ARM-software/golang-utils

package resource

import (
    "io"
    "sync"
)

type closeableResource struct {
    io.Closer
    mu                sync.RWMutex
    closeableResource io.Closer
    closed            bool
    description       string
}

func (c *closeableResource) IsClosed() bool {
    c.mu.RLock()
    defer c.mu.RUnlock()
    return c.closed
}

func (c *closeableResource) Close() error {
    c.mu.Lock()
    defer c.mu.Unlock()
    if c.closeableResource != nil {
        err := c.closeableResource.Close()
        if err != nil {
            return err
        }
    }
    c.closed = true
    c.closeableResource = nil
    return nil
}

func (c *closeableResource) String() string {
    c.mu.RLock()
    defer c.mu.RUnlock()
    return c.description
}

// NewCloseableResource returns a Closeable resource.
func NewCloseableResource(resource io.Closer, description string) ICloseableResource {
    return &closeableResource{
        closeableResource: resource,
        closed:            false,
        description:       description,
    }
}

type closeableNilResource struct {
}

func (c *closeableNilResource) Close() error {
    return nil
}

func (c *closeableNilResource) String() string {
    return "non closeable resource"
}

func (c *closeableNilResource) IsClosed() bool {
    return false
}

// NewNonCloseableResource returns a resource which cannot be closed.
func NewNonCloseableResource() ICloseableResource {
    return &closeableNilResource{}
}