Merge pull request #145 from kortschak/gremlin

Fix gremlin timeout handling

query/gremlin/build_iterator.go

@@ -25,20 +25,14 @@ import (
 	"github.com/google/cayley/quad"
 )
 
-func getStrings(obj *otto.Object, field string) []string {
+func propertiesOf(obj *otto.Object, name string) []string {
-	strings := make([]string, 0)
+	val, _ := obj.Get(name)
-	val, _ := obj.Get(field)
+	if val.IsUndefined() {
-	if !val.IsUndefined() {
+		return nil
+	}
 	export, _ := val.Export()
-		array := export.([]interface{})
+	return export.([]string)
-		for _, arg := range array {
-			strings = append(strings, arg.(string))
 }
-	}
-	return strings
-}
-
-func getStringArgs(obj *otto.Object) []string { return getStrings(obj, "string_args") }
 
 func buildIteratorTree(obj *otto.Object, ts graph.TripleStore) graph.Iterator {
 	if !isVertexChain(obj) {
@@ -47,22 +41,18 @@ func buildIteratorTree(obj *otto.Object, ts graph.TripleStore) graph.Iterator {
 	return buildIteratorTreeHelper(obj, ts, iterator.NewNull())
 }
 
-func makeListOfStringsFromArrayValue(obj *otto.Object) []string {
+func stringsFrom(obj *otto.Object) []string {
 	var output []string
 	lengthValue, _ := obj.Get("length")
 	length, _ := lengthValue.ToInteger()
 	ulength := uint32(length)
-	for index := uint32(0); index < ulength; index += 1 {
+	for i := uint32(0); i < ulength; i++ {
-		name := strconv.FormatInt(int64(index), 10)
+		name := strconv.FormatInt(int64(i), 10)
 		value, err := obj.Get(name)
-		if err != nil {
+		if err != nil || !value.IsString() {
 			continue
 		}
-		if !value.IsString() {
+		output = append(output, value.String())
-			continue
-		}
-		s, _ := value.ToString()
-		output = append(output, s)
 	}
 	return output
 }
@@ -87,7 +77,7 @@ func buildIteratorFromValue(val otto.Value, ts graph.TripleStore) graph.Iterator
 		return buildIteratorTree(val.Object(), ts)
 	case "Array":
 		// Had better be an array of strings
-		strings := makeListOfStringsFromArrayValue(val.Object())
+		strings := stringsFrom(val.Object())
 		it := ts.FixedIterator()
 		for _, x := range strings {
 			it.Add(ts.ValueOf(x))
@@ -101,8 +91,7 @@ func buildIteratorFromValue(val otto.Value, ts graph.TripleStore) graph.Iterator
 		fallthrough
 	case "String":
 		it := ts.FixedIterator()
-		str, _ := val.ToString()
+		it.Add(ts.ValueOf(val.String()))
-		it.Add(ts.ValueOf(str))
 		return it
 	default:
 		glog.Errorln("Trying to handle unsupported Javascript value.")
@@ -130,10 +119,9 @@ func buildInOutIterator(obj *otto.Object, ts graph.TripleStore, base graph.Itera
 		var tags []string
 		one, _ := argArray.Get("1")
 		if one.IsString() {
-			s, _ := one.ToString()
+			tags = append(tags, one.String())
-			tags = append(tags, s)
 		} else if one.Class() == "Array" {
-			tags = makeListOfStringsFromArrayValue(one.Object())
+			tags = stringsFrom(one.Object())
 		}
 		for _, tag := range tags {
 			predicateNodeIterator.Tagger().Add(tag)
@@ -152,21 +140,19 @@ func buildInOutIterator(obj *otto.Object, ts graph.TripleStore, base graph.Itera
 }
 
 func buildIteratorTreeHelper(obj *otto.Object, ts graph.TripleStore, base graph.Iterator) graph.Iterator {
-	var it graph.Iterator
+	var it graph.Iterator = base
-	it = base
+
 	// TODO: Better error handling
-	kindVal, _ := obj.Get("_gremlin_type")
-	stringArgs := getStringArgs(obj)
 	var subIt graph.Iterator
-	prevVal, _ := obj.Get("_gremlin_prev")
+	if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
-	if !prevVal.IsObject() {
 		subIt = base
 	} else {
-		subIt = buildIteratorTreeHelper(prevVal.Object(), ts, base)
+		subIt = buildIteratorTreeHelper(prev.Object(), ts, base)
 	}
 
-	kind, _ := kindVal.ToString()
+	stringArgs := propertiesOf(obj, "string_args")
-	switch kind {
+	val, _ := obj.Get("_gremlin_type")
+	switch val.String() {
 	case "vertex":
 		if len(stringArgs) == 0 {
 			it = ts.NodesAllIterator()

query/gremlin/environ.go

@@ -17,46 +17,38 @@ package gremlin
 // Builds a new Gremlin environment pointing at a session.
 
