rclone/backend/union/policy/newest.go

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package policy
import (
"context"
"path"
"sync"
"time"
"github.com/rclone/rclone/backend/union/upstream"
"github.com/rclone/rclone/fs"
)
func init() {
registerPolicy("newest", &Newest{})
}
// Newest policy picks the file / directory with the largest mtime
// It implies the existence of a path
type Newest struct {
EpAll
}
func (p *Newest) newest(ctx context.Context, upstreams []*upstream.Fs, filePath string) (*upstream.Fs, error) {
var wg sync.WaitGroup
ufs := make([]*upstream.Fs, len(upstreams))
mtimes := make([]time.Time, len(upstreams))
for i, u := range upstreams {
wg.Add(1)
i, u := i, u // Closure
go func() {
defer wg.Done()
rfs := u.RootFs
remote := path.Join(u.RootPath, filePath)
if e := findEntry(ctx, rfs, remote); e != nil {
ufs[i] = u
mtimes[i] = e.ModTime(ctx)
}
}()
}
wg.Wait()
maxMtime := time.Time{}
var newestFs *upstream.Fs
for i, u := range ufs {
if u != nil && mtimes[i].After(maxMtime) {
maxMtime = mtimes[i]
newestFs = u
}
}
if newestFs == nil {
return nil, fs.ErrorObjectNotFound
}
return newestFs, nil
}
func (p *Newest) newestEntries(entries []upstream.Entry) (upstream.Entry, error) {
var wg sync.WaitGroup
mtimes := make([]time.Time, len(entries))
ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
defer cancel()
for i, e := range entries {
wg.Add(1)
i, e := i, e // Closure
go func() {
defer wg.Done()
mtimes[i] = e.ModTime(ctx)
}()
}
wg.Wait()
maxMtime := time.Time{}
var newestEntry upstream.Entry
for i, t := range mtimes {
if t.After(maxMtime) {
maxMtime = t
newestEntry = entries[i]
}
}
if newestEntry == nil {
return nil, fs.ErrorObjectNotFound
}
return newestEntry, nil
}
// Action category policy, governing the modification of files and directories
func (p *Newest) Action(ctx context.Context, upstreams []*upstream.Fs, path string) ([]*upstream.Fs, error) {
if len(upstreams) == 0 {
return nil, fs.ErrorObjectNotFound
}
upstreams = filterRO(upstreams)
if len(upstreams) == 0 {
return nil, fs.ErrorPermissionDenied
}
u, err := p.newest(ctx, upstreams, path)
return []*upstream.Fs{u}, err
}
// ActionEntries is ACTION category policy but receiving a set of candidate entries
func (p *Newest) ActionEntries(entries ...upstream.Entry) ([]upstream.Entry, error) {
if len(entries) == 0 {
return nil, fs.ErrorObjectNotFound
}
entries = filterROEntries(entries)
if len(entries) == 0 {
return nil, fs.ErrorPermissionDenied
}
e, err := p.newestEntries(entries)
return []upstream.Entry{e}, err
}
// Create category policy, governing the creation of files and directories
func (p *Newest) Create(ctx context.Context, upstreams []*upstream.Fs, path string) ([]*upstream.Fs, error) {
if len(upstreams) == 0 {
return nil, fs.ErrorObjectNotFound
}
upstreams = filterNC(upstreams)
if len(upstreams) == 0 {
return nil, fs.ErrorPermissionDenied
}
u, err := p.newest(ctx, upstreams, path+"/..")
return []*upstream.Fs{u}, err
}
// CreateEntries is CREATE category policy but receiving a set of candidate entries
func (p *Newest) CreateEntries(entries ...upstream.Entry) ([]upstream.Entry, error) {
if len(entries) == 0 {
return nil, fs.ErrorObjectNotFound
}
entries = filterNCEntries(entries)
if len(entries) == 0 {
return nil, fs.ErrorPermissionDenied
}
e, err := p.newestEntries(entries)
return []upstream.Entry{e}, err
}
// Search category policy, governing the access to files and directories
func (p *Newest) Search(ctx context.Context, upstreams []*upstream.Fs, path string) (*upstream.Fs, error) {
if len(upstreams) == 0 {
return nil, fs.ErrorObjectNotFound
}
return p.newest(ctx, upstreams, path)
}
// SearchEntries is SEARCH category policy but receiving a set of candidate entries
func (p *Newest) SearchEntries(entries ...upstream.Entry) (upstream.Entry, error) {
if len(entries) == 0 {
return nil, fs.ErrorObjectNotFound
}
return p.newestEntries(entries)
}