SERVER-20609 do not heap allocate Message

35 files changed, 163 insertions, 177 deletions

diff --git a/src/mongo/client/dbclient.cpp b/src/mongo/client/dbclient.cpp
index 7e0196d7ff5..6f7407355da 100644
--- a/src/mongo/client/dbclient.cpp
+++ b/src/mongo/client/dbclient.cpp
@@ -309,7 +309,7 @@ rpc::UniqueReply DBClientWithCommands::runCommandWithMetadata(StringData databas
     requestBuilder->setCommandArgs(commandArgs);
     auto requestMsg = requestBuilder->done();
 
-    auto replyMsg = stdx::make_unique<Message>();
+    Message replyMsg;
 
     // We always want to throw if there was a network error, we do it here
     // instead of passing 'true' for the 'assertOk' parameter so we can construct a
@@ -318,14 +318,14 @@ rpc::UniqueReply DBClientWithCommands::runCommandWithMetadata(StringData databas
             str::stream() << "network error while attempting to run "
                           << "command '" << command << "' "
                           << "on host '" << host << "' ",
-            call(*requestMsg, *replyMsg, false, &host));
+            call(requestMsg, replyMsg, false, &host));
 
-    auto commandReply = rpc::makeReply(replyMsg.get());
+    auto commandReply = rpc::makeReply(&replyMsg);
 
     uassert(ErrorCodes::RPCProtocolNegotiationFailed,
             str::stream() << "Mismatched RPC protocols - request was '"
-                          << opToString(requestMsg->operation()) << "' '"
-                          << " but reply was '" << opToString(replyMsg->operation()) << "' ",
+                          << opToString(requestMsg.operation()) << "' '"
+                          << " but reply was '" << opToString(replyMsg.operation()) << "' ",
             requestBuilder->getProtocol() == commandReply->getProtocol());
 
     if (ErrorCodes::SendStaleConfig ==
diff --git a/src/mongo/client/dbclientcursor.cpp b/src/mongo/client/dbclientcursor.cpp
index b5100b98bcc..00eb939da30 100644
--- a/src/mongo/client/dbclientcursor.cpp
+++ b/src/mongo/client/dbclientcursor.cpp
@@ -59,10 +59,10 @@ namespace {
  * This code is mostly duplicated from DBClientWithCommands::runCommand. It may not
  * be worth de-duplicating as this codepath will eventually be removed anyway.
  */
-std::unique_ptr<Message> assembleCommandRequest(DBClientWithCommands* cli,
-                                                StringData database,
-                                                int legacyQueryOptions,
-                                                BSONObj legacyQuery) {
+Message assembleCommandRequest(DBClientWithCommands* cli,
+                               StringData database,
+                               int legacyQueryOptions,
+                               BSONObj legacyQuery) {
     // TODO: Rewrite this to a common utility shared between this and DBClientMultiCommand.
 
     // Can be an OP_COMMAND or OP_QUERY message.
@@ -117,8 +117,7 @@ void DBClientCursor::_assembleInit(Message& toSend) {
         bool hasValidFlagsForCommand = !(opts & mongo::QueryOption_Exhaust);
 
         if (_isCommand && hasValidNToReturnForCommand && hasValidFlagsForCommand) {
-            toSend =
-                std::move(*assembleCommandRequest(_client, nsToDatabaseSubstring(ns), opts, query));
+            toSend = assembleCommandRequest(_client, nsToDatabaseSubstring(ns), opts, query);
             return;
         }
         assembleQueryRequest(ns, query, nextBatchSize(), nToSkip, fieldsToReturn, opts, toSend);
@@ -137,12 +136,12 @@ bool DBClientCursor::init() {
     Message toSend;
     _assembleInit(toSend);
     verify(_client);
-    if (!_client->call(toSend, *batch.m, false, &_originalHost)) {
+    if (!_client->call(toSend, batch.m, false, &_originalHost)) {
         // log msg temp?
         log() << "DBClientCursor::init call() failed" << endl;
         return false;
     }
-    if (batch.m->empty()) {
+    if (batch.m.empty()) {
         // log msg temp?
         log() << "DBClientCursor::init message from call() was empty" << endl;
         return false;
@@ -161,13 +160,13 @@ void DBClientCursor::initLazy(bool isRetry) {
 }
 
 bool DBClientCursor::initLazyFinish(bool& retry) {
-    bool recvd = _client->recv(*batch.m);
+    bool recvd = _client->recv(batch.m);
 
     // If we get a bad response, return false
-    if (!recvd || batch.m->empty()) {
+    if (!recvd || batch.m.empty()) {
         if (!recvd)
             log() << "DBClientCursor::init lazy say() failed" << endl;
-        if (batch.m->empty())
+        if (batch.m.empty())
             log() << "DBClientCursor::init message from say() was empty" << endl;
 
         _client->checkResponse(NULL, -1, &retry, &_lazyHost);
@@ -184,7 +183,7 @@ bool DBClientCursor::initCommand() {
     BSONObj res;
 
     bool ok = _client->runCommand(nsGetDB(ns), query, res, opts);
-    replyToQuery(0, *batch.m, res);
+    replyToQuery(0, batch.m, res);
     dataReceived();
 
     return ok;
@@ -205,16 +204,16 @@ void DBClientCursor::requestMore() {
 
     Message toSend;
     toSend.setData(dbGetMore, b.buf(), b.len());
-    unique_ptr<Message> response(new Message());
+    Message response;
 
     if (_client) {
-        _client->call(toSend, *response);
+        _client->call(toSend, response);
         this->batch.m = std::move(response);
         dataReceived();
     } else {
         verify(_scopedHost.size());
         ScopedDbConnection conn(_scopedHost);
-        conn->call(toSend, *response);
+        conn->call(toSend, response);
         _client = conn.get();
         ON_BLOCK_EXIT([this] { _client = nullptr; });
         this->batch.m = std::move(response);
@@ -227,9 +226,9 @@ void DBClientCursor::requestMore() {
 void DBClientCursor::exhaustReceiveMore() {
     verify(cursorId && batch.pos == batch.nReturned);
     verify(!haveLimit);
-    unique_ptr<Message> response(new Message());
+    Message response;
     verify(_client);
-    if (!_client->recv(*response)) {
+    if (!_client->recv(response)) {
         uasserted(16465, "recv failed while exhausting cursor");
     }
     batch.m = std::move(response);
@@ -237,13 +236,13 @@ void DBClientCursor::exhaustReceiveMore() {
 }
 
 void DBClientCursor::commandDataReceived() {
-    int op = batch.m->operation();
+    int op = batch.m.operation();
     invariant(op == opReply || op == dbCommandReply);
 
     batch.nReturned = 1;
     batch.pos = 0;
 
