// Next advances the Or graph.iterator. Because the Or is the union of its
// subiterators, it must produce from all subiterators -- unless it it
// shortcircuiting, in which case, it is the first one that returns anything.
func (it *Or) Next() bool {
graph.NextLogIn(it)
var first bool
for {
if it.currentIterator == -1 {
it.currentIterator = 0
first = true
}
curIt := it.internalIterators[it.currentIterator]
if graph.Next(curIt) {
it.result = curIt.Result()
return graph.NextLogOut(it, it.result, true)
}
it.err = curIt.Err()
if it.err != nil {
return graph.NextLogOut(it, nil, false)
}
if it.isShortCircuiting && !first {
break
}
it.currentIterator++
if it.currentIterator == it.itCount {
break
}
}
return graph.NextLogOut(it, nil, false)
}
// Next()ing a LinksTo operates as described above.
func (it *LinksTo) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
if graph.Next(it.nextIt) {
it.runstats.ContainsNext += 1
it.result = it.nextIt.Result()
return graph.NextLogOut(it, it.nextIt, true)
}
// If there's an error in the 'next' iterator, we save it and we're done.
it.err = it.nextIt.Err()
if it.err != nil {
return false
}
// Subiterator is empty, get another one
if !graph.Next(it.primaryIt) {
// Possibly save error
it.err = it.primaryIt.Err()
// We're out of nodes in our subiterator, so we're done as well.
return graph.NextLogOut(it, 0, false)
}
it.nextIt.Close()
it.nextIt = it.qs.QuadIterator(it.dir, it.primaryIt.Result())
// Recurse -- return the first in the next set.
return it.Next()
}
// Next advances the iterator.
func (it *Fixed) Next() bool {
graph.NextLogIn(it)
if it.lastIndex == len(it.values) {
return graph.NextLogOut(it, nil, false)
}
out := it.values[it.lastIndex]
it.result = out
it.lastIndex++
return graph.NextLogOut(it, out, true)
}
// Returns advances the And iterator. Because the And is the intersection of its
// subiterators, it must choose one subiterator to produce a candidate, and check
// this value against the subiterators. A productive choice of primary iterator
// is therefore very important.
func (it *And) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
for graph.Next(it.primaryIt) {
curr := it.primaryIt.Result()
if it.subItsContain(curr, nil) {
it.result = curr
return graph.NextLogOut(it, curr, true)
}
}
it.err = it.primaryIt.Err()
return graph.NextLogOut(it, nil, false)
}
// Next() on an Int64 all iterator is a simple incrementing counter.
// Return the next integer, and mark it as the result.
func (it *Int64) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
if it.at == -1 {
return graph.NextLogOut(it, nil, false)
}
val := it.at
it.at = it.at + 1
if it.at > it.max {
it.at = -1
}
it.result = val
return graph.NextLogOut(it, val, true)
}
// Next advances the Not iterator. It returns whether there is another valid
// new value. It fetches the next value of the all iterator which is not
// contained by the primary iterator.
func (it *Not) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
for graph.Next(it.allIt) {
if curr := it.allIt.Result(); !it.primaryIt.Contains(curr) {
it.result = curr
it.runstats.ContainsNext += 1
return graph.NextLogOut(it, curr, true)
}
}
it.err = it.allIt.Err()
return graph.NextLogOut(it, nil, false)
}
// Next advances the subiterator, continuing until it returns a value which it
// has not previously seen.
func (it *Unique) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
for graph.Next(it.subIt) {
curr := it.subIt.Result()
if ok := it.seen[curr]; !ok {
it.result = curr
it.seen[curr] = true
return graph.NextLogOut(it, it.result, true)
}
}
it.err = it.subIt.Err()
return graph.NextLogOut(it, nil, false)
}
// Next advances the iterator. This is simpler than Contains. We have a
// subiterator we can get a value from, and we can take that resultant quad,
// pull our direction out of it, and return that.
func (it *HasA) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
if it.resultIt != nil {
it.resultIt.Close()
}
it.resultIt = &Null{}
if !graph.Next(it.primaryIt) {
it.err = it.primaryIt.Err()
return graph.NextLogOut(it, 0, false)
}
tID := it.primaryIt.Result()
val := it.qs.QuadDirection(tID, it.dir)
it.result = val
return graph.NextLogOut(it, val, true)
}
func (it *Iterator) Next() bool {
graph.NextLogIn(it)
if it.iter == nil {
return graph.NextLogOut(it, nil, false)
}
result, _, err := it.iter.Next()
if err != nil {
if err != io.EOF {
it.err = err
}
return graph.NextLogOut(it, nil, false)
}
if !it.checkValid(result) {
return it.Next()
}
it.result = result
return graph.NextLogOut(it, it.result, true)
}
func (it *Materialize) Next() bool {
graph.NextLogIn(it)
it.runstats.Next += 1
if !it.hasRun {
it.materializeSet()
}
if it.err != nil {
return false
}
if it.aborted {
n := graph.Next(it.subIt)
it.err = it.subIt.Err()
return n
}
it.index++
it.subindex = 0
if it.index >= len(it.values) {
return graph.NextLogOut(it, nil, false)
}
return graph.NextLogOut(it, it.Result(), true)
}
