// reader. This ignores any object properties.
func NewGetObjectReaderFromReader(r io.Reader, oi ObjectInfo, opts ObjectOptions, cleanupFns ...func()) (*GetObjectReader, error) {
	if opts.CheckPrecondFn != nil && opts.CheckPrecondFn(oi) {
		// Call the cleanup funcs
		for i := len(cleanupFns) - 1; i >= 0; i-- {
			cleanupFns[i]()
		}
		return nil, PreConditionFailed{}
	}
	return &GetObjectReader{
		ObjInfo:    oi,

// operation(s) on the object.
func (er erasureObjects) newMultipartUpload(ctx context.Context, bucket string, object string, opts ObjectOptions) (*NewMultipartUploadResult, error) {
	if opts.CheckPrecondFn != nil {
		if !opts.NoLock {
			ns := er.NewNSLock(bucket, object)
			lkctx, err := ns.GetLock(ctx, globalOperationTimeout)
			if err != nil {
				return nil, err
			}
			ctx = lkctx.Context()

		return
	}

	if r.Header.Get(xhttp.Range) != "" {
		writeErrorResponse(ctx, w, errorCodes.ToAPIErr(ErrInvalidRange), r.URL)
		return
	}

	// Validate pre-conditions if any.
	opts.CheckPrecondFn = func(oi ObjectInfo) bool {
		if _, err := DecryptObjectInfo(&oi, r); err != nil {
			writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
			return true
		}

		return checkPreconditions(ctx, w, r, oi, opts)

	}

	if r.Header.Get(xhttp.IfMatch) != "" {
		opts.HasIfMatch = true
	}
	if opts.PreserveETag != "" ||
		r.Header.Get(xhttp.IfMatch) != "" ||
		r.Header.Get(xhttp.IfNoneMatch) != "" {
		opts.CheckPrecondFn = func(oi ObjectInfo) bool {
			if _, err := DecryptObjectInfo(&oi, r); err != nil {
				writeErrorResponse(ctx, w, toAPIError(ctx, err), r.URL)
				return true
			}

	PartNumberMarker    int                 // used in GetObjectAttributes. Signals the part number after which results should be returned
	PartNumber          int                 // only useful in case of GetObject/HeadObject
	CheckPrecondFn      CheckPreconditionFn // only set during GetObject/HeadObject/CopyObjectPart preconditional valuation
	EvalMetadataFn      EvalMetadataFn      // only set for retention settings, meant to be used only when updating metadata in-place.