SERVER-14853 Port networking library to AAE

Use the alignment, aliasing and endian primitives in the networking
layer

24 files changed, 564 insertions, 330 deletions

diff --git a/src/mongo/client/dbclient_rs.cpp b/src/mongo/client/dbclient_rs.cpp
index 53e5baaa3ee..0f0e78a8c90 100644
--- a/src/mongo/client/dbclient_rs.cpp
+++ b/src/mongo/client/dbclient_rs.cpp
@@ -987,9 +987,9 @@ namespace {
             return false;
 
         if ( ns ) {
-            QueryResult * res = (QueryResult*)response.singleData();
-            if ( res->nReturned == 1 ) {
-                BSONObj x(res->data() );
+            QueryResult::View res = response.singleData().view2ptr();
+            if ( res.getNReturned() == 1 ) {
+                BSONObj x(res.data() );
                 if ( str::contains( ns , "$cmd" ) ) {
                     if ( isNotMasterErrorString( x["errmsg"] ) )
                         isntMaster();
diff --git a/src/mongo/client/dbclientcursor.cpp b/src/mongo/client/dbclientcursor.cpp
index c929a01a8e7..120c951e441 100644
--- a/src/mongo/client/dbclientcursor.cpp
+++ b/src/mongo/client/dbclientcursor.cpp
@@ -193,16 +193,16 @@ namespace mongo {
 
     void DBClientCursor::dataReceived( bool& retry, string& host ) {
 
-        QueryResult *qr = (QueryResult *) batch.m->singleData();
-        resultFlags = qr->resultFlags();
+        QueryResult::View qr = batch.m->singleData().view2ptr();
+        resultFlags = qr.getResultFlags();
 
-        if ( qr->resultFlags() & ResultFlag_ErrSet ) {
+        if ( qr.getResultFlags() & ResultFlag_ErrSet ) {
             wasError = true;
         }
 
-        if ( qr->resultFlags() & ResultFlag_CursorNotFound ) {
+        if ( qr.getResultFlags() & ResultFlag_CursorNotFound ) {
             // cursor id no longer valid at the server.
-            verify( qr->cursorId == 0 );
+            verify( qr.getCursorId() == 0 );
             cursorId = 0; // 0 indicates no longer valid (dead)
             if ( ! ( opts & QueryOption_CursorTailable ) )
                 throw UserException( 13127 , "getMore: cursor didn't exist on server, possible restart or timeout?" );
@@ -211,16 +211,16 @@ namespace mongo {
         if ( cursorId == 0 || ! ( opts & QueryOption_CursorTailable ) ) {
             // only set initially: we don't want to kill it on end of data
             // if it's a tailable cursor
-            cursorId = qr->cursorId;
+            cursorId = qr.getCursorId();
         }
 
-        batch.nReturned = qr->nReturned;
+        batch.nReturned = qr.getNReturned();
         batch.pos = 0;
-        batch.data = qr->data();
+        batch.data = qr.data();
 
         _client->checkResponse( batch.data, batch.nReturned, &retry, &host ); // watches for "not master"
 
-        if( qr->resultFlags() & ResultFlag_ShardConfigStale ) {
+        if( qr.getResultFlags() & ResultFlag_ShardConfigStale ) {
             BSONObj error;
             verify( peekError( &error ) );
             throw RecvStaleConfigException( (string)"stale config on lazy receive" + causedBy( getErrField( error ) ), error );
diff --git a/src/mongo/db/catalog/collection_cursor_cache.cpp b/src/mongo/db/catalog/collection_cursor_cache.cpp
index 2822117c9c7..ab9646eeb82 100644
--- a/src/mongo/db/catalog/collection_cursor_cache.cpp
+++ b/src/mongo/db/catalog/collection_cursor_cache.cpp
@@ -30,6 +30,7 @@
 
 #include "mongo/db/catalog/collection_cursor_cache.h"
 
+#include "mongo/base/data_cursor.h"
 #include "mongo/db/audit.h"
 #include "mongo/db/auth/authorization_session.h"
 #include "mongo/db/catalog/collection.h"
@@ -242,10 +243,11 @@ namespace mongo {
     }
 
     int CollectionCursorCache::eraseCursorGlobalIfAuthorized(OperationContext* txn, int n, 
-        const long long* ids) {
+        const char* _ids) {
+        ConstDataCursor ids(_ids);
         int numDeleted = 0;
         for ( int i = 0; i < n; i++ ) {
-            if ( eraseCursorGlobalIfAuthorized(txn, ids[i] ) )
+            if ( eraseCursorGlobalIfAuthorized(txn, ids.readLEAndAdvance<int64_t>()))
                 numDeleted++;
             if ( inShutdown() )
                 break;
diff --git a/src/mongo/db/catalog/collection_cursor_cache.h b/src/mongo/db/catalog/collection_cursor_cache.h
index 2015b7049d3..77c0df16557 100644
--- a/src/mongo/db/catalog/collection_cursor_cache.h
+++ b/src/mongo/db/catalog/collection_cursor_cache.h
@@ -111,7 +111,7 @@ namespace mongo {
         // ----------------------
 
         static int eraseCursorGlobalIfAuthorized(OperationContext* txn, int n, 
-            const long long* ids);
+            const char* ids);
         static bool eraseCursorGlobalIfAuthorized(OperationContext* txn, CursorId id);
 
         static bool eraseCursorGlobal(OperationContext* txn, CursorId id);
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index dd2b2b2ae82..531e8df648d 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -133,7 +133,7 @@ namespace mongo {
         }
     } mystartupdbcpp;
 
-    QueryResult* emptyMoreResult(long long);
+    QueryResult::View emptyMoreResult(long long);
 
 
     /* todo: make this a real test.  the stuff in dbtests/ seem to do all dbdirectclient which exhaust doesn't support yet. */
@@ -198,17 +198,17 @@ namespace mongo {
                 if ( dbresponse.response ) {
                     port->reply(m, *dbresponse.response, dbresponse.responseTo);
                     if( dbresponse.exhaustNS.size() > 0 ) {
-                        MsgData *header = dbresponse.response->header();
-                        QueryResult *qr = (QueryResult *) header;
-                        long long cursorid = qr->cursorId;
+                        MsgData::View header = dbresponse.response->header();
+                        QueryResult::View qr = header.view2ptr();
+                        long long cursorid = qr.getCursorId();
                         if( cursorid ) {
                             verify( dbresponse.exhaustNS.size() && dbresponse.exhaustNS[0] );
                             string ns = dbresponse.exhaustNS; // before reset() free's it...
                             m.reset();
                             BufBuilder b(512);
                             b.appendNum((int) 0 /*size set later in appendData()*/);
-                            b.appendNum(header->id);
-                            b.appendNum(header->responseTo);
+                            b.appendNum(header.getId());
+                            b.appendNum(header.getResponseTo());
                             b.appendNum((int) dbGetMore);
                             b.appendNum((int) 0);
                             b.appendStr(ns);
diff --git a/src/mongo/db/dbmessage.cpp b/src/mongo/db/dbmessage.cpp
index a3b06058547..1b0f3ae3a82 100644
--- a/src/mongo/db/dbmessage.cpp
+++ b/src/mongo/db/dbmessage.cpp
@@ -67,8 +67,8 @@ namespace mongo {
 
     DbMessage::DbMessage(const Message& msg) : _msg(msg), _nsStart(NULL), _mark(NULL), _nsLen(0) {
         // for received messages, Message has only one buffer
-        _theEnd = _msg.singleData()->_data + _msg.singleData()->dataLen();
-        _nextjsobj = _msg.singleData()->_data;
+        _theEnd = _msg.singleData().data() + _msg.singleData().dataLen();
+        _nextjsobj = _msg.singleData().data();
 
         _reserved = readAndAdvance<int>();
 
@@ -77,7 +77,7 @@ namespace mongo {
 
             // Limit = buffer size of message -
             //        (first int4 in message which is either flags or a zero constant)
-            size_t limit = _msg.singleData()->dataLen() - sizeof(int);
+            size_t limit = _msg.singleData().dataLen() - sizeof(int);
 
             _nsStart = _nextjsobj;
             _nsLen = strnlen(_nsStart, limit);
@@ -100,20 +100,20 @@ namespace mongo {
         const char* p = _nsStart + _nsLen + 1;
         checkRead<int>(p, 2);
 
