Execution API: support fetching a single artifact to memory

2 files changed, 23 insertions, 0 deletions

diff --git a/src/buildtool/execution_api/local/TARGETS b/src/buildtool/execution_api/local/TARGETS
index b9e056b8..1ea94d69 100644
--- a/src/buildtool/execution_api/local/TARGETS
+++ b/src/buildtool/execution_api/local/TARGETS
@@ -43,6 +43,7 @@
     , "config"
     , ["src/buildtool/common", "common"]
     , ["src/buildtool/common", "bazel_types"]
+    , ["src/buildtool/file_system", "file_system_manager"]
     ]
   }
 }
diff --git a/src/buildtool/execution_api/local/local_api.hpp b/src/buildtool/execution_api/local/local_api.hpp
index d699ad4f..e0de1598 100644
--- a/src/buildtool/execution_api/local/local_api.hpp
+++ b/src/buildtool/execution_api/local/local_api.hpp
@@ -31,6 +31,7 @@
 #include "src/buildtool/execution_api/common/execution_api.hpp"
 #include "src/buildtool/execution_api/git/git_api.hpp"
 #include "src/buildtool/execution_api/local/local_action.hpp"
+#include "src/buildtool/file_system/file_system_manager.hpp"
 #include "src/buildtool/logging/logger.hpp"
 #include "src/buildtool/storage/storage.hpp"
 
@@ -237,6 +238,27 @@ class LocalApi final : public IExecutionApi {
         return api->Upload(container, /*skip_find_missing=*/true);
     }
 
+    [[nodiscard]] auto RetrieveToMemory(
+        Artifact::ObjectInfo const& artifact_info)
+        -> std::optional<std::string> override {
+        std::optional<std::filesystem::path> location{};
+        if (IsTreeObject(artifact_info.type)) {
+            location = storage_->CAS().TreePath(artifact_info.digest);
+        }
+        else {
+            location = storage_->CAS().BlobPath(
+                artifact_info.digest, IsExecutableObject(artifact_info.type));
+        }
+        if (not location) {
+            return std::nullopt;
+        }
+        auto const content = FileSystemManager::ReadFile(*location);
+        if (not content) {
+            return std::nullopt;
+        }
+        return *content;
+    }
+
     [[nodiscard]] auto Upload(BlobContainer const& blobs,
                               bool /*skip_find_missing*/) noexcept
         -> bool final {