Defined the Op interface.

fuseops/ops.go

@@ -22,8 +22,22 @@ import (
 	"time"
 
 	"github.com/jacobsa/bazilfuse"
+	"golang.org/x/net/context"
 )
 
+type Op interface {
+	// A context that can be used for long-running operations.
+	Context() context.Context
+
+	// Repond to the operation with the supplied error. If there is no error, set
+	// any necessary output fields and then call Respond(nil).
+	Respond(error)
+}
+
+////////////////////////////////////////////////////////////////////////
+// Setup
+////////////////////////////////////////////////////////////////////////
+
 // Sent once when mounting the file system. It must succeed in order for the
 // mount to succeed.
 type InitOp struct {