Revert "SERVER-23445 create LocalClient class for local queries/writes, implement a find query interface"

This reverts commit 02779909333ff4333c316b54b9fbb2fdd635e15a.

6 files changed, 17 insertions, 501 deletions

diff --git a/src/mongo/db/SConscript b/src/mongo/db/SConscript
index 2bd2e2403f0..deac8c6ec4c 100644
--- a/src/mongo/db/SConscript
+++ b/src/mongo/db/SConscript
@@ -114,30 +114,6 @@ env.CppUnitTest(
 env.CppUnitTest('record_id_test', 'record_id_test.cpp', LIBDEPS=[])
 
 env.Library(
-    target='local_client',
-    source=[
-        'local_client.cpp',
-    ],
-    LIBDEPS=[
-        'query/query',
-    ]
-)
-
-env.CppUnitTest(
-    target='local_client_test',
-    source=[
-        'local_client_test.cpp',
-    ],
-    LIBDEPS=[
-        'local_client',
-        'repl/replmocks',
-        'serveronly',
-        '$BUILD_DIR/mongo/util/ntservice_mock',
-    ],
-    NO_CRUTCH = True,
-)
-
-env.Library(
     target='startup_warnings_common',
     source=[
         'startup_warnings_common.cpp',
diff --git a/src/mongo/db/dbhelpers.cpp b/src/mongo/db/dbhelpers.cpp
index 3b572eacbab..fa7824f0768 100644
--- a/src/mongo/db/dbhelpers.cpp
+++ b/src/mongo/db/dbhelpers.cpp
@@ -107,6 +107,9 @@ void Helpers::ensureIndex(OperationContext* txn,
     wunit.commit();
 }
 
+/* fetch a single object from collection ns that matches query
+   set your db SavedContext first
+*/
 bool Helpers::findOne(OperationContext* txn,
                       Collection* collection,
                       const BSONObj& query,
@@ -119,6 +122,9 @@ bool Helpers::findOne(OperationContext* txn,
     return true;
 }
 
+/* fetch a single object from collection ns that matches query
+   set your db SavedContext first
+*/
 RecordId Helpers::findOne(OperationContext* txn,
                           Collection* collection,
                           const BSONObj& query,
diff --git a/src/mongo/db/dbhelpers.h b/src/mongo/db/dbhelpers.h
index 334857bd10a..53d0839711b 100644
--- a/src/mongo/db/dbhelpers.h
+++ b/src/mongo/db/dbhelpers.h
@@ -69,26 +69,23 @@ struct Helpers {
                             bool unique,
                             const char* name);
 
-    /**
-     * Fetches a single BSONObj document from the given collection that matches query.
-     *
-     * @param collection - collection to be queried.
-     * @param query - the query to perform. Note this is the low level portion of query so
-     *                "orderby : ..." won't work.
-     * @param result - holds the found BSONObj document, if found.
-     * @param requireIndex - if true, assert if no index for the query. A way to guard against
-     *                       writing a slow query.
-     * @return true if a document is found.
-     */
+    /* fetch a single object from collection ns that matches query.
+       set your db SavedContext first.
+
+       @param query - the query to perform.  note this is the low level portion of query so
+                      "orderby : ..." won't work.
+
+       @param requireIndex if true, assert if no index for the query.  a way to guard against
+       writing a slow query.
+
+       @return true if object found
+    */
     static bool findOne(OperationContext* txn,
                         Collection* collection,
                         const BSONObj& query,
                         BSONObj& result,
                         bool requireIndex = false);
 
