Rewrite Gremlin's buildIterator in terms of paths

This commit is contained in:
Barak Michener 2015-10-28 21:26:29 -04:00
parent 97247ae40f
commit f74051a520
5 changed files with 246 additions and 391 deletions

View file

@ -15,6 +15,8 @@
package path
import (
"fmt"
"github.com/google/cayley/graph"
"github.com/google/cayley/graph/iterator"
"github.com/google/cayley/quad"
@ -114,25 +116,41 @@ func tagMorphism(tags ...string) morphism {
}
// outMorphism iterates forward one RDF triple or via an entire path.
func outMorphism(via ...interface{}) morphism {
func outMorphism(tags []string, via ...interface{}) morphism {
return morphism{
Name: "out",
Reversal: func() morphism { return inMorphism(via...) },
Reversal: func() morphism { return inMorphism(tags, via...) },
Apply: func(qs graph.QuadStore, in graph.Iterator, ctx *context) (graph.Iterator, *context) {
path := buildViaPath(qs, via...)
return inOutIterator(path, in, false), ctx
return inOutIterator(path, in, false, tags), ctx
},
}
}
// inMorphism iterates backwards one RDF triple or via an entire path.
func inMorphism(via ...interface{}) morphism {
func inMorphism(tags []string, via ...interface{}) morphism {
return morphism{
Name: "in",
Reversal: func() morphism { return outMorphism(via...) },
Reversal: func() morphism { return outMorphism(tags, via...) },
Apply: func(qs graph.QuadStore, in graph.Iterator, ctx *context) (graph.Iterator, *context) {
path := buildViaPath(qs, via...)
return inOutIterator(path, in, true), ctx
return inOutIterator(path, in, true, tags), ctx
},
}
}
func bothMorphism(tags []string, via ...interface{}) morphism {
return morphism{
Name: "in",
Reversal: func() morphism { return bothMorphism(tags, via...) },
Apply: func(qs graph.QuadStore, in graph.Iterator, ctx *context) (graph.Iterator, *context) {
path := buildViaPath(qs, via...)
inSide := inOutIterator(path, in, true, tags)
outSide := inOutIterator(path, in.Clone(), false, tags)
or := iterator.NewOr()
or.AddSubIterator(inSide)
or.AddSubIterator(outSide)
return or, ctx
},
}
}
@ -270,13 +288,16 @@ func buildSave(
return join(qs, from, save)
}
func inOutIterator(viaPath *Path, from graph.Iterator, inIterator bool) graph.Iterator {
func inOutIterator(viaPath *Path, from graph.Iterator, inIterator bool, tags []string) graph.Iterator {
start, goal := quad.Subject, quad.Object
if inIterator {
start, goal = goal, start
}
viaIter := viaPath.BuildIterator()
for _, tag := range tags {
viaIter.Tagger().Add(tag)
}
source := iterator.NewLinksTo(viaPath.qs, from, start)
trail := iterator.NewLinksTo(viaPath.qs, viaIter, quad.Predicate)
@ -292,12 +313,22 @@ func buildViaPath(qs graph.QuadStore, via ...interface{}) *Path {
} else if len(via) == 1 {
v := via[0]
switch p := v.(type) {
case nil:
return PathFromIterator(qs, qs.NodesAllIterator())
case *Path:
if p.qs != qs {
newp := &Path{
qs: qs,
baseContext: p.baseContext,
stack: p.stack[:],
}
return newp
}
return p
case string:
return StartPath(qs, p)
default:
panic("Invalid type passed to buildViaPath.")
panic(fmt.Sprint("Invalid type passed to buildViaPath. ", p))
}
}
var strings []string

