From a79c8cfc2f3d778c9aa11d782b76adeec4624b37 Mon Sep 17 00:00:00 2001
From: Hari Khalsa <hkhalsa@10gen.com>
Date: Thu, 20 Mar 2014 14:57:34 -0400
Subject: SERVER-13292 fast path simple/fully covered projections

---
 src/mongo/db/exec/projection_exec.cpp | 36 +++++++++++++++++------------------
 1 file changed, 17 insertions(+), 19 deletions(-)

(limited to 'src/mongo/db/exec/projection_exec.cpp')

diff --git a/src/mongo/db/exec/projection_exec.cpp b/src/mongo/db/exec/projection_exec.cpp
index 15a224cbe72..afa60132631 100644
--- a/src/mongo/db/exec/projection_exec.cpp
+++ b/src/mongo/db/exec/projection_exec.cpp
@@ -249,7 +249,23 @@ namespace mongo {
         }
 
         BSONObjBuilder bob;
-        if (!requiresDocument()) {
+        if (member->hasObj()) {
+            MatchDetails matchDetails;
+
+            // If it's a positional projection we need a MatchDetails.
+            if (transformRequiresDetails()) {
+                matchDetails.requestElemMatchKey();
+                verify(NULL != _queryExpression);
+                verify(_queryExpression->matchesBSON(member->obj, &matchDetails));
+            }
+
+            Status projStatus = transform(member->obj, &bob, &matchDetails);
+            if (!projStatus.isOK()) {
+                return projStatus;
+            }
+        }
+        else {
+            verify(!requiresDocument());
             // Go field by field.
             if (_includeID) {
                 BSONElement elt;
@@ -273,24 +289,6 @@ namespace mongo {
                 }
             }
         }
-        else {
-            // Planner should have done this.
-            verify(member->hasObj());
-
-            MatchDetails matchDetails;
-
-            // If it's a positional projection we need a MatchDetails.
-            if (transformRequiresDetails()) {
-                matchDetails.requestElemMatchKey();
-                verify(NULL != _queryExpression);
-                verify(_queryExpression->matchesBSON(member->obj, &matchDetails));
-            }
-
-            Status projStatus = transform(member->obj, &bob, &matchDetails);
-            if (!projStatus.isOK()) {
-                return projStatus;
-            }
-        }
 
         for (MetaMap::const_iterator it = _meta.begin(); it != _meta.end(); ++it) {
             if (META_GEONEAR_DIST == it->second) {
-- 
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