SERVER-38700 unshim Database

10 files changed, 72 insertions, 382 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 3cfdc818fbb..76ac4282555 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -698,7 +698,6 @@ env.Library(
         '$BUILD_DIR/mongo/idl/idl_parser',
         'catalog/collection',
         'catalog/database_holder',
-        'catalog/database',
         'catalog/uuid_catalog',
         'commands/test_commands_enabled',
         'commands/txn_cmd_request',
@@ -1032,7 +1031,6 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/db/catalog/collection',
-        '$BUILD_DIR/mongo/db/catalog/database',
         'rw_concern_d',
         'background',
         'logical_clock',
@@ -1146,7 +1144,6 @@ env.Library(
         'background',
         'bson/dotted_path_support',
         'catalog/collection',
-        'catalog/database',
         'catalog/document_validation',
         'catalog/index_catalog_entry',
         'catalog/index_catalog',
diff --git a/src/mongo/db/catalog/SConscript b/src/mongo/db/catalog/SConscript
index 548e148f2cb..8a708417845 100644
--- a/src/mongo/db/catalog/SConscript
+++ b/src/mongo/db/catalog/SConscript
@@ -196,23 +196,12 @@ env.Library(
     ],
 )
 
-env.Library(
-    target='database',
-    source=[
-        "database.cpp",
-    ],
-    LIBDEPS=[
-        '$BUILD_DIR/mongo/base',
-    ],
-)
-
 env.CppUnitTest(
     target='database_test',
     source=[
         'database_test.cpp',
     ],
     LIBDEPS=[
-        'database',
         'multi_index_block',
         '$BUILD_DIR/mongo/db/auth/authmocks',
         '$BUILD_DIR/mongo/db/concurrency/lock_manager',
@@ -286,7 +275,6 @@ env.Library(
     ],
     LIBDEPS=[
         'collection',
-        'database',
         'database_holder',
         '$BUILD_DIR/mongo/base',
         '$BUILD_DIR/mongo/db/namespace_string',
@@ -337,7 +325,6 @@ env.Library(
     ],
     LIBDEPS_PRIVATE=[
         'collection',
-        'database',
         'uuid_catalog',
         '$BUILD_DIR/mongo/db/repair_database',
         '$BUILD_DIR/mongo/db/service_context',
@@ -372,7 +359,6 @@ env.Library(
     LIBDEPS=[
         'collection',
         'collection_options',
-        'database',
         'database_holder',
         'health_log',
         'index_catalog',
@@ -428,7 +414,6 @@ env.Library(
         '$BUILD_DIR/mongo/db/write_ops',
         'collection_options',
         'collection',
-        'database',
         'index_catalog',
         'index_key_validate',
         'multi_index_block',
diff --git a/src/mongo/db/catalog/database.cpp b/src/mongo/db/catalog/database.cpp
deleted file mode 100644
index 12ef918664b..00000000000
--- a/src/mongo/db/catalog/database.cpp
+++ /dev/null
@@ -1,43 +0,0 @@
-
-/**
- *    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.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/catalog/database.h"
-
-namespace mongo {
-
-Database::Impl::~Impl() = default;
-
-MONGO_DEFINE_SHIM(Database::makeImpl);
-
-void Database::TUHook::hook() noexcept {}
-
-}  // namespace mongo
diff --git a/src/mongo/db/catalog/database.h b/src/mongo/db/catalog/database.h
index ea77cdb9a20..74ff3b6f42b 100644
--- a/src/mongo/db/catalog/database.h
+++ b/src/mongo/db/catalog/database.h
@@ -33,7 +33,6 @@
 #include <memory>
 #include <string>
 
-#include "mongo/base/shim.h"
 #include "mongo/base/status.h"
 #include "mongo/base/string_data.h"
 #include "mongo/bson/bsonobj.h"
@@ -59,104 +58,17 @@ class Database : public Decorable<Database> {
 public:
     typedef StringMap<Collection*> CollectionMap;
 
