mirror of https://github.com/BTCPrivate/lnd.git
92 lines
2.1 KiB
Go
92 lines
2.1 KiB
Go
package channeldb
|
|
|
|
import (
|
|
"github.com/boltdb/bolt"
|
|
)
|
|
|
|
var (
|
|
// metaBucket stores all the meta information concerning the state of
|
|
// the database.
|
|
metaBucket = []byte("metadata")
|
|
|
|
// dbVersionKey is a boltdb key and it's used for storing/retrieving
|
|
// current database version.
|
|
dbVersionKey = []byte("dbp")
|
|
)
|
|
|
|
// Meta structure holds the database meta information.
|
|
type Meta struct {
|
|
// DbVersionNumber is the current schema version of the database.
|
|
DbVersionNumber uint32
|
|
}
|
|
|
|
// FetchMeta fetches the meta data from boltdb and returns filled meta
|
|
// structure. If transaction object is specified then it will be used rather
|
|
// than initiation creation of new one.
|
|
func (d *DB) FetchMeta(tx *bolt.Tx) (*Meta, error) {
|
|
meta := &Meta{}
|
|
fetchMeta := func(tx *bolt.Tx) error {
|
|
if metaBucket := tx.Bucket(metaBucket); metaBucket != nil {
|
|
fetchDbVersion(metaBucket, meta)
|
|
return nil
|
|
} else {
|
|
return ErrMetaNotFound
|
|
}
|
|
}
|
|
|
|
var err error
|
|
|
|
if tx == nil {
|
|
err = d.store.View(fetchMeta)
|
|
} else {
|
|
err = fetchMeta(tx)
|
|
}
|
|
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
return meta, nil
|
|
}
|
|
|
|
// PutMeta gets as input meta structure and put it into boltdb. If transaction
|
|
// object is specified then it will be used rather than initiation creation of
|
|
// new one.
|
|
func (d *DB) PutMeta(meta *Meta, tx *bolt.Tx) error {
|
|
putMeta := func(tx *bolt.Tx) error {
|
|
metaBucket := tx.Bucket(metaBucket)
|
|
if metaBucket == nil {
|
|
return ErrMetaNotFound
|
|
}
|
|
|
|
if err := putDbVersion(metaBucket, meta); err != nil {
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
if tx == nil {
|
|
return d.store.Update(putMeta)
|
|
} else {
|
|
return putMeta(tx)
|
|
}
|
|
}
|
|
|
|
func putDbVersion(metaBucket *bolt.Bucket, meta *Meta) error {
|
|
scratch := make([]byte, 4)
|
|
byteOrder.PutUint32(scratch, meta.DbVersionNumber)
|
|
if err := metaBucket.Put(dbVersionKey, scratch); err != nil {
|
|
return err
|
|
}
|
|
return nil
|
|
}
|
|
|
|
func fetchDbVersion(metaBucket *bolt.Bucket, meta *Meta) {
|
|
if data := metaBucket.Get(dbVersionKey); data != nil {
|
|
meta.DbVersionNumber = byteOrder.Uint32(data)
|
|
} else {
|
|
meta.DbVersionNumber = getLatestDBVersion(dbVersions)
|
|
}
|
|
}
|