func (db *DB) compactionError() {
	var (
		err     error
		wlocked bool
	)
noerr:
	// No error.
	for {
		select {
		case err = <-db.compErrSetC:
			switch {
			case err == nil:
			case errors.IsCorrupted(err):
				goto hasperr
			default:
				goto haserr
			}
		case _, _ = <-db.closeC:
			return
		}
	}
haserr:
	// Transient error.
	for {
		select {
		case db.compErrC <- err:
		case err = <-db.compErrSetC:
			switch {
			case err == nil:
				goto noerr
			case errors.IsCorrupted(err):
				goto hasperr
			default:
			}
		case _, _ = <-db.closeC:
			return
		}
	}
hasperr:
	// Persistent error.
	for {
		select {
		case db.compErrC <- err:
		case db.compPerErrC <- err:
		case db.writeLockC <- struct{}{}:
			// Hold write lock, so that write won't pass-through.
			wlocked = true
		case _, _ = <-db.closeC:
			if wlocked {
				// We should release the lock or Close will hang.
				<-db.writeLockC
			}
			return
		}
	}
}

func (i *mergedIterator) iterErr(iter Iterator) bool {
	if err := iter.Error(); err != nil {
		if i.errf != nil {
			i.errf(err)
		}
		if i.strict || !errors.IsCorrupted(err) {
			i.err = err
			return true
		}
	}
	return false
}

func (i *indexedIterator) dataErr() bool {
	if err := i.data.Error(); err != nil {
		if i.errf != nil {
			i.errf(err)
		}
		if i.strict || !errors.IsCorrupted(err) {
			i.err = err
			return true
		}
	}
	return false
}

// A "better" version of leveldb's errors.IsCorrupted.
func leveldbIsCorrupted(err error) bool {
	switch {
	case err == nil:
		return false

	case errors.IsCorrupted(err):
		return true

	case strings.Contains(err.Error(), "corrupted"):
		return true
	}

	return false
}

// New creates a new *info as Info.
//
// dir is the directory where the leveldb that caches responses will be written.
// client must be an authenticated client to make requests to the Android Build API.
func New(dir string, client *http.Client) (Info, error) {
	db, err := leveldb.OpenFile(dir, nil)
	if err != nil && errors.IsCorrupted(err) {
		db, err = leveldb.RecoverFile(dir, nil)
	}
	if err != nil {
		return nil, fmt.Errorf("Failed to open leveldb at %s: %s", dir, err)
	}
	c, err := newAndroidCommits(client)
	if err != nil {
		return nil, fmt.Errorf("Failed to create commits: %s", err)
	}

	i := &info{db: db, commits: c}
	go i.poll()

	return i, nil
}

//.........这里部分代码省略.........
		},
	}

	// If the read or write rate should be limited, set up a rate limiter for it.
	// This will be used on connections created in the connect and listen routines.

	opts := cfg.Options()

	if !opts.SymlinksEnabled {
		symlinks.Supported = false
	}

	protocol.PingTimeout = time.Duration(opts.PingTimeoutS) * time.Second
	protocol.PingIdleTime = time.Duration(opts.PingIdleTimeS) * time.Second

	if opts.MaxSendKbps > 0 {
		writeRateLimit = ratelimit.NewBucketWithRate(float64(1000*opts.MaxSendKbps), int64(5*1000*opts.MaxSendKbps))
	}
	if opts.MaxRecvKbps > 0 {
		readRateLimit = ratelimit.NewBucketWithRate(float64(1000*opts.MaxRecvKbps), int64(5*1000*opts.MaxRecvKbps))
	}

	if (opts.MaxRecvKbps > 0 || opts.MaxSendKbps > 0) && !opts.LimitBandwidthInLan {
		lans, _ = osutil.GetLans()
		networks := make([]string, 0, len(lans))
		for _, lan := range lans {
			networks = append(networks, lan.String())
		}
		l.Infoln("Local networks:", strings.Join(networks, ", "))
	}

	dbFile := locations[locDatabase]
	ldb, err := leveldb.OpenFile(dbFile, dbOpts())
	if err != nil && errors.IsCorrupted(err) {
		ldb, err = leveldb.RecoverFile(dbFile, dbOpts())
	}
	if err != nil {
		l.Fatalln("Cannot open database:", err, "- Is another copy of Syncthing already running?")
	}