 import (
+	"sync"
+
 	"github.com/barakmich/glog"
 	"github.com/robertkrimen/otto"
+
+	"github.com/google/cayley/graph"
 )
 
-func BuildEnviron(ses *Session) *otto.Otto {
+type worker struct {
+	ts  graph.TripleStore
+	env *otto.Otto
+	sync.Mutex
+
+	results chan interface{}
+	shape   map[string]interface{}
+
+	count int
+	limit int
+
+	kill <-chan struct{}
+}
+
+func newWorker(ts graph.TripleStore) *worker {
 	env := otto.New()
-	setupGremlin(env, ses)
+	wk := &worker{
-	return env
+		ts:    ts,
+		env:   env,
+		limit: -1,
 	}
-
-func concatStringArgs(call otto.FunctionCall) *[]interface{} {
-	outStrings := make([]interface{}, 0)
-	for _, arg := range call.ArgumentList {
-		if arg.IsString() {
-			outStrings = append(outStrings, arg.String())
-		}
-		if arg.IsObject() && arg.Class() == "Array" {
-			obj, _ := arg.Export()
-			for _, x := range obj.([]interface{}) {
-				outStrings = append(outStrings, x.(string))
-			}
-		}
-	}
-	return &outStrings
-}
-
-func isVertexChain(obj *otto.Object) bool {
-	val, _ := obj.Get("_gremlin_type")
-	if x, _ := val.ToString(); x == "vertex" {
-		return true
-	}
-	val, _ = obj.Get("_gremlin_prev")
-	if val.IsObject() {
-		return isVertexChain(val.Object())
-	}
-	return false
-}
-
-func setupGremlin(env *otto.Otto, ses *Session) {
 	graph, _ := env.Object("graph = {}")
+	env.Run("g = graph")
+
 	graph.Set("Vertex", func(call otto.FunctionCall) otto.Value {
 		call.Otto.Run("var out = {}")
 		out, err := call.Otto.Object("out")
@@ -65,31 +57,64 @@ func setupGremlin(env *otto.Otto, ses *Session) {
 			return otto.TrueValue()
 		}
 		out.Set("_gremlin_type", "vertex")
-		outStrings := concatStringArgs(call)
+		args := argsOf(call)
-		if len(*outStrings) > 0 {
+		if len(args) > 0 {
-			out.Set("string_args", *outStrings)
+			out.Set("string_args", args)
 		}
-		embedTraversals(env, ses, out)
+		wk.embedTraversals(env, out)
-		embedFinals(env, ses, out)
+		wk.embedFinals(env, out)
 		return out.Value()
 	})
+	env.Run("graph.V = graph.Vertex")
 
 	graph.Set("Morphism", func(call otto.FunctionCall) otto.Value {
 		call.Otto.Run("var out = {}")
 		out, _ := call.Otto.Object("out")
 		out.Set("_gremlin_type", "morphism")
-		embedTraversals(env, ses, out)
+		wk.embedTraversals(env, out)
 		return out.Value()
 	})
+	env.Run("graph.M = graph.Morphism")
+
 	graph.Set("Emit", func(call otto.FunctionCall) otto.Value {
 		value := call.Argument(0)
 		if value.IsDefined() {
-			ses.SendResult(&Result{val: &value})
+			wk.send(&Result{val: &value})
 		}
 		return otto.NullValue()
 	})
-	env.Run("graph.V = graph.Vertex")
-	env.Run("graph.M = graph.Morphism")
-	env.Run("g = graph")
 
+	return wk
+}
+
+func (wk *worker) wantShape() bool {
+	return wk.shape != nil
+}
+
+func argsOf(call otto.FunctionCall) []string {
+	var out []string
+	for _, arg := range call.ArgumentList {
+		if arg.IsString() {
+			out = append(out, arg.String())
+		}
+		if arg.IsObject() && arg.Class() == "Array" {
+			obj, _ := arg.Export()
+			for _, x := range obj.([]interface{}) {
+				out = append(out, x.(string))
+			}
+		}
+	}
+	return out
+}
+
+func isVertexChain(obj *otto.Object) bool {
+	val, _ := obj.Get("_gremlin_type")
+	if val.String() == "vertex" {
+		return true
+	}
+	val, _ = obj.Get("_gremlin_prev")
+	if val.IsObject() {
+		return isVertexChain(val.Object())
+	}
+	return false
 }

query/gremlin/finals.go

@@ -26,45 +26,45 @@ import (
 
 const TopResultTag = "id"
 
