Initial commit

Proof-of-concept implementation. Bugs will occur.

vendor/github.com/hanwen/go-fuse/v2/splice/pair_linux.go

@@ -0,0 +1,54 @@
+// Copyright 2016 the Go-FUSE 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 splice
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"syscall"
+)
+
+func (p *Pair) LoadFromAt(fd uintptr, sz int, off int64) (int, error) {
+	n, err := syscall.Splice(int(fd), &off, p.w, nil, sz, 0)
+	return int(n), err
+}
+
+func (p *Pair) LoadFrom(fd uintptr, sz int) (int, error) {
+	if sz > p.size {
+		return 0, fmt.Errorf("LoadFrom: not enough space %d, %d",
+			sz, p.size)
+	}
+
+	n, err := syscall.Splice(int(fd), nil, p.w, nil, sz, 0)
+	if err != nil {
+		err = os.NewSyscallError("Splice load from", err)
+	}
+	return int(n), err
+}
+
+func (p *Pair) WriteTo(fd uintptr, n int) (int, error) {
+	m, err := syscall.Splice(p.r, nil, int(fd), nil, int(n), 0)
+	if err != nil {
+		err = os.NewSyscallError("Splice write", err)
+	}
+	return int(m), err
+}
+
+const _SPLICE_F_NONBLOCK = 0x2
+
+func (p *Pair) discard() {
+	_, err := syscall.Splice(p.r, nil, devNullFD(), nil, int(p.size), _SPLICE_F_NONBLOCK)
+	if err == syscall.EAGAIN {
+		// all good.
+	} else if err != nil {
+		errR := syscall.Close(p.r)
+		errW := syscall.Close(p.w)
+
+		// This can happen if something closed our fd
+		// inadvertently (eg. double close)
+		log.Panicf("splicing into /dev/null: %v (close R %d '%v', close W %d '%v')", err, p.r, errR, p.w, errW)
+	}
+}