add function to call a function with a timeout

src/clj/clj_rhino.clj

@@ -145,6 +145,14 @@
       (.evaluateString ctx scope code filename line-number sec-domain)
       (finally (Context/exit)))))
 
+(defn call-timeout [scope fun timeout-ms & args]
+  (let [factory (TimedContextFactory. timeout-ms)
+        ctx (.enterContext factory)
+        args (into-array Object (map #(to-js % scope ctx) args))]
+    (try
+      (.call fun ctx scope nil args)
+      (finally (Context/exit)))))
+
 (defn undefined? [value]
   "return true if value is undefined"
   (= value (. UniqueTag NOT_FOUND)))
@@ -225,10 +233,12 @@
   "create a new scope using a safe root scope as parent"
   (new-scope ctx (new-safe-root-scope ctx)))
 
-(defn compile-function [scope code & {:keys [ctx filename line-number sec-domain]}]
+(defn compile-function [scope code & {:keys [filename line-number sec-domain]}]
   "compile and return function defined in code"
-  (with-context-if-nil ctx (fn [ctx]
-                             (.compileFunction ctx scope code 
-                                              (or filename "<eval>")
-                                              (or line-number 1) sec-domain))))
+  (let [ctx (.enterContext (TimedContextFactory. 0))]
+    (try
+      (.compileFunction ctx scope code 
+                        (or filename "<eval>")
+                        (or line-number 1) sec-domain)
+      (finally (Context/exit)))))
 

src/java/org/marianoguerra/rhino/TimeOutError.java

@@ -0,0 +1,9 @@
+package org.marianoguerra.rhino;
+
+public class TimeOutError extends Error {
+	public final long timeoutMillis;
+
+	public TimeOutError(long timeoutMillis) {
+		this.timeoutMillis = timeoutMillis;
+	}
+}

src/java/org/marianoguerra/rhino/TimedContextFactory.java

@@ -44,7 +44,7 @@ public class TimedContextFactory extends ContextFactory {
 			// it is time to stop the script.
 			// Throw Error instance to ensure that script will never
 			// get control back through catch or finally.
-			throw new Error();
+			throw new TimeOutError(this.timeoutMillis);
 		}
 	}
 

test/clj_rhino/core_test.clj

@@ -1,5 +1,6 @@
 (ns clj-rhino.core-test
-  (:import [org.mozilla.javascript Context UniqueTag EvaluatorException NativeArray])
+  (:import [org.mozilla.javascript Context UniqueTag EvaluatorException NativeArray]
+           [org.marianoguerra.rhino TimeOutError])
   (:use clojure.test)
   (:require [clj-rhino :as js]))
 
@@ -197,7 +198,26 @@
 
   (testing "eval-timeout times out on infinite loop"
            (let [scope (js/new-safe-scope)]
-             (is (thrown? Error (js/eval-timeout scope "while (true);" 1000)))))
+             (is (thrown? TimeOutError (js/eval-timeout scope "while (true);" 1000)))))
+
+  (testing "call-timeout works"
+           (let [scope (js/new-safe-scope)
+                 fun-code "function (a, b) { return a + b; }"
+                 compiled-fun (js/compile-function scope fun-code)
+                 result (js/call-timeout scope compiled-fun 1000 2 3)]
+
+             (is (= result 5.0))))
+
+  (testing "call-timeout timeouts correctly"
+           (let [scope (js/new-safe-scope)
+                 fun-code "function (a, b) { while(true); }"
+                 compiled-fun (js/compile-function scope fun-code)]
+
+             (try
+               (js/call-timeout scope compiled-fun 1000 2 3)
+               (throw (Exception. "shouldn't reach this point, should timeout"))
+               (catch TimeOutError error
+                 (is (= (.-timeoutMillis error) 1000))))))
 
   (testing "native clojure functions can be added"
            (js/with-context