-    auto commandReply = rpc::makeReply(batch.m.get());
+    auto commandReply = rpc::makeReply(&batch.m);
 
     auto commandStatus = getStatusFromCommandResult(commandReply->getCommandReply());
 
@@ -264,11 +263,11 @@ void DBClientCursor::commandDataReceived() {
     if (op == dbCommandReply) {
         // Need to take ownership here as we destroy the underlying message.
         BSONObj reply = commandReply->getCommandReply().getOwned();
-        batch.m = stdx::make_unique<Message>();
-        replyToQuery(0, *batch.m, reply);
+        batch.m.reset();
+        replyToQuery(0, batch.m, reply);
     }
 
-    QueryResult::View qr = batch.m->singleData().view2ptr();
+    QueryResult::View qr = batch.m.singleData().view2ptr();
     batch.data = qr.data();
 }
 
@@ -279,7 +278,7 @@ void DBClientCursor::dataReceived(bool& retry, string& host) {
         return;
     }
 
-    QueryResult::View qr = batch.m->singleData().view2ptr();
+    QueryResult::View qr = batch.m.singleData().view2ptr();
     resultFlags = qr.getResultFlags();
 
     if (qr.getResultFlags() & ResultFlag_ErrSet) {
diff --git a/src/mongo/client/dbclientcursor.h b/src/mongo/client/dbclientcursor.h
index 2dede943b4b..a085d90dbd9 100644
--- a/src/mongo/client/dbclientcursor.h
+++ b/src/mongo/client/dbclientcursor.h
@@ -191,7 +191,7 @@ public:
     }
 
     Message* getMessage() {
-        return batch.m.get();
+        return &batch.m;
     }
 
     /**
@@ -215,13 +215,13 @@ public:
     class Batch {
         MONGO_DISALLOW_COPYING(Batch);
         friend class DBClientCursor;
-        std::unique_ptr<Message> m;
-        int nReturned;
-        int pos;
-        const char* data;
+        Message m;
+        int nReturned{0};
+        int pos{0};
+        const char* data{nullptr};
 
     public:
-        Batch() : m(new Message()), nReturned(), pos(), data() {}
+        Batch() = default;
     };
 
     /**
diff --git a/src/mongo/client/scoped_db_conn_test.cpp b/src/mongo/client/scoped_db_conn_test.cpp
index b032ed2651c..bbc805dfbf2 100644
--- a/src/mongo/client/scoped_db_conn_test.cpp
+++ b/src/mongo/client/scoped_db_conn_test.cpp
@@ -119,10 +119,12 @@ public:
             commandResponse.append("minWireVersion", WireVersion::RELEASE_2_4_AND_BEFORE);
         }
 
-        port->reply(m,
-                    *reply->setMetadata(rpc::makeEmptyMetadata())
-                         .setCommandReply(commandResponse.done())
-                         .done());
+
+        auto response = reply->setMetadata(rpc::makeEmptyMetadata())
+                            .setCommandReply(commandResponse.done())
+                            .done();
+
+        port->reply(m, response);
     }
 
 } dummyHandler;
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index 4f2d3676f19..ce1a9bfc4a3 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -173,10 +173,10 @@ public:
                 // results after the response reaches the client
             }
 
-            if (dbresponse.response) {
-                port->reply(m, *dbresponse.response, dbresponse.responseTo);
+            if (!dbresponse.response.empty()) {
+                port->reply(m, dbresponse.response, dbresponse.responseTo);
                 if (dbresponse.exhaustNS.size() > 0) {
-                    MsgData::View header = dbresponse.response->header();
+                    MsgData::View header = dbresponse.response.header();
                     QueryResult::View qr = header.view2ptr();
                     long long cursorid = qr.getCursorId();
                     if (cursorid) {
diff --git a/src/mongo/db/dbdirectclient.cpp b/src/mongo/db/dbdirectclient.cpp
index 244669481c5..519cade63ad 100644
--- a/src/mongo/db/dbdirectclient.cpp
+++ b/src/mongo/db/dbdirectclient.cpp
@@ -121,11 +121,11 @@ bool DBDirectClient::call(Message& toSend, Message& response, bool assertOk, str
     DbResponse dbResponse;
     CurOp curOp(_txn);
     assembleResponse(_txn, toSend, dbResponse, dummyHost);
-    verify(dbResponse.response);
+    verify(!dbResponse.response.empty());
 
     // can get rid of this if we make response handling smarter
-    dbResponse.response->concat();
-    response = std::move(*dbResponse.response);
+    dbResponse.response.concat();
+    response = std::move(dbResponse.response);
 
     return true;
 }
diff --git a/src/mongo/db/dbmessage.cpp b/src/mongo/db/dbmessage.cpp
index eb50ecb063a..5750542eb26 100644
--- a/src/mongo/db/dbmessage.cpp
+++ b/src/mongo/db/dbmessage.cpp
@@ -201,9 +201,9 @@ void replyToQuery(int queryResultFlags,
 }
 
 void replyToQuery(int queryResultFlags, Message& m, DbResponse& dbresponse, BSONObj obj) {
-    Message* resp = new Message();
-    replyToQuery(queryResultFlags, *resp, obj);
-    dbresponse.response = resp;
+    Message resp;
+    replyToQuery(queryResultFlags, resp, obj);
+    dbresponse.response = std::move(resp);
     dbresponse.responseTo = m.header().getId();
 }
 
diff --git a/src/mongo/db/dbmessage.h b/src/mongo/db/dbmessage.h
index aa74fd59ffb..2f0c6b6645b 100644
--- a/src/mongo/db/dbmessage.h
+++ b/src/mongo/db/dbmessage.h
@@ -312,16 +312,11 @@ public:
  * A response to a DbMessage.
  */
 struct DbResponse {
-    Message* response;
+    Message response;
     MSGID responseTo;
     std::string exhaustNS; /* points to ns if exhaust mode. 0=normal mode*/
-    DbResponse(Message* r, MSGID rt) : response(r), responseTo(rt) {}
-    DbResponse() {
-        response = 0;
-    }
-    ~DbResponse() {
-        delete response;
-    }
+    DbResponse(Message r, MSGID rt) : response(std::move(r)), responseTo(rt) {}
+    DbResponse() = default;
 };
 
 void replyToQuery(int queryResultFlags,
diff --git a/src/mongo/db/dbwebserver.cpp b/src/mongo/db/dbwebserver.cpp
index 1ad6e54a236..b60e1dd77c3 100644
--- a/src/mongo/db/dbwebserver.cpp
+++ b/src/mongo/db/dbwebserver.cpp
@@ -280,13 +280,13 @@ public:
             .setCommandArgs(cmdObj);
 
         auto cmdRequestMsg = requestBuilder.done();
-        rpc::CommandRequest cmdRequest{cmdRequestMsg.get()};
+        rpc::CommandRequest cmdRequest{&cmdRequestMsg};
         rpc::CommandReplyBuilder cmdReplyBuilder{};
 