	// Remove database entries for folders that no longer exist in the config
	folders := cfg.Folders()
	for _, folder := range db.ListFolders(ldb) {
		if _, ok := folders[folder]; !ok {
			l.Infof("Cleaning data for dropped folder %q", folder)
			db.DropFolder(ldb, folder)
		}
	}

	m := model.NewModel(cfg, myID, myName, "syncthing", Version, ldb)
	cfg.Subscribe(m)

	if t := os.Getenv("STDEADLOCKTIMEOUT"); len(t) > 0 {
		it, err := strconv.Atoi(t)
		if err == nil {
			m.StartDeadlockDetector(time.Duration(it) * time.Second)
		}
	} else if !IsRelease || IsBeta {
		m.StartDeadlockDetector(20 * 60 * time.Second)
	}

	// Clear out old indexes for other devices. Otherwise we'll start up and
	// start needing a bunch of files which are nowhere to be found. This
	// needs to be changed when we correctly do persistent indexes.
	for _, folderCfg := range cfg.Folders() {
		m.AddFolder(folderCfg)

func main() {
	flag.Parse()

	if enableBufferPool {
		bpool = util.NewBufferPool(opt.DefaultBlockSize + 128)
	}

	log.Printf("Test DB stored at %q", dbPath)
	if httpProf != "" {
		log.Printf("HTTP pprof listening at %q", httpProf)
		runtime.SetBlockProfileRate(1)
		go func() {
			if err := http.ListenAndServe(httpProf, nil); err != nil {
				log.Fatalf("HTTPPROF: %v", err)
			}
		}()
	}

	runtime.GOMAXPROCS(runtime.NumCPU())

	os.RemoveAll(dbPath)
	stor, err := storage.OpenFile(dbPath, false)
	if err != nil {
		log.Fatal(err)
	}
	tstor := &testingStorage{stor}
	defer tstor.Close()

	fatalf := func(err error, format string, v ...interface{}) {
		atomic.StoreUint32(&fail, 1)
		atomic.StoreUint32(&done, 1)
		log.Printf("FATAL: "+format, v...)
		if err != nil && errors.IsCorrupted(err) {
			cerr := err.(*errors.ErrCorrupted)
			if !cerr.Fd.Zero() && cerr.Fd.Type == storage.TypeTable {
				log.Print("FATAL: corruption detected, scanning...")
				if !tstor.scanTable(storage.FileDesc{Type: storage.TypeTable, Num: cerr.Fd.Num}, false) {
					log.Printf("FATAL: unable to find corrupted key/value pair in table %v", cerr.Fd)
				}
			}
		}
		runtime.Goexit()
	}

	if openFilesCacheCapacity == 0 {
		openFilesCacheCapacity = -1
	}
	o := &opt.Options{
		OpenFilesCacheCapacity: openFilesCacheCapacity,
		DisableBufferPool:      !enableBufferPool,
		DisableBlockCache:      !enableBlockCache,
		ErrorIfExist:           true,
		Compression:            opt.NoCompression,
	}
	if enableCompression {
		o.Compression = opt.DefaultCompression
	}

	db, err := leveldb.Open(tstor, o)
	if err != nil {
		log.Fatal(err)
	}
	defer db.Close()

	var (
		mu              = &sync.Mutex{}
		gGetStat        = &latencyStats{}
		gIterStat       = &latencyStats{}
		gWriteStat      = &latencyStats{}
		gTrasactionStat = &latencyStats{}
		startTime       = time.Now()

		writeReq    = make(chan *leveldb.Batch)
		writeAck    = make(chan error)
		writeAckAck = make(chan struct{})
	)

	go func() {
		for b := range writeReq {

			var err error
			if mrand.Float64() < transactionProb {
				log.Print("> Write using transaction")
				gTrasactionStat.start()
				var tr *leveldb.Transaction
				if tr, err = db.OpenTransaction(); err == nil {
					if err = tr.Write(b, nil); err == nil {
						if err = tr.Commit(); err == nil {
							gTrasactionStat.record(b.Len())
						}
					} else {
						tr.Discard()
					}
				}
			} else {
				gWriteStat.start()
				if err = db.Write(b, nil); err == nil {
					gWriteStat.record(b.Len())
				}
			}
//.........这里部分代码省略.........

func (ts *testingStorage) scanTable(fd storage.FileDesc, checksum bool) (corrupted bool) {
	r, err := ts.Open(fd)
	if err != nil {
		log.Fatal(err)
	}
	defer r.Close()

	size, err := r.Seek(0, os.SEEK_END)
	if err != nil {
		log.Fatal(err)
	}

	o := &opt.Options{
		DisableLargeBatchTransaction: true,
		Strict: opt.NoStrict,
	}
	if checksum {
		o.Strict = opt.StrictBlockChecksum | opt.StrictReader
	}
	tr, err := table.NewReader(r, size, fd, nil, bpool, o)
	if err != nil {
		log.Fatal(err)
	}
	defer tr.Release()

