rclone/backend/union/policy/eplno.go
2020-03-21 18:11:24 +00:00

117 lines
3.2 KiB
Go

package policy
import (
"context"
"math"
"github.com/rclone/rclone/backend/union/upstream"
"github.com/rclone/rclone/fs"
)
func init() {
registerPolicy("eplno", &EpLno{})
}
// EpLno stands for existing path, least number of objects
// Of all the candidates on which the path exists choose the one with the least number of objects
type EpLno struct {
EpAll
}
func (p *EpLno) lno(upstreams []*upstream.Fs) (*upstream.Fs, error) {
var minNumObj int64 = math.MaxInt64
var lnoUpstream *upstream.Fs
for _, u := range upstreams {
numObj, err := u.GetNumObjects()
if err != nil {
fs.LogPrintf(fs.LogLevelNotice, nil,
"Number of Objects is not supported for upstream %s, treating as 0", u.Name())
}
if minNumObj > numObj {
minNumObj = numObj
lnoUpstream = u
}
}
if lnoUpstream == nil {
return nil, fs.ErrorObjectNotFound
}
return lnoUpstream, nil
}
func (p *EpLno) lnoEntries(entries []upstream.Entry) (upstream.Entry, error) {
var minNumObj int64 = math.MaxInt64
var lnoEntry upstream.Entry
for _, e := range entries {
numObj, err := e.UpstreamFs().GetNumObjects()
if err != nil {
fs.LogPrintf(fs.LogLevelNotice, nil,
"Number of Objects is not supported for upstream %s, treating as 0", e.UpstreamFs().Name())
}
if minNumObj > numObj {
minNumObj = numObj
lnoEntry = e
}
}
return lnoEntry, nil
}
// Action category policy, governing the modification of files and directories
func (p *EpLno) Action(ctx context.Context, upstreams []*upstream.Fs, path string) ([]*upstream.Fs, error) {
upstreams, err := p.EpAll.Action(ctx, upstreams, path)
if err != nil {
return nil, err
}
u, err := p.lno(upstreams)
return []*upstream.Fs{u}, err
}
// ActionEntries is ACTION category policy but receving a set of candidate entries
func (p *EpLno) ActionEntries(entries ...upstream.Entry) ([]upstream.Entry, error) {
entries, err := p.EpAll.ActionEntries(entries...)
if err != nil {
return nil, err
}
e, err := p.lnoEntries(entries)
return []upstream.Entry{e}, err
}
// Create category policy, governing the creation of files and directories
func (p *EpLno) Create(ctx context.Context, upstreams []*upstream.Fs, path string) ([]*upstream.Fs, error) {
upstreams, err := p.EpAll.Create(ctx, upstreams, path)
if err != nil {
return nil, err
}
u, err := p.lno(upstreams)
return []*upstream.Fs{u}, err
}
// CreateEntries is CREATE category policy but receving a set of candidate entries
func (p *EpLno) CreateEntries(entries ...upstream.Entry) ([]upstream.Entry, error) {
entries, err := p.EpAll.CreateEntries(entries...)
if err != nil {
return nil, err
}
e, err := p.lnoEntries(entries)
return []upstream.Entry{e}, err
}
// Search category policy, governing the access to files and directories
func (p *EpLno) Search(ctx context.Context, upstreams []*upstream.Fs, path string) (*upstream.Fs, error) {
if len(upstreams) == 0 {
return nil, fs.ErrorObjectNotFound
}
upstreams, err := p.epall(ctx, upstreams, path)
if err != nil {
return nil, err
}
return p.lno(upstreams)
}
// SearchEntries is SEARCH category policy but receving a set of candidate entries
func (p *EpLno) SearchEntries(entries ...upstream.Entry) (upstream.Entry, error) {
if len(entries) == 0 {
return nil, fs.ErrorObjectNotFound
}
return p.lnoEntries(entries)
}