Add read lock

replicator.go

@@ -1,18 +1,52 @@
 package litestream
 
+import (
+	"context"
+)
+
+// Replicator represents a method for replicating the snapshot & WAL data to
+// a remote destination.
 type Replicator interface {
+	Name() string
+	Type() string
+	BeginSnapshot(ctx context.Context) error
 }
 
+var _ Replicator = (*FileReplicator)(nil)
+
 // FileReplicator is a replicator that replicates a DB to a local file path.
 type FileReplicator struct {
-	db  *DB    // source database
-	dst string // destination path
+	db   *DB    // source database
+	name string // replicator name, optional
+	dst  string // destination path
 }
 
 // NewFileReplicator returns a new instance of FileReplicator.
-func NewFileReplicator(db *DB, dst string) *FileReplicator {
+func NewFileReplicator(db *DB, name, dst string) *FileReplicator {
 	return &FileReplicator{
-		db:  db,
-		dst: dst,
+		db:   db,
+		name: name,
+		dst:  dst,
 	}
 }
+
+// Name returns the name of the replicator. Returns the type if no name set.
+func (r *FileReplicator) Name() string {
+	if r.name != "" {
+		return r.name
+	}
+	return r.Type()
+}
+
+// Type returns the type of replicator.
+func (r *FileReplicator) Type() string {
+	return "file"
+}
+
+//
+func (r *FileReplicator) BeginSnapshot(ctx context.Context) error {
+	// TODO: Set snapshotting state to true.
+	// TODO: Read current generation.
+	// TODO: Copy database to destination.
+	return nil
+}