SERVER-29564 BSONObjBuilder can now be seeded with a BSONObj prefix

This will avoid copying whenever it is safe.

7 files changed, 14 insertions, 18 deletions

diff --git a/src/mongo/rpc/command_request.cpp b/src/mongo/rpc/command_request.cpp
index a796f6f8a19..067abeef636 100644
--- a/src/mongo/rpc/command_request.cpp
+++ b/src/mongo/rpc/command_request.cpp
@@ -105,8 +105,7 @@ ParsedOpCommand ParsedOpCommand::parse(const Message& message) {
 OpMsgRequest opMsgRequestFromCommandRequest(const Message& message) {
     auto parsed = ParsedOpCommand::parse(message);
 
-    BSONObjBuilder bodyBuilder;
-    bodyBuilder.appendElements(parsed.body);
+    BSONObjBuilder bodyBuilder(std::move(parsed.body));
 
     // OP_COMMAND is only used when communicating with 3.4 nodes and they serialize their metadata
     // fields differently. We do all up-conversion here so that the rest of the code only has to
diff --git a/src/mongo/rpc/legacy_reply_builder.cpp b/src/mongo/rpc/legacy_reply_builder.cpp
index 5fb373d12c8..340d892472f 100644
--- a/src/mongo/rpc/legacy_reply_builder.cpp
+++ b/src/mongo/rpc/legacy_reply_builder.cpp
@@ -52,7 +52,7 @@ LegacyReplyBuilder::LegacyReplyBuilder(Message&& message) : _message{std::move(m
 LegacyReplyBuilder::~LegacyReplyBuilder() {}
 
 LegacyReplyBuilder& LegacyReplyBuilder::setCommandReply(Status nonOKStatus,
-                                                        const BSONObj& extraErrorInfo) {
+                                                        BSONObj extraErrorInfo) {
     invariant(_state == State::kCommandReply);
     if (nonOKStatus == ErrorCodes::SendStaleConfig) {
         _staleConfigError = true;
@@ -66,7 +66,7 @@ LegacyReplyBuilder& LegacyReplyBuilder::setCommandReply(Status nonOKStatus,
         setRawCommandReply(err.done());
     } else {
         // All other errors proceed through the normal path, which also handles state transitions.
-        ReplyBuilderInterface::setCommandReply(std::move(nonOKStatus), extraErrorInfo);
+        ReplyBuilderInterface::setCommandReply(std::move(nonOKStatus), std::move(extraErrorInfo));
     }
     return *this;
 }
diff --git a/src/mongo/rpc/legacy_reply_builder.h b/src/mongo/rpc/legacy_reply_builder.h
index beb7806147c..d72fdc6b93b 100644
--- a/src/mongo/rpc/legacy_reply_builder.h
+++ b/src/mongo/rpc/legacy_reply_builder.h
@@ -49,7 +49,7 @@ public:
     ~LegacyReplyBuilder() final;
 
     // Override of setCommandReply specifically used to handle SendStaleConfigException.
-    LegacyReplyBuilder& setCommandReply(Status nonOKStatus, const BSONObj& extraErrorInfo) final;
+    LegacyReplyBuilder& setCommandReply(Status nonOKStatus, BSONObj extraErrorInfo) final;
     LegacyReplyBuilder& setRawCommandReply(const BSONObj& commandReply) final;
 
     BSONObjBuilder getInPlaceReplyBuilder(std::size_t) final;
diff --git a/src/mongo/rpc/legacy_request.cpp b/src/mongo/rpc/legacy_request.cpp
index 9d5beae3af2..8247c7d3923 100644
--- a/src/mongo/rpc/legacy_request.cpp
+++ b/src/mongo/rpc/legacy_request.cpp
@@ -55,7 +55,7 @@ OpMsgRequest opMsgRequestFromLegacyRequest(const Message& message) {
     auto bodyAndMetadata = rpc::upconvertRequestMetadata(qm.query, qm.queryOptions);
 
     return OpMsgRequest::fromDBAndBody(
-        ns.db(), std::get<0>(bodyAndMetadata), std::get<1>(bodyAndMetadata));
+        ns.db(), std::move(std::get<0>(bodyAndMetadata)), std::get<1>(bodyAndMetadata));
 }
 