-    class Impl {
-    public:
-        virtual ~Impl() = 0;
-
-        virtual void init(OperationContext* opCtx) = 0;
-
-        virtual void close(OperationContext* opCtx, const std::string& reason) = 0;
-
-        virtual const std::string& name() const = 0;
-
-        virtual void clearTmpCollections(OperationContext* opCtx) = 0;
-
-        virtual Status setProfilingLevel(OperationContext* opCtx, int newLevel) = 0;
-
-        virtual int getProfilingLevel() const = 0;
-
-        virtual const char* getProfilingNS() const = 0;
-
-        virtual void setDropPending(OperationContext* opCtx, bool dropPending) = 0;
-
-        virtual bool isDropPending(OperationContext* opCtx) const = 0;
-
-        virtual void getStats(OperationContext* opCtx, BSONObjBuilder* output, double scale) = 0;
-
-        virtual const DatabaseCatalogEntry* getDatabaseCatalogEntry() const = 0;
-
-        virtual Status dropCollection(OperationContext* opCtx,
-                                      StringData fullns,
-                                      repl::OpTime dropOpTime) = 0;
-        virtual Status dropCollectionEvenIfSystem(OperationContext* opCtx,
-                                                  const NamespaceString& fullns,
-                                                  repl::OpTime dropOpTime) = 0;
-
-        virtual Status dropView(OperationContext* opCtx, StringData fullns) = 0;
-
-        virtual Status userCreateNS(OperationContext* opCtx,
-                                    const NamespaceString& fullns,
-                                    CollectionOptions collectionOptions,
-                                    bool createDefaultIndexes,
-                                    const BSONObj& idIndex) = 0;
-
-        virtual Collection* createCollection(OperationContext* opCtx,
-                                             StringData ns,
-                                             const CollectionOptions& options,
-                                             bool createDefaultIndexes,
-                                             const BSONObj& idIndex) = 0;
-
-        virtual Status createView(OperationContext* opCtx,
-                                  StringData viewName,
-                                  const CollectionOptions& options) = 0;
-
-        virtual Collection* getCollection(OperationContext* opCtx, StringData ns) const = 0;
-
-        virtual ViewCatalog* getViewCatalog() = 0;
-
-        virtual Collection* getOrCreateCollection(OperationContext* opCtx,
-                                                  const NamespaceString& nss) = 0;
-
-        virtual Status renameCollection(OperationContext* opCtx,
-                                        StringData fromNS,
-                                        StringData toNS,
-                                        bool stayTemp) = 0;
-
-        virtual const std::string& getSystemViewsName() const = 0;
-
-        virtual StatusWith<NamespaceString> makeUniqueCollectionNamespace(
-            OperationContext* opCtx, StringData collectionNameModel) = 0;
-
-        virtual void checkForIdIndexesAndDropPendingCollections(OperationContext* opCtx) = 0;
-
-        virtual CollectionMap& collections() = 0;
-        virtual const CollectionMap& collections() const = 0;
-
-        virtual uint64_t epoch() const = 0;
-    };
-
-public:
     /**
      * Creates the namespace 'ns' in the database 'db' according to 'options'. If
      * 'createDefaultIndexes' is true, creates the _id index for the collection (and the system
      * indexes, in the case of system collections). Creates the collection's _id index according
      * to 'idIndex', if it is non-empty.  When 'idIndex' is empty, creates the default _id index.
      */
-    inline Status userCreateNS(OperationContext* opCtx,
-                               const NamespaceString& fullns,
-                               CollectionOptions collectionOptions,
-                               bool createDefaultIndexes = true,
-                               const BSONObj& idIndex = BSONObj()) {
-        return this->_impl().userCreateNS(
-            opCtx, fullns, std::move(collectionOptions), createDefaultIndexes, idIndex);
-    }
-
-    static MONGO_DECLARE_SHIM((Database * this_,
-                               StringData name,
-                               DatabaseCatalogEntry*,
-                               uint64_t epoch,
-                               PrivateTo<Database>)
-                                  ->std::unique_ptr<Impl>) makeImpl;
+    virtual Status userCreateNS(OperationContext* opCtx,
+                                const NamespaceString& fullns,
+                                CollectionOptions collectionOptions,
+                                bool createDefaultIndexes = true,
+                                const BSONObj& idIndex = BSONObj()) = 0;
 
