// Copyright 2018 Google Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package fs

import (
	"fmt"
	"sync/atomic"
)

// beforeSave is invoked by stateify.
func (d *Dirent) beforeSave() {
	// Refuse to save if the file has already been deleted (but still has
	// open fds, which is why the Dirent is still accessible). We know the
	// the restore opening of the file will always fail. This condition will
	// last until all the open fds and this Dirent are closed and released.
	//
	// Note that this is rejection rather than failure---it would be
	// perfectly OK to save---we are simply disallowing it here to prevent
	// generating non-restorable state dumps. As the program continues its
	// execution, it may become allowed to save again.
	if atomic.LoadInt32(&d.deleted) != 0 {
		n, _ := d.FullName(nil /* root */)
		panic(ErrSaveRejection{fmt.Errorf("deleted file %q still has open fds", n)})
	}
}

// afterLoad is invoked by stateify.
func (d *Dirent) afterLoad() {
	if d.userVisible {
		allDirents.add(d)
	}
}