gorush/vendor/github.com/asdine/storm/scan.go

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package storm
import (
"bytes"
"github.com/boltdb/bolt"
)
// A BucketScanner scans a Node for a list of buckets
type BucketScanner interface {
// PrefixScan scans the root buckets for keys matching the given prefix.
PrefixScan(prefix string) []Node
// PrefixScan scans the buckets in this node for keys matching the given prefix.
RangeScan(min, max string) []Node
}
// PrefixScan scans the buckets in this node for keys matching the given prefix.
func (n *node) PrefixScan(prefix string) []Node {
if n.tx != nil {
return n.prefixScan(n.tx, prefix)
}
var nodes []Node
n.readTx(func(tx *bolt.Tx) error {
nodes = n.prefixScan(tx, prefix)
return nil
})
return nodes
}
func (n *node) prefixScan(tx *bolt.Tx, prefix string) []Node {
var (
prefixBytes = []byte(prefix)
nodes []Node
c = n.cursor(tx)
)
for k, v := c.Seek(prefixBytes); k != nil && bytes.HasPrefix(k, prefixBytes); k, v = c.Next() {
if v != nil {
continue
}
nodes = append(nodes, n.From(string(k)))
}
return nodes
}
// RangeScan scans the buckets in this node over a range such as a sortable time range.
func (n *node) RangeScan(min, max string) []Node {
if n.tx != nil {
return n.rangeScan(n.tx, min, max)
}
var nodes []Node
n.readTx(func(tx *bolt.Tx) error {
nodes = n.rangeScan(tx, min, max)
return nil
})
return nodes
}
func (n *node) rangeScan(tx *bolt.Tx, min, max string) []Node {
var (
minBytes = []byte(min)
maxBytes = []byte(max)
nodes []Node
c = n.cursor(tx)
)
for k, v := c.Seek(minBytes); k != nil && bytes.Compare(k, maxBytes) <= 0; k, v = c.Next() {
if v != nil {
continue
}
nodes = append(nodes, n.From(string(k)))
}
return nodes
}
func (n *node) cursor(tx *bolt.Tx) *bolt.Cursor {
var c *bolt.Cursor
if len(n.rootBucket) > 0 {
c = n.GetBucket(tx).Cursor()
} else {
c = tx.Cursor()
}
return c
}