--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/vendor/github.com/fsnotify/fsnotify/inotify_poller.go	Sat Sep 29 18:09:54 2018 +0200
@@ -0,0 +1,187 @@
+// Copyright 2015 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.
+
+// +build linux
+
+package fsnotify
+
+import (
+	"errors"
+
+	"golang.org/x/sys/unix"
+)
+
+type fdPoller struct {
+	fd   int    // File descriptor (as returned by the inotify_init() syscall)
+	epfd int    // Epoll file descriptor
+	pipe [2]int // Pipe for waking up
+}
+
+func emptyPoller(fd int) *fdPoller {
+	poller := new(fdPoller)
+	poller.fd = fd
+	poller.epfd = -1
+	poller.pipe[0] = -1
+	poller.pipe[1] = -1
+	return poller
+}
+
+// Create a new inotify poller.
+// This creates an inotify handler, and an epoll handler.
+func newFdPoller(fd int) (*fdPoller, error) {
+	var errno error
+	poller := emptyPoller(fd)
+	defer func() {
+		if errno != nil {
+			poller.close()
+		}
+	}()
+	poller.fd = fd
+
+	// Create epoll fd
+	poller.epfd, errno = unix.EpollCreate1(0)
+	if poller.epfd == -1 {
+		return nil, errno
+	}
+	// Create pipe; pipe[0] is the read end, pipe[1] the write end.
+	errno = unix.Pipe2(poller.pipe[:], unix.O_NONBLOCK)
+	if errno != nil {
+		return nil, errno
+	}
+
+	// Register inotify fd with epoll
+	event := unix.EpollEvent{
+		Fd:     int32(poller.fd),
+		Events: unix.EPOLLIN,
+	}
+	errno = unix.EpollCtl(poller.epfd, unix.EPOLL_CTL_ADD, poller.fd, &event)
+	if errno != nil {
+		return nil, errno
+	}
+
+	// Register pipe fd with epoll
+	event = unix.EpollEvent{
+		Fd:     int32(poller.pipe[0]),
+		Events: unix.EPOLLIN,
+	}
+	errno = unix.EpollCtl(poller.epfd, unix.EPOLL_CTL_ADD, poller.pipe[0], &event)
+	if errno != nil {
+		return nil, errno
+	}
+
+	return poller, nil
+}
+
+// Wait using epoll.
+// Returns true if something is ready to be read,
+// false if there is not.
+func (poller *fdPoller) wait() (bool, error) {
+	// 3 possible events per fd, and 2 fds, makes a maximum of 6 events.
+	// I don't know whether epoll_wait returns the number of events returned,
+	// or the total number of events ready.
+	// I decided to catch both by making the buffer one larger than the maximum.
+	events := make([]unix.EpollEvent, 7)
+	for {
+		n, errno := unix.EpollWait(poller.epfd, events, -1)
+		if n == -1 {
+			if errno == unix.EINTR {
+				continue
+			}
+			return false, errno
+		}
+		if n == 0 {
+			// If there are no events, try again.
+			continue
+		}
+		if n > 6 {
+			// This should never happen. More events were returned than should be possible.
+			return false, errors.New("epoll_wait returned more events than I know what to do with")
+		}
+		ready := events[:n]
+		epollhup := false
+		epollerr := false
+		epollin := false
+		for _, event := range ready {
+			if event.Fd == int32(poller.fd) {
+				if event.Events&unix.EPOLLHUP != 0 {
+					// This should not happen, but if it does, treat it as a wakeup.
+					epollhup = true
+				}
+				if event.Events&unix.EPOLLERR != 0 {
+					// If an error is waiting on the file descriptor, we should pretend
+					// something is ready to read, and let unix.Read pick up the error.
+					epollerr = true
+				}
+				if event.Events&unix.EPOLLIN != 0 {
+					// There is data to read.
+					epollin = true
+				}
+			}
+			if event.Fd == int32(poller.pipe[0]) {
+				if event.Events&unix.EPOLLHUP != 0 {
+					// Write pipe descriptor was closed, by us. This means we're closing down the
+					// watcher, and we should wake up.
+				}
+				if event.Events&unix.EPOLLERR != 0 {
+					// If an error is waiting on the pipe file descriptor.
+					// This is an absolute mystery, and should never ever happen.
+					return false, errors.New("Error on the pipe descriptor.")
+				}
+				if event.Events&unix.EPOLLIN != 0 {
+					// This is a regular wakeup, so we have to clear the buffer.
+					err := poller.clearWake()
+					if err != nil {
+						return false, err
+					}
+				}
+			}
+		}
+
+		if epollhup || epollerr || epollin {
+			return true, nil
+		}
+		return false, nil
+	}
+}
+
+// Close the write end of the poller.
+func (poller *fdPoller) wake() error {
+	buf := make([]byte, 1)
+	n, errno := unix.Write(poller.pipe[1], buf)
+	if n == -1 {
+		if errno == unix.EAGAIN {
+			// Buffer is full, poller will wake.
+			return nil
+		}
+		return errno
+	}
+	return nil
+}
+
+func (poller *fdPoller) clearWake() error {
+	// You have to be woken up a LOT in order to get to 100!
+	buf := make([]byte, 100)
+	n, errno := unix.Read(poller.pipe[0], buf)
+	if n == -1 {
+		if errno == unix.EAGAIN {
+			// Buffer is empty, someone else cleared our wake.
+			return nil
+		}
+		return errno
+	}
+	return nil
+}
+
+// Close all poller file descriptors, but not the one passed to it.
+func (poller *fdPoller) close() {
+	if poller.pipe[1] != -1 {
+		unix.Close(poller.pipe[1])
+	}
+	if poller.pipe[0] != -1 {
+		unix.Close(poller.pipe[0])
+	}
+	if poller.epfd != -1 {
+		unix.Close(poller.epfd)
+	}
+}