fswatcher: add a darwin fswatcher implementation

Add a darwin implementation of FSWatcher using the fsevents package. The
implementation is behind a darwin build flag.

Co-authored-by: Ben Cohen <ben@bencohen.net>
Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>
Tested-by: Ben Lee-Cohen <ben@lee-cohen.com>
Acked-by: Robin Jarry <robin@jarry.cc>

3 files changed, 94 insertions, 0 deletions

diff --git a/worker/lib/watchers/darwin/darwin.go b/worker/lib/watchers/darwin/darwin.go
new file mode 100644
index 00000000..e20761f3
--- /dev/null
+++ b/worker/lib/watchers/darwin/darwin.go
@@ -0,0 +1,84 @@
+//go:build darwin
+// +build darwin
+
+package darwin
+
+import (
+	"time"
+
+	"git.sr.ht/~rjarry/aerc/log"
+	"git.sr.ht/~rjarry/aerc/worker/handlers"
+	"git.sr.ht/~rjarry/aerc/worker/types"
+	"github.com/fsnotify/fsevents"
+)
+
+func init() {
+	handlers.RegisterWatcherFactory("darwin", newDarwinWatcher)
+}
+
+type darwinWatcher struct {
+	ch        chan *types.FSEvent
+	w         *fsevents.EventStream
+	watcherCh chan []fsevents.Event
+}
+
+func newDarwinWatcher() (types.FSWatcher, error) {
+	watcher := &darwinWatcher{
+		watcherCh: make(chan []fsevents.Event),
+		ch:        make(chan *types.FSEvent),
+		w: &fsevents.EventStream{
+			Flags:   fsevents.FileEvents | fsevents.WatchRoot,
+			Latency: 500 * time.Millisecond,
+		},
+	}
+	return watcher, nil
+}
+
+func (w *darwinWatcher) watch() {
+	defer log.PanicHandler()
+	for events := range w.w.Events {
+		for _, ev := range events {
+			switch {
+			case ev.Flags&fsevents.ItemCreated > 0:
+				w.ch <- &types.FSEvent{
+					Operation: types.FSCreate,
+					Path:      ev.Path,
+				}
+			case ev.Flags&fsevents.ItemRenamed > 0:
+				w.ch <- &types.FSEvent{
+					Operation: types.FSRename,
+					Path:      ev.Path,
+				}
+			case ev.Flags&fsevents.ItemRemoved > 0:
+				w.ch <- &types.FSEvent{
+					Operation: types.FSRemove,
+					Path:      ev.Path,
+				}
+			}
+		}
+	}
+}
+
+func (w *darwinWatcher) Configure(root string) error {
+	dev, err := fsevents.DeviceForPath(root)
+	if err != nil {
+		return err
+	}
+	w.w.Device = dev
+	w.w.Paths = []string{root}
+	w.w.Start()
+	go w.watch()
+	return nil
+}
+
+func (w *darwinWatcher) Events() chan *types.FSEvent {
+	return w.ch
+}
+
+func (w *darwinWatcher) Add(p string) error {
+	return nil
+}
+
+func (w *darwinWatcher) Remove(p string) error {
+	return nil
+}
diff --git a/worker/maildir/worker.go b/worker/maildir/worker.go
index 11bab4ea..a94792bc 100644
--- a/worker/maildir/worker.go
+++ b/worker/maildir/worker.go
@@ -313,6 +313,10 @@ func (w *Worker) handleConfigure(msg *types.Configure) error {
 		return err
 	}
 	w.c = c
+	err = w.watcher.Configure(dir)
+	if err != nil {
+		return err
+	}
 	log.Debugf("configured base maildir: %s", dir)
 	return nil
 }
diff --git a/worker/watcher_darwin.go b/worker/watcher_darwin.go
new file mode 100644
index 00000000..fa1af712
--- /dev/null
+++ b/worker/watcher_darwin.go
@@ -0,0 +1,6 @@
+//go:build darwin
+// +build darwin
+
+package worker
+
+import _ "git.sr.ht/~rjarry/aerc/worker/lib/watchers/darwin"