View file

@ -14,11 +14,7 @@
package path
import (
"fmt"
"github.com/google/cayley/graph"
)
import "github.com/google/cayley/graph"
type applyMorphism func(graph.QuadStore, graph.Iterator, *context) (graph.Iterator, *context)
@ -102,13 +98,13 @@ func (p *Path) Tag(tags ...string) *Path {
// current nodes, via the given outbound predicate.
//
// For example:
// // Returns the list of nodes that "A" follows.
// // Returns the list of nodes that "B" follows.
// //
// // Will return []string{"B"} if there is a predicate (edge) from "A"
// // to "B" labelled "follows".
// // Will return []string{"F"} if there is a predicate (edge) from "B"
// // to "F" labelled "follows".
// StartPath(qs, "A").Out("follows")
func (p *Path) Out(via ...interface{}) *Path {
p.stack = append(p.stack, outMorphism(via...))
p.stack = append(p.stack, outMorphism(nil, via...))
return p
}
@ -122,7 +118,34 @@ func (p *Path) Out(via ...interface{}) *Path {
// // edges from those nodes to "B" labelled "follows".
// StartPath(qs, "B").In("follows")
func (p *Path) In(via ...interface{}) *Path {
p.stack = append(p.stack, inMorphism(via...))
p.stack = append(p.stack, inMorphism(nil, via...))
return p
}
// InWithTags is exactly like In, except it tags the value of the predicate
// traversed with the tags provided.
func (p *Path) InWithTags(tags []string, via ...interface{}) *Path {
p.stack = append(p.stack, inMorphism(tags, via...))
return p
}
// OutWithTags is exactly like In, except it tags the value of the predicate
// traversed with the tags provided.
func (p *Path) OutWithTags(tags []string, via ...interface{}) *Path {
p.stack = append(p.stack, outMorphism(tags, via...))
return p
}
// Both updates this path following both inbound and outbound predicates.
//
// For example:
// // Return the list of nodes that follow or are followed by "B".
// //
// // Will return []string{"A", "C", "D", "F} if there are the appropriate
// // edges from those nodes to "B" labelled "follows", in either direction.
// StartPath(qs, "B").Both("follows")
func (p *Path) Both(via ...interface{}) *Path {
p.stack = append(p.stack, bothMorphism(nil, via...))
return p
}
@ -275,12 +298,3 @@ func (p *Path) Morphism() graph.ApplyMorphism {
return i
}
}
func (p *Path) debugPrint() {
var strs []string
for _, x := range p.stack {
strs = append(strs, x.Name)
}
fmt.Println("stack:", strs)
fmt.Println("ctx:", p.baseContext)
}

