SERVER-14498 Add DeleteStage, rewrite DeleteExecutor to use it

1 files changed, 106 insertions, 0 deletions

diff --git a/src/mongo/db/exec/delete.h b/src/mongo/db/exec/delete.h
new file mode 100644
index 00000000000..3e24375a5dc
--- /dev/null
+++ b/src/mongo/db/exec/delete.h
@@ -0,0 +1,106 @@
+/**
+ *    Copyright (C) 2014 MongoDB 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/exec/plan_stage.h"
+#include "mongo/db/jsobj.h"
+
+namespace mongo {
+
+    class OperationContext;
+
+    struct DeleteStageParams {
+        DeleteStageParams() : isMulti(false), shouldCallLogOp(false) { }
+
+        // Should we delete all documents returned from the child (a "multi delete"), or at most one
+        // (a "single delete")?
+        bool isMulti;
+
+        // Should we write each delete to the oplog?
+        bool shouldCallLogOp;
+    };
+
+    /**
+     * This stage delete documents by DiskLoc that are returned from its child.  NEED_TIME
+     * is returned after deleting a document.
+     *
+     * Callers of work() must be holding a write lock (and, for shouldCallLogOp=true deletes,
+     * callers must have had the replication coordinator approve the write).
+     */
+    class DeleteStage : public PlanStage {
+        MONGO_DISALLOW_COPYING(DeleteStage);
+    public:
+        DeleteStage(OperationContext* txn,
+                    const DeleteStageParams& params,
+                    WorkingSet* ws,
+                    Collection* collection,
+                    PlanStage* child);
+        virtual ~DeleteStage();
+
+        virtual bool isEOF();
+        virtual StageState work(WorkingSetID* out);
+
+        virtual void saveState();
+        virtual void restoreState(OperationContext* opCtx);
+        virtual void invalidate(const DiskLoc& dl, InvalidationType type);
+
+        virtual std::vector<PlanStage*> getChildren() const;
+
+        virtual StageType stageType() const { return STAGE_DELETE; }
+
+        virtual PlanStageStats* getStats();
+
+        virtual const CommonStats* getCommonStats();
+
+        virtual const SpecificStats* getSpecificStats();
+
+        static const char* kStageType;
+
+    private:
+        // Transactional context.  Not owned by us.
+        OperationContext* _txn;
+
+        DeleteStageParams _params;
+
+        // Not owned by us.
+        WorkingSet* _ws;
+
+        // Collection to operate on.  Not owned by us.  Can be NULL (if NULL, isEOF() will always
+        // return true).  If non-NULL, the lifetime of the collection must supersede that of the
+        // stage.
+        Collection* _collection;
+
+        scoped_ptr<PlanStage> _child;
+
+        // Stats
+        CommonStats _commonStats;
+        DeleteStats _specificStats;
+    };
+
+}  // namespace mongo