TreeStructure: Implement cache with uplinking

1 files changed, 62 insertions, 0 deletions

diff --git a/src/buildtool/tree_structure/tree_structure_cache.hpp b/src/buildtool/tree_structure/tree_structure_cache.hpp
new file mode 100644
index 00000000..4d57da7f
--- /dev/null
+++ b/src/buildtool/tree_structure/tree_structure_cache.hpp
@@ -0,0 +1,62 @@
+// Copyright 2024 Huawei Cloud Computing Technology Co., Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_CACHE_HPP
+#define INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_CACHE_HPP
+
+#include <cstddef>
+#include <optional>
+
+#include "gsl/gsl"
+#include "src/buildtool/common/artifact_digest.hpp"
+#include "src/buildtool/file_system/file_storage.hpp"
+#include "src/buildtool/file_system/object_type.hpp"
+#include "src/buildtool/storage/config.hpp"
+
+class TreeStructureCache final {
+  public:
+    explicit TreeStructureCache(
+        gsl::not_null<StorageConfig const*> const& storage_config) noexcept;
+
+    /// \brief Obtain the digest describing the tree structure of a key tree.
+    /// Can trigger deep uplinking of referenced objects (both key and value).
+    [[nodiscard]] auto Get(ArtifactDigest const& key) const noexcept
+        -> std::optional<ArtifactDigest>;
+
+    /// \brief Set coupling between key and value digest signalizing that the
+    /// value digest contains the tree structure of a key digest. Both key and
+    /// value are expected to be in the storage. Can trigger deep uplinking of
+    /// objects (both key and value).
+    /// \return True if the cache contains the key-value coupling. Fails if
+    /// there is the key in the storage, but it refers to another value. Fails
+    /// if key or value aren't present in the storage.
+    [[nodiscard]] auto Set(ArtifactDigest const& key,
+                           ArtifactDigest const& value) const noexcept -> bool;
+
+  private:
+    StorageConfig const& storage_config_;
+    FileStorage<ObjectType::File, StoreMode::FirstWins, false> file_storage_;
+    bool uplink_;
+
+    explicit TreeStructureCache(
+        gsl::not_null<StorageConfig const*> const& storage_config,
+        std::size_t generation,
+        bool uplink) noexcept;
+
+    [[nodiscard]] auto LocalUplinkObject(
+        ArtifactDigest const& key,
+        TreeStructureCache const& latest) const noexcept -> bool;
+};
+
+#endif  // INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_CACHE_HPP