notmuch: use fswatcher to trigger directory count update

Use fswatcher to watch the underlying notmuch db to trigger directory
updates. Remove unused argument in the handleUpdateDirCounts function.
Call this function when listing directories to initialize counts when
starting aerc.

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, 37 insertions, 13 deletions

diff --git a/worker/notmuch/eventhandlers.go b/worker/notmuch/eventhandlers.go
index 7cd9c6fc..2b03d68b 100644
--- a/worker/notmuch/eventhandlers.go
+++ b/worker/notmuch/eventhandlers.go
@@ -12,15 +12,15 @@ import (
 )
 
 func (w *worker) handleNotmuchEvent(et eventType) error {
-	switch ev := et.(type) {
+	switch et.(type) {
 	case *updateDirCounts:
-		return w.handleUpdateDirCounts(ev)
+		return w.handleUpdateDirCounts()
 	default:
 		return errUnsupported
 	}
 }
 
-func (w *worker) handleUpdateDirCounts(ev eventType) error {
+func (w *worker) handleUpdateDirCounts() error {
 	if w.store != nil {
 		folders, err := w.store.FolderMap()
 		if err != nil {
diff --git a/worker/notmuch/lib/database.go b/worker/notmuch/lib/database.go
index 79bf5be3..a965bb62 100644
--- a/worker/notmuch/lib/database.go
+++ b/worker/notmuch/lib/database.go
@@ -62,6 +62,11 @@ func (db *DB) connect(writable bool) error {
 	return nil
 }
 
+// Returns the DB path
+func (db *DB) Path() string {
+	return db.db.Path()
+}
+
 // withConnection calls callback on the DB object, cleaning up upon return.
 // the error returned is from the connection attempt, if not successful,
 // or from the callback otherwise.
diff --git a/worker/notmuch/worker.go b/worker/notmuch/worker.go
index 3a5dc141..49e598bf 100644
--- a/worker/notmuch/worker.go
+++ b/worker/notmuch/worker.go
@@ -13,6 +13,7 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
+	"path"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -34,8 +35,6 @@ func init() {
 
 var errUnsupported = fmt.Errorf("unsupported command")
 
-const backgroundRefreshDelay = 1 * time.Minute
-
 type worker struct {
 	w                   *types.Worker
 	nmEvents            chan eventType
@@ -47,14 +46,21 @@ type worker struct {
 	db                  *notmuch.DB
 	setupErr            error
 	currentSortCriteria []*types.SortCriterion
+	watcher             types.FSWatcher
+	watcherDebounce     *time.Timer
 }
 
 // NewWorker creates a new notmuch worker with the provided worker.
 func NewWorker(w *types.Worker) (types.Backend, error) {
 	events := make(chan eventType, 20)
+	watcher, err := handlers.NewWatcher()
+	if err != nil {
+		return nil, fmt.Errorf("(%s) could not create file system watcher: %w", w.Name, err)
+	}
 	return &worker{
 		w:        w,
 		nmEvents: events,
+		watcher:  watcher,
 	}, nil
 }
 
@@ -81,6 +87,15 @@ func (w *worker) Run() {
 			if err != nil {
 				log.Errorf("notmuch event failure: %v", err)
 			}
+		case <-w.watcher.Events():
+			if w.watcherDebounce != nil {
+				w.watcherDebounce.Stop()
+			}
+			// Debounce FS changes
+			w.watcherDebounce = time.AfterFunc(50*time.Millisecond, func() {
+				defer log.PanicHandler()
+				w.nmEvents <- &updateDirCounts{}
+			})
 		}
 	}
 }
@@ -203,14 +218,13 @@ func (w *worker) handleConnect(msg *types.Connect) error {
 	}
 	w.done(msg)
 	w.emitLabelList()
-	go func() {
-		defer log.PanicHandler()
-
-		for {
-			w.nmEvents <- &updateDirCounts{}
-			time.Sleep(backgroundRefreshDelay)
-		}
-	}()
+	// Watch all the files in the xapian folder for changes. We'll debounce
+	// changes, so catching multiple is ok
+	dbPath := path.Join(w.db.Path(), ".notmuch", "xapian")
+	err = w.watcher.Configure(dbPath)
+	if err != nil {
+		return err
+	}
 	return nil
 }
 
@@ -241,6 +255,11 @@ func (w *worker) handleListDirectories(msg *types.ListDirectories) error {
 			},
 		}, nil)
 	}
+	// Update dir counts when listing directories
+	err := w.handleUpdateDirCounts()
+	if err != nil {
+		return err
+	}
 	w.done(msg)
 	return nil
 }