Faster protobuf serialization without `std::string` indirection

2 files changed, 25 insertions, 13 deletions

diff --git a/storageapi/src/tests/mbusprot/storageprotocoltest.cpp b/storageapi/src/tests/mbusprot/storageprotocoltest.cpp
index 5a5d53ce950..fd375fd6e74 100644
--- a/storageapi/src/tests/mbusprot/storageprotocoltest.cpp
+++ b/storageapi/src/tests/mbusprot/storageprotocoltest.cpp
@@ -16,6 +16,7 @@
 #include <vespa/document/test/make_bucket_space.h>
 #include <vespa/vespalib/util/growablebytebuffer.h>
 #include <vespa/vespalib/objects/nbostream.h>
+
 #include <iomanip>
 #include <sstream>
 
@@ -35,6 +36,15 @@ using document::test::makeBucketSpace;
 using storage::lib::ClusterState;
 using vespalib::string;
 
+namespace vespalib {
+
+// Needed for GTest to properly understand how to print Version values.
+void PrintTo(const vespalib::Version& v, std::ostream* os) {
+    *os << v.toString();
+}
+
+}
+
 namespace storage::api {
 
 struct StorageProtocolTest : TestWithParam<vespalib::Version> {
diff --git a/storageapi/src/vespa/storageapi/mbusprot/protocolserialization7.cpp b/storageapi/src/vespa/storageapi/mbusprot/protocolserialization7.cpp
index 979e4162a7a..1692a1fcfcd 100644
--- a/storageapi/src/vespa/storageapi/mbusprot/protocolserialization7.cpp
+++ b/storageapi/src/vespa/storageapi/mbusprot/protocolserialization7.cpp
@@ -97,12 +97,13 @@ void write_request_header(vespalib::GrowableByteBuffer& buf, const api::StorageC
     hdr.set_source_index(cmd.getSourceIndex());
     hdr.set_loadtype_id(cmd.getLoadType().getId());
 
-    char dest[128]; // Only primitive fields, should be plenty large enough.
+    uint8_t dest[128]; // Only primitive fields, should be plenty large enough.
     auto encoded_size = static_cast<uint32_t>(hdr.ByteSizeLong());
-    bool ok = hdr.SerializeToArray(dest, sizeof(dest));
-    assert(ok); // TODO
+    assert(encoded_size <= sizeof(dest));
+    [[maybe_unused]] bool ok = hdr.SerializeWithCachedSizesToArray(dest);
+    assert(ok);
     buf.putInt(encoded_size);
-    buf.putBytes(dest, encoded_size);
+    buf.putBytes(reinterpret_cast<const char*>(dest), encoded_size);
 }
 
 void write_response_header(vespalib::GrowableByteBuffer& buf, const api::StorageReply& reply) {
@@ -115,11 +116,12 @@ void write_response_header(vespalib::GrowableByteBuffer& buf, const api::Storage
     hdr.set_message_id(reply.getMsgId());
     hdr.set_priority(reply.getPriority());
 
-    std::string encoded; // TODO wrap in zero copy buffers!
-    bool ok = hdr.SerializeToString(&encoded);
-    assert(ok); // TODO
-    buf.putInt(static_cast<uint32_t>(encoded.size()));
-    buf.putBytes(encoded.data(), static_cast<uint32_t>(encoded.size()));
+    const auto header_size = hdr.ByteSizeLong();
+    buf.putInt(static_cast<uint32_t>(header_size));
+
+    auto* dest_buf = reinterpret_cast<uint8_t*>(buf.allocate(header_size));
+    [[maybe_unused]] bool ok = hdr.SerializeWithCachedSizesToArray(dest_buf);
+    assert(ok);
 }
 
 void decode_request_header(document::ByteBuffer& buf, protobuf::RequestHeader& hdr) {
@@ -163,10 +165,10 @@ public:
 
     void encode() {
         assert(_proto_obj != nullptr);
-        std::string encoded; // TODO wrap in zero copy buffers!
-        bool ok = _proto_obj->SerializeToString(&encoded);
-        assert(ok); // TODO
-        _out_buf.putBytes(encoded.data(), encoded.size());
+        const auto sz = _proto_obj->ByteSizeLong();
+        auto* buf = reinterpret_cast<uint8_t*>(_out_buf.allocate(sz));
+        [[maybe_unused]] bool ok = _proto_obj->SerializeWithCachedSizesToArray(buf);
+        assert(ok);
         _proto_obj = nullptr;
     }
 protected: