// wiredtiger_kv_engine.cpp

/**
 *    Copyright (C) 2014 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.
 */

#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kStorage

#include "mongo/db/storage/wiredtiger/wiredtiger_kv_engine.h"

#include <boost/filesystem.hpp>
#include <boost/filesystem/operations.hpp>

#include "mongo/db/concurrency/write_conflict_exception.h"
#include "mongo/db/index/index_descriptor.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_global_options.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_index.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_record_store.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_recovery_unit.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_session_cache.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_size_storer.h"
#include "mongo/db/storage/wiredtiger/wiredtiger_util.h"
#include "mongo/util/log.h"
#include "mongo/util/processinfo.h"
#include "mongo/util/scopeguard.h"

#if !defined(__has_feature)
#define __has_feature(x) 0
#endif

namespace mongo {

    using std::set;
    using std::string;

    namespace {
        int mdb_handle_error(WT_EVENT_HANDLER *handler, WT_SESSION *session,
                             int errorCode, const char *message) {
            try {
                error() << "WiredTiger (" << errorCode << ") " << message;
                fassert( 28558, errorCode != WT_PANIC );
            }
            catch (...) {
                std::terminate();
            }
            return 0;
        }

        int mdb_handle_message( WT_EVENT_HANDLER *handler, WT_SESSION *session,
                                const char *message) {
            try {
                log() << "WiredTiger " << message;
            }
            catch (...) {
                std::terminate();
            }
            return 0;
        }

        int mdb_handle_progress( WT_EVENT_HANDLER *handler, WT_SESSION *session,
                                 const char *operation, uint64_t progress) {
            try {
                log() << "WiredTiger progress " << operation << " " << progress;
            }
            catch (...) {
                std::terminate();
            }

            return 0;
        }

        int mdb_handle_close( WT_EVENT_HANDLER *handler, WT_SESSION *session,
                              WT_CURSOR *cursor) {
            return 0;
        }
    }

    WiredTigerKVEngine::WiredTigerKVEngine( const std::string& path,
                                            const std::string& extraOpenOptions,
                                            bool durable,
                                            bool repair )
        : _path( path ),
          _durable( durable ),
          _sizeStorerSyncTracker( 100000, 60 * 1000 ) {

        _eventHandler.handle_error = mdb_handle_error;
        _eventHandler.handle_message = mdb_handle_message;
        _eventHandler.handle_progress = mdb_handle_progress;
        _eventHandler.handle_close = mdb_handle_close;

        size_t cacheSizeGB = wiredTigerGlobalOptions.cacheSizeGB;
        if (cacheSizeGB == 0) {
            // Since the user didn't provide a cache size, choose a reasonable default value.
            ProcessInfo pi;
            unsigned long long memSizeMB  = pi.getMemSizeMB();
            if ( memSizeMB  > 0 ) {
                double cacheMB = memSizeMB / 2;
                cacheSizeGB = static_cast<size_t>( cacheMB / 1024 );
                if ( cacheSizeGB < 1 )
                    cacheSizeGB = 1;
            }
        }

        if ( _durable ) {
            boost::filesystem::path journalPath = path;
            journalPath /= "journal";
            if ( !boost::filesystem::exists( journalPath ) ) {
                try {
                    boost::filesystem::create_directory( journalPath );
                }
                catch( std::exception& e) {
                    log() << "error creating journal dir " << journalPath.string() << ' ' << e.what();
                    throw;
                }
            }
        }

        std::stringstream ss;
        ss << "create,";
        ss << "cache_size=" << cacheSizeGB << "G,";
        ss << "session_max=20000,";
        ss << "eviction=(threads_max=4),";
        ss << "statistics=(fast),";
        if ( _durable ) {
            ss << "log=(enabled=true,archive=true,path=journal,compressor=";
            ss << wiredTigerGlobalOptions.journalCompressor << "),";
        }
        ss << "checkpoint=(wait=" << wiredTigerGlobalOptions.checkpointDelaySecs;
        ss << ",log_size=2GB),";
        ss << "statistics_log=(wait=" << wiredTigerGlobalOptions.statisticsLogDelaySecs << "),";
        ss << extraOpenOptions;
        string config = ss.str();
        log() << "wiredtiger_open config: " << config;
        int ret = wiredtiger_open(path.c_str(), &_eventHandler, config.c_str(), &_conn);
        // Invalid argument (EINVAL) is usually caused by invalid configuration string.
        // We still fassert() but without a stack trace.
        if (ret == EINVAL) {
            fassertFailedNoTrace(28561);
        }
        else if (ret != 0) {
            Status s(wtRCToStatus(ret));
            msgassertedNoTrace(28595, s.reason());
        }