     /**
      * Iterating over a Database yields Collection* pointers.
@@ -203,44 +115,28 @@ public:
         CollectionMap::const_iterator _it;
     };
 
-    explicit inline Database(const StringData name,
-                             DatabaseCatalogEntry* const dbEntry,
-                             uint64_t epoch)
-        : _pimpl(makeImpl(this, name, dbEntry, epoch, PrivateCall<Database>{})) {}
+    Database() = default;
 
     // must call close first
-    inline ~Database() = default;
+    virtual ~Database() = default;
 
     inline Database(Database&&) = delete;
     inline Database& operator=(Database&&) = delete;
 
-    inline iterator begin() const {
-        return iterator(this->_impl().collections().begin());
-    }
-
-    inline iterator end() const {
-        return iterator(this->_impl().collections().end());
-    }
+    virtual iterator begin() const = 0;
+    virtual iterator end() const = 0;
 
     /**
      * Sets up internal memory structures.
      */
-    inline void init(OperationContext* opCtx) {
-        this->_impl().init(opCtx);
-    }
+    virtual void init(OperationContext* opCtx) = 0;
 
     // closes files and other cleanup see below.
-    inline void close(OperationContext* const opCtx, const std::string& reason) {
-        return this->_impl().close(opCtx, reason);
-    }
+    virtual void close(OperationContext* const opCtx, const std::string& reason) = 0;
 
-    inline const std::string& name() const {
-        return this->_impl().name();
-    }
+    virtual const std::string& name() const = 0;
 
-    inline void clearTmpCollections(OperationContext* const opCtx) {
-        return this->_impl().clearTmpCollections(opCtx);
-    }
+    virtual void clearTmpCollections(OperationContext* const opCtx) = 0;
 
     /**
      * Sets a new profiling level for the database and returns the outcome.
@@ -248,17 +144,11 @@ public:
      * @param opCtx Operation context which to use for creating the profiling collection.
      * @param newLevel New profiling level to use.
      */
-    inline Status setProfilingLevel(OperationContext* const opCtx, const int newLevel) {
-        return this->_impl().setProfilingLevel(opCtx, newLevel);
-    }
+    virtual Status setProfilingLevel(OperationContext* const opCtx, const int newLevel) = 0;
 
-    inline int getProfilingLevel() const {
-        return this->_impl().getProfilingLevel();
-    }
+    virtual int getProfilingLevel() const = 0;
 
-    inline const char* getProfilingNS() const {
-        return this->_impl().getProfilingNS();
-    }
+    virtual const char* getProfilingNS() const = 0;
 
     /**
      * Sets the 'drop-pending' state of this Database.
@@ -268,27 +158,19 @@ public:
      * state.
      * The database must be locked in MODE_X when calling this function.
      */
-    inline void setDropPending(OperationContext* opCtx, bool dropPending) {
-        this->_impl().setDropPending(opCtx, dropPending);
-    }
+    virtual void setDropPending(OperationContext* opCtx, bool dropPending) = 0;
 
     /**
      * Returns the 'drop-pending' state of this Database.
      * The database must be locked in MODE_X when calling this function.
      */
-    inline bool isDropPending(OperationContext* opCtx) const {
-        return this->_impl().isDropPending(opCtx);
-    }
+    virtual bool isDropPending(OperationContext* opCtx) const = 0;
 
-    inline void getStats(OperationContext* const opCtx,
-                         BSONObjBuilder* const output,
-                         const double scale = 1) {
-        return this->_impl().getStats(opCtx, output, scale);
-    }
+    virtual void getStats(OperationContext* const opCtx,
+                          BSONObjBuilder* const output,
+                          const double scale = 1) = 0;
 
-    inline const DatabaseCatalogEntry* getDatabaseCatalogEntry() const {
-        return this->_impl().getDatabaseCatalogEntry();
-    }
+    virtual const DatabaseCatalogEntry* getDatabaseCatalogEntry() const = 0;
 
