func Load(ts graph.TripleStore, cfg *config.Config, dec quad.Unmarshaler) error {
	bulker, canBulk := ts.(graph.BulkLoader)
	if canBulk {
		switch err := bulker.BulkLoad(dec); err {
		case nil:
			return nil
		case graph.ErrCannotBulkLoad:
			// Try individual loading.
		default:
			return err
		}
	}

	block := make([]quad.Quad, 0, cfg.LoadSize)
	for {
		t, err := dec.Unmarshal()
		if err != nil {
			if err == io.EOF {
				break
			}
			return err
		}
		block = append(block, t)
		if len(block) == cap(block) {
			ts.AddTripleSet(block)
			block = block[:0]
		}
	}
	ts.AddTripleSet(block)

	return nil
}

func checkIteratorContains(ts graph.TripleStore, it graph.Iterator, expected []string, t *testing.T) {
	var actual []string
	actual = nil
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		actual = append(actual, ts.GetNameFor(val))
	}
	actualSet := actual[:]
	for _, a := range expected {
		found := false
		for j, b := range actualSet {
			if a == b {
				actualSet = append(actualSet[:j], actualSet[j+1:]...)
				found = true
				break
			}
		}
		if !found {
			t.Error("Couldn't find", a, "in actual output.\nActual:", actual, "\nExpected: ", expected, "\nRemainder: ", actualSet)
			return
		}
	}
	if len(actualSet) != 0 {
		t.Error("Actual output has more than expected.\nActual:", actual, "\nExpected: ", expected, "\nRemainder: ", actualSet)
	}
}

func NewSingleReplication(ts graph.TripleStore, opts graph.Options) (graph.QuadWriter, error) {
	horizon := ts.Horizon()
	rep := &Single{nextID: horizon + 1, ts: ts}
	if horizon <= 0 {
		rep.nextID = 1
	}
	return rep, nil
}

func iteratedNames(qs graph.TripleStore, it graph.Iterator) []string {
	var res []string
	for graph.Next(it) {
		res = append(res, qs.NameOf(it.Result()))
	}
	sort.Strings(res)
	return res
}

func iteratedTriples(qs graph.TripleStore, it graph.Iterator) []quad.Quad {
	var res ordered
	for graph.Next(it) {
		res = append(res, qs.Quad(it.Result()))
	}
	sort.Sort(res)
	return res
}

func extractTripleFromIterator(ts graph.TripleStore, it graph.Iterator) []string {
	var output []string
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		output = append(output, ts.GetTriple(val).ToString())
	}
	return output
}

func extractValuesFromIterator(ts graph.TripleStore, it graph.Iterator) []string {
	var output []string
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		output = append(output, ts.GetNameFor(val))
	}
	return output
}

func iteratedNames(qs graph.TripleStore, it graph.Iterator) []string {
	var res []string
	for {
		val, ok := graph.Next(it)
		if !ok {
			break
		}
		res = append(res, qs.NameOf(val))
	}
	sort.Strings(res)
	return res
}

func iteratedTriples(qs graph.TripleStore, it graph.Iterator) []*quad.Quad {
	var res ordered
	for {
		val, ok := graph.Next(it)
		if !ok {
			break
		}
		res = append(res, qs.Quad(val))
	}
	sort.Sort(res)
	return res
}

func iteratedTriples(ts graph.TripleStore, it graph.Iterator) []*graph.Triple {
	var res ordered
	for {
		val, ok := it.Next()
		if !ok {
			break
		}
		res = append(res, ts.Triple(val))
	}
	sort.Sort(res)
	return res
}

func LoadTriplesInto(tChan chan *graph.Triple, ts graph.TripleStore, loadSize int) {
	tripleblock := make([]*graph.Triple, loadSize)
	i := 0
	for t := range tChan {
		tripleblock[i] = t
		i++
		if i == loadSize {
			ts.AddTripleSet(tripleblock)
			i = 0
		}
	}
	ts.AddTripleSet(tripleblock[0:i])
}