	checkData := func(i int, t string, data []byte) bool {
		if len(data) == 0 {
			panic(fmt.Sprintf("[%v] nil data: i=%d t=%s", fd, i, t))
		}

		checksum0, checksum1 := dataChecksum(data)
		if checksum0 != checksum1 {
			atomic.StoreUint32(&fail, 1)
			atomic.StoreUint32(&done, 1)
			corrupted = true

			data0, data1 := dataSplit(data)
			data0c0, data0c1 := dataChecksum(data0)
			data1c0, data1c1 := dataChecksum(data1)
			log.Printf("FATAL: [%v] Corrupted data i=%d t=%s (%#x != %#x): %x(%v) vs %x(%v)",
				fd, i, t, checksum0, checksum1, data0, data0c0 == data0c1, data1, data1c0 == data1c1)
			return true
		}
		return false
	}

	iter := tr.NewIterator(nil, nil)
	defer iter.Release()
	for i := 0; iter.Next(); i++ {
		ukey, _, kt, kerr := parseIkey(iter.Key())
		if kerr != nil {
			atomic.StoreUint32(&fail, 1)
			atomic.StoreUint32(&done, 1)
			corrupted = true

			log.Printf("FATAL: [%v] Corrupted ikey i=%d: %v", fd, i, kerr)
			return
		}
		if checkData(i, "key", ukey) {
			return
		}
		if kt == ktVal && checkData(i, "value", iter.Value()) {
			return
		}
	}
	if err := iter.Error(); err != nil {
		if errors.IsCorrupted(err) {
			atomic.StoreUint32(&fail, 1)
			atomic.StoreUint32(&done, 1)
			corrupted = true

			log.Printf("FATAL: [%v] Corruption detected: %v", fd, err)
		} else {
			log.Fatal(err)
		}
	}

	return
}

// NewReader creates a new initialized table reader for the file.
// The fi, cache and bpool is optional and can be nil.
//
// The returned table reader instance is goroutine-safe.
func NewReader(f io.ReaderAt, size int64, fd storage.FileDesc, cache *cache.CacheGetter, bpool *util.BufferPool, o *opt.Options) (*Reader, error) {
	if f == nil {
		return nil, errors.New("leveldb/table: nil file")
	}

	r := &Reader{
		fd:             fd,
		reader:         f,
		cache:          cache,
		bpool:          bpool,
		o:              o,
		cmp:            o.GetComparer(),
		verifyChecksum: o.GetStrict(opt.StrictBlockChecksum),
	}

	if size < footerLen {
		r.err = r.newErrCorrupted(0, size, "table", "too small")
		return r, nil
	}

	footerPos := size - footerLen
	var footer [footerLen]byte
	if _, err := r.reader.ReadAt(footer[:], footerPos); err != nil && err != io.EOF {
		return nil, err
	}
	if string(footer[footerLen-len(magic):footerLen]) != magic {
		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad magic number")
		return r, nil
	}

	var n int
	// Decode the metaindex block handle.
	r.metaBH, n = decodeBlockHandle(footer[:])
	if n == 0 {
		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad metaindex block handle")
		return r, nil
	}

	// Decode the index block handle.
	r.indexBH, n = decodeBlockHandle(footer[n:])
	if n == 0 {
		r.err = r.newErrCorrupted(footerPos, footerLen, "table-footer", "bad index block handle")
		return r, nil
	}

	// Read metaindex block.
	metaBlock, err := r.readBlock(r.metaBH, true)
	if err != nil {
		if errors.IsCorrupted(err) {
			r.err = err
			return r, nil
		} else {
			return nil, err
		}
	}

	// Set data end.
	r.dataEnd = int64(r.metaBH.offset)

	// Read metaindex.
	metaIter := r.newBlockIter(metaBlock, nil, nil, true)
	for metaIter.Next() {
		key := string(metaIter.Key())
		if !strings.HasPrefix(key, "filter.") {
			continue
		}
		fn := key[7:]
		if f0 := o.GetFilter(); f0 != nil && f0.Name() == fn {
			r.filter = f0
		} else {
			for _, f0 := range o.GetAltFilters() {
				if f0.Name() == fn {
					r.filter = f0
					break
				}
			}
		}
		if r.filter != nil {
			filterBH, n := decodeBlockHandle(metaIter.Value())
			if n == 0 {
				continue
			}
			r.filterBH = filterBH
			// Update data end.
			r.dataEnd = int64(filterBH.offset)
			break
		}
	}
	metaIter.Release()
	metaBlock.Release()