        _sessionCache.reset( new WiredTigerSessionCache( this ) );

        _sizeStorerUri = "table:sizeStorer";
        {
            WiredTigerSession session(_conn);
            if (repair && _hasUri(session.getSession(), _sizeStorerUri)) {
                log() << "Repairing size cache";
                fassertNoTrace(28577, _salvageIfNeeded(_sizeStorerUri.c_str()));
            }
            WiredTigerSizeStorer* ss = new WiredTigerSizeStorer();
            ss->loadFrom( &session, _sizeStorerUri );
            _sizeStorer.reset( ss );
        }
    }


    WiredTigerKVEngine::~WiredTigerKVEngine() {
        if (_conn) {
            cleanShutdown();
        }

        _sizeStorer.reset( NULL );

        _sessionCache.reset( NULL );
    }

    void WiredTigerKVEngine::cleanShutdown() {
        log() << "WiredTigerKVEngine shutting down";
        syncSizeInfo(true);
        if (_conn) {
            // this must be the last thing we do before _conn->close();
            _sessionCache->shuttingDown();

#if !__has_feature(address_sanitizer)
            const char* config = "leak_memory=true";
#else
            const char* config = NULL;
#endif
            invariantWTOK( _conn->close(_conn, config) );
            _conn = NULL;
        }
    }

    Status WiredTigerKVEngine::okToRename( OperationContext* opCtx,
                                           StringData fromNS,
                                           StringData toNS,
                                           StringData ident,
                                           const RecordStore* originalRecordStore ) const {
        _sizeStorer->store( _uri( ident ),
                            originalRecordStore->numRecords( opCtx ),
                            originalRecordStore->dataSize( opCtx ) );
        syncSizeInfo(true);
        return Status::OK();
    }

    int64_t WiredTigerKVEngine::getIdentSize( OperationContext* opCtx,
                                              StringData ident ) {
        WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx);
        return WiredTigerUtil::getIdentSize(session->getSession(), _uri(ident) );
    }

    Status WiredTigerKVEngine::repairIdent( OperationContext* opCtx,
                                            StringData ident ) {
        WiredTigerSession* session = WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx);
        session->closeAllCursors();
        string uri = _uri(ident);
        return _salvageIfNeeded(uri.c_str());
    }

    Status WiredTigerKVEngine::_salvageIfNeeded(const char* uri) {
        // Using a side session to avoid transactional issues
        WiredTigerSession sessionWrapper(_conn);
        WT_SESSION* session = sessionWrapper.getSession();

        int rc = (session->verify)(session, uri, NULL);
        if (rc == 0) {
            log() << "Verify succeeded on uri " << uri << ". Not salvaging.";
            return Status::OK();
        }

        if (rc == EBUSY) {
            // SERVER-16457: verify and salvage are occasionally failing with EBUSY. For now we
            // lie and return OK to avoid breaking tests. This block should go away when that ticket
            // is resolved.
            error() << "Verify on " << uri << " failed with EBUSY. Assuming no salvage is needed.";
            return Status::OK();
        }

        // TODO need to cleanup the sizeStorer cache after salvaging.
        log() << "Verify failed on uri " << uri << ". Running a salvage operation.";
        return wtRCToStatus(session->salvage(session, uri, NULL), "Salvage failed:");
    }

    int WiredTigerKVEngine::flushAllFiles( bool sync ) {
        LOG(1) << "WiredTigerKVEngine::flushAllFiles";
        syncSizeInfo(true);