func LoadTriplesFromFileInto(ts graph.TripleStore, filename string, loadSize int) {
	tChan := make(chan *graph.Triple)
	go ReadTriplesFromFile(tChan, filename)
	tripleblock := make([]*graph.Triple, loadSize)
	i := 0
	for t := range tChan {
		tripleblock[i] = t
		i++
		if i == loadSize {
			ts.AddTripleSet(tripleblock)
			i = 0
		}
	}
	ts.AddTripleSet(tripleblock[0:i])
}

func Load(ts graph.TripleStore, cfg *config.Config, path string) error {
	f, err := os.Open(path)
	if err != nil {
		return fmt.Errorf("could not open file %q: %v", path, err)
	}
	defer f.Close()

	r, err := decompressor(f)
	if err != nil {
		glog.Fatalln(err)
	}

	dec := cquads.NewDecoder(r)

	bulker, canBulk := ts.(graph.BulkLoader)
	if canBulk {
		err = bulker.BulkLoad(dec)
		if err == nil {
			return nil
		}
		if err == graph.ErrCannotBulkLoad {
			err = nil
		}
	}
	if err != nil {
		return err
	}

	block := make([]*quad.Quad, 0, cfg.LoadSize)
	for {
		t, err := dec.Unmarshal()
		if err != nil {
			if err == io.EOF {
				break
			}
			return err
		}
		block = append(block, t)
		if len(block) == cap(block) {
			ts.AddTripleSet(block)
			block = block[:0]
		}
	}
	ts.AddTripleSet(block)

	return nil
}

func hasaWithTag(ts graph.TripleStore, tag string, target string) *HasA {
	and := NewAnd()

	obj := ts.FixedIterator()
	obj.Add(ts.ValueOf(target))
	obj.Tagger().Add(tag)
	and.AddSubIterator(NewLinksTo(ts, obj, quad.Object))

	pred := ts.FixedIterator()
	pred.Add(ts.ValueOf("status"))
	and.AddSubIterator(NewLinksTo(ts, pred, quad.Predicate))

	return NewHasA(ts, and, quad.Subject)
}

func buildInOutIterator(obj *otto.Object, ts graph.TripleStore, base graph.Iterator, isReverse bool) graph.Iterator {
	argList, _ := obj.Get("_gremlin_values")
	if argList.Class() != "GoArray" {
		glog.Errorln("How is arglist not an array? Return nothing.", argList.Class())
		return graph.NewNullIterator()
	}
	argArray := argList.Object()
	lengthVal, _ := argArray.Get("length")
	length, _ := lengthVal.ToInteger()
	var predicateNodeIterator graph.Iterator
	if length == 0 {
		predicateNodeIterator = ts.GetNodesAllIterator()
	} else {
		zero, _ := argArray.Get("0")
		predicateNodeIterator = buildIteratorFromValue(zero, ts)
	}
	if length >= 2 {
		var tags []string
		one, _ := argArray.Get("1")
		if one.IsString() {
			s, _ := one.ToString()
			tags = append(tags, s)
		} else if one.Class() == "Array" {
			tags = makeListOfStringsFromArrayValue(one.Object())
		}
		for _, tag := range tags {
			predicateNodeIterator.AddTag(tag)
		}
	}

	in, out := graph.Subject, graph.Object
	if isReverse {
		in, out = out, in
	}
	lto := graph.NewLinksToIterator(ts, base, in)
	and := graph.NewAndIterator()
	and.AddSubIterator(graph.NewLinksToIterator(ts, predicateNodeIterator, graph.Predicate))
	and.AddSubIterator(lto)
	return graph.NewHasaIterator(ts, and, out)
}

func buildHasaWithTag(ts graph.TripleStore, tag string, target string) *HasA {
	fixed_obj := ts.FixedIterator()
	fixed_pred := ts.FixedIterator()
	fixed_obj.Add(ts.ValueOf(target))
	fixed_pred.Add(ts.ValueOf("status"))
	fixed_obj.AddTag(tag)
	lto1 := NewLinksTo(ts, fixed_obj, graph.Object)
	lto2 := NewLinksTo(ts, fixed_pred, graph.Predicate)
	and := NewAnd()
	and.AddSubIterator(lto1)
	and.AddSubIterator(lto2)
	hasa := NewHasA(ts, and, graph.Subject)
	return hasa
}