-        return ((reinterpret_cast<const int*>(p)))[1];
+        return ConstDataView(p).readLE<int32_t>(sizeof(int32_t));
     }
 
     int DbMessage::pullInt() {
-        return readAndAdvance<int>();
+        return readAndAdvance<int32_t>();
     }
 
     long long DbMessage::pullInt64() {
-        return readAndAdvance<long long>();
+        return readAndAdvance<int64_t>();
     }
 
-    const long long* DbMessage::getArray(size_t count) const {
+    const char* DbMessage::getArray(size_t count) const {
         checkRead<long long>(_nextjsobj, count);
-        return reinterpret_cast<const long long*>(_nextjsobj);
+        return _nextjsobj;
     }
 
     BSONObj DbMessage::nextJsObj() {
@@ -158,7 +158,7 @@ namespace mongo {
     T DbMessage::read() const {
         checkRead<T>(_nextjsobj, 1);
 
-        return *(reinterpret_cast<const T*>(_nextjsobj));
+        return ConstDataView(_nextjsobj).readLE<T>();
     }
 
     template<typename T> T DbMessage::readAndAdvance() {
@@ -174,18 +174,18 @@ namespace mongo {
                       long long cursorId 
                       ) {
         BufBuilder b(32768);
-        b.skip(sizeof(QueryResult));
+        b.skip(sizeof(QueryResult::Value));
         b.appendBuf(data, size);
-        QueryResult *qr = (QueryResult *) b.buf();
-        qr->_resultFlags() = queryResultFlags;
-        qr->len = b.len();
-        qr->setOperation(opReply);
-        qr->cursorId = cursorId;
-        qr->startingFrom = startingFrom;
-        qr->nReturned = nReturned;
+        QueryResult::View qr = b.buf();
+        qr.setResultFlags(queryResultFlags);
+        qr.msgdata().setLen(b.len());
+        qr.msgdata().setOperation(opReply);
+        qr.setCursorId(cursorId);
+        qr.setStartingFrom(startingFrom);
+        qr.setNReturned(nReturned);
         b.decouple();
-        Message resp(qr, true);
-        p->reply(requestMsg, resp, requestMsg.header()->id);
+        Message resp(qr.view2ptr(), true);
+        p->reply(requestMsg, resp, requestMsg.header().getId());
     }
 
     void replyToQuery(int queryResultFlags,
@@ -200,26 +200,26 @@ namespace mongo {
         Message *resp = new Message();
         replyToQuery( queryResultFlags, *resp, obj );
         dbresponse.response = resp;
-        dbresponse.responseTo = m.header()->id;
+        dbresponse.responseTo = m.header().getId();
     }
 
     void replyToQuery( int queryResultFlags, Message& response, const BSONObj& resultObj ) {
         BufBuilder bufBuilder;
-        bufBuilder.skip( sizeof( QueryResult ));
+        bufBuilder.skip( sizeof( QueryResult::Value ));
         bufBuilder.appendBuf( reinterpret_cast< void *>(
                 const_cast< char* >( resultObj.objdata() )), resultObj.objsize() );
 
-        QueryResult* queryResult = reinterpret_cast< QueryResult* >( bufBuilder.buf() );
+        QueryResult::View queryResult = bufBuilder.buf();
         bufBuilder.decouple();
 
-        queryResult->_resultFlags() = queryResultFlags;
-        queryResult->len = bufBuilder.len();
-        queryResult->setOperation( opReply );
-        queryResult->cursorId = 0;
-        queryResult->startingFrom = 0;
-        queryResult->nReturned = 1;
+        queryResult.setResultFlags(queryResultFlags);
+        queryResult.msgdata().setLen(bufBuilder.len());
+        queryResult.msgdata().setOperation( opReply );
+        queryResult.setCursorId(0);
+        queryResult.setStartingFrom(0);
+        queryResult.setNReturned(1);
 
-        response.setData( queryResult, true ); // transport will free
+        response.setData( queryResult.view2ptr(), true ); // transport will free
     }
 
 }
diff --git a/src/mongo/db/dbmessage.h b/src/mongo/db/dbmessage.h
index 5131e2d30a2..1b15a58030e 100644
--- a/src/mongo/db/dbmessage.h
+++ b/src/mongo/db/dbmessage.h
@@ -91,31 +91,114 @@ namespace mongo {
    Note that the update field layout is very similar layout to Query.
 */
 
-
+    namespace QueryResult {
 #pragma pack(1)
-    struct QueryResult : public MsgData {
-        long long cursorId;
-        int startingFrom;
-        int nReturned;
-        const char *data() {
-            return (char *) (((int *)&nReturned)+1);
-        }
-        int resultFlags() {
-            return dataAsInt();
-        }
-        int& _resultFlags() {
-            return dataAsInt();
-        }
-        void setResultFlagsToOk() {
-            _resultFlags() = ResultFlag_AwaitCapable;
-        }
-        void initializeResultFlags() {
-            _resultFlags() = 0;   
-        }
-    };
-
+        /* see http://dochub.mongodb.org/core/mongowireprotocol
+        */
+        struct Layout {
+            MsgData::Layout msgdata;
+            int64_t cursorId;
+            int32_t startingFrom;
+            int32_t nReturned;
+        };
 #pragma pack()
 
+        class ConstView {
+        public:
+            ConstView(const char* storage) : _storage(storage) { }
+
+            const char* view2ptr() const {
+                return storage().view();
+            }
+
+            MsgData::ConstView msgdata() const {
+                return storage().view(offsetof(Layout, msgdata));
+            }
+
+            int64_t getCursorId() const {
+                return storage().readLE<int64_t>(offsetof(Layout, cursorId));
+            }
+
+            int32_t getStartingFrom() const {
+                return storage().readLE<int32_t>(offsetof(Layout, startingFrom));
+            }
+
+            int32_t getNReturned() const {
+                return storage().readLE<int32_t>(offsetof(Layout, nReturned));
+            }
+
+            const char* data() const {
+                return storage().view(sizeof(Layout));
+            }
+
+        protected:
+            const ConstDataView& storage() const {
+                return _storage;
+            }
+
+        private:
+            ConstDataView _storage;
+        };
+
+        class View : public ConstView {
+        public:
+            View(char* data) : ConstView(data) {}
+
+            using ConstView::view2ptr;
+            char* view2ptr() {
+                return storage().view();
+            }
+
+            using ConstView::msgdata;
+            MsgData::View msgdata() {
+                return storage().view(offsetof(Layout, msgdata));
+            }
+
+            void setCursorId(int64_t value) {
+                return storage().writeLE(value, offsetof(Layout, cursorId));
+            }
+
+            void setStartingFrom(int32_t value) {
+                return storage().writeLE(value, offsetof(Layout, startingFrom));
+            }
+
+            void setNReturned(int32_t value) {
+                return storage().writeLE(value, offsetof(Layout, nReturned));
+            }
+
+            int32_t getResultFlags() {
+                return DataView(msgdata().data()).readLE<int32_t>();
+            }
+
+            void setResultFlags(int32_t value) {
+                return DataView(msgdata().data()).writeLE(value);
+            }
+
+            void setResultFlagsToOk() {
+                setResultFlags(ResultFlag_AwaitCapable);
+            }
+
+            void initializeResultFlags() {
+                setResultFlags(0);
+            }
+
+        private:
+            DataView storage() const {
+                return const_cast<char*>(ConstView::view2ptr());
+            }
+        };
+
+        class Value : public EncodedValueStorage<Layout, ConstView, View> {
+        public:
+            Value() {
+                BOOST_STATIC_ASSERT(sizeof(Value) == sizeof(Layout));
+            }
+
+            Value(ZeroInitTag_t zit) : EncodedValueStorage<Layout, ConstView, View>(zit) {}
+        };
+
+    } // namespace QueryResult
+
     /* For the database/server protocol, these objects and functions encapsulate
        the various messages transmitted over the connection.
 
