Example #1
0
func (qs *QuadStore) indexOf(t quad.Quad) (int64, bool) {
	min := maxInt
	var tree *b.Tree
	for d := quad.Subject; d <= quad.Label; d++ {
		sid := t.Get(d)
		if d == quad.Label && sid == "" {
			continue
		}
		id, ok := qs.idMap[sid]
		// If we've never heard about a node, it must not exist
		if !ok {
			return 0, false
		}
		index, ok := qs.index.Get(d, id)
		if !ok {
			// If it's never been indexed in this direction, it can't exist.
			return 0, false
		}
		if l := index.Len(); l < min {
			min, tree = l, index
		}
	}
	it := NewIterator(tree, "", qs)

	for it.Next() {
		val := it.Result()
		if t == qs.log[val.(int64)].Quad {
			return val.(int64), true
		}
	}
	return 0, false
}
Example #2
0
func (qs *QuadStore) createKeyFor(d [4]quad.Direction, q quad.Quad) []byte {
	key := make([]byte, 0, 2+(hashSize*4))
	// TODO(kortschak) Remove dependence on String() method.
	key = append(key, []byte{d[0].Prefix(), d[1].Prefix()}...)
	key = append(key, hashOf(q.Get(d[0]))...)
	key = append(key, hashOf(q.Get(d[1]))...)
	key = append(key, hashOf(q.Get(d[2]))...)
	key = append(key, hashOf(q.Get(d[3]))...)
	return key
}
Example #3
0
func (qs *QuadStore) buildQuadWrite(batch *leveldb.Batch, q quad.Quad, id int64, isAdd bool) error {
	var entry IndexEntry
	data, err := qs.db.Get(qs.createKeyFor(spo, q), qs.readopts)
	if err != nil && err != leveldb.ErrNotFound {
		glog.Error("could not access DB to prepare index: ", err)
		return err
	}
	if err == nil {
		// We got something.
		err = json.Unmarshal(data, &entry)
		if err != nil {
			return err
		}
	} else {
		entry.Quad = q
	}

	if isAdd && len(entry.History)%2 == 1 {
		glog.Errorf("attempt to add existing quad %v: %#v", entry, q)
		return graph.ErrQuadExists
	}
	if !isAdd && len(entry.History)%2 == 0 {
		glog.Error("attempt to delete non-existent quad %v: %#c", entry, q)
		return graph.ErrQuadNotExist
	}

	entry.History = append(entry.History, id)

	bytes, err := json.Marshal(entry)
	if err != nil {
		glog.Errorf("could not write to buffer for entry %#v: %s", entry, err)
		return err
	}
	batch.Put(qs.createKeyFor(spo, q), bytes)
	batch.Put(qs.createKeyFor(osp, q), bytes)
	batch.Put(qs.createKeyFor(pos, q), bytes)
	if q.Get(quad.Label) != "" {
		batch.Put(qs.createKeyFor(cps, q), bytes)
	}
	return nil
}