Binary patching and FOMOD Presets

Directory.Packages.props

@@ -4,6 +4,7 @@
     <PackageVersion Include="Avalonia.Labs.Panels" Version="11.1.0" />
     <PackageVersion Include="Avalonia.Skia" Version="11.1.0" />
     <PackageVersion Include="AvaloniaEdit.TextMate" Version="11.1.0" />
+    <PackageVersion Include="BsDiff" Version="1.1.0" />
     <PackageVersion Include="LinqGen" Version="0.3.1" />
     <PackageVersion Include="Microsoft.Extensions.Http.Resilience" Version="8.9.1" />
     <PackageVersion Include="Microsoft.Extensions.Options" Version="8.0.2" />

benchmarks/NexusMods.Benchmarks/Benchmarks/Loadouts/Harness/DummyFileStore.cs

@@ -36,6 +36,11 @@ public Task<Stream> GetFileStream(Hash hash, CancellationToken token = default)
         return null!;
     }
 
+    public Task<byte[]> Load(Hash hash, CancellationToken token = default)
+    {
+        return Task.FromResult(Array.Empty<byte>());
+    }
+
     public HashSet<ulong> GetFileHashes()
     {
         return [];

src/Abstractions/NexusMods.Abstractions.Collections/Json/Choices.cs

@@ -1,4 +1,5 @@
 using System.Text.Json.Serialization;
+using NexusMods.Games.FOMOD;
 
 namespace NexusMods.Abstractions.Collections.Json;
 
@@ -7,4 +8,7 @@ public class Choices
     [JsonPropertyName("type")]
     [JsonConverter(typeof(JsonStringEnumConverter))]
     public required ChoicesType Type { get; init; }
+
+    [JsonPropertyName("options")]
+    public FomodOption[] Options { get; init; } = [];
 }

src/Abstractions/NexusMods.Abstractions.Collections/Json/Mod.cs

@@ -1,5 +1,6 @@
 using System.Text.Json.Serialization;
 using NexusMods.Abstractions.Games.DTO;
+using NexusMods.Paths;
 using NexusMods.Abstractions.NexusWebApi.Types.V2;
 
 namespace NexusMods.Abstractions.Collections.Json;
@@ -32,4 +33,12 @@ public class Mod
 
     [JsonPropertyName("choices")]
     public Choices? Choices { get; init; }
+
+    /// <summary>
+    /// Patches for files found in the mod, the string is a path to the file inside the mod's downloaded archive
+    /// and the PatchHash is the CRC32 hash of the file before it's patched. The files patched in this way may
+    /// be installed later via MD5 hash. If the file appears in the Hashes array.
+    /// </summary>
+    [JsonPropertyName("patches")]
+    public Dictionary<string, PatchHash> Patches { get; init; } = new();
 }

src/Abstractions/NexusMods.Abstractions.Collections/Json/PatchHash.cs

@@ -0,0 +1,26 @@
+using System.Globalization;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+using TransparentValueObjects;
+
+namespace NexusMods.Abstractions.Collections.Json;
+
+[JsonConverter(typeof(PatchHashJsonConverter))]
+[ValueObject<uint>]
+public readonly partial struct PatchHash
+{
+
+}
+
+public class PatchHashJsonConverter : JsonConverter<PatchHash>
+{
+    public override PatchHash Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        return PatchHash.From(uint.Parse(reader.GetString()!, NumberStyles.HexNumber));
+    }
+
+    public override void Write(Utf8JsonWriter writer, PatchHash value, JsonSerializerOptions options)
+    {
+        writer.WriteStringValue(value.Value.ToString("X"));
+    }
+}

src/Abstractions/NexusMods.Abstractions.Collections/NexusMods.Abstractions.Collections.csproj

@@ -3,11 +3,13 @@
     <Import Project="$([MSBuild]::GetPathOfFileAbove('NuGet.Build.props', '$(MSBuildThisFileDirectory)../'))" />
 
     <ItemGroup>
+        <PackageReference Include="BsDiff" />
         <PackageReference Include="NexusMods.MnemonicDB.SourceGenerator" PrivateAssets="all" OutputItemType="Analyzer" ReferenceOutputAssembly="false" />
         <PackageReference Include="TransparentValueObjects" PrivateAssets="all" OutputItemType="Analyzer" ReferenceOutputAssembly="false"/>
     </ItemGroup>
 