View file

@ -15,6 +15,7 @@
package gremlin
import (
"fmt"
"strconv"
"github.com/barakmich/glog"
@ -22,7 +23,7 @@ import (
"github.com/google/cayley/graph"
"github.com/google/cayley/graph/iterator"
"github.com/google/cayley/quad"
"github.com/google/cayley/graph/path"
)
func propertiesOf(obj *otto.Object, name string) []string {
@ -38,7 +39,133 @@ func buildIteratorTree(obj *otto.Object, qs graph.QuadStore) graph.Iterator {
if !isVertexChain(obj) {
return iterator.NewNull()
}
return buildIteratorTreeHelper(obj, qs, iterator.NewNull())
path := buildPathFromObject(obj)
if path == nil {
return iterator.NewNull()
}
return path.BuildIteratorOn(qs)
}
func getFirstArgAsVertexChain(obj *otto.Object) *otto.Object {
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if !isVertexChain(firstArg.Object()) {
return nil
}
return firstArg.Object()
}
func getFirstArgAsMorphismChain(obj *otto.Object) *otto.Object {
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if isVertexChain(firstArg.Object()) {
return nil
}
return firstArg.Object()
}
func buildPathFromObject(obj *otto.Object) *path.Path {
var p *path.Path
val, _ := obj.Get("_gremlin_type")
stringArgs := propertiesOf(obj, "string_args")
gremlinType := val.String()
if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
switch gremlinType {
case "vertex":
return path.StartMorphism(stringArgs...)
case "morphism":
return path.StartMorphism()
default:
panic("No base gremlin path other than 'vertex' or 'morphism'")
}
} else {
p = buildPathFromObject(prev.Object())
}
if p == nil {
return nil
}
switch gremlinType {
case "Is":
return p.Is(stringArgs...)
case "In":
preds, tags, ok := getViaData(obj)
if !ok {
return nil
}
return p.InWithTags(tags, preds...)
case "Out":
preds, tags, ok := getViaData(obj)
if !ok {
return nil
}
return p.OutWithTags(tags, preds...)
case "Both":
preds, _, ok := getViaData(obj)
if !ok {
return nil
}
return p.Both(preds...)
case "Follow":
subobj := getFirstArgAsMorphismChain(obj)
if subobj == nil {
return nil
}
return p.Follow(buildPathFromObject(subobj))
case "FollowR":
subobj := getFirstArgAsMorphismChain(obj)
if subobj == nil {
return nil
}
return p.FollowReverse(buildPathFromObject(subobj))
case "And", "Intersect":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.And(buildPathFromObject(subobj))
case "Union", "Or":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.And(buildPathFromObject(subobj))
case "Back":
if len(stringArgs) != 1 {
return nil
}
return p.Back(stringArgs[0])
case "Tag", "As":
return p.Tag(stringArgs...)
case "Has":
if len(stringArgs) < 2 {
return nil
}
return p.Has(stringArgs[0], stringArgs[1:]...)
case "Save", "SaveR":
if len(stringArgs) > 2 || len(stringArgs) == 0 {
return nil
}
tag := stringArgs[0]
if len(stringArgs) == 2 {
tag = stringArgs[1]
}
if gremlinType == "SaveR" {
return p.SaveReverse(stringArgs[0], tag)
}
return p.Save(stringArgs[0], tag)
case "Except", "Difference":
subobj := getFirstArgAsVertexChain(obj)
if subobj == nil {
return nil
}
return p.Except(buildPathFromObject(subobj))
case "InPredicates":
return p.InPredicates()
case "OutPredicates":
return p.OutPredicates()
default:
panic(fmt.Sprint("Unimplemented Gremlin function", gremlinType))
}
}
func stringsFrom(obj *otto.Object) []string {
@ -57,32 +184,30 @@ func stringsFrom(obj *otto.Object) []string {
return output
}
func buildIteratorFromValue(val otto.Value, qs graph.QuadStore) graph.Iterator {
func buildPathFromValue(val otto.Value) (out []interface{}) {
if val.IsNull() || val.IsUndefined() {
return qs.NodesAllIterator()
return nil
}
if val.IsPrimitive() {
