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()
and.AddSubIterator(subIt)
and.AddSubIterator(argIt)
it = and
case "back":
arg, _ := obj.Get("_gremlin_back_chain")
argIt := buildIteratorTree(arg.Object(), ts)
and := graph.NewAndIterator()
and.AddSubIterator(subIt)
and.AddSubIterator(argIt)
it = and
case "is":
fixed := ts.MakeFixed()
for _, name := range stringArgs {
fixed.AddValue(ts.GetIdFor(name))
}
and := graph.NewAndIterator()
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 graph.NewNullIterator()
}
argIt := buildIteratorTree(firstArg.Object(), ts)
or := graph.NewOrIterator()
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, ts, subIt, false)
it2 := buildInOutIterator(obj, ts, clone, true)
or := graph.NewOrIterator()
or.AddSubIterator(it1)
or.AddSubIterator(it2)
it = or
case "out":
it = buildInOutIterator(obj, ts, subIt, false)
case "follow":
// Follow a morphism
arg, _ := obj.Get("_gremlin_values")
firstArg, _ := arg.Object().Get("0")
if isVertexChain(firstArg.Object()) {
return graph.NewNullIterator()
}
it = buildIteratorTreeHelper(firstArg.Object(), ts, subIt)
case "followr":
// Follow a morphism
arg, _ := obj.Get("_gremlin_followr")
if isVertexChain(arg.Object()) {
return graph.NewNullIterator()
}
it = buildIteratorTreeHelper(arg.Object(), ts, subIt)
case "in":
it = buildInOutIterator(obj, ts, subIt, true)
}
return it
}
func buildIteratorTree(tree *peg.ExpressionTree, ts graph.TripleStore) graph.Iterator {
switch tree.Name {
case "Start":
return buildIteratorTree(tree.Children[0], ts)
case "NodeIdentifier":
var out graph.Iterator
nodeID := getIdentString(tree)
if tree.Children[0].Name == "Variable" {
allIt := ts.GetNodesAllIterator()
allIt.AddTag(nodeID)
out = allIt
} else {
n := nodeID
if tree.Children[0].Children[0].Name == "ColonIdentifier" {
n = nodeID[1:]
}
fixed := ts.MakeFixed()
fixed.AddValue(ts.GetIdFor(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], ts)
lto := graph.NewLinksToIterator(ts, it, "p")
return lto
case "RootConstraint":
constraintCount := 0
and := graph.NewAndIterator()
for _, c := range tree.Children {
switch c.Name {
case "NodeIdentifier":
fallthrough
case "Constraint":
it := buildIteratorTree(c, ts)
and.AddSubIterator(it)
constraintCount++
continue
default:
continue
}
}
return and
case "Constraint":
var hasa *graph.HasaIterator
topLevelDir := "s"
subItDir := "o"
subAnd := graph.NewAndIterator()
isOptional := false
for _, c := range tree.Children {
switch c.Name {
case "PredIdentifier":
if c.Children[0].Name == "Reverse" {
topLevelDir = "o"
subItDir = "s"
}
it := buildIteratorTree(c, ts)
subAnd.AddSubIterator(it)
continue
case "PredicateKeyword":
switch c.Children[0].Name {
case "OptionalKeyword":
isOptional = true
}
case "NodeIdentifier":
fallthrough
case "RootConstraint":
it := buildIteratorTree(c, ts)
l := graph.NewLinksToIterator(ts, it, subItDir)
subAnd.AddSubIterator(l)
continue
default:
continue
}
}
hasa = graph.NewHasaIterator(ts, subAnd, topLevelDir)
if isOptional {
optional := graph.NewOptionalIterator(hasa)
return optional
}
return hasa
default:
return &graph.NullIterator{}
}
panic("Not reached")
}