// Copyright 2012 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 !plan9

// Package fsnotify provides a platform-independent interface for file system notifications.

package fsnotify

import (

	"bytes"

	"errors"

	"fmt"

)

// Event represents a single file system notification.

type Event struct {

	Name string // Relative path to the file or directory.

	Op   Op     // File operation that triggered the event.

}

// Op describes a set of file operations.

type Op uint32

// These are the generalized file operations that can trigger a notification.

const (

	Create Op = 1 << iota

	Write

	Remove

	Rename

	Chmod

)

func (op Op) String() string {

	// Use a buffer for efficient string concatenation

	var buffer bytes.Buffer

	if op&Create == Create {

		buffer.WriteString("|CREATE")

	}

	if op&Remove == Remove {

		buffer.WriteString("|REMOVE")

	}

	if op&Write == Write {

		buffer.WriteString("|WRITE")

	}

	if op&Rename == Rename {

		buffer.WriteString("|RENAME")

	}

	if op&Chmod == Chmod {

		buffer.WriteString("|CHMOD")

	}

	if buffer.Len() == 0 {

		return ""

	}

	return buffer.String()[1:] // Strip leading pipe

}

// String returns a string representation of the event in the form

// "file: REMOVE|WRITE|..."

func (e Event) String() string {

	return fmt.Sprintf("%q: %s", e.Name, e.Op.String())

}

// Common errors that can be reported by a watcher

var (

	ErrEventOverflow = errors.New("fsnotify queue overflow")

)