Make wrap watchable

src/reagent/ratom.cljs

@@ -315,7 +315,8 @@
 
 ;;; wrap
 
-(deftype Wrapper [^:mutable state callback ^:mutable changed]
+(deftype Wrapper [^:mutable state callback ^:mutable changed
+                  ^:mutable watches]
 
   IAtom
 
@@ -324,10 +325,13 @@
 
   IReset
   (-reset! [this newval]
-           (set! changed true)
+    (let [oldval state]
-           (set! state newval)
+      (set! changed true)
-           (callback newval)
+      (set! state newval)
-           state)
+      (when-not (nil? watches)
+        (-notify-watches this oldval newval))
+      (callback newval)
+      newval))
 
   ISwap
   (-swap! [a f]
@@ -349,6 +353,17 @@
                (= state (.-state other))
                (= callback (.-callback other))))
 
+  IWatchable
+  (-notify-watches [this oldval newval]
+    (reduce-kv (fn [_ key f]
+                 (f key this oldval newval)
+                 nil)
+               nil watches))
+  (-add-watch [this key f]
+    (set! watches (assoc watches key f)))
+  (-remove-watch [this key]
+    (set! watches (dissoc watches key)))
+
   IPrintWithWriter
   (-pr-writer [_ writer opts]
     (-write writer "#<wrap: ")
@@ -358,4 +373,5 @@
 (defn make-wrapper [value callback-fn args]
   (Wrapper. value
             (util/partial-ifn. callback-fn args nil)
-            false))
+            false nil))
+

test/testcursor.cljs

@@ -11,18 +11,6 @@
 (defn running [] (rv/running))
 (defn dispose [v] (rv/dispose! v))
 
-(defn ratom-perf []
-  (dbg "ratom-perf")
-  (let [a (rv/atom {})
-        mid (reaction (inc @a))
-        res (run!
-             (inc @mid))]
-    (time (dotimes [x 100000]
-            (swap! a inc)))
-    (dispose res)))
-
-;; (ratom-perf)
-
 (deftest basic-cursor
   (let [runs (running)
         start-base (rv/atom {:a {:b {:c 0}}})
@@ -351,7 +339,7 @@
     (is (= runs (running)))))
 
 
-(deftest atom-behaviors
+(deftest cursor-atom-behaviors
   (let [test-atom (atom {:a {:b {:c {:d 1}}}})
         test-cursor (r/cursor test-atom [:a :b :c :d])
         witness (atom nil)
@@ -394,3 +382,37 @@
     (is (= (:new @witness) "newer")) ;; shouldn't have changed
     (is (= (running) runs))
     ))
+
+(deftest wrap-atom-behaviors
+  (let [test-atom (atom "foo")
+        test-wrap (r/wrap @test-atom reset! test-atom)
+        witness (atom nil)]
+    ;; per the description, reset! should return the new values
+    (is (= {}
+           (reset! test-wrap {})))
+    (is (= @test-wrap @test-atom))
+
+    ;; per the description, swap! should return the new values
+    (is (= {:z [1 2 3]}
+           (swap! test-wrap assoc :z [1 2 3])))
+    (is (= @test-wrap @test-atom))
+
+    ;; watches should behave like with a normal atom
+    (reset! test-wrap "old")
+    (add-watch test-wrap :w #(reset! witness
+                                     {:key %1 :ref %2 :old %3 :new %4}))
+    (reset! test-wrap "new") ;; this should trigger the watch function
+    (is (= (:key @witness) :w))
+    ;; cursor reports that the reaction is the current atom,
+    ;; but I guess that's ok
+    (is (= (:old @witness) "old"))
+    (is (= (:new @witness) "new"))
+    (is (= (:ref @witness) test-wrap))
+    (is (= (:new @witness) "new"))
+
+    ;; can we remove the watch?
+    (remove-watch test-wrap :w)
+    (reset! test-wrap "removed")
+    (is (= (:new @witness) "new")) ;; shouldn't have changed
+    (is (= @test-wrap @test-atom))
+    ))