-func embedFinals(env *otto.Otto, ses *Session, obj *otto.Object) {
+func (wk *worker) embedFinals(env *otto.Otto, obj *otto.Object) {
-	obj.Set("All", allFunc(env, ses, obj))
+	obj.Set("All", wk.allFunc(env, obj))
-	obj.Set("GetLimit", limitFunc(env, ses, obj))
+	obj.Set("GetLimit", wk.limitFunc(env, obj))
-	obj.Set("ToArray", toArrayFunc(env, ses, obj, false))
+	obj.Set("ToArray", wk.toArrayFunc(env, obj, false))
-	obj.Set("ToValue", toValueFunc(env, ses, obj, false))
+	obj.Set("ToValue", wk.toValueFunc(env, obj, false))
-	obj.Set("TagArray", toArrayFunc(env, ses, obj, true))
+	obj.Set("TagArray", wk.toArrayFunc(env, obj, true))
-	obj.Set("TagValue", toValueFunc(env, ses, obj, true))
+	obj.Set("TagValue", wk.toValueFunc(env, obj, true))
-	obj.Set("Map", mapFunc(env, ses, obj))
+	obj.Set("Map", wk.mapFunc(env, obj))
-	obj.Set("ForEach", mapFunc(env, ses, obj))
+	obj.Set("ForEach", wk.mapFunc(env, obj))
 }
 
-func allFunc(env *otto.Otto, ses *Session, obj *otto.Object) func(otto.FunctionCall) otto.Value {
+func (wk *worker) allFunc(env *otto.Otto, obj *otto.Object) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
-		it := buildIteratorTree(obj, ses.ts)
+		it := buildIteratorTree(obj, wk.ts)
 		it.Tagger().Add(TopResultTag)
-		ses.limit = -1
+		wk.limit = -1
-		ses.count = 0
+		wk.count = 0
-		runIteratorOnSession(it, ses)
+		wk.runIterator(it)
 		return otto.NullValue()
 	}
 }
 
-func limitFunc(env *otto.Otto, ses *Session, obj *otto.Object) func(otto.FunctionCall) otto.Value {
+func (wk *worker) limitFunc(env *otto.Otto, obj *otto.Object) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
 		if len(call.ArgumentList) > 0 {
 			limitVal, _ := call.Argument(0).ToInteger()
-			it := buildIteratorTree(obj, ses.ts)
+			it := buildIteratorTree(obj, wk.ts)
 			it.Tagger().Add(TopResultTag)
-			ses.limit = int(limitVal)
+			wk.limit = int(limitVal)
-			ses.count = 0
+			wk.count = 0
-			runIteratorOnSession(it, ses)
+			wk.runIterator(it)
 		}
 		return otto.NullValue()
 	}
 }
 
-func toArrayFunc(env *otto.Otto, ses *Session, obj *otto.Object, withTags bool) func(otto.FunctionCall) otto.Value {
+func (wk *worker) toArrayFunc(env *otto.Otto, obj *otto.Object, withTags bool) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
-		it := buildIteratorTree(obj, ses.ts)
+		it := buildIteratorTree(obj, wk.ts)
 		it.Tagger().Add(TopResultTag)
 		limit := -1
 		if len(call.ArgumentList) > 0 {
@@ -74,10 +74,10 @@ func toArrayFunc(env *otto.Otto, ses *Session, obj *otto.Object, withTags bool)
 		var val otto.Value
 		var err error
 		if !withTags {
-			array := runIteratorToArrayNoTags(it, ses, limit)
+			array := wk.runIteratorToArrayNoTags(it, limit)
 			val, err = call.Otto.ToValue(array)
 		} else {
-			array := runIteratorToArray(it, ses, limit)
+			array := wk.runIteratorToArray(it, limit)
 			val, err = call.Otto.ToValue(array)
 		}
 
@@ -89,21 +89,21 @@ func toArrayFunc(env *otto.Otto, ses *Session, obj *otto.Object, withTags bool)
 	}
 }
 
-func toValueFunc(env *otto.Otto, ses *Session, obj *otto.Object, withTags bool) func(otto.FunctionCall) otto.Value {
+func (wk *worker) toValueFunc(env *otto.Otto, obj *otto.Object, withTags bool) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
-		it := buildIteratorTree(obj, ses.ts)
+		it := buildIteratorTree(obj, wk.ts)
 		it.Tagger().Add(TopResultTag)
 		limit := 1
 		var val otto.Value
 		var err error
 		if !withTags {
-			array := runIteratorToArrayNoTags(it, ses, limit)
+			array := wk.runIteratorToArrayNoTags(it, limit)
 			if len(array) < 1 {
 				return otto.NullValue()
 			}
 			val, err = call.Otto.ToValue(array[0])
 		} else {
-			array := runIteratorToArray(it, ses, limit)
+			array := wk.runIteratorToArray(it, limit)
 			if len(array) < 1 {
 				return otto.NullValue()
 			}
@@ -115,13 +115,12 @@ func toValueFunc(env *otto.Otto, ses *Session, obj *otto.Object, withTags bool)
 		} else {
 			return val
 		}
-
 	}
 }
 