thing, _ := val.Export()
switch v := thing.(type) {
case string:
it := qs.FixedIterator()
it.Add(qs.ValueOf(v))
return it
out = append(out, v)
return
default:
glog.Errorln("Trying to build unknown primitive value.")
}
}
switch val.Class() {
case "Object":
return buildIteratorTree(val.Object(), qs)
out = append(out, buildPathFromObject(val.Object()))
return
case "Array":
// Had better be an array of strings
strings := stringsFrom(val.Object())
it := qs.FixedIterator()
for _, x := range strings {
it.Add(qs.ValueOf(x))
for _, x := range stringsFrom(val.Object()) {
out = append(out, x)
}
return it
return
case "Number":
fallthrough
case "Boolean":
@ -90,248 +215,37 @@ func buildIteratorFromValue(val otto.Value, qs graph.QuadStore) graph.Iterator {
case "Date":
fallthrough
case "String":
it := qs.FixedIterator()
it.Add(qs.ValueOf(val.String()))
return it
out = append(out, val.String())
return
default:
glog.Errorln("Trying to handle unsupported Javascript value.")
return iterator.NewNull()
return nil
}
}
func buildInOutIterator(obj *otto.Object, qs graph.QuadStore, base graph.Iterator, isReverse bool) graph.Iterator {
func getViaData(obj *otto.Object) (predicates []interface{}, tags []string, ok bool) {
argList, _ := obj.Get("_gremlin_values")
if argList.Class() != "GoArray" {
glog.Errorln("How is arglist not an array? Return nothing.", argList.Class())
return iterator.NewNull()
return nil, nil, false
}
argArray := argList.Object()
lengthVal, _ := argArray.Get("length")
length, _ := lengthVal.ToInteger()
var predicateNodeIterator graph.Iterator
if length == 0 {
predicateNodeIterator = qs.NodesAllIterator()
predicates = []interface{}{}
} else {
zero, _ := argArray.Get("0")
predicateNodeIterator = buildIteratorFromValue(zero, qs)
predicates = buildPathFromValue(zero)
}
if length >= 2 {
var tags []string
one, _ := argArray.Get("1")
if one.IsString() {
tags = append(tags, one.String())
} else if one.Class() == "Array" {
tags = stringsFrom(one.Object())
}
for _, tag := range tags {
predicateNodeIterator.Tagger().Add(tag)
}
}
in, out := quad.Subject, quad.Object
if isReverse {
in, out = out, in
}
lto := iterator.NewLinksTo(qs, base, in)
and := iterator.NewAnd(qs)
and.AddSubIterator(iterator.NewLinksTo(qs, predicateNodeIterator, quad.Predicate))
and.AddSubIterator(lto)
return iterator.NewHasA(qs, and, out)
}
func buildInOutPredicateIterator(obj *otto.Object, qs graph.QuadStore, base graph.Iterator, isReverse bool) graph.Iterator {
dir := quad.Subject
if isReverse {
dir = quad.Object
}
lto := iterator.NewLinksTo(qs, base, dir)
hasa := iterator.NewHasA(qs, lto, quad.Predicate)
return iterator.NewUnique(hasa)
}
func buildIteratorTreeHelper(obj *otto.Object, qs graph.QuadStore, base graph.Iterator) graph.Iterator {
// TODO: Better error handling
var (
it graph.Iterator
subIt graph.Iterator
)
if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
subIt = base
} else {
subIt = buildIteratorTreeHelper(prev.Object(), qs, base)
}
stringArgs := propertiesOf(obj, "string_args")
val, _ := obj.Get("_gremlin_type")
switch val.String() {
case "vertex":
if len(stringArgs) == 0 {
it = qs.NodesAllIterator()
} else {
fixed := qs.FixedIterator()
for _, name := range stringArgs {
fixed.Add(qs.ValueOf(name))
}
it = fixed
}
case "tag":
it = subIt
for _, tag := range stringArgs {
it.Tagger().Add(tag)
}
case "save":
all := qs.NodesAllIterator()
if len(stringArgs) > 2 || len(stringArgs) == 0 {
return iterator.NewNull()
}
if len(stringArgs) == 2 {
all.Tagger().Add(stringArgs[1])
} else {
all.Tagger().Add(stringArgs[0])
}
predFixed := qs.FixedIterator()
predFixed.Add(qs.ValueOf(stringArgs[0]))
