1 files changed, 46 insertions, 1 deletions

diff --git a/src/mongo/db/write_concern_options.h b/src/mongo/db/write_concern_options.h
index 44c67b2938b..31b0f556c30 100644
--- a/src/mongo/db/write_concern_options.h
+++ b/src/mongo/db/write_concern_options.h
@@ -37,8 +37,11 @@ namespace mongo {
     struct WriteConcernOptions {
     public:
 
+        enum SyncMode { NONE, FSYNC, JOURNAL };
+
         static const int kNoTimeout = 0;
         static const int kNoWaiting = -1;
+
         static const BSONObj Default;
         static const BSONObj Acknowledged;
         static const BSONObj AllConfigs;
@@ -46,8 +49,43 @@ namespace mongo {
 
         WriteConcernOptions() { reset(); }
 
+        WriteConcernOptions(int numNodes,
+                            SyncMode sync,
+                            int timeout);
+
+        WriteConcernOptions(const std::string& mode,
+                            SyncMode sync,
+                            int timeout);
+
         Status parse( const BSONObj& obj );
 
+        /**
+         * Extracts the write concern settings from the BSONObj. The BSON object should have
+         * the format:
+         *
+         * {
+         *     ...
+         *     secondaryThrottle: <bool>, // optional
+         *     _secondaryThrottle: <bool>, // optional
+         *     writeConcern: <BSONObj> // optional
+         * }
+         *
+         * Note: secondaryThrottle takes precedence over _secondaryThrottle.
+         *
+         * Also sets output parameter rawWriteConcernObj if the writeCocnern field exists.
+         *
+         * Returns OK if the parse was successful. Also returns ErrorCodes::WriteConcernNotDefined
+         * when secondary throttle is true but write concern was not specified.
+         */
+        Status parseSecondaryThrottle(const BSONObj& doc,
+                                      BSONObj* rawWriteConcernObj);
+
+        /**
+         * Return true if the server needs to wait for other secondary nodes to satisfy this
+         * write concern setting. Errs on the false positive for non-empty wMode.
+         */
+        bool shouldWaitForOtherNodes() const;
+
         void reset() {
             syncMode = NONE;
             wNumNodes = 0;
@@ -55,11 +93,18 @@ namespace mongo {
             wTimeout = 0;
         }
 
-        enum SyncMode { NONE, FSYNC, JOURNAL } syncMode;
+        // Returns the BSON representation of this object.
+        // Warning: does not return the same object passed on the last parse() call.
+        BSONObj toBSON() const;
+
+        SyncMode syncMode;
 
+        // The w parameter for this write concern. The wMode represents the string format and
+        // takes precedence over the numeric format wNumNodes.
         int wNumNodes;
         std::string wMode;
 
+        // Timeout in milliseconds.
         int wTimeout;
     };