SERVER-19554 merge ReplSetMetadata and ReplicationMetadata

5 files changed, 124 insertions, 74 deletions

diff --git a/src/mongo/rpc/metadata.cpp b/src/mongo/rpc/metadata.cpp
index 74d511d5d4e..30b435e2872 100644
--- a/src/mongo/rpc/metadata.cpp
+++ b/src/mongo/rpc/metadata.cpp
@@ -39,8 +39,6 @@
 namespace mongo {
 namespace rpc {
 
-const char kReplicationMetadataFieldName[] = "$replData";
-
 BSONObj makeEmptyMetadata() {
     return BSONObj();
 }
diff --git a/src/mongo/rpc/metadata.h b/src/mongo/rpc/metadata.h
index 04cc1606d3e..c2160516d4c 100644
--- a/src/mongo/rpc/metadata.h
+++ b/src/mongo/rpc/metadata.h
@@ -57,8 +57,6 @@ class OperationContext;
  */
 namespace rpc {
 
-extern const char kReplicationMetadataFieldName[];
-
 /**
  * Returns an empty metadata object.
  */
diff --git a/src/mongo/rpc/metadata/repl_set_metadata.cpp b/src/mongo/rpc/metadata/repl_set_metadata.cpp
index d275dc833da..66780b50633 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata.cpp
+++ b/src/mongo/rpc/metadata/repl_set_metadata.cpp
@@ -28,6 +28,7 @@
 
 #include "mongo/rpc/metadata/repl_set_metadata.h"
 
+#include "mongo/bson/util/bson_check.h"
 #include "mongo/bson/util/bson_extract.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/rpc/metadata.h"
@@ -37,81 +38,88 @@ namespace rpc {
 
 using repl::OpTime;
 
+const char kReplSetMetadataFieldName[] = "$replData";
+
 namespace {
 
-const char kTermField[] = "term";
-const char kLastCommittedTSField[] = "lastOpCommittedTimestamp";
-const char kLastCommittedTermField[] = "lastOpCommittedTerm";
-const char kLastCommittedConfigVersionField[] = "configVersion";
-const char kLastCommittedPrimaryIndexField[] = "primaryIndex";
+const char kLastOpCommittedFieldName[] = "lastOpCommitted";
+const char kLastOpVisibleFieldName[] = "lastOpVisible";
+const char kConfigVersionFieldName[] = "configVersion";
+const char kPrimaryIndexFieldName[] = "primaryIndex";
+const char kTimestampFieldName[] = "ts";
+const char kTermFieldName[] = "term";
 
 }  // unnamed namespace
 
-ReplSetMetadata::ReplSetMetadata() = default;
-
 ReplSetMetadata::ReplSetMetadata(long long term,
                                  OpTime committedOpTime,
+                                 OpTime visibleOpTime,
                                  long long configVersion,
                                  int currentPrimaryIndex)
-    : _currentTerm(term),
-      _committedOpTime(std::move(committedOpTime)),
+    : _lastOpCommitted(std::move(committedOpTime)),
+      _lastOpVisible(std::move(visibleOpTime)),
+      _currentTerm(term),
       _configVersion(configVersion),
       _currentPrimaryIndex(currentPrimaryIndex) {}
 
-StatusWith<ReplSetMetadata> ReplSetMetadata::readFromMetadata(const BSONObj& doc) {
-    long long term = 0;
-    auto termStatus = bsonExtractIntegerField(doc, kTermField, &term);
-
-    if (!termStatus.isOK()) {
-        return termStatus;
-    }
-
-    Timestamp timestamp;
-    auto timestampStatus = bsonExtractTimestampField(doc, kLastCommittedTSField, &timestamp);
-
-    if (!timestampStatus.isOK()) {
-        return timestampStatus;
-    }
-
-    long long termNumber = 0;
-    auto commtedTermStatus = bsonExtractIntegerField(doc, kLastCommittedTermField, &termNumber);
-
-    if (!commtedTermStatus.isOK()) {
-        return commtedTermStatus;
-    }
-
-    long long configVersion = 0;
-    auto configVersionStatus =
-        bsonExtractIntegerField(doc, kLastCommittedConfigVersionField, &configVersion);
+StatusWith<ReplSetMetadata> ReplSetMetadata::readFromMetadata(const BSONObj& metadataObj) {
+    BSONElement replMetadataElement;
+
+    Status status = bsonExtractTypedField(
+        metadataObj, rpc::kReplSetMetadataFieldName, Object, &replMetadataElement);
+    if (!status.isOK())
+        return status;
+    BSONObj replMetadataObj = replMetadataElement.Obj();
+
+    long long configVersion;
+    status = bsonExtractIntegerField(replMetadataObj, kConfigVersionFieldName, &configVersion);
+    if (!status.isOK())
+        return status;
+
+    long long primaryIndex;
+    status = bsonExtractIntegerField(replMetadataObj, kPrimaryIndexFieldName, &primaryIndex);
+    if (!status.isOK())
+        return status;
+
+    long long term;
+    status = bsonExtractIntegerField(replMetadataObj, kTermFieldName, &term);
+    if (!status.isOK())
+        return status;
+
+    repl::OpTime lastOpCommitted;
+    status = bsonExtractOpTimeField(replMetadataObj, kLastOpCommittedFieldName, &lastOpCommitted);
+    if (!status.isOK())
+        return status;
+
+    repl::OpTime lastOpVisible;
+    status = bsonExtractOpTimeField(replMetadataObj, kLastOpVisibleFieldName, &lastOpVisible);
+    if (!status.isOK())
+        return status;
+
+    return ReplSetMetadata(term, lastOpCommitted, lastOpVisible, configVersion, primaryIndex);
+}
 