         Command::execCommand(txn, c, cmdRequest, &cmdReplyBuilder);
 
         auto cmdReplyMsg = cmdReplyBuilder.done();
-        rpc::CommandReply cmdReply{cmdReplyMsg.get()};
+        rpc::CommandReply cmdReply{&cmdReplyMsg};
 
         responseCode = 200;
 
diff --git a/src/mongo/db/ftdc/SConscript b/src/mongo/db/ftdc/SConscript
index 1527dbdd5f9..b2ff0255bfb 100644
--- a/src/mongo/db/ftdc/SConscript
+++ b/src/mongo/db/ftdc/SConscript
@@ -63,4 +63,3 @@ env.CppUnitTest(
         'ftdc',
     ],
 )
-
diff --git a/src/mongo/db/instance.cpp b/src/mongo/db/instance.cpp
index 59e3bebb214..e752ae92fa6 100644
--- a/src/mongo/db/instance.cpp
+++ b/src/mongo/db/instance.cpp
@@ -260,9 +260,9 @@ static void receivedCommand(OperationContext* txn,
 
     auto response = builder.done();
 
-    op->debug().responseLength = response->header().dataLen();
+    op->debug().responseLength = response.header().dataLen();
 
-    dbResponse.response = response.release();
+    dbResponse.response = std::move(response);
     dbResponse.responseTo = responseTo;
 }
 
@@ -301,9 +301,9 @@ void receivedRpc(OperationContext* txn, Client& client, DbResponse& dbResponse,
 
     auto response = replyBuilder.done();
 
-    curOp->debug().responseLength = response->header().dataLen();
+    curOp->debug().responseLength = response.header().dataLen();
 
-    dbResponse.response = response.release();
+    dbResponse.response = std::move(response);
     dbResponse.responseTo = responseTo;
 }
 
@@ -378,7 +378,6 @@ static void receivedQuery(OperationContext* txn,
 
     DbMessage d(m);
     QueryMessage q(d);
-    unique_ptr<Message> resp(new Message());
 
     CurOp& op = *CurOp::get(txn);
 
@@ -388,16 +387,13 @@ static void receivedQuery(OperationContext* txn,
         audit::logQueryAuthzCheck(client, nss, q.query, status.code());
         uassertStatusOK(status);
 
-        dbResponse.exhaustNS = runQuery(txn, q, nss, *resp);
-        verify(!resp->empty());
+        dbResponse.exhaustNS = runQuery(txn, q, nss, dbResponse.response);
     } catch (const AssertionException& exception) {
-        resp.reset(new Message());
-        generateLegacyQueryErrorResponse(&exception, q, &op, resp.get());
+        dbResponse.response.reset();
+        generateLegacyQueryErrorResponse(&exception, q, &op, &dbResponse.response);
     }
 
-    op.debug().responseLength = resp->header().dataLen();
-
-    dbResponse.response = resp.release();
+    op.debug().responseLength = dbResponse.response.header().dataLen();
     dbResponse.responseTo = responseTo;
 }
 
@@ -536,13 +532,11 @@ void assembleResponse(OperationContext* txn,
             log(LogComponent::kQuery) << curTimeMillis64() % 10000
                                       << " long msg received, len:" << len << endl;
 
-        Message* resp = new Message();
         if (strcmp("end", p) == 0)
-            resp->setData(opReply, "dbMsg end no longer supported");
+            dbresponse.response.setData(opReply, "dbMsg end no longer supported");
         else
-            resp->setData(opReply, "i am fine - dbMsg deprecated");
+            dbresponse.response.setData(opReply, "i am fine - dbMsg deprecated");
 
-        dbresponse.response = resp;
         dbresponse.responseTo = m.header().getId();
     } else {
         try {
@@ -923,17 +917,15 @@ bool receivedGetMore(OperationContext* txn, DbResponse& dbresponse, Message& m,
         curop.debug().exceptionInfo = e.getInfo();
 
         replyToQuery(ResultFlag_ErrSet, m, dbresponse, errObj);
-        curop.debug().responseLength = dbresponse.response->header().dataLen();
+        curop.debug().responseLength = dbresponse.response.header().dataLen();
         curop.debug().nreturned = 1;
         return false;
     }
 
-    Message* resp = new Message();
-    resp->setData(msgdata.view2ptr(), true);
-    curop.debug().responseLength = resp->header().dataLen();
+    dbresponse.response.setData(msgdata.view2ptr(), true);
+    curop.debug().responseLength = dbresponse.response.header().dataLen();
     curop.debug().nreturned = msgdata.getNReturned();
 
-    dbresponse.response = resp;
     dbresponse.responseTo = m.header().getId();
 
     if (exhaust) {
@@ -1106,11 +1098,11 @@ static void insertSystemIndexes(OperationContext* txn, DbMessage& d, CurOp& curO
                                      .setMetadata(rpc::makeEmptyMetadata())
                                      .setCommandArgs(cmdObj)
                                      .done();
-            rpc::LegacyRequest cmdRequest{cmdRequestMsg.get()};
+            rpc::LegacyRequest cmdRequest{&cmdRequestMsg};
             rpc::LegacyReplyBuilder cmdReplyBuilder{};
             Command::execCommand(txn, createIndexesCmd, cmdRequest, &cmdReplyBuilder);
             auto cmdReplyMsg = cmdReplyBuilder.done();
-            rpc::LegacyReply cmdReply{cmdReplyMsg.get()};
+            rpc::LegacyReply cmdReply{&cmdReplyMsg};
             uassertStatusOK(Command::getStatusFromCommandResult(cmdReply.getCommandReply()));
         } catch (const DBException& ex) {
             LastError::get(txn->getClient()).setLastError(ex.getCode(), ex.getInfo().msg);
diff --git a/src/mongo/dbtests/mock/mock_remote_db_server.cpp b/src/mongo/dbtests/mock/mock_remote_db_server.cpp
index 963677012f6..d4949e171d6 100644
--- a/src/mongo/dbtests/mock/mock_remote_db_server.cpp
+++ b/src/mongo/dbtests/mock/mock_remote_db_server.cpp
@@ -172,7 +172,7 @@ rpc::UniqueReply MockRemoteDBServer::runCommandWithMetadata(MockRemoteDBServer::
                        .setMetadata(rpc::makeEmptyMetadata())
                        .setCommandReply(reply)
                        .done();
-    auto replyView = stdx::make_unique<rpc::CommandReply>(message.get());
+    auto replyView = stdx::make_unique<rpc::CommandReply>(&message);
     return rpc::UniqueReply(std::move(message), std::move(replyView));
 }
 
