From 7dc9a83e8be3446551297e746dad4f6d74b7dca2 Mon Sep 17 00:00:00 2001
From: Andy Schwerin <schwerin@mongodb.com>
Date: Mon, 6 Apr 2015 14:40:56 -0400
Subject: SERVER-17817 Split ClusterLastErrorInfo concept out of ClientInfo
 type and into its own header.

With this change, ClientInfo is an empty subclass of ClientBasic, and in mongos we decorate
ClientBasic objects with information needed to do sharded last-error operations.
---
 src/mongo/s/cluster_last_error_info.h | 117 ++++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 src/mongo/s/cluster_last_error_info.h

(limited to 'src/mongo/s/cluster_last_error_info.h')

diff --git a/src/mongo/s/cluster_last_error_info.h b/src/mongo/s/cluster_last_error_info.h
new file mode 100644
index 00000000000..e1a912bfee2
--- /dev/null
+++ b/src/mongo/s/cluster_last_error_info.h
@@ -0,0 +1,117 @@
+/*
+ *    Copyright (C) 2010 10gen 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 <set>
+
+#include "mongo/db/client_basic.h"
+#include "mongo/s/chunk.h"
+#include "mongo/s/write_ops/batch_write_exec.h"
+
+namespace mongo {
+
+    /**
+     * Client decoration that holds information needed to by mongos to process
+     * getLastError commands.
+     */
+    class ClusterLastErrorInfo {
+    public:
+        static const ClientBasic::Decoration<ClusterLastErrorInfo> get;
+
+        /** new request not associated (yet or ever) with a client */
+        void newRequest();
+
+        /**
+         * notes that this client use this shard
+         * keeps track of all shards accessed this request
+         */
+        void addShardHost( const std::string& shardHost );
+
+        /**
+         * Notes that this client wrote to these particular hosts with write commands.
+         */
+        void addHostOpTime(ConnectionString connstr, HostOpTime stat);
+        void addHostOpTimes( const HostOpTimeMap& hostOpTimes );
+
+        /**
+         * gets shards used on the previous request
+         */
+        std::set<std::string>* getPrevShardHosts() const { return &_prev->shardHostsWritten; }
+
+        /**
+         * Gets the shards, hosts, and opTimes the client last wrote to with write commands.
+         */
+        const HostOpTimeMap& getPrevHostOpTimes() const {
+            return _prev->hostOpTimes;
+        }
+
+        /**
+         * resets the information stored for the current request
+         */
+        void clearRequestInfo(){ _cur->clear(); }
+
+        void disableForCommand();
+
+        /** @return if its ok to auto split from this client */
+        bool autoSplitOk() const { return _autoSplitOk && Chunk::ShouldAutoSplit; }
+
+        void noAutoSplit() { _autoSplitOk = false; }
+
+    private:
+        struct RequestInfo {
+
+            void clear() {
+                shardHostsWritten.clear();
+                hostOpTimes.clear();
+            }
+
+            std::set<std::string> shardHostsWritten;
+            HostOpTimeMap hostOpTimes;
+        };
+
+        // We use 2 so we can flip for getLastError type operations.
+        RequestInfo _infos[2];
+        RequestInfo* _cur = &_infos[0];
+        RequestInfo* _prev = &_infos[1];
+
+        bool _autoSplitOk = true;
+
+    };
+
+    /**
+     * Looks for $gleStats in a command response, and fills in ClientInfo with the data,
+     * if found.
+     * This data will be used by subsequent GLE calls, to ensure we look for the correct
+     * write on the correct PRIMARY.
+     * result: the result from calling runCommand
+     * conn: the std::string name of the hostAndPort where the command ran. This can be a replica
+     *       set seed list.
+     */
+    void saveGLEStats(const BSONObj& result, const std::string& conn);
+
+}  // namespace mongo
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