        WiredTigerSession session(_conn);
        WT_SESSION* s = session.getSession();
        invariantWTOK( s->checkpoint(s, NULL ) );

        return 1;
    }

    void WiredTigerKVEngine::syncSizeInfo( bool sync ) const {
        if ( !_sizeStorer )
            return;

        try {
            WiredTigerSession session(_conn);
            WT_SESSION* s = session.getSession();
            invariantWTOK( s->begin_transaction( s, sync ? "sync=true" : NULL ) );
            _sizeStorer->storeInto( &session, _sizeStorerUri );
            invariantWTOK( s->commit_transaction( s, NULL ) );
        }
        catch (const WriteConflictException&) {
            // ignore, it means someone else is doing it
        }
    }

    RecoveryUnit* WiredTigerKVEngine::newRecoveryUnit() {
        return new WiredTigerRecoveryUnit( _sessionCache.get() );
    }

    void WiredTigerKVEngine::setRecordStoreExtraOptions( const std::string& options ) {
        _rsOptions = options;
    }

    void WiredTigerKVEngine::setSortedDataInterfaceExtraOptions( const std::string& options ) {
        _indexOptions = options;
    }

    Status WiredTigerKVEngine::createRecordStore( OperationContext* opCtx,
                                                  StringData ns,
                                                  StringData ident,
                                                  const CollectionOptions& options ) {
        _checkIdentPath( ident );
        WiredTigerSession session(_conn);

        StatusWith<std::string> result =
            WiredTigerRecordStore::generateCreateString(ns, options, _rsOptions);
        if (!result.isOK()) {
            return result.getStatus();
        }
        std::string config = result.getValue();

        string uri = _uri( ident );
        WT_SESSION* s = session.getSession();
        LOG(2) << "WiredTigerKVEngine::createRecordStore uri: " << uri << " config: " << config;
        return wtRCToStatus( s->create( s, uri.c_str(), config.c_str() ) );
    }

    RecordStore* WiredTigerKVEngine::getRecordStore( OperationContext* opCtx,
                                                     StringData ns,
                                                     StringData ident,
                                                     const CollectionOptions& options ) {

        if (options.capped) {
            return new WiredTigerRecordStore(opCtx, ns, _uri(ident), options.capped,
                                             options.cappedSize ? options.cappedSize : 4096,
                                             options.cappedMaxDocs ? options.cappedMaxDocs : -1,
                                             NULL,
                                             _sizeStorer.get() );
        }
        else {
            return new WiredTigerRecordStore(opCtx, ns, _uri(ident),
                                             false, -1, -1, NULL, _sizeStorer.get() );
        }
    }

    string WiredTigerKVEngine::_uri( StringData ident ) const {
        return string("table:") + ident.toString();
    }

    Status WiredTigerKVEngine::createSortedDataInterface( OperationContext* opCtx,
                                                          StringData ident,
                                                          const IndexDescriptor* desc ) {
        _checkIdentPath( ident );
        StatusWith<std::string> result =
            WiredTigerIndex::generateCreateString(_indexOptions, *desc);
        if (!result.isOK()) {
            return result.getStatus();
        }

        std::string config = result.getValue();

        LOG(2) << "WiredTigerKVEngine::createSortedDataInterface ident: " << ident
               << " config: " << config;
        return wtRCToStatus(WiredTigerIndex::Create(opCtx, _uri(ident), config));
    }

    SortedDataInterface* WiredTigerKVEngine::getSortedDataInterface( OperationContext* opCtx,
                                                                     StringData ident,
                                                                     const IndexDescriptor* desc ) {
        if ( desc->unique() )
            return new WiredTigerIndexUnique( opCtx, _uri( ident ), desc );
        return new WiredTigerIndexStandard( opCtx, _uri( ident ), desc );
    }

    Status WiredTigerKVEngine::dropIdent( OperationContext* opCtx,
                                          StringData ident ) {
        _drop( ident );
        return Status::OK();
    }

    bool WiredTigerKVEngine::_drop( StringData ident ) {
        string uri = _uri( ident );

