SERVER-25050 Cleanup Strategy and Shard class

No functional changes, just cleanup the Strategy class and rename
runBatchWriteCommand to runBatchWriteCommandOnConfig to better indicate
its intent.

8 files changed, 92 insertions, 104 deletions

diff --git a/jstests/core/pseudocommand_db.js b/jstests/core/pseudocommand_db.js
index 3b7a82cd44d..bbe523f1a5b 100644
--- a/jstests/core/pseudocommand_db.js
+++ b/jstests/core/pseudocommand_db.js
@@ -5,5 +5,4 @@
         // test that we can run the 'inprog' pseudocommand on any database.
         assert.commandWorked(testDB.$cmd.sys.inprog.findOne());
     }
-
 })();
diff --git a/src/mongo/db/commands.h b/src/mongo/db/commands.h
index 252bb639a30..ef808084454 100644
--- a/src/mongo/db/commands.h
+++ b/src/mongo/db/commands.h
@@ -329,7 +329,6 @@ public:
     // of Client. This will happen as part of SERVER-18292
     static void execCommandClientBasic(OperationContext* txn,
                                        Command* c,
-                                       Client& client,
                                        int queryOptions,
                                        const char* ns,
                                        BSONObj& cmdObj,
diff --git a/src/mongo/s/catalog/replset/sharding_catalog_client_impl.cpp b/src/mongo/s/catalog/replset/sharding_catalog_client_impl.cpp
index 59649d30e47..c59178d6d22 100644
--- a/src/mongo/s/catalog/replset/sharding_catalog_client_impl.cpp
+++ b/src/mongo/s/catalog/replset/sharding_catalog_client_impl.cpp
@@ -1316,8 +1316,8 @@ void ShardingCatalogClientImpl::writeConfigServerDirect(OperationContext* txn,
     }
 
     auto configShard = Grid::get(txn)->shardRegistry()->getConfigShard();
-    *batchResponse =
-        configShard->runBatchWriteCommand(txn, batchRequest, Shard::RetryPolicy::kNotIdempotent);
+    *batchResponse = configShard->runBatchWriteCommandOnConfig(
+        txn, batchRequest, Shard::RetryPolicy::kNotIdempotent);
 }
 
 Status ShardingCatalogClientImpl::insertConfigDocument(OperationContext* txn,
@@ -1340,7 +1340,7 @@ Status ShardingCatalogClientImpl::insertConfigDocument(OperationContext* txn,
     auto configShard = Grid::get(txn)->shardRegistry()->getConfigShard();
     for (int retry = 1; retry <= kMaxWriteRetry; retry++) {
         auto response =
-            configShard->runBatchWriteCommand(txn, request, Shard::RetryPolicy::kNoRetry);
+            configShard->runBatchWriteCommandOnConfig(txn, request, Shard::RetryPolicy::kNoRetry);
 
         Status status = response.toStatus();
 
@@ -1422,7 +1422,7 @@ StatusWith<bool> ShardingCatalogClientImpl::updateConfigDocument(
 
     auto configShard = Grid::get(txn)->shardRegistry()->getConfigShard();
     auto response =
-        configShard->runBatchWriteCommand(txn, request, Shard::RetryPolicy::kIdempotent);
+        configShard->runBatchWriteCommandOnConfig(txn, request, Shard::RetryPolicy::kIdempotent);
 
     Status status = response.toStatus();
     if (!status.isOK()) {
@@ -1454,7 +1454,7 @@ Status ShardingCatalogClientImpl::removeConfigDocuments(OperationContext* txn,
 
     auto configShard = Grid::get(txn)->shardRegistry()->getConfigShard();
     auto response =
-        configShard->runBatchWriteCommand(txn, request, Shard::RetryPolicy::kIdempotent);
+        configShard->runBatchWriteCommandOnConfig(txn, request, Shard::RetryPolicy::kIdempotent);
 
     return response.toStatus();
 }
diff --git a/src/mongo/s/client/shard.cpp b/src/mongo/s/client/shard.cpp
index 2855aa26842..68721257b5b 100644
--- a/src/mongo/s/client/shard.cpp
+++ b/src/mongo/s/client/shard.cpp
@@ -120,9 +120,10 @@ StatusWith<Shard::CommandResponse> Shard::runCommand(OperationContext* txn,
     MONGO_UNREACHABLE;
 }
 