@@ -147,7 +230,7 @@ namespace mongo {
 
         int pullInt();
         long long pullInt64();
-        const long long* getArray(size_t count) const;
+        const char* getArray(size_t count) const;
 
         /* for insert and update msgs */
         bool moreJSObjs() const {
@@ -215,7 +298,7 @@ namespace mongo {
             if ( d.moreJSObjs() ) {
                 fields = d.nextJsObj();
             }
-            queryOptions = d.msg().header()->dataAsInt();
+            queryOptions = DataView(d.msg().header().data()).readLE<int32_t>();
         }
     };
 
diff --git a/src/mongo/db/instance.cpp b/src/mongo/db/instance.cpp
index 2835194ad04..30c69daca76 100644
--- a/src/mongo/db/instance.cpp
+++ b/src/mongo/db/instance.cpp
@@ -87,8 +87,17 @@ namespace mongo {
     MONGO_LOG_DEFAULT_COMPONENT_FILE(::mongo::logger::LogComponent::kCommands);
 
     // for diaglog
-    inline void opread(Message& m) { if( _diaglog.getLevel() & 2 ) _diaglog.readop((char *) m.singleData(), m.header()->len); }
-    inline void opwrite(Message& m) { if( _diaglog.getLevel() & 1 ) _diaglog.writeop((char *) m.singleData(), m.header()->len); }
+    inline void opread(Message& m) {
+        if (_diaglog.getLevel() & 2) {
+            _diaglog.readop(m.singleData().view2ptr(), m.header().getLen());
+        }
+    }
+
+    inline void opwrite(Message& m) {
+        if (_diaglog.getLevel() & 1) {
+            _diaglog.writeop(m.singleData().view2ptr(), m.header().getLen());
+        }
+    }
 
     void receivedKillCursors(OperationContext* txn, Message& m);
     void receivedUpdate(OperationContext* txn, Message& m, CurOp& op);
@@ -229,7 +238,7 @@ namespace mongo {
 
     static bool receivedQuery(OperationContext* txn, Client& c, DbResponse& dbresponse, Message& m ) {
         bool ok = true;
-        MSGID responseTo = m.header()->id;
+        MSGID responseTo = m.header().getId();
 
         DbMessage d(m);
         QueryMessage q(d);
@@ -286,26 +295,26 @@ namespace mongo {
             }
 
             BufBuilder b;
-            b.skip(sizeof(QueryResult));
+            b.skip(sizeof(QueryResult::Value));
             b.appendBuf((void*) errObj.objdata(), errObj.objsize());
 
             // todo: call replyToQuery() from here instead of this!!! see dbmessage.h
-            QueryResult * msgdata = (QueryResult *) b.buf();
+            QueryResult::View msgdata = b.buf();
             b.decouple();
-            QueryResult *qr = msgdata;
-            qr->_resultFlags() = ResultFlag_ErrSet;
-            if( scex ) qr->_resultFlags() |= ResultFlag_ShardConfigStale;
-            qr->len = b.len();
-            qr->setOperation(opReply);
-            qr->cursorId = 0;
-            qr->startingFrom = 0;
-            qr->nReturned = 1;
+            QueryResult::View qr = msgdata;
+            qr.setResultFlags(ResultFlag_ErrSet);
+            if( scex ) qr.setResultFlags(qr.getResultFlags() | ResultFlag_ShardConfigStale);
+            qr.msgdata().setLen(b.len());
+            qr.msgdata().setOperation(opReply);
+            qr.setCursorId(0);
+            qr.setStartingFrom(0);
+            qr.setNReturned(1);
             resp.reset( new Message() );
-            resp->setData( msgdata, true );
+            resp->setData( msgdata.view2ptr(), true );
 
         }
 
-        op.debug().responseLength = resp->header()->dataLen();
+        op.debug().responseLength = resp->header().dataLen();
 
         dbresponse.response = resp.release();
         dbresponse.responseTo = responseTo;
@@ -445,7 +454,7 @@ namespace mongo {
                 resp->setData( opReply , "i am fine - dbMsg deprecated");
 
             dbresponse.response = resp;
-            dbresponse.responseTo = m.header()->id;
+            dbresponse.responseTo = m.header().getId();
         }
         else {
             try {
@@ -537,7 +546,7 @@ namespace mongo {
             verify( n < 30000 );
         }
 
-        const long long* cursorArray = dbmessage.getArray(n);
+        const char* cursorArray = dbmessage.getArray(n);
 
         int found = CollectionCursorCache::eraseCursorGlobalIfAuthorized(txn, n, cursorArray);
 
@@ -556,11 +565,11 @@ namespace mongo {
         BSONObj query = d.nextJsObj();
 
         verify( d.moreJSObjs() );
-        verify( query.objsize() < m.header()->dataLen() );
+        verify( query.objsize() < m.header().dataLen() );
         BSONObj toupdate = d.nextJsObj();
         uassert( 10055 , "update object too large", toupdate.objsize() <= BSONObjMaxUserSize);
-        verify( toupdate.objsize() < m.header()->dataLen() );
-        verify( query.objsize() + toupdate.objsize() < m.header()->dataLen() );
+        verify( toupdate.objsize() < m.header().dataLen() );
+        verify( query.objsize() + toupdate.objsize() < m.header().dataLen() );
         bool upsert = flags & UpdateOption_Upsert;
         bool multi = flags & UpdateOption_Multi;
         bool broadcast = flags & UpdateOption_Broadcast;
@@ -640,7 +649,7 @@ namespace mongo {
         op.debug().ndeleted = n;
     }
 
-    QueryResult* emptyMoreResult(long long);
+    QueryResult::View emptyMoreResult(long long);
 
     bool receivedGetMore(OperationContext* txn, DbResponse& dbresponse, Message& m, CurOp& curop ) {
         bool ok = true;
@@ -659,7 +668,7 @@ namespace mongo {
         scoped_ptr<Timer> timer;
         int pass = 0;
         bool exhaust = false;
-        QueryResult* msgdata = 0;
+        QueryResult::View msgdata = 0;
         OpTime last;
         while( 1 ) {
             bool isCursorAuthorized = false;
@@ -709,7 +718,7 @@ namespace mongo {
                 break;
             }
             
-            if (msgdata == 0) {
+            if (msgdata.view2ptr() == 0) {
                 // this should only happen with QueryOption_AwaitData
                 exhaust = false;
                 massert(13073, "shutting down", !inShutdown() );
@@ -746,18 +755,18 @@ namespace mongo {
             curop.debug().exceptionInfo = ex->getInfo();
 
             replyToQuery(ResultFlag_ErrSet, m, dbresponse, errObj);
-            curop.debug().responseLength = dbresponse.response->header()->dataLen();
+            curop.debug().responseLength = dbresponse.response->header().dataLen();
             curop.debug().nreturned = 1;
             return ok;
         }
 
         Message *resp = new Message();
-        resp->setData(msgdata, true);
-        curop.debug().responseLength = resp->header()->dataLen();
-        curop.debug().nreturned = msgdata->nReturned;
+        resp->setData(msgdata.view2ptr(), true);
+        curop.debug().responseLength = resp->header().dataLen();
+        curop.debug().nreturned = msgdata.getNReturned();
 
         dbresponse.response = resp;
-        dbresponse.responseTo = m.header()->id;
+        dbresponse.responseTo = m.header().getId();
         
         if( exhaust ) {
             curop.debug().exhaust = true;
diff --git a/src/mongo/db/query/new_find.cpp b/src/mongo/db/query/new_find.cpp
index c480bca6f09..8c5ae0a3fb7 100644
--- a/src/mongo/db/query/new_find.cpp
+++ b/src/mongo/db/query/new_find.cpp
@@ -148,7 +148,7 @@ namespace mongo {
      *        when this method returns an empty result, incrementing pass on each call.  
      *        Thus, pass == 0 indicates this is the first "attempt" before any 'awaiting'.
      */
-    QueryResult* newGetMore(OperationContext* txn,
+    QueryResult::View newGetMore(OperationContext* txn,
                             const char* ns,
                             int ntoreturn,
                             long long cursorid,
@@ -193,9 +193,11 @@ namespace mongo {
         int numResults = 0;
         int startingResult = 0;
 
-        const int InitialBufSize = 512 + sizeof(QueryResult) + MaxBytesToReturnToClientAtOnce;
+        const int InitialBufSize =
+            512 + sizeof(QueryResult::Value) + MaxBytesToReturnToClientAtOnce;
+
         BufBuilder bb(InitialBufSize);
-        bb.skip(sizeof(QueryResult));
+        bb.skip(sizeof(QueryResult::Value));
 
         if (NULL == cc) {
             cursorid = 0;
@@ -345,13 +347,13 @@ namespace mongo {
             }
         }
 
-        QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
-        qr->len = bb.len();
-        qr->setOperation(opReply);
-        qr->_resultFlags() = resultFlags;
-        qr->cursorId = cursorid;
-        qr->startingFrom = startingResult;
-        qr->nReturned = numResults;
+        QueryResult::View qr = bb.buf();
+        qr.msgdata().setLen(bb.len());
+        qr.msgdata().setOperation(opReply);
+        qr.setResultFlags(resultFlags);
+        qr.setCursorId(cursorid);
+        qr.setStartingFrom(startingResult);
+        qr.setNReturned(numResults);
         bb.decouple();
         QLOG() << "getMore returned " << numResults << " results\n";
         return qr;
@@ -461,7 +463,7 @@ namespace mongo {
             curop.markCommand();
 