        WiredTigerSession session(_conn);

        int ret = session.getSession()->drop( session.getSession(), uri.c_str(), "force" );
        LOG(1) << "WT drop of  " << uri << " res " << ret;

        if ( ret == 0 ) {
            // yay, it worked
            return true;
        }

        if ( ret == EBUSY ) {
            // this is expected, queue it up
            {
                boost::mutex::scoped_lock lk( _identToDropMutex );
                _identToDrop.insert( uri );
            }
            _sessionCache->closeAll();
            return false;
        }

        invariantWTOK( ret );
        return false;
    }

    bool WiredTigerKVEngine::haveDropsQueued() const {
        if ( _sizeStorerSyncTracker.intervalHasElapsed() ) {
            _sizeStorerSyncTracker.resetLastTime();
            syncSizeInfo(false);
        }
        boost::mutex::scoped_lock lk( _identToDropMutex );
        return !_identToDrop.empty();
    }

    void WiredTigerKVEngine::dropAllQueued() {
        set<string> mine;
        {
            boost::mutex::scoped_lock lk( _identToDropMutex );
            mine = _identToDrop;
        }

        set<string> deleted;

        {
            WiredTigerSession session(_conn);
            for ( set<string>::const_iterator it = mine.begin(); it != mine.end(); ++it ) {
                string uri = *it;
                int ret = session.getSession()->drop( session.getSession(), uri.c_str(), "force" );
                LOG(1) << "WT queued drop of  " << uri << " res " << ret;

                if ( ret == 0 ) {
                    deleted.insert( uri );
                    continue;
                }

                if ( ret == EBUSY ) {
                    // leave in qeuue
                    continue;
                }

                invariantWTOK( ret );
            }
        }

        {
            boost::mutex::scoped_lock lk( _identToDropMutex );
            for ( set<string>::const_iterator it = deleted.begin(); it != deleted.end(); ++it ) {
                _identToDrop.erase( *it );
            }
        }
    }

    bool WiredTigerKVEngine::supportsDocLocking() const {
        return true;
    }

    bool WiredTigerKVEngine::supportsDirectoryPerDB() const {
        return true;
    }

    bool WiredTigerKVEngine::hasIdent(OperationContext* opCtx, StringData ident) const {
        return _hasUri(WiredTigerRecoveryUnit::get(opCtx)->getSession(opCtx)->getSession(),
                       _uri(ident));
    }

    bool WiredTigerKVEngine::_hasUri(WT_SESSION* session, const std::string& uri) const {
        // can't use WiredTigerCursor since this is called from constructor.
        WT_CURSOR* c = NULL;
        int ret = session->open_cursor(session, "metadata:", NULL, NULL, &c);
        if (ret == ENOENT) return false;
        invariantWTOK(ret);
        ON_BLOCK_EXIT(c->close, c);

        c->set_key(c, uri.c_str());
        return c->search(c) == 0;
    }

    std::vector<std::string> WiredTigerKVEngine::getAllIdents( OperationContext* opCtx ) const {
        std::vector<std::string> all;
        WiredTigerCursor cursor( "metadata:", WiredTigerSession::kMetadataCursorId, false, opCtx );
        WT_CURSOR* c = cursor.get();
        if ( !c )
            return all;

        while ( c->next(c) == 0 ) {
            const char* raw;
            c->get_key(c, &raw );
            StringData key(raw);
            size_t idx = key.find( ':' );
            if ( idx == string::npos )
                continue;
            StringData type = key.substr( 0, idx );
            if ( type != "table" )
                continue;

            StringData ident = key.substr(idx+1);
            if ( ident == "sizeStorer" )
                continue;

            all.push_back( ident.toString() );
        }

        return all;
    }

    int WiredTigerKVEngine::reconfigure(const char* str) {
        return _conn->reconfigure(_conn, str);
    }

    void WiredTigerKVEngine::_checkIdentPath( StringData ident ) {
        size_t start = 0;
        size_t idx;
        while ( ( idx = ident.find( '/', start ) ) != string::npos ) {
            StringData dir = ident.substr( 0, idx );

            boost::filesystem::path subdir = _path;
            subdir /= dir.toString();
            if ( !boost::filesystem::exists( subdir ) ) {
                LOG(1) << "creating subdirectory: " << dir;
                try {
                    boost::filesystem::create_directory( subdir );
                }
                catch (const std::exception& e) {
                    error() << "error creating path " << subdir.string() << ' ' << e.what();
                    throw;
                }
            }

            start = idx + 1;
        }
    }
}