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diff --git a/src/mongo/db/catalog/views_for_database.h b/src/mongo/db/catalog/views_for_database.h
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+/**
+ *    Copyright (C) 2018-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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 <functional>
+
+#include "mongo/db/operation_context.h"
+#include "mongo/db/query/collation/collator_factory_interface.h"
+#include "mongo/db/views/durable_view_catalog.h"
+#include "mongo/db/views/view.h"
+#include "mongo/db/views/view_graph.h"
+#include "mongo/stdx/unordered_map.h"
+#include "mongo/util/string_map.h"
+
+namespace mongo {
+
+/**
+ * Holds all data for the views associated with a particular database.
+ */
+class ViewsForDatabase {
+public:
+    using ViewMap = StringMap<std::shared_ptr<ViewDefinition>>;
+    using PipelineValidatorFn = std::function<StatusWith<stdx::unordered_set<NamespaceString>>(
+        OperationContext*, const ViewDefinition&)>;
+
+    /**
+     * Usage statistics about the views associated with a single database.
+     * Total views = internal + userViews + userTimeseries.
+     */
+    struct Stats {
+        int userViews = 0;
+        int userTimeseries = 0;
+        int internal = 0;
+    };
+
+    /**
+     * Helper method to build a collator from its spec.
+     */
+    static StatusWith<std::unique_ptr<CollatorInterface>> parseCollator(OperationContext* opCtx,
+                                                                        BSONObj collationSpec);
+
+    std::shared_ptr<DurableViewCatalog> durable;
+    ViewMap viewMap;
+    bool valid = false;
+    ViewGraph viewGraph;
+    bool viewGraphNeedsRefresh = true;
+    Stats stats;
+    bool ignoreExternalChange = false;
+
+    /**
+     * uasserts with the InvalidViewDefinition error if the current in-memory state of the views for
+     * this database is invalid which can happen as a result of direct writes to the 'system.views'
+     * collection or data corruption. This prevents further use of views on this database until the
+     * issue is resolved.
+     */
+    void requireValidCatalog() const;
+
+    /**
+     * Returns the 'ViewDefiniton' assocated with namespace 'ns' if one exists, nullptr otherwise.
+     */
+    std::shared_ptr<const ViewDefinition> lookup(const NamespaceString& ns) const;
+
+    /**
+     * Reloads the views for this database by iterating the DurableViewCatalog.
+     */
+    Status reload(OperationContext* opCtx);
+
+    /**
+     * Returns Status::OK if each view namespace in 'refs' has the same default collation as
+     * 'view'. Otherwise, returns ErrorCodes::OptionNotSupportedOnView.
+     */
+    Status validateCollation(OperationContext* opCtx,
+                             const ViewDefinition& view,
+                             const std::vector<NamespaceString>& refs) const;
+
+    /**
+     * Parses the view definition pipeline, attempts to upsert into the view graph, and
+     * refreshes the graph if necessary. Returns an error status if the resulting graph
+     * would be invalid.
+     */
+    Status upsertIntoGraph(OperationContext* opCtx,
+                           const ViewDefinition& viewDef,
+                           const PipelineValidatorFn&);
+};
+
+}  // namespace mongo