Move findFirst in FutureUtils and use AtomicInteger instead of synchronized

Author: jad-hamza

src/main/scala/inox/solvers/combinators/PortfolioSolver.scala

@@ -58,7 +58,7 @@ trait PortfolioSolver extends Solver { self =>
       }
     }
 
-    inox.utils.findFirst(fs)(_._2 != Unknown) match {
+    inox.utils.FutureUtils.findFirst(fs)(_._2 != Unknown) match {
       case Some((s, r)) =>
         resultSolver = s.getResultSolver
         resultSolver.foreach { solv =>

src/main/scala/inox/utils/FutureUtils.scala

@@ -0,0 +1,30 @@
+/* Copyright 2009-2021 EPFL, Lausanne */
+
+package inox.utils
+
+import scala.util._
+import scala.concurrent._
+import scala.concurrent.duration._
+import scala.concurrent.ExecutionContext.Implicits.global
+import java.util.concurrent.atomic.AtomicInteger
+
+object FutureUtils {
+
+  def findFirst[T](futures: Seq[Future[T]])(cond: T => Boolean): Option[T] = {
+    val p = Promise[Option[T]]()
+    val n = futures.length
+    val i = new AtomicInteger(0)
+
+    for (future <- futures) {
+      future.onComplete((result: Try[T]) => result match {
+        case Success(res) if cond(res) =>
+          p.trySuccess(Some(res))
+        case _ =>
+          synchronized { i.getAndIncrement() }
+          if (i.get == n) p.trySuccess(None)
+      })
+    }
+    Await.result(p.future, Duration.Inf)
+  }
+
+}

src/main/scala/inox/utils/package.scala

@@ -2,11 +2,6 @@
 
 package inox
 
-import scala.util._
-import scala.concurrent._
-import scala.concurrent.duration._
-import scala.concurrent.ExecutionContext.Implicits.global
-
 /** Various utilities used throughout the Inox system */
 package object utils {
 
@@ -31,22 +26,5 @@ package object utils {
     }
     v2
   }
-
-  def findFirst[T](futures: Seq[Future[T]])(cond: T => Boolean): Option[T] = {
-    val p = Promise[Option[T]]()
-    val n = futures.length
-    var i = 0
-
-    for (future <- futures) {
-      future.onComplete((result: Try[T]) => result match {
-        case Success(res) if cond(res) =>
-          p.trySuccess(Some(res))
-        case _ =>
-          synchronized { i += 1 }
-          if (i == n) p.trySuccess(None)
-      })
-    }
-    Await.result(p.future, Duration.Inf)
-  }
-
+  
 }