-    if (!configVersionStatus.isOK()) {
-        return configVersionStatus;
-    }
+Status ReplSetMetadata::writeToMetadata(BSONObjBuilder* builder) const {
+    BSONObjBuilder replMetadataBuilder(builder->subobjStart(kReplSetMetadataFieldName));
+    replMetadataBuilder.append(kTermFieldName, _currentTerm);
 
-    long long primaryIndex = 0;
-    auto primaryIndexStatus =
-        bsonExtractIntegerField(doc, kLastCommittedPrimaryIndexField, &primaryIndex);
+    BSONObjBuilder lastOpCommittedBuilder(
+        replMetadataBuilder.subobjStart(kLastOpCommittedFieldName));
+    lastOpCommittedBuilder.append(kTimestampFieldName, _lastOpCommitted.getTimestamp());
+    lastOpCommittedBuilder.append(kTermFieldName, _lastOpCommitted.getTerm());
+    lastOpCommittedBuilder.doneFast();
 
-    if (!primaryIndexStatus.isOK()) {
-        return primaryIndexStatus;
-    }
+    BSONObjBuilder lastOpVisibleBuilder(replMetadataBuilder.subobjStart(kLastOpVisibleFieldName));
+    lastOpVisibleBuilder.append(kTimestampFieldName, _lastOpVisible.getTimestamp());
+    lastOpVisibleBuilder.append(kTermFieldName, _lastOpVisible.getTerm());
+    lastOpVisibleBuilder.doneFast();
 
-    return ReplSetMetadata(term, OpTime(timestamp, termNumber), configVersion, primaryIndex);
-}
-
-Status ReplSetMetadata::writeToMetadata(BSONObjBuilder* builder) const {
-    builder->append(kTermField, _currentTerm);
-    builder->append(kLastCommittedTSField, _committedOpTime.getTimestamp());
-    builder->append(kLastCommittedTermField, _committedOpTime.getTerm());
-    builder->append(kLastCommittedConfigVersionField, _configVersion);
-    builder->append(kLastCommittedPrimaryIndexField, _currentPrimaryIndex);
+    replMetadataBuilder.append(kConfigVersionFieldName, _configVersion);
+    replMetadataBuilder.append(kPrimaryIndexFieldName, _currentPrimaryIndex);
+    replMetadataBuilder.doneFast();
 
     return Status::OK();
 }
 
-const OpTime& ReplSetMetadata::getLastCommittedOptime() const {
-    return _committedOpTime;
-}
-
 }  // namespace rpc
 }  // namespace mongo
diff --git a/src/mongo/rpc/metadata/repl_set_metadata.h b/src/mongo/rpc/metadata/repl_set_metadata.h
index bf34efb9dc7..c96cd14487a 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata.h
+++ b/src/mongo/rpc/metadata/repl_set_metadata.h
@@ -37,14 +37,17 @@ class BSONObjBuilder;
 
 namespace rpc {
 
+extern const char kReplSetMetadataFieldName[];
+
 /**
  * Represents the metadata information for $replData.
  */
 class ReplSetMetadata {
 public:
-    ReplSetMetadata();
+    ReplSetMetadata() = default;
     ReplSetMetadata(long long term,
                     repl::OpTime committedOpTime,
+                    repl::OpTime visibleOpTime,
                     long long configVersion,
                     int currentPrimaryIndex);
 