-func mapFunc(env *otto.Otto, ses *Session, obj *otto.Object) func(otto.FunctionCall) otto.Value {
+func (wk *worker) mapFunc(env *otto.Otto, obj *otto.Object) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
-		it := buildIteratorTree(obj, ses.ts)
+		it := buildIteratorTree(obj, wk.ts)
 		it.Tagger().Add(TopResultTag)
 		limit := -1
 		if len(call.ArgumentList) == 0 {
@@ -132,26 +131,26 @@ func mapFunc(env *otto.Otto, ses *Session, obj *otto.Object) func(otto.FunctionC
 			limitParsed, _ := call.Argument(0).ToInteger()
 			limit = int(limitParsed)
 		}
-		runIteratorWithCallback(it, ses, callback, call, limit)
+		wk.runIteratorWithCallback(it, callback, call, limit)
 		return otto.NullValue()
 	}
 }
 
-func tagsToValueMap(m map[string]graph.Value, ses *Session) map[string]string {
+func (wk *worker) tagsToValueMap(m map[string]graph.Value) map[string]string {
 	outputMap := make(map[string]string)
 	for k, v := range m {
-		outputMap[k] = ses.ts.NameOf(v)
+		outputMap[k] = wk.ts.NameOf(v)
 	}
 	return outputMap
 }
 
-func runIteratorToArray(it graph.Iterator, ses *Session, limit int) []map[string]string {
+func (wk *worker) runIteratorToArray(it graph.Iterator, limit int) []map[string]string {
 	output := make([]map[string]string, 0)
-	count := 0
+	n := 0
 	it, _ = it.Optimize()
 	for {
 		select {
-		case <-ses.kill:
+		case <-wk.kill:
 			return nil
 		default:
 		}
@@ -160,22 +159,22 @@ func runIteratorToArray(it graph.Iterator, ses *Session, limit int) []map[string
 		}
 		tags := make(map[string]graph.Value)
 		it.TagResults(tags)
-		output = append(output, tagsToValueMap(tags, ses))
+		output = append(output, wk.tagsToValueMap(tags))
-		count++
+		n++
-		if limit >= 0 && count >= limit {
+		if limit >= 0 && n >= limit {
 			break
 		}
 		for it.NextPath() {
 			select {
-			case <-ses.kill:
+			case <-wk.kill:
 				return nil
 			default:
 			}
 			tags := make(map[string]graph.Value)
 			it.TagResults(tags)
-			output = append(output, tagsToValueMap(tags, ses))
+			output = append(output, wk.tagsToValueMap(tags))
-			count++
+			n++
-			if limit >= 0 && count >= limit {
+			if limit >= 0 && n >= limit {
 				break
 			}
 		}
@@ -184,22 +183,22 @@ func runIteratorToArray(it graph.Iterator, ses *Session, limit int) []map[string
 	return output
 }
 
-func runIteratorToArrayNoTags(it graph.Iterator, ses *Session, limit int) []string {
+func (wk *worker) runIteratorToArrayNoTags(it graph.Iterator, limit int) []string {
 	output := make([]string, 0)
-	count := 0
+	n := 0
 	it, _ = it.Optimize()
 	for {
 		select {
-		case <-ses.kill:
+		case <-wk.kill:
 			return nil
 		default:
 		}
 		if !graph.Next(it) {
 			break
 		}
-		output = append(output, ses.ts.NameOf(it.Result()))
+		output = append(output, wk.ts.NameOf(it.Result()))
-		count++
+		n++
-		if limit >= 0 && count >= limit {
+		if limit >= 0 && n >= limit {
 			break
 		}
 	}
@@ -207,13 +206,13 @@ func runIteratorToArrayNoTags(it graph.Iterator, ses *Session, limit int) []stri
 	return output
 }
 
-func runIteratorWithCallback(it graph.Iterator, ses *Session, callback otto.Value, this otto.FunctionCall, limit int) {
+func (wk *worker) runIteratorWithCallback(it graph.Iterator, callback otto.Value, this otto.FunctionCall, limit int) {
-	count := 0
+	n := 0
 	it, _ = it.Optimize()
 	glog.V(2).Infoln(it.DebugString(0))
 	for {
 		select {
-		case <-ses.kill:
+		case <-wk.kill:
 			return
 		default:
 		}
@@ -222,24 +221,24 @@ func runIteratorWithCallback(it graph.Iterator, ses *Session, callback otto.Valu
 		}
 		tags := make(map[string]graph.Value)
 		it.TagResults(tags)
-		val, _ := this.Otto.ToValue(tagsToValueMap(tags, ses))
+		val, _ := this.Otto.ToValue(wk.tagsToValueMap(tags))
 		val, _ = callback.Call(this.This, val)
-		count++
+		n++
-		if limit >= 0 && count >= limit {
+		if limit >= 0 && n >= limit {
 			break
 		}
 		for it.NextPath() {
 			select {
-			case <-ses.kill:
+			case <-wk.kill:
 				return
 			default:
 			}
 			tags := make(map[string]graph.Value)
 			it.TagResults(tags)
-			val, _ := this.Otto.ToValue(tagsToValueMap(tags, ses))
+			val, _ := this.Otto.ToValue(wk.tagsToValueMap(tags))
 			val, _ = callback.Call(this.This, val)
-			count++
+			n++
-			if limit >= 0 && count >= limit {
+			if limit >= 0 && n >= limit {
 				break
 			}
 		}
@@ -247,16 +246,37 @@ func runIteratorWithCallback(it graph.Iterator, ses *Session, callback otto.Valu
 	it.Close()
 }
 
