From 5b41381ac95e4c4dbfba42a58911a767458fa4f5 Mon Sep 17 00:00:00 2001
From: "google-labs-jules[bot]"
 <161369871+google-labs-jules[bot]@users.noreply.github.com>
Date: Thu, 11 Dec 2025 07:40:55 +0000
Subject: [PATCH] feat: add native WebDAV submodule with usability helpers and
 fixes

This commit introduces a new, high-performance, and extensible WebDAV submodule, implemented natively without external dependencies. It also adds a high-level API to simplify common use cases and incorporates numerous fixes based on detailed code reviews.

Features:
- A core WebDAV handler that supports essential methods: PROPFIND, MKCOL, GET, PUT, DELETE, COPY, MOVE, LOCK, and UNLOCK.
- An extensible design using a `FileSystem` interface to decouple the protocol logic from the storage backend.
- Two `FileSystem` implementations:
  - `MemFS`: An in-memory, tree-based filesystem for testing and ephemeral storage.
  - `OSFS`: A secure, OS-based filesystem that interacts with the local disk, including robust path traversal and symlink protection.
- A `LockSystem` interface with an in-memory implementation (`MemLock`) that supports resource locking and includes a graceful shutdown mechanism.
- A high-level API in `webdav/easy.go` (`Serve`, `Register`) to simplify serving local directories.
- RFC 4918 compliance for core operations.
- Performance optimizations, including `sync.Pool` for object reuse and `sync/atomic` for lock-free field access to reduce GC pressure.
- Comprehensive unit tests and a working example application.

The Touka framework's core has been updated to recognize all WebDAV-specific HTTP methods. This implementation addresses numerous points from detailed code reviews, including security vulnerabilities, memory leaks, RFC compliance issues, and path handling bugs.