feat(mosstank): add VTank-style automation PoC

src/AcDream.App/Plugins/FilePluginStorage.cs

@@ -0,0 +1,86 @@
+using System.Text;
+using AcDream.Plugin.Abstractions;
+
+namespace AcDream.App.Plugins;
+
+/// <summary>Crash-safe filesystem implementation behind scoped plugin keys.</summary>
+internal sealed class FilePluginStorage : IPluginStorage
+{
+    private readonly string _root;
+
+    internal FilePluginStorage(string root)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(root);
+        _root = Path.GetFullPath(root);
+    }
+
+    public bool IsAvailable => true;
+
+    public string? ReadText(string key)
+    {
+        string path = Resolve(key);
+        return File.Exists(path)
+            ? File.ReadAllText(path, Encoding.UTF8)
+            : null;
+    }
+
+    public IReadOnlyList<string> List(string prefix)
+    {
+        string directory = Resolve(prefix);
+        if (!Directory.Exists(directory))
+            return Array.Empty<string>();
+        return Directory.EnumerateFiles(directory, "*", SearchOption.AllDirectories)
+            .Select(path => Path.GetRelativePath(_root, path)
+                .Replace(Path.DirectorySeparatorChar, '/'))
+            .OrderBy(static key => key, StringComparer.OrdinalIgnoreCase)
+            .ToArray();
+    }
+
+    public void WriteText(string key, string content)
+    {
+        ArgumentNullException.ThrowIfNull(content);
+        string path = Resolve(key);
+        string directory = Path.GetDirectoryName(path)!;
+        Directory.CreateDirectory(directory);
+        string temporary = Path.Combine(
+            directory,
+            $".{Path.GetFileName(path)}.{Guid.NewGuid():N}.tmp");
+        try
+        {
+            File.WriteAllText(temporary, content, new UTF8Encoding(false));
+            File.Move(temporary, path, overwrite: true);
+        }
+        finally
+        {
+            if (File.Exists(temporary))
+                File.Delete(temporary);
+        }
+    }
+
+    public bool Delete(string key)
+    {
+        string path = Resolve(key);
+        if (!File.Exists(path))
+            return false;
+        File.Delete(path);
+        return true;
+    }
+
+    private string Resolve(string key)
+    {
+        ArgumentException.ThrowIfNullOrWhiteSpace(key);
+        if (Path.IsPathRooted(key))
+            throw new ArgumentException("Plugin storage keys must be relative.", nameof(key));
+        string path = Path.GetFullPath(Path.Combine(_root, key));
+        string relative = Path.GetRelativePath(_root, path);
+        if (Path.IsPathRooted(relative)
+            || relative.Equals("..", StringComparison.Ordinal)
+            || relative.StartsWith(
+                ".." + Path.DirectorySeparatorChar,
+                StringComparison.Ordinal))
+        {
+            throw new ArgumentException("Plugin storage key escapes its root.", nameof(key));
+        }
+        return path;
+    }
+}