	// Cache index and filter block locally, since we don't have global cache.
	if cache == nil {
		r.indexBlock, err = r.readBlock(r.indexBH, true)
		if err != nil {
			if errors.IsCorrupted(err) {
//.........这里部分代码省略.........

func (r *Reader) find(key []byte, filtered bool, ro *opt.ReadOptions, noValue bool) (rkey, value []byte, err error) {
	r.mu.RLock()
	defer r.mu.RUnlock()

	if r.err != nil {
		err = r.err
		return
	}

	indexBlock, rel, err := r.getIndexBlock(true)
	if err != nil {
		return
	}
	defer rel.Release()

	index := r.newBlockIter(indexBlock, nil, nil, true)
	defer index.Release()
	if !index.Seek(key) {
		err = index.Error()
		if err == nil {
			err = ErrNotFound
		}
		return
	}
	dataBH, n := decodeBlockHandle(index.Value())
	if n == 0 {
		r.err = r.newErrCorruptedBH(r.indexBH, "bad data block handle")
		return
	}
	if filtered && r.filter != nil {
		filterBlock, frel, ferr := r.getFilterBlock(true)
		if ferr == nil {
			if !filterBlock.contains(r.filter, dataBH.offset, key) {
				frel.Release()
				return nil, nil, ErrNotFound
			}
			frel.Release()
		} else if !errors.IsCorrupted(ferr) {
			err = ferr
			return
		}
	}
	data := r.getDataIter(dataBH, nil, r.verifyChecksum, !ro.GetDontFillCache())
	defer data.Release()
	if !data.Seek(key) {
		err = data.Error()
		if err == nil {
			err = ErrNotFound
		}
		return
	}
	// Don't use block buffer, no need to copy the buffer.
	rkey = data.Key()
	if !noValue {
		if r.bpool == nil {
			value = data.Value()
		} else {
			// Use block buffer, and since the buffer will be recycled, the buffer
			// need to be copied.
			value = append([]byte{}, data.Value()...)
		}
	}
	return
}

func main() {
	defer common.LogPanic()

	var err error
	// Setup flags.
	dbConf := buildbot.DBConfigFromFlags() // Global init to initialize glog and parse arguments.

	// Global init to initialize glog and parse arguments.
	common.InitWithMetrics("internal", graphiteServer)

	if !*local {
		*targetList = metadata.Must(metadata.ProjectGet("datahopper_internal_targets"))
	}
	targets := strings.Split(*targetList, " ")
	glog.Infof("Targets: %#v", targets)

	codenameDB, err = leveldb.OpenFile(*codenameDbDir, nil)
	if err != nil && errors.IsCorrupted(err) {
		codenameDB, err = leveldb.RecoverFile(*codenameDbDir, nil)
	}
	if err != nil {
		glog.Fatalf("Failed to open codename leveldb at %s: %s", *codenameDbDir, err)
	}
	// Initialize the buildbot database.
	if !*local {
		if err := dbConf.GetPasswordFromMetadata(); err != nil {
			glog.Fatal(err)
		}
	}
	if err := dbConf.InitDB(); err != nil {
		glog.Fatal(err)
	}

	var cookieSalt = "notverysecret"
	var clientID = "31977622648-1873k0c1e5edaka4adpv1ppvhr5id3qm.apps.googleusercontent.com"
	var clientSecret = "cw0IosPu4yjaG2KWmppj2guj"
	var redirectURL = fmt.Sprintf("http://localhost%s/oauth2callback/", *port)
	if !*local {
		cookieSalt = metadata.Must(metadata.ProjectGet(metadata.COOKIESALT))
		clientID = metadata.Must(metadata.ProjectGet(metadata.CLIENT_ID))
		clientSecret = metadata.Must(metadata.ProjectGet(metadata.CLIENT_SECRET))
		redirectURL = "https://internal.skia.org/oauth2callback/"
	}
	login.Init(clientID, clientSecret, redirectURL, cookieSalt, login.DEFAULT_SCOPE, login.DEFAULT_DOMAIN_WHITELIST, *local)

	// Ingest Android framework builds.
	go func() {
		glog.Infof("Starting.")
		repos := gitinfo.NewRepoMap(*workdir)