-func runIteratorOnSession(it graph.Iterator, ses *Session) {
+func (wk *worker) send(r *Result) bool {
-	if ses.wantShape {
+	if wk.limit >= 0 && wk.limit == wk.count {
-		iterator.OutputQueryShapeForIterator(it, ses.ts, ses.shape)
+		return false
+	}
+	select {
+	case <-wk.kill:
+		return false
+	default:
+	}
+	if wk.results != nil {
+		wk.results <- r
+		wk.count++
+		if wk.limit >= 0 && wk.limit == wk.count {
+			return false
+		} else {
+			return true
+		}
+	}
+	return false
+}
+
+func (wk *worker) runIterator(it graph.Iterator) {
+	if wk.wantShape() {
+		iterator.OutputQueryShapeForIterator(it, wk.ts, wk.shape)
 		return
 	}
 	it, _ = it.Optimize()
 	glog.V(2).Infoln(it.DebugString(0))
 	for {
 		select {
-		case <-ses.kill:
+		case <-wk.kill:
 			return
 		default:
 		}
@@ -265,18 +285,18 @@ func runIteratorOnSession(it graph.Iterator, ses *Session) {
 		}
 		tags := make(map[string]graph.Value)
 		it.TagResults(tags)
-		if !ses.SendResult(&Result{actualResults: &tags}) {
+		if !wk.send(&Result{actualResults: tags}) {
 			break
 		}
 		for it.NextPath() {
 			select {
-			case <-ses.kill:
+			case <-wk.kill:
 				return
 			default:
 			}
 			tags := make(map[string]graph.Value)
 			it.TagResults(tags)
-			if !ses.SendResult(&Result{actualResults: &tags}) {
+			if !wk.send(&Result{actualResults: tags}) {
 				break
 			}
 		}

query/gremlin/gremlin_test.go

@@ -257,7 +257,7 @@ func runQueryGetTag(g []quad.Quad, query string, tag string) []string {
 	for res := range c {
 		data := res.(*Result)
 		if data.val == nil {
-			val := (*data.actualResults)[tag]
+			val := data.actualResults[tag]
 			if val != nil {
 				results = append(results, js.ts.NameOf(val))
 			}

query/gremlin/session.go

@@ -18,7 +18,6 @@ import (
 	"errors"
 	"fmt"
 	"sort"
-	"sync"
 	"time"
 
 	"github.com/robertkrimen/otto"
@@ -32,31 +31,28 @@ var ErrKillTimeout = errors.New("query timed out")
 
 type Session struct {
 	ts graph.TripleStore
-	results    chan interface{}
+
-	env        *otto.Otto
+	wk      *worker
-	envLock    sync.Mutex
-	debug      bool
-	limit      int
-	count      int
-	dataOutput []interface{}
-	wantShape  bool
-	shape      map[string]interface{}
-	err        error
 	script  *otto.Script
-	kill       chan struct{}
+	persist *otto.Otto
+
 	timeout time.Duration
-	emptyEnv   *otto.Otto
+	kill    chan struct{}
+
+	debug      bool
+	dataOutput []interface{}
+
+	err error
 }
 
 func NewSession(ts graph.TripleStore, timeout time.Duration, persist bool) *Session {
 	g := Session{
 		ts:      ts,
-		limit:   -1,
+		wk:      newWorker(ts),
 		timeout: timeout,
 	}
-	g.env = BuildEnviron(&g)
 	if persist {
-		g.emptyEnv = g.env
+		g.persist = g.wk.env
 	}
 	return &g
 }
@@ -65,7 +61,7 @@ type Result struct {
 	metaresult    bool
 	err           error
 	val           *otto.Value
-	actualResults *map[string]graph.Value
+	actualResults map[string]graph.Value
 }
 
 func (s *Session) ToggleDebug() {
@@ -74,15 +70,14 @@ func (s *Session) ToggleDebug() {
 
 func (s *Session) GetQuery(input string, out chan map[string]interface{}) {
 	defer close(out)
-	s.shape = make(map[string]interface{})
+	s.wk.shape = make(map[string]interface{})
-	s.wantShape = true
+	s.wk.env.Run(input)
-	s.env.Run(input)
+	out <- s.wk.shape
-	out <- s.shape
+	s.wk.shape = nil
-	s.shape = nil
 }
 
 func (s *Session) InputParses(input string) (query.ParseResult, error) {
-	script, err := s.env.Compile("", input)
+	script, err := s.wk.env.Compile("", input)
 	if err != nil {
 		return query.ParseFail, err
 	}
@@ -90,35 +85,13 @@ func (s *Session) InputParses(input string) (query.ParseResult, error) {
 	return query.Parsed, nil
 }
 