subAnd := iterator.NewAnd(qs)
subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Object))
hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
and := iterator.NewAnd(qs)
and.AddSubIterator(hasa)
and.AddSubIterator(subIt)
it = and
case "saver":
all := qs.NodesAllIterator()
if len(stringArgs) > 2 || len(stringArgs) == 0 {
return iterator.NewNull()
}
if len(stringArgs) == 2 {
all.Tagger().Add(stringArgs[1])
} else {
all.Tagger().Add(stringArgs[0])
}
predFixed := qs.FixedIterator()
predFixed.Add(qs.ValueOf(stringArgs[0]))
subAnd := iterator.NewAnd(qs)
subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Subject))
hasa := iterator.NewHasA(qs, subAnd, quad.Object)
and := iterator.NewAnd(qs)
and.AddSubIterator(hasa)
and.AddSubIterator(subIt)
it = and
case "has":
fixed := qs.FixedIterator()
if len(stringArgs) < 2 {
return iterator.NewNull()
}
for _, name := range stringArgs[1:] {
fixed.Add(qs.ValueOf(name))
}
predFixed := qs.FixedIterator()
predFixed.Add(qs.ValueOf(stringArgs[0]))
subAnd := iterator.NewAnd(qs)
subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
subAnd.AddSubIterator(iterator.NewLinksTo(qs, fixed, quad.Object))
hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
and := iterator.NewAnd(qs)
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 iterator.NewNull()
}
argIt := buildIteratorTree(firstArg.Object(), qs)
and := iterator.NewAnd(qs)
and.AddSubIterator(subIt)
and.AddSubIterator(argIt)
it = and
case "back":
arg, _ := obj.Get("_gremlin_back_chain")
argIt := buildIteratorTree(arg.Object(), qs)
and := iterator.NewAnd(qs)
and.AddSubIterator(subIt)
and.AddSubIterator(argIt)
it = and
case "is":
fixed := qs.FixedIterator()
for _, name := range stringArgs {
fixed.Add(qs.ValueOf(name))
}
and := iterator.NewAnd(qs)
and.AddSubIterator(fixed)
and.AddSubIterator(subIt)
it = and
case "or":
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if !isVertexChain(firstArg.Object()) {
return iterator.NewNull()
}
argIt := buildIteratorTree(firstArg.Object(), qs)
or := iterator.NewOr()
or.AddSubIterator(subIt)
or.AddSubIterator(argIt)
it = or
case "both":
// Hardly the most efficient pattern, but the most general.
// Worth looking into an Optimize() optimization here.
clone := subIt.Clone()
it1 := buildInOutIterator(obj, qs, subIt, false)
it2 := buildInOutIterator(obj, qs, clone, true)
or := iterator.NewOr()
or.AddSubIterator(it1)
or.AddSubIterator(it2)
it = or
case "out":
it = buildInOutIterator(obj, qs, subIt, false)
case "follow":
// Follow a morphism
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if isVertexChain(firstArg.Object()) {
return iterator.NewNull()
}
it = buildIteratorTreeHelper(firstArg.Object(), qs, subIt)
case "followr":
// Follow a morphism
arg, _ := obj.Get("_gremlin_followr")
if isVertexChain(arg.Object()) {
return iterator.NewNull()
}
it = buildIteratorTreeHelper(arg.Object(), qs, subIt)
case "in":
it = buildInOutIterator(obj, qs, subIt, true)
case "except":
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if !isVertexChain(firstArg.Object()) {
return iterator.NewNull()
}
allIt := qs.NodesAllIterator()
toComplementIt := buildIteratorTree(firstArg.Object(), qs)
notIt := iterator.NewNot(toComplementIt, allIt)
and := iterator.NewAnd(qs)
and.AddSubIterator(subIt)
and.AddSubIterator(notIt)
it = and
case "in_predicates":
it = buildInOutPredicateIterator(obj, qs, subIt, true)
case "out_predicates":
it = buildInOutPredicateIterator(obj, qs, subIt, false)
}
if it == nil {
panic("Iterator building does not catch the output iterator in some case.")
}
return it
ok = true
return
}

