serve service: Respond also with digest in serve repository tree RPCs

...besides the simple Git hash, if syncing was done. This way one
can know what digest to ask for from the remote. The serve client
also needs to now know what hash function the remote expects.

The serve service proto file is updated accordingly.

1 files changed, 41 insertions, 5 deletions

diff --git a/src/buildtool/serve_api/remote/source_tree_client.cpp b/src/buildtool/serve_api/remote/source_tree_client.cpp
index 994fcc21..f3538ca3 100644
--- a/src/buildtool/serve_api/remote/source_tree_client.cpp
+++ b/src/buildtool/serve_api/remote/source_tree_client.cpp
@@ -16,6 +16,7 @@
 
 #include "src/buildtool/serve_api/remote/source_tree_client.hpp"
 
+#include "src/buildtool/common/artifact_digest_factory.hpp"
 #include "src/buildtool/common/remote/client_common.hpp"
 #include "src/buildtool/logging/log_level.hpp"
 
@@ -61,7 +62,9 @@ auto PragmaSpecialToSymlinksResolve(
 
 SourceTreeClient::SourceTreeClient(
     ServerAddress const& address,
-    gsl::not_null<RemoteContext const*> const& remote_context) noexcept {
+    gsl::not_null<HashFunction const*> const& hash_function,
+    gsl::not_null<RemoteContext const*> const& remote_context) noexcept
+    : hash_function_{*hash_function} {
     stub_ =
         justbuild::just_serve::SourceTree::NewStub(CreateChannelWithCredentials(
             address.host, address.port, remote_context->auth));
@@ -95,7 +98,18 @@ auto SourceTreeClient::ServeCommitTree(std::string const& commit_id,
                 ? GitLookupError::Fatal
                 : GitLookupError::NotFound};
     }
-    return response.tree();  // success
+    TreeResult result = {response.tree(), std::nullopt};
+    // if asked to sync, get digest from response
+    if (sync_tree) {
+        auto digest = ArtifactDigestFactory::FromBazel(hash_function_.GetType(),
+                                                       response.digest());
+        if (not digest) {
+            logger_.Emit(LogLevel::Debug, std::move(digest).error());
+            return unexpected{GitLookupError::Fatal};
+        }
+        result.digest = *std::move(digest);
+    }
+    return result;  // success
 }
 
 auto SourceTreeClient::ServeArchiveTree(
@@ -131,7 +145,18 @@ auto SourceTreeClient::ServeArchiveTree(
                 ? GitLookupError::Fatal
                 : GitLookupError::NotFound};
     }
-    return response.tree();  // success
+    TreeResult result = {response.tree(), std::nullopt};
+    // if asked to sync, get digest from response
+    if (sync_tree) {
+        auto digest = ArtifactDigestFactory::FromBazel(hash_function_.GetType(),
+                                                       response.digest());
+        if (not digest) {
+            logger_.Emit(LogLevel::Debug, std::move(digest).error());
+            return unexpected{GitLookupError::Fatal};
+        }
+        result.digest = *std::move(digest);
+    }
+    return result;  // success
 }
 
 auto SourceTreeClient::ServeDistdirTree(
@@ -166,7 +191,18 @@ auto SourceTreeClient::ServeDistdirTree(
                 ? GitLookupError::Fatal
                 : GitLookupError::NotFound};
     }
-    return response.tree();  // success
+    TreeResult result = {response.tree(), std::nullopt};
+    // if asked to sync, get digest from response
+    if (sync_tree) {
+        auto digest = ArtifactDigestFactory::FromBazel(hash_function_.GetType(),
+                                                       response.digest());
+        if (not digest) {
+            logger_.Emit(LogLevel::Debug, std::move(digest).error());
+            return unexpected{GitLookupError::Fatal};
+        }
+        result.digest = *std::move(digest);
+    }
+    return result;  // success
 }
 
 auto SourceTreeClient::ServeForeignFileTree(const std::string& content,
@@ -199,7 +235,7 @@ auto SourceTreeClient::ServeForeignFileTree(const std::string& content,
                 ? GitLookupError::Fatal
                 : GitLookupError::NotFound};
     }
-    return response.tree();  // success
+    return TreeResult{response.tree(), std::nullopt};  // success
 }
 
 auto SourceTreeClient::ServeContent(std::string const& content) const noexcept