-func (s *Session) SendResult(r *Result) bool {
-	if s.limit >= 0 && s.limit == s.count {
-		return false
-	}
-	s.envLock.Lock()
-	kill := s.kill
-	s.envLock.Unlock()
-	select {
-	case <-kill:
-		return false
-	default:
-	}
-	if s.results != nil {
-		s.results <- r
-		s.count++
-		if s.limit >= 0 && s.limit == s.count {
-			return false
-		} else {
-			return true
-		}
-	}
-	return false
-}
-
 func (s *Session) runUnsafe(input interface{}) (otto.Value, error) {
+	wk := s.wk
 	defer func() {
 		if r := recover(); r != nil {
 			if r == ErrKillTimeout {
 				s.err = ErrKillTimeout
+				wk.env = s.persist
 				return
 			}
 			panic(r)
@@ -126,49 +99,40 @@ func (s *Session) runUnsafe(input interface{}) (otto.Value, error) {
 	}()
 
 	// Use buffered chan to prevent blocking.
-	s.env.Interrupt = make(chan func(), 1)
+	wk.env.Interrupt = make(chan func(), 1)
+	s.kill = make(chan struct{})
+	wk.kill = s.kill
 
-	ready := make(chan struct{})
 	done := make(chan struct{})
+	defer close(done)
 	if s.timeout >= 0 {
 		go func() {
 			time.Sleep(s.timeout)
-			<-ready
 			select {
 			case <-done:
-				return
 			default:
 				close(s.kill)
-				s.envLock.Lock()
+				wk.Lock()
-				defer s.envLock.Unlock()
+				if wk.env != nil {
-				s.kill = nil
+					wk.env.Interrupt <- func() {
-				if s.env != nil {
-					s.env.Interrupt <- func() {
 						panic(ErrKillTimeout)
 					}
-					s.env = s.emptyEnv
 				}
-				return
+				wk.Unlock()
 			}
 		}()
 	}
 
-	s.envLock.Lock()
+	wk.Lock()
-	env := s.env
+	env := wk.env
-	if s.kill == nil {
+	wk.Unlock()
-		s.kill = make(chan struct{})
+	return env.Run(input)
-	}
-	s.envLock.Unlock()
-	close(ready)
-	out, err := env.Run(input)
-	close(done)
-	return out, err
 }
 
-func (s *Session) ExecInput(input string, out chan interface{}, limit int) {
+func (s *Session) ExecInput(input string, out chan interface{}, _ int) {
 	defer close(out)
 	s.err = nil
-	s.results = out
+	s.wk.results = out
 	var err error
 	var value otto.Value
 	if s.script == nil {
@@ -181,11 +145,11 @@ func (s *Session) ExecInput(input string, out chan interface{}, limit int) {
 		err:        err,
 		val:        &value,
 	}
-	s.results = nil
+	s.wk.results = nil
 	s.script = nil
-	s.envLock.Lock()
+	s.wk.Lock()
-	s.env = s.emptyEnv
+	s.wk.env = s.persist
-	s.envLock.Unlock()
+	s.wk.Unlock()
 }
 
 func (s *Session) ToText(result interface{}) string {
@@ -210,9 +174,9 @@ func (s *Session) ToText(result interface{}) string {
 	out = fmt.Sprintln("****")
 	if data.val == nil {
 		tags := data.actualResults
-		tagKeys := make([]string, len(*tags))
+		tagKeys := make([]string, len(tags))
 		i := 0
-		for k, _ := range *tags {
+		for k, _ := range tags {
 			tagKeys[i] = k
 			i++
 		}
@@ -221,7 +185,7 @@ func (s *Session) ToText(result interface{}) string {
 			if k == "$_" {
 				continue
 			}
-			out += fmt.Sprintf("%s : %s\n", k, s.ts.NameOf((*tags)[k]))
+			out += fmt.Sprintf("%s : %s\n", k, s.ts.NameOf(tags[k]))
 		}
 	} else {
 		if data.val.IsObject() {
@@ -245,15 +209,15 @@ func (s *Session) BuildJson(result interface{}) {
 		if data.val == nil {
 			obj := make(map[string]string)
 			tags := data.actualResults
-			tagKeys := make([]string, len(*tags))
+			tagKeys := make([]string, len(tags))
 			i := 0
-			for k, _ := range *tags {
+			for k, _ := range tags {
 				tagKeys[i] = k
 				i++
 			}
 			sort.Strings(tagKeys)
 			for _, k := range tagKeys {
-				obj[k] = s.ts.NameOf((*tags)[k])
+				obj[k] = s.ts.NameOf(tags[k])
 			}
 			s.dataOutput = append(s.dataOutput, obj)
 		} else {
@@ -273,11 +237,8 @@ func (s *Session) GetJson() ([]interface{}, error) {
 	if s.err != nil {
 		return nil, s.err
 	}
-	s.envLock.Lock()
-	kill := s.kill
-	s.envLock.Unlock()
 	select {
-	case <-kill:
+	case <-s.kill:
 		return nil, ErrKillTimeout
 	default:
 		return s.dataOutput, nil

query/gremlin/traversals.go

@@ -21,123 +21,121 @@ import (
 	"github.com/robertkrimen/otto"
 )
 