@@ -52,8 +55,8 @@ public:
      * format:
      * {
      *     term: 0,
-     *     lastOpCommittedTimestamp: 0,
-     *     lastOpCommittedTerm: 0,
+     *     lastOpCommitted: {ts: Timestamp(0, 0), term: 0}
+     *     lastOpVisible: {ts: Timestamp(0, 0), term: 0}
      *     configVersion: 0,
      *     primaryIndex: 0
      * }
@@ -61,13 +64,49 @@ public:
     static StatusWith<ReplSetMetadata> readFromMetadata(const BSONObj& doc);
     Status writeToMetadata(BSONObjBuilder* builder) const;
 
-    const repl::OpTime& getLastCommittedOptime() const;
+    /**
+     * Returns the OpTime of the most recent operation with which the client intereacted.
+     */
+    repl::OpTime getLastOpVisible() const {
+        return _lastOpVisible;
+    }
+
+    /**
+     * Returns the OpTime of the most recently committed op of which the sender was aware.
+     */
+    repl::OpTime getLastOpCommitted() const {
+        return _lastOpCommitted;
+    }
+
+    /**
+     * Returns the ReplSetConfig version number of the sender.
+     */
+    long long getConfigVersion() const {
+        return _configVersion;
+    }
+
+    /**
+     * Returns the index of the current primary from the perspective of the sender.
+     */
+    long long getPrimaryIndex() const {
+        return _currentPrimaryIndex;
+    }
+
+    /**
+     * Returns the current term from the perspective of the sender.
+     */
+    long long getTerm() const {
+        return _currentTerm;
+    }
 
 private:
-    long long _currentTerm = 0;
-    repl::OpTime _committedOpTime;
-    long long _configVersion = 0;
-    int _currentPrimaryIndex = 0;
+    repl::OpTime _lastOpCommitted =
+        repl::OpTime(Timestamp(0, 0), repl::OpTime::kProtocolVersionV0Term);
+    repl::OpTime _lastOpVisible =
+        repl::OpTime(Timestamp(0, 0), repl::OpTime::kProtocolVersionV0Term);
+    long long _currentTerm = -1;
+    long long _configVersion = -1;
+    int _currentPrimaryIndex = -1;
 };
 
 }  // namespace rpc
diff --git a/src/mongo/rpc/metadata/repl_set_metadata_test.cpp b/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
index 90e197978fc..82bff1f0209 100644
--- a/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
+++ b/src/mongo/rpc/metadata/repl_set_metadata_test.cpp
@@ -38,16 +38,22 @@ using repl::OpTime;
 
 TEST(ReplResponseMetadataTest, Roundtrip) {
     OpTime opTime(Timestamp(1234, 100), 5);
-    ReplSetMetadata metadata(3, opTime, 6, 12);
+    OpTime opTime2(Timestamp(7777, 100), 6);
+    ReplSetMetadata metadata(3, opTime, opTime2, 6, 12);
 
-    ASSERT_EQ(opTime, metadata.getLastCommittedOptime());
+    ASSERT_EQ(opTime, metadata.getLastOpCommitted());
+    ASSERT_EQ(opTime2, metadata.getLastOpVisible());
 
     BSONObjBuilder builder;
     metadata.writeToMetadata(&builder);
 
-    BSONObj expectedObj(BSON("term" << 3 << "lastOpCommittedTimestamp" << opTime.getTimestamp()
-                                    << "lastOpCommittedTerm" << opTime.getTerm() << "configVersion"
-                                    << 6 << "primaryIndex" << 12));
+    BSONObj expectedObj(
+        BSON(kReplSetMetadataFieldName
+             << BSON("term" << 3 << "lastOpCommitted"
+                            << BSON("ts" << opTime.getTimestamp() << "term" << opTime.getTerm())
+                            << "lastOpVisible"
+                            << BSON("ts" << opTime2.getTimestamp() << "term" << opTime2.getTerm())
+                            << "configVersion" << 6 << "primaryIndex" << 12)));
 
     BSONObj serializedObj = builder.obj();
     ASSERT_EQ(expectedObj, serializedObj);
@@ -56,7 +62,8 @@ TEST(ReplResponseMetadataTest, Roundtrip) {
     ASSERT_OK(cloneStatus.getStatus());
 
     const auto& clonedMetadata = cloneStatus.getValue();
-    ASSERT_EQ(opTime, clonedMetadata.getLastCommittedOptime());
+    ASSERT_EQ(opTime, clonedMetadata.getLastOpCommitted());
+    ASSERT_EQ(opTime2, clonedMetadata.getLastOpVisible());
 
     BSONObjBuilder clonedBuilder;
     clonedMetadata.writeToMetadata(&clonedBuilder);