diff --git a/src/mongo/executor/async_mock_stream_factory.cpp b/src/mongo/executor/async_mock_stream_factory.cpp
index 3132bab52b7..341615bdbce 100644
--- a/src/mongo/executor/async_mock_stream_factory.cpp
+++ b/src/mongo/executor/async_mock_stream_factory.cpp
@@ -308,22 +308,22 @@ void AsyncMockStreamFactory::MockStream::simulateServer(
     replyBuilder->setCommandReply(resp.data);
 
     auto replyMsg = replyBuilder->done();
-    replyMsg->header().setResponseTo(messageId);
+    replyMsg.header().setResponseTo(messageId);
 
     {
         // The first read will be for the header.
         ReadEvent read{this};
-        auto hdrBytes = reinterpret_cast<const uint8_t*>(replyMsg->header().view2ptr());
+        auto hdrBytes = reinterpret_cast<const uint8_t*>(replyMsg.header().view2ptr());
         pushRead({hdrBytes, hdrBytes + sizeof(MSGHEADER::Value)});
     }
 
     {
         // The second read will be for the message data.
         ReadEvent read{this};
-        auto dataBytes = reinterpret_cast<const uint8_t*>(replyMsg->buf());
+        auto dataBytes = reinterpret_cast<const uint8_t*>(replyMsg.buf());
         auto pastHeader = dataBytes;
         std::advance(pastHeader, sizeof(MSGHEADER::Value));
-        pushRead({pastHeader, dataBytes + static_cast<std::size_t>(replyMsg->size())});
+        pushRead({pastHeader, dataBytes + static_cast<std::size_t>(replyMsg.size())});
     }
 
     if (ex) {
diff --git a/src/mongo/executor/connection_pool_asio.cpp b/src/mongo/executor/connection_pool_asio.cpp
index ea494194053..d63ef0488cc 100644
--- a/src/mongo/executor/connection_pool_asio.cpp
+++ b/src/mongo/executor/connection_pool_asio.cpp
@@ -146,7 +146,7 @@ Message ASIOConnection::makeIsMasterRequest(ASIOConnection* conn) {
     requestBuilder.setMetadata(rpc::makeEmptyMetadata());
     requestBuilder.setCommandArgs(BSON("isMaster" << 1));
 
-    return std::move(*(requestBuilder.done()));
+    return requestBuilder.done();
 }
 
 void ASIOConnection::setTimeout(Milliseconds timeout, TimeoutCallback cb) {
diff --git a/src/mongo/executor/network_interface_asio_auth.cpp b/src/mongo/executor/network_interface_asio_auth.cpp
index 9202fbaf51e..a44f2cd2ca1 100644
--- a/src/mongo/executor/network_interface_asio_auth.cpp
+++ b/src/mongo/executor/network_interface_asio_auth.cpp
@@ -59,7 +59,7 @@ void NetworkInterfaceASIO::_runIsMaster(AsyncOp* op) {
 
     // Set current command to ismaster request and run
     auto beginStatus = op->beginCommand(
-        std::move(*(requestBuilder.done())), AsyncCommand::CommandType::kRPC, op->request().target);
+        requestBuilder.done(), AsyncCommand::CommandType::kRPC, op->request().target);
     if (!beginStatus.isOK()) {
         return _completeOperation(op, beginStatus);
     }
diff --git a/src/mongo/executor/network_interface_asio_operation.cpp b/src/mongo/executor/network_interface_asio_operation.cpp
index e890c7c4e5f..dbce0eb9c73 100644
--- a/src/mongo/executor/network_interface_asio_operation.cpp
+++ b/src/mongo/executor/network_interface_asio_operation.cpp
@@ -53,9 +53,9 @@ using asio::ip::tcp;
 namespace {
 
 // Metadata listener can be nullptr.
-StatusWith<std::unique_ptr<Message>> messageFromRequest(const RemoteCommandRequest& request,
-                                                        rpc::Protocol protocol,
-                                                        rpc::EgressMetadataHook* metadataHook) {
+StatusWith<Message> messageFromRequest(const RemoteCommandRequest& request,
+                                       rpc::Protocol protocol,
+                                       rpc::EgressMetadataHook* metadataHook) {
     BSONObj query = request.cmdObj;
     auto requestBuilder = rpc::makeRequestBuilder(protocol);
 
@@ -179,7 +179,7 @@ Status NetworkInterfaceASIO::AsyncOp::beginCommand(const RemoteCommandRequest& r
             return newCommand.getStatus();
         }
         return beginCommand(
-            std::move(*newCommand.getValue()), AsyncCommand::CommandType::kRPC, request.target);
+            std::move(newCommand.getValue()), AsyncCommand::CommandType::kRPC, request.target);
     } else if (isFindCmd) {
         auto downconvertedFind = downconvertFindCommandRequest(request);
         if (!downconvertedFind.isOK()) {
diff --git a/src/mongo/executor/network_interface_asio_test.cpp b/src/mongo/executor/network_interface_asio_test.cpp
index ceabe364287..baed65f122e 100644
--- a/src/mongo/executor/network_interface_asio_test.cpp
+++ b/src/mongo/executor/network_interface_asio_test.cpp
@@ -424,24 +424,24 @@ public:
         replyBuilder->setCommandReply(BSON("hello!" << 1));
 
         auto message = replyBuilder->done();
-        message->header().setResponseTo(messageId);
+        message.header().setResponseTo(messageId);
 
-        auto actualSize = message->header().getLen();
+        auto actualSize = message.header().getLen();
 
         // Allow caller to mess with the Message
-        hook(message->header());
+        hook(message.header());
 
