//go:build solaris

// +build solaris

package fsnotify

import (

	"errors"

)

// Watcher watches a set of paths, delivering events on a channel.

//

// A watcher should not be copied (e.g. pass it by pointer, rather than by

// value).

//

// # Linux notes

//

// When a file is removed a Remove event won't be emitted until all file

// descriptors are closed, and deletes will always emit a Chmod. For example:

//

//     fp := os.Open("file")

//     os.Remove("file")        // Triggers Chmod

//     fp.Close()               // Triggers Remove

//

// This is the event that inotify sends, so not much can be changed about this.

//

// The fs.inotify.max_user_watches sysctl variable specifies the upper limit

// for the number of watches per user, and fs.inotify.max_user_instances

// specifies the maximum number of inotify instances per user. Every Watcher you

// create is an "instance", and every path you add is a "watch".

//

// These are also exposed in /proc as /proc/sys/fs/inotify/max_user_watches and

// /proc/sys/fs/inotify/max_user_instances

//

// To increase them you can use sysctl or write the value to the /proc file:

//

//     # Default values on Linux 5.18

//     sysctl fs.inotify.max_user_watches=124983

//     sysctl fs.inotify.max_user_instances=128

//

// To make the changes persist on reboot edit /etc/sysctl.conf or

// /usr/lib/sysctl.d/50-default.conf (details differ per Linux distro; check

// your distro's documentation):

//

//     fs.inotify.max_user_watches=124983

//     fs.inotify.max_user_instances=128

//

// Reaching the limit will result in a "no space left on device" or "too many open

// files" error.

//

// # kqueue notes (macOS, BSD)

//

// kqueue requires opening a file descriptor for every file that's being watched;

// so if you're watching a directory with five files then that's six file

// descriptors. You will run in to your system's "max open files" limit faster on

// these platforms.

//

// The sysctl variables kern.maxfiles and kern.maxfilesperproc can be used to

// control the maximum number of open files, as well as /etc/login.conf on BSD

// systems.

//

// # macOS notes

//

// Spotlight indexing on macOS can result in multiple events (see [#15]). A

// temporary workaround is to add your folder(s) to the "Spotlight Privacy

// Settings" until we have a native FSEvents implementation (see [#11]).

//

// [#11]: https://github.com/fsnotify/fsnotify/issues/11

// [#15]: https://github.com/fsnotify/fsnotify/issues/15

type Watcher struct {

	// Events sends the filesystem change events.

	//

	// fsnotify can send the following events; a "path" here can refer to a

	// file, directory, symbolic link, or special file like a FIFO.

	//

	//   fsnotify.Create    A new path was created; this may be followed by one

	//                      or more Write events if data also gets written to a

	//                      file.

	//

	//   fsnotify.Remove    A path was removed.

	//

	//   fsnotify.Rename    A path was renamed. A rename is always sent with the

	//                      old path as Event.Name, and a Create event will be

	//                      sent with the new name. Renames are only sent for

	//                      paths that are currently watched; e.g. moving an

	//                      unmonitored file into a monitored directory will

	//                      show up as just a Create. Similarly, renaming a file

	//                      to outside a monitored directory will show up as

	//                      only a Rename.

	//

	//   fsnotify.Write     A file or named pipe was written to. A Truncate will

	//                      also trigger a Write. A single "write action"

	//                      initiated by the user may show up as one or multiple

	//                      writes, depending on when the system syncs things to

	//                      disk. For example when compiling a large Go program

	//                      you may get hundreds of Write events, so you

	//                      probably want to wait until you've stopped receiving

	//                      them (see the dedup example in cmd/fsnotify).

	//

	//   fsnotify.Chmod     Attributes were changed. On Linux this is also sent

	//                      when a file is removed (or more accurately, when a

	//                      link to an inode is removed). On kqueue it's sent

	//                      and on kqueue when a file is truncated. On Windows

	//                      it's never sent.

	Events chan Event

	// Errors sends any errors.

	Errors chan error

}

// NewWatcher creates a new Watcher.

func NewWatcher() (*Watcher, error) {

	return nil, errors.New("FEN based watcher not yet supported for fsnotify\n")

}

// Close removes all watches and closes the events channel.

func (w *Watcher) Close() error {

	return nil

}

// Add starts monitoring the path for changes.

//

// A path can only be watched once; attempting to watch it more than once will

// return an error. Paths that do not yet exist on the filesystem cannot be

// added. A watch will be automatically removed if the path is deleted.

//

// A path will remain watched if it gets renamed to somewhere else on the same

// filesystem, but the monitor will get removed if the path gets deleted and

// re-created, or if it's moved to a different filesystem.

//

// Notifications on network filesystems (NFS, SMB, FUSE, etc.) or special

// filesystems (/proc, /sys, etc.) generally don't work.

//

// # Watching directories

//

// All files in a directory are monitored, including new files that are created

// after the watcher is started. Subdirectories are not watched (i.e. it's

// non-recursive).

//

// # Watching files

//

// Watching individual files (rather than directories) is generally not

// recommended as many tools update files atomically. Instead of "just" writing

// to the file a temporary file will be written to first, and if successful the

// temporary file is moved to to destination removing the original, or some

// variant thereof. The watcher on the original file is now lost, as it no

// longer exists.

//

// Instead, watch the parent directory and use Event.Name to filter out files

// you're not interested in. There is an example of this in [cmd/fsnotify/file.go].

func (w *Watcher) Add(name string) error {

	return nil

}

// Remove stops monitoring the path for changes.

//

// Directories are always removed non-recursively. For example, if you added

// /tmp/dir and /tmp/dir/subdir then you will need to remove both.

//

// Removing a path that has not yet been added returns [ErrNonExistentWatch].

func (w *Watcher) Remove(name string) error {

	return nil

}