SERVER-19596 Remove implicit circlular dependency in s2_keys

1 files changed, 82 insertions, 0 deletions

diff --git a/src/mongo/db/index/s2_common.h b/src/mongo/db/index/s2_common.h
new file mode 100644
index 00000000000..10632e3cb84
--- /dev/null
+++ b/src/mongo/db/index/s2_common.h
@@ -0,0 +1,82 @@
+/**
+*    Copyright (C) 2015 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 <string>
+
+#include "mongo/db/jsobj.h"
+
+class S2CellId;
+class S2RegionCoverer;
+
+namespace mongo {
+
+class GeometryContainer;
+
+// An enum describing the version of an S2 index.
+enum S2IndexVersion {
+    // The first version of the S2 index, introduced in MongoDB 2.4.0.  Compatible with MongoDB
+    // 2.4.0 and later.  Supports the following GeoJSON objects: Point, LineString, Polygon.
+    S2_INDEX_VERSION_1 = 1,
+
+    // The second version of the S2 index, introduced in MongoDB 2.6.0.  Compatible with
+    // MongoDB 2.6.0 and later.  Introduced support for the following GeoJSON objects:
+    // MultiPoint, MultiLineString, MultiPolygon, GeometryCollection.
+    S2_INDEX_VERSION_2 = 2,
+
+    // The third version of the S2 index, introduced in MongoDB 3.2.0. Introduced
+    // performance improvements and changed the key type from string to numeric
+    S2_INDEX_VERSION_3 = 3
+};
+
+struct S2IndexingParams {
+    // Since we take the cartesian product when we generate keys for an insert,
+    // we need a cap.
+    std::size_t maxKeysPerInsert;
+    // This is really an advisory parameter that we pass to the cover generator.  The
+    // finest/coarsest index level determine the required # of cells.
+    int maxCellsInCovering;
+    // What's the finest grained level that we'll index for non-points?
+    int finestIndexedLevel;
+    // And, what's the coarsest for non-points?  When we search in larger coverings
+    // we know we can stop here -- we index nothing coarser than this.
+    int coarsestIndexedLevel;
+    // Version of this index (specific to the index type).
+    S2IndexVersion indexVersion;
+    // Radius of the earth in meters
+    double radius;
+
+    std::string toString() const;
+
+    void configureCoverer(const GeometryContainer& geoContainer, S2RegionCoverer* coverer) const;
+};
+
+BSONObj S2CellIdToIndexKey(const S2CellId& cellId, S2IndexVersion indexVersion);
+
+}  // namespace mongo