filesystem: Add logic for handling (non-upwards) symlinks

1 files changed, 13 insertions, 0 deletions

diff --git a/src/utils/cpp/path.hpp b/src/utils/cpp/path.hpp
index d872535e..a9fb08e5 100644
--- a/src/utils/cpp/path.hpp
+++ b/src/utils/cpp/path.hpp
@@ -16,6 +16,7 @@
 #define INCLUDED_SRC_UTILS_CPP_PATH_HPP
 
 #include <filesystem>
+#include <sstream>
 
 [[nodiscard]] static inline auto ToNormalPath(std::filesystem::path const& p)
     -> std::filesystem::path {
@@ -29,4 +30,16 @@
     return n;
 }
 
+/// \brief Perform a non-upwards condition check on the given path.
+/// A path is non-upwards if it is relative and it never references any other
+/// path on a higher level in the directory tree than itself.
+[[nodiscard]] static auto PathIsNonUpwards(
+    std::filesystem::path const& path) noexcept -> bool {
+    if (path.is_absolute()) {
+        return false;
+    }
+    // check non-upwards condition
+    return *path.lexically_normal().begin() != "..";
+}
+
 #endif