             BufBuilder bb;
-            bb.skip(sizeof(QueryResult));
+            bb.skip(sizeof(QueryResult::Value));
 
             BSONObjBuilder cmdResBuf;
             if (!runCommands(txn, ns, q.query, curop, bb, cmdResBuf, false, q.queryOptions)) {
@@ -472,16 +474,16 @@ namespace mongo {
             // TODO: Does this get overwritten/do we really need to set this twice?
             curop.debug().query = q.query;
 
-            QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
+            QueryResult::View qr = bb.buf();
             bb.decouple();
-            qr->setResultFlagsToOk();
-            qr->len = bb.len();
+            qr.setResultFlagsToOk();
+            qr.msgdata().setLen(bb.len());
             curop.debug().responseLength = bb.len();
-            qr->setOperation(opReply);
-            qr->cursorId = 0;
-            qr->startingFrom = 0;
-            qr->nReturned = 1;
-            result.setData(qr, true);
+            qr.msgdata().setOperation(opReply);
+            qr.setCursorId(0);
+            qr.setStartingFrom(0);
+            qr.setNReturned(1);
+            result.setData(qr.view2ptr(), true);
             return "";
         }
 
@@ -524,7 +526,7 @@ namespace mongo {
             }
 
             BufBuilder bb;
-            bb.skip(sizeof(QueryResult));
+            bb.skip(sizeof(QueryResult::Value));
 
             PlanExecutor* rawExec;
             // Takes ownership of 'cq'.
@@ -550,16 +552,16 @@ namespace mongo {
             curop.debug().query = q.query;
 
             // Set query result fields.
-            QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
+            QueryResult::View qr = bb.buf();
             bb.decouple();
-            qr->setResultFlagsToOk();
-            qr->len = bb.len();
+            qr.setResultFlagsToOk();
+            qr.msgdata().setLen(bb.len());
             curop.debug().responseLength = bb.len();
-            qr->setOperation(opReply);
-            qr->cursorId = 0;
-            qr->startingFrom = 0;
-            qr->nReturned = 1;
-            result.setData(qr, true);
+            qr.msgdata().setOperation(opReply);
+            qr.setCursorId(0);
+            qr.setStartingFrom(0);
+            qr.setNReturned(1);
+            result.setData(qr.view2ptr(), true);
             return "";
         }
 
@@ -636,7 +638,7 @@ namespace mongo {
         // this buffer should contain either requested documents per query or
         // explain information, but not both
         BufBuilder bb(32768);
-        bb.skip(sizeof(QueryResult));
+        bb.skip(sizeof(QueryResult::Value));
 
         // How many results have we obtained from the executor?
         int numResults = 0;
@@ -839,13 +841,13 @@ namespace mongo {
         bb.decouple();
 
         // Fill out the output buffer's header.
-        QueryResult* qr = static_cast<QueryResult*>(result.header());
-        qr->cursorId = ccId;
+        QueryResult::View qr = result.header().view2ptr();
+        qr.setCursorId(ccId);
         curop.debug().cursorid = (0 == ccId ? -1 : ccId);
-        qr->setResultFlagsToOk();
-        qr->setOperation(opReply);
-        qr->startingFrom = 0;
-        qr->nReturned = numResults;
+        qr.setResultFlagsToOk();
+        qr.msgdata().setOperation(opReply);
+        qr.setStartingFrom(0);
+        qr.setNReturned(numResults);
 
         // Set debug information for consumption by the profiler.
         curop.debug().ntoskip = pq.getSkip();
diff --git a/src/mongo/db/query/new_find.h b/src/mongo/db/query/new_find.h
index c136cee8981..99232c1088b 100644
--- a/src/mongo/db/query/new_find.h
+++ b/src/mongo/db/query/new_find.h
@@ -43,7 +43,7 @@ namespace mongo {
     /**
      * Called from the getMore entry point in ops/query.cpp.
      */
-    QueryResult* newGetMore(OperationContext* txn,
+    QueryResult::View newGetMore(OperationContext* txn,
                             const char* ns,
                             int ntoreturn,
                             long long cursorid,
diff --git a/src/mongo/dbtests/config_server_fixture.h b/src/mongo/dbtests/config_server_fixture.h
index b97eee7cd1d..9f61d8ba30c 100644
--- a/src/mongo/dbtests/config_server_fixture.h
+++ b/src/mongo/dbtests/config_server_fixture.h
@@ -52,21 +52,21 @@ namespace mongo {
             // This is tailored to act as a dummy response for write commands.
 
             BufBuilder bb;
-            bb.skip(sizeof(QueryResult));
+            bb.skip(sizeof(QueryResult::Value));
 
             BSONObj cmdResult(BSON("ok" << 1));
 
             bb.appendBuf(cmdResult.objdata(), cmdResult.objsize());
 
-            QueryResult* qr = reinterpret_cast<QueryResult*>(bb.buf());
+            QueryResult::View qr = bb.buf();
             bb.decouple();
-            qr->setResultFlagsToOk();
-            qr->len = bb.len();
-            qr->setOperation(opReply);
-            qr->cursorId = 0;
-            qr->startingFrom = 0;
-            qr->nReturned = 1;
-            m.setData(qr, true);
+            qr.setResultFlagsToOk();
+            qr.msgdata().setLen(bb.len());
+            qr.msgdata().setOperation(opReply);
+            qr.setCursorId(0);
+            qr.setStartingFrom(0);
+            qr.setNReturned(1);
+            m.setData(qr.view2ptr(), true);
 
             return true;
         }
diff --git a/src/mongo/s/cursors.cpp b/src/mongo/s/cursors.cpp
index 6f2b588e3fd..39d14ed9c8d 100644
--- a/src/mongo/s/cursors.cpp
+++ b/src/mongo/s/cursors.cpp
@@ -34,6 +34,7 @@
 #include <string>
 #include <vector>
 
+#include "mongo/base/data_cursor.h"
 #include "mongo/db/audit.h"
 #include "mongo/db/auth/action_set.h"
 #include "mongo/db/auth/action_type.h"
@@ -346,11 +347,12 @@ namespace mongo {
                     m.dataSize() == 8 + ( 8 * n ) );
 
 
-        const long long* cursors = dbmessage.getArray(n);
+        ConstDataCursor cursors(dbmessage.getArray(n));
+
         ClientBasic* client = ClientBasic::getCurrent();
         AuthorizationSession* authSession = client->getAuthorizationSession();
         for ( int i=0; i<n; i++ ) {
-            long long id = cursors[i];
+            long long id = cursors.readLEAndAdvance<int64_t>();
             LOG(_myLogLevel) << "CursorCache::gotKillCursors id: " << id << endl;
 
             if ( ! id ) {
diff --git a/src/mongo/s/d_logic.cpp b/src/mongo/s/d_logic.cpp
index e183e97d523..0c036f65c3d 100644
--- a/src/mongo/s/d_logic.cpp
+++ b/src/mongo/s/d_logic.cpp
@@ -85,7 +85,7 @@ namespace mongo {
         if( getsAResponse ){
             verify( dbresponse );
             BufBuilder b( 32768 );
-            b.skip( sizeof( QueryResult ) );
+            b.skip( sizeof( QueryResult::Value ) );
             {
                 BSONObjBuilder bob;
 
@@ -99,20 +99,20 @@ namespace mongo {
                 b.appendBuf( obj.objdata() , obj.objsize() );
             }
 
-            QueryResult *qr = (QueryResult*)b.buf();
-            qr->_resultFlags() = ResultFlag_ErrSet | ResultFlag_ShardConfigStale;
-            qr->len = b.len();
-            qr->setOperation( opReply );
-            qr->cursorId = 0;
-            qr->startingFrom = 0;
-            qr->nReturned = 1;
+            QueryResult::View qr = b.buf();
+            qr.setResultFlags(ResultFlag_ErrSet | ResultFlag_ShardConfigStale);
+            qr.msgdata().setLen(b.len());
+            qr.msgdata().setOperation( opReply );
+            qr.setCursorId(0);
+            qr.setStartingFrom(0);
+            qr.setNReturned(1);
             b.decouple();
 
