From 9b11cc92ff522d2216af9102a75f54ea657bad0d Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Wed, 19 Jan 2022 11:21:30 +1000
Subject: [PATCH] fs: add scoped_dir container

---
 CMakeLists.txt     |  2 ++
 fs/scoped.cpp      | 51 ++++++++++++++++++++++++++++++++++++++++++++++
 fs/scoped.hpp      | 37 +++++++++++++++++++++++++++++++++
 test/fs/scoped.cpp | 26 +++++++++++++++++++++++
 4 files changed, 116 insertions(+)
 create mode 100644 fs/scoped.cpp
 create mode 100644 fs/scoped.hpp
 create mode 100644 test/fs/scoped.cpp

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 1b039498..e5af6fc5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -344,6 +344,8 @@ list (
     float.hpp
     fourcc.cpp
     fourcc.hpp
+    fs/scoped.cpp
+    fs/scoped.hpp
     fs/tmp_posix.cpp
     fs/tmp.hpp
     functor.hpp
diff --git a/fs/scoped.cpp b/fs/scoped.cpp
new file mode 100644
index 00000000..f4f12c36
--- /dev/null
+++ b/fs/scoped.cpp
@@ -0,0 +1,51 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2022, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include "./scoped.hpp"
+
+#include <cruft/util/debug/assert.hpp>
+
+using cruft::fs::scoped_dir;
+
+
+///////////////////////////////////////////////////////////////////////////////
+scoped_dir::scoped_dir (std::filesystem::path const &_path)
+    : scoped_dir (std::filesystem::path (_path))
+{}
+
+
+//-----------------------------------------------------------------------------
+scoped_dir::scoped_dir (std::filesystem::path &&_path)
+    : m_path (std::move (_path))
+{
+    CHECK (std::filesystem::is_directory (*m_path));
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+scoped_dir::~scoped_dir ()
+{
+    if (m_path)
+        std::filesystem::remove_all (*m_path);
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+std::filesystem::path const &
+scoped_dir::operator* () const &
+{
+    return *m_path;
+}
+
+
+//-----------------------------------------------------------------------------
+std::filesystem::path const*
+scoped_dir::operator-> () const &
+{
+    return &*m_path;
+}
diff --git a/fs/scoped.hpp b/fs/scoped.hpp
new file mode 100644
index 00000000..dcccad2c
--- /dev/null
+++ b/fs/scoped.hpp
@@ -0,0 +1,37 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * Copyright 2022, Danny Robson <danny@nerdcruft.net>
+ */
+
+#include <optional>
+#include <filesystem>
+
+
+///////////////////////////////////////////////////////////////////////////////
+namespace cruft::fs {
+    ///------------------------------------------------------------------------
+    /// Holds the path to a directory that will be deleted (along with all
+    /// contents) when the object goes out of scope.
+    class scoped_dir {
+    public:
+        explicit scoped_dir (std::filesystem::path const&);
+        explicit scoped_dir (std::filesystem::path &&);
+
+        scoped_dir (scoped_dir const&) = delete;
+        scoped_dir& operator= (scoped_dir const&) = delete;
+
+        scoped_dir (scoped_dir&&) noexcept = default;
+        scoped_dir& operator= (scoped_dir&&) noexcept = default;
+
+        ~scoped_dir ();
+
+        std::filesystem::path const& operator*  () const&;
+        std::filesystem::path const* operator-> () const&;
+
+    private:
+        std::optional<std::filesystem::path> m_path;
+    };
+}
\ No newline at end of file
diff --git a/test/fs/scoped.cpp b/test/fs/scoped.cpp
new file mode 100644
index 00000000..35f6a16c
--- /dev/null
+++ b/test/fs/scoped.cpp
@@ -0,0 +1,26 @@
+#include <cruft/util/tap.hpp>
+#include <cruft/util/fs/scoped.hpp>
+#include <cruft/util/fs/tmp.hpp>
+
+
+int
+main (int, char**)
+{
+    cruft::TAP::logger tap;
+
+    {
+        bool success = true;
+        auto const path = cruft::fs::mktmpdir ();
+
+        {
+            cruft::fs::scoped_dir dir (path);
+            success = success && std::filesystem::is_directory (path);
+        }
+
+        success = success && !exists(path);
+
+        tap.expect (success, "scoped_dir removes directory after scope");
+    }
+
+    return tap.status ();
+}
\ No newline at end of file