LocalCAS: Set epoch time for every entry

... and refactor static constant to proper format `kFdLess`.

3 files changed, 15 insertions, 13 deletions

diff --git a/src/buildtool/execution_api/local/file_storage.hpp b/src/buildtool/execution_api/local/file_storage.hpp
index ec7714f6..0af749ad 100644
--- a/src/buildtool/execution_api/local/file_storage.hpp
+++ b/src/buildtool/execution_api/local/file_storage.hpp
@@ -17,8 +17,7 @@ enum class StoreMode {
     LastWins
 };
 
-template <ObjectType kType = ObjectType::File,
-          StoreMode kMode = StoreMode::FirstWins>
+template <ObjectType kType, StoreMode kMode, bool kSetEpochTime>
 class FileStorage {
   public:
     explicit FileStorage(std::filesystem::path storage_root) noexcept
@@ -47,8 +46,8 @@ class FileStorage {
     }
 
   private:
+    static constexpr bool kFdLess{kType == ObjectType::Executable};
     std::filesystem::path const storage_root_{};
-    static constexpr bool fd_less_{kType == ObjectType::Executable};
 
     /// \brief Add file to storage from file path via link or copy and rename.
     /// If a race-condition occurs, the winning thread will be the one
@@ -68,7 +67,8 @@ class FileStorage {
                 // Entry does not exist and we are owner of the file (e.g., file
                 // generated in the execution directory). Try to hard link it
                 // directly or check its existence if it was created by now.
-                return FileSystemManager::CreateFileHardlinkAs<kType>(
+                return FileSystemManager::CreateFileHardlinkAs<kType,
+                                                               kSetEpochTime>(
                            path, file_path) or
                        FileSystemManager::IsFile(file_path);
             };
@@ -124,10 +124,11 @@ class FileStorage {
         // directory), prefer faster creation of hard links instead of a copy.
         // Copy executables without opening any writeable file descriptors in
         // this process to avoid those from being inherited by child processes.
-        return (is_owner and FileSystemManager::CreateFileHardlinkAs<kType>(
-                                 other_path, file_path)) or
-               FileSystemManager::CopyFileAs<kType>(
-                   other_path, file_path, fd_less_);
+        return (is_owner and
+                FileSystemManager::CreateFileHardlinkAs<kType, kSetEpochTime>(
+                    other_path, file_path)) or
+               FileSystemManager::CopyFileAs<kType, kSetEpochTime>(
+                   other_path, file_path, kFdLess);
     }
 
     /// \brief Create file from bytes.
@@ -136,8 +137,8 @@ class FileStorage {
         std::string const& bytes) noexcept -> bool {
         // Write executables without opening any writeable file descriptors in
         // this process to avoid those from being inherited by child processes.
-        return FileSystemManager::WriteFileAs<kType>(
-            bytes, file_path, fd_less_);
+        return FileSystemManager::WriteFileAs<kType, kSetEpochTime>(
+            bytes, file_path, kFdLess);
     }
 
     /// \brief Stage file from source path to target path.
diff --git a/src/buildtool/execution_api/local/local_ac.hpp b/src/buildtool/execution_api/local/local_ac.hpp
index f319940a..f8cc3b7a 100644
--- a/src/buildtool/execution_api/local/local_ac.hpp
+++ b/src/buildtool/execution_api/local/local_ac.hpp
@@ -76,7 +76,8 @@ class LocalAC {
     gsl::not_null<LocalCAS<ObjectType::File>*> cas_;
     std::filesystem::path const cache_root_{
         LocalExecutionConfig::GetCacheDir()};
-    FileStorage<ObjectType::File, kStoreMode> file_store_{cache_root_ / "ac"};
+    FileStorage<ObjectType::File, kStoreMode, /*kSetEpochTime=*/false>
+        file_store_{cache_root_ / "ac"};
 };
 
 #endif  // INCLUDED_SRC_BUILDTOOL_EXECUTION_API_LOCAL_LOCAL_AC_HPP
diff --git a/src/buildtool/execution_api/local/local_cas.hpp b/src/buildtool/execution_api/local/local_cas.hpp
index 470c38b9..f5158662 100644
--- a/src/buildtool/execution_api/local/local_cas.hpp
+++ b/src/buildtool/execution_api/local/local_cas.hpp
@@ -52,8 +52,8 @@ class LocalCAS {
     Logger logger_{std::string{"LocalCAS"} + kSuffix};
     std::filesystem::path const cache_root_{
         LocalExecutionConfig::GetCacheDir()};
-    FileStorage<kType> file_store_{cache_root_ /
-                                   (std::string{"cas"} + kSuffix)};
+    FileStorage<kType, StoreMode::FirstWins, /*kSetEpochTime=*/true>
+        file_store_{cache_root_ / (std::string{"cas"} + kSuffix)};
 
     [[nodiscard]] static auto CreateDigest(std::string const& bytes) noexcept
         -> std::optional<bazel_re::Digest> {