SERVER-24631: Add TTL collection namespace cache

1 files changed, 56 insertions, 0 deletions

diff --git a/src/mongo/db/ttl_collection_cache.h b/src/mongo/db/ttl_collection_cache.h
new file mode 100644
index 00000000000..a909947b069
--- /dev/null
+++ b/src/mongo/db/ttl_collection_cache.h
@@ -0,0 +1,56 @@
+/**
+ * Copyright (C) 2016 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 <string>
+#include <vector>
+
+#include "mongo/db/namespace_string.h"
+#include "mongo/db/service_context.h"
+#include "mongo/stdx/mutex.h"
+
+/**
+ * Caches the set of collections containing a TTL index.
+ * This class is thread safe.
+ */
+namespace mongo {
+
+class TTLCollectionCache {
+public:
+    static TTLCollectionCache& get(ServiceContext* ctx);
+    // Caller is responsible for ensuring no duplicates are registered.
+    void registerCollection(const NamespaceString& collectionNS);
+    void unregisterCollection(const NamespaceString& collectionNS);
+    std::vector<std::string> getCollections();
+
+private:
+    std::vector<std::string> _ttlCollections;
+    stdx::mutex _ttlCollectionsLock;
+};
+}  // namespace mongo