From e9fc2e239c877c9c9f217774ffffa1992e0149f5 Mon Sep 17 00:00:00 2001
From: anatoly <tolitius@gmail.com>
Date: Tue, 20 Oct 2015 10:26:35 -0400
Subject: [PATCH] adding ":started?" to avoid double starts

---
 README.md           |  8 ++++----
 dev/dev.clj         |  2 +-
 src/mount/mount.clj | 17 ++++++++++-------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/README.md b/README.md
index 48ff6c3..370e692 100644
--- a/README.md
+++ b/README.md
@@ -101,7 +101,7 @@ this `app-config`, being top level, can be used in other namespaces, including t
 (defstate conn :start (create-connection app-config))
 ```
 
-[here](https://github.com/tolitius/mount/blob/master/test/mount/nyse.clj) 
+[here](https://github.com/tolitius/mount/blob/master/test/app/nyse.clj) 
 is an example of a Datomic connection that "depends" on a similar `app-config`.
 
 ## The Importance of Being Reloadable
@@ -115,7 +115,7 @@ an example.
 
 ## Mount and Develop!
 
-`mount` comes with an example [app](https://github.com/tolitius/mount/blob/master/test/mount/app.clj) 
+`mount` comes with an example [app](https://github.com/tolitius/mount/tree/master/test/app) 
 that has two states:
 
 * `config`, loaded from the files and refreshed on each `(reset)`
@@ -160,9 +160,9 @@ dev=> (reset)
 
 notice that it stopped and started again.
 
-In nyse's connection [:stop](https://github.com/tolitius/mount/blob/a7424d4895ad7abe4933b425e718a6bdf1a0c22f/test/mount/nyse.clj#L18) 
+In nyse's connection [:stop](https://github.com/tolitius/mount/blob/master/test/app/nyse.clj#L18) 
 function database is deleted. Hence after `(reset)` was called the app was brought its starting point: database was created by the
-[:start](https://github.com/tolitius/mount/blob/a7424d4895ad7abe4933b425e718a6bdf1a0c22f/test/mount/nyse.clj#L11) function, 
+[:start](https://github.com/tolitius/mount/blob/master/test/app/nyse.clj#L11) function, 
 but no schema again:
 
 ```clojure
diff --git a/dev/dev.clj b/dev/dev.clj
index 3817f3c..17446c5 100644
--- a/dev/dev.clj
+++ b/dev/dev.clj
@@ -25,7 +25,7 @@
 (defn go
   "Initializes and starts the system running."
   []
-  ;; (refresh) would redefine "defstates" which will call "start" on them
+  (start)
   :ready)
 
 (defn reset
diff --git a/src/mount/mount.clj b/src/mount/mount.clj
index ec909e8..f77f98d 100644
--- a/src/mount/mount.clj
+++ b/src/mount/mount.clj
@@ -11,24 +11,27 @@
 (defmacro defstate [state & body]
   (let [[state [c cf d df]] (macro/name-with-attributes state body)
         {:keys [start stop]} (validate {c cf d df})]
-    (let [s-meta (-> {:state (str `~state) :start `(fn [] (~@start))}
+    (let [s-meta (-> {:state (str `~state) :start `(fn [] (~@start)) :started? true}
                      (cond-> df (assoc :stop `(fn [] (~@stop)))))]
       `(defonce ~(with-meta state (merge (meta state) s-meta))
          (~@start)))))
 
-(defn- up [{:keys [ns name start]}]
-  (intern ns (symbol name) (start)))
+(defn- up [var {:keys [ns name start started?]}]
+  (when-not started?
+    (intern ns (symbol name) (start))
+    (alter-meta! var assoc :started? true)))
 
-(defn- down [{:keys [stop]}]
-  (when stop
-    (stop)))
+(defn- down [var {:keys [stop started?]}]
+  (when started?
+    (alter-meta! var assoc :started? false)
+    (when stop (stop))))
 
 (defn- f-states [f]
   (->> (all-ns)
        (mapcat ns-interns)
        (map second)
        (filter #(:state (meta %)))
-       (map (comp f meta))))
+       (map #(f % (meta %)))))
 
 (defn start []
   (doall