SERVER-17629 Implemented Bounded Data View/Cursor

Implements DataRange and DataRangeCursor, bounded Status returning
variants of DataView and DataCursor.

Implements DataType::Handler<> to allow for specialization by type.
* Endian specializations
* BSONObj specialization

Fix for endian conversions for floats and doubles to avoid some
signaling bit patterns.

5 files changed, 17 insertions, 14 deletions

diff --git a/src/mongo/db/catalog/cursor_manager.cpp b/src/mongo/db/catalog/cursor_manager.cpp
index f68c6cbc1ab..0ea4f588839 100644
--- a/src/mongo/db/catalog/cursor_manager.cpp
+++ b/src/mongo/db/catalog/cursor_manager.cpp
@@ -298,7 +298,7 @@ namespace mongo {
         ConstDataCursor ids(_ids);
         int numDeleted = 0;
         for ( int i = 0; i < n; i++ ) {
-            if ( eraseCursorGlobalIfAuthorized(txn, ids.readLEAndAdvance<int64_t>()))
+            if ( eraseCursorGlobalIfAuthorized(txn, ids.readAndAdvance<LittleEndian<int64_t>>()))
                 numDeleted++;
             if ( inShutdown() )
                 break;
diff --git a/src/mongo/db/dbmessage.cpp b/src/mongo/db/dbmessage.cpp
index 95593ab545a..2dbbce7704a 100644
--- a/src/mongo/db/dbmessage.cpp
+++ b/src/mongo/db/dbmessage.cpp
@@ -103,7 +103,7 @@ namespace mongo {
         const char* p = _nsStart + _nsLen + 1;
         checkRead<int>(p, 2);
 
-        return ConstDataView(p).readLE<int32_t>(sizeof(int32_t));
+        return ConstDataView(p).read<LittleEndian<int32_t>>(sizeof(int32_t));
     }
 
     int DbMessage::pullInt() {
@@ -161,7 +161,7 @@ namespace mongo {
     T DbMessage::read() const {
         checkRead<T>(_nextjsobj, 1);
 
-        return ConstDataView(_nextjsobj).readLE<T>();
+        return ConstDataView(_nextjsobj).read<LittleEndian<T>>();
     }
 
     template<typename T> T DbMessage::readAndAdvance() {
diff --git a/src/mongo/db/dbmessage.h b/src/mongo/db/dbmessage.h
index 85d4ed731b4..78da93956c2 100644
--- a/src/mongo/db/dbmessage.h
+++ b/src/mongo/db/dbmessage.h
@@ -116,15 +116,15 @@ namespace mongo {
             }
 
             int64_t getCursorId() const {
-                return storage().readLE<int64_t>(offsetof(Layout, cursorId));
+                return storage().read<LittleEndian<int64_t>>(offsetof(Layout, cursorId));
             }
 
             int32_t getStartingFrom() const {
-                return storage().readLE<int32_t>(offsetof(Layout, startingFrom));
+                return storage().read<LittleEndian<int32_t>>(offsetof(Layout, startingFrom));
             }
 
             int32_t getNReturned() const {
-                return storage().readLE<int32_t>(offsetof(Layout, nReturned));
+                return storage().read<LittleEndian<int32_t>>(offsetof(Layout, nReturned));
             }
 
             const char* data() const {
@@ -155,23 +155,23 @@ namespace mongo {
             }
 
             void setCursorId(int64_t value) {
-                storage().writeLE(value, offsetof(Layout, cursorId));
+                storage().write(tagLittleEndian(value), offsetof(Layout, cursorId));
             }
 
             void setStartingFrom(int32_t value) {
-                storage().writeLE(value, offsetof(Layout, startingFrom));
+                storage().write(tagLittleEndian(value), offsetof(Layout, startingFrom));
             }
 
             void setNReturned(int32_t value) {
-                storage().writeLE(value, offsetof(Layout, nReturned));
+                storage().write(tagLittleEndian(value), offsetof(Layout, nReturned));
             }
 
             int32_t getResultFlags() {
-                return DataView(msgdata().data()).readLE<int32_t>();
+                return DataView(msgdata().data()).read<LittleEndian<int32_t>>();
             }
 
             void setResultFlags(int32_t value) {
-                DataView(msgdata().data()).writeLE(value);
+                DataView(msgdata().data()).write(tagLittleEndian(value));
             }
 
             void setResultFlagsToOk() {
@@ -298,7 +298,7 @@ namespace mongo {
             if ( d.moreJSObjs() ) {
                 fields = d.nextJsObj();
             }
-            queryOptions = DataView(d.msg().header().data()).readLE<int32_t>();
+            queryOptions = DataView(d.msg().header().data()).read<LittleEndian<int32_t>>();
         }
     };
 
diff --git a/src/mongo/db/instance.cpp b/src/mongo/db/instance.cpp
index c769b93d43d..4554866b796 100644
--- a/src/mongo/db/instance.cpp
+++ b/src/mongo/db/instance.cpp
@@ -308,7 +308,10 @@ namespace {
         // TODO: use OP_COMMAND here instead of constructing
         // a legacy OP_QUERY style command
         BufBuilder cmdMsgBuf;
-        cmdMsgBuf.appendNum(DataView(message.header().data()).readLE<int32_t>()); // flags
+
+        int32_t flags = DataView(message.header().data()).read<LittleEndian<int32_t>>();
+        cmdMsgBuf.appendNum(flags);
+
         cmdMsgBuf.appendStr(interposedNss.db(), false); // not including null byte
         cmdMsgBuf.appendStr(".$cmd");
         cmdMsgBuf.appendNum(0); // ntoskip
diff --git a/src/mongo/db/storage/key_string.cpp b/src/mongo/db/storage/key_string.cpp
index 2cd548aadf7..0df4a8d8096 100644
--- a/src/mongo/db/storage/key_string.cpp
+++ b/src/mongo/db/storage/key_string.cpp
@@ -181,7 +181,7 @@ namespace mongo {
 
         template <typename T> T readType(BufReader* reader, bool inverted) {
             // TODO for C++11 to static_assert that T is integral
-            T t = ConstDataView(static_cast<const char*>(reader->skip(sizeof(T)))).readNative<T>();
+            T t = ConstDataView(static_cast<const char*>(reader->skip(sizeof(T)))).read<T>();
             if (inverted)
                 return ~t;
             return t;