     <ItemGroup>
+      <ProjectReference Include="..\..\Games\NexusMods.Games.FOMOD\NexusMods.Games.FOMOD.csproj" />
       <ProjectReference Include="..\NexusMods.Abstractions.Loadouts\NexusMods.Abstractions.Loadouts.csproj" />
       <ProjectReference Include="..\NexusMods.Abstractions.NexusModsLibrary\NexusMods.Abstractions.NexusModsLibrary.csproj" />
     </ItemGroup>

src/Abstractions/NexusMods.Abstractions.Collections/Types/HashMapping.cs

@@ -0,0 +1,20 @@
+using NexusMods.Hashing.xxHash64;
+using NexusMods.Paths;
+
+namespace NexusMods.Abstractions.Collections.Types;
+
+/// <summary>
+/// Metadata about a mapping from a MD5 hash to a xxHash64 hash and the size of the file.
+/// </summary>
+public struct HashMapping
+{
+    /// <summary>
+    /// The xxHash64 hash of the file.
+    /// </summary>
+    public required Hash Hash { get; init; }
+
+    /// <summary>
+    /// The size of the file.
+    /// </summary>
+    public required Size Size { get; init; }
+}

src/Abstractions/NexusMods.Abstractions.IO/IFileStore.cs

@@ -1,4 +1,5 @@
-using NexusMods.Hashing.xxHash64;
+using System.Buffers;
+using NexusMods.Hashing.xxHash64;
 using NexusMods.Paths;
 
 namespace NexusMods.Abstractions.IO;
@@ -36,7 +37,7 @@
     /// and manually check for duplicates with <see cref="HaveFile"/> API when constructing
     /// the <paramref name="backups"/> collection.
     ///
     /// The <see cref="BackupFiles"/> itself is thread safe, but duplicates may be made
     /// if called from duplicate threads at once. This can prevent with taking a lock
     /// via <see cref="Lock"/> (and `using` statement). That said, the probability of duplicates
     /// being made without a lock is so low that it is generally recommended not to lock
@@ -75,6 +76,11 @@
     /// <returns></returns>
     Task<Stream> GetFileStream(Hash hash, CancellationToken token = default);
 
+    /// <summary>
+    /// Load the given file into memory, 
+    /// </summary>
+    Task<byte[]> Load(Hash hash, CancellationToken token = default);
+
     /// <summary>
     /// Retrieves hashes of all files associated with this FileStore.
     /// </summary>

src/Abstractions/NexusMods.Abstractions.MnemonicDB.Analyzers/NexusMods.Abstractions.MnemonicDB.Analyzers.csproj

@@ -5,5 +5,9 @@
     <ItemGroup>
       <PackageReference Include="NexusMods.MnemonicDB.Abstractions" />
     </ItemGroup>
+
+    <ItemGroup>
+      <PackageVersion Update="NexusMods.MnemonicDB.Abstractions" Version="0.9.86" />
+    </ItemGroup>
 
 </Project>

src/Games/NexusMods.Games.FOMOD/CoreDelegates/InstallerDelegates.cs

@@ -14,7 +14,7 @@ public sealed class InstallerDelegates : ICoreDelegates
     public IPluginDelegates plugin { get; }
 
     public IUIDelegates ui => UiDelegates;
-    public readonly UiDelegates UiDelegates;
+    public UiDelegates UiDelegates;
 
     public InstallerDelegates(
         ILoggerFactory loggerFactory,

src/Games/NexusMods.Games.FOMOD/CoreDelegates/PresetGuidedInstaller.cs

@@ -0,0 +1,50 @@
+using System.Diagnostics;
+using NexusMods.Abstractions.Activities;
+using NexusMods.Abstractions.GuidedInstallers;
+
+namespace NexusMods.Games.FOMOD.CoreDelegates;
+
+/// <summary>
+/// A IGuidedInstaller implementation that uses a preset list of steps to make the same choices
+/// a user previously made for specific steps.
+/// </summary>
+public class PresetGuidedInstaller : IGuidedInstaller
+{
+    private readonly FomodOption[] _steps;
+    private int _currentStep = 0;
+
+    public PresetGuidedInstaller(FomodOption[] steps)
+    {
+        _steps = steps;
+    }
+
+    public void Dispose()
+    {
+    }
+
+    public void SetupInstaller(string name)
+    {
+    }
+
+    public void CleanupInstaller()
+    {
+    }
+
+    public Task<UserChoice> RequestUserChoice(GuidedInstallationStep installationStep, Percent progress, CancellationToken cancellationToken)
+    {
+        var step = _steps[_currentStep];
+
+        // This looks gross, but it's fairly simple we map through the two trees matching by name, and it's cleaner than 4 nested loops.
+        var choices = 
+                      from srcGroup in step.groups
+                      from installGroup in installationStep.Groups
+                      where installGroup.Name == srcGroup.name
+                      from srcChoice in srcGroup.choices
+                      from installChoice in installGroup.Options
+                      where installChoice.Name == srcChoice.name
+                      select new SelectedOption(installGroup.Id, installChoice.Id);
+
+        _currentStep++;
+        return Task.FromResult(new UserChoice(new UserChoice.GoToNextStep(choices.ToArray())));
+    }
+}

src/Games/NexusMods.Games.FOMOD/FomodAnalyzer.cs

@@ -108,8 +108,16 @@ public async Task DumpToFileSystemAsync(AbsolutePath fomodFolder)
         async Task DumpItem(string relativePath, byte[] data)
         {
             var finalPath = fomodFolder.Combine(relativePath);
-            fs.CreateDirectory(finalPath.Parent);
-            await fs.WriteAllBytesAsync(finalPath, data);
+            try
+            {
+                fs.CreateDirectory(finalPath.Parent);
+                await fs.WriteAllBytesAsync(finalPath, data);
+            }
+            catch (IOException)
+            {
+                // ignored, this is a pathological case where path is broken 
+            }
+
         }
 
