func buildIteratorFromValue(val otto.Value, qs graph.QuadStore) graph.Iterator {
if val.IsNull() || val.IsUndefined() {
return qs.NodesAllIterator()
}
if val.IsPrimitive() {
thing, _ := val.Export()
switch v := thing.(type) {
case string:
it := qs.FixedIterator()
it.Add(qs.ValueOf(v))
return it
default:
glog.Errorln("Trying to build unknown primitive value.")
}
}
switch val.Class() {
case "Object":
return buildIteratorTree(val.Object(), qs)
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))
}
return it
case "Number":
fallthrough
case "Boolean":
fallthrough
case "Date":
fallthrough
case "String":
it := qs.FixedIterator()
it.Add(qs.ValueOf(val.String()))
return it
default:
glog.Errorln("Trying to handle unsupported Javascript value.")
return iterator.NewNull()
}
}
func buildInOutIterator(obj *otto.Object, qs graph.QuadStore, 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 iterator.NewNull()
}
argArray := argList.Object()
lengthVal, _ := argArray.Get("length")
length, _ := lengthVal.ToInteger()
var predicateNodeIterator graph.Iterator
if length == 0 {
predicateNodeIterator = qs.NodesAllIterator()
} else {
zero, _ := argArray.Get("0")
predicateNodeIterator = buildIteratorFromValue(zero, qs)
}
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 buildSave(qs graph.QuadStore, via interface{}, tag string, it graph.Iterator, reverse bool) graph.Iterator {
all := qs.NodesAllIterator()
all.Tagger().Add(tag)
node, allDir := quad.Subject, quad.Object
var viaPath *Path
if via != nil {
viaPath = buildViaPath(qs, via)
} else {
viaPath = buildViaPath(qs)
}
if reverse {
node, allDir = allDir, node
}
lto := iterator.NewLinksTo(qs, all, allDir)
subAnd := iterator.NewAnd(qs)
subAnd.AddSubIterator(iterator.NewLinksTo(qs, viaPath.BuildIterator(), quad.Predicate))
subAnd.AddSubIterator(lto)
hasa := iterator.NewHasA(qs, subAnd, node)
and := iterator.NewAnd(qs)
and.AddSubIterator(hasa)
and.AddSubIterator(it)
return and
}
func buildViaPath(qs graph.QuadStore, via ...interface{}) *Path {
if len(via) == 0 {
return PathFromIterator(qs, qs.NodesAllIterator())
} else if len(via) == 1 {
v := via[0]
switch p := v.(type) {
case *Path:
return p
case string:
return StartPath(qs, p)
default:
panic("Invalid type passed to buildViaPath.")
}
}
var strings []string
for _, s := range via {
if str, ok := s.(string); ok {
strings = append(strings, str)
} else {
panic("Non-string type passed to long Via path")
}
}
return StartPath(qs, strings...)
}
// BuildIteratorOn will return an iterator for this path on the given QuadStore.
func (p *Path) BuildIteratorOn(qs graph.QuadStore) graph.Iterator {
return p.Morphism()(qs, qs.NodesAllIterator())
}
func buildIteratorTree(tree *peg.ExpressionTree, qs graph.QuadStore) graph.Iterator {
switch tree.Name {
case "Start":
return buildIteratorTree(tree.Children[0], qs)
case "NodeIdentifier":
var out graph.Iterator
nodeID := getIdentString(tree)
if tree.Children[0].Name == "Variable" {
allIt := qs.NodesAllIterator()
allIt.Tagger().Add(nodeID)
out = allIt
} else {
n := nodeID
if tree.Children[0].Children[0].Name == "ColonIdentifier" {
n = nodeID[1:]
}
fixed := qs.FixedIterator()
fixed.Add(qs.ValueOf(n))
out = fixed
}
return out
case "PredIdentifier":
i := 0
if tree.Children[0].Name == "Reverse" {
//Taken care of below
i++
}
it := buildIteratorTree(tree.Children[i], qs)
lto := iterator.NewLinksTo(qs, it, quad.Predicate)
return lto
case "RootConstraint":
constraintCount := 0
and := iterator.NewAnd(qs)
for _, c := range tree.Children {
switch c.Name {
case "NodeIdentifier":
fallthrough
case "Constraint":
it := buildIteratorTree(c, qs)
and.AddSubIterator(it)
constraintCount++
continue
default:
continue
}
}
return and
case "Constraint":
var hasa *iterator.HasA
topLevelDir := quad.Subject
subItDir := quad.Object
subAnd := iterator.NewAnd(qs)
isOptional := false
for _, c := range tree.Children {
switch c.Name {
case "PredIdentifier":
if c.Children[0].Name == "Reverse" {
topLevelDir = quad.Object
subItDir = quad.Subject
}
it := buildIteratorTree(c, qs)
subAnd.AddSubIterator(it)
continue
case "PredicateKeyword":
switch c.Children[0].Name {
case "OptionalKeyword":
isOptional = true
}
case "NodeIdentifier":
fallthrough
case "RootConstraint":
it := buildIteratorTree(c, qs)
l := iterator.NewLinksTo(qs, it, subItDir)
subAnd.AddSubIterator(l)
continue
default:
continue
}
}
hasa = iterator.NewHasA(qs, subAnd, topLevelDir)
if isOptional {
optional := iterator.NewOptional(hasa)
return optional
}
return hasa
default:
return &iterator.Null{}
}
}
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
}