dotcloud/docker

package cleanups

import (
    "context"

    "github.com/docker/docker/internal/multierror"
)

type Composite struct {
    cleanups []func(context.Context) error
}

// Add adds a cleanup to be called.
func (c *Composite) Add(f func(context.Context) error) {
    c.cleanups = append(c.cleanups, f)
}

// Call calls all cleanups in reverse order and returns an error combining all
// non-nil errors.
func (c *Composite) Call(ctx context.Context) error {
    err := call(ctx, c.cleanups)
    c.cleanups = nil
    return err
}

// Release removes all cleanups, turning Call into a no-op.
// Caller still can call the cleanups by calling the returned function
// which is equivalent to calling the Call before Release was called.
func (c *Composite) Release() func(context.Context) error {
    cleanups := c.cleanups
    c.cleanups = nil
    return func(ctx context.Context) error {
        return call(ctx, cleanups)
    }
}

func call(ctx context.Context, cleanups []func(context.Context) error) error {
    var errs []error
    for idx := len(cleanups) - 1; idx >= 0; idx-- {
        c := cleanups[idx]
        errs = append(errs, c(ctx))
    }
    return multierror.Join(errs...)
}