Adding upstream version 1.21.8.upstream/1.21.8

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 44 insertions, 0 deletions

diff --git a/src/net/splice_linux.go b/src/net/splice_linux.go
new file mode 100644
index 0000000..ab2ab70
--- /dev/null
+++ b/src/net/splice_linux.go
@@ -0,0 +1,44 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package net
+
+import (
+	"internal/poll"
+	"io"
+)
+
+// splice transfers data from r to c using the splice system call to minimize
+// copies from and to userspace. c must be a TCP connection. Currently, splice
+// is only enabled if r is a TCP or a stream-oriented Unix connection.
+//
+// If splice returns handled == false, it has performed no work.
+func splice(c *netFD, r io.Reader) (written int64, err error, handled bool) {
+	var remain int64 = 1<<63 - 1 // by default, copy until EOF
+	lr, ok := r.(*io.LimitedReader)
+	if ok {
+		remain, r = lr.N, lr.R
+		if remain <= 0 {
+			return 0, nil, true
+		}
+	}
+
+	var s *netFD
+	if tc, ok := r.(*TCPConn); ok {
+		s = tc.fd
+	} else if uc, ok := r.(*UnixConn); ok {
+		if uc.fd.net != "unix" {
+			return 0, nil, false
+		}
+		s = uc.fd
+	} else {
+		return 0, nil, false
+	}
+
+	written, handled, sc, err := poll.Splice(&c.pfd, &s.pfd, remain)
+	if lr != nil {
+		lr.N -= written
+	}
+	return written, wrapSyscallError(sc, err), handled
+}