TreeStructureUtils: export from git

5 files changed, 78 insertions, 33 deletions

diff --git a/src/buildtool/computed_roots/TARGETS b/src/buildtool/computed_roots/TARGETS
index fde38693..4d620db3 100644
--- a/src/buildtool/computed_roots/TARGETS
+++ b/src/buildtool/computed_roots/TARGETS
@@ -78,7 +78,6 @@
     , ["src/buildtool/crypto", "hash_function"]
     , ["src/buildtool/execution_api/common", "api_bundle"]
     , ["src/buildtool/execution_api/common", "common"]
-    , ["src/buildtool/execution_api/git", "git"]
     , ["src/buildtool/execution_api/local", "config"]
     , ["src/buildtool/execution_api/local", "context"]
     , ["src/buildtool/execution_api/local", "local"]
diff --git a/src/buildtool/computed_roots/evaluate.cpp b/src/buildtool/computed_roots/evaluate.cpp
index 0905c240..ffac5e04 100644
--- a/src/buildtool/computed_roots/evaluate.cpp
+++ b/src/buildtool/computed_roots/evaluate.cpp
@@ -46,7 +46,6 @@
 #include "src/buildtool/crypto/hash_function.hpp"
 #include "src/buildtool/execution_api/common/api_bundle.hpp"
 #include "src/buildtool/execution_api/common/execution_api.hpp"
-#include "src/buildtool/execution_api/git/git_api.hpp"
 #include "src/buildtool/execution_api/local/config.hpp"
 #include "src/buildtool/execution_api/local/context.hpp"
 #include "src/buildtool/execution_api/local/local_api.hpp"
@@ -411,6 +410,7 @@ void ComputeTreeStructureAndFill(
     if (not resolved_hash) {
         // If the tree is not in the storage, it must be added:
         if (not storage.CAS().TreePath(*digest).has_value()) {
+            std::vector<std::filesystem::path> known_repos;
             auto const path_to_git_cas = ref_root.GetGitCasRoot();
             if (not path_to_git_cas) {
                 std::invoke(*logger,
@@ -420,45 +420,36 @@ void ComputeTreeStructureAndFill(
                             true);
                 return;
             }
+            known_repos.push_back(*path_to_git_cas);
+            known_repos.push_back(native_storage_config.GitRoot());
 
-            RepositoryConfig root_config{};
-            if (not root_config.SetGitCAS(*path_to_git_cas)) {
-                std::invoke(
-                    *logger,
-                    fmt::format("Failed to set git cas for {}", key.ToString()),
-                    true);
+            auto in_cas = TreeStructureUtils::ExportFromGit(
+                *digest, known_repos, native_local_api);
+            if (not in_cas.has_value()) {
+                std::invoke(*logger, std::move(in_cas).error(), /*fatal=*/true);
                 return;
             }
+        }
 
-            GitApi const git_api{&root_config};
-            if (not git_api.RetrieveToCas(
-                    {Artifact::ObjectInfo{*digest, ObjectType::Tree}},
-                    native_local_api) or
-                not storage.CAS().TreePath(*digest).has_value()) {
-                std::invoke(*logger,
-                            fmt::format("Failed to retrieve {} to CAS for {}",
-                                        digest->hash(),
-                                        key.ToString()),
-                            true);
+        if (storage.CAS().TreePath(*digest).has_value()) {
+            // Compute tree structure and add it to the cache:
+            auto const tree_structure = TreeStructureUtils::Compute(
+                *digest, storage, tree_structure_cache);
+            if (not tree_structure) {
+                std::invoke(*logger, tree_structure.error(), /*fatal=*/true);
                 return;
             }
-        }
 
-        // Compute tree structure and add it to the cache:
-        auto const tree_structure =
-            TreeStructureUtils::Compute(*digest, storage, tree_structure_cache);
-        if (not tree_structure) {
-            std::invoke(*logger, tree_structure.error(), /*fatal=*/true);
-            return;
-        }
-
-        auto to_git = TreeStructureUtils::ImportToGit(
-            *tree_structure, native_local_api, native_storage_config, git_lock);
-        if (not to_git.has_value()) {
-            std::invoke(*logger, std::move(to_git).error(), /*fatal=*/true);
-            return;
+            auto to_git = TreeStructureUtils::ImportToGit(*tree_structure,
+                                                          native_local_api,
+                                                          native_storage_config,
+                                                          git_lock);
+            if (not to_git.has_value()) {
+                std::invoke(*logger, std::move(to_git).error(), /*fatal=*/true);
+                return;
+            }
+            resolved_hash = tree_structure->hash();
         }
-        resolved_hash = tree_structure->hash();
     }
 