         {
             // Load the header
             ReadEvent read{stream};
-            auto headerBytes = reinterpret_cast<const uint8_t*>(message->header().view2ptr());
+            auto headerBytes = reinterpret_cast<const uint8_t*>(message.header().view2ptr());
             stream->pushRead({headerBytes, headerBytes + sizeof(MSGHEADER::Value)});
         }
 
         if (loadBody) {
             // Load the body if we need to
             ReadEvent read{stream};
-            auto dataBytes = reinterpret_cast<const uint8_t*>(message->buf());
+            auto dataBytes = reinterpret_cast<const uint8_t*>(message.buf());
             auto body = dataBytes;
             std::advance(body, sizeof(MSGHEADER::Value));
             stream->pushRead({body, dataBytes + static_cast<std::size_t>(actualSize)});
diff --git a/src/mongo/rpc/command_reply_builder.cpp b/src/mongo/rpc/command_reply_builder.cpp
index 8bc50590333..65744efa49f 100644
--- a/src/mongo/rpc/command_reply_builder.cpp
+++ b/src/mongo/rpc/command_reply_builder.cpp
@@ -40,10 +40,9 @@
 namespace mongo {
 namespace rpc {
 
-CommandReplyBuilder::CommandReplyBuilder() : CommandReplyBuilder(stdx::make_unique<Message>()) {}
+CommandReplyBuilder::CommandReplyBuilder() : CommandReplyBuilder(Message{}) {}
 
-CommandReplyBuilder::CommandReplyBuilder(std::unique_ptr<Message> message)
-    : _message{std::move(message)} {
+CommandReplyBuilder::CommandReplyBuilder(Message&& message) : _message{std::move(message)} {
     _builder.skip(mongo::MsgData::MsgDataHeaderSize);
 }
 
@@ -105,17 +104,17 @@ void CommandReplyBuilder::reset() {
     }
     _builder.reset();
     _builder.skip(mongo::MsgData::MsgDataHeaderSize);
-    _message = stdx::make_unique<Message>();
+    _message.reset();
     _state = State::kMetadata;
 }
 
-std::unique_ptr<Message> CommandReplyBuilder::done() {
+Message CommandReplyBuilder::done() {
     invariant(_state == State::kOutputDocs);
     MsgData::View msg = _builder.buf();
     msg.setLen(_builder.len());
     msg.setOperation(dbCommandReply);
-    _builder.decouple();                      // release ownership from BufBuilder
-    _message->setData(msg.view2ptr(), true);  // transfer ownership to Message
+    _builder.decouple();                     // release ownership from BufBuilder
+    _message.setData(msg.view2ptr(), true);  // transfer ownership to Message
     _state = State::kDone;
     return std::move(_message);
 }
diff --git a/src/mongo/rpc/command_reply_builder.h b/src/mongo/rpc/command_reply_builder.h
index 92c567f64a6..b91b335fcdc 100644
--- a/src/mongo/rpc/command_reply_builder.h
+++ b/src/mongo/rpc/command_reply_builder.h
@@ -54,7 +54,7 @@ public:
      * Constructs an OP_COMMANDREPLY in an existing buffer. Ownership of the buffer
      * will be transfered to the CommandReplyBuilder.
      */
-    CommandReplyBuilder(std::unique_ptr<Message> message);
+    CommandReplyBuilder(Message&& message);
 
     CommandReplyBuilder& setMetadata(const BSONObj& metadata) final;
     CommandReplyBuilder& setRawCommandReply(const BSONObj& commandReply) final;
@@ -73,7 +73,7 @@ public:
      * The behavior of calling any methods on the object is subsequently
      * undefined.
      */
-    std::unique_ptr<Message> done() final;
+    Message done() final;
 
     std::size_t availableBytes() const final;
 
@@ -86,7 +86,7 @@ private:
 
     // Default values are all empty.
     BufBuilder _builder{};
-    std::unique_ptr<Message> _message;
+    Message _message;
     State _state{State::kMetadata};
 };
 
diff --git a/src/mongo/rpc/command_reply_test.cpp b/src/mongo/rpc/command_reply_test.cpp
index 4ace31f46d5..b5d372b42be 100644
--- a/src/mongo/rpc/command_reply_test.cpp
+++ b/src/mongo/rpc/command_reply_test.cpp
@@ -51,12 +51,10 @@ using std::end;
 class ReplyTest : public mongo::unittest::Test {
 protected:
     std::vector<char> _cmdData{};
-    // using unique ptr so we can destroy and replace easily
-    // since message does not have operator= or swap defined...
-    std::unique_ptr<Message> _message{};
+    Message _message{};
 
     virtual void setUp() override {
-        _message = stdx::make_unique<Message>();
+        _message.reset();
     }
 
     virtual void tearDown() override {
@@ -73,8 +71,8 @@ protected:
 
     const Message* buildMessage() {
         _cmdData.shrink_to_fit();
-        _message->setData(dbCommandReply, _cmdData.data(), _cmdData.size());
-        return _message.get();
+        _message.setData(dbCommandReply, _cmdData.data(), _cmdData.size());
+        return &_message;
     }
 };
 
diff --git a/src/mongo/rpc/command_request_builder.cpp b/src/mongo/rpc/command_request_builder.cpp
index 25f67c11e7f..60a013d218f 100644
--- a/src/mongo/rpc/command_request_builder.cpp
+++ b/src/mongo/rpc/command_request_builder.cpp
@@ -39,13 +39,11 @@
 namespace mongo {
 namespace rpc {
 
-CommandRequestBuilder::CommandRequestBuilder()
-    : CommandRequestBuilder(stdx::make_unique<Message>()) {}
+CommandRequestBuilder::CommandRequestBuilder() : CommandRequestBuilder(Message()) {}
 
 CommandRequestBuilder::~CommandRequestBuilder() {}
 
-CommandRequestBuilder::CommandRequestBuilder(std::unique_ptr<Message> message)
-    : _message{std::move(message)} {
+CommandRequestBuilder::CommandRequestBuilder(Message&& message) : _message{std::move(message)} {
     _builder.skip(mongo::MsgData::MsgDataHeaderSize);  // Leave room for message header.
 }
 
@@ -98,13 +96,13 @@ Protocol CommandRequestBuilder::getProtocol() const {
     return rpc::Protocol::kOpCommandV1;
 }
 
-std::unique_ptr<Message> CommandRequestBuilder::done() {
+Message CommandRequestBuilder::done() {
     invariant(_state == State::kInputDocs);
     MsgData::View msg = _builder.buf();
     msg.setLen(_builder.len());
     msg.setOperation(dbCommand);
-    _builder.decouple();                      // release ownership from BufBuilder.
-    _message->setData(msg.view2ptr(), true);  // transfer ownership to Message.
+    _builder.decouple();                     // release ownership from BufBuilder.
+    _message.setData(msg.view2ptr(), true);  // transfer ownership to Message.
     _state = State::kDone;
     return std::move(_message);
 }
diff --git a/src/mongo/rpc/command_request_builder.h b/src/mongo/rpc/command_request_builder.h
index cf00e3f9652..50b3f69fab2 100644
--- a/src/mongo/rpc/command_request_builder.h
+++ b/src/mongo/rpc/command_request_builder.h
@@ -56,7 +56,7 @@ public:
      * Construct an OP_COMMAND in an existing buffer. Ownership of the buffer will be
      * transfered to the CommandRequestBuilder.
      */
-    CommandRequestBuilder(std::unique_ptr<Message> message);
+    CommandRequestBuilder(Message&& message);
 