-func embedTraversals(env *otto.Otto, ses *Session, obj *otto.Object) {
+func (wk *worker) embedTraversals(env *otto.Otto, obj *otto.Object) {
-	obj.Set("In", gremlinFunc("in", obj, env, ses))
+	obj.Set("In", wk.gremlinFunc("in", obj, env))
-	obj.Set("Out", gremlinFunc("out", obj, env, ses))
+	obj.Set("Out", wk.gremlinFunc("out", obj, env))
-	obj.Set("Is", gremlinFunc("is", obj, env, ses))
+	obj.Set("Is", wk.gremlinFunc("is", obj, env))
-	obj.Set("Both", gremlinFunc("both", obj, env, ses))
+	obj.Set("Both", wk.gremlinFunc("both", obj, env))
-	obj.Set("Follow", gremlinFunc("follow", obj, env, ses))
+	obj.Set("Follow", wk.gremlinFunc("follow", obj, env))
-	obj.Set("FollowR", gremlinFollowR("followr", obj, env, ses))
+	obj.Set("FollowR", wk.gremlinFollowR("followr", obj, env))
-	obj.Set("And", gremlinFunc("and", obj, env, ses))
+	obj.Set("And", wk.gremlinFunc("and", obj, env))
-	obj.Set("Intersect", gremlinFunc("and", obj, env, ses))
+	obj.Set("Intersect", wk.gremlinFunc("and", obj, env))
-	obj.Set("Union", gremlinFunc("or", obj, env, ses))
+	obj.Set("Union", wk.gremlinFunc("or", obj, env))
-	obj.Set("Or", gremlinFunc("or", obj, env, ses))
+	obj.Set("Or", wk.gremlinFunc("or", obj, env))
-	obj.Set("Back", gremlinBack("back", obj, env, ses))
+	obj.Set("Back", wk.gremlinBack("back", obj, env))
-	obj.Set("Tag", gremlinFunc("tag", obj, env, ses))
+	obj.Set("Tag", wk.gremlinFunc("tag", obj, env))
-	obj.Set("As", gremlinFunc("tag", obj, env, ses))
+	obj.Set("As", wk.gremlinFunc("tag", obj, env))
-	obj.Set("Has", gremlinFunc("has", obj, env, ses))
+	obj.Set("Has", wk.gremlinFunc("has", obj, env))
-	obj.Set("Save", gremlinFunc("save", obj, env, ses))
+	obj.Set("Save", wk.gremlinFunc("save", obj, env))
-	obj.Set("SaveR", gremlinFunc("saver", obj, env, ses))
+	obj.Set("SaveR", wk.gremlinFunc("saver", obj, env))
 }
 
-func gremlinFunc(kind string, prevObj *otto.Object, env *otto.Otto, ses *Session) func(otto.FunctionCall) otto.Value {
+func (wk *worker) gremlinFunc(kind string, prev *otto.Object, env *otto.Otto) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
 		call.Otto.Run("var out = {}")
 		out, _ := call.Otto.Object("out")
 		out.Set("_gremlin_type", kind)
 		out.Set("_gremlin_values", call.ArgumentList)
-		out.Set("_gremlin_prev", prevObj)
+		out.Set("_gremlin_prev", prev)
-		outStrings := concatStringArgs(call)
+		args := argsOf(call)
-		if len(*outStrings) > 0 {
+		if len(args) > 0 {
-			out.Set("string_args", *outStrings)
+			out.Set("string_args", args)
 		}
-		embedTraversals(env, ses, out)
+		wk.embedTraversals(env, out)
 		if isVertexChain(call.This.Object()) {
-			embedFinals(env, ses, out)
+			wk.embedFinals(env, out)
 		}
 		return out.Value()
 	}
 }
 