func main() {
	// No command? It's time for usage.
	if len(os.Args) == 1 {
		Usage()
		os.Exit(1)
	}
	cmd := os.Args[1]
	newargs := make([]string, 0)
	newargs = append(newargs, os.Args[0])
	newargs = append(newargs, os.Args[2:]...)
	os.Args = newargs
	flag.Parse()
	var ts graph.TripleStore
	cfg := config.ParseConfigFromFlagsAndFile(*configFile)
	if os.Getenv("GOMAXPROCS") == "" {
		runtime.GOMAXPROCS(runtime.NumCPU())
		glog.Infoln("Setting GOMAXPROCS to", runtime.NumCPU())
	} else {
		glog.Infoln("GOMAXPROCS currently", os.Getenv("GOMAXPROCS"), " -- not adjusting")
	}
	switch cmd {
	case "init":
		db.Init(cfg, *tripleFile)
	case "load":
		ts = db.Open(cfg)
		db.Load(ts, cfg, *tripleFile, false)
		ts.Close()
	case "repl":
		ts = db.Open(cfg)
		db.Repl(ts, *queryLanguage, cfg)
		ts.Close()
	case "http":
		ts = db.Open(cfg)
		http.Serve(ts, cfg)
		ts.Close()
	default:
		fmt.Println("No command", cmd)
		flag.Usage()
	}
}

func Repl(ts graph.TripleStore, queryLanguage string, cfg *config.Config) error {
	var ses query.Session
	switch queryLanguage {
	case "sexp":
		ses = sexp.NewSession(ts)
	case "mql":
		ses = mql.NewSession(ts)
	case "gremlin":
		fallthrough
	default:
		ses = gremlin.NewSession(ts, cfg.Timeout, true)
	}
	buf := bufio.NewReader(os.Stdin)
	var line []byte
	for {
		if len(line) == 0 {
			fmt.Print("cayley> ")
		} else {
			fmt.Print("...       ")
		}
		l, prefix, err := buf.ReadLine()
		if err == io.EOF {
			if len(line) != 0 {
				line = line[:0]
			} else {
				return nil
			}
		}
		if err != nil {
			line = line[:0]
		}
		if prefix {
			return errors.New("line too long")
		}
		line = append(line, l...)
		if len(line) == 0 {
			continue
		}
		line = bytes.TrimSpace(line)
		if len(line) == 0 || line[0] == '#' {
			line = line[:0]
			continue
		}
		if bytes.HasPrefix(line, []byte(":debug")) {
			ses.ToggleDebug()
			fmt.Println("Debug Toggled")
			line = line[:0]
			continue
		}
		if bytes.HasPrefix(line, []byte(":a")) {
			var tripleStmt = line[3:]
			triple, err := cquads.Parse(string(tripleStmt))
			if !triple.IsValid() {
				if err != nil {
					fmt.Printf("not a valid triple: %v\n", err)
				}
				line = line[:0]
				continue
			}
			ts.AddTriple(triple)
			line = line[:0]
			continue
		}
		if bytes.HasPrefix(line, []byte(":d")) {
			var tripleStmt = line[3:]
			triple, err := cquads.Parse(string(tripleStmt))
			if !triple.IsValid() {
				if err != nil {
					fmt.Printf("not a valid triple: %v\n", err)
				}
				line = line[:0]
				continue
			}
			ts.RemoveTriple(triple)
			line = line[:0]
			continue
		}
		result, err := ses.InputParses(string(line))
		switch result {
		case query.Parsed:
			Run(string(line), ses)
			line = line[:0]
		case query.ParseFail:
			fmt.Println("Error: ", err)
			line = line[:0]
		case query.ParseMore:
		}
	}
}

