kairos-agent/pkg/utils/cleanstack.go

/*
Copyright © 2022 SUSE LLC

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 utils

import (
	"github.com/hashicorp/go-multierror"
)

type CleanJob func() error

// NewCleanStack returns a new stack.
func NewCleanStack() *CleanStack {
	return &CleanStack{}
}

// Stack is a basic LIFO stack that resizes as needed.
type CleanStack struct {
	jobs  []CleanJob
	count int
}

// Push adds a node to the stack
func (clean *CleanStack) Push(job CleanJob) {
	clean.jobs = append(clean.jobs[:clean.count], job)
	clean.count++
}

// Pop removes and returns a node from the stack in last to first order.
func (clean *CleanStack) Pop() CleanJob {
	if clean.count == 0 {
		return nil
	}
	clean.count--
	return clean.jobs[clean.count]
}

// Cleanup runs the whole cleanup stack. In case of error it runs all jobs
// and returns the first error occurrence.
func (clean *CleanStack) Cleanup(err error) error {
	var errs error
	if err != nil {
		errs = multierror.Append(errs, err)
	}
	for clean.count > 0 {
		job := clean.Pop()
		err = job()
		if err != nil {
			errs = multierror.Append(errs, err)
		}
	}
	return errs
}