SERVER-19464 Add a way to explicitly kill a DBClientCursor before destruction

(cherry picked from commit 0476dec3ae310f768ae7fd31418a4c8aa7c24506)

2 files changed, 19 insertions, 0 deletions

diff --git a/src/mongo/client/dbclientcursor.cpp b/src/mongo/client/dbclientcursor.cpp
index fa8e5c7d14b..2e0b0a0fa4d 100644
--- a/src/mongo/client/dbclientcursor.cpp
+++ b/src/mongo/client/dbclientcursor.cpp
@@ -325,6 +325,10 @@ namespace mongo {
     }
 
     DBClientCursor::~DBClientCursor() {
+        kill();
+    }
+
+    void DBClientCursor::kill() {
         if (!this)
             return;
 
@@ -362,6 +366,9 @@ namespace mongo {
         }
 
         );
+
+        // Mark this cursor as dead since we can't do any getMores.
+        cursorId = 0;
     }
 
 
diff --git a/src/mongo/client/dbclientcursor.h b/src/mongo/client/dbclientcursor.h
index 4ed29b0150a..810822f6a91 100644
--- a/src/mongo/client/dbclientcursor.h
+++ b/src/mongo/client/dbclientcursor.h
@@ -202,6 +202,18 @@ namespace mongo {
         void initLazy( bool isRetry = false );
         bool initLazyFinish( bool& retry );
 
+        /**
+         * Marks this object as dead and sends the KillCursors message to the server.
+         *
+         * Any errors that result from this are swallowed since this is typically performed as part
+         * of cleanup and a failure to kill the cursor should not result in a failure of the
+         * operation using the cursor.
+         *
+         * Killing an already killed or exhausted cursor does nothing, so it is safe to always call
+         * this if you want to ensure that a cursor is killed.
+         */
+        void kill();
+
         class Batch : boost::noncopyable {
             friend class DBClientCursor;
             auto_ptr<Message> m;