-    /**
-     * Fetches the RecordId location of a single object from collection ns that matches query.
-     */
     static RecordId findOne(OperationContext* txn,
                             Collection* collection,
                             const BSONObj& query,
diff --git a/src/mongo/db/local_client.cpp b/src/mongo/db/local_client.cpp
deleted file mode 100644
index f9aded6e30b..00000000000
--- a/src/mongo/db/local_client.cpp
+++ /dev/null
@@ -1,145 +0,0 @@
-/**
- * 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.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/local_client.h"
-
-#include "mongo/db/db_raii.h"
-#include "mongo/db/exec/working_set_common.h"
-#include "mongo/db/matcher/extensions_callback_real.h"
-#include "mongo/db/query/get_executor.h"
-
-namespace mongo {
-
-LocalClient::LocalClient(OperationContext* txn) : _txn(txn) {}
-
-StatusWith<LocalClient::LocalCursor> LocalClient::query(const NamespaceString& nss,
-                                                        const BSONObj& query,
-                                                        const BSONObj& sort) {
-    LocalCursor localCursor(_txn, nss, query, sort);
-    Status initStatus = localCursor._init();
-    if (!initStatus.isOK()) {
-        return initStatus;
-    }
-    return std::move(localCursor);
-}
-
-LocalClient::LocalCursor::LocalCursor(OperationContext* txn,
-                                      const NamespaceString& nss,
-                                      const BSONObj& query,
-                                      const BSONObj& sort)
-    : _txn(txn), _nss(nss), _query(query), _sort(sort) {}
-
-#if defined(_MSC_VER) && _MSC_VER < 1900
-LocalClient::LocalCursor::LocalCursor(LocalCursor&& other)
-    : _txn(std::move(other._txn)),
-      _nss(std::move(other._nss)),
-      _query(std::move(other._query)),
-      _sort(std::move(other._sort)),
-      _exec(std::move(other._exec)) {}
-
-LocalClient::LocalCursor& LocalClient::LocalCursor::operator=(LocalCursor&& other) {
-    _txn = std::move(other._txn);
-    _nss = std::move(other._nss);
-    _query = std::move(other._query);
-    _sort = std::move(other._sort);
-    _exec = std::move(other._exec);
-    return *this;
-}
-#endif
-
-Status LocalClient::LocalCursor::_init() {
-    // This function does its own locking, so the lock should not be held.
-    invariant(!_txn->lockState()->isLocked());
-
-    if (!_nss.isValid()) {
-        return {ErrorCodes::InvalidNamespace,
-                str::stream() << "Invalid collection name: '" << _nss.ns()};
-    }
-
-    auto lpq = LiteParsedQuery::makeAsFindCmd(_nss,
-                                              _query,
-                                              BSONObj(),  // projection
-                                              _sort);
-    ExtensionsCallbackReal extensionsCallback(_txn, &_nss);
-
-    auto canonicalQuery = CanonicalQuery::canonicalize(lpq.release(), extensionsCallback);
-    if (!canonicalQuery.isOK()) {
-        return canonicalQuery.getStatus();
-    }
-
-    AutoGetCollection ctx(_txn, _nss, MODE_IS);
-    Collection* collection = ctx.getCollection();
-
-    auto statusWithPlanExecutor = getExecutor(
-        _txn, collection, std::move(canonicalQuery.getValue()), PlanExecutor::YIELD_AUTO);
-    if (!statusWithPlanExecutor.isOK()) {
-        return statusWithPlanExecutor.getStatus();
-    }
-    _exec = std::move(statusWithPlanExecutor.getValue());
-    _exec->saveState();
-
-    return Status::OK();
-}
-
-StatusWith<boost::optional<BSONObj>> LocalClient::LocalCursor::next() {
-    // If _exec is not set, an error occurred or the cursor was exhausted on the previous call.
-    invariant(_exec);
-    // This function does its own locking, so the lock should not be held.
-    invariant(!_txn->lockState()->isLocked());
-    AutoGetCollection ctx(_txn, _nss, MODE_IS);
-
-    if (!_exec->restoreState()) {
-        _exec.reset();
-        return {ErrorCodes::OperationFailed,
-                str::stream()
-                    << "PlanExecutor could not be restored in LocalClient::LocalCursor::next()"};
-    }
-
-    BSONObj doc;
-    PlanExecutor::ExecState state = _exec->getNext(&doc, NULL);
-
-    if (state == PlanExecutor::IS_EOF) {
-        _exec.reset();
-        return {boost::none};
-    }
-
-    if (state != PlanExecutor::ADVANCED) {
-        _exec.reset();
-        return {ErrorCodes::OperationFailed,
-                str::stream() << "PlanExecutor error: " << WorkingSetCommon::toStatusString(doc)};
-    }
-
-    doc = doc.getOwned();
-    _exec->saveState();
-
-    return {doc};
-}
-
-}  // namespace mongo
diff --git a/src/mongo/db/local_client.h b/src/mongo/db/local_client.h
deleted file mode 100644
index 3b385f9fcee..00000000000
--- a/src/mongo/db/local_client.h
