remote API: support uploading files from the file system

Allow implementations to have a specialized way of uploading a file
owned by the build process to the applicable cas, both as file, as
well as as tree object (in native mode).

If no implementation is provided, the default is to read the file
into memory and use the Upload method.

3 files changed, 69 insertions, 3 deletions

diff --git a/src/buildtool/execution_api/common/TARGETS b/src/buildtool/execution_api/common/TARGETS
index 4a9c60e1..1d0431f0 100644
--- a/src/buildtool/execution_api/common/TARGETS
+++ b/src/buildtool/execution_api/common/TARGETS
@@ -7,18 +7,20 @@
     , "execution_action.hpp"
     , "execution_response.hpp"
     ]
+  , "srcs": ["execution_api.cpp"]
   , "deps":
     [ ["@", "gsl", "", "gsl"]
     , ["src/buildtool/common", "common"]
     , ["src/buildtool/crypto", "hash_function"]
     , ["src/buildtool/execution_api/bazel_msg", "bazel_msg"]
     , ["src/buildtool/execution_api/bazel_msg", "bazel_msg_factory"]
-    , ["src/utils/cpp", "hex_string"]
-    , ["src/utils/cpp", "gsl"]
+    , ["src/buildtool/file_system", "file_system_manager"]
+    , ["src/buildtool/file_system", "object_type"]
     , ["src/buildtool/logging", "logging"]
+    , ["src/utils/cpp", "gsl"]
+    , ["src/utils/cpp", "hex_string"]
     ]
   , "stage": ["src", "buildtool", "execution_api", "common"]
-  , "private-deps": [["src/buildtool/file_system", "object_type"]]
   }
 , "bytestream-common":
   { "type": ["@", "rules", "CC", "library"]
diff --git a/src/buildtool/execution_api/common/execution_api.cpp b/src/buildtool/execution_api/common/execution_api.cpp
new file mode 100644
index 00000000..f91dee43
--- /dev/null
+++ b/src/buildtool/execution_api/common/execution_api.cpp
@@ -0,0 +1,56 @@
+// 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/common/execution_api.hpp"
+
+#include "src/buildtool/execution_api/bazel_msg/bazel_blob_container.hpp"
+#include "src/buildtool/file_system/file_system_manager.hpp"
+
+#include <gsl/gsl>
+
+[[nodiscard]] auto IExecutionApi::UploadFile(
+    std::filesystem::path const& file_path,
+    ObjectType type) noexcept -> bool {
+    auto data = FileSystemManager::ReadFile(file_path);
+    if (not data) {
+        return false;
+    }
+    ArtifactDigest digest{};
+    switch (type) {
+        case ObjectType::File:
+            digest = ArtifactDigest::Create<ObjectType::File>(*data);
+            break;
+        case ObjectType::Executable:
+            digest = ArtifactDigest::Create<ObjectType::Executable>(*data);
+            break;
+        case ObjectType::Tree:
+            digest = ArtifactDigest::Create<ObjectType::Tree>(*data);
+            break;
+        case ObjectType::Symlink:
+            digest = ArtifactDigest::Create<ObjectType::Symlink>(*data);
+            break;
+        default:
+            Ensures(false);  // unreachable
+            return false;
+    }
+    BlobContainer container{};
+    try {
+        auto exec = IsExecutableObject(type);
+        container.Emplace(BazelBlob{digest, *data, exec});
+    } catch (std::exception const& ex) {
+        Logger::Log(LogLevel::Error, "failed to emplace blob: ", ex.what());
+        return false;
+    }
+    return Upload(container);
+}
diff --git a/src/buildtool/execution_api/common/execution_api.hpp b/src/buildtool/execution_api/common/execution_api.hpp
index 37abd5ea..d6ec49fb 100644
--- a/src/buildtool/execution_api/common/execution_api.hpp
+++ b/src/buildtool/execution_api/common/execution_api.hpp
@@ -15,6 +15,7 @@
 #ifndef INCLUDED_SRC_BUILDTOOL_EXECUTION_API_COMMON_EXECUTION_APIHPP
 #define INCLUDED_SRC_BUILDTOOL_EXECUTION_API_COMMON_EXECUTION_APIHPP
 
+#include <filesystem>
 #include <map>
 #include <memory>
 #include <optional>
@@ -27,6 +28,7 @@
 #include "src/buildtool/execution_api/bazel_msg/bazel_blob_container.hpp"
 #include "src/buildtool/execution_api/bazel_msg/bazel_msg_factory.hpp"
 #include "src/buildtool/execution_api/common/execution_action.hpp"
+#include "src/buildtool/file_system/object_type.hpp"
 
 /// \brief Abstract remote execution API
 /// Can be used to create actions.
@@ -116,6 +118,12 @@ class IExecutionApi {
                                       bool skip_find_missing = false) noexcept
         -> bool = 0;
 
+    /// \brief Upload a file to CAS as an object of the specified type.
+    /// It may be assumed that the file is owned entirely by the build process.
+    [[nodiscard]] virtual auto UploadFile(
+        std::filesystem::path const& file_path,
+        ObjectType type) noexcept -> bool;
+
     [[nodiscard]] virtual auto UploadTree(
         std::vector<DependencyGraph::NamedArtifactNodePtr> const&
             artifacts) noexcept -> std::optional<ArtifactDigest> = 0;