     CommandRequestBuilder& setDatabase(StringData database) final;
 
@@ -79,11 +79,11 @@ public:
      * The behavior of calling any methods on the object is subsequently
      * undefined.
      */
-    std::unique_ptr<Message> done() final;
+    Message done() final;
 
 private:
     BufBuilder _builder{};
-    std::unique_ptr<Message> _message;
+    Message _message;
 
     State _state{State::kDatabase};
 };
diff --git a/src/mongo/rpc/command_request_builder_test.cpp b/src/mongo/rpc/command_request_builder_test.cpp
index cdfbc9d01a9..5972a41752f 100644
--- a/src/mongo/rpc/command_request_builder_test.cpp
+++ b/src/mongo/rpc/command_request_builder_test.cpp
@@ -78,7 +78,7 @@ TEST(RequestBuilder, RoundTrip) {
                    .addInputDocs(inputDocRange)
                    .done();
 
-    rpc::CommandRequest parsed(msg.get());
+    rpc::CommandRequest parsed(&msg);
 
     ASSERT_EQUALS(parsed.getDatabase(), databaseName);
     ASSERT_EQUALS(parsed.getCommandName(), commandName);
diff --git a/src/mongo/rpc/command_request_test.cpp b/src/mongo/rpc/command_request_test.cpp
index 8f681655b56..18dbc2edc66 100644
--- a/src/mongo/rpc/command_request_test.cpp
+++ b/src/mongo/rpc/command_request_test.cpp
@@ -115,7 +115,7 @@ TEST(CommandRequest, InvalidNSThrows) {
     crb.setMetadata(BSONObj());
     crb.setCommandArgs(BSON("ping" << 1));
     auto msg = crb.done();
-    ASSERT_THROWS(rpc::CommandRequest{msg.get()}, AssertionException);
+    ASSERT_THROWS(rpc::CommandRequest{&msg}, AssertionException);
 }
 
 }  // namespace
diff --git a/src/mongo/rpc/legacy_reply_builder.cpp b/src/mongo/rpc/legacy_reply_builder.cpp
index 592e3588b43..e4830c10f2a 100644
--- a/src/mongo/rpc/legacy_reply_builder.cpp
+++ b/src/mongo/rpc/legacy_reply_builder.cpp
@@ -65,9 +65,9 @@ bool isEmptyCommandReply(const BSONObj& bson) {
 const char LegacyReplyBuilder::kCursorTag[] = "cursor";
 const char LegacyReplyBuilder::kFirstBatchTag[] = "firstBatch";
 
-LegacyReplyBuilder::LegacyReplyBuilder() : LegacyReplyBuilder(stdx::make_unique<Message>()) {}
+LegacyReplyBuilder::LegacyReplyBuilder() : LegacyReplyBuilder(Message()) {}
 
-LegacyReplyBuilder::LegacyReplyBuilder(std::unique_ptr<Message> message)
+LegacyReplyBuilder::LegacyReplyBuilder(Message&& message)
     : _currentLength{kReservedSize}, _message{std::move(message)} {}
 
 LegacyReplyBuilder::~LegacyReplyBuilder() {}
@@ -164,14 +164,14 @@ void LegacyReplyBuilder::reset() {
     if (_state == State::kMetadata) {
         return;
     }
-    _message = stdx::make_unique<Message>();
+    _message.reset();
     _currentLength = kReservedSize;
     _currentIndex = 0U;
     _state = State::kMetadata;
 }
 
 
-std::unique_ptr<Message> LegacyReplyBuilder::done() {
+Message LegacyReplyBuilder::done() {
     invariant(_state == State::kOutputDocs);
 
     BSONObj reply = uassertStatusOK(rpc::downconvertReplyMetadata(_commandReply, _metadata));
@@ -221,7 +221,7 @@ std::unique_ptr<Message> LegacyReplyBuilder::done() {
     qr.setStartingFrom(0);
     qr.setNReturned(1);
 
-    _message->setData(qr.view2ptr(), true);
+    _message.setData(qr.view2ptr(), true);
     bufBuilder.decouple();
 
     _state = State::kDone;
diff --git a/src/mongo/rpc/legacy_reply_builder.h b/src/mongo/rpc/legacy_reply_builder.h
index 957265f0611..814fb9096e1 100644
--- a/src/mongo/rpc/legacy_reply_builder.h
+++ b/src/mongo/rpc/legacy_reply_builder.h
@@ -35,6 +35,7 @@
 #include "mongo/rpc/document_range.h"
 #include "mongo/rpc/protocol.h"
 #include "mongo/rpc/reply_builder_interface.h"
+#include "mongo/util/net/message.h"
 
 namespace mongo {
 namespace rpc {
@@ -45,7 +46,7 @@ public:
     static const char kFirstBatchTag[];
 
     LegacyReplyBuilder();
-    LegacyReplyBuilder(std::unique_ptr<Message>);
+    LegacyReplyBuilder(Message&&);
     ~LegacyReplyBuilder() final;
 
     LegacyReplyBuilder& setMetadata(const BSONObj& metadata) final;
@@ -58,7 +59,7 @@ public:
 
     void reset() final;
 
-    std::unique_ptr<Message> done() final;
+    Message done() final;
 
     Protocol getProtocol() const final;
 
@@ -78,7 +79,7 @@ private:
     BSONObj _commandReply{};
     std::size_t _currentLength;
     std::size_t _currentIndex = 0U;
-    std::unique_ptr<Message> _message;
+    Message _message;
     BSONObj _metadata{};
     std::vector<BSONObj> _outputDocs{};
     State _state{State::kMetadata};
diff --git a/src/mongo/rpc/legacy_request_builder.cpp b/src/mongo/rpc/legacy_request_builder.cpp
index db333dc4c6a..33f66a4811f 100644
--- a/src/mongo/rpc/legacy_request_builder.cpp
+++ b/src/mongo/rpc/legacy_request_builder.cpp
@@ -42,12 +42,11 @@
 namespace mongo {
 namespace rpc {
 