View file

@ -322,6 +322,7 @@ func TestGremlin(t *testing.T) {
got := runQueryGetTag(simpleGraph, test.query, test.tag)
sort.Strings(got)
sort.Strings(test.expect)
t.Log("testing", test.message)
if !reflect.DeepEqual(got, test.expect) {
t.Errorf("Failed to %s, got: %v expected: %v", test.message, got, test.expect)
}

View file

@ -21,27 +21,33 @@ import (
"github.com/robertkrimen/otto"
)
var traversals = []string{
"In",
"Out",
"Is",
"Both",
"Follow",
"FollowR",
"And",
"Intersect",
"Union",
"Or",
"Back",
"Tag",
"As",
"Has",
"Save",
"SaveR",
"Except",
"Difference",
"InPredicates",
"OutPredicates",
}
func (wk *worker) embedTraversals(env *otto.Otto, obj *otto.Object) {
obj.Set("In", wk.gremlinFunc("in", obj, env))
obj.Set("Out", wk.gremlinFunc("out", obj, env))
obj.Set("Is", wk.gremlinFunc("is", obj, env))
obj.Set("Both", wk.gremlinFunc("both", obj, env))
obj.Set("Follow", wk.gremlinFunc("follow", obj, env))
obj.Set("FollowR", wk.gremlinFollowR("followr", obj, env))
obj.Set("And", wk.gremlinFunc("and", obj, env))
obj.Set("Intersect", wk.gremlinFunc("and", obj, env))
obj.Set("Union", wk.gremlinFunc("or", obj, env))
obj.Set("Or", wk.gremlinFunc("or", obj, env))
obj.Set("Back", wk.gremlinBack("back", obj, env))
obj.Set("Tag", wk.gremlinFunc("tag", obj, env))
obj.Set("As", wk.gremlinFunc("tag", obj, env))
obj.Set("Has", wk.gremlinFunc("has", obj, env))
obj.Set("Save", wk.gremlinFunc("save", obj, env))
obj.Set("SaveR", wk.gremlinFunc("saver", obj, env))
obj.Set("Except", wk.gremlinFunc("except", obj, env))
obj.Set("Difference", wk.gremlinFunc("except", obj, env))
obj.Set("InPredicates", wk.gremlinFunc("in_predicates", obj, env))
obj.Set("OutPredicates", wk.gremlinFunc("out_predicates", obj, env))
for _, t := range traversals {
obj.Set(t, wk.gremlinFunc(t, obj, env))
}
}
func (wk *worker) gremlinFunc(kind string, prev *otto.Object, env *otto.Otto) func(otto.FunctionCall) otto.Value {
@ -63,117 +69,6 @@ func (wk *worker) gremlinFunc(kind string, prev *otto.Object, env *otto.Otto) fu
}
}
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)
args := argsOf(call)
if len(args) > 0 {
out.Set("string_args", args)
}
var otherChain *otto.Object
var thisObj *otto.Object
if len(args) != 0 {
otherChain, thisObj = reverseGremlinChainTo(call.Otto, prev, args[0])
} else {
otherChain, thisObj = reverseGremlinChainTo(call.Otto, prev, "")
}
out.Set("_gremlin_prev", thisObj)
out.Set("_gremlin_back_chain", otherChain)
wk.embedTraversals(env, out)
if isVertexChain(call.This.Object()) {
wk.embedFinals(env, out)
}
return out.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)
args := argsOf(call)
if len(args) > 0 {
out.Set("string_args", args)
}
if len(call.ArgumentList) == 0 {
return prev.Value()
}
arg := call.Argument(0)
if isVertexChain(arg.Object()) {
return prev.Value()
}
newChain, _ := reverseGremlinChainTo(call.Otto, arg.Object(), "")
out.Set("_gremlin_prev", prev)
out.Set("_gremlin_followr", newChain)
wk.embedTraversals(env, out)
if isVertexChain(call.This.Object()) {
wk.embedFinals(env, out)
}
return out.Value()
}
}
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(prev) {
base.Set("_gremlin_type", "vertex")
} else {
base.Set("_gremlin_type", "morphism")
}
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.String()
if tag != "" {
if kind == "tag" {
tags := propertiesOf(chain, "string_args")
for _, t := range tags {
if t == tag {
return newBase, chain
}
}
}
}
if kind == "morphism" || kind == "vertex" {
return newBase, chain
}
var newKind string
switch kind {
case "in":
newKind = "out"
case "out":
newKind = "in"
default:
newKind = kind
}
prev, _ := chain.Get("_gremlin_prev")
env.Run("var out = {}")
out, _ := env.Object("out")
out.Set("_gremlin_type", newKind)
values, _ := chain.Get("_gremlin_values")
out.Set("_gremlin_values", values)
back, _ := chain.Get("_gremlin_back_chain")
out.Set("_gremlin_back_chain", back)
out.Set("_gremlin_prev", newBase)
strings, _ := chain.Get("string_args")
out.Set("string_args", strings)
return reverseGremlinChainHelper(env, prev.Object(), out, tag)
}
func debugChain(obj *otto.Object) bool {
val, _ := obj.Get("_gremlin_type")
glog.V(2).Infoln(val)