enhance(sync): remove sync-stop-chan and simplify the stop process

src/main/frontend/fs/sync.cljs

@@ -2025,11 +2025,6 @@
   (chan 1))
 (def full-sync-mult (async/mult full-sync-chan))
 
-(def stop-sync-chan
-  "offer `true` to this chan will stop current `SyncManager`"
-  (chan 1))
-(def stop-sync-mult (async/mult stop-sync-chan))
-
 (def remote->local-sync-chan
   "offer `true` to this chan will trigger a remote->local sync"
   (chan 1))
@@ -2661,7 +2656,7 @@
                *txid ^:mutable state ^:mutable remote-change-chan ^:mutable *ws *stopped? *paused?
                ^:mutable ops-chan
                ;; control chans
-               private-full-sync-chan private-stop-sync-chan private-remote->local-sync-chan
+               private-full-sync-chan private-remote->local-sync-chan
                private-remote->local-full-sync-chan private-pause-resume-chan]
   Object
   (schedule [this next-state args reason]
@@ -2696,30 +2691,30 @@
     (set! ratelimit-local-changes-chan (<ratelimit local->remote-syncer local-changes-revised-chan))
     (setup-local->remote! local->remote-syncer)
     (async/tap full-sync-mult private-full-sync-chan)
-    (async/tap stop-sync-mult private-stop-sync-chan)
     (async/tap remote->local-sync-mult private-remote->local-sync-chan)
     (async/tap remote->local-full-sync-mult private-remote->local-full-sync-chan)
     (async/tap pause-resume-mult private-pause-resume-chan)
     (go-loop []
-      (let [{:keys [stop remote->local remote->local-full-sync local->remote-full-sync local->remote resume pause]}
+      (let [{:keys [remote->local remote->local-full-sync local->remote-full-sync local->remote resume pause stop]}
             (async/alt!
-             private-stop-sync-chan {:stop true}
              private-remote->local-full-sync-chan {:remote->local-full-sync true}
              private-remote->local-sync-chan {:remote->local true}
              private-full-sync-chan {:local->remote-full-sync true}
              private-pause-resume-chan ([v] (if v {:resume true} {:pause true}))
              remote-change-chan ([v] (println "remote change:" v) {:remote->local v})
              ratelimit-local-changes-chan ([v]
-                                           (let [rest-v (util/drain-chan ratelimit-local-changes-chan)
-                                                 vs     (cons v rest-v)]
-                                             (println "local changes:" vs)
-                                             {:local->remote vs}))
+                                           (if (nil? v)
+                                             {:stop true}
+                                             (let [rest-v (util/drain-chan ratelimit-local-changes-chan)
+                                                   vs     (cons v rest-v)]
+                                               (println "local changes:" vs)
+                                               {:local->remote vs})))
              (timeout (* 20 60 1000)) {:local->remote-full-sync true}
              :priority true)]
         (cond
           stop
-          (do (util/drain-chan ops-chan)
-              (>! ops-chan {:stop true}))
+          nil
+
           remote->local-full-sync
           (do (util/drain-chan ops-chan)
               (>! ops-chan {:remote->local-full-sync true})
@@ -2774,8 +2769,9 @@
                       :data  {:graph-uuid graph-uuid
                               :epoch      (tc/to-epoch (t/now))}})
     (go-loop []
-      (let [{:keys [resume]} (<! ops-chan)]
-        (if resume
+      (let [{:keys [resume] :as result} (<! ops-chan)]
+        (cond
+          resume
           (let [{:keys [remote->local remote->local-full-sync local->remote local->remote-full-sync] :as resume-state}
                 (get @*resume-state graph-uuid)]
             (resume-state--reset graph-uuid)
@@ -2797,6 +2793,11 @@
                                       :resume-state resume-state
                                       :epoch        (tc/to-epoch (t/now))}})
             (<! (.schedule this ::idle nil :resume)))
+
+          (nil? result)
+          (<! (.schedule this ::stop nil nil))
+
+          :else
           (recur)))))
 
   (idle [this]
@@ -2804,7 +2805,7 @@
       (let [{:keys [stop remote->local local->remote local->remote-full-sync remote->local-full-sync pause] :as result}
             (<! ops-chan)]
         (cond
-          stop
+          (or stop (nil? result))
           (<! (.schedule this ::stop nil nil))
           remote->local
           (<! (.schedule this ::remote->local {:remote remote->local} {:remote-changed remote->local}))
@@ -2891,7 +2892,7 @@
                                       :epoch      (tc/to-epoch (t/now))}})
             (let [next-state (if (string/includes? (str (ex-cause unknown)) "404 Not Found")
                                ;; TODO: this should never happen
-                               ::pause
+                               ::stop
                                ;; if any other exception occurred, re-exec remote->local-full-sync
                                ::remote->local-full-sync)]
               (.schedule this next-state nil nil)))))))
@@ -3001,9 +3002,7 @@
       (when-not @*stopped?
         (vreset! *stopped? true)
         (ws-stop! *ws)
-        (offer! private-stop-sync-chan true)
         (async/untap full-sync-mult private-full-sync-chan)
-        (async/untap stop-sync-mult private-stop-sync-chan)
         (async/untap remote->local-sync-mult private-remote->local-sync-chan)
         (async/untap remote->local-full-sync-mult private-remote->local-full-sync-chan)
         (async/untap pause-resume-mult private-pause-resume-chan)
@@ -3011,14 +3010,9 @@
         (stop-local->remote! local->remote-syncer)
         (stop-remote->local! remote->local-syncer)
         (<! (<rsapi-cancel-all-requests))
-        (debug/pprint ["stop sync-manager, graph-uuid" graph-uuid "base-path" base-path])
         (swap! *sync-state sync-state--update-state ::stop)
-        (loop []
-          (if (not= ::stop state)
-            (do
-              (<! (timeout 100))
-              (recur))
-            (reset! current-sm-graph-uuid nil))))))
+        (reset! current-sm-graph-uuid nil)
+        (debug/pprint ["stop sync-manager, graph-uuid" graph-uuid "base-path" base-path]))))
 
   IStopped?
   (-stopped? [_]
@@ -3044,7 +3038,7 @@
     (.set-local->remote-syncer! remote->local-syncer local->remote-syncer)
     (swap! *sync-state sync-state--update-current-syncing-graph-uuid graph-uuid)
     (->SyncManager user-uuid graph-uuid base-path *sync-state local->remote-syncer remote->local-syncer remoteapi-with-stop
-                   nil *txid nil nil nil *stopped? *paused? nil (chan 1) (chan 1) (chan 1) (chan 1) (chan 1))))
+                   nil *txid nil nil nil *stopped? *paused? nil (chan 1) (chan 1) (chan 1) (chan 1))))
 
 (defn sync-manager-singleton
   [user-uuid graph-uuid base-path repo txid *sync-state]