add other session providers (#5963)

vendor/github.com/lunny/nodb/store/db.go

@@ -0,0 +1,61 @@
+package store
+
+import (
+	"github.com/lunny/nodb/store/driver"
+)
+
+type DB struct {
+	driver.IDB
+}
+
+func (db *DB) NewIterator() *Iterator {
+	it := new(Iterator)
+	it.it = db.IDB.NewIterator()
+
+	return it
+}
+
+func (db *DB) NewWriteBatch() WriteBatch {
+	return db.IDB.NewWriteBatch()
+}
+
+func (db *DB) NewSnapshot() (*Snapshot, error) {
+	var err error
+	s := &Snapshot{}
+	if s.ISnapshot, err = db.IDB.NewSnapshot(); err != nil {
+		return nil, err
+	}
+
+	return s, nil
+}
+
+func (db *DB) RangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+func (db *DB) RevRangeIterator(min []byte, max []byte, rangeType uint8) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{0, -1})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (db *DB) RangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
+
+//count < 0, unlimit.
+//
+//offset must >= 0, if < 0, will get nothing.
+func (db *DB) RevRangeLimitIterator(min []byte, max []byte, rangeType uint8, offset int, count int) *RangeLimitIterator {
+	return NewRevRangeLimitIterator(db.NewIterator(), &Range{min, max, rangeType}, &Limit{offset, count})
+}
+
+func (db *DB) Begin() (*Tx, error) {
+	tx, err := db.IDB.Begin()
+	if err != nil {
+		return nil, err
+	}
+
+	return &Tx{tx}, nil
+}