303 lines
8.1 KiB
Go
303 lines
8.1 KiB
Go
// Copyright 2014 The Cayley Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package gremlin
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import (
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"strconv"
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"github.com/barakmich/glog"
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"github.com/robertkrimen/otto"
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"github.com/google/cayley/graph"
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"github.com/google/cayley/graph/iterator"
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"github.com/google/cayley/quad"
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)
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func propertiesOf(obj *otto.Object, name string) []string {
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val, _ := obj.Get(name)
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if val.IsUndefined() {
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return nil
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}
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export, _ := val.Export()
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return export.([]string)
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}
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func buildIteratorTree(obj *otto.Object, qs graph.QuadStore) graph.Iterator {
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if !isVertexChain(obj) {
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return iterator.NewNull()
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}
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return buildIteratorTreeHelper(obj, qs, iterator.NewNull())
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}
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func stringsFrom(obj *otto.Object) []string {
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var output []string
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lengthValue, _ := obj.Get("length")
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length, _ := lengthValue.ToInteger()
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ulength := uint32(length)
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for i := uint32(0); i < ulength; i++ {
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name := strconv.FormatInt(int64(i), 10)
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value, err := obj.Get(name)
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if err != nil || !value.IsString() {
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continue
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}
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output = append(output, value.String())
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}
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return output
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}
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func buildIteratorFromValue(val otto.Value, qs graph.QuadStore) graph.Iterator {
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if val.IsNull() || val.IsUndefined() {
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return qs.NodesAllIterator()
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}
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if val.IsPrimitive() {
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thing, _ := val.Export()
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switch v := thing.(type) {
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case string:
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it := qs.FixedIterator()
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it.Add(qs.ValueOf(v))
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return it
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default:
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glog.Errorln("Trying to build unknown primitive value.")
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}
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}
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switch val.Class() {
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case "Object":
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return buildIteratorTree(val.Object(), qs)
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case "Array":
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// Had better be an array of strings
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strings := stringsFrom(val.Object())
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it := qs.FixedIterator()
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for _, x := range strings {
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it.Add(qs.ValueOf(x))
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}
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return it
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case "Number":
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fallthrough
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case "Boolean":
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fallthrough
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case "Date":
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fallthrough
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case "String":
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it := qs.FixedIterator()
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it.Add(qs.ValueOf(val.String()))
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return it
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default:
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glog.Errorln("Trying to handle unsupported Javascript value.")
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return iterator.NewNull()
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}
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}
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func buildInOutIterator(obj *otto.Object, qs graph.QuadStore, base graph.Iterator, isReverse bool) graph.Iterator {
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argList, _ := obj.Get("_gremlin_values")
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if argList.Class() != "GoArray" {
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glog.Errorln("How is arglist not an array? Return nothing.", argList.Class())
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return iterator.NewNull()
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}
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argArray := argList.Object()
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lengthVal, _ := argArray.Get("length")
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length, _ := lengthVal.ToInteger()
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var predicateNodeIterator graph.Iterator
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if length == 0 {
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predicateNodeIterator = qs.NodesAllIterator()
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} else {
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zero, _ := argArray.Get("0")
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predicateNodeIterator = buildIteratorFromValue(zero, qs)
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}
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if length >= 2 {
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var tags []string
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one, _ := argArray.Get("1")
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if one.IsString() {
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tags = append(tags, one.String())
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} else if one.Class() == "Array" {
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tags = stringsFrom(one.Object())
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}
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for _, tag := range tags {
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predicateNodeIterator.Tagger().Add(tag)
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}
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}
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in, out := quad.Subject, quad.Object
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if isReverse {
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in, out = out, in
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}
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lto := iterator.NewLinksTo(qs, base, in)
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and := iterator.NewAnd()
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and.AddSubIterator(iterator.NewLinksTo(qs, predicateNodeIterator, quad.Predicate))
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and.AddSubIterator(lto)
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return iterator.NewHasA(qs, and, out)
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}
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func buildIteratorTreeHelper(obj *otto.Object, qs graph.QuadStore, base graph.Iterator) graph.Iterator {
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it := base
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// TODO: Better error handling
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var subIt graph.Iterator
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if prev, _ := obj.Get("_gremlin_prev"); !prev.IsObject() {
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subIt = base
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} else {
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subIt = buildIteratorTreeHelper(prev.Object(), qs, base)
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}
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stringArgs := propertiesOf(obj, "string_args")
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val, _ := obj.Get("_gremlin_type")
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switch val.String() {
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case "vertex":
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if len(stringArgs) == 0 {
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it = qs.NodesAllIterator()
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} else {
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fixed := qs.FixedIterator()
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for _, name := range stringArgs {
