Move downstepping to subobjects to a library

... in order to make that functionality reusable

5 files changed, 181 insertions, 92 deletions

diff --git a/src/buildtool/execution_api/utils/TARGETS b/src/buildtool/execution_api/utils/TARGETS
new file mode 100644
index 00000000..20b65c18
--- /dev/null
+++ b/src/buildtool/execution_api/utils/TARGETS
@@ -0,0 +1,18 @@
+{ "subobject":
+  { "type": ["@", "rules", "CC", "library"]
+  , "name": ["subobject"]
+  , "hdrs": ["subobject.hpp"]
+  , "srcs": ["subobject.cpp"]
+  , "deps":
+    [ ["src/buildtool/common", "common"]
+    , ["src/buildtool/execution_api/common", "common"]
+    , ["@", "gsl", "", "gsl"]
+    ]
+  , "private-deps":
+    [ ["src/buildtool/compatibility", "compatibility"]
+    , ["src/buildtool/execution_api/bazel_msg", "bazel_msg_factory"]
+    , ["src/buildtool/logging", "logging"]
+    ]
+  , "stage": ["src", "buildtool", "execution_api", "utils"]
+  }
+}
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
diff --git a/src/buildtool/execution_api/utils/subobject.hpp b/src/buildtool/execution_api/utils/subobject.hpp
new file mode 100644
index 00000000..85fc7bdb
--- /dev/null
+++ b/src/buildtool/execution_api/utils/subobject.hpp
@@ -0,0 +1,34 @@
+// 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.
+
+#ifndef INCLUDED_SRC_BUILDTOOL_EXECUTION_API_UTILS_SUBOBJECT_HPP
+#define INCLUDED_SRC_BUILDTOOL_EXECUTION_API_UTILS_SUBOBJECT_HPP
+
+#ifndef BOOTSTRAP_BUILD_TOOL
+
+#include <filesystem>
+#include <optional>
+
+#include "gsl/gsl"
+#include "src/buildtool/common/artifact.hpp"
+#include "src/buildtool/execution_api/common/execution_api.hpp"
+
+auto RetrieveSubPathId(Artifact::ObjectInfo object_info,
+                       gsl::not_null<IExecutionApi*> const& api,
+                       const std::filesystem::path& sub_path)
+    -> std::optional<Artifact::ObjectInfo>;
+
+#endif
+
+#endif
diff --git a/src/buildtool/main/TARGETS b/src/buildtool/main/TARGETS
index 8ff214d0..b74a5fe4 100644
--- a/src/buildtool/main/TARGETS
+++ b/src/buildtool/main/TARGETS
@@ -83,9 +83,9 @@
   , "private-deps":
     [ ["src/buildtool/compatibility", "compatibility"]
     , ["src/buildtool/crypto", "hash_function"]
-    , ["src/buildtool/execution_api/bazel_msg", "bazel_msg_factory"]
     , ["src/buildtool/execution_api/remote", "config"]
     , ["src/buildtool/logging", "logging"]
+    , ["src/buildtool/execution_api/utils", "subobject"]
     ]
   }
 , "analyse":
diff --git a/src/buildtool/main/install_cas.cpp b/src/buildtool/main/install_cas.cpp
index 99867de8..622e7a1f 100644
--- a/src/buildtool/main/install_cas.cpp
+++ b/src/buildtool/main/install_cas.cpp
@@ -17,7 +17,7 @@
 #include "src/buildtool/compatibility/compatibility.hpp"
 #include "src/buildtool/crypto/hash_function.hpp"
 #ifndef BOOTSTRAP_BUILD_TOOL
-#include "src/buildtool/execution_api/bazel_msg/bazel_msg_factory.hpp"
+#include "src/buildtool/execution_api/utils/subobject.hpp"
 #endif
 #include "src/buildtool/execution_api/remote/config.hpp"
 
@@ -81,96 +81,13 @@ auto FetchAndInstallArtifacts(
 
     if (clargs.sub_path) {
         std::filesystem::path sofar{};
-        for (auto const& segment : *clargs.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 false;
-            }
-            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;
+        auto new_object_info =
+            RetrieveSubPathId(object_info, api, *clargs.sub_path);
+        if (new_object_info) {
+            object_info = *new_object_info;
+        }
+        else {
+            return false;
         }
     }