GitCAS: implement method for creation of an empty GitCAS

...and use it in GitRepo to set custom backends.

(cherry-picked 99860b78304817c4d5b27ec4c661b733e30a430a)

1 files changed, 7 insertions, 0 deletions

diff --git a/src/buildtool/file_system/git_cas.hpp b/src/buildtool/file_system/git_cas.hpp
index 78cb6d0c..f358e65b 100644
--- a/src/buildtool/file_system/git_cas.hpp
+++ b/src/buildtool/file_system/git_cas.hpp
@@ -24,6 +24,7 @@
 #include <utility>
 #include <vector>
 
+#include "gsl/gsl"
 #include "src/buildtool/file_system/git_context.hpp"
 #include "src/buildtool/file_system/git_utils.hpp"
 
@@ -36,6 +37,8 @@ class GitCAS {
     [[nodiscard]] static auto Open(
         std::filesystem::path const& repo_path) noexcept -> GitCASPtr;
 
+    [[nodiscard]] static auto CreateEmpty() noexcept -> GitCASPtr;
+
     GitCAS() noexcept;
     ~GitCAS() noexcept = default;
 
@@ -45,6 +48,10 @@ class GitCAS {
     auto operator=(GitCAS const&) = delete;
     auto operator=(GitCAS&& other) = delete;
 
+    [[nodiscard]] auto GetODB() const noexcept -> gsl::not_null<git_odb*> {
+        return odb_.get();
+    }
+
     /// \brief Read object from CAS.
     /// \param id         The object id.
     /// \param is_hex_id  Specify whether `id` is hex string or raw.