ceph-csi/vendor/github.com/ceph/go-ceph/rados/object_iter.go

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package rados
// #cgo LDFLAGS: -lrados
// #include <rados/librados.h>
//
import "C"
// Iter supports iterating over objects in the ioctx.
type Iter struct {
ctx C.rados_list_ctx_t
err error
entry string
namespace string
}
// IterToken supports reporting on and seeking to different positions.
type IterToken uint32
// Iter returns a Iterator object that can be used to list the object names in the current pool
func (ioctx *IOContext) Iter() (*Iter, error) {
iter := Iter{}
if cerr := C.rados_nobjects_list_open(ioctx.ioctx, &iter.ctx); cerr < 0 {
return nil, getError(cerr)
}
return &iter, nil
}
// Token returns a token marking the current position of the iterator. To be used in combination with Iter.Seek()
func (iter *Iter) Token() IterToken {
return IterToken(C.rados_nobjects_list_get_pg_hash_position(iter.ctx))
}
// Seek moves the iterator to the position indicated by the token.
func (iter *Iter) Seek(token IterToken) {
C.rados_nobjects_list_seek(iter.ctx, C.uint32_t(token))
}
// Next retrieves the next object name in the pool/namespace iterator.
// Upon a successful invocation (return value of true), the Value method should
// be used to obtain the name of the retrieved object name. When the iterator is
// exhausted, Next returns false. The Err method should used to verify whether the
// end of the iterator was reached, or the iterator received an error.
//
// Example:
// iter := pool.Iter()
// defer iter.Close()
// for iter.Next() {
// fmt.Printf("%v\n", iter.Value())
// }
// return iter.Err()
//
func (iter *Iter) Next() bool {
var cEntry *C.char
var cNamespace *C.char
if cerr := C.rados_nobjects_list_next(iter.ctx, &cEntry, nil, &cNamespace); cerr < 0 {
iter.err = getError(cerr)
return false
}
iter.entry = C.GoString(cEntry)
iter.namespace = C.GoString(cNamespace)
return true
}
// Value returns the current value of the iterator (object name), after a successful call to Next.
func (iter *Iter) Value() string {
if iter.err != nil {
return ""
}
return iter.entry
}
// Namespace returns the namespace associated with the current value of the iterator (object name), after a successful call to Next.
func (iter *Iter) Namespace() string {
if iter.err != nil {
return ""
}
return iter.namespace
}
// Err checks whether the iterator has encountered an error.
func (iter *Iter) Err() error {
if iter.err == ErrNotFound {
return nil
}
return iter.err
}
// Close the iterator cursor on the server. Be aware that iterators are not closed automatically
// at the end of iteration.
func (iter *Iter) Close() {
C.rados_nobjects_list_close(iter.ctx)
}