crypto/cipher: StreamWriter.Closer docs + behavior change
Don't panic when the underlying Writer isn't a Closer. And
document what Close does and clarify that it's not a Flush.
R=golang-dev, agl
CC=golang-dev
https://golang.org/cl/10310043
diff --git a/src/pkg/crypto/cipher/io.go b/src/pkg/crypto/cipher/io.go
index 807e8da..3938c0a 100644
--- a/src/pkg/crypto/cipher/io.go
+++ b/src/pkg/crypto/cipher/io.go
@@ -25,6 +25,8 @@
// StreamWriter wraps a Stream into an io.Writer. It calls XORKeyStream
// to process each slice of data which passes through. If any Write call
// returns short then the StreamWriter is out of sync and must be discarded.
+// A StreamWriter has no internal buffering; Close does not need
+// to be called to flush write data.
type StreamWriter struct {
S Stream
W io.Writer
@@ -43,8 +45,11 @@
return
}
+// Close closes the underlying Writer and returns its Close return value, if the Writer
+// is also an io.Closer. Otherwise it returns nil.
func (w StreamWriter) Close() error {
- // This saves us from either requiring a WriteCloser or having a
- // StreamWriterCloser.
- return w.W.(io.Closer).Close()
+ if c, ok := w.W.(io.Closer); ok {
+ return c.Close()
+ }
+ return nil
}