     /**
      * dropCollection() will refuse to drop system collections. Use dropCollectionEvenIfSystem() if
@@ -297,69 +179,47 @@ public:
      * If we are applying a 'drop' oplog entry on a secondary, 'dropOpTime' will contain the optime
      * of the oplog entry.
      */
-    inline Status dropCollection(OperationContext* const opCtx,
-                                 const StringData fullns,
-                                 repl::OpTime dropOpTime = {}) {
-        return this->_impl().dropCollection(opCtx, fullns, dropOpTime);
-    }
-    inline Status dropCollectionEvenIfSystem(OperationContext* const opCtx,
-                                             const NamespaceString& fullns,
-                                             repl::OpTime dropOpTime = {}) {
-        return this->_impl().dropCollectionEvenIfSystem(opCtx, fullns, dropOpTime);
-    }
-
-    inline Status dropView(OperationContext* const opCtx, const StringData fullns) {
-        return this->_impl().dropView(opCtx, fullns);
-    }
-
-    inline Collection* createCollection(OperationContext* const opCtx,
-                                        StringData ns,
-                                        const CollectionOptions& options = CollectionOptions(),
-                                        const bool createDefaultIndexes = true,
-                                        const BSONObj& idIndex = BSONObj()) {
-        return this->_impl().createCollection(opCtx, ns, options, createDefaultIndexes, idIndex);
-    }
-
-    inline Status createView(OperationContext* const opCtx,
-                             const StringData viewName,
-                             const CollectionOptions& options) {
-        return this->_impl().createView(opCtx, viewName, options);
-    }
+    virtual Status dropCollection(OperationContext* const opCtx,
+                                  const StringData fullns,
+                                  repl::OpTime dropOpTime = {}) = 0;
+    virtual Status dropCollectionEvenIfSystem(OperationContext* const opCtx,
+                                              const NamespaceString& fullns,
+                                              repl::OpTime dropOpTime = {}) = 0;
+
+    virtual Status dropView(OperationContext* const opCtx, const StringData fullns) = 0;
+
+    virtual Collection* createCollection(OperationContext* const opCtx,
+                                         StringData ns,
+                                         const CollectionOptions& options = CollectionOptions(),
+                                         const bool createDefaultIndexes = true,
+                                         const BSONObj& idIndex = BSONObj()) = 0;
+
+    virtual Status createView(OperationContext* const opCtx,
+                              const StringData viewName,
+                              const CollectionOptions& options) = 0;
 
     /**
      * @param ns - this is fully qualified, which is maybe not ideal ???
      */
-    inline Collection* getCollection(OperationContext* opCtx, const StringData ns) const {
-        return this->_impl().getCollection(opCtx, ns);
-    }
+    virtual Collection* getCollection(OperationContext* opCtx, const StringData ns) const = 0;
 
-    inline Collection* getCollection(OperationContext* opCtx, const NamespaceString& ns) const {
-        return this->_impl().getCollection(opCtx, ns.ns());
-    }
+    virtual Collection* getCollection(OperationContext* opCtx, const NamespaceString& ns) const = 0;
 
     /**
      * Get the view catalog, which holds the definition for all views created on this database. You
      * must be holding a database lock to use this accessor.
      */
-    inline ViewCatalog* getViewCatalog() {
-        return this->_impl().getViewCatalog();
-    }
-
-    inline Collection* getOrCreateCollection(OperationContext* const opCtx,
-                                             const NamespaceString& nss) {
-        return this->_impl().getOrCreateCollection(opCtx, nss);
-    }
-
-    inline Status renameCollection(OperationContext* const opCtx,
-                                   const StringData fromNS,
-                                   const StringData toNS,
-                                   const bool stayTemp) {
-        return this->_impl().renameCollection(opCtx, fromNS, toNS, stayTemp);
-    }
-
-    inline const std::string& getSystemViewsName() const {
-        return this->_impl().getSystemViewsName();
-    }
+    virtual ViewCatalog* getViewCatalog() = 0;
+
+    virtual Collection* getOrCreateCollection(OperationContext* const opCtx,
+                                              const NamespaceString& nss) = 0;
+
+    virtual Status renameCollection(OperationContext* const opCtx,
+                                    const StringData fromNS,
+                                    const StringData toNS,
+                                    const bool stayTemp) = 0;
+
+    virtual const std::string& getSystemViewsName() const = 0;
 
