Move remaining aggregation files from commands directory to pipeline

pipeline_command.cpp remains in commands because it contains the actual command

1 files changed, 62 insertions, 0 deletions

diff --git a/src/mongo/db/pipeline/pipeline_d.h b/src/mongo/db/pipeline/pipeline_d.h
new file mode 100755
index 00000000000..a514fe22fbc
--- /dev/null
+++ b/src/mongo/db/pipeline/pipeline_d.h
@@ -0,0 +1,62 @@
+/**
+ * Copyright 2012 (c) 10gen Inc.
+ *
+ * This program is free software: you can redistribute it and/or  modify
+ * it under the terms of the GNU Affero General Public License, version 3,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include "pch.h"
+
+namespace mongo {
+    class DocumentSourceCursor;
+    class Pipeline;
+
+    /*
+      PipelineD is an extension of the Pipeline class, but with additional
+      material that references symbols that are not available in mongos,
+      where the remainder of the Pipeline class also functions.  PipelineD
+      is a friend of Pipeline so that it can have equal access to Pipeline's
+      members.
+
+      See the friend declaration in Pipeline.
+     */
+    class PipelineD {
+    public:
+
+        /**
+           Create a Cursor wrapped in a DocumentSourceCursor, which is suitable
+           to be the first source for a pipeline to begin with.  This source
+           will feed the execution of the pipeline.
+
+           This method looks for early pipeline stages that can be folded into
+           the underlying cursor, and when a cursor can absorb those, they
+           are removed from the head of the pipeline.  For example, an
+           early match can be removed and replaced with a Cursor that will
+           do an index scan.
+
+           @param pPipeline the logical "this" for this operation
+           @param dbName the name of the database
+           @param pExpCtx the expression context for this pipeline
+           @returns the cursor that was created
+         */
+        static intrusive_ptr<DocumentSourceCursor> prepareCursorSource(
+            const intrusive_ptr<Pipeline> &pPipeline,
+            const string &dbName,
+            const intrusive_ptr<ExpressionContext> &pExpCtx);
+
+    private:
+        PipelineD(); // does not exist:  prevent instantiation
+    };
+
+} // namespace mongo