Add VFS

pkNX.Containers/VFS/FileSystems/Archives/ZipArchiveFileSystem.cs

@@ -0,0 +1,92 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.IO.Compression;
+
+namespace pkNX.Containers.VFS;
+
+public class ZipArchiveFileSystem : IFileSystem
+{
+    public ZipArchive ZipArchive { get; private set; }
+
+    public bool IsReadOnly => false;
+
+    public static ZipArchiveFileSystem Open(Stream s)
+    {
+        return new ZipArchiveFileSystem(new ZipArchive(s, ZipArchiveMode.Update, true));
+    }
+
+    public static ZipArchiveFileSystem Create(Stream s)
+    {
+        return new ZipArchiveFileSystem(new ZipArchive(s, ZipArchiveMode.Create, true));
+    }
+
+    private ZipArchiveFileSystem(ZipArchive archive)
+    {
+        ZipArchive = archive;
+    }
+    public void Dispose()
+    {
+        ZipArchive.Dispose();
+    }
+
+    protected IEnumerable<ZipArchiveEntry> GetZipEntries()
+    {
+        return ZipArchive.Entries;
+    }
+    protected FileSystemPath ToPath(ZipArchiveEntry entry)
+    {
+        return FileSystemPath.Parse(FileSystemPath.DirectorySeparator + entry.FullName);
+    }
+    protected string ToEntryPath(FileSystemPath path)
+    {
+        // Remove heading '/' from path.
+        return path.Path.TrimStart(FileSystemPath.DirectorySeparator);
+    }
+
+    protected ZipArchiveEntry? ToEntry(FileSystemPath path)
+    {
+        return ZipArchive.GetEntry(ToEntryPath(path));
+    }
+    public IEnumerable<FileSystemPath> GetEntities(FileSystemPath path)
+    {
+        return GetZipEntries().Select(ToPath).Where(path.IsParentOf)
+            .Select(entryPath => entryPath.ParentPath == path
+               ? entryPath
+               : path.AppendDirectory(entryPath.RemoveParent(path).GetDirectorySegments().First()))
+            .Distinct()
+            .ToList();
+    }
+
+    public bool Exists(FileSystemPath path)
+    {
+        if (path.IsFile)
+            return ToEntry(path) != null;
+        return GetZipEntries()
+            .Select(ToPath)
+            .Any(entryPath => entryPath.IsChildOf(path) || entryPath.Equals(path));
+    }
+
+    public Stream CreateFile(FileSystemPath path)
+    {
+        var zae = ZipArchive.CreateEntry(ToEntryPath(path));
+        return zae.Open();
+    }
+
+    public Stream OpenFile(FileSystemPath path, FileAccess access)
+    {
+        var entry = ZipArchive.GetEntry(ToEntryPath(path));
+        return entry?.Open() ?? Stream.Null;
+    }
+
+    public void CreateDirectory(FileSystemPath path)
+    {
+        ZipArchive.CreateEntry(ToEntryPath(path));
+    }
+
+    public void Delete(FileSystemPath path)
+    {
+        var entry = ZipArchive.GetEntry(ToEntryPath(path));
+        entry?.Delete();
+    }
+}