inspection view: internalize problem levels for ref and problem nodes

platform/lang-impl/src/com/intellij/codeInspection/ui/InspectionTreeNode.java

@@ -7,7 +7,9 @@ import com.intellij.codeInspection.reference.RefEntity;
 import com.intellij.lang.annotation.HighlightSeverity;
 import com.intellij.openapi.application.ReadAction;
 import com.intellij.openapi.util.AtomicClearableLazyValue;
+import com.intellij.util.containers.Interner;
 import com.intellij.util.ui.tree.TreeUtil;
+import gnu.trove.TObjectHashingStrategy;
 import gnu.trove.TObjectIntHashMap;
 import gnu.trove.TObjectIntProcedure;
 import org.jetbrains.annotations.NotNull;
@@ -25,6 +27,18 @@ import java.util.Enumeration;
  * @author max
  */
 public abstract class InspectionTreeNode extends DefaultMutableTreeNode {
+  private static final Interner<LevelAndCount[]> LEVEL_AND_COUNT_INTERNER = new Interner<>(new TObjectHashingStrategy<LevelAndCount[]>() {
+    @Override
+    public int computeHashCode(LevelAndCount[] object) {
+      return Arrays.hashCode(object);
+    }
+
+    @Override
+    public boolean equals(LevelAndCount[] o1, LevelAndCount[] o2) {
+      return Arrays.equals(o1, o2);
+    }
+  });
+
   protected final AtomicClearableLazyValue<LevelAndCount[]> myProblemLevels = new AtomicClearableLazyValue<LevelAndCount[]>() {
     @NotNull
     @Override
@@ -40,15 +54,21 @@ public abstract class InspectionTreeNode extends DefaultMutableTreeNode {
           return true;
         }
       });
-      Arrays.sort(arr, Comparator.<LevelAndCount, HighlightSeverity>comparing(levelAndCount -> levelAndCount.getLevel().getSeverity()).reversed());
-      return arr;
+      Arrays.sort(arr, Comparator.<LevelAndCount, HighlightSeverity>comparing(levelAndCount -> levelAndCount.getLevel().getSeverity())
+        .reversed());
+      return doesNeedInternProblemLevels() ? LEVEL_AND_COUNT_INTERNER.intern(arr) : arr;
     }
   };
   protected volatile InspectionTreeUpdater myUpdater;
-  protected InspectionTreeNode  (Object userObject) {
+
+  protected InspectionTreeNode(Object userObject) {
     super(userObject);
   }
 
+  protected boolean doesNeedInternProblemLevels() {
+    return false;
+  }
+
   @Nullable
   public Icon getIcon(boolean expanded) {
     return null;
@@ -145,7 +165,7 @@ public abstract class InspectionTreeNode extends DefaultMutableTreeNode {
         }
       }
       int index = TreeUtil.indexedBinarySearch(this, child, InspectionResultsViewComparator.getInstance());
-      if (!allowDuplication && index >= 0){
+      if (!allowDuplication && index >= 0) {
         return (InspectionTreeNode)getChildAt(index);
       }
       insert(child, Math.abs(index + 1));

platform/lang-impl/src/com/intellij/codeInspection/ui/LevelAndCount.java

@@ -1,24 +1,11 @@
-/*
- * Copyright 2000-2017 JetBrains s.r.o.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
+// Copyright 2000-2017 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
 package com.intellij.codeInspection.ui;
 
 import com.intellij.codeHighlighting.HighlightDisplayLevel;
 import org.jetbrains.annotations.NotNull;
 
 class LevelAndCount {
+  @NotNull
   private final HighlightDisplayLevel myLevel;
   private final int myCount;
 
@@ -32,6 +19,26 @@ class LevelAndCount {
     return myLevel;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+
+    LevelAndCount count = (LevelAndCount)o;
+
+    if (myCount != count.myCount) return false;
+    if (myLevel != null ? !myLevel.equals(count.myLevel) : count.myLevel != null) return false;
+
+    return true;
+  }
+
+  @Override
+  public int hashCode() {
+    int result = myLevel != null ? myLevel.hashCode() : 0;
+    result = 31 * result + myCount;
+    return result;
+  }
+
   public int getCount() {
     return myCount;
   }

platform/lang-impl/src/com/intellij/codeInspection/ui/SuppressableInspectionTreeNode.java

@@ -34,6 +34,11 @@ public abstract class SuppressableInspectionTreeNode extends InspectionTreeNode
     myPresentation = presentation;
   }
 
+  @Override
+  protected boolean doesNeedInternProblemLevels() {
+    return true;
+  }
+
   @NotNull
   public InspectionToolPresentation getPresentation() {
     return myPresentation;