rclone/backend/union/policy/epff.go

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package policy
import (
"context"
"path"
"github.com/rclone/rclone/backend/union/upstream"
"github.com/rclone/rclone/fs"
)
func init() {
registerPolicy("epff", &EpFF{})
}
// EpFF stands for existing path, first found
// Given the order of the candidates, act on the first one found where the relative path exists.
type EpFF struct{}
func (p *EpFF) epff(ctx context.Context, upstreams []*upstream.Fs, filePath string) (*upstream.Fs, error) {
ch := make(chan *upstream.Fs)
for _, u := range upstreams {
u := u // Closure
go func() {
rfs := u.RootFs
remote := path.Join(u.RootPath, filePath)
if findEntry(ctx, rfs, remote) == nil {
u = nil
}
ch <- u
}()
}
var u *upstream.Fs
for i := 0; i < len(upstreams); i++ {
u = <-ch
if u != nil {
// close remaining goroutines
go func(num int) {
defer close(ch)
for i := 0; i < num; i++ {
<-ch
}
}(len(upstreams) - 1 - i)
}
}
if u == nil {
return nil, fs.ErrorObjectNotFound
}
return u, nil
}
// Action category policy, governing the modification of files and directories
func (p *EpFF) 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.epff(ctx, upstreams, path)
return []*upstream.Fs{u}, err
}
// ActionEntries is ACTION category policy but receving a set of candidate entries
func (p *EpFF) 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
}
return entries[:1], nil
}
// Create category policy, governing the creation of files and directories
func (p *EpFF) 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.epff(ctx, upstreams, path+"/..")
return []*upstream.Fs{u}, err
}
// CreateEntries is CREATE category policy but receving a set of candidate entries
func (p *EpFF) 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
}
return entries[:1], nil
}
// Search category policy, governing the access to files and directories
func (p *EpFF) Search(ctx context.Context, upstreams []*upstream.Fs, path string) (*upstream.Fs, error) {
if len(upstreams) == 0 {
return nil, fs.ErrorObjectNotFound
}
return p.epff(ctx, upstreams, path)
}
// SearchEntries is SEARCH category policy but receving a set of candidate entries
func (p *EpFF) SearchEntries(entries ...upstream.Entry) (upstream.Entry, error) {
if len(entries) == 0 {
return nil, fs.ErrorObjectNotFound
}
return entries[0], nil
}