SERVER-10471 Fleshing out the new query planner / enumerator

1 files changed, 92 insertions, 0 deletions

diff --git a/src/mongo/db/query/interval.h b/src/mongo/db/query/interval.h
new file mode 100644
index 00000000000..f726748773b
--- /dev/null
+++ b/src/mongo/db/query/interval.h
@@ -0,0 +1,92 @@
+/**
+ *    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/>.
+ */
+
+#pragma once
+
+#include "mongo/db/jsobj.h"
+
+namespace mongo {
+
+    /** A range of values for one field. */
+    struct Interval {
+
+        // No BSONValue means we have to keep a BSONObj and pointers (BSONElement) into it.
+        // 'start' may not point at the first field in _intervalData.
+        // 'end' may not point at the last field in _intervalData.
+        // 'start' and 'end' may point at the same field.
+        BSONObj _intervalData;
+
+        // Start and End must be ordered according to the index order.
+        BSONElement start;
+        bool startInclusive;
+
+        BSONElement end;
+        bool endInclusive;
+
+        /** Creates an empty interval */
+        Interval();
+
+        /**
+         * Creates an interval that starts at the first field of 'base' and ends at the second
+         * field of 'base'. (In other words, 'base' is a bsonobj with at least two elements, of
+         * which we don't care about field names.)
+         *
+         * The interval's extremities are closed or not depending on whether
+         * 'start'/'endIncluded' are true or not.
+         */
+        Interval(BSONObj base, bool startIncluded, bool endInclued);
+
+        /** Sets the current interval to the given values (see constructor) */
+        void init(BSONObj base, bool startIncluded, bool endIncluded);
+
+        /** Returns true if an empty-constructed interval hasn't been init()-ialized yet */
+        bool isEmpty() const;
+
+        /** Returns how 'this' compares to 'other' */
+        enum IntervalComparison {
+            // There is some intersection.
+            INTERVAL_EQUALS,
+            INTERVAL_CONTAINS,
+            INTERVAL_WITHIN,
+            INTERVAL_OVERLAPS_BEFORE,
+            INTERVAL_OVERLAPS_AFTER,
+
+            // There is no intersection.
+            INTERVAL_PRECEDES,
+            INTERVAL_SUCCEDS,
+
+            INTERVAL_UNKNOWN
+        };
+        IntervalComparison compare(const Interval& other) const;
+
+        /**
+         * Updates 'this' with the intersection of 'this' and 'other'. If 'this' and 'other'
+         * have been compare()d before, that result can be optionally passed in 'cmp'
+         */
+        void intersect(const Interval& other, IntervalComparison cmp = INTERVAL_UNKNOWN);
+
+        /**
+         * Updates 'this" with the union of 'this' and 'other'. If 'this' and 'other' have
+         * been compare()d before, that result can be optionaly passed in 'cmp'.
+         */
+        void combine(const Interval& other, IntervalComparison cmp = INTERVAL_UNKNOWN);
+    };
+
+    inline bool operator==(const Interval& lhs, const Interval& rhs) {
+        return lhs.compare(rhs) == Interval::INTERVAL_EQUALS;
+    }
+
+} // namespace mongo