channeldb: switch to bolt.DB instead of walletdb.DB

This decouples channeldb from btcwallet, and also allows us access to
bolt’s Batch() call.

channeldb/db.go

@@ -3,10 +3,16 @@ package channeldb
 import (
 	"bytes"
 	"encoding/binary"
+	"os"
+	"path/filepath"
 	"sync"
 
+	"github.com/boltdb/bolt"
 	"github.com/btcsuite/btcwallet/waddrmgr"
-	"github.com/btcsuite/btcwallet/walletdb"
+)
+
+const (
+	dbName = "channel.db"
 )
 
 var (
@@ -23,23 +29,34 @@ type DB struct {
 	// TODO(roasbeef): caching, etc?
 	addrmgr *waddrmgr.Manager
 
-	namespace walletdb.Namespace
+	db *bolt.DB
 }
 
 // Wipe...
 func (d *DB) Wipe() error {
-	return d.namespace.Update(func(tx walletdb.Tx) error {
-		rootBucket := tx.RootBucket()
-		// TODO(roasbeef): other buckets
-		return rootBucket.DeleteBucket(openChannelBucket)
+	return d.db.Update(func(tx *bolt.Tx) error {
+		return tx.DeleteBucket(openChannelBucket)
 	})
 }
 
 // New...
 // TODO(roasbeef): re-visit this dependancy...
-func New(addrmgr *waddrmgr.Manager, namespace walletdb.Namespace) *DB {
-	// TODO(roasbeef): create buckets if not created?
-	return &DB{addrmgr, namespace}
+func New(dbPath string, addrmgr *waddrmgr.Manager) (*DB, error) {
+	if _, err := os.Stat(dbPath); err != nil {
+		if os.IsNotExist(err) {
+			if err := os.MkdirAll(dbPath, 0700); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	path := filepath.Join(dbPath, dbName)
+	boltDB, err := bolt.Open(path, 0600, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	return &DB{addrmgr, boltDB}, nil
 }
 
 // Open...
@@ -52,3 +69,11 @@ func Open() *DB {
 func Create() *DB {
 	return nil
 }
+
+// Close...
+func (d *DB) Close() error {
+	return d.db.Close()
+}
+
+// TODO(roasbeef): SetCryptoSystem method...
+//  * don't have waddrmgr up before..