     if (not resolved_hash) {
diff --git a/src/buildtool/tree_structure/TARGETS b/src/buildtool/tree_structure/TARGETS
index 45244119..0c9dc676 100644
--- a/src/buildtool/tree_structure/TARGETS
+++ b/src/buildtool/tree_structure/TARGETS
@@ -38,8 +38,10 @@
   , "private-deps":
     [ ["@", "fmt", "", "fmt"]
     , ["src/buildtool/common", "artifact_digest_factory"]
+    , ["src/buildtool/common", "config"]
     , ["src/buildtool/common", "protocol_traits"]
     , ["src/buildtool/crypto", "hash_function"]
+    , ["src/buildtool/execution_api/git", "git"]
     , ["src/buildtool/file_system", "file_system_manager"]
     , ["src/buildtool/file_system", "git_repo"]
     , ["src/buildtool/file_system", "object_type"]
diff --git a/src/buildtool/tree_structure/tree_structure_utils.cpp b/src/buildtool/tree_structure/tree_structure_utils.cpp
index b607cb9f..7cc04b6f 100644
--- a/src/buildtool/tree_structure/tree_structure_utils.cpp
+++ b/src/buildtool/tree_structure/tree_structure_utils.cpp
@@ -15,6 +15,7 @@
 #include "src/buildtool/tree_structure/tree_structure_utils.hpp"
 
 #include <algorithm>
+#include <cstddef>
 #include <filesystem>
 #include <functional>
 #include <memory>
@@ -27,7 +28,9 @@
 #include "src/buildtool/common/artifact.hpp"
 #include "src/buildtool/common/artifact_digest_factory.hpp"
 #include "src/buildtool/common/protocol_traits.hpp"
+#include "src/buildtool/common/repository_config.hpp"
 #include "src/buildtool/crypto/hash_function.hpp"
+#include "src/buildtool/execution_api/git/git_api.hpp"
 #include "src/buildtool/file_system/file_system_manager.hpp"
 #include "src/buildtool/file_system/git_repo.hpp"
 #include "src/buildtool/file_system/object_type.hpp"
@@ -198,3 +201,38 @@ auto TreeStructureUtils::ImportToGit(
     }
     return *digest;
 }
+
+auto TreeStructureUtils::ExportFromGit(
+    ArtifactDigest const& tree,
+    std::vector<std::filesystem::path> const& source_repos,
+    IExecutionApi const& target_api) noexcept -> expected<bool, std::string> {
+    if (not tree.IsTree() or not ProtocolTraits::IsNative(tree.GetHashType())) {
+        return unexpected{fmt::format("Not a git tree: {}", tree.hash())};
+    }
+
+    // Find git repo that contains the tree:
+    std::filesystem::path const* repo = nullptr;
+    for (std::size_t i = 0; i < source_repos.size() and repo == nullptr; ++i) {
+        auto in_repo = GitRepo::IsTreeInRepo(source_repos[i], tree.hash());
+        if (not in_repo.has_value()) {
+            return unexpected{std::move(in_repo).error()};
+        }
+        if (*in_repo) {
+            repo = &source_repos[i];
+        }
+    }
+
+    // Check that at least one repo contains the tree:
+    if (repo == nullptr) {
+        return false;
+    }
+
+    RepositoryConfig repo_config{};
+    if (not repo_config.SetGitCAS(*repo)) {
+        return unexpected{
+            fmt::format("Failed to set git cas at {}", repo->string())};
+    }
+    auto const git_api = GitApi{&repo_config};
+    return git_api.RetrieveToCas({Artifact::ObjectInfo{tree, ObjectType::Tree}},
+                                 target_api);
+}
diff --git a/src/buildtool/tree_structure/tree_structure_utils.hpp b/src/buildtool/tree_structure/tree_structure_utils.hpp
index df2f9f5e..4f908640 100644
--- a/src/buildtool/tree_structure/tree_structure_utils.hpp
+++ b/src/buildtool/tree_structure/tree_structure_utils.hpp
@@ -15,8 +15,10 @@
 #ifndef INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_UTILS_HPP
 #define INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_UTILS_HPP
 
+#include <filesystem>
 #include <mutex>
 #include <string>
+#include <vector>
 
 #include "gsl/gsl"
 #include "src/buildtool/common/artifact_digest.hpp"
@@ -59,6 +61,19 @@ class TreeStructureUtils final {
         StorageConfig const& target_config,
         gsl::not_null<std::mutex*> const& tagging_lock) noexcept
         -> expected<ArtifactDigest, std::string>;
+
+    /// \brief Export a tree from source git repositories to target api. Uses
+    /// regular GitApi for retrieval from git and doesn't perform rehashing.
+    /// \param tree           Tree to export
+    /// \param source_repos   Repositories to check
+    /// \param target_api     Api to export the tree to
+    /// \return True if target api contains tree after the call, false if none
+    /// of source repositories contain tree, or an error message on failure.
+    [[nodiscard]] static auto ExportFromGit(
+        ArtifactDigest const& tree,
+        std::vector<std::filesystem::path> const& source_repos,
+        IExecutionApi const& target_api) noexcept
+        -> expected<bool, std::string>;
 };
 
 #endif  // INCLUDED_SRC_BUILDTOOL_TREE_STRUCTURE_TREE_STRUCTURE_UTILS_HPP