		// In this case we don't want a backoff transport since the Apiary backend
		// seems to fail a lot, so we basically want to fall back to polling if a
		// call fails.
		client, err := auth.NewClientWithTransport(*local, *oauthCacheFile, "", &http.Transport{Dial: util.DialTimeout}, androidbuildinternal.AndroidbuildInternalScope, storage.CloudPlatformScope)
		if err != nil {
			glog.Fatalf("Unable to create installed app oauth client:%s", err)
		}

		buildService, err := androidbuildinternal.New(client)
		if err != nil {
			glog.Fatalf("Failed to obtain Android build service: %v", err)
		}
		glog.Infof("Ready to start loop.")
		step(targets, buildService, repos)
		for _ = range time.Tick(*period) {
			step(targets, buildService, repos)
		}
	}()

	r := mux.NewRouter()
	r.HandleFunc("/", indexHandler)
	r.HandleFunc("/builders/{codename}/builds/{buildNumber}", redirectHandler)
	r.HandleFunc("/builders/{codename}", builderRedirectHandler)
	r.HandleFunc("/loginstatus/", login.StatusHandler)
	r.HandleFunc("/logout/", login.LogoutHandler)
	r.HandleFunc("/oauth2callback/", login.OAuth2CallbackHandler)
	http.Handle("/", util.LoggingGzipRequestResponse(r))
	glog.Fatal(http.ListenAndServe(*port, nil))
}

func recoverTable(s *session, o *opt.Options) error {
	o = dupOptions(o)
	// Mask StrictReader, lets StrictRecovery doing its job.
	o.Strict &= ^opt.StrictReader

	// Get all tables and sort it by file number.
	tableFiles_, err := s.getFiles(storage.TypeTable)
	if err != nil {
		return err
	}
	tableFiles := files(tableFiles_)
	tableFiles.sort()

	var (
		maxSeq                                                            uint64
		recoveredKey, goodKey, corruptedKey, corruptedBlock, droppedTable int

		// We will drop corrupted table.
		strict = o.GetStrict(opt.StrictRecovery)

		rec   = &sessionRecord{numLevel: o.GetNumLevel()}
		bpool = util.NewBufferPool(o.GetBlockSize() + 5)
	)
	buildTable := func(iter iterator.Iterator) (tmp storage.File, size int64, err error) {
		tmp = s.newTemp()
		writer, err := tmp.Create()
		if err != nil {
			return
		}
		defer func() {
			writer.Close()
			if err != nil {
				tmp.Remove()
				tmp = nil
			}
		}()

		// Copy entries.
		tw := table.NewWriter(writer, o)
		for iter.Next() {
			key := iter.Key()
			if validIkey(key) {
				err = tw.Append(key, iter.Value())
				if err != nil {
					return
				}
			}
		}
		err = iter.Error()
		if err != nil {
			return
		}
		err = tw.Close()
		if err != nil {
			return
		}
		err = writer.Sync()
		if err != nil {
			return
		}
		size = int64(tw.BytesLen())
		return
	}
	recoverTable := func(file storage.File) error {
		s.logf("[email protected] recovering @%d", file.Num())
		reader, err := file.Open()
		if err != nil {
			return err
		}
		var closed bool
		defer func() {
			if !closed {
				reader.Close()
			}
		}()

		// Get file size.
		size, err := reader.Seek(0, 2)
		if err != nil {
			return err
		}

		var (
			tSeq                                     uint64
			tgoodKey, tcorruptedKey, tcorruptedBlock int
			imin, imax                               []byte
		)
		tr, err := table.NewReader(reader, size, storage.NewFileInfo(file), nil, bpool, o)
		if err != nil {
			return err
		}
		iter := tr.NewIterator(nil, nil)
		iter.(iterator.ErrorCallbackSetter).SetErrorCallback(func(err error) {
			if errors.IsCorrupted(err) {
				s.logf("[email protected] block corruption @%d %q", file.Num(), err)
				tcorruptedBlock++
			}
		})

		// Scan the table.
//.........这里部分代码省略.........

func (db *DB) recoverJournalRO() error {
	// Get all journals and sort it by file number.
	rawFds, err := db.s.stor.List(storage.TypeJournal)
	if err != nil {
		return err
	}
	sortFds(rawFds)

	// Journals that will be recovered.
	var fds []storage.FileDesc
	for _, fd := range rawFds {
		if fd.Num >= db.s.stJournalNum || fd.Num == db.s.stPrevJournalNum {
			fds = append(fds, fd)
		}
	}

	var (
		// Options.
		strict      = db.s.o.GetStrict(opt.StrictJournal)
		checksum    = db.s.o.GetStrict(opt.StrictJournalChecksum)
		writeBuffer = db.s.o.GetWriteBuffer()

		mdb = memdb.New(db.s.icmp, writeBuffer)
	)

	// Recover journals.
	if len(fds) > 0 {
		db.logf("[email protected] RO·Mode F·%d", len(fds))

		var (
			jr    *journal.Reader
			buf   = &util.Buffer{}
			batch = &Batch{}
		)

		for _, fd := range fds {
			db.logf("[email protected] recovering @%d", fd.Num)

			fr, err := db.s.stor.Open(fd)
			if err != nil {
				return err
			}

			// Create or reset journal reader instance.
			if jr == nil {
				jr = journal.NewReader(fr, dropper{db.s, fd}, strict, checksum)
			} else {
				jr.Reset(fr, dropper{db.s, fd}, strict, checksum)
			}

