remote

type CreateOnSharedStrategy int

type Locator string

type ObjectKey struct {
	Locator    Locator
	ObjectName string
}

type ObjectReader interface {
	// ReadAt reads len(p) bytes into p starting at offset off.
	//
	// Does not return partial results; if offset + len(p) is past the end of the
	// object, an error is returned.
	//
	// Clients of ReadAt can execute parallel ReadAt calls on the same
	// ObjectReader.
	ReadAt(ctx context.Context, p []byte, offset int64) error

	Close() error
}

type Storage interface {
	io.Closer

	// ReadObject returns an ObjectReader that can be used to perform reads on an
	// object, along with the total size of the object.
	ReadObject(ctx context.Context, objName string) (_ ObjectReader, objSize int64, _ error)

	// CreateObject returns a writer for the object at the request name. A new
	// empty object is created if CreateObject is called on an existing object.
	//
	// A Writer *must* be closed via either Close, and if closing returns a
	// non-nil error, that error should be handled or reported to the user -- an
	// implementation may buffer written data until Close and only then return
	// an error, or Write may return an opaque io.EOF with the underlying cause
	// returned by the subsequent Close().
	//
	// TODO(radu): if we encounter some unrelated error while writing to the
	// WriteCloser, we'd want to abort the whole thing rather than letting Close
	// finalize the upload.
	CreateObject(objName string) (io.WriteCloser, error)

	// List enumerates files within the supplied prefix, returning a list of
	// objects within that prefix. If delimiter is non-empty, names which have the
	// same prefix, prior to the delimiter but after the prefix, are grouped into a
	// single result which is that prefix. The order that results are returned is
	// undefined. If a prefix is specified, the prefix is trimmed from the result
	// list.
	//
	// An example would be, if the storage contains objects a, b/4, b/5 and b/6,
	// these would be the return values:
	//   List("", "") -> ["a", "b/4", "b/5", "b/6"]
	//   List("", "/") -> ["a", "b"]
	//   List("b", "/") -> ["4", "5", "6"]
	//   List("b", "") -> ["/4", "/5", "/6"]
	List(prefix, delimiter string) ([]string, error)

	// Delete removes the named object from the store.
	Delete(objName string) error

	// Size returns the length of the named object in bytesWritten.
	Size(objName string) (int64, error)

	// IsNotExistError returns true if the given error (returned by a method in
	// this interface) indicates that the object does not exist.
	IsNotExistError(err error) bool
}

type StorageFactory interface {
	CreateStorage(locator Locator) (Storage, error)
}