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package server
import (
"fmt"
"io/fs"
"os"
"path"
"path/filepath"
"slices"
"time"
"go.alanpearce.eu/website/internal/log"
"github.com/fsnotify/fsnotify"
"gitlab.com/tozd/go/errors"
)
type FileWatcher struct {
*fsnotify.Watcher
}
var (
l *log.Logger
ignores = []string{
"*.templ",
"*.go",
}
checkSettleInterval = 200 * time.Millisecond
)
func matches(name string) func(string) bool {
return func(pattern string) bool {
matched, err := path.Match(pattern, name)
if err != nil {
l.Warn("error checking watcher ignores", "error", err)
}
return matched
}
}
func ignored(pathname string) bool {
return slices.ContainsFunc(ignores, matches(path.Base(pathname)))
}
func NewFileWatcher(log *log.Logger) (*FileWatcher, error) {
watcher, err := fsnotify.NewWatcher()
if err != nil {
return nil, errors.WithMessage(err, "could not create watcher")
}
l = log
return &FileWatcher{watcher}, nil
}
func (watcher FileWatcher) AddRecursive(from string) error {
l.Debug("walking directory tree", "root", from)
err := filepath.WalkDir(from, func(path string, entry fs.DirEntry, err error) error {
if err != nil {
return errors.WithMessagef(err, "could not walk directory %s", path)
}
if entry.IsDir() {
l.Debug("adding directory to watcher", "path", path)
if err = watcher.Add(path); err != nil {
return errors.WithMessagef(err, "could not add directory %s to watcher", path)
}
}
return nil
})
return errors.WithMessage(err, "error walking directory tree")
}
func (watcher FileWatcher) Start(callback func(string)) {
var timer *time.Timer
for {
select {
case event := <-watcher.Events:
if !ignored(event.Name) {
l.Debug("watcher event", "name", event.Name, "op", event.Op.String())
if event.Has(fsnotify.Create) || event.Has(fsnotify.Rename) {
f, err := os.Stat(event.Name)
if err != nil {
l.Error(
fmt.Sprintf("error handling %s event: %v", event.Op.String(), err),
)
} else if f.IsDir() {
err = watcher.Add(event.Name)
if err != nil {
l.Error(fmt.Sprintf("error adding new folder to watcher: %v", err))
}
}
}
if event.Has(fsnotify.Rename) || event.Has(fsnotify.Write) ||
event.Has(fsnotify.Create) || event.Has(fsnotify.Chmod) {
if timer == nil {
timer = time.AfterFunc(checkSettleInterval, func() {
callback(event.Name)
})
}
timer.Reset(checkSettleInterval)
}
}
case err := <-watcher.Errors:
l.Error("error in watcher", "error", err)
}
}
}
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