Make Timer safe on multiple clears

core/src/main/scala/scala/scalanative/loop/Timer.scala

@@ -7,7 +7,7 @@ import LibUV._, LibUVConstants._
 import scala.scalanative.unsafe.Ptr
 import internals.HandleUtils
 
-@inline class Timer private (private val ptr: Ptr[Byte]) extends AnyVal {
+@inline final class Timer private (private val ptr: Ptr[Byte]) extends AnyVal {
   def clear(): Unit = {
     uv_timer_stop(ptr)
     HandleUtils.close(ptr)
@@ -37,21 +37,30 @@ object Timer {
     val timerHandle = stdlib.malloc(uv_handle_size(UV_TIMER_T))
     uv_timer_init(EventLoop.loop, timerHandle)
     HandleUtils.setData(timerHandle, callback)
+    val timer = new Timer(timerHandle)
+    val withClearIfTimeout: () => Unit =
+      if (repeat == 0L) { () =>
+        {
+          callback()
+          timer.clear()
+        }
+      } else callback
     uv_timer_start(timerHandle, timeoutCB, timeout, repeat)
-    new Timer(timerHandle)
+    timer
   }
 
   def delay(duration: FiniteDuration): Future[Unit] = {
     val promise = Promise[Unit]()
-    timeout(duration.toMillis)(() => promise.success(()))
+    timeout(duration)(() => promise.success(()))
     promise.future
   }
 
-  def timeout(millis: Long)(callback: () => Unit): Timer = {
-    startTimer(millis, 0L, callback)
+  def timeout(duration: FiniteDuration)(callback: () => Unit): Timer = {
+    startTimer(duration.toMillis, 0L, callback)
   }
 
-  def repeat(millis: Long)(callback: () => Unit): Timer = {
+  def repeat(duration: FiniteDuration)(callback: () => Unit): Timer = {
+    val millis = duration.toMillis
     startTimer(millis, millis, callback)
   }
 }

core/src/main/scala/scala/scalanative/loop/internals/HandleUtils.scala

@@ -14,28 +14,38 @@ private[loop] object HandleUtils {
   @inline def getData[T <: Object](handle: Ptr[Byte]): T = {
     // data is the first member of uv_loop_t
     val ptrOfPtr = handle.asInstanceOf[Ptr[Ptr[Byte]]]
-    val rawptr = toRawPtr(!ptrOfPtr)
-    castRawPtrToObject(rawptr).asInstanceOf[T]
+    val dataPtr = !ptrOfPtr
+    if (dataPtr == null) null.asInstanceOf[T]
+    else {
+      val rawptr = toRawPtr(dataPtr)
+      castRawPtrToObject(rawptr).asInstanceOf[T]
+    }
   }
   @inline def setData(handle: Ptr[Byte], obj: Object): Unit = {
-    if (references.contains(obj)) references(obj) += 1
-    else references(obj) = 1
-
     // data is the first member of uv_loop_t
     val ptrOfPtr = handle.asInstanceOf[Ptr[Ptr[Byte]]]
-    val rawptr = castObjectToRawPtr(obj)
-    !ptrOfPtr = fromRawPtr[Byte](rawptr)
+    if(obj != null) {
+      if (references.contains(obj)) references(obj) += 1
+      else references(obj) = 1
+      val rawptr = castObjectToRawPtr(obj)
+      !ptrOfPtr = fromRawPtr[Byte](rawptr)
+    } else {
+      !ptrOfPtr = null
+    }
   }
   private val onCloseCB = new CloseCB {
     def apply(handle: UVHandle): Unit = {
       stdlib.free(handle)
     }
   }
   @inline def close(handle: Ptr[Byte]): Unit = {
-    uv_close(handle, onCloseCB)
-    val data    = getData[Object](handle)
-    val current = references(data)
-    if (current > 1) references(data) -= 1
-    else references.remove(data)
+    if(getData(handle) != null) {
+      uv_close(handle, onCloseCB)
+      val data    = getData[Object](handle)
+      val current = references(data)
+      if (current > 1) references(data) -= 1
+      else references.remove(data)
+      setData(handle, null)
+    }
   }
 }

core/src/test/scala/scala/scalanative/loop/TimerTests.scala

@@ -30,7 +30,7 @@ object TimerTests extends LoopTestSuite {
       val times        = 3
       val p            = Promise[Unit]()
       var timer: Timer = null.asInstanceOf[Timer]
-      timer = Timer.repeat(d.toMillis) { () =>
+      timer = Timer.repeat(d) { () =>
         if (i == times) {
           p.success(())
           timer.clear()
@@ -43,13 +43,23 @@ object TimerTests extends LoopTestSuite {
       }
     }
     test("clear timeout") {
-      val handle = Timer.timeout(d.toMillis) { () =>
+      val handle = Timer.timeout(d) { () =>
         throw new Exception("This timeout should have not triggered")
       }
       handle.clear()
       for {
         () <- Timer.delay(d * 2)
       } yield ()
     }
+    test("close multiple times") {
+      val timer = Timer.timeout(10.millis)(() => {})
+      timer.clear()
+      timer.clear()
+      global.execute(new Runnable { def run(): Unit = timer.clear() })
+      Timer.timeout(50.millis) { () =>
+        timer.clear()
+        timer.clear()
+      }
+    }
   }
 }