add polling functions

dev/user.clj

@@ -10,6 +10,7 @@
     [kria.conversions :as conv]
     [kria.core :as core]
     [kria.index :as index]
+    [kria.polling :as p]
     [kria.object :as object]
     [kria.schema :as schema]
     [kria.search :as search]

test/kria/polling.clj

@@ -0,0 +1,28 @@
+(ns kria.polling)
+
+(set! *warn-on-reflection* true)
+
+(defn poll
+  "Returns true if function `f` returns value `v` within `max-i`
+  iterations. Returns false otherwise. Each iteration waits `i-delay`
+  milliseconds."
+  [v f max-i i-delay]
+  (loop [i 0]
+    (if (>= i max-i)
+      false
+      (let [fv (f)]
+        (if (= v fv)
+          true
+          (do
+            (Thread/sleep i-delay)
+            (recur (inc i))))))))
+
+(defn poll+
+  "Returns true if `poll` function returns true and predicate
+  function remains true after an additional time delay. This is
+  intended to confirm that the function does not change after
+  becoming true."
+  [v f max-i i-delay]
+  (when (poll v f max-i i-delay)
+    (Thread/sleep (* 2 i-delay))
+    (= v (f))))