         // Dump Xml

src/Games/NexusMods.Games.FOMOD/FomodOptions.cs

@@ -0,0 +1,30 @@
+using System.Text.Json.Serialization;
+
+namespace NexusMods.Games.FOMOD;
+
+public class FomodOption
+{
+    [JsonPropertyName("name")]
+    public string name { get; init; } = string.Empty;
+
+    [JsonPropertyName("groups")]
+    public FomodGroup[] groups { get; init; } = [];
+}
+
+public class FomodGroup
+{
+    [JsonPropertyName("name")]
+    public string name { get; init; } = string.Empty;
+
+    [JsonPropertyName("choices")]
+    public FomodChoice[] choices { get; init; } = [];
+}
+
+public class FomodChoice
+{
+    [JsonPropertyName("name")]
+    public string name { get; init; } = string.Empty;
+
+    [JsonPropertyName("idx")]
+    public int idx { get; init; }
+}

src/Games/NexusMods.Games.FOMOD/FomodXmlInstaller.cs

@@ -59,6 +59,17 @@ public override async ValueTask<InstallerResult> ExecuteAsync(
         ITransaction transaction,
         Loadout.ReadOnly loadout,
         CancellationToken cancellationToken)
+    {
+        return await ExecuteAsync(libraryArchive, loadoutGroup, transaction, loadout, null, cancellationToken);
+    }
+
+    public async ValueTask<InstallerResult> ExecuteAsync(
+        LibraryArchive.ReadOnly libraryArchive,
+        LoadoutItemGroup.New loadoutGroup,
+        ITransaction transaction,
+        Loadout.ReadOnly loadout,
+        FomodOption[]? options,
+        CancellationToken cancellationToken)
     {
         // the component dealing with FOMODs is built to support all kinds of mods, including those without a script.
         // for those cases, stop patterns can be way more complex to deduce the intended installation structure. In our case, where
@@ -83,6 +94,14 @@ public override async ValueTask<InstallerResult> ExecuteAsync(
         var installerDelegates = _delegates as InstallerDelegates;
         if (installerDelegates is not null)
         {
+            if (options is not null)
+            {
+                // NOTE(halgari) The support for passing in presets to the installer is utterly broken. So we're going to
+                // something different: we will create a new guided installer that will simply emit the user choices based on the
+                // provided options.
+                var installer = new PresetGuidedInstaller(options);
+                installerDelegates.UiDelegates = new UiDelegates(ServiceProvider.GetRequiredService<ILogger<UiDelegates>>(), installer);
+            }
             installerDelegates.UiDelegates.CurrentArchiveFiles = tree;
         }
 

src/Games/NexusMods.Games.FOMOD/NexusMods.Games.FOMOD.csproj

@@ -1,5 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
-
+    <!-- NuGet Package Shared Details -->
+    <Import Project="$([MSBuild]::GetPathOfFileAbove('NuGet.Build.props', '$(MSBuildThisFileDirectory)../'))" />
+
     <ItemGroup>
       <ProjectReference Include="..\..\Abstractions\NexusMods.Abstractions.GuidedInstallers\NexusMods.Abstractions.GuidedInstallers.csproj" />
       <ProjectReference Include="..\..\Abstractions\NexusMods.Abstractions.Library.Installers\NexusMods.Abstractions.Library.Installers.csproj" />

src/Games/NexusMods.Games.FOMOD/Services.cs

@@ -15,7 +15,7 @@ public static class Services
     public static IServiceCollection AddFomod(this IServiceCollection services)
     {
         services.AddAttributeCollection(typeof(EmptyDirectory));
-        services.AddSingleton<ICoreDelegates, InstallerDelegates>();
+        services.AddTransient<ICoreDelegates, InstallerDelegates>();
         return services;
     }
 }

src/Networking/NexusMods.Networking.NexusWebApi/GraphQL/CollectionsForGame.graphql

@@ -0,0 +1,17 @@
+
+query CollectionsForGame($gameDomain: String!, $offset: Int!, $count: Int!) 
+{
+    collections(viewAdultContent: true, filter: {gameDomain: {value: $gameDomain, op: EQUALS}}, offset: $offset, count: $count)
+    {
+        totalCount
+        nodesCount
+        nodes {
+            slug
+            name
+            latestPublishedRevision {
+                id
+                revisionNumber
+            }
+        }
+    }
+}