 }  // namespace rpc
diff --git a/src/mongo/rpc/metadata.cpp b/src/mongo/rpc/metadata.cpp
index bf3aab6c8e4..715532f453d 100644
--- a/src/mongo/rpc/metadata.cpp
+++ b/src/mongo/rpc/metadata.cpp
@@ -164,8 +164,7 @@ CommandAndMetadata upconvertRequestMetadata(BSONObj legacyCmdObj, int queryFlags
 LegacyCommandAndFlags downconvertRequestMetadata(BSONObj cmdObj, BSONObj metadata) {
     int legacyQueryFlags = 0;
     if (auto logicalTime = metadata[LogicalTimeMetadata::fieldName()]) {
-        BSONObjBuilder logicalTimeCommandBob;
-        logicalTimeCommandBob.appendElements(cmdObj);
+        BSONObjBuilder logicalTimeCommandBob(std::move(cmdObj));
         logicalTimeCommandBob.append(logicalTime);
         cmdObj = logicalTimeCommandBob.obj();
     }
diff --git a/src/mongo/rpc/reply_builder_interface.cpp b/src/mongo/rpc/reply_builder_interface.cpp
index 34a99cd4176..99fe2edcb1e 100644
--- a/src/mongo/rpc/reply_builder_interface.cpp
+++ b/src/mongo/rpc/reply_builder_interface.cpp
@@ -48,14 +48,13 @@ const char kErrorField[] = "errmsg";
 
 // similar to appendCommandStatus (duplicating logic here to avoid cyclic library
 // dependency)
-BSONObj augmentReplyWithStatus(const Status& status, const BSONObj& reply) {
+BSONObj augmentReplyWithStatus(const Status& status, BSONObj reply) {
     auto okField = reply.getField(kOKField);
     if (!okField.eoo() && okField.trueValue()) {
         return reply;
     }
 
-    BSONObjBuilder bob;
-    bob.appendElements(reply);
+    BSONObjBuilder bob(std::move(reply));
     if (okField.eoo()) {
         bob.append(kOKField, status.isOK() ? 1.0 : 0.0);
     }
@@ -63,11 +62,11 @@ BSONObj augmentReplyWithStatus(const Status& status, const BSONObj& reply) {
         return bob.obj();
     }
 
-    if (!reply.hasField(kErrorField)) {
+    if (!bob.asTempObj().hasField(kErrorField)) {
         bob.append(kErrorField, status.reason());
     }
 
-    if (!reply.hasField(kCodeField)) {
+    if (!bob.asTempObj().hasField(kCodeField)) {
         bob.append(kCodeField, status.code());
         bob.append(kCodeNameField, ErrorCodes::errorString(status.code()));
     }
@@ -78,13 +77,13 @@ BSONObj augmentReplyWithStatus(const Status& status, const BSONObj& reply) {
 
 ReplyBuilderInterface& ReplyBuilderInterface::setCommandReply(StatusWith<BSONObj> commandReply) {
     auto reply = commandReply.isOK() ? std::move(commandReply.getValue()) : BSONObj();
-    return setRawCommandReply(augmentReplyWithStatus(commandReply.getStatus(), reply));
+    return setRawCommandReply(augmentReplyWithStatus(commandReply.getStatus(), std::move(reply)));
 }
 
 ReplyBuilderInterface& ReplyBuilderInterface::setCommandReply(Status nonOKStatus,
-                                                              const BSONObj& extraErrorInfo) {
+                                                              BSONObj extraErrorInfo) {
     invariant(!nonOKStatus.isOK());
-    return setRawCommandReply(augmentReplyWithStatus(nonOKStatus, extraErrorInfo));
+    return setRawCommandReply(augmentReplyWithStatus(nonOKStatus, std::move(extraErrorInfo)));
 }
 
 }  // namespace rpc
diff --git a/src/mongo/rpc/reply_builder_interface.h b/src/mongo/rpc/reply_builder_interface.h
index b2631bfaf0e..a157f41167e 100644
--- a/src/mongo/rpc/reply_builder_interface.h
+++ b/src/mongo/rpc/reply_builder_interface.h
@@ -84,8 +84,7 @@ public:
      * interfacing with legacy code that adds additional data to a failed command reply and
      * its use is discouraged in new code.
      */
-    virtual ReplyBuilderInterface& setCommandReply(Status nonOKStatus,
-                                                   const BSONObj& extraErrorInfo);
+    virtual ReplyBuilderInterface& setCommandReply(Status nonOKStatus, BSONObj extraErrorInfo);
 
     /**
      * Gets the protocol used to serialize this reply. This should be used for validity checks