-LegacyRequestBuilder::LegacyRequestBuilder() : LegacyRequestBuilder(stdx::make_unique<Message>()) {}
+LegacyRequestBuilder::LegacyRequestBuilder() : LegacyRequestBuilder(Message()) {}
 
 LegacyRequestBuilder::~LegacyRequestBuilder() {}
 
-LegacyRequestBuilder::LegacyRequestBuilder(std::unique_ptr<Message> message)
-    : _message{std::move(message)} {
+LegacyRequestBuilder::LegacyRequestBuilder(Message&& message) : _message{std::move(message)} {
     _builder.skip(mongo::MsgData::MsgDataHeaderSize);
 }
 
@@ -111,13 +110,13 @@ Protocol LegacyRequestBuilder::getProtocol() const {
     return rpc::Protocol::kOpQuery;
 }
 
-std::unique_ptr<Message> LegacyRequestBuilder::done() {
+Message LegacyRequestBuilder::done() {
     invariant(_state == State::kInputDocs);
     MsgData::View msg = _builder.buf();
     msg.setLen(_builder.len());
     msg.setOperation(dbQuery);
-    _builder.decouple();                      // release ownership from BufBuilder
-    _message->setData(msg.view2ptr(), true);  // transfer ownership to Message
+    _builder.decouple();                     // release ownership from BufBuilder
+    _message.setData(msg.view2ptr(), true);  // transfer ownership to Message
     _state = State::kDone;
     return std::move(_message);
 }
diff --git a/src/mongo/rpc/legacy_request_builder.h b/src/mongo/rpc/legacy_request_builder.h
index 0d44c47a513..d20011cc443 100644
--- a/src/mongo/rpc/legacy_request_builder.h
+++ b/src/mongo/rpc/legacy_request_builder.h
@@ -44,7 +44,7 @@ public:
     LegacyRequestBuilder();
     ~LegacyRequestBuilder() final;
 
-    LegacyRequestBuilder(std::unique_ptr<Message>);
+    LegacyRequestBuilder(Message&&);
 
     LegacyRequestBuilder& setDatabase(StringData database) final;
     LegacyRequestBuilder& setCommandName(StringData commandName) final;
@@ -58,10 +58,10 @@ public:
 
     Protocol getProtocol() const final;
 
-    std::unique_ptr<Message> done() final;
+    Message done() final;
 
 private:
-    std::unique_ptr<Message> _message;
+    Message _message;
     BufBuilder _builder{};
 
     // we need to stash this as we need commandArgs to
diff --git a/src/mongo/rpc/legacy_request_test.cpp b/src/mongo/rpc/legacy_request_test.cpp
index caadc74e3e8..1413a139d71 100644
--- a/src/mongo/rpc/legacy_request_test.cpp
+++ b/src/mongo/rpc/legacy_request_test.cpp
@@ -46,7 +46,7 @@ TEST(LegacyRequest, InvalidNSThrows) {
     crb.setMetadata(BSONObj());
     crb.setCommandArgs(BSON("ping" << 1));
     auto msg = crb.done();
-    ASSERT_THROWS(rpc::LegacyRequest{msg.get()}, AssertionException);
+    ASSERT_THROWS(rpc::LegacyRequest{&msg}, AssertionException);
 }
 
 }  // namespace
diff --git a/src/mongo/rpc/reply_builder_interface.h b/src/mongo/rpc/reply_builder_interface.h
index c02511be567..5f3f2621746 100644
--- a/src/mongo/rpc/reply_builder_interface.h
+++ b/src/mongo/rpc/reply_builder_interface.h
@@ -131,7 +131,7 @@ public:
      * Writes data then transfers ownership of the message to the caller. The behavior of
      * calling any methods on the builder is subsequently undefined.
      */
-    virtual std::unique_ptr<Message> done() = 0;
+    virtual Message done() = 0;
 
 protected:
     ReplyBuilderInterface() = default;
diff --git a/src/mongo/rpc/reply_builder_test.cpp b/src/mongo/rpc/reply_builder_test.cpp
index ad50b810989..9ae3544aba5 100644
--- a/src/mongo/rpc/reply_builder_test.cpp
+++ b/src/mongo/rpc/reply_builder_test.cpp
@@ -96,7 +96,7 @@ TEST(CommandReplyBuilder, MemAccess) {
     replyBuilder.setCommandReply(commandReply);
     auto msg = replyBuilder.done();
 
-    rpc::CommandReply parsed(msg.get());
+    rpc::CommandReply parsed(&msg);
 
     ASSERT_EQUALS(parsed.getMetadata(), metadata);
     ASSERT_EQUALS(parsed.getCommandReply(), commandReply);
@@ -110,7 +110,7 @@ TEST(LegacyReplyBuilder, MemAccess) {
     replyBuilder.setCommandReply(commandReply);
     auto msg = replyBuilder.done();
 
-    rpc::LegacyReply parsed(msg.get());
+    rpc::LegacyReply parsed(&msg);
 
     ASSERT_EQUALS(parsed.getMetadata(), metadata);
     ASSERT_EQUALS(parsed.getCommandReply(), commandReply);
@@ -164,7 +164,7 @@ void testRoundTrip(rpc::ReplyBuilderInterface& replyBuilder) {
 
     auto msg = replyBuilder.done();
 
-    T parsed(msg.get());
+    T parsed(&msg);
 
     ASSERT_EQUALS(parsed.getMetadata(), metadata);
     ASSERT_TRUE(parsed.getOutputDocs() == outputDocRange);
@@ -207,10 +207,10 @@ TEST(LegacyReplyBuilderSpaceTest, DocSize) {
     replyBuilder0.setCommandReply(commandReply);
     auto msg0 = replyBuilder0.done();
 
-    QueryResult::View qr0 = msg0->singleData().view2ptr();
+    QueryResult::View qr0 = msg0.singleData().view2ptr();
     auto dataLen0 = static_cast<std::size_t>(qr0.msgdata().dataLen());
 
-    QueryResult::View qr = msg->singleData().view2ptr();
+    QueryResult::View qr = msg.singleData().view2ptr();
     auto dataLen = static_cast<std::size_t>(qr.msgdata().dataLen());
 
     // below tests the array space estimates
@@ -276,7 +276,7 @@ TEST_F(CommandReplyBuilderSpaceTest, MaxDocSize1) {
         availSpace = replyBuilder.availableBytes();
     }
     auto msg = replyBuilder.done();
-    auto sizeUInt = static_cast<std::size_t>(msg->size());
+    auto sizeUInt = static_cast<std::size_t>(msg.size());
 