-BatchedCommandResponse Shard::runBatchWriteCommand(OperationContext* txn,
-                                                   const BatchedCommandRequest& batchRequest,
-                                                   RetryPolicy retryPolicy) {
+BatchedCommandResponse Shard::runBatchWriteCommandOnConfig(
+    OperationContext* txn, const BatchedCommandRequest& batchRequest, RetryPolicy retryPolicy) {
+    invariant(isConfig());
+
     const std::string dbname = batchRequest.getNS().db().toString();
     invariant(batchRequest.sizeWriteOps() == 1);
 
diff --git a/src/mongo/s/client/shard.h b/src/mongo/s/client/shard.h
index af4eb97fcd0..191935611e2 100644
--- a/src/mongo/s/client/shard.h
+++ b/src/mongo/s/client/shard.h
@@ -148,12 +148,12 @@ public:
                                            RetryPolicy retryPolicy);
 
     /**
-     * Executes the specified batch write command on this shard's primary and retries on the
-     * specified set of errors using the specified retry policy.
+     * Expects a single-entry batch wrtie command and runs it on the config server's primary using
+     * the specified retry policy.
      */
-    BatchedCommandResponse runBatchWriteCommand(OperationContext* txn,
-                                                const BatchedCommandRequest& batchRequest,
-                                                RetryPolicy retryPolicy);
+    BatchedCommandResponse runBatchWriteCommandOnConfig(OperationContext* txn,
+                                                        const BatchedCommandRequest& batchRequest,
+                                                        RetryPolicy retryPolicy);
 
     /**
     * Warning: This method exhausts the cursor and pulls all data into memory.
diff --git a/src/mongo/s/commands/strategy.cpp b/src/mongo/s/commands/strategy.cpp
index d121c36346d..06040d20f60 100644
--- a/src/mongo/s/commands/strategy.cpp
+++ b/src/mongo/s/commands/strategy.cpp
@@ -108,7 +108,45 @@ void runAgainstRegistered(OperationContext* txn,
         return;
     }
 
-    Command::execCommandClientBasic(txn, c, cc(), queryOptions, ns, jsobj, anObjBuilder);
+    Command::execCommandClientBasic(txn, c, queryOptions, ns, jsobj, anObjBuilder);
+}
+
+/**
+ * This code handles the $cmd.sys.inprog queries.
+ */
+bool handleSpecialNamespaces(OperationContext* txn, Request& request, const QueryMessage& q) {
+    const char* ns = strstr(request.getns(), ".$cmd.sys.");
+    if (!ns)
+        return false;
+
+    ns += 10;
+
+    BSONObjBuilder reply;
+
+    const auto upgradeToRealCommand = [txn, &q, &reply](StringData commandName) {
+        BSONObjBuilder cmdBob;
+        cmdBob.append(commandName, 1);
+        cmdBob.appendElements(q.query);  // fields are validated by Commands
+        auto interposedCmd = cmdBob.done();
+
+        // Rewrite upgraded pseudoCommands to run on the 'admin' database.
+        const NamespaceString interposedNss("admin", "$cmd");
+        runAgainstRegistered(txn, interposedNss.ns().c_str(), interposedCmd, reply, q.queryOptions);
+    };
+
+    if (strcmp(ns, "inprog") == 0) {
+        upgradeToRealCommand("currentOp");
+    } else if (strcmp(ns, "killop") == 0) {
+        upgradeToRealCommand("killOp");
+    } else if (strcmp(ns, "unlock") == 0) {
+        reply.append("err", "can't do unlock through mongos");
+    } else {
+        warning() << "unknown sys command [" << ns << "]";
+        return false;
+    }
+
+    replyToQuery(0, request.session(), request.m(), reply.done());
+    return true;
 }
 