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fixed.Add(qs.ValueOf(name))
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}
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it = fixed
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}
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case "tag":
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it = subIt
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for _, tag := range stringArgs {
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it.Tagger().Add(tag)
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}
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case "save":
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all := qs.NodesAllIterator()
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if len(stringArgs) > 2 || len(stringArgs) == 0 {
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return iterator.NewNull()
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}
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if len(stringArgs) == 2 {
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all.Tagger().Add(stringArgs[1])
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} else {
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all.Tagger().Add(stringArgs[0])
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}
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predFixed := qs.FixedIterator()
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predFixed.Add(qs.ValueOf(stringArgs[0]))
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subAnd := iterator.NewAnd()
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Object))
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hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
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and := iterator.NewAnd()
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and.AddSubIterator(hasa)
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and.AddSubIterator(subIt)
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it = and
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case "saver":
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all := qs.NodesAllIterator()
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if len(stringArgs) > 2 || len(stringArgs) == 0 {
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return iterator.NewNull()
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}
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if len(stringArgs) == 2 {
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all.Tagger().Add(stringArgs[1])
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} else {
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all.Tagger().Add(stringArgs[0])
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}
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predFixed := qs.FixedIterator()
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predFixed.Add(qs.ValueOf(stringArgs[0]))
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subAnd := iterator.NewAnd()
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, all, quad.Subject))
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hasa := iterator.NewHasA(qs, subAnd, quad.Object)
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and := iterator.NewAnd()
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and.AddSubIterator(hasa)
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and.AddSubIterator(subIt)
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it = and
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case "has":
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fixed := qs.FixedIterator()
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if len(stringArgs) < 2 {
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return iterator.NewNull()
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}
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for _, name := range stringArgs[1:] {
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fixed.Add(qs.ValueOf(name))
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}
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predFixed := qs.FixedIterator()
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predFixed.Add(qs.ValueOf(stringArgs[0]))
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subAnd := iterator.NewAnd()
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, predFixed, quad.Predicate))
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subAnd.AddSubIterator(iterator.NewLinksTo(qs, fixed, quad.Object))
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hasa := iterator.NewHasA(qs, subAnd, quad.Subject)
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and := iterator.NewAnd()
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and.AddSubIterator(hasa)
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and.AddSubIterator(subIt)
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it = and
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case "morphism":
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it = base
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case "and":
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arg, _ := obj.Get("_gremlin_values")
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firstArg, _ := arg.Object().Get("0")
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if !isVertexChain(firstArg.Object()) {
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return iterator.NewNull()
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}
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argIt := buildIteratorTree(firstArg.Object(), qs)
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and := iterator.NewAnd()
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and.AddSubIterator(subIt)
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and.AddSubIterator(argIt)
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it = and
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case "back":
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arg, _ := obj.Get("_gremlin_back_chain")
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argIt := buildIteratorTree(arg.Object(), qs)
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and := iterator.NewAnd()
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and.AddSubIterator(subIt)
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and.AddSubIterator(argIt)
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it = and
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case "is":
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fixed := qs.FixedIterator()
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for _, name := range stringArgs {
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fixed.Add(qs.ValueOf(name))
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}
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and := iterator.NewAnd()
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and.AddSubIterator(fixed)
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and.AddSubIterator(subIt)
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it = and
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case "or":
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arg, _ := obj.Get("_gremlin_values")
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firstArg, _ := arg.Object().Get("0")
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if !isVertexChain(firstArg.Object()) {
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return iterator.NewNull()
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}
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argIt := buildIteratorTree(firstArg.Object(), qs)
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or := iterator.NewOr()
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or.AddSubIterator(subIt)
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or.AddSubIterator(argIt)
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it = or
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case "both":
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// Hardly the most efficient pattern, but the most general.
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// Worth looking into an Optimize() optimization here.
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clone := subIt.Clone()
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it1 := buildInOutIterator(obj, qs, subIt, false)
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it2 := buildInOutIterator(obj, qs, clone, true)
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or := iterator.NewOr()
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or.AddSubIterator(it1)
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or.AddSubIterator(it2)
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it = or
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case "out":
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it = buildInOutIterator(obj, qs, subIt, false)
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case "follow":
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// Follow a morphism
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arg, _ := obj.Get("_gremlin_values")
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firstArg, _ := arg.Object().Get("0")
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if isVertexChain(firstArg.Object()) {
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return iterator.NewNull()
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}
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it = buildIteratorTreeHelper(firstArg.Object(), qs, subIt)
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case "followr":
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// Follow a morphism
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arg, _ := obj.Get("_gremlin_followr")
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if isVertexChain(arg.Object()) {
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return iterator.NewNull()
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}
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it = buildIteratorTreeHelper(arg.Object(), qs, subIt)
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case "in":
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it = buildInOutIterator(obj, qs, subIt, true)
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}
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return it
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}
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