mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-17 20:00:23 +00:00
134 lines
3.8 KiB
Go
134 lines
3.8 KiB
Go
//
|
|
// Written by Maxim Khitrov (November 2012)
|
|
//
|
|
|
|
package flowrate
|
|
|
|
import (
|
|
"errors"
|
|
"io"
|
|
)
|
|
|
|
// ErrLimit is returned by the Writer when a non-blocking write is short due to
|
|
// the transfer rate limit.
|
|
var ErrLimit = errors.New("flowrate: flow rate limit exceeded")
|
|
|
|
// Limiter is implemented by the Reader and Writer to provide a consistent
|
|
// interface for monitoring and controlling data transfer.
|
|
type Limiter interface {
|
|
Done() int64
|
|
Status() Status
|
|
SetTransferSize(bytes int64)
|
|
SetLimit(new int64) (old int64)
|
|
SetBlocking(new bool) (old bool)
|
|
}
|
|
|
|
// Reader implements io.ReadCloser with a restriction on the rate of data
|
|
// transfer.
|
|
type Reader struct {
|
|
io.Reader // Data source
|
|
*Monitor // Flow control monitor
|
|
|
|
limit int64 // Rate limit in bytes per second (unlimited when <= 0)
|
|
block bool // What to do when no new bytes can be read due to the limit
|
|
}
|
|
|
|
// NewReader restricts all Read operations on r to limit bytes per second.
|
|
func NewReader(r io.Reader, limit int64) *Reader {
|
|
return &Reader{r, New(0, 0), limit, true}
|
|
}
|
|
|
|
// Read reads up to len(p) bytes into p without exceeding the current transfer
|
|
// rate limit. It returns (0, nil) immediately if r is non-blocking and no new
|
|
// bytes can be read at this time.
|
|
func (r *Reader) Read(p []byte) (n int, err error) {
|
|
p = p[:r.Limit(len(p), r.limit, r.block)]
|
|
if len(p) > 0 {
|
|
n, err = r.IO(r.Reader.Read(p))
|
|
}
|
|
return
|
|
}
|
|
|
|
// SetLimit changes the transfer rate limit to new bytes per second and returns
|
|
// the previous setting.
|
|
func (r *Reader) SetLimit(new int64) (old int64) {
|
|
old, r.limit = r.limit, new
|
|
return
|
|
}
|
|
|
|
// SetBlocking changes the blocking behavior and returns the previous setting. A
|
|
// Read call on a non-blocking reader returns immediately if no additional bytes
|
|
// may be read at this time due to the rate limit.
|
|
func (r *Reader) SetBlocking(new bool) (old bool) {
|
|
old, r.block = r.block, new
|
|
return
|
|
}
|
|
|
|
// Close closes the underlying reader if it implements the io.Closer interface.
|
|
func (r *Reader) Close() error {
|
|
defer r.Done()
|
|
if c, ok := r.Reader.(io.Closer); ok {
|
|
return c.Close()
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Writer implements io.WriteCloser with a restriction on the rate of data
|
|
// transfer.
|
|
type Writer struct {
|
|
io.Writer // Data destination
|
|
*Monitor // Flow control monitor
|
|
|
|
limit int64 // Rate limit in bytes per second (unlimited when <= 0)
|
|
block bool // What to do when no new bytes can be written due to the limit
|
|
}
|
|
|
|
// NewWriter restricts all Write operations on w to limit bytes per second. The
|
|
// transfer rate and the default blocking behavior (true) can be changed
|
|
// directly on the returned *Writer.
|
|
func NewWriter(w io.Writer, limit int64) *Writer {
|
|
return &Writer{w, New(0, 0), limit, true}
|
|
}
|
|
|
|
// Write writes len(p) bytes from p to the underlying data stream without
|
|
// exceeding the current transfer rate limit. It returns (n, ErrLimit) if w is
|
|
// non-blocking and no additional bytes can be written at this time.
|
|
func (w *Writer) Write(p []byte) (n int, err error) {
|
|
var c int
|
|
for len(p) > 0 && err == nil {
|
|
s := p[:w.Limit(len(p), w.limit, w.block)]
|
|
if len(s) > 0 {
|
|
c, err = w.IO(w.Writer.Write(s))
|
|
} else {
|
|
return n, ErrLimit
|
|
}
|
|
p = p[c:]
|
|
n += c
|
|
}
|
|
return
|
|
}
|
|
|
|
// SetLimit changes the transfer rate limit to new bytes per second and returns
|
|
// the previous setting.
|
|
func (w *Writer) SetLimit(new int64) (old int64) {
|
|
old, w.limit = w.limit, new
|
|
return
|
|
}
|
|
|
|
// SetBlocking changes the blocking behavior and returns the previous setting. A
|
|
// Write call on a non-blocking writer returns as soon as no additional bytes
|
|
// may be written at this time due to the rate limit.
|
|
func (w *Writer) SetBlocking(new bool) (old bool) {
|
|
old, w.block = w.block, new
|
|
return
|
|
}
|
|
|
|
// Close closes the underlying writer if it implements the io.Closer interface.
|
|
func (w *Writer) Close() error {
|
|
defer w.Done()
|
|
if c, ok := w.Writer.(io.Closer); ok {
|
|
return c.Close()
|
|
}
|
|
return nil
|
|
}
|