Added MappingFileSystemAdapter and adjusted some more stuff in the VFS module.

source/mijin/virtual_filesystem/relative.hpp

@@ -38,7 +38,6 @@ public:
     RelativeFileSystemAdapter& operator=(const RelativeFileSystemAdapter&) = default;
     RelativeFileSystemAdapter& operator=(RelativeFileSystemAdapter&&) MIJIN_NOEXCEPT = default;
 
-    std::vector<fs::path> getRoots() override;
     fs::path getHomeFolder() override;
     std::vector<FileInfo> listFiles(const fs::path& folder) override;
     FileInfo getFileInfo(const fs::path& file) override;
@@ -52,12 +51,6 @@ private:
 // public functions
 //
 
-template<typename TWrapped>
-std::vector<fs::path> RelativeFileSystemAdapter<TWrapped>::getRoots()
-{
-    return { root_ };
-}
-
 template<typename TWrapped>
 fs::path RelativeFileSystemAdapter<TWrapped>::getHomeFolder()
 {
@@ -106,6 +99,39 @@ fs::path RelativeFileSystemAdapter<TWrapped>::appendPath(const fs::path& other)
     }
     return combinedPath;
 }
+
+namespace vfs_pipe
+{
+template<typename TBase>
+struct RelativeBuilder : Builder<RelativeBuilder<TBase>, RelativeFileSystemAdapter<typename TBase::adapter_t>>
+{
+    fs::path root;
+    TBase base;
+
+    std::unique_ptr<RelativeFileSystemAdapter<typename TBase::adapter_t>> build()
+    {
+        return std::make_unique<RelativeFileSystemAdapter<typename TBase::adapter_t>>(root, std::move(*base.build()));
+    }
+};
+
+struct RelativeOptions
+{
+    fs::path root;
+};
+
+[[nodiscard]]
+inline RelativeOptions relative_to(fs::path root) noexcept
+{
+    return {.root = std::move(root) };
+}
+
+template<typename TBase>
+[[nodiscard]]
+RelativeBuilder<TBase> operator|(TBase other, RelativeOptions options) noexcept
+{
+    return {.root = std::move(options.root), .base = std::move(other) };
+}
+}
 } // namespace mijin
 
 #endif // !defined(MIJIN_VIRTUAL_FILESYSTEM_RELATIVE_HPP_INCLUDED)