SERVER-10026 break planner into four pieces

1 files changed, 159 insertions, 0 deletions

diff --git a/src/mongo/db/query/planner_access.h b/src/mongo/db/query/planner_access.h
new file mode 100644
index 00000000000..ce3cb10d73a
--- /dev/null
+++ b/src/mongo/db/query/planner_access.h
@@ -0,0 +1,159 @@
+/**
+ *    Copyright (C) 2013 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/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include "mongo/db/query/canonical_query.h"
+#include "mongo/db/query/query_planner_params.h"
+#include "mongo/db/query/query_solution.h"
+
+namespace mongo {
+
+    /**
+     * Methods for creating a QuerySolutionNode tree that accesses the data required by the query.
+     */
+    class QueryPlannerAccess {
+    public:
+        /**
+         * Return a CollectionScanNode that scans as requested in 'query'.
+         */
+        static QuerySolutionNode* makeCollectionScan(const CanonicalQuery& query,
+                                                     bool tailable,
+                                                     const QueryPlannerParams& params);
+
+        /**
+         * Return a plan that uses the provided index as a proxy for a collection scan.
+         */
+        static QuerySolutionNode* scanWholeIndex(const IndexEntry& index,
+                                                 const CanonicalQuery& query,
+                                                 const QueryPlannerParams& params,
+                                                 int direction = 1);
+
+        //
+        // Indexed Data Access methods.
+        //
+        // The inArrayOperator flag deserves some attention.  It is set when we're processing a child of
+        // a MatchExpression::ALL or MatchExpression::ELEM_MATCH_OBJECT.
+        //
+        // When true, the following behavior changes for all methods below that take it as an argument:
+        // 0. No deletion of MatchExpression(s).  In fact,
+        // 1. No mutation of the MatchExpression at all.  We need the tree as-is in order to perform
+        //    a filter on the entire tree.
+        // 2. No fetches performed.  There will be a final fetch by the caller of buildIndexedDataAccess
+        //    who set the value of inArrayOperator to true.
+        // 3. No compound indices are used and no bounds are combined.  These are incorrect in the context
+        //    of these operators.
+        //
+
+        /**
+         * If 'inArrayOperator' is false, takes ownership of 'root'.
+         */
+        static QuerySolutionNode* buildIndexedDataAccess(const CanonicalQuery& query,
+                                                         MatchExpression* root,
+                                                         bool inArrayOperator,
+                                                         const vector<IndexEntry>& indices);
+
+        /**
+         * Takes ownership of 'root'.
+         */
+        static QuerySolutionNode* buildIndexedAnd(const CanonicalQuery& query,
+                                                  MatchExpression* root,
+                                                  bool inArrayOperator,
+                                                  const vector<IndexEntry>& indices);
+
+        /**
+         * Takes ownership of 'root'.
+         */
+        static QuerySolutionNode* buildIndexedOr(const CanonicalQuery& query,
+                                                 MatchExpression* root,
+                                                 bool inArrayOperator,
+                                                 const vector<IndexEntry>& indices);
+
+        /**
+         * Helper used by buildIndexedAnd and buildIndexedOr.
+         *
+         * The children of AND and OR nodes are sorted by the index that the subtree rooted at
+         * that node uses.  Child nodes that use the same index are adjacent to one another to
+         * facilitate grouping of index scans.  As such, the processing for AND and OR is
+         * almost identical.
+         *
+         * See tagForSort and sortUsingTags in index_tag.h for details on ordering the children
+         * of OR and AND.
+         *
+         * Does not take ownership of 'root' but may remove children from it.
+         */
+        static bool processIndexScans(const CanonicalQuery& query,
+                                      MatchExpression* root,
+                                      bool inArrayOperator,
+                                      const vector<IndexEntry>& indices,
+                                      vector<QuerySolutionNode*>* out);
+
+        //
+        // Helpers for creating an index scan.
+        //
+
+        /**
+         * Create a new data access node.
+         *
+         * If the node is an index scan, the bounds for 'expr' are computed and placed into the
+         * first field's OIL position.  The rest of the OILs are allocated but uninitialized.
+         *
+         * If the node is a geo node, grab the geo data from 'expr' and stuff it into the
+         * geo solution node of the appropriate type.
+         */
+        static QuerySolutionNode* makeLeafNode(const IndexEntry& index,
+                                               MatchExpression* expr,
+                                               bool* exact);
+
+        /**
+         * Merge the predicate 'expr' with the leaf node 'node'.
+         */
+        static void mergeWithLeafNode(MatchExpression* expr,
+                                      const IndexEntry& index,
+                                      size_t pos,
+                                      bool* exactOut,
+                                      QuerySolutionNode* node,
+                                      MatchExpression::MatchType mergeType);
+
+        /**
+         * If index scan (regular or expression index), fill in any bounds that are missing in
+         * 'node' with the "all values for this field" interval.
+         *
+         * If geo, do nothing.
+         */
+        static void finishLeafNode(QuerySolutionNode* node, const IndexEntry& index);
+
+        /**
+         * Assumes each OIL in bounds is increasing.
+         *
+         * Aligns OILs (and bounds) according to the kp direction * the scanDir.
+         */
+        static void alignBounds(IndexBounds* bounds, const BSONObj& kp, int scanDir = 1);
+    };
+
+}  // namespace mongo