-func gremlinBack(kind string, prevObj *otto.Object, env *otto.Otto, ses *Session) func(otto.FunctionCall) otto.Value {
+func (wk *worker) gremlinBack(kind string, prev *otto.Object, env *otto.Otto) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
 		call.Otto.Run("var out = {}")
 		out, _ := call.Otto.Object("out")
 		out.Set("_gremlin_type", kind)
 		out.Set("_gremlin_values", call.ArgumentList)
-		outStrings := concatStringArgs(call)
+		args := argsOf(call)
-		if len(*outStrings) > 0 {
+		if len(args) > 0 {
-			out.Set("string_args", *outStrings)
+			out.Set("string_args", args)
 		}
 		var otherChain *otto.Object
 		var thisObj *otto.Object
-		if len(*outStrings) != 0 {
+		if len(args) != 0 {
-			otherChain, thisObj = reverseGremlinChainTo(call.Otto, prevObj, (*outStrings)[0].(string))
+			otherChain, thisObj = reverseGremlinChainTo(call.Otto, prev, args[0])
 		} else {
-			otherChain, thisObj = reverseGremlinChainTo(call.Otto, prevObj, "")
+			otherChain, thisObj = reverseGremlinChainTo(call.Otto, prev, "")
 		}
 		out.Set("_gremlin_prev", thisObj)
 		out.Set("_gremlin_back_chain", otherChain)
-		embedTraversals(env, ses, out)
+		wk.embedTraversals(env, out)
 		if isVertexChain(call.This.Object()) {
-			embedFinals(env, ses, out)
+			wk.embedFinals(env, out)
 		}
 		return out.Value()
-
 	}
 }
 
-func gremlinFollowR(kind string, prevObj *otto.Object, env *otto.Otto, ses *Session) func(otto.FunctionCall) otto.Value {
+func (wk *worker) gremlinFollowR(kind string, prev *otto.Object, env *otto.Otto) func(otto.FunctionCall) otto.Value {
 	return func(call otto.FunctionCall) otto.Value {
 		call.Otto.Run("var out = {}")
 		out, _ := call.Otto.Object("out")
 		out.Set("_gremlin_type", kind)
 		out.Set("_gremlin_values", call.ArgumentList)
-		outStrings := concatStringArgs(call)
+		args := argsOf(call)
-		if len(*outStrings) > 0 {
+		if len(args) > 0 {
-			out.Set("string_args", *outStrings)
+			out.Set("string_args", args)
 		}
 		if len(call.ArgumentList) == 0 {
-			return prevObj.Value()
+			return prev.Value()
 		}
 		arg := call.Argument(0)
 		if isVertexChain(arg.Object()) {
-			return prevObj.Value()
+			return prev.Value()
 		}
 		newChain, _ := reverseGremlinChainTo(call.Otto, arg.Object(), "")
-		out.Set("_gremlin_prev", prevObj)
+		out.Set("_gremlin_prev", prev)
 		out.Set("_gremlin_followr", newChain)
-		embedTraversals(env, ses, out)
+		wk.embedTraversals(env, out)
 		if isVertexChain(call.This.Object()) {
-			embedFinals(env, ses, out)
+			wk.embedFinals(env, out)
 		}
 		return out.Value()
-
 	}
 }
 
-func reverseGremlinChainTo(env *otto.Otto, prevObj *otto.Object, tag string) (*otto.Object, *otto.Object) {
+func reverseGremlinChainTo(env *otto.Otto, prev *otto.Object, tag string) (*otto.Object, *otto.Object) {
 	env.Run("var _base_object = {}")
 	base, err := env.Object("_base_object")
 	if err != nil {
 		glog.Error(err)
 		return otto.NullValue().Object(), otto.NullValue().Object()
 	}
-	if isVertexChain(prevObj) {
+	if isVertexChain(prev) {
 		base.Set("_gremlin_type", "vertex")
 	} else {
 		base.Set("_gremlin_type", "morphism")
 	}
-	return reverseGremlinChainHelper(env, prevObj, base, tag)
+	return reverseGremlinChainHelper(env, prev, base, tag)
 }
 
 func reverseGremlinChainHelper(env *otto.Otto, chain *otto.Object, newBase *otto.Object, tag string) (*otto.Object, *otto.Object) {
 	kindVal, _ := chain.Get("_gremlin_type")
-	kind, _ := kindVal.ToString()
+	kind := kindVal.String()
 
 	if tag != "" {
 		if kind == "tag" {
-			tags := getStringArgs(chain)
+			tags := propertiesOf(chain, "string_args")
 			for _, t := range tags {
 				if t == tag {
 					return newBase, chain
@@ -174,8 +172,7 @@ func reverseGremlinChainHelper(env *otto.Otto, chain *otto.Object, newBase *otto
 
 func debugChain(obj *otto.Object) bool {
 	val, _ := obj.Get("_gremlin_type")
-	x, _ := val.ToString()
+	glog.V(2).Infoln(val)
-	glog.V(2).Infoln(x)
 	val, _ = obj.Get("_gremlin_prev")
 	if val.IsObject() {
 		return debugChain(val.Object())

query/mql/session.go

@@ -72,7 +72,7 @@ func (s *Session) InputParses(input string) (query.ParseResult, error) {
 	return query.Parsed, nil
 }
 
-func (s *Session) ExecInput(input string, c chan interface{}, limit int) {
+func (s *Session) ExecInput(input string, c chan interface{}, _ int) {
 	defer close(c)
 	var mqlQuery interface{}
 	err := json.Unmarshal([]byte(input), &mqlQuery)