFileSystem.cs

@@ -424,9 +424,9 @@ public virtual UnixFileMode GetUnixFileMode(AbsolutePath absolutePath)
     }
 
     /// <inheritdoc/>
-    public MemoryMappedFileHandle CreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access)
+    public MemoryMappedFileHandle CreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access, ulong fileSize)
     {
-        return InternalCreateMemoryMappedFile(GetMappedPath(absPath), mode, access);
+        return InternalCreateMemoryMappedFile(GetMappedPath(absPath), mode, access, fileSize);
     }
 
     #endregion
@@ -470,6 +470,6 @@ public MemoryMappedFileHandle CreateMemoryMappedFile(AbsolutePath absPath, FileM
     protected abstract void InternalMoveFile(AbsolutePath source, AbsolutePath dest, bool overwrite);
 
     /// <inheritdoc cref="IFileSystem.CreateMemoryMappedFile"/>
-    protected abstract MemoryMappedFileHandle InternalCreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access);
+    protected abstract MemoryMappedFileHandle InternalCreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access, ulong fileSize);
     #endregion
 }

src/NexusMods.Paths/FileSystemAbstraction/IFileSystem.cs

@@ -289,5 +289,6 @@ Stream OpenFile(AbsolutePath path,
     /// <param name="absPath">Path of the file to memory map.</param>
     /// <param name="mode">The mode the file is opened with.</param>
     /// <param name="access">What you intend to do with the memory mapped file.</param>
-    MemoryMappedFileHandle CreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access);
+    /// <param name="fileSize">The size of the file, if creating a new file.</param>
+    MemoryMappedFileHandle CreateMemoryMappedFile(AbsolutePath absPath, FileMode mode, MemoryMappedFileAccess access, ulong fileSize);
 }