			// Replay journal to memdb.
			for {
				r, err := jr.Next()
				if err != nil {
					if err == io.EOF {
						break
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}

				buf.Reset()
				if _, err := buf.ReadFrom(r); err != nil {
					if err == io.ErrUnexpectedEOF {
						// This is error returned due to corruption, with strict == false.
						continue
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}
				if err := batch.memDecodeAndReplay(db.seq, buf.Bytes(), mdb); err != nil {
					if !strict && errors.IsCorrupted(err) {
						db.s.logf("journal error: %v (skipped)", err)
						// We won't apply sequence number as it might be corrupted.
						continue
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}

				// Save sequence number.
				db.seq = batch.seq + uint64(batch.Len())
			}

			fr.Close()
		}
	}

	// Set memDB.
	db.mem = &memDB{db: db, DB: mdb, ref: 1}

	return nil
}

//.........这里部分代码省略.........
						return err
					}
				}

				rec.setJournalNum(fd.Num)
				rec.setSeqNum(db.seq)
				if err := db.s.commit(rec); err != nil {
					fr.Close()
					return err
				}
				rec.resetAddedTables()

				db.s.stor.Remove(ofd)
				ofd = storage.FileDesc{}
			}

			// Replay journal to memdb.
			mdb.Reset()
			for {
				r, err := jr.Next()
				if err != nil {
					if err == io.EOF {
						break
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}

				buf.Reset()
				if _, err := buf.ReadFrom(r); err != nil {
					if err == io.ErrUnexpectedEOF {
						// This is error returned due to corruption, with strict == false.
						continue
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}
				if err := batch.memDecodeAndReplay(db.seq, buf.Bytes(), mdb); err != nil {
					if !strict && errors.IsCorrupted(err) {
						db.s.logf("journal error: %v (skipped)", err)
						// We won't apply sequence number as it might be corrupted.
						continue
					}

					fr.Close()
					return errors.SetFd(err, fd)
				}

				// Save sequence number.
				db.seq = batch.seq + uint64(batch.Len())

				// Flush it if large enough.
				if mdb.Size() >= writeBuffer {
					if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
						fr.Close()
						return err
					}

					mdb.Reset()
				}
			}

			fr.Close()
			ofd = fd
		}

		// Flush the last memdb.
		if mdb.Len() > 0 {
			if _, err := db.s.flushMemdb(rec, mdb, 0); err != nil {
				return err
			}
		}
	}

	// Create a new journal.
	if _, err := db.newMem(0); err != nil {
		return err
	}

	// Commit.
	rec.setJournalNum(db.journalFd.Num)
	rec.setSeqNum(db.seq)
	if err := db.s.commit(rec); err != nil {
		// Close journal on error.
		if db.journal != nil {
			db.journal.Close()
			db.journalWriter.Close()
		}
		return err
	}

	// Remove the last obsolete journal file.
	if !ofd.Nil() {
		db.s.stor.Remove(ofd)
	}

	return nil
}

// Recover a database session; need external synchronization.
func (s *session) recover() (err error) {
	defer func() {
		if os.IsNotExist(err) {
			// Don't return os.ErrNotExist if the underlying storage contains
			// other files that belong to LevelDB. So the DB won't get trashed.
			if fds, _ := s.stor.List(storage.TypeAll); len(fds) > 0 {
				err = &errors.ErrCorrupted{Fd: storage.FileDesc{Type: storage.TypeManifest}, Err: &errors.ErrMissingFiles{}}
			}
		}
	}()

	fd, err := s.stor.GetMeta()
	if err != nil {
		return
	}

	reader, err := s.stor.Open(fd)
	if err != nil {
		return
	}
	defer reader.Close()

	var (
		// Options.
		strict = s.o.GetStrict(opt.StrictManifest)

		jr      = journal.NewReader(reader, dropper{s, fd}, strict, true)
		rec     = &sessionRecord{}
		staging = s.stVersion.newStaging()
	)
	for {
		var r io.Reader
		r, err = jr.Next()
		if err != nil {
			if err == io.EOF {
				err = nil
				break
			}
			return errors.SetFd(err, fd)
		}

