moby/libnetwork/idm/idm.go
Brian Goff a0a473125b Fix libnetwork imports
After moving libnetwork to this repo, we need to update all the import
paths for libnetwork to point to docker/docker/libnetwork instead of
docker/libnetwork.
This change implements that.

Signed-off-by: Brian Goff <cpuguy83@gmail.com>
2021-06-01 21:51:23 +00:00

76 lines
2 KiB
Go

// Package idm manages reservation/release of numerical ids from a configured set of contiguous ids
package idm
import (
"errors"
"fmt"
"github.com/docker/docker/libnetwork/bitseq"
"github.com/docker/docker/libnetwork/datastore"
)
// Idm manages the reservation/release of numerical ids from a contiguous set
type Idm struct {
start uint64
end uint64
handle *bitseq.Handle
}
// New returns an instance of id manager for a [start,end] set of numerical ids
func New(ds datastore.DataStore, id string, start, end uint64) (*Idm, error) {
if id == "" {
return nil, errors.New("Invalid id")
}
if end <= start {
return nil, fmt.Errorf("Invalid set range: [%d, %d]", start, end)
}
h, err := bitseq.NewHandle("idm", ds, id, 1+end-start)
if err != nil {
return nil, fmt.Errorf("failed to initialize bit sequence handler: %s", err.Error())
}
return &Idm{start: start, end: end, handle: h}, nil
}
// GetID returns the first available id in the set
func (i *Idm) GetID(serial bool) (uint64, error) {
if i.handle == nil {
return 0, errors.New("ID set is not initialized")
}
ordinal, err := i.handle.SetAny(serial)
return i.start + ordinal, err
}
// GetSpecificID tries to reserve the specified id
func (i *Idm) GetSpecificID(id uint64) error {
if i.handle == nil {
return errors.New("ID set is not initialized")
}
if id < i.start || id > i.end {
return errors.New("Requested id does not belong to the set")
}
return i.handle.Set(id - i.start)
}
// GetIDInRange returns the first available id in the set within a [start,end] range
func (i *Idm) GetIDInRange(start, end uint64, serial bool) (uint64, error) {
if i.handle == nil {
return 0, errors.New("ID set is not initialized")
}
if start < i.start || end > i.end {
return 0, errors.New("Requested range does not belong to the set")
}
ordinal, err := i.handle.SetAnyInRange(start-i.start, end-i.start, serial)
return i.start + ordinal, err
}
// Release releases the specified id
func (i *Idm) Release(id uint64) {
i.handle.Unset(id - i.start)
}