SERVER-33032 add a DatabaseShardingState containing the databaseVersion as a decoration on Database

1 files changed, 85 insertions, 0 deletions

diff --git a/src/mongo/db/s/database_sharding_state.cpp b/src/mongo/db/s/database_sharding_state.cpp
new file mode 100644
index 00000000000..40a630bc5b4
--- /dev/null
+++ b/src/mongo/db/s/database_sharding_state.cpp
@@ -0,0 +1,85 @@
+/**
+ *    Copyright (C) 2018 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.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/s/database_sharding_state.h"
+
+#include "mongo/db/operation_context.h"
+
+namespace mongo {
+const Database::Decoration<DatabaseShardingState> DatabaseShardingState::get =
+    Database::declareDecorationWithOwner<DatabaseShardingState>();
+
+DatabaseShardingState::DatabaseShardingState(Database* db) : _db(db) {}
+
+void DatabaseShardingState::enterCriticalSection(OperationContext* opCtx) {
+    invariant(opCtx->lockState()->isDbLockedForMode(_db->name(), MODE_X));
+    invariant(!_critSecSignal);
+    _critSecSignal = std::make_shared<Notification<void>>();
+    // TODO (SERVER-33313): call CursorManager::invalidateAll() on all collections in this database
+    // with 'fromMovePrimary=true' and a predicate to only invalidate the cursor if the opCtx on its
+    // PlanExecutor has a client dbVersion.
+}
+
+void DatabaseShardingState::exitCriticalSection(OperationContext* opCtx,
+                                                boost::optional<DatabaseVersion> newDbVersion) {
+    invariant(opCtx->lockState()->isDbLockedForMode(_db->name(), MODE_X));
+    invariant(_critSecSignal);
+    _critSecSignal->set();
+    _critSecSignal.reset();
+    _dbVersion = newDbVersion;
+}
+
+std::shared_ptr<Notification<void>> DatabaseShardingState::getCriticalSectionSignal() const {
+    return _critSecSignal;
+}
+
+void DatabaseShardingState::setDbVersion(OperationContext* opCtx,
+                                         boost::optional<DatabaseVersion> newDbVersion) {
+    invariant(opCtx->lockState()->isDbLockedForMode(_db->name(), MODE_X));
+    _dbVersion = newDbVersion;
+}
+
+void DatabaseShardingState::checkDbVersion(OperationContext* opCtx) const {
+    invariant(opCtx->lockState()->isLocked());
+
+    if (_critSecSignal) {
+        // TODO (SERVER-33097): Set movePrimary critical section signal on the
+        // OperationShardingState (so that the operation can wait outside the DBLock for the
+        // movePrimary critical section to end before returning to the client).
+
+        // TODO (SERVER-33098): throw StaleDbVersion.
+    }
+
+    // TODO (SERVER-33098): check the client's dbVersion (from the OperationShardingState) against
+    // _dbVersion, and throw StaleDbVersion if they don't match.
+    return;
+}
+
+}  // namespace mongo