             Message * resp = new Message();
-            resp->setData( qr , true );
+            resp->setData( qr.view2ptr() , true );
 
             dbresponse->response = resp;
-            dbresponse->responseTo = m.header()->id;
+            dbresponse->responseTo = m.header().getId();
             return true;
         }
 
@@ -139,8 +139,10 @@ namespace mongo {
         wanted.addToBSON( b );
         received.addToBSON( b, "yourVersion" );
 
-        b.appendBinData( "msg" , m.header()->len , bdtCustom , (char*)(m.singleData()) );
-        LOG(2) << "writing back msg with len: " << m.header()->len << " op: " << m.operation() << endl;
+        b.appendBinData( "msg" , m.header().getLen() , bdtCustom , m.singleData().view2ptr() );
+
+        LOG(2) << "writing back msg with len: " << m.header().getLen()
+               << " op: " << m.operation() << endl;
         
         // we pass the builder to queueWriteBack so that it can select the writebackId
         // this is important so that the id is guaranteed to be ascending 
diff --git a/src/mongo/s/dbclient_multi_command.cpp b/src/mongo/s/dbclient_multi_command.cpp
index a6251f311cf..09bdacfe63a 100644
--- a/src/mongo/s/dbclient_multi_command.cpp
+++ b/src/mongo/s/dbclient_multi_command.cpp
@@ -146,8 +146,8 @@ namespace mongo {
         }
 
         // A query result is returned from commands
-        QueryResult* recvdQuery = reinterpret_cast<QueryResult*>( toRecv->singleData() );
-        *result = BSONObj( recvdQuery->data() );
+        QueryResult::View recvdQuery = toRecv->singleData().view2ptr();
+        *result = BSONObj( recvdQuery.data() );
     }
 
     void DBClientMultiCommand::sendAll() {
diff --git a/src/mongo/s/request.cpp b/src/mongo/s/request.cpp
index f3d09e191f9..06f355f82f1 100644
--- a/src/mongo/s/request.cpp
+++ b/src/mongo/s/request.cpp
@@ -53,7 +53,7 @@ namespace mongo {
     Request::Request( Message& m, AbstractMessagingPort* p ) :
         _m(m) , _d( m ) , _p(p) , _didInit(false) {
 
-        _id = _m.header()->id;
+        _id = _m.header().getId();
 
         _txn.reset(new OperationContextNoop());
 
@@ -76,7 +76,7 @@ namespace mongo {
 
     // Deprecated, will move to the strategy itself
     void Request::reset() {
-        _m.header()->id = _id;
+        _m.header().setId(_id);
         _clientInfo->clearRequestInfo();
 
         if ( !_d.messageShouldHaveNs()) {
@@ -93,7 +93,7 @@ namespace mongo {
         int op = _m.operation();
         verify( op > dbMsg );
 
-        int msgId = (int)(_m.header()->id);
+        int msgId = (int)(_m.header().getId());
 
         Timer t;
         LOG(3) << "Request::process begin ns: " << getns()
@@ -146,7 +146,7 @@ namespace mongo {
 
     void Request::reply( Message & response , const string& fromServer ) {
         verify( _didInit );
-        long long cursor =response.header()->getCursor();
+        long long cursor = response.header().getCursor();
         if ( cursor ) {
             if ( fromServer.size() ) {
                 cursorCache.storeRef(fromServer, cursor, getns());
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index 1cd1eb97914..324d94224e1 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -150,7 +150,7 @@ namespace mongo {
                     << " for " << r.getns() << causedBy( ex ) << endl;
 
                 if ( r.expectResponse() ) {
-                    m.header()->id = r.id();
+                    m.header().setId(r.id());
                     replyToQuery( ResultFlag_ErrSet, p , m , buildErrReply( ex ) );
                 }
 
@@ -164,7 +164,7 @@ namespace mongo {
                       << " for " << r.getns() << causedBy( ex ) << endl;
 
                 if ( r.expectResponse() ) {
-                    m.header()->id = r.id();
+                    m.header().setId(r.id());
                     replyToQuery( ResultFlag_ErrSet, p , m , buildErrReply( ex ) );
                 }
 
diff --git a/src/mongo/s/strategy.cpp b/src/mongo/s/strategy.cpp
index 63fe466cdc2..7fa0147e1c4 100644
--- a/src/mongo/s/strategy.cpp
+++ b/src/mongo/s/strategy.cpp
@@ -105,8 +105,8 @@ namespace mongo {
         uassert( 10200 , "mongos: error calling db", ok );
 
         {
-            QueryResult *qr = (QueryResult *) response.singleData();
-            if ( qr->resultFlags() & ResultFlag_ShardConfigStale ) {
+            QueryResult::View qr = response.singleData().view2ptr();
+            if ( qr.getResultFlags() & ResultFlag_ShardConfigStale ) {
                 dbcon.done();
                 // Version is zero b/c this is deprecated codepath
                 throw RecvStaleConfigException( r.getns(),
@@ -498,7 +498,7 @@ namespace mongo {
             bool ok = conn->callRead( r.m() , response);
             uassert( 10204 , "dbgrid: getmore: error calling db", ok);
 
-            bool hasMore = (response.singleData()->getCursor() != 0);
+            bool hasMore = (response.singleData().getCursor() != 0);
 
             if ( !hasMore ) {
                 cursorCache.removeRef( id );
diff --git a/src/mongo/tools/bridge.cpp b/src/mongo/tools/bridge.cpp
index 663260aea5f..7181258505c 100644
--- a/src/mongo/tools/bridge.cpp
+++ b/src/mongo/tools/bridge.cpp
@@ -80,7 +80,7 @@ public:
                 }
                 sleepmillis(mongoBridgeGlobalParams.delay);
 
-                int oldId = m.header()->id;
+                int oldId = m.header().getId();
                 if ( m.operation() == dbQuery || m.operation() == dbMsg || m.operation() == dbGetMore ) {
                     bool exhaust = false;
                     if ( m.operation() == dbQuery ) {
@@ -96,9 +96,9 @@ public:
 
                     mp_.reply( m, response, oldId );
                     while ( exhaust ) {
-                        MsgData *header = response.header();
-                        QueryResult *qr = (QueryResult *) header;
-                        if ( qr->cursorId ) {
+                        MsgData::View header = response.header();
+                        QueryResult::View qr = header.view2ptr();
+                        if ( qr.getCursorId() ) {
                             response.reset();
                             dest.port().recv( response );
                             mp_.reply( m, response ); // m argument is ignored anyway
diff --git a/src/mongo/tools/sniffer.cpp b/src/mongo/tools/sniffer.cpp
index 9e39a3b1d15..c4da46703fb 100644
--- a/src/mongo/tools/sniffer.cpp
+++ b/src/mongo/tools/sniffer.cpp
@@ -71,12 +71,10 @@
 
 using namespace std;
 using mongo::Message;
-using mongo::MsgData;
 using mongo::DbMessage;
 using mongo::BSONObj;
 using mongo::BufBuilder;
 using mongo::DBClientConnection;
-using mongo::QueryResult;
 using mongo::MemoryMappedFile;
 
 #define SNAP_LEN 65535
@@ -222,17 +220,17 @@ void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *pa
     Message m;
 
     if ( bytesRemainingInMessage[ c ] == 0 ) {
-        m.setData( (MsgData*)payload , false );
-        if ( !m.header()->valid() ) {
+        m.setData( const_cast<char *>(reinterpret_cast<const char *>(payload)) , false );
+        if ( !m.header().valid() ) {
             cerr << "Invalid message start, skipping packet." << endl;
             return;
         }
-        if ( size_payload > m.header()->len ) {
+        if ( size_payload > m.header().getLen() ) {
             cerr << "Multiple messages in packet, skipping packet." << endl;
             return;
         }
-        if ( size_payload < m.header()->len ) {
-            bytesRemainingInMessage[ c ] = m.header()->len - size_payload;
+        if ( size_payload < m.header().getLen() ) {
+            bytesRemainingInMessage[ c ] = m.header().getLen() - size_payload;
             messageBuilder[ c ].reset( new BufBuilder() );
             messageBuilder[ c ]->appendBuf( (void*)payload, size_payload );
             return;
@@ -249,7 +247,7 @@ void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *pa
         }
         if ( bytesRemainingInMessage[ c ] > 0 )
             return;
-        m.setData( (MsgData*)messageBuilder[ c ]->buf(), true );
+        m.setData( messageBuilder[ c ]->buf(), true );
         messageBuilder[ c ]->decouple();
         messageBuilder[ c ].reset();
     }
@@ -260,8 +258,8 @@ void got_packet(u_char *args, const struct pcap_pkthdr *header, const u_char *pa
           << ( serverPorts.count( ntohs( tcp->th_dport ) ) ? "  -->> " : "  <<--  " )
           << inet_ntoa(ip->ip_dst) << ":" << ntohs( tcp->th_dport )
           << " " << d.getns()
-          << "  " << m.header()->len << " bytes "
-          << " id:" << hex << m.header()->id << dec << "\t" << m.header()->id;
+          << "  " << m.header().getLen() << " bytes "
+          << " id:" << hex << m.header().getId() << dec << "\t" << m.header().getId();
 
