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package resource_pool
import (
"sync/atomic"
"errors"
)
// A resource handle managed by a resource pool.
type ManagedHandle interface {
// This returns the handle's resource location.
ResourceLocation() string
// This returns the underlying resource handle (or error if the handle
// is no longer active).
Handle() (interface{}, error)
// This returns the resource pool which owns this handle.
Owner() ResourcePool
// The releases the underlying resource handle to the caller and marks the
// managed handle as inactive. The caller is responsible for cleaning up
// the released handle. This returns nil if the managed handle no longer
// owns the resource.
ReleaseUnderlyingHandle() interface{}
// This indicates a user is done with the handle and releases the handle
// back to the resource pool.
Release() error
// This indicates the handle is an invalid state, and that the
// connection should be discarded from the connection pool.
Discard() error
}
// A physical implementation of ManagedHandle
type managedHandleImpl struct {
location string
handle interface{}
pool ResourcePool
isActive int32 // atomic bool
options Options
}
// This creates a managed handle wrapper.
func NewManagedHandle(
resourceLocation string,
handle interface{},
pool ResourcePool,
options Options) ManagedHandle {
h := &managedHandleImpl{
location: resourceLocation,
handle: handle,
pool: pool,
options: options,
}
atomic.StoreInt32(&h.isActive, 1)
return h
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) ResourceLocation() string {
return c.location
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) Handle() (interface{}, error) {
if atomic.LoadInt32(&c.isActive) == 0 {
return c.handle, errors.New("Resource handle is no longer valid")
}
return c.handle, nil
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) Owner() ResourcePool {
return c.pool
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) ReleaseUnderlyingHandle() interface{} {
if atomic.CompareAndSwapInt32(&c.isActive, 1, 0) {
return c.handle
}
return nil
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) Release() error {
return c.pool.Release(c)
}
// See ManagedHandle for documentation.
func (c *managedHandleImpl) Discard() error {
return c.pool.Discard(c)
}
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