     /**
      * Generates a collection namespace suitable for creating a temporary collection.
@@ -371,19 +231,15 @@ public:
      *
      * The database must be locked in MODE_X when calling this function.
      */
-    inline StatusWith<NamespaceString> makeUniqueCollectionNamespace(
-        OperationContext* opCtx, StringData collectionNameModel) {
-        return this->_impl().makeUniqueCollectionNamespace(opCtx, collectionNameModel);
-    }
+    virtual StatusWith<NamespaceString> makeUniqueCollectionNamespace(
+        OperationContext* opCtx, StringData collectionNameModel) = 0;
 
     /**
      * If we are in a replset, every replicated collection must have an _id index.  As we scan each
      * database, we also gather a list of drop-pending collection namespaces for the
      * DropPendingCollectionReaper to clean up eventually.
      */
-    inline void checkForIdIndexesAndDropPendingCollections(OperationContext* opCtx) {
-        return this->_impl().checkForIdIndexesAndDropPendingCollections(opCtx);
-    }
+    virtual void checkForIdIndexesAndDropPendingCollections(OperationContext* opCtx) = 0;
 
     /**
      * A database is assigned a new epoch whenever it is closed and re-opened. This involves
@@ -396,33 +252,7 @@ public:
      * For example, closing a database must kill all active queries against the database. This is
      * implemented by checking that the epoch has not changed during query yield recovery.
      */
-    inline uint64_t epoch() const {
-        return this->_impl().epoch();
-    }
-
-private:
-    // This structure exists to give us a customization point to decide how to force users of this
-    // class to depend upon the corresponding `database.cpp` Translation Unit (TU).  All public
-    // forwarding functions call `_impl(), and `_impl` creates an instance of this structure.
-    struct TUHook {
-        static void hook() noexcept;
-
-        explicit inline TUHook() noexcept {
-            if (kDebugBuild)
-                this->hook();
-        }
-    };
-
-    inline const Impl& _impl() const {
-        TUHook{};
-        return *this->_pimpl;
-    }
-
-    inline Impl& _impl() {
-        TUHook{};
-        return *this->_pimpl;
-    }
-
-    std::unique_ptr<Impl> _pimpl;
+    virtual uint64_t epoch() const = 0;
 };
+
 }  // namespace mongo
diff --git a/src/mongo/db/catalog/database_holder_impl.cpp b/src/mongo/db/catalog/database_holder_impl.cpp
index 13992415498..660909b341e 100644
--- a/src/mongo/db/catalog/database_holder_impl.cpp
+++ b/src/mongo/db/catalog/database_holder_impl.cpp
@@ -37,8 +37,8 @@
 #include "mongo/db/audit.h"
 #include "mongo/db/background.h"
 #include "mongo/db/catalog/collection_impl.h"
-#include "mongo/db/catalog/database.h"
 #include "mongo/db/catalog/database_catalog_entry.h"
+#include "mongo/db/catalog/database_impl.h"
 #include "mongo/db/catalog/namespace_uuid_cache.h"
 #include "mongo/db/catalog/uuid_catalog.h"
 #include "mongo/db/concurrency/write_conflict_exception.h"
@@ -168,7 +168,7 @@ Database* DatabaseHolderImpl::openDb(OperationContext* opCtx, StringData ns, boo
             *justCreated = true;
     }
 
-    auto newDb = stdx::make_unique<Database>(dbname, entry, ++_epoch);
+    auto newDb = stdx::make_unique<DatabaseImpl>(dbname, entry, ++_epoch);
     newDb->init(opCtx);
 
