get-key-blocking accepts optional interval/timeout

This is implemented by a shared function block-on in lanterna.common.

Author: zachallaun

src/lanterna/common.clj

@@ -10,3 +10,23 @@
         (.getCharacter k)
         kind))))
 
+(defn block-on
+  "Repeatedly apply func to args until a non-nil value is returned.
+
+  opts is a map optionally containing an :interval and a :timeout in msecs.
+    :interval sets the interval between function applications (default 50).
+    :timeout sets the maximum amount of time blocking will occur before
+    returning nil.
+
+  "
+  [func args {:keys [interval timeout] :as opts}]
+  (let [{:keys [interval timeout]} (merge {:interval 50
+                                           :timeout Double/POSITIVE_INFINITY}
+                                          opts)]
+    (loop [timeout timeout]
+      (when (> timeout 0)
+        (let [val (apply func args)]
+          (if (nil? val)
+            (do (Thread/sleep interval)
+                (recur (- timeout interval)))
+            val))))))

src/lanterna/screen.clj

@@ -1,7 +1,7 @@
 (ns lanterna.screen
   (:import com.googlecode.lanterna.screen.Screen
            com.googlecode.lanterna.terminal.Terminal)
-  (:use [lanterna.common :only [parse-key]])
+  (:use [lanterna.common :only [parse-key block-on]])
   (:require [lanterna.constants :as c]
             [lanterna.terminal :as t]))
 
@@ -275,17 +275,14 @@
   If the user has *not* pressed a key, this function will block, checking every
   50ms.  If you want to return nil immediately, use get-key instead.
 
-  TODO: Make the interval configurable.
-  TODO: Add a timeout option.
+  Optionally accepts :interval and :timeout &rest keyword arguments.
+    :interval sets the interval between checks.
+    :timeout sets the maximum amount of time blocking will occur before
+    returning nil.
 
   "
-  [^Screen screen]
-  (let [k (get-key screen)]
-    (if (nil? k)
-      (do
-        (Thread/sleep 50)
-        (recur screen))
-      k)))
+  [^Screen screen & {:keys [interval timeout] :as opts}]
+  (block-on get-key [screen] opts))
 
 
 (comment

src/lanterna/terminal.clj

@@ -6,7 +6,7 @@
            com.googlecode.lanterna.terminal.swing.TerminalPalette
            java.awt.GraphicsEnvironment
            java.awt.Font)
-  (:use [lanterna.common :only [parse-key]])
+  (:use [lanterna.common :only [parse-key block-on]])
   (:require [lanterna.constants :as c]))
 
 
@@ -240,17 +240,14 @@
   If the user has *not* pressed a key, this function will block, checking every
   50ms.  If you want to return nil immediately, use get-key instead.
 
-  TODO: Make the interval configurable.
-  TODO: Add a timeout option.
+  Optionally accepts :interval and :timeout &rest keyword arguments.
+    :interval sets the interval between checks.
+    :timeout sets the maximum amount of time blocking will occur before
+    returning nil.
 
   "
-  [^Terminal terminal]
-  (let [k (get-key terminal)]
-    (if (nil? k)
-      (do
-        (Thread/sleep 50)
-        (recur terminal))
-      k)))
+  [^Terminal terminal & {:keys [interval timeout] :as opts}]
+  (block-on get-key [terminal] opts))
 
 
 (comment
@@ -263,6 +260,8 @@
   (start t)
   (set-fg-color t :yellow)
   (put-string t "Hello, world!")
+  (get-key-blocking t :timeout 1000)
+  (get-key-blocking t :interval 2000)
   (stop t)
 
   )