storj/pkg/utils/io.go

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2019-01-24 20:15:10 +00:00
// Copyright (C) 2019 Storj Labs, Inc.
// See LICENSE for copying information.
package utils
// ReaderSource takes a src func and turns it into an io.Reader
type ReaderSource struct {
src func() ([]byte, error)
buf []byte
err error
}
// NewReaderSource makes a new ReaderSource
func NewReaderSource(src func() ([]byte, error)) *ReaderSource {
return &ReaderSource{src: src}
}
// Read implements io.Reader
func (rs *ReaderSource) Read(p []byte) (n int, err error) {
if rs.err != nil {
return 0, rs.err
}
if len(rs.buf) == 0 {
rs.buf, rs.err = rs.src()
}
n = copy(p, rs.buf)
rs.buf = rs.buf[n:]
return n, rs.err
}