+++ /dev/null
@@ -1,135 +0,0 @@
-/**
- * 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 "mongo/base/disallow_copying.h"
-#include "mongo/base/status_with.h"
-#include "mongo/bson/bsonobj.h"
-#include "mongo/db/namespace_string.h"
-
-namespace mongo {
-
-class OperationContext;
-class PlanExecutor;
-
-/**
- * LocalClient handles local -- not over the network -- queries and writes. It acquires all
- * necessary collection locks: these locks should not be held by the caller.
- *
- * LocalClient is associated with a particular OperationContext and should not be passed between
- * threads.
- */
-class LocalClient {
-    MONGO_DISALLOW_COPYING(LocalClient);
-
-public:
-    class LocalCursor;
-
-    LocalClient(OperationContext* txn);
-
-    /**
-     * Sets up a local find query. Returns a LocalCursor object from which to request the next
-     * document that matches "query" in order "sort" from collection "nss".
-     *
-     * The caller should not hold the collection lock: locking is handled internally.
-     */
-    StatusWith<LocalCursor> query(const NamespaceString& nss,
-                                  const BSONObj& query,
-                                  const BSONObj& sort);
-
-    /**
-     * LocalCursor sets up and executes a local find query.
-     *
-     * Collection locking is handled internally. Lock is released between next() calls.
-     *
-     * The caller need only request the next document after instantiating the LocalCursor and
-     * calling init().
-     */
-    class LocalCursor {
-    public:
-        friend class LocalClient;
-
-#if defined(_MSC_VER) && _MSC_VER < 1900
-        LocalCursor(LocalCursor&& other);
-        LocalCursor& operator=(LocalCursor&& other);
-#else
-        LocalCursor(LocalCursor&& other) = default;
-        LocalCursor& operator=(LocalCursor&& other) = default;
-#endif
-
-        /**
-         * Seeks the next document that matches the query. Returns an error Status or an optional
-         * BSONObj. If optional is empty, there are no more documents that match "_query";
-         * otherwise the next document is returned.
-         *
-         * ErrorCodes::OperationFailed is returned if the PlanExecutor encounters an unrecoverable
-         * error or something happens to the collection -- such as an index or the collection
-         * itself being dropped -- between calls or when the PlanExecutor yields.
-         *
-         * Locking is handled internally: expects the collection lock not to be held.
-         */
-        StatusWith<boost::optional<BSONObj>> next();
-
-    private:
-        /**
-         * Instantiates a LocalCursor that returns documents from collection "nss" matching "query"
-         * in the "sort" order.
-         */
-        LocalCursor(OperationContext* txn,
-                    const NamespaceString& nss,
-                    const BSONObj& query,
-                    const BSONObj& sort);
-
-        /**
-         * Attempts to set up the find query, returns a Status to indicate success or failure.
-         *
-         * Locking is handled internally: expects the collection lock not to be held.
-         */
-        Status _init();
-
-        OperationContext* _txn;
-
-        // The collection in which to search.
-        NamespaceString _nss;
-
-        // Contains the query that selects documents to return.
-        BSONObj _query;
-
-        // Contains the sort order information.
-        BSONObj _sort;
-
-        // Find query PlanExecutor from which to request the next document.
-        std::unique_ptr<PlanExecutor> _exec;
-    };
-
-private:
-    OperationContext* const _txn;
-};
-
-}  // namespace mongo
diff --git a/src/mongo/db/local_client_test.cpp b/src/mongo/db/local_client_test.cpp
deleted file mode 100644
index 3b77b81701b..00000000000
--- a/src/mongo/db/local_client_test.cpp
+++ /dev/null
@@ -1,183 +0,0 @@
-/**
- * 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.
- */
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/local_client.h"
-
-#include <boost/optional.hpp>
-
-#include "mongo/base/checked_cast.h"
-#include "mongo/db/client.h"
-#include "mongo/db/catalog/collection.h"
-#include "mongo/db/catalog/database_holder.h"
-#include "mongo/db/db_raii.h"
-#include "mongo/db/service_context.h"
-#include "mongo/db/service_context_d.h"
-#include "mongo/db/repl/replication_coordinator_global.h"
-#include "mongo/db/repl/replication_coordinator_mock.h"
-#include "mongo/unittest/temp_dir.h"
-#include "mongo/unittest/unittest.h"
-
-namespace mongo {
-namespace {
-
-using unittest::assertGet;
-
-class LocalClientTest : public unittest::Test {
-protected:
-    ServiceContext::UniqueOperationContext _txn;
-
-private:
-    void setUp() override;
-    void tearDown() override;
-};
-