		err = rec.decode(r)
		if err == nil {
			// save compact pointers
			for _, r := range rec.compPtrs {
				s.setCompPtr(r.level, internalKey(r.ikey))
			}
			// commit record to version staging
			staging.commit(rec)
		} else {
			err = errors.SetFd(err, fd)
			if strict || !errors.IsCorrupted(err) {
				return
			}
			s.logf("manifest error: %v (skipped)", errors.SetFd(err, fd))
		}
		rec.resetCompPtrs()
		rec.resetAddedTables()
		rec.resetDeletedTables()
	}

	switch {
	case !rec.has(recComparer):
		return newErrManifestCorrupted(fd, "comparer", "missing")
	case rec.comparer != s.icmp.uName():
		return newErrManifestCorrupted(fd, "comparer", fmt.Sprintf("mismatch: want '%s', got '%s'", s.icmp.uName(), rec.comparer))
	case !rec.has(recNextFileNum):
		return newErrManifestCorrupted(fd, "next-file-num", "missing")
	case !rec.has(recJournalNum):
		return newErrManifestCorrupted(fd, "journal-file-num", "missing")
	case !rec.has(recSeqNum):
		return newErrManifestCorrupted(fd, "seq-num", "missing")
	}

	s.manifestFd = fd
	s.setVersion(staging.finish())
	s.setNextFileNum(rec.nextFileNum)
	s.recordCommited(rec)
	return nil
}

func (db *DB) recoverJournal() error {
	// Get all tables and sort it by file number.
	journalFiles_, err := db.s.getFiles(storage.TypeJournal)
	if err != nil {
		return err
	}
	journalFiles := files(journalFiles_)
	journalFiles.sort()

	// Discard older journal.
	prev := -1
	for i, file := range journalFiles {
		if file.Num() >= db.s.stJournalNum {
			if prev >= 0 {
				i--
				journalFiles[i] = journalFiles[prev]
			}
			journalFiles = journalFiles[i:]
			break
		} else if file.Num() == db.s.stPrevJournalNum {
			prev = i
		}
	}

	var jr *journal.Reader
	var of storage.File
	var mem *memdb.DB
	batch := new(Batch)
	cm := newCMem(db.s)
	buf := new(util.Buffer)
	// Options.
	strict := db.s.o.GetStrict(opt.StrictJournal)
	checksum := db.s.o.GetStrict(opt.StrictJournalChecksum)
	writeBuffer := db.s.o.GetWriteBuffer()
	recoverJournal := func(file storage.File) error {
		db.logf("[email protected] recovering @%d", file.Num())
		reader, err := file.Open()
		if err != nil {
			return err
		}
		defer reader.Close()

		// Create/reset journal reader instance.
		if jr == nil {
			jr = journal.NewReader(reader, dropper{db.s, file}, strict, checksum)
		} else {
			jr.Reset(reader, dropper{db.s, file}, strict, checksum)
		}

		// Flush memdb and remove obsolete journal file.
		if of != nil {
			if mem.Len() > 0 {
				if err := cm.flush(mem, 0); err != nil {
					return err
				}
			}
			if err := cm.commit(file.Num(), db.seq); err != nil {
				return err
			}
			cm.reset()
			of.Remove()
			of = nil
		}

		// Replay journal to memdb.
		mem.Reset()
		for {
			r, err := jr.Next()
			if err != nil {
				if err == io.EOF {
					break
				}
				return errors.SetFile(err, file)
			}

			buf.Reset()
			if _, err := buf.ReadFrom(r); err != nil {
				if err == io.ErrUnexpectedEOF {
					// This is error returned due to corruption, with strict == false.
					continue
				} else {
					return errors.SetFile(err, file)
				}
			}
			if err := batch.memDecodeAndReplay(db.seq, buf.Bytes(), mem); err != nil {
				if strict || !errors.IsCorrupted(err) {
					return errors.SetFile(err, file)
				} else {
					db.s.logf("journal error: %v (skipped)", err)
					// We won't apply sequence number as it might be corrupted.
					continue
				}
			}

			// Save sequence number.
			db.seq = batch.seq + uint64(batch.Len())

			// Flush it if large enough.
			if mem.Size() >= writeBuffer {
				if err := cm.flush(mem, 0); err != nil {
//.........这里部分代码省略.........

func (db *DB) compactionTransact(name string, t compactionTransactInterface) {
	defer func() {
		if x := recover(); x != nil {
			if x == errCompactionTransactExiting {
				if err := t.revert(); err != nil {
					db.logf("%s revert error %q", name, err)
				}
			}
			panic(x)
		}
	}()

	const (
		backoffMin = 1 * time.Second
		backoffMax = 8 * time.Second
		backoffMul = 2 * time.Second
	)
	var (
		backoff  = backoffMin
		backoffT = time.NewTimer(backoff)
		lastCnt  = compactionTransactCounter(0)

		disableBackoff = db.s.o.GetDisableCompactionBackoff()
	)
	for n := 0; ; n++ {
		// Check wether the DB is closed.
		if db.isClosed() {
			db.logf("%s exiting", name)
			db.compactionExitTransact()
		} else if n > 0 {
			db.logf("%s retrying N·%d", name, n)
		}