     // Finally replace our nullptr entry with the new Database pointer.
diff --git a/src/mongo/db/catalog/database_impl.cpp b/src/mongo/db/catalog/database_impl.cpp
index 2ea1d12b612..eb869e6214a 100644
--- a/src/mongo/db/catalog/database_impl.cpp
+++ b/src/mongo/db/catalog/database_impl.cpp
@@ -80,15 +80,6 @@
 #include "mongo/util/log.h"
 
 namespace mongo {
-MONGO_REGISTER_SHIM(Database::makeImpl)
-(Database* const this_,
- const StringData name,
- DatabaseCatalogEntry* const dbEntry,
- uint64_t epoch,
- PrivateTo<Database>)
-    ->std::unique_ptr<Database::Impl> {
-    return stdx::make_unique<DatabaseImpl>(this_, name, dbEntry, epoch);
-}
 
 namespace {
 MONGO_FAIL_POINT_DEFINE(hangBeforeLoggingCreateCollection);
@@ -197,7 +188,7 @@ void DatabaseImpl::close(OperationContext* opCtx, const std::string& reason) {
     invariant(opCtx->lockState()->isW());
 
     // Clear cache of oplog Collection pointer.
-    repl::oplogCheckCloseDatabase(opCtx, this->_this);
+    repl::oplogCheckCloseDatabase(opCtx, this);
 
     for (auto&& pair : _collections) {
         auto* coll = pair.second;
@@ -272,8 +263,7 @@ Collection* DatabaseImpl::_getOrCreateCollectionInstance(OperationContext* opCtx
     return coll;
 }
 
-DatabaseImpl::DatabaseImpl(Database* const this_,
-                           const StringData name,
+DatabaseImpl::DatabaseImpl(const StringData name,
                            DatabaseCatalogEntry* const dbEntry,
                            uint64_t epoch)
     : _name(name.toString()),
@@ -281,9 +271,8 @@ DatabaseImpl::DatabaseImpl(Database* const this_,
       _epoch(epoch),
       _profileName(_name + ".system.profile"),
       _viewsName(_name + "." + DurableViewCatalog::viewsCollectionName().toString()),
-      _durableViews(DurableViewCatalogImpl(this_)),
-      _views(&_durableViews),
-      _this(this_) {}
+      _durableViews(DurableViewCatalogImpl(this)),
+      _views(&_durableViews) {}
 
 void DatabaseImpl::init(OperationContext* const opCtx) {
     Status status = validateDBName(_name);
@@ -370,7 +359,7 @@ Status DatabaseImpl::setProfilingLevel(OperationContext* opCtx, int newLevel) {
                       "the storage engine doesn't support profiling.");
     }
 
-    Status status = createProfileCollection(opCtx, this->_this);
+    Status status = createProfileCollection(opCtx, this);
 
     if (!status.isOK()) {
         return status;
diff --git a/src/mongo/db/catalog/database_impl.h b/src/mongo/db/catalog/database_impl.h
index 20cf3fb16e8..2130cdd9ce5 100644
--- a/src/mongo/db/catalog/database_impl.h
+++ b/src/mongo/db/catalog/database_impl.h
@@ -36,78 +36,15 @@
 
 namespace mongo {
 
-/**
- * Represents a logical database containing Collections.
- *
- * The semantics for a const Database are that you can mutate individual collections but not add or
- * remove them.
- */
-class DatabaseImpl : public Database::Impl {
+class DatabaseImpl : public Database {
 public:
-    typedef StringMap<Collection*> CollectionMap;
-
-    /**
-     * Iterating over a Database yields Collection* pointers.
-     */
-    class iterator {
-    public:
-        using iterator_category = std::forward_iterator_tag;
-        using value_type = Collection*;
-        using pointer = const value_type*;
-        using reference = const value_type&;
-        using difference_type = ptrdiff_t;
-
-        iterator() = default;
-        iterator(CollectionMap::const_iterator it) : _it(it) {}
-
-        reference operator*() const {
-            return _it->second;
-        }
-
-        pointer operator->() const {
-            return &_it->second;
-        }
-
-        bool operator==(const iterator& other) {
-            return _it == other._it;
-        }
-
-        bool operator!=(const iterator& other) {
-            return _it != other._it;
-        }
-
-        iterator& operator++() {
-            ++_it;
-            return *this;
-        }
-
-        iterator operator++(int) {
-            auto oldPosition = *this;
-            ++_it;
-            return oldPosition;
-        }
-
-    private:
-        CollectionMap::const_iterator _it;
-    };
-
-    explicit DatabaseImpl(Database* this_,
-                          StringData name,
-                          DatabaseCatalogEntry* dbEntry,
-                          uint64_t epoch);
+    explicit DatabaseImpl(StringData name, DatabaseCatalogEntry* dbEntry, uint64_t epoch);
 
