forked from machinebox/progress
/
writer.go
51 lines (44 loc) · 797 Bytes
/
writer.go
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package progress
import (
"io"
"sync"
)
// Writer counts the bytes written through it.
type Writer struct {
w io.Writer
lock sync.RWMutex // protects n and err
n int64
err error
}
// NewWriter gets a Writer that counts the number
// of bytes written.
func NewWriter(w io.Writer) *Writer {
return &Writer{
w: w,
}
}
func (w *Writer) Write(p []byte) (n int, err error) {
n, err = w.w.Write(p)
w.lock.Lock()
w.n += int64(n)
w.err = err
w.lock.Unlock()
return
}
// N gets the number of bytes that have been written
// so far.
func (w *Writer) N() int64 {
var n int64
w.lock.RLock()
n = w.n
w.lock.RUnlock()
return n
}
// Err gets the last error from the Writer.
func (w *Writer) Err() error {
var err error
w.lock.RLock()
err = w.err
w.lock.RUnlock()
return err
}