 }  // namespace
@@ -224,7 +262,7 @@ void Strategy::queryOp(OperationContext* txn, Request& request) {
 }
 
 void Strategy::clientCommandOp(OperationContext* txn, Request& request) {
-    QueryMessage q(request.d());
+    const QueryMessage q(request.d());
 
     LOG(3) << "command: " << q.ns << " " << redact(q.query) << " ntoreturn: " << q.ntoreturn
            << " options: " << q.queryOptions;
@@ -235,44 +273,40 @@ void Strategy::clientCommandOp(OperationContext* txn, Request& request) {
                       " " + q.query.toString());
     }
 
-    NamespaceString nss(request.getns());
-    // Regular queries are handled in strategy_shard.cpp
-    verify(nss.isCommand() || nss.isSpecialCommand());
+    const NamespaceString nss(request.getns());
+    invariant(nss.isCommand() || nss.isSpecialCommand());
 
     if (handleSpecialNamespaces(txn, request, q))
         return;
 
+    BSONObj cmdObj = q.query;
+
+    {
+        BSONElement e = cmdObj.firstElement();
+        if (e.type() == Object && (e.fieldName()[0] == '$' ? str::equals("query", e.fieldName() + 1)
+                                                           : str::equals("query", e.fieldName()))) {
+            // Extract the embedded query object.
+            if (cmdObj.hasField(Query::ReadPrefField.name())) {
+                // The command has a read preference setting. We don't want to lose this information
+                // so we copy this to a new field called $queryOptions.$readPreference
+                BSONObjBuilder finalCmdObjBuilder;
+                finalCmdObjBuilder.appendElements(e.embeddedObject());
+
+                BSONObjBuilder queryOptionsBuilder(finalCmdObjBuilder.subobjStart("$queryOptions"));
+                queryOptionsBuilder.append(cmdObj[Query::ReadPrefField.name()]);
+                queryOptionsBuilder.done();
+
+                cmdObj = finalCmdObjBuilder.obj();
+            } else {
+                cmdObj = e.embeddedObject();
+            }
+        }
+    }
+
     int loops = 5;
 
     while (true) {
         try {
-            BSONObj cmdObj = q.query;
-            {
-                BSONElement e = cmdObj.firstElement();
-                if (e.type() == Object &&
-                    (e.fieldName()[0] == '$' ? str::equals("query", e.fieldName() + 1)
-                                             : str::equals("query", e.fieldName()))) {
-                    // Extract the embedded query object.
-
-                    if (cmdObj.hasField(Query::ReadPrefField.name())) {
-                        // The command has a read preference setting. We don't want
-                        // to lose this information so we copy this to a new field
-                        // called $queryOptions.$readPreference
-                        BSONObjBuilder finalCmdObjBuilder;
-                        finalCmdObjBuilder.appendElements(e.embeddedObject());
-
-                        BSONObjBuilder queryOptionsBuilder(
-                            finalCmdObjBuilder.subobjStart("$queryOptions"));
-                        queryOptionsBuilder.append(cmdObj[Query::ReadPrefField.name()]);
-                        queryOptionsBuilder.done();
-
-                        cmdObj = finalCmdObjBuilder.obj();
-                    } else {
-                        cmdObj = e.embeddedObject();
-                    }
-                }
-            }
-
             OpQueryReplyBuilder reply;
             {
                 BSONObjBuilder builder(reply.bufBuilderForResults());
@@ -307,41 +341,6 @@ void Strategy::clientCommandOp(OperationContext* txn, Request& request) {
     }
 }
 