     // must call close first
     ~DatabaseImpl();
 
     void init(OperationContext*) final;
 
-    iterator begin() const {
-        return iterator(_collections.begin());
-    }
-
-    iterator end() const {
-        return iterator(_collections.end());
-    }
 
     // closes files and other cleanup see below.
     void close(OperationContext* opCtx, const std::string& reason) final;
@@ -220,11 +157,12 @@ public:
 
     void checkForIdIndexesAndDropPendingCollections(OperationContext* opCtx) final;
 
-    inline CollectionMap& collections() final {
-        return _collections;
+    iterator begin() const final {
+        return iterator(_collections.begin());
     }
-    inline const CollectionMap& collections() const final {
-        return _collections;
+
+    iterator end() const final {
+        return iterator(_collections.end());
     }
 
     uint64_t epoch() const {
@@ -299,7 +237,6 @@ private:
 
     DurableViewCatalogImpl _durableViews;  // interface for system.views operations
     ViewCatalog _views;                    // in-memory representation of _durableViews
-    Database* _this;                       // Pointer to wrapper, for external caller compatibility.
 };
 
 }  // namespace mongo
diff --git a/src/mongo/db/commands/SConscript b/src/mongo/db/commands/SConscript
index b601794f389..eabb2df44fa 100644
--- a/src/mongo/db/commands/SConscript
+++ b/src/mongo/db/commands/SConscript
@@ -283,7 +283,6 @@ env.Library(
     LIBDEPS_PRIVATE=[
         '$BUILD_DIR/mongo/db/catalog/catalog_helpers',
         '$BUILD_DIR/mongo/db/catalog/collection',
-        '$BUILD_DIR/mongo/db/catalog/database',
         '$BUILD_DIR/mongo/db/commands',
         'test_commands_enabled',
     ],
diff --git a/src/mongo/db/matcher/SConscript b/src/mongo/db/matcher/SConscript
index 444c2b6739e..275b275569c 100644
--- a/src/mongo/db/matcher/SConscript
+++ b/src/mongo/db/matcher/SConscript
@@ -166,7 +166,6 @@ env.Library(
         '$BUILD_DIR/mongo/scripting/scripting_server',
         'expressions',
         '$BUILD_DIR/mongo/db/catalog/collection',
-        '$BUILD_DIR/mongo/db/catalog/database',
         '$BUILD_DIR/mongo/db/catalog/index_catalog',
         '$BUILD_DIR/mongo/db/catalog_raii',
     ],
diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 969e653c0a7..69ef7c36fb3 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -117,7 +117,6 @@ env.Library(
         'repl_coordinator_interface',
         '$BUILD_DIR/mongo/base',
         '$BUILD_DIR/mongo/db/background',
-        '$BUILD_DIR/mongo/db/catalog/database',
         '$BUILD_DIR/mongo/db/cloner',
         '$BUILD_DIR/mongo/db/concurrency/lock_manager',
         '$BUILD_DIR/mongo/db/db_raii',
@@ -212,7 +211,6 @@ env.Library(
         '$BUILD_DIR/mongo/base',
         '$BUILD_DIR/mongo/idl/idl_parser',
         '$BUILD_DIR/mongo/db/catalog/collection_options',
-        '$BUILD_DIR/mongo/db/catalog/database',
         '$BUILD_DIR/mongo/db/catalog/health_log',
         '$BUILD_DIR/mongo/db/db_raii',
     ],
@@ -485,7 +483,6 @@ env.Library(
         'oplog_interface_local.cpp',
     ],
     LIBDEPS=[
-        '$BUILD_DIR/mongo/db/catalog/database',
         '$BUILD_DIR/mongo/db/db_raii',
         '$BUILD_DIR/mongo/db/query_exec',
     ],