1 files changed, 151 insertions, 0 deletions
diff --git a/src/buildtool/tree_structure/tree_structure_cache.cpp b/src/buildtool/tree_structure/tree_structure_cache.cpp
new file mode 100644
index 00000000..21515e59
--- /dev/null
+++ b/src/buildtool/tree_structure/tree_structure_cache.cpp
@@ -0,0 +1,151 @@
+// 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.
+
+#include "src/buildtool/tree_structure/tree_structure_cache.hpp"
+
+#include <filesystem>
+#include <fstream>
+#include <string>
+#include <utility>
+
+#include "nlohmann/json.hpp"
+#include "src/buildtool/common/artifact_digest_factory.hpp"
+#include "src/buildtool/crypto/hash_function.hpp"
+#include "src/buildtool/file_system/file_system_manager.hpp"
+#include "src/buildtool/storage/storage.hpp"
+#include "src/utils/cpp/expected.hpp"
+
+namespace {
+inline constexpr std::size_t kHash = 0;
+inline constexpr std::size_t kSize = 1;
+inline constexpr std::size_t kTree = 2;
+
+[[nodiscard]] auto IsInCas(Storage const& storage,
+                           ArtifactDigest const& digest) -> bool {
+    if (digest.IsTree()) {
+        return storage.CAS().TreePath(digest).has_value();
+    }
+
+    static constexpr bool kIsExecutable = true;
+    return storage.CAS().BlobPathNoSync(digest, kIsExecutable).has_value() or
+           storage.CAS().BlobPathNoSync(digest, not kIsExecutable).has_value();
+}
+
+[[nodiscard]] auto ToJson(ArtifactDigest const& digest)
+    -> std::optional<nlohmann::json> {
+    try {
+        return nlohmann::json{digest.hash(), digest.size(), digest.IsTree()};
+    } catch (...) {
+        return std::nullopt;
+    }
+}
+
+[[nodiscard]] auto Parse(HashFunction::Type hash_type,
+                         std::filesystem::path const& path) noexcept
+    -> std::optional<ArtifactDigest> {
+    try {
+        std::ifstream stream(path);
+        nlohmann::json j = nlohmann::json::parse(stream);
+        auto result = ArtifactDigestFactory::Create(
+            hash_type,
+            j.at(kHash).template get<std::string>(),
+            j.at(kSize).template get<std::size_t>(),
+            j.at(kTree).template get<bool>());
+        if (result) {
+            return *std::move(result);
+        }
+    } catch (...) {
+        return std::nullopt;
+    }
+    return std::nullopt;
+}
+}  // namespace
+
+TreeStructureCache::TreeStructureCache(
+    gsl::not_null<StorageConfig const*> const& storage_config) noexcept
+    : TreeStructureCache(storage_config, 0, /*uplink=*/true) {}
+
+TreeStructureCache::TreeStructureCache(
+    gsl::not_null<StorageConfig const*> const& storage_config,
+    std::size_t generation,
+    bool uplink) noexcept
+    : storage_config_{*storage_config},
+      file_storage_{storage_config_.RepositoryGenerationRoot(generation) /
+                    "tree_structure"},
+      uplink_{uplink} {}
+
+auto TreeStructureCache::Get(ArtifactDigest const& key) const noexcept
+    -> std::optional<ArtifactDigest> {
+    // Check key object is in the storage AND trigger uplinking if needed
+    auto const path = file_storage_.GetPath(key.hash());
+    if (uplink_ and not LocalUplinkObject(key, *this)) {
+        return std::nullopt;
+    }
+
+    if (not FileSystemManager::IsFile(path)) {
+        return std::nullopt;
+    }
+    return Parse(storage_config_.hash_function.GetType(), path);
+}
+
+auto TreeStructureCache::Set(ArtifactDigest const& key,
+                             ArtifactDigest const& value) const noexcept
+    -> bool {
+    auto result = Get(key);
+    if (result) {
+        return *result == value;
+    }
+
+    auto const storage = Storage::Create(&storage_config_);
+    // Check both key and value are in the storage and in the latest generation.
+    if (not IsInCas(storage, key) or not IsInCas(storage, value)) {
+        return false;
+    }
+
+    try {
+        auto j = ToJson(value);
+        if (not j) {
+            return false;
+        }
+        return file_storage_.AddFromBytes(key.hash(), j->dump());
+    } catch (...) {
+        return false;
+    }
+}
+
+auto TreeStructureCache::LocalUplinkObject(
+    ArtifactDigest const& key,
+    TreeStructureCache const& latest) const noexcept -> bool {
+    auto const storage = Storage::Create(&storage_config_);
+    // ensure key is present in the storage AND is in the latest generation
+    if (not IsInCas(storage, key)) {
+        return false;
+    }
+    for (std::size_t i = 0; i < storage_config_.num_generations; ++i) {
+        TreeStructureCache const generation_cache(&storage_config_, i, false);
+        auto const path = generation_cache.file_storage_.GetPath(key.hash());
+        if (not FileSystemManager::IsFile(path)) {
+            continue;
+        }
+        auto digest = Parse(storage_config_.hash_function.GetType(), path);
+        // ensure value is present in the storage AND is in the latest
+        // generation
+        if (not digest or not IsInCas(storage, *digest)) {
+            return false;
+        }
+        static constexpr bool kIsOwner = true;
+        return latest.file_storage_.AddFromFile(key.hash(), path, kIsOwner);
+    }
+    return false;
+}