		// Execute.
		cnt := compactionTransactCounter(0)
		err := t.run(&cnt)
		if err != nil {
			db.logf("%s error I·%d %q", name, cnt, err)
		}

		// Set compaction error status.
		select {
		case db.compErrSetC <- err:
		case perr := <-db.compPerErrC:
			if err != nil {
				db.logf("%s exiting (persistent error %q)", name, perr)
				db.compactionExitTransact()
			}
		case _, _ = <-db.closeC:
			db.logf("%s exiting", name)
			db.compactionExitTransact()
		}
		if err == nil {
			return
		}
		if errors.IsCorrupted(err) {
			db.logf("%s exiting (corruption detected)", name)
			db.compactionExitTransact()
		}

		if !disableBackoff {
			// Reset backoff duration if counter is advancing.
			if cnt > lastCnt {
				backoff = backoffMin
				lastCnt = cnt
			}

			// Backoff.
			backoffT.Reset(backoff)
			if backoff < backoffMax {
				backoff *= backoffMul
				if backoff > backoffMax {
					backoff = backoffMax
				}
			}
			select {
			case <-backoffT.C:
			case _, _ = <-db.closeC:
				db.logf("%s exiting", name)
				db.compactionExitTransact()
			}
		}
	}
}

func main() {
	defer common.LogPanic()

	var err error

	// Global init to initialize glog and parse arguments.
	common.InitWithMetrics("internal", graphiteServer)

	if !*local {
		*targetList = metadata.Must(metadata.ProjectGet("datahopper_internal_targets"))
	}
	targets := strings.Split(*targetList, " ")
	glog.Infof("Targets: %#v", targets)

	codenameDB, err = leveldb.OpenFile(*codenameDbDir, nil)
	if err != nil && errors.IsCorrupted(err) {
		codenameDB, err = leveldb.RecoverFile(*codenameDbDir, nil)
	}
	if err != nil {
		glog.Fatalf("Failed to open codename leveldb at %s: %s", *codenameDbDir, err)
	}
	// Initialize the buildbot database.
	db, err = buildbot.NewRemoteDB(*buildbotDbHost)
	if err != nil {
		glog.Fatal(err)
	}

	var redirectURL = fmt.Sprintf("http://localhost%s/oauth2callback/", *port)
	if !*local {
		redirectURL = "https://internal.skia.org/oauth2callback/"
	}
	if err := login.InitFromMetadataOrJSON(redirectURL, login.DEFAULT_SCOPE, login.DEFAULT_DOMAIN_WHITELIST); err != nil {
		glog.Fatalf("Failed to initialize login system: %s", err)

	}

	if *local {
		webhook.InitRequestSaltForTesting()
	} else {
		webhook.MustInitRequestSaltFromMetadata()
	}

	repos = gitinfo.NewRepoMap(*workdir)

	// Ingest Android framework builds.
	go func() {
		glog.Infof("Starting.")

		// In this case we don't want a backoff transport since the Apiary backend
		// seems to fail a lot, so we basically want to fall back to polling if a
		// call fails.
		client, err := auth.NewJWTServiceAccountClient("", "", &http.Transport{Dial: util.DialTimeout}, androidbuildinternal.AndroidbuildInternalScope, storage.CloudPlatformScope)
		if err != nil {
			glog.Fatalf("Unable to create authenticated client: %s", err)
		}

		buildService, err := androidbuildinternal.New(client)
		if err != nil {
			glog.Fatalf("Failed to obtain Android build service: %v", err)
		}
		glog.Infof("Ready to start loop.")
		step(targets, buildService)
		for _ = range time.Tick(*period) {
			step(targets, buildService)
		}
	}()

	r := mux.NewRouter()
	r.HandleFunc("/", indexHandler)
	r.HandleFunc("/builders/{codename}/builds/{buildNumber}", redirectHandler)
	r.HandleFunc("/builders/{codename}", builderRedirectHandler)
	r.HandleFunc("/ingestBuild", ingestBuildHandler)
	r.HandleFunc("/loginstatus/", login.StatusHandler)
	r.HandleFunc("/logout/", login.LogoutHandler)
	r.HandleFunc("/oauth2callback/", login.OAuth2CallbackHandler)
	http.Handle("/", util.LoggingGzipRequestResponse(r))
	glog.Fatal(http.ListenAndServe(*port, nil))
}