go-gemini/io.go

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2021-02-23 18:49:42 -07:00
package gemini
import (
"bufio"
"context"
"io"
)
type contextReader struct {
ctx context.Context
done <-chan struct{}
cancel func()
rc io.ReadCloser
}
func (r *contextReader) Read(p []byte) (int, error) {
select {
case <-r.done:
r.rc.Close()
return 0, r.ctx.Err()
default:
}
n, err := r.rc.Read(p)
if err != nil {
r.cancel()
}
return n, err
}
func (r *contextReader) Close() error {
r.cancel()
return r.rc.Close()
}
type contextWriter struct {
ctx context.Context
done <-chan struct{}
cancel func()
wc io.WriteCloser
}
func (w *contextWriter) Write(b []byte) (int, error) {
select {
case <-w.done:
w.wc.Close()
return 0, w.ctx.Err()
default:
}
n, err := w.wc.Write(b)
if err != nil {
w.cancel()
}
return n, err
}
func (w *contextWriter) Close() error {
w.cancel()
return w.wc.Close()
}
type nopCloser struct {
io.Writer
}
func (nopCloser) Close() error {
return nil
}
type nopReadCloser struct{}
func (nopReadCloser) Read(p []byte) (int, error) {
return 0, io.EOF
}
func (nopReadCloser) Close() error {
return nil
}
type bufReadCloser struct {
br *bufio.Reader // used until empty
io.ReadCloser
}
func newBufReadCloser(br *bufio.Reader, rc io.ReadCloser) io.ReadCloser {
body := &bufReadCloser{ReadCloser: rc}
if br.Buffered() != 0 {
body.br = br
}
return body
}
func (b *bufReadCloser) Read(p []byte) (n int, err error) {
if b.br != nil {
if n := b.br.Buffered(); len(p) > n {
p = p[:n]
}
n, err = b.br.Read(p)
if b.br.Buffered() == 0 {
b.br = nil
}
return n, err
}
return b.ReadCloser.Read(p)
}