rebase: vendor ceph/go-ceph/cephfs/admin

The CephFS Admin package has been made available with go-ceph v0.6. This
will be used for provisioning and managing CephFS volumes.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

vendor/github.com/ceph/go-ceph/cephfs/admin/bytecount.go

@@ -0,0 +1,68 @@
+// +build !luminous,!mimic
+
+package admin
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// ByteCount represents the size of a volume in bytes.
+type ByteCount uint64
+
+// SI byte size constants. keep these private for now.
+const (
+	kibiByte ByteCount = 1024
+	mebiByte           = 1024 * kibiByte
+	gibiByte           = 1024 * mebiByte
+	tebiByte           = 1024 * gibiByte
+)
+
+// resizeValue returns a size value as a string, as needed by the subvolume
+// resize command json.
+func (bc ByteCount) resizeValue() string {
+	return uint64String(uint64(bc))
+}
+
+// QuotaSize interface values can be used to change the size of a volume.
+type QuotaSize interface {
+	resizeValue() string
+}
+
+// specialSize is a custom non-numeric quota size value.
+type specialSize string
+
+// resizeValue for a specialSize returns the original string value.
+func (s specialSize) resizeValue() string {
+	return string(s)
+}
+
+// Infinite is a special QuotaSize value that can be used to clear size limits
+// on a subvolume.
+const Infinite = specialSize("infinite")
+
+// quotaSizePlaceholder types are helpful to extract QuotaSize typed values
+// from JSON responses.
+type quotaSizePlaceholder struct {
+	Value QuotaSize
+}
+
+func (p *quotaSizePlaceholder) UnmarshalJSON(b []byte) error {
+	var val interface{}
+	if err := json.Unmarshal(b, &val); err != nil {
+		return err
+	}
+	switch v := val.(type) {
+	case string:
+		if v == string(Infinite) {
+			p.Value = Infinite
+		} else {
+			return fmt.Errorf("quota size: invalid string value: %q", v)
+		}
+	case float64:
+		p.Value = ByteCount(v)
+	default:
+		return fmt.Errorf("quota size: invalid type, string or number required: %v (%T)", val, val)
+	}
+	return nil
+}