From 2eee695e92f7f7ef6a9e9e8b9929681850e64cab Mon Sep 17 00:00:00 2001
From: Martin Kavalar <martin@nextjournal.com>
Date: Thu, 31 Oct 2024 11:02:51 -0700
Subject: [PATCH] Support interrupting (recursive) function call

---
 src/sci/impl/fns.cljc   |  4 ++++
 test/sci/core_test.cljc | 17 ++++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/src/sci/impl/fns.cljc b/src/sci/impl/fns.cljc
index 46403273..cb471c95 100644
--- a/src/sci/impl/fns.cljc
+++ b/src/sci/impl/fns.cljc
@@ -24,6 +24,8 @@
             ~@(when varargs
                 [`(aset ~'invoc-array ~'vararg-idx ~varargs-param)])
             (loop []
+              #?(:clj (when (java.lang.Thread/.isInterrupted (Thread/currentThread))
+                        (throw (java.lang.InterruptedException.))))
               (let [ret# (types/eval ~'body ~'ctx ~'invoc-array)]
                 (if (kw-identical? :sci.impl.analyzer/recur ret#)
                   (recur)
@@ -44,6 +46,8 @@
             ~@(when varargs
                 [`(aset ~'invoc-array ~'vararg-idx ~varargs-param)])
             (loop []
+              #?(:clj (when (java.lang.Thread/.isInterrupted (Thread/currentThread))
+                        (throw (java.lang.InterruptedException.))))
               (let [ret# (types/eval ~'body ~'ctx ~'invoc-array)]
                 (if (kw-identical? :sci.impl.analyzer/recur ret#)
                   (recur)
diff --git a/test/sci/core_test.cljc b/test/sci/core_test.cljc
index c0d0226e..341a5a1c 100644
--- a/test/sci/core_test.cljc
+++ b/test/sci/core_test.cljc
@@ -1703,15 +1703,30 @@
      (is (true? (sci/eval-string "(exists? js/console.log)" {:classes {'js js/globalThis
                                                                        :allow :all}})))
      (is (false? (sci/eval-string "(exists? js/foo.bar)" {:classes {'js js/globalThis
-                                                                               :allow :all}})))
+                                                                    :allow :all}})))
      (is (false? (sci/eval-string "(exists? js/console.log.foobar)" {:classes {'js js/globalThis
                                                                                :allow :all}})))
      (is (false? (sci/eval-string "(exists? console.log)" {:classes {'js js/globalThis
                                                                      :allow :all}})))))
 
+#?(:clj
+   (deftest interrupt-test
+     (testing "check that long-running recursive function can be interrupted")
+     (let [thread (Thread. (fn []
+                             (time
+                              (sci/eval-form
+                               (sci/init {})
+                               '((fn a [n] (if (#{0 1} n) 1 (+ (a (- n 2)) (a (- n 1)))))  35)))))]
+       (.start thread)
+       (is (= java.lang.Thread$State/RUNNABLE (.getState thread)))
+       (.interrupt thread)
+       (Thread/sleep 1)
+       (is (= java.lang.Thread$State/TERMINATED (.getState thread))))))
+
 ;;;; Scratch
 
 (comment
   (eval* 1 '(inc *in*))
   (test-difference "foo" "[10 10]" 0 10)
   (test-difference "rand" #(rand) 0 10))
+