     processMessage( c , m );
 }
@@ -283,16 +281,21 @@ void processMessage( Connection& c , Message& m ) {
     AuditingDbMessage d(m);
 
     if ( m.operation() == mongo::opReply )
-        out() << " - " << (unsigned)m.header()->responseTo;
+        out() << " - " << (unsigned)m.header().getResponseTo();
     out() << '\n';
 
     try {
         switch( m.operation() ) {
         case mongo::opReply: {
-            mongo::QueryResult* r = (mongo::QueryResult*)m.singleData();
-            out() << "\treply" << " n:" << r->nReturned << " cursorId: " << r->cursorId << endl;
-            if ( r->nReturned ) {
-                mongo::BSONObj o( r->data() );
+            mongo::QueryResult::View r = m.singleData().view2ptr();
+
+            out() << "\treply"
+                  << " n:" << r.getNReturned()
+                  << " cursorId: " << r.getCursorId()
+                  << endl;
+
+            if ( r.getNReturned() ) {
+                mongo::BSONObj o( r.data() );
                 out() << "\t" << o << endl;
             }
             break;
@@ -369,10 +372,10 @@ void processMessage( Connection& c , Message& m ) {
                 }
                 Message response;
                 conn->port().call( m, response );
-                QueryResult *qr = (QueryResult *) response.singleData();
-                if ( !( qr->resultFlags() & mongo::ResultFlag_CursorNotFound ) ) {
-                    if ( qr->cursorId != 0 ) {
-                        lastCursor[ c ] = qr->cursorId;
+                mongo::QueryResult::View qr = response.singleData().view2ptr();
+                if ( !( qr.getResultFlags() & mongo::ResultFlag_CursorNotFound ) ) {
+                    if ( qr.getCursorId() != 0 ) {
+                        lastCursor[ c ] = qr.getCursorId();
                         return;
                     }
                 }
@@ -385,16 +388,16 @@ void processMessage( Connection& c , Message& m ) {
         else {
             Connection r = c.reverse();
             long long myCursor = lastCursor[ r ];
-            QueryResult *qr = (QueryResult *) m.singleData();
-            long long yourCursor = qr->cursorId;
-            if ( ( qr->resultFlags() & mongo::ResultFlag_CursorNotFound ) )
+            mongo::QueryResult::View qr = m.singleData().view2ptr();
+            long long yourCursor = qr.getCursorId();
+            if ( ( qr.getResultFlags() & mongo::ResultFlag_CursorNotFound ) )
                 yourCursor = 0;
             if ( myCursor && !yourCursor )
                 cerr << "Expected valid cursor in sniffed response, found none" << endl;
             if ( !myCursor && yourCursor )
                 cerr << "Sniffed valid cursor when none expected" << endl;
             if ( myCursor && yourCursor ) {
-                mapCursor[ r ][ qr->cursorId ] = lastCursor[ r ];
+                mapCursor[ r ][ qr.getCursorId() ] = lastCursor[ r ];
                 lastCursor[ r ] = 0;
             }
         }
@@ -417,7 +420,7 @@ void processDiagLog( const char * file ) {
     long read = 0;
     while ( read < length ) {
         Message m(pos,false);
-        int len = m.header()->len;
+        int len = m.header().getLen();
         DbMessage d(m);
         cout << len << " " << d.getns() << endl;
 
diff --git a/src/mongo/util/goodies.h b/src/mongo/util/goodies.h
index 74e48bd65b7..4be632afed7 100644
--- a/src/mongo/util/goodies.h
+++ b/src/mongo/util/goodies.h
@@ -33,7 +33,6 @@
 #include <iostream>
 #include <sstream>
 
-#include <boost/detail/endian.hpp>
 #include <boost/intrusive_ptr.hpp>
 #include <boost/scoped_array.hpp>
 #include <boost/scoped_ptr.hpp>
@@ -108,26 +107,6 @@ namespace mongo {
         return strcmp(p + a - b, suffix) == 0;
     }
 
-    inline unsigned long swapEndian(unsigned long x) {
-        return
-            ((x & 0xff) << 24) |
-            ((x & 0xff00) << 8) |
-            ((x & 0xff0000) >> 8) |
-            ((x & 0xff000000) >> 24);
-    }
-
-#if defined(BOOST_LITTLE_ENDIAN)
-    inline unsigned long fixEndian(unsigned long x) {
-        return x;
-    }
-#elif defined(BOOST_BIG_ENDIAN)
-    inline unsigned long fixEndian(unsigned long x) {
-        return swapEndian(x);
-    }
-#else
-#error no boost endian header defined
-#endif
-
 #if !defined(_WIN32)
     typedef int HANDLE;
     inline void strcpy_s(char *dst, unsigned len, const char *src) {
diff --git a/src/mongo/util/net/message.cpp b/src/mongo/util/net/message.cpp
index e3b7eb1f139..ce038190601 100644
--- a/src/mongo/util/net/message.cpp
+++ b/src/mongo/util/net/message.cpp
@@ -46,7 +46,7 @@ namespace mongo {
             return;
         }
         if ( _buf != 0 ) {
-            p.send( (char*)_buf, _buf->len, context );
+            p.send( _buf, MsgData::ConstView(_buf).getLen(), context );
         }
         else {
             p.send( _data, context );
diff --git a/src/mongo/util/net/message.h b/src/mongo/util/net/message.h
index 80205e1d1f5..3c7bffa7654 100644
--- a/src/mongo/util/net/message.h
+++ b/src/mongo/util/net/message.h
@@ -33,6 +33,8 @@
 
 #include "mongo/platform/atomic_word.h"
 #include "mongo/platform/cstdint.h"
+#include "mongo/base/data_view.h"
+#include "mongo/base/encoded_value_storage.h"
 #include "mongo/util/goodies.h"
 #include "mongo/util/mongoutils/str.h"
 #include "mongo/util/net/hostandport.h"
@@ -106,77 +108,225 @@ namespace mongo {
 
     }
 
+    namespace MSGHEADER {
 #pragma pack(1)
-    /* see http://dochub.mongodb.org/core/mongowireprotocol
-    */
-    struct MSGHEADER {
-        int messageLength; // total message size, including this
-        int requestID;     // identifier for this message
-        int responseTo;    // requestID from the original request
-        //   (used in responses from db)
-        int opCode;
-    };
+        /* see http://dochub.mongodb.org/core/mongowireprotocol
+        */
+        struct Layout {
+            int32_t messageLength; // total message size, including this
+            int32_t requestID;     // identifier for this message
+            int32_t responseTo;    // requestID from the original request
+            //   (used in responses from db)
+            int32_t opCode;
+        };
 #pragma pack()
 
-#pragma pack(1)
-    /* todo merge this with MSGHEADER (or inherit from it). */
-    class MsgData {
-        friend class Message;
-        friend class DbMessage;
-        friend class MessagingPort;
-    public:
-        int len; /* len of the msg, including this field */
-        MSGID id; /* request/reply id's match... */
-        MSGID responseTo; /* id of the message we are responding to */
-        short _operation;
-        char _flags;
-        char _version;
-
-        int operation() const {
-            return _operation;
-        }
-        void setOperation(int o) {
-            _flags = 0;
-            _version = 0;
-            _operation = o;
-        }
+        class ConstView {
+        public:
+            typedef ConstDataView view_type;
 
-        int& dataAsInt() {
-            return *((int *) _data);
-        }
+            ConstView(const char* data) : _data(data) { }
 
-        bool valid() {
-            if ( len <= 0 || len > ( 4 * BSONObjMaxInternalSize ) )
-                return false;
-            if ( _operation < 0 || _operation > 30000 )
-                return false;
-            return true;
-        }
+            const char* view2ptr() const {
+                return data().view();
+            }
 