-void LocalClientTest::setUp() {
-    ServiceContext* serviceContext = getGlobalServiceContext();
-    if (!serviceContext->getGlobalStorageEngine()) {
-        // When using the 'devnull' storage engine, it is fine for the temporary directory to
-        // go away after the global storage engine is initialized.
-        unittest::TempDir tempDir("local_client_test");
-        storageGlobalParams.dbpath = tempDir.path();
-        storageGlobalParams.dbpath = tempDir.path();
-        storageGlobalParams.engine = "ephemeralForTest";
-        storageGlobalParams.engineSetByUser = true;
-        checked_cast<ServiceContextMongoD*>(getGlobalServiceContext())->createLockFile();
-        serviceContext->initializeGlobalStorageEngine();
-    }
-    Client::initThreadIfNotAlready();
-    _txn = serviceContext->makeOperationContext(&cc());
-
-    const repl::ReplSettings replSettings = {};
-    repl::setGlobalReplicationCoordinator(new repl::ReplicationCoordinatorMock(replSettings));
-}
-
-void LocalClientTest::tearDown() {
-    {
-        Lock::GlobalWrite globalLock(_txn->lockState());
-        BSONObjBuilder unused;
-        invariant(dbHolder().closeAll(_txn.get(), unused, false));
-    }
-    _txn.reset();
-    repl::setGlobalReplicationCoordinator(nullptr);
-}
-
-/**
- * Sets up a collection "nss" and populates it with documents.
- */
-void setUpCollection(OperationContext* txn,
-                     const NamespaceString& nss,
-                     std::vector<BSONObj> documentVector) {
-    AutoGetOrCreateDb autoDb(txn, nss.db(), MODE_X);
-    WriteUnitOfWork wuow(txn);
-    auto coll = autoDb.getDb()->getCollection(nss.ns());
-    if (!coll) {
-        coll = autoDb.getDb()->createCollection(txn, nss.ns());
-    }
-    ASSERT(coll);
-    for (const BSONObj& doc : documentVector) {
-        ASSERT_OK(coll->insertDocument(txn, doc, false));
-    }
-    wuow.commit();
-}
-
-/**
- * Drops collection "nss".
- */
-void dropCollection(OperationContext* txn, const NamespaceString& nss) {
-    AutoGetOrCreateDb autoDb(txn, nss.db(), MODE_X);
-    ASSERT_EQUALS(Status::OK(), autoDb.getDb()->dropCollection(txn, nss.ns()));
-}
-
-// Successful ordered find query.
-TEST_F(LocalClientTest, FindQuerySuccessful) {
-    LocalClient localClient(_txn.get());
-    NamespaceString nss("test.foo");
-    BSONObj firstDocument = BSON("_id" << 1 << "v" << 2);
-    BSONObj secondDocument = BSON("_id" << 4 << "v" << 2);
-    std::vector<BSONObj> documentVector = {firstDocument, secondDocument};
-    setUpCollection(_txn.get(), nss, documentVector);
-
-    // Set up find query that matches documents in the collection.
-    StatusWith<LocalClient::LocalCursor> localCursor =
-        localClient.query(nss, BSON("v" << 2), BSON("_id" << 1));
-    ASSERT_OK(localCursor.getStatus());
-
-    // Retrieve the first document and check it.
-    boost::optional<BSONObj> document = assertGet(localCursor.getValue().next());
-    ASSERT_TRUE(document);
-    ASSERT_EQUALS(*document, firstDocument);
-
-    // Retrieve the second document and check it.
-    document = assertGet(localCursor.getValue().next());
-    ASSERT_TRUE(document);
-    ASSERT_EQUALS(*document, secondDocument);
-
-    // Check that the cursor is exhausted: no more documents to retrieve.
-    document = assertGet(localCursor.getValue().next());
-    ASSERT_FALSE(document);
-
-    dropCollection(_txn.get(), nss);
-}
-
-// No documents match the find query.
-TEST_F(LocalClientTest, FindQueryNoDocumentsFound) {
-    LocalClient localClient(_txn.get());
-    NamespaceString nss("test.foo");
-    std::vector<BSONObj> documentVector = {BSON("_id" << 1 << "v" << 2)};
-    setUpCollection(_txn.get(), nss, documentVector);
-
-    // Set up find query that does not match any documents in the collection.
-    StatusWith<LocalClient::LocalCursor> localCursor =
-        localClient.query(nss, BSON("v" << 4), BSON("_id" << 1));
-    ASSERT_OK(localCursor.getStatus());
-
-    // Request the next document and receive nothing, with no errors.
-    boost::optional<BSONObj> document = assertGet(localCursor.getValue().next());
-    ASSERT_FALSE(document);
-
-    dropCollection(_txn.get(), nss);
-}
-
-// Collection being queried does not exist.
-TEST_F(LocalClientTest, FindQueryInitNoCollection) {
-    LocalClient localClient(_txn.get());
-
-    // Set up find query on a non-existent collection.
-    StatusWith<LocalClient::LocalCursor> localCursor =
-        localClient.query(NamespaceString("test.bam"), BSON("v" << 4), BSON("_id" << 1));
-    ASSERT_OK(localCursor.getStatus());
-
-    // Request the next document and receive nothing, with no errors.
-    boost::optional<BSONObj> document = assertGet(localCursor.getValue().next());
-    ASSERT_FALSE(document);
-}
-
-}  // namespace
-}  // namespace mongo