コード例 #1
0
ファイル: datastore.go プロジェクト: admpub/bolt-datastore
func (bd *boltDatastore) Query(q query.Query) (query.Results, error) {
	qrb := query.NewResultBuilder(q)
	qrb.Process.Go(func(worker goprocess.Process) {
		bd.db.View(func(tx *bolt.Tx) error {

			buck := tx.Bucket(bd.bucketName)
			c := buck.Cursor()

			var prefix []byte
			if qrb.Query.Prefix != "" {
				prefix = []byte(qrb.Query.Prefix)
			}

			cur := 0
			sent := 0
			for k, v := c.Seek(prefix); k != nil; k, v = c.Next() {
				if cur < qrb.Query.Offset {
					cur++
					continue
				}
				if qrb.Query.Limit > 0 && sent >= qrb.Query.Limit {
					break
				}
				dk := ds.NewKey(string(k)).String()
				e := query.Entry{Key: dk}

				if !qrb.Query.KeysOnly {
					buf := make([]byte, len(v))
					copy(buf, v)
					e.Value = buf
				}

				select {
				case qrb.Output <- query.Result{Entry: e}: // we sent it out
					sent++
				case <-worker.Closing(): // client told us to end early.
					break
				}
				cur++
			}

			return nil
		})
	})

	// go wait on the worker (without signaling close)
	go qrb.Process.CloseAfterChildren()

	qr := qrb.Results()
	for _, f := range q.Filters {
		qr = query.NaiveFilter(qr, f)
	}
	for _, o := range q.Orders {
		qr = query.NaiveOrder(qr, o)
	}
	return qr, nil
}
コード例 #2
0
ファイル: datastore.go プロジェクト: rht/go-datastore
func (d *datastore) runQuery(worker goprocess.Process, qrb *dsq.ResultBuilder) {

	var rnge *util.Range
	if qrb.Query.Prefix != "" {
		rnge = util.BytesPrefix([]byte(qrb.Query.Prefix))
	}
	i := d.DB.NewIterator(rnge, nil)
	defer i.Release()

	// advance iterator for offset
	if qrb.Query.Offset > 0 {
		for j := 0; j < qrb.Query.Offset; j++ {
			i.Next()
		}
	}

	// iterate, and handle limit, too
	for sent := 0; i.Next(); sent++ {
		// end early if we hit the limit
		if qrb.Query.Limit > 0 && sent >= qrb.Query.Limit {
			break
		}

		k := ds.NewKey(string(i.Key())).String()
		e := dsq.Entry{Key: k}

		if !qrb.Query.KeysOnly {
			buf := make([]byte, len(i.Value()))
			copy(buf, i.Value())
			e.Value = buf
		}

		select {
		case qrb.Output <- dsq.Result{Entry: e}: // we sent it out
		case <-worker.Closing(): // client told us to end early.
			break
		}
	}

	if err := i.Error(); err != nil {
		select {
		case qrb.Output <- dsq.Result{Error: err}: // client read our error
		case <-worker.Closing(): // client told us to end.
			return
		}
	}
}