StorageUtils: Add generation-aware rehashing ID file map

Such a file could be used to store mappings of digests from CAS or
Git cache to digests of different hash type that represent same
content.

1 files changed, 15 insertions, 0 deletions

diff --git a/src/buildtool/storage/fs_utils.hpp b/src/buildtool/storage/fs_utils.hpp
index 7482457b..25392b91 100644
--- a/src/buildtool/storage/fs_utils.hpp
+++ b/src/buildtool/storage/fs_utils.hpp
@@ -20,6 +20,7 @@
 #include <string>
 
 #include "src/buildtool/common/user_structs.hpp"
+#include "src/buildtool/crypto/hash_function.hpp"
 #include "src/buildtool/file_system/symlinks_map/pragma_special.hpp"
 #include "src/buildtool/storage/config.hpp"
 #include "src/buildtool/storage/storage.hpp"
@@ -73,6 +74,20 @@ namespace StorageUtils {
                                          std::size_t generation = 0) noexcept
     -> std::filesystem::path;
 
+/// \brief Get the path to the file storing the corresponding artifact hashed by
+/// a different hash function.
+/// \param storage_config  Storage under which the file is to be found.
+/// \param target_hash_type  Hash type to identify mapping target.
+/// \param hash  Hash to identify mapping source.
+/// \param from_git  Flag to distinguish further mapping source (CAS / GitCAS)
+/// \param generation  Further specificity in location of the file.
+[[nodiscard]] auto GetRehashIDFile(StorageConfig const& storage_config,
+                                   HashFunction::Type target_hash_type,
+                                   std::string const& hash,
+                                   bool from_git,
+                                   std::size_t generation = 0) noexcept
+    -> std::filesystem::path;
+
 /// \brief Write a tree id to file. The parent folder of the file must exist!
 [[nodiscard]] auto WriteTreeIDFile(std::filesystem::path const& tree_id_file,
                                    std::string const& tree_id) noexcept -> bool;