[vcs-log-graph] convert BfsUtil to kotlin

platform/vcs-log/graph/src/com/intellij/vcs/log/graph/utils/BfsUtil.kt

@@ -13,59 +13,55 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package com.intellij.vcs.log.graph.utils;
+package com.intellij.vcs.log.graph.utils
 
-import com.intellij.util.containers.ContainerUtil;
-import com.intellij.vcs.log.graph.api.LiteLinearGraph;
-import org.jetbrains.annotations.NotNull;
+import com.intellij.util.containers.ContainerUtil
+import com.intellij.vcs.log.graph.api.LiteLinearGraph
+import java.util.*
 
-import java.util.ArrayList;
-import java.util.List;
-import java.util.Queue;
+object BfsUtil {
+  fun getCorrespondingParent(graph: LiteLinearGraph, startNode: Int, endNode: Int, visited: Flags): Int {
+    val candidates = graph.getNodes(startNode, LiteLinearGraph.NodeFilter.DOWN)
+    if (candidates.size == 1) return candidates[0]
+    if (candidates.contains(endNode)) return endNode
 
-public class BfsUtil {
-  public static int getCorrespondingParent(@NotNull LiteLinearGraph graph, int startNode, int endNode, @NotNull Flags visited) {
-    List<Integer> candidates = graph.getNodes(startNode, LiteLinearGraph.NodeFilter.DOWN);
-    if (candidates.size() == 1) return candidates.get(0);
-    if (candidates.contains(endNode)) return endNode;
-
-    List<Queue<Integer>> queues = new ArrayList<>(candidates.size());
-    for (int candidate : candidates) {
-      queues.add(ContainerUtil.newLinkedList(candidate));
+    val queues = ArrayList<Queue<Int>>(candidates.size)
+    for (candidate in candidates) {
+      queues.add(ContainerUtil.newLinkedList(candidate))
     }
 
-    int emptyCount;
-    visited.setAll(false);
+    var emptyCount: Int
+    visited.setAll(false)
     do {
-      emptyCount = 0;
-      for (Queue<Integer> queue : queues) {
+      emptyCount = 0
+      for (queue in queues) {
         if (queue.isEmpty()) {
-          emptyCount++;
+          emptyCount++
         }
         else {
-          boolean found = runNextBfsStep(graph, queue, visited, endNode);
+          val found = runNextBfsStep(graph, queue, visited, endNode)
           if (found) {
-            return candidates.get(queues.indexOf(queue));
+            return candidates[queues.indexOf(queue)]
           }
         }
       }
     }
-    while (emptyCount < queues.size());
+    while (emptyCount < queues.size)
 
-    return candidates.get(0);
+    return candidates[0]
   }
 
-  private static boolean runNextBfsStep(@NotNull LiteLinearGraph graph, @NotNull Queue<Integer> queue, @NotNull Flags visited, int target) {
+  private fun runNextBfsStep(graph: LiteLinearGraph, queue: Queue<Int>, visited: Flags, target: Int): Boolean {
     while (!queue.isEmpty()) {
-      Integer node = queue.poll();
-      if (!visited.get(node)) {
-        visited.set(node, true);
-        List<Integer> next = graph.getNodes(node, LiteLinearGraph.NodeFilter.DOWN);
-        if (next.contains(target)) return true;
-        queue.addAll(next);
-        return false;
+      val node = queue.poll()
+      if (!visited.get(node!!)) {
+        visited.set(node, true)
+        val next = graph.getNodes(node, LiteLinearGraph.NodeFilter.DOWN)
+        if (next.contains(target)) return true
+        queue.addAll(next)
+        return false
       }
     }
-    return false;
+    return false
   }
 }