channeldb: switch to Open/Create methods rather than New

Commit includes basic tests for Open/Create. Additionally, rather than
relying on btcwallet’s addmgr for encryption/decryption, this package
now exposes a simple crypto system interface.

channeldb/db.go

@@ -3,12 +3,12 @@ package channeldb
 import (
 	"bytes"
 	"encoding/binary"
+	"fmt"
 	"os"
 	"path/filepath"
 	"sync"
 
 	"github.com/boltdb/bolt"
-	"github.com/btcsuite/btcwallet/waddrmgr"
 )
 
 const (
@@ -16,64 +16,119 @@ const (
 )
 
 var (
-	endian = binary.BigEndian
+	// Big endian is the preferred byte order, due to cursor scans over integer
+	// keys iterating in order.
+	byteOrder = binary.BigEndian
 )
 
 var bufPool = &sync.Pool{
 	New: func() interface{} { return new(bytes.Buffer) },
 }
 
-// Store...
-// TODO(roasbeef): CHECKSUMS, REDUNDANCY, etc etc.
+// EncryptorDecryptor...
+// TODO(roasbeef): ability to rotate EncryptorDecryptor's across DB
+type EncryptorDecryptor interface {
+	Encrypt(in []byte) ([]byte, error)
+	Decrypt(in []byte) ([]byte, error)
+	OverheadSize() uint32
+}
+
+// DB...
 type DB struct {
-	// TODO(roasbeef): caching, etc?
-	addrmgr *waddrmgr.Manager
+	store *bolt.DB
 
-	db *bolt.DB
+	cryptoSystem EncryptorDecryptor
 }
 
-// Wipe...
-func (d *DB) Wipe() error {
-	return d.db.Update(func(tx *bolt.Tx) error {
-		return tx.DeleteBucket(openChannelBucket)
-	})
-}
-
-// New...
-// TODO(roasbeef): re-visit this dependancy...
-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
-			}
-		}
+// Open opens an existing channeldb created under the passed namespace with
+// sensitive data encrypted by the passed EncryptorDecryptor implementation.
+// TODO(roasbeef): versioning?
+func Open(dbPath string) (*DB, error) {
+	if !fileExists(dbPath) {
+		return nil, ErrNoExists
 	}
 
 	path := filepath.Join(dbPath, dbName)
-	boltDB, err := bolt.Open(path, 0600, nil)
+	bdb, err := bolt.Open(path, 0600, nil)
 	if err != nil {
 		return nil, err
 	}
 
-	return &DB{addrmgr, boltDB}, nil
-}
-
-// Open...
-// TODO(roasbeef): create+open, ditch New, fixes above
-func Open() *DB {
-	return nil
+	return &DB{store: bdb}, nil
 }
 
 // Create...
-func Create() *DB {
-	return nil
+func Create(dbPath string) (*DB, error) {
+	bdb, err := createChannelDB(dbPath)
+	if err != nil {
+		return nil, err
+	}
+
+	return &DB{store: bdb}, nil
+}
+
+// RegisterCryptoSystem...
+func (d *DB) RegisterCryptoSystem(ed EncryptorDecryptor) {
+	d.cryptoSystem = ed
+}
+
+// Wipe...
+func (d *DB) Wipe() error {
+	return d.store.Update(func(tx *bolt.Tx) error {
+		// TODO(roasbee): delete all other top-level buckets.
+		return tx.DeleteBucket(openChannelBucket)
+	})
 }
 
 // Close...
 func (d *DB) Close() error {
-	return d.db.Close()
+	return d.store.Close()
+}
+
+// createChannelDB...
+func createChannelDB(dbPath string) (*bolt.DB, error) {
+	if !fileExists(dbPath) {
+		if err := os.MkdirAll(dbPath, 0700); err != nil {
+			return nil, err
+		}
+	}
+
+	path := filepath.Join(dbPath, dbName)
+	bdb, err := bolt.Open(path, 0600, nil)
+	if err != nil {
+		return nil, err
+	}
+
+	err = bdb.Update(func(tx *bolt.Tx) error {
+		if _, err := tx.CreateBucket(openChannelBucket); err != nil {
+			return err
+		}
+
+		if _, err := tx.CreateBucket(closedChannelBucket); err != nil {
+			return err
+		}
+
+		if _, err := tx.CreateBucket(channelLogBucket); err != nil {
+			return err
+		}
+
+		return nil
+	})
+	if err != nil {
+		return nil, fmt.Errorf("unable to create new channeldb")
+	}
+
+	return bdb, nil
+}
+
+// fileExists...
+func fileExists(path string) bool {
+	if _, err := os.Stat(path); err != nil {
+		if os.IsNotExist(err) {
+			return false
+		}
+	}
+
+	return true
 }
 
-// TODO(roasbeef): SetCryptoSystem method...
-//  * don't have waddrmgr up before..

channeldb/db_test.go

@@ -0,0 +1,38 @@
+package channeldb
+
+import (
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func TestOpenNotCreated(t *testing.T) {
+	if _, err := Open("path doesn't exist"); err != ErrNoExists {
+		t.Fatalf("channeldb Open should fail due to non-existant dir")
+	}
+}
+
+func TestCreateThenOpen(t *testing.T) {
+	// First, create a temporary directory to be used for the duration of
+	// this test.
+	tempDirName, err := ioutil.TempDir("", "channeldb")
+	if err != nil {
+		t.Fatalf("unable to create temp dir: %v")
+	}
+	defer os.RemoveAll(tempDirName)
+
+	// Next, create channeldb for the first time.
+	cdb, err := Create(tempDirName)
+	if err != nil {
+		t.Fatalf("unable to create channeldb: %v", err)
+	}
+	if err := cdb.Close(); err != nil {
+		t.Fatalf("unable to close channeldb: %v", err)
+	}
+
+	// Open should now succeed as the cdb was created above.
+	cdb, err = Open(tempDirName)
+	if err != nil {
+		t.Fatalf("unable to open channeldb: %v", err)
+	}
+}

channeldb/error.go

@@ -1 +1,7 @@
 package channeldb
+
+import "fmt"
+
+var (
+	ErrNoExists = fmt.Errorf("channel db has not yet been created")
+)