SERVER-44806 Move DocumentSource::getNext() implementation to the header

src/mongo/db/pipeline/document_source.cpp

@@ -32,7 +32,6 @@
 #include "mongo/db/pipeline/document_source.h"
 
 #include "mongo/db/exec/document_value/value.h"
-#include "mongo/db/exec/scoped_timer.h"
 #include "mongo/db/matcher/expression_algo.h"
 #include "mongo/db/pipeline/document_source_group.h"
 #include "mongo/db/pipeline/document_source_internal_shard_filter.h"
@@ -87,21 +86,6 @@ list<intrusive_ptr<DocumentSource>> DocumentSource::parse(
     return it->second(stageSpec, expCtx);
 }
 
-DocumentSource::GetNextResult DocumentSource::getNext() {
-    pExpCtx->checkForInterrupt();
-    invariant(pExpCtx->opCtx->getServiceContext());
-    invariant(pExpCtx->opCtx->getServiceContext()->getFastClockSource());
-    ScopedTimer timer(pExpCtx->opCtx->getServiceContext()->getFastClockSource(),
-                      &_commonStats.executionTimeMillis);
-    ++_commonStats.works;
-
-    GetNextResult next = doGetNext();
-    if (next.isAdvanced()) {
-        ++_commonStats.advanced;
-    }
-    return next;
-}
-
 const char* DocumentSource::getSourceName() const {
     static const char unknown[] = "[UNKNOWN]";
     return unknown;

src/mongo/db/pipeline/document_source.h

@@ -46,6 +46,7 @@
 #include "mongo/db/exec/document_value/document.h"
 #include "mongo/db/exec/document_value/value.h"
 #include "mongo/db/exec/plan_stats.h"
+#include "mongo/db/exec/scoped_timer.h"
 #include "mongo/db/generic_cursor.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/db/namespace_string.h"
@@ -247,7 +248,22 @@ public:
      * return it) before asking for another result. Failing to do so can result in extra work, since
      * the Document/Value library must copy data on write when that data has a refcount above one.
      */
-    GetNextResult getNext();
+    GetNextResult getNext() {
+        pExpCtx->checkForInterrupt();
+        auto serviceCtx = pExpCtx->opCtx->getServiceContext();
+        invariant(serviceCtx);
+        auto fcs = serviceCtx->getFastClockSource();
+        invariant(fcs);
+
+        ScopedTimer timer(fcs, &_commonStats.executionTimeMillis);
+        ++_commonStats.works;
+
+        GetNextResult next = doGetNext();
+        if (next.isAdvanced()) {
+            ++_commonStats.advanced;
+        }
+        return next;
+    }
 
     /**
      * Returns a struct containing information about any special constraints imposed on using this