Storage: Reworked storage and garbage collection

The improved GC implementation uses refactored storage
classes instead of directly accessing "unknown" file paths.
The required storage class refactoring is quite substantial
and outlined in the following paragraphs.

The module `buildtool/file_system` was extended by:

- `ObjectCAS`: a plain CAS implementation for
  reading/writing blobs and computing digests for a given
  `ObjectType`. Depending on that type, files written to the
  file system may have different properties (e.g., the x-bit
  set) or the digest may be computed differently (e.g., tree
  digests in non-compatible mode).

A new module `buildtool/storage` was introduced containing:

- `LocalCAS`: provides a common interface for the "logical
  CAS", which internally combines three `ObjectCAS`s, one
  for each `ObjectType` (file, executable, tree).

- `LocalAC`: implements the action cache, which needs the
  `LocalCAS` for storing cache values.

- `TargetCache`: implements the high-level target cache,
  which also needs the `LocalCAS` for storing cache values.

- `LocalStorage`: combines the storage classes `LocalCAS`,
  `LocalAC`, and `TargetCache`. Those are initialized with
  settings from `StorageConfig`, such as the build root base
  path or number of generations for the garbage collector.
  `LocalStorage` is templated with a Boolean parameter
  `kDoGlobalUplink`, which indicates that, on every
  read/write access, the garbage collector should be used
  for uplinking across all generations (global).

- `GarbageCollector`: responsible for garbage collection and
  the global uplinking across all generations. To do so, it
  employs instances of `LocalStorage` with `kDoGlobalUplink`
  set to false, in order to avoid endless recursion. The
  actual (local) uplinking within two single generations is
  performed by the corresponding storage class (e.g.,
  `TargetCache` implements uplinking of target cache entries
  between two target cache generations etc.). Thereby, the
  actual knowledge how data should be uplinked is
  implemented by the instance that is responsible for
  creating the data in the first place.

1 files changed, 12 insertions, 12 deletions

diff --git a/src/other_tools/just_mr/utils.cpp b/src/other_tools/just_mr/utils.cpp
index 24511742..ca891875 100644
--- a/src/other_tools/just_mr/utils.cpp
+++ b/src/other_tools/just_mr/utils.cpp
@@ -14,14 +14,14 @@
 
 #include "src/other_tools/just_mr/utils.hpp"
 
-#include "src/buildtool/execution_api/local/local_cas.hpp"
 #include "src/buildtool/file_system/file_storage.hpp"
+#include "src/buildtool/storage/storage.hpp"
 #include "src/utils/cpp/path.hpp"
 
 namespace JustMR::Utils {
 
 auto GetGitCacheRoot() noexcept -> std::filesystem::path {
-    return LocalExecutionConfig::BuildRoot() / "git";
+    return StorageConfig::BuildRoot() / "git";
 }
 
 auto GetGitRoot(JustMR::PathsPtr const& just_mr_paths,
@@ -42,20 +42,19 @@ auto GetGitRoot(JustMR::PathsPtr const& just_mr_paths,
 
 auto CreateTypedTmpDir(std::string const& type) noexcept -> TmpDirPtr {
     // try to create parent dir
-    auto parent_path =
-        LocalExecutionConfig::BuildRoot() / "tmp-workspaces" / type;
+    auto parent_path = StorageConfig::BuildRoot() / "tmp-workspaces" / type;
     return TmpDir::Create(parent_path);
 }
 
 auto GetArchiveTreeIDFile(std::string const& repo_type,
                           std::string const& content) noexcept
     -> std::filesystem::path {
-    return LocalExecutionConfig::BuildRoot() / "tree-map" / repo_type / content;
+    return StorageConfig::BuildRoot() / "tree-map" / repo_type / content;
 }
 
 auto GetDistdirTreeIDFile(std::string const& content) noexcept
     -> std::filesystem::path {
-    return LocalExecutionConfig::BuildRoot() / "distfiles-tree-map" / content;
+    return StorageConfig::BuildRoot() / "distfiles-tree-map" / content;
 }
 
 auto WriteTreeIDFile(std::filesystem::path const& tree_id_file,
@@ -79,23 +78,24 @@ auto WriteTreeIDFile(std::filesystem::path const& tree_id_file,
 auto AddToCAS(std::string const& data) noexcept
     -> std::optional<std::filesystem::path> {
     // get file CAS instance
-    auto const& casf = LocalCAS<ObjectType::File>::Instance();
-    // write to casf
-    auto digest = casf.StoreBlobFromBytes(data);
+    auto const& cas = Storage::Instance().CAS();
+    // write to cas
+    auto digest = cas.StoreBlob(data);
     if (digest) {
-        return casf.BlobPath(*digest);
+        return cas.BlobPath(*digest, /*is_executable=*/false);
     }
     return std::nullopt;
 }
 
 void AddDistfileToCAS(std::filesystem::path const& distfile,
                       JustMR::PathsPtr const& just_mr_paths) noexcept {
-    auto const& casf = LocalCAS<ObjectType::File>::Instance();
+    auto const& cas = Storage::Instance().CAS();
     for (auto const& dirpath : just_mr_paths->distdirs) {
         auto candidate = dirpath / distfile;
         if (FileSystemManager::Exists(candidate)) {
             // try to add to CAS
-            [[maybe_unused]] auto digest = casf.StoreBlobFromFile(candidate);
+            [[maybe_unused]] auto digest =
+                cas.StoreBlob(candidate, /*is_executable=*/false);
         }
     }
 }