burke/zeus

//go:build !darwin
// +build !darwin

package filemonitor

import (
    "time"

    "github.com/fsnotify/fsnotify"
)

type fsnotifyMonitor struct {
    gatheringMonitor
    watcher *fsnotify.Watcher
}

const flagsWorthReloadingFor = fsnotify.Write | fsnotify.Remove | fsnotify.Rename

func NewFileMonitor(fileChangeDelay time.Duration) (FileMonitor, error) {
    watcher, err := fsnotify.NewWatcher()
    if err != nil {
        return nil, err
    }

    f := fsnotifyMonitor{
        watcher: watcher,
    }
    f.fileChangeDelay = fileChangeDelay
    f.changes = make(chan string)

    go f.serveListeners()
    go f.watch()

    return &f, nil
}

func (f *fsnotifyMonitor) Add(file string) error {
    if err := f.watcher.Add(file); err != nil {
        return err
    }

    return nil
}

func (f *fsnotifyMonitor) Close() error {
    return f.watcher.Close()
}

func (f *fsnotifyMonitor) watch() {
    // Detect zero value and return
    // otherwise debounce

    for event := range f.watcher.Events {
        if (event.Op & flagsWorthReloadingFor) == 0 {
            continue
        }

        f.changes <- event.Name
    }

    close(f.changes)
}