func buildIteratorFromValue(val otto.Value, ts graph.TripleStore) graph.Iterator {
	if val.IsNull() || val.IsUndefined() {
		return ts.GetNodesAllIterator()
	}
	if val.IsPrimitive() {
		thing, _ := val.Export()
		switch v := thing.(type) {
		case string:
			it := ts.MakeFixed()
			it.AddValue(ts.GetIdFor(v))
			return it
		default:
			glog.Errorln("Trying to build unknown primitive value.")
		}
	}
	switch val.Class() {
	case "Object":
		return buildIteratorTree(val.Object(), ts)
	case "Array":
		// Had better be an array of strings
		strings := makeListOfStringsFromArrayValue(val.Object())
		it := ts.MakeFixed()
		for _, x := range strings {
			it.AddValue(ts.GetIdFor(x))
		}
		return it
	case "Number":
		fallthrough
	case "Boolean":
		fallthrough
	case "Date":
		fallthrough
	case "String":
		it := ts.MakeFixed()
		str, _ := val.ToString()
		it.AddValue(ts.GetIdFor(str))
		return it
	default:
		glog.Errorln("Trying to handle unsupported Javascript value.")
		return graph.NewNullIterator()
	}
}

func buildIteratorTreeHelper(obj *otto.Object, ts graph.TripleStore, base graph.Iterator) graph.Iterator {
	var it graph.Iterator
	it = base
	// TODO: Better error handling
	kindVal, _ := obj.Get("_gremlin_type")
	stringArgs := getStringArgs(obj)
	var subIt graph.Iterator
	prevVal, _ := obj.Get("_gremlin_prev")
	if !prevVal.IsObject() {
		subIt = base
	} else {
		subIt = buildIteratorTreeHelper(prevVal.Object(), ts, base)
	}

	kind, _ := kindVal.ToString()
	switch kind {
	case "vertex":
		if len(stringArgs) == 0 {
			it = ts.GetNodesAllIterator()
		} else {
			fixed := ts.MakeFixed()
			for _, name := range stringArgs {
				fixed.AddValue(ts.GetIdFor(name))
			}
			it = fixed
		}
	case "tag":
		it = subIt
		for _, tag := range stringArgs {
			it.AddTag(tag)
		}
	case "save":
		all := ts.GetNodesAllIterator()
		if len(stringArgs) > 2 || len(stringArgs) == 0 {
			return graph.NewNullIterator()
		}
		if len(stringArgs) == 2 {
			all.AddTag(stringArgs[1])
		} else {
			all.AddTag(stringArgs[0])
		}
		predFixed := ts.MakeFixed()
		predFixed.AddValue(ts.GetIdFor(stringArgs[0]))
		subAnd := graph.NewAndIterator()
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, predFixed, graph.Predicate))
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, all, graph.Object))
		hasa := graph.NewHasaIterator(ts, subAnd, graph.Subject)
		and := graph.NewAndIterator()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "saver":
		all := ts.GetNodesAllIterator()
		if len(stringArgs) > 2 || len(stringArgs) == 0 {
			return graph.NewNullIterator()
		}
		if len(stringArgs) == 2 {
			all.AddTag(stringArgs[1])
		} else {
			all.AddTag(stringArgs[0])
		}
		predFixed := ts.MakeFixed()
		predFixed.AddValue(ts.GetIdFor(stringArgs[0]))
		subAnd := graph.NewAndIterator()
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, predFixed, graph.Predicate))
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, all, graph.Subject))
		hasa := graph.NewHasaIterator(ts, subAnd, graph.Object)
		and := graph.NewAndIterator()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "has":
		fixed := ts.MakeFixed()
		if len(stringArgs) < 2 {
			return graph.NewNullIterator()
		}
		for _, name := range stringArgs[1:] {
			fixed.AddValue(ts.GetIdFor(name))
		}
		predFixed := ts.MakeFixed()
		predFixed.AddValue(ts.GetIdFor(stringArgs[0]))
		subAnd := graph.NewAndIterator()
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, predFixed, graph.Predicate))
		subAnd.AddSubIterator(graph.NewLinksToIterator(ts, fixed, graph.Object))
		hasa := graph.NewHasaIterator(ts, subAnd, graph.Subject)
		and := graph.NewAndIterator()
		and.AddSubIterator(hasa)
		and.AddSubIterator(subIt)
		it = and
	case "morphism":
		it = base
	case "and":
		arg, _ := obj.Get("_gremlin_values")
		firstArg, _ := arg.Object().Get("0")
		if !isVertexChain(firstArg.Object()) {
			return graph.NewNullIterator()
		}
		argIt := buildIteratorTree(firstArg.Object(), ts)

		and := graph.NewAndIterator()
//.........这里部分代码省略.........