SERVER-32901 Consolidate sharding libraries

Also gets rid of most usages of the std::string variant of
CollectionShardingState::get.

1 files changed, 146 insertions, 0 deletions

diff --git a/src/mongo/s/request_types/migration_secondary_throttle_options.h b/src/mongo/s/request_types/migration_secondary_throttle_options.h
new file mode 100644
index 00000000000..d18f41a8dad
--- /dev/null
+++ b/src/mongo/s/request_types/migration_secondary_throttle_options.h
@@ -0,0 +1,146 @@
+/**
+ *    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 <boost/optional.hpp>
+
+#include "mongo/bson/bsonobj.h"
+
+namespace mongo {
+
+class BSONObjBuilder;
+template <typename T>
+class StatusWith;
+struct WriteConcernOptions;
+
+/**
+ * Returns the default write concern for migration cleanup on the donor shard and for cloning
+ * documents on the destination shard.
+ */
+class MigrationSecondaryThrottleOptions {
+public:
+    enum SecondaryThrottleOption {
+        // The secondary throttle option is not set explicitly. Use the default for the service.
+        kDefault,
+
+        // The secondary throttle option is explicitly disabled.
+        kOff,
+
+        // The secondary throttle option is explicitly enabled and there potentially might be a
+        // write concern specified. If no write concern was specified, use the default.
+        kOn
+    };
+
+    /**
+     * Constructs an object with the specified secondary throttle option and no custom write
+     * concern.
+     */
+    static MigrationSecondaryThrottleOptions create(SecondaryThrottleOption option);
+
+    /**
+     * Constructs an object with the secondary throttle enabled and with the specified write
+     * concern.
+     */
+    static MigrationSecondaryThrottleOptions createWithWriteConcern(
+        const WriteConcernOptions& writeConcern);
+
+    /**
+     * Extracts the write concern settings from a BSON with the following format:
+     *
+     * {
+     *     secondaryThrottle: <bool>,                           // optional
+     *     _secondaryThrottle: <bool>,                          // optional
+     *     writeConcern: <WriteConcern formatted as BSONObj>    // optional
+     * }
+     *
+     * Note: secondaryThrottle takes precedence over _secondaryThrottle. If either of the two are
+     * missing, the secondaryThrottle enabled status defaults to true.
+     *
+     * Returns OK if the parse was successful.
+     */
+    static StatusWith<MigrationSecondaryThrottleOptions> createFromCommand(const BSONObj& obj);
+
+    /**
+     * Extracts the secondary throttle settings from a balancer configuration document, which can
+     * have the following format:
+     *
+     * {
+     *     _secondaryThrottle: <bool> | <WriteConcern formatted as BSONObj> // optional
+     * }
+     *
+     * If secondary throttle is not specified, uses kDefault.
+     */
+    static StatusWith<MigrationSecondaryThrottleOptions> createFromBalancerConfig(
+        const BSONObj& obj);
+
+    /**
+     * Returns the selected secondary throttle option.
+     */
+    SecondaryThrottleOption getSecondaryThrottle() const {
+        return _secondaryThrottle;
+    }
+
+    /**
+     * Returns whether secondary throttle is enabled and write concern was requested.
+     */
+    bool isWriteConcernSpecified() const {
+        return _writeConcernBSON.is_initialized();
+    }
+
+    /**
+     * Returns the custom write concern, which was requested. Must only be called if
+     * isWriteConcernSpecified returns true.
+     */
+    WriteConcernOptions getWriteConcern() const;
+
+    /**
+     * Returns a BSON representation of the current secondary throttle settings.
+     */
+    void append(BSONObjBuilder* builder) const;
+    BSONObj toBSON() const;
+
+    /**
+     * Returns true if the options match exactly.
+     */
+    bool operator==(const MigrationSecondaryThrottleOptions& other) const;
+    bool operator!=(const MigrationSecondaryThrottleOptions& other) const;
+
+private:
+    MigrationSecondaryThrottleOptions(SecondaryThrottleOption secondaryThrottle,
+                                      boost::optional<BSONObj> writeConcernBSON);
+
+    // What is the state of the secondaryThrottle option (kDefault means that it has not been set)
+    SecondaryThrottleOption _secondaryThrottle;
+
+    // Owned BSON object with the contents of the writeConcern. If this object is set, then
+    // secodaryThrottle must be true.
+    boost::optional<BSONObj> _writeConcernBSON;
+};
+
+}  // namespace mongo