Move downstepping to subobjects to a library

... in order to make that functionality reusable

1 files changed, 120 insertions, 0 deletions

diff --git a/src/buildtool/execution_api/utils/subobject.cpp b/src/buildtool/execution_api/utils/subobject.cpp
new file mode 100644
index 00000000..46ec58a7
--- /dev/null
+++ b/src/buildtool/execution_api/utils/subobject.cpp
@@ -0,0 +1,120 @@
+// Copyright 2023 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/execution_api/utils/subobject.hpp"
+#ifndef BOOTSTRAP_BUILD_TOOL
+
+#include "src/buildtool/compatibility/compatibility.hpp"
+#include "src/buildtool/execution_api/bazel_msg/bazel_msg_factory.hpp"
+#include "src/buildtool/logging/log_level.hpp"
+#include "src/buildtool/logging/logger.hpp"
+
+auto RetrieveSubPathId(Artifact::ObjectInfo object_info,
+                       gsl::not_null<IExecutionApi*> const& api,
+                       const std::filesystem::path& sub_path)
+    -> std::optional<Artifact::ObjectInfo> {
+
+    std::filesystem::path sofar{};
+    for (auto const& segment : sub_path) {
+        if (object_info.type != ObjectType::Tree) {
+            Logger::Log(LogLevel::Warning,
+                        "Non-tree found at path '{}', cannot follow to '{}'",
+                        sofar.string(),
+                        segment.string());
+            break;
+        }
+        auto data = api->RetrieveToMemory(object_info);
+        if (not data) {
+            Logger::Log(LogLevel::Error,
+                        "Failed to retrieve artifact {} at path '{}'",
+                        object_info.ToString(),
+                        sofar.string());
+            return std::nullopt;
+        }
+        if (Compatibility::IsCompatible()) {
+            auto directory =
+                BazelMsgFactory::MessageFromString<bazel_re::Directory>(*data);
+            if (not directory) {
+                Logger::Log(LogLevel::Warning,
+                            "Failed to parse directory message at path '{}'",
+                            sofar.string());
+                break;
+            }
+            std::optional<Artifact::ObjectInfo> new_object_info{};
+            if (not BazelMsgFactory::ReadObjectInfosFromDirectory(
+                    *directory,
+                    [&new_object_info, &segment](auto path, auto info) {
+                        if (path == segment) {
+                            new_object_info = info;
+                        }
+                        return true;
+                    })) {
+                Logger::Log(LogLevel::Warning,
+                            "Failed to process directory message at path '{}'",
+                            sofar.string());
+                break;
+            }
+            if (not new_object_info) {
+                Logger::Log(LogLevel::Warning,
+                            "Entry {} not found at path '{}'",
+                            segment.string(),
+                            sofar.string());
+                break;
+            }
+            object_info = *new_object_info;
+        }
+        else {
+            auto entries = GitRepo::ReadTreeData(
+                *data,
+                HashFunction::ComputeTreeHash(*data).Bytes(),
+                [](auto const& /*unused*/) { return true; },
+                /*is_hex_id=*/false);
+            if (not entries) {
+                Logger::Log(LogLevel::Warning,
+                            "Failed to parse tree {} at path '{}'",
+                            object_info.ToString(),
+                            sofar.string());
+                break;
+            }
+            std::optional<Artifact::ObjectInfo> new_object_info{};
+            if (not BazelMsgFactory::ReadObjectInfosFromGitTree(
+                    *entries,
+                    [&new_object_info, &segment](auto path, auto info) {
+                        if (path == segment) {
+                            new_object_info = info;
+                        }
+                        return true;
+                    })) {
+                Logger::Log(LogLevel::Warning,
+                            "Failed to process tree entries at path '{}'",
+                            sofar.string());
+                break;
+            }
+
+            if (not new_object_info) {
+                Logger::Log(LogLevel::Warning,
+                            "Entry {} not found at path '{}'",
+                            segment.string(),
+                            sofar.string());
+                break;
+            }
+            object_info = *new_object_info;
+        }
+        sofar /= segment;
+    }
+
+    return object_info;
+}
+
+#endif