-// TODO: remove after MongoDB 3.2
-bool Strategy::handleSpecialNamespaces(OperationContext* txn, Request& request, QueryMessage& q) {
-    const char* ns = strstr(request.getns(), ".$cmd.sys.");
-    if (!ns)
-        return false;
-    ns += 10;
-
-    BSONObjBuilder reply;
-
-    const auto upgradeToRealCommand = [txn, &q, &reply](StringData commandName) {
-        BSONObjBuilder cmdBob;
-        cmdBob.append(commandName, 1);
-        cmdBob.appendElements(q.query);  // fields are validated by Commands
-        auto interposedCmd = cmdBob.done();
-        // Rewrite upgraded pseudoCommands to run on the 'admin' database.
-        NamespaceString interposedNss("admin", "$cmd");
-        runAgainstRegistered(txn, interposedNss.ns().c_str(), interposedCmd, reply, q.queryOptions);
-    };
-
-    if (strcmp(ns, "inprog") == 0) {
-        upgradeToRealCommand("currentOp");
-    } else if (strcmp(ns, "killop") == 0) {
-        upgradeToRealCommand("killOp");
-    } else if (strcmp(ns, "unlock") == 0) {
-        reply.append("err", "can't do unlock through mongos");
-    } else {
-        warning() << "unknown sys command [" << ns << "]";
-        return false;
-    }
-
-    BSONObj x = reply.done();
-    replyToQuery(0, request.session(), request.m(), x);
-    return true;
-}
-
 void Strategy::commandOp(OperationContext* txn,
                          const string& db,
                          const BSONObj& command,
diff --git a/src/mongo/s/commands/strategy.h b/src/mongo/s/commands/strategy.h
index f45031e2e0f..91031dee935 100644
--- a/src/mongo/s/commands/strategy.h
+++ b/src/mongo/s/commands/strategy.h
@@ -102,9 +102,6 @@ public:
      * DEPRECATED: should not be used by new code.
      */
     static void clientCommandOp(OperationContext* txn, Request& request);
-
-protected:
-    static bool handleSpecialNamespaces(OperationContext* txn, Request& request, QueryMessage& q);
 };
 
 }  // namespace mongo
diff --git a/src/mongo/s/s_only.cpp b/src/mongo/s/s_only.cpp
index 56d4238f3bc..d29eb7de7a4 100644
--- a/src/mongo/s/s_only.cpp
+++ b/src/mongo/s/s_only.cpp
@@ -1,6 +1,5 @@
-// s_only.cpp
-
-/*    Copyright 2009 10gen Inc.
+/**
+ *    Copyright (C) 2009-2016 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,
@@ -18,13 +17,13 @@
  *    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.
+ *    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.
  */
 
 #define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kSharding
@@ -83,20 +82,14 @@ void Command::execCommand(OperationContext* txn,
     std::string db = request.getDatabase().rawData();
     BSONObjBuilder result;
 
-    execCommandClientBasic(txn,
-                           command,
-                           *txn->getClient(),
-                           queryFlags,
-                           request.getDatabase().rawData(),
-                           cmdObj,
-                           result);
+    execCommandClientBasic(
+        txn, command, queryFlags, request.getDatabase().rawData(), cmdObj, result);
 
     replyBuilder->setCommandReply(result.done()).setMetadata(rpc::makeEmptyMetadata());
 }
 
 void Command::execCommandClientBasic(OperationContext* txn,
                                      Command* c,
-                                     Client& client,
                                      int queryOptions,
                                      const char* ns,
                                      BSONObj& cmdObj,
@@ -112,7 +105,7 @@ void Command::execCommandClientBasic(OperationContext* txn,
         return;
     }
 
-    Status status = _checkAuthorization(c, &client, dbname, cmdObj);
+    Status status = _checkAuthorization(c, txn->getClient(), dbname, cmdObj);
     if (!status.isOK()) {
         appendCommandStatus(result, status);
         return;