Remove outdated references to $unwind as an expression rather than a source

Author: RedBeard0531

src/mongo/db/pipeline/expression.cpp

@@ -34,17 +34,9 @@ namespace mongo {
         verify(false && "Expression::toMatcherBson()");
     }
 
-    Expression::ObjectCtx::ObjectCtx(int theOptions):
-        options(theOptions),
-        unwindField() {
-    }
-
-    void Expression::ObjectCtx::unwind(string fieldName) {
-        verify(unwindOk());
-        verify(!unwindUsed());
-        verify(fieldName.size());
-        unwindField = fieldName;
-    }
+    Expression::ObjectCtx::ObjectCtx(int theOptions)
+        : options(theOptions)
+    {}
 
     bool Expression::ObjectCtx::documentOk() const {
         return ((options & DOCUMENT_OK) != 0);
@@ -54,8 +46,6 @@ namespace mongo {
         return ((options & TOP_LEVEL) != 0);
     }
 
-    const char Expression::unwindName[] = "$unwind";
-
     string Expression::removeFieldPrefix(const string &prefixedField) {
         const char *pPrefixedField = prefixedField.c_str();
         uassert(15982, str::stream() <<
@@ -72,11 +62,6 @@ namespace mongo {
 
           f0: {f1: ..., f2: ..., f3: ...}
           f0: {$operator:[operand1, operand2, ...]}
-          f0: {$unwind:"fieldpath"}
-
-          We handle $unwind as a special case, because this is done by the
-          projection source.  For any other expression, we hand over control to
-          code that parses the expression and returns an expression.
         */
 
         intrusive_ptr<Expression> pExpression; // the result

src/mongo/db/pipeline/expression.h

@@ -133,32 +133,20 @@ namespace mongo {
         /*
           Utility class for parseObject() below.
 
-          Only one array can be unwound in a processing pipeline.  If the
-          UNWIND_OK option is used, unwindOk() will return true, and a field
-          can be declared as unwound using unwind(), after which unwindUsed()
-          will return true.  Only specify UNWIND_OK if it is OK to unwind an
-          array in the current context.
-
           DOCUMENT_OK indicates that it is OK to use a Document in the current
           context.
          */
         class ObjectCtx {
         public:
             ObjectCtx(int options);
-            static const int UNWIND_OK = 0x0001;
-            static const int DOCUMENT_OK = 0x0002;
-            static const int TOP_LEVEL = 0x0004;
-
-            bool unwindOk() const;
-            bool unwindUsed() const;
-            void unwind(string fieldName);
+            static const int DOCUMENT_OK = 0x0001;
+            static const int TOP_LEVEL = 0x0002;
 
             bool documentOk() const;
             bool topLevel() const;
 
         private:
             int options;
-            string unwindField;
         };
 
         /*
@@ -172,8 +160,6 @@ namespace mongo {
         static intrusive_ptr<Expression> parseObject(
             BSONElement *pBsonElement, ObjectCtx *pCtx);
 
-        static const char unwindName[];
-
         /*
           Parse a BSONElement Object which has already been determined to be
           functional expression.
@@ -1222,14 +1208,6 @@ namespace mongo {
 
 namespace mongo {
 
-    inline bool Expression::ObjectCtx::unwindOk() const {
-        return ((options & UNWIND_OK) != 0);
-    }
-
-    inline bool Expression::ObjectCtx::unwindUsed() const {
-        return (unwindField.size() != 0);
-    }
-
     inline int Expression::signum(int i) {
         if (i < 0)
             return -1;