-        long long getCursor() {
-            verify( responseTo > 0 );
-            verify( _operation == opReply );
-            long long * l = (long long *)(_data + 4);
-            return l[0];
-        }
+            int32_t getMessageLength() const {
+                return data().readLE<int32_t>(offsetof(Layout, messageLength));
+            }
 
-        int dataLen(); // len without header
-    private:
-        char _data[4]; //must be last member
-    };
-    const int MsgDataHeaderSize = sizeof(MsgData) - 4;
-    inline int MsgData::dataLen() {
-        return len - MsgDataHeaderSize;
-    }
+            int32_t getRequestID() const {
+                return data().readLE<int32_t>(offsetof(Layout, requestID));
+            }
+
+            int32_t getResponseTo() const {
+                return data().readLE<int32_t>(offsetof(Layout, responseTo));
+            }
+
+            int32_t getOpCode() const {
+                return data().readLE<int32_t>(offsetof(Layout, opCode));
+            }
+
+        protected:
+            const view_type& data() const {
+                return _data;
+            }
+
+        private:
+            view_type _data;
+        };
+
+        class View : public ConstView {
+        public:
+            typedef DataView view_type;
+
+            View(char* data) : ConstView(data) {}
+
+            using ConstView::view2ptr;
+            char* view2ptr() {
+                return data().view();
+            }
+
+            void setMessageLength(int32_t value) {
+                return data().writeLE(value, offsetof(Layout, messageLength));
+            }
+
+            void setRequestID(int32_t value) {
+                return data().writeLE(value, offsetof(Layout, requestID));
+            }
+
+            void setResponseTo(int32_t value) {
+                return data().writeLE(value, offsetof(Layout, responseTo));
+            }
+
+            void setOpCode(int32_t value) {
+                return data().writeLE(value, offsetof(Layout, opCode));
+            }
+
+        private:
+            view_type data() const {
+                return const_cast<char *>(ConstView::view2ptr());
+            }
+        };
+
+        class Value : public EncodedValueStorage<Layout, ConstView, View> {
+        public:
+            Value() {
+                BOOST_STATIC_ASSERT(sizeof(Value) == sizeof(Layout));
+            }
+
+            Value(ZeroInitTag_t zit) : EncodedValueStorage<Layout, ConstView, View>(zit) {}
+        };
+
+    } // namespace MSGHEADER
+
+    namespace MsgData {
+#pragma pack(1)
+        struct Layout {
+            MSGHEADER::Layout header;
+            char data[4];
+        };
 #pragma pack()
 
+        class ConstView {
+        public:
+            ConstView(const char* storage) : _storage(storage) { }
+
+            const char* view2ptr() const {
+                return storage().view();
+            }
+
+            int32_t getLen() const {
+                return header().getMessageLength();
+            }
+
+            MSGID getId() const {
+                return header().getRequestID();
+            }
+
+            MSGID getResponseTo() const {
+                return header().getResponseTo();
+            }
+
+            int32_t getOperation() const {
+                return header().getOpCode();
+            }
+
+            const char* data() const {
+                return storage().view(offsetof(Layout, data));
+            }
+
+            bool valid() const {
+                if ( getLen() <= 0 || getLen() > ( 4 * BSONObjMaxInternalSize ) )
+                    return false;
+                if ( getOperation() < 0 || getOperation() > 30000 )
+                    return false;
+                return true;
+            }
+
+            int64_t getCursor() const {
+                verify( getResponseTo() > 0 );
+                verify( getOperation() == opReply );
+                return ConstDataView(data() + sizeof(int32_t)).readLE<int64_t>();
+            }
+
+            int dataLen() const; // len without header
+
+        protected:
+            const ConstDataView& storage() const {
+                return _storage;
+            }
+
+            MSGHEADER::ConstView header() const {
+                return storage().view(offsetof(Layout, header));
+            }
+
+        private:
+            ConstDataView _storage;
+        };
+
+        class View : public ConstView {
+        public:
+            View(char* storage) : ConstView(storage) {}
+
+            using ConstView::view2ptr;
+            char* view2ptr() {
+                return storage().view();
+            }
+
+            void setLen(int value) {
+                return header().setMessageLength(value);
+            }
+
+            void setId(MSGID value) {
+                return header().setRequestID(value);
+            }
+
+            void setResponseTo(MSGID value) {
+                return header().setResponseTo(value);
+            }
+
+            void setOperation(int value) {
+                return header().setOpCode(value);
+            }
+
+            using ConstView::data;
+            char* data() {
+                return storage().view(offsetof(Layout, data));
+            }
+
+        private:
+            DataView storage() const {
+                return const_cast<char *>(ConstView::view2ptr());
+            }
+
+            MSGHEADER::View header() const {
+                return storage().view(offsetof(Layout, header));
+            }
+        };
+
+        class Value : public EncodedValueStorage<Layout, ConstView, View> {
+        public:
+            Value() {
+                BOOST_STATIC_ASSERT(sizeof(Value) == sizeof(Layout));
+            }
+
+            Value(ZeroInitTag_t zit) : EncodedValueStorage<Layout, ConstView, View>(zit) {}
+        };
+
+        const int MsgDataHeaderSize = sizeof(Value) - 4;
+        inline int ConstView::dataLen() const {
+            return getLen() - MsgDataHeaderSize;
+        }
+    } // namespace MsgData
+
     class Message {
     public:
         // we assume here that a vector with initial size 0 does no allocation (0 is the default, but wanted to make it explicit).
         Message() : _buf( 0 ), _data( 0 ), _freeIt( false ) {}
         Message( void * data , bool freeIt ) :
             _buf( 0 ), _data( 0 ), _freeIt( false ) {
-            _setData( reinterpret_cast< MsgData* >( data ), freeIt );
+            _setData( reinterpret_cast< char* >( data ), freeIt );
         };
         Message(Message& r) : _buf( 0 ), _data( 0 ), _freeIt( false ) {
             *this = r;
@@ -187,13 +337,14 @@ namespace mongo {
 
         SockAddr _from;
 
-        MsgData *header() const {
+        MsgData::View header() const {
             verify( !empty() );
-            return _buf ? _buf : reinterpret_cast< MsgData* > ( _data[ 0 ].first );
+            return _buf ? _buf : _data[ 0 ].first;
         }
-        int operation() const { return header()->operation(); }
 
-        MsgData *singleData() const {
+        int operation() const { return header().getOperation(); }
+
+        MsgData::View singleData() const {
             massert( 13273, "single data buffer expected", _buf );
             return header();
         }
@@ -203,7 +354,7 @@ namespace mongo {
         int size() const {
             int res = 0;
             if ( _buf ) {
-                res =  _buf->len;
+                res =  MsgData::ConstView(_buf).getLen();
             }
             else {
                 for (MsgVec::const_iterator it = _data.begin(); it != _data.end(); ++it) {
@@ -213,7 +364,7 @@ namespace mongo {
             return res;
         }
 
-        int dataSize() const { return size() - sizeof(MSGHEADER); }
+        int dataSize() const { return size() - sizeof(MSGHEADER::Value); }
 
         // concat multiple buffers - noop if <2 buffers already, otherwise can be expensive copy
         // can get rid of this if we make response handling smarter
@@ -236,7 +387,7 @@ namespace mongo {
                 p += i->second;
             }
             reset();
-            _setData( (MsgData*)buf, true );
+            _setData( buf, true );
         }
 
         // vector swap() so this is fast
@@ -275,22 +426,22 @@ namespace mongo {
                 return;
             }
             if ( empty() ) {
-                MsgData *md = (MsgData*)d;
-                md->len = size; // can be updated later if more buffers added
-                _setData( md, true );
+                MsgData::View md = d;
+                md.setLen(size); // can be updated later if more buffers added
+                _setData( md.view2ptr(), true );
                 return;
             }
             verify( _freeIt );
             if ( _buf ) {
-                _data.push_back(std::make_pair((char*)_buf, _buf->len));
+                _data.push_back(std::make_pair(_buf, MsgData::ConstView(_buf).getLen()));
                 _buf = 0;
             }
             _data.push_back(std::make_pair(d, size));
-            header()->len += size;
+            header().setLen(header().getLen() + size);
         }
 
