Add to ProtocolTraits static functions that provide protocol-specific behaviour

7 files changed, 32 insertions, 9 deletions

diff --git a/src/buildtool/common/TARGETS b/src/buildtool/common/TARGETS
index 1f280d78..4372db88 100644
--- a/src/buildtool/common/TARGETS
+++ b/src/buildtool/common/TARGETS
@@ -52,7 +52,7 @@
     , ["src/utils/cpp", "gsl"]
     , ["src/utils/cpp", "expected"]
     ]
-  , "private-deps": [["src/buildtool/crypto", "hasher"]]
+  , "private-deps": [["src/buildtool/crypto", "hasher"], "protocol_traits"]
   , "stage": ["src", "buildtool", "common"]
   }
 , "artifact_digest_factory":
@@ -68,7 +68,11 @@
     , ["src/utils/cpp", "expected"]
     ]
   , "private-deps":
-    ["bazel_digest_factory", "bazel_types", ["@", "gsl", "", "gsl"]]
+    [ "bazel_digest_factory"
+    , "bazel_types"
+    , ["@", "gsl", "", "gsl"]
+    , "protocol_traits"
+    ]
   , "stage": ["src", "buildtool", "common"]
   }
 , "common":
@@ -196,6 +200,7 @@
   { "type": ["@", "rules", "CC", "library"]
   , "name": ["protocol_traits"]
   , "hdrs": ["protocol_traits.hpp"]
+  , "deps": [["src/buildtool/crypto", "hash_function"]]
   , "stage": ["src", "buildtool", "common"]
   }
 }
diff --git a/src/buildtool/common/artifact_digest_factory.cpp b/src/buildtool/common/artifact_digest_factory.cpp
index dd9da28d..f3ea30c1 100644
--- a/src/buildtool/common/artifact_digest_factory.cpp
+++ b/src/buildtool/common/artifact_digest_factory.cpp
@@ -17,15 +17,17 @@
 #include "gsl/gsl"
 #include "src/buildtool/common/bazel_digest_factory.hpp"
 #include "src/buildtool/common/bazel_types.hpp"
+#include "src/buildtool/common/protocol_traits.hpp"
 
 auto ArtifactDigestFactory::Create(HashFunction::Type hash_type,
                                    std::string hash,
                                    std::size_t size,
                                    bool is_tree) noexcept
     -> expected<ArtifactDigest, std::string> {
-    const bool kTreesAllowed = hash_type == HashFunction::Type::GitSHA1;
     auto hash_info =
-        HashInfo::Create(hash_type, std::move(hash), kTreesAllowed and is_tree);
+        HashInfo::Create(hash_type,
+                         std::move(hash),
+                         ProtocolTraits::IsTreeAllowed(hash_type) and is_tree);
     if (not hash_info) {
         return unexpected{std::move(hash_info).error()};
     }
diff --git a/src/buildtool/common/bazel_digest_factory.cpp b/src/buildtool/common/bazel_digest_factory.cpp
index 4ff885aa..3a1f8519 100644
--- a/src/buildtool/common/bazel_digest_factory.cpp
+++ b/src/buildtool/common/bazel_digest_factory.cpp
@@ -16,12 +16,13 @@
 
 #include <utility>
 
+#include "src/buildtool/common/protocol_traits.hpp"
 #include "src/buildtool/crypto/hasher.hpp"
 
 auto BazelDigestFactory::Create(HashInfo const& hash_info,
                                 std::int64_t size) noexcept
     -> bazel_re::Digest {
-    auto hash = hash_info.HashType() == HashFunction::Type::GitSHA1
+    auto hash = ProtocolTraits::IsNative(hash_info.HashType())
                     ? Prefix(hash_info.Hash(), hash_info.IsTree())
                     : hash_info.Hash();
 
diff --git a/src/buildtool/common/protocol_traits.hpp b/src/buildtool/common/protocol_traits.hpp
index 49850233..f1a51cbe 100644
--- a/src/buildtool/common/protocol_traits.hpp
+++ b/src/buildtool/common/protocol_traits.hpp
@@ -15,6 +15,8 @@
 #ifndef INCLUDED_SRC_BUILDTOOL_COMMON_PROTOCOL_TRAITS_HPP
 #define INCLUDED_SRC_BUILDTOOL_COMMON_PROTOCOL_TRAITS_HPP
 
+#include "src/buildtool/crypto/hash_function.hpp"
+
 class ProtocolTraits final {
   public:
     [[nodiscard]] static auto Instance() noexcept -> ProtocolTraits& {
@@ -26,6 +28,16 @@ class ProtocolTraits final {
     }
     void SetCompatible(bool value = true) noexcept { compatible_ = value; }
 