     ASSERT_EQUALS(sizeUInt, mongo::MaxMessageSizeBytes);
 }
@@ -304,7 +304,7 @@ TEST_F(CommandReplyBuilderSpaceTest, MaxDocSize2) {
         availSpace = replyBuilder.availableBytes();
     }
     auto msg = replyBuilder.done();
-    auto sizeUInt = static_cast<std::size_t>(msg->size());
+    auto sizeUInt = static_cast<std::size_t>(msg.size());
 
     ASSERT_EQUALS(sizeUInt, mongo::MaxMessageSizeBytes);
 }
@@ -338,7 +338,7 @@ TEST_F(CommandReplyBuilderSpaceTest, MaxDocSize3) {
 
     auto msg = replyBuilder.done();
 
-    auto sizeUInt = static_cast<std::size_t>(msg->size());
+    auto sizeUInt = static_cast<std::size_t>(msg.size());
 
     ASSERT_EQUALS(sizeUInt, mongo::MaxMessageSizeBytes);
 }
diff --git a/src/mongo/rpc/request_builder_interface.h b/src/mongo/rpc/request_builder_interface.h
index f27c7e3e10d..2325863dd0f 100644
--- a/src/mongo/rpc/request_builder_interface.h
+++ b/src/mongo/rpc/request_builder_interface.h
@@ -108,7 +108,7 @@ public:
      * The behavior of calling any methods on the object is subsequently
      * undefined.
      */
-    virtual std::unique_ptr<Message> done() = 0;
+    virtual Message done() = 0;
 
 protected:
     RequestBuilderInterface() = default;
diff --git a/src/mongo/rpc/unique_message.h b/src/mongo/rpc/unique_message.h
index a763a82ec25..6b470b3f9dd 100644
--- a/src/mongo/rpc/unique_message.h
+++ b/src/mongo/rpc/unique_message.h
@@ -34,9 +34,9 @@
 #include "mongo/base/disallow_copying.h"
 #include "mongo/rpc/reply_interface.h"
 #include "mongo/rpc/request_interface.h"
+#include "mongo/util/net/message.h"
 
 namespace mongo {
-class Message;
 namespace rpc {
 
 /**
@@ -48,7 +48,7 @@ class UniqueMessage {
     MONGO_DISALLOW_COPYING(UniqueMessage);
 
 public:
-    UniqueMessage(std::unique_ptr<Message> message, std::unique_ptr<MessageViewType> view)
+    UniqueMessage(Message&& message, std::unique_ptr<MessageViewType> view)
         : _message{std::move(message)}, _view{std::move(view)} {}
 
 #if defined(_MSC_VER) && _MSC_VER < 1900
@@ -77,13 +77,13 @@ public:
      * Releases ownership of the underlying message. The result of calling any other methods
      * on the object afterward is undefined.
      */
-    std::unique_ptr<Message> releaseMessage() {
+    Message releaseMessage() {
         _view.reset();
         return std::move(_message);
     }
 
 private:
-    std::unique_ptr<Message> _message;
+    Message _message;
     std::unique_ptr<MessageViewType> _view;
 };
 
diff --git a/src/mongo/s/client/dbclient_multi_command.cpp b/src/mongo/s/client/dbclient_multi_command.cpp
index b3801104f0d..41097339346 100644
--- a/src/mongo/s/client/dbclient_multi_command.cpp
+++ b/src/mongo/s/client/dbclient_multi_command.cpp
@@ -96,7 +96,8 @@ static void sayAsCmd(DBClientBase* conn, StringData dbName, const BSONObj& cmdOb
     requestBuilder->setMetadata(metadataBob.done());
     requestBuilder->setCommandArgs(upconvertedCmd);
     // Send our command
-    conn->say(*requestBuilder->done());
+    auto requestMsg = requestBuilder->done();
+    conn->say(requestMsg);
 }
 
 // THROWS
diff --git a/src/mongo/util/net/message.h b/src/mongo/util/net/message.h
index 4518127f8ff..da5433a7f20 100644
--- a/src/mongo/util/net/message.h
+++ b/src/mongo/util/net/message.h
@@ -342,13 +342,15 @@ class Message {
 public:
     // we assume here that a vector with initial size 0 does no allocation (0 is the default, but
     // wanted to make it explicit).
-    Message() : _buf(0), _data(0), _freeIt(false) {}
-    Message(void* data, bool freeIt) : _buf(0), _data(0), _freeIt(false) {
-        _setData(reinterpret_cast<char*>(data), freeIt);
-    };
-    Message(Message&& r) : _buf(0), _data(0), _freeIt(false) {
-        *this = std::move(r);
+    Message() = default;
+
+    Message(void* data, bool freeIt) : _buf(reinterpret_cast<char*>(data)), _freeIt(freeIt) {}
+
+    Message(Message&& r) : _buf(r._buf), _data(std::move(r._data)), _freeIt(r._freeIt) {
+        r._buf = nullptr;
+        r._freeIt = false;
     }
+
     ~Message() {
         reset();
     }
@@ -420,30 +422,31 @@ public:
         if (&r == this)
             return *this;
 
-        verify(empty());  // This means that our _data must be empty() when we swap below.
-        verify(r._freeIt);
-        _buf = r._buf;
-        r._buf = 0;
-        if (r._data.size() > 0) {
-            _data.swap(r._data);
+        if (!empty()) {
+            reset();
         }
+
+        _buf = r._buf;
+        _data = std::move(r._data);
+        _freeIt = r._freeIt;
+
+        r._buf = nullptr;
         r._freeIt = false;
-        _freeIt = true;
         return *this;
     }
 
     void reset() {
         if (_freeIt) {
             if (_buf) {
-                free(_buf);
+                std::free(_buf);
             }
             for (std::vector<std::pair<char*, int>>::const_iterator i = _data.begin();
                  i != _data.end();
                  ++i) {
-                free(i->first);
+                std::free(i->first);
             }
         }
-        _buf = 0;
+        _buf = nullptr;
         _data.clear();
         _freeIt = false;
     }
@@ -505,12 +508,12 @@ private:
         _buf = d;
     }
     // if just one buffer, keep it in _buf, otherwise keep a sequence of buffers in _data
-    char* _buf;
+    char* _buf{nullptr};
     // byte buffer(s) - the first must contain at least a full MsgData unless using _buf for storage
     // instead
     typedef std::vector<std::pair<char*, int>> MsgVec;
-    MsgVec _data;
-    bool _freeIt;
+    MsgVec _data{};
+    bool _freeIt{false};
 };