SERVER-20609 do not heap allocate Message

16 files changed, 55 insertions, 60 deletions

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;
 };