+    inline static constexpr auto IsNative(HashFunction::Type hash_type) noexcept
+        -> bool {
+        return hash_type == HashFunction::Type::GitSHA1;
+    }
+
+    inline static constexpr auto IsTreeAllowed(
+        HashFunction::Type hash_type) noexcept -> bool {
+        return IsNative(hash_type);
+    }
+
   private:
     bool compatible_ = false;
 };
diff --git a/src/buildtool/crypto/TARGETS b/src/buildtool/crypto/TARGETS
index 4cacb13f..e4a84676 100644
--- a/src/buildtool/crypto/TARGETS
+++ b/src/buildtool/crypto/TARGETS
@@ -35,6 +35,7 @@
     , ["@", "gsl", "", "gsl"]
     , ["@", "fmt", "", "fmt"]
     , ["src/utils/cpp", "hex_string"]
+    , ["src/buildtool/common", "protocol_traits"]
     ]
   , "stage": ["src", "buildtool", "crypto"]
   }
diff --git a/src/buildtool/crypto/hash_info.cpp b/src/buildtool/crypto/hash_info.cpp
index 3b14d445..4fb87161 100644
--- a/src/buildtool/crypto/hash_info.cpp
+++ b/src/buildtool/crypto/hash_info.cpp
@@ -16,6 +16,7 @@
 
 #include "fmt/core.h"
 #include "gsl/gsl"  // Ensures
+#include "src/buildtool/common/protocol_traits.hpp"
 #include "src/buildtool/crypto/hasher.hpp"
 #include "src/utils/cpp/hex_string.hpp"
 
@@ -58,7 +59,7 @@ auto HashInfo::HashData(HashFunction hash_function,
     return HashInfo{
         hash_digest.HexString(),
         hash_function.GetType(),
-        is_tree and hash_function.GetType() == HashFunction::Type::GitSHA1};
+        is_tree and ProtocolTraits::IsTreeAllowed(hash_function.GetType())};
 }
 
 auto HashInfo::HashFile(HashFunction hash_function,
@@ -85,7 +86,7 @@ auto HashInfo::ValidateInput(HashFunction::Type type,
                              std::string const& hash,
                              bool is_tree) noexcept
     -> std::optional<std::string> {
-    if (type != HashFunction::Type::GitSHA1 and is_tree) {
+    if (is_tree and not ProtocolTraits::IsTreeAllowed(type)) {
         return fmt::format(
             "HashInfo: hash {} is expected to be {}.\nTrees are "
             "not allowed in this mode.",
diff --git a/src/buildtool/execution_api/remote/bazel/bazel_network_reader.cpp b/src/buildtool/execution_api/remote/bazel/bazel_network_reader.cpp
index 4b411d91..d78a63de 100644
--- a/src/buildtool/execution_api/remote/bazel/bazel_network_reader.cpp
+++ b/src/buildtool/execution_api/remote/bazel/bazel_network_reader.cpp
@@ -18,6 +18,7 @@
 
 #include "src/buildtool/common/artifact_digest_factory.hpp"
 #include "src/buildtool/common/bazel_digest_factory.hpp"
+#include "src/buildtool/common/protocol_traits.hpp"
 #include "src/buildtool/execution_api/bazel_msg/bazel_msg_factory.hpp"
 #include "src/buildtool/execution_api/common/message_limits.hpp"
 #include "src/buildtool/file_system/file_system_manager.hpp"
@@ -71,7 +72,7 @@ auto BazelNetworkReader::ReadDirectory(ArtifactDigest const& digest)
 
 auto BazelNetworkReader::ReadGitTree(ArtifactDigest const& digest)
     const noexcept -> std::optional<GitRepo::tree_entries_t> {
-    ExpectsAudit(hash_function_.GetType() == HashFunction::Type::GitSHA1);
+    ExpectsAudit(ProtocolTraits::IsNative(hash_function_.GetType()));
 
     auto read_blob = ReadSingleBlob(digest);
     if (not read_blob) {
@@ -145,7 +146,7 @@ auto BazelNetworkReader::DumpBlob(Artifact::ObjectInfo const& info,
 auto BazelNetworkReader::MakeAuxiliaryMap(
     std::vector<bazel_re::Directory>&& full_tree) const noexcept
     -> std::optional<DirectoryMap> {
-    ExpectsAudit(hash_function_.GetType() == HashFunction::Type::PlainSHA256);
+    ExpectsAudit(not ProtocolTraits::IsNative(hash_function_.GetType()));
 
     DirectoryMap result;
     result.reserve(full_tree.size());