func NewGraph(euid uint64, exid string) (*SubGraph, error) {
// This would set the Result field in SubGraph,
// and populate the children for attributes.
if len(exid) > 0 {
u, err := uid.GetOrAssign(exid)
if err != nil {
x.Err(glog, err).WithField("xid", exid).Error(
"While GetOrAssign uid from external id")
return nil, err
}
glog.WithField("xid", exid).WithField("_uid_", u).Debug("GetOrAssign")
euid = u
}
if euid == 0 {
err := fmt.Errorf("Query internal id is zero")
x.Err(glog, err).Error("Invalid query")
return nil, err
}
// Encode uid into result flatbuffer.
b := flatbuffers.NewBuilder(0)
omatrix := x.UidlistOffset(b, []uint64{euid})
// Also need to add nil value to keep this consistent.
var voffset flatbuffers.UOffsetT
{
bvo := b.CreateByteVector(x.Nilbyte)
task.ValueStart(b)
task.ValueAddVal(b, bvo)
voffset = task.ValueEnd(b)
}
task.ResultStartUidmatrixVector(b, 1)
b.PrependUOffsetT(omatrix)
mend := b.EndVector(1)
task.ResultStartValuesVector(b, 1)
b.PrependUOffsetT(voffset)
vend := b.EndVector(1)
task.ResultStart(b)
task.ResultAddUidmatrix(b, mend)
task.ResultAddValues(b, vend)
rend := task.ResultEnd(b)
b.Finish(rend)
sg := new(SubGraph)
sg.Attr = "_root_"
sg.result = b.Bytes[b.Head():]
// Also add query for consistency and to allow for ToJson() later.
sg.query = createTaskQuery(sg.Attr, []uint64{euid})
return sg, nil
}
func ProcessTask(query []byte) (result []byte, rerr error) {
uo := flatbuffers.GetUOffsetT(query)
q := new(task.Query)
q.Init(query, uo)
b := flatbuffers.NewBuilder(0)
voffsets := make([]flatbuffers.UOffsetT, q.UidsLength())
uoffsets := make([]flatbuffers.UOffsetT, q.UidsLength())
attr := string(q.Attr())
for i := 0; i < q.UidsLength(); i++ {
uid := q.Uids(i)
key := posting.Key(uid, attr)
pl := posting.GetOrCreate(key, dataStore)
var valoffset flatbuffers.UOffsetT
if val, err := pl.Value(); err != nil {
valoffset = b.CreateByteVector(x.Nilbyte)
} else {
valoffset = b.CreateByteVector(val)
}
task.ValueStart(b)
task.ValueAddVal(b, valoffset)
voffsets[i] = task.ValueEnd(b)
ulist := pl.GetUids()
uoffsets[i] = x.UidlistOffset(b, ulist)
}
task.ResultStartValuesVector(b, len(voffsets))
for i := len(voffsets) - 1; i >= 0; i-- {
b.PrependUOffsetT(voffsets[i])
}
valuesVent := b.EndVector(len(voffsets))
task.ResultStartUidmatrixVector(b, len(uoffsets))
for i := len(uoffsets) - 1; i >= 0; i-- {
b.PrependUOffsetT(uoffsets[i])
}
matrixVent := b.EndVector(len(uoffsets))
task.ResultStart(b)
task.ResultAddValues(b, valuesVent)
task.ResultAddUidmatrix(b, matrixVent)
rend := task.ResultEnd(b)
b.Finish(rend)
return b.Bytes[b.Head():], nil
}