         // use to set first buffer if empty
-        void setData(MsgData *d, bool freeIt) {
+        void setData(char* d, bool freeIt) {
             verify( empty() );
             _setData( d, freeIt );
         }
@@ -299,12 +450,12 @@ namespace mongo {
         }
         void setData(int operation, const char *msgdata, size_t len) {
             verify( empty() );
-            size_t dataLen = len + sizeof(MsgData) - 4;
-            MsgData *d = (MsgData *) malloc(dataLen);
-            memcpy(d->_data, msgdata, len);
-            d->len = fixEndian(dataLen);
-            d->setOperation(operation);
-            _setData( d, true );
+            size_t dataLen = len + sizeof(MsgData::Value) - 4;
+            MsgData::View d = reinterpret_cast<char *>(malloc(dataLen));
+            memcpy(d.data(), msgdata, len);
+            d.setLen(dataLen);
+            d.setOperation(operation);
+            _setData( d.view2ptr(), true );
         }
 
         bool doIFreeIt() {
@@ -316,12 +467,12 @@ namespace mongo {
         std::string toString() const;
 
     private:
-        void _setData( MsgData *d, bool freeIt ) {
+        void _setData( char* d, bool freeIt ) {
             _freeIt = freeIt;
             _buf = d;
         }
         // if just one buffer, keep it in _buf, otherwise keep a sequence of buffers in _data
-        MsgData * _buf;
+        char* _buf;
         // byte buffer(s) - the first must contain at least a full MsgData unless using _buf for storage instead
         typedef std::vector< std::pair< char*, int > > MsgVec;
         MsgVec _data;
diff --git a/src/mongo/util/net/message_port.cpp b/src/mongo/util/net/message_port.cpp
index 2c4d723d79f..8dc67ab2896 100644
--- a/src/mongo/util/net/message_port.cpp
+++ b/src/mongo/util/net/message_port.cpp
@@ -82,13 +82,13 @@ namespace mongo {
         }
 
         void append( Message& m ) {
-            verify( m.header()->len <= 1300 );
+            verify( m.header().getLen() <= 1300 );
 
-            if ( len() + m.header()->len > 1300 )
+            if ( len() + m.header().getLen() > 1300 )
                 flush();
 
-            memcpy( _cur , m.singleData() , m.header()->len );
-            _cur += m.header()->len;
+            memcpy( _cur , m.singleData().view2ptr() , m.header().getLen() );
+            _cur += m.header().getLen();
         }
 
         void flush() {
@@ -173,10 +173,10 @@ namespace mongo {
         try {
 again:
             //mmm( log() << "*  recv() sock:" << this->sock << endl; )
-            MSGHEADER header;
-            int headerLen = sizeof(MSGHEADER);
+            MSGHEADER::Value header;
+            int headerLen = sizeof(MSGHEADER::Value);
             psock->recv( (char *)&header, headerLen );
-            int len = header.messageLength; 
+            int len = header.constView().getMessageLength();
 
             if ( len == 542393671 ) {
                 // an http GET
@@ -198,12 +198,14 @@ again:
             // If responseTo is not 0 or -1 for first packet assume SSL
             else if (psock->isAwaitingHandshake()) {
 #ifndef MONGO_SSL
-                if (header.responseTo != 0 && header.responseTo != -1) {
+                if (header.constView().getResponseTo() != 0
+                 && header.constView().getResponseTo() != -1) {
                     uasserted(17133,
                               "SSL handshake requested, SSL feature not available in this build");
                 }
 #else                    
-                if (header.responseTo != 0 && header.responseTo != -1) {
+                if (header.constView().getResponseTo() != 0
+                 && header.constView().getResponseTo() != -1) {
                     uassert(17132,
                             "SSL handshake received but server is started without SSL support",
                             sslGlobalParams.sslMode.load() != SSLGlobalParams::SSLMode_disabled);
@@ -216,27 +218,27 @@ again:
                         sslGlobalParams.sslMode.load() != SSLGlobalParams::SSLMode_requireSSL);
 #endif // MONGO_SSL
             }
-            if ( static_cast<size_t>(len) < sizeof(MSGHEADER) || 
+            if ( static_cast<size_t>(len) < sizeof(MSGHEADER::Value) ||
                  static_cast<size_t>(len) > MaxMessageSizeBytes ) {
                 LOG(0) << "recv(): message len " << len << " is invalid. "
-                       << "Min " << sizeof(MSGHEADER) << " Max: " << MaxMessageSizeBytes;
+                       << "Min " << sizeof(MSGHEADER::Value) << " Max: " << MaxMessageSizeBytes;
                 return false;
             }
 
             psock->setHandshakeReceived();
             int z = (len+1023)&0xfffffc00;
             verify(z>=len);
-            MsgData *md = (MsgData *) malloc(z);
-            ScopeGuard guard = MakeGuard(free, md);
-            verify(md);
+            MsgData::View md = reinterpret_cast<char *>(malloc(z));
+            ScopeGuard guard = MakeGuard(free, md.view2ptr());
+            verify(md.view2ptr());
 
-            memcpy(md, &header, headerLen);
+            memcpy(md.view2ptr(), &header, headerLen);
             int left = len - headerLen;
 
-            psock->recv( (char *)&md->_data, left );
+            psock->recv( md.data(), left );
 
             guard.Dismiss();
-            m.setData(md, true);
+            m.setData(md.view2ptr(), true);
             return true;
 
         }
@@ -251,7 +253,7 @@ again:
     }
 
     void MessagingPort::reply(Message& received, Message& response) {
-        say(/*received.from, */response, received.header()->id);
+        say(/*received.from, */response, received.header().getId());
     }
 
     void MessagingPort::reply(Message& received, Message& response, MSGID responseTo) {
@@ -272,13 +274,15 @@ again:
                 return false;
             }
             //log() << "got response: " << response.data->responseTo << endl;
-            if ( response.header()->responseTo == toSend.header()->id )
+            if ( response.header().getResponseTo() == toSend.header().getId() )
                 break;
-            error() << "MessagingPort::call() wrong id got:" << std::hex << (unsigned)response.header()->responseTo << " expect:" << (unsigned)toSend.header()->id << '\n'
+            error() << "MessagingPort::call() wrong id got:"
+                    << std::hex << (unsigned)response.header().getResponseTo()
+                    << " expect:" << (unsigned)toSend.header().getId() << '\n'
                     << std::dec
                     << "  toSend op: " << (unsigned)toSend.operation() << '\n'
-                    << "  response msgid:" << (unsigned)response.header()->id << '\n'
-                    << "  response len:  " << (unsigned)response.header()->len << '\n'
+                    << "  response msgid:" << (unsigned)response.header().getId() << '\n'
+                    << "  response len:  " << (unsigned)response.header().getLen() << '\n'
                     << "  response op:  " << response.operation() << '\n'
                     << "  remote: " << psock->remoteString();
             verify(false);
@@ -291,12 +295,12 @@ again:
     void MessagingPort::say(Message& toSend, int responseTo) {
         verify( !toSend.empty() );
         mmm( log() << "*  say()  thr:" << GetCurrentThreadId() << endl; )
-        toSend.header()->id = nextMessageId();
-        toSend.header()->responseTo = responseTo;
+        toSend.header().setId(nextMessageId());
+        toSend.header().setResponseTo(responseTo);
 
         if ( piggyBackData && piggyBackData->len() ) {
             mmm( log() << "*     have piggy back" << endl; )
-            if ( ( piggyBackData->len() + toSend.header()->len ) > 1300 ) {
+            if ( ( piggyBackData->len() + toSend.header().getLen() ) > 1300 ) {
                 // won't fit in a packet - so just send it off
                 piggyBackData->flush();
             }
@@ -312,15 +316,15 @@ again:
 
     void MessagingPort::piggyBack( Message& toSend , int responseTo ) {
 
-        if ( toSend.header()->len > 1300 ) {
+        if ( toSend.header().getLen() > 1300 ) {
             // not worth saving because its almost an entire packet
             say( toSend );
             return;
         }
 
         // we're going to be storing this, so need to set it up
-        toSend.header()->id = nextMessageId();
-        toSend.header()->responseTo = responseTo;
+        toSend.header().setId(nextMessageId());
+        toSend.header().setResponseTo(responseTo);
 
         if ( ! piggyBackData )
             piggyBackData = new PiggyBackData( this );
diff --git a/src/mongo/util/util.cpp b/src/mongo/util/util.cpp
index ae004ee41b4..f510aa6c31a 100644
--- a/src/mongo/util/util.cpp
+++ b/src/mongo/util/util.cpp
@@ -86,9 +86,6 @@ namespace mongo {
 
             verify( endsWith("abcde", "de") );
             verify( !endsWith("abcde", "dasdfasdfashkfde") );
-
-            verify( swapEndian(0x01020304) == 0x04030201 );
-
         }
     } utilTest;