From 135c418cadef7180d285fec74d85edcf1809ccb1 Mon Sep 17 00:00:00 2001
From: Alexey Kudravtsev <cdr@intellij.com>
Date: Thu, 26 May 2016 12:25:40 +0300
Subject: [PATCH] performance in case of thousands events in the queue should
 be linear, not quadratic

---
 .../src/com/intellij/ide/IdeEventQueue.java   | 98 +++++++++++--------
 .../com/intellij/ide/IdeEventQueueTest.java   | 40 ++++++++
 2 files changed, 95 insertions(+), 43 deletions(-)
 create mode 100644 platform/platform-tests/testSrc/com/intellij/ide/IdeEventQueueTest.java

diff --git a/platform/platform-impl/src/com/intellij/ide/IdeEventQueue.java b/platform/platform-impl/src/com/intellij/ide/IdeEventQueue.java
index 1fce159d8d2b..049a2dbda779 100644
--- a/platform/platform-impl/src/com/intellij/ide/IdeEventQueue.java
+++ b/platform/platform-impl/src/com/intellij/ide/IdeEventQueue.java
@@ -123,6 +123,7 @@ public class IdeEventQueue extends EventQueue {
    * Swing event.
    */
   private int myEventCount;
+  private int myKeyboardEventsInTheQueue; // accessed in EDT only
 
   private boolean myIsInInputEvent;
 
@@ -356,50 +357,57 @@ public class IdeEventQueue extends EventQueue {
 
   @Override
   public void dispatchEvent(@NotNull AWTEvent e) {
-    if (!appIsLoaded()) {
-      try {
-        super.dispatchEvent(e);
+    try {
+      if (!appIsLoaded()) {
+        try {
+          super.dispatchEvent(e);
+        }
+        catch (Throwable t) {
+          processException(t);
+        }
+        return;
+      }
+
+      e = InertialMouseRouter.changeSourceIfNeeded(e);
+
+      e = fixNonEnglishKeyboardLayouts(e);
+
+      e = mapEvent(e);
+      if (Registry.is("keymap.windows.as.meta")) {
+        e = mapMetaState(e);
+      }
+
+      boolean wasInputEvent = myIsInInputEvent;
+      myIsInInputEvent = e instanceof InputEvent || e instanceof InputMethodEvent || e instanceof WindowEvent || e instanceof ActionEvent;
+      if (myIsInInputEvent) {
+        HeavyProcessLatch.INSTANCE.prioritizeUiActivity();
+      }
+      AWTEvent oldEvent = myCurrentEvent;
+      myCurrentEvent = e;
+
+      boolean userActivity = myIsInInputEvent || e instanceof ItemEvent;
+      try (AccessToken ignored = startActivity(userActivity)) {
+        _dispatchEvent(e, false);
       }
       catch (Throwable t) {
         processException(t);
       }
-      return;
-    }
+      finally {
+        myIsInInputEvent = wasInputEvent;
+        myCurrentEvent = oldEvent;
 
-    e = InertialMouseRouter.changeSourceIfNeeded(e);
+        for (EventDispatcher each : myPostProcessors) {
+          each.dispatch(e);
+        }
 
-    e = fixNonEnglishKeyboardLayouts(e);
-
-    e = mapEvent(e);
-    if (Registry.is("keymap.windows.as.meta")) {
-      e = mapMetaState(e);
-    }
-
-    boolean wasInputEvent = myIsInInputEvent;
-    myIsInInputEvent = e instanceof InputEvent || e instanceof InputMethodEvent || e instanceof WindowEvent || e instanceof ActionEvent;
-    if (myIsInInputEvent) {
-      HeavyProcessLatch.INSTANCE.prioritizeUiActivity();
-    }
-    AWTEvent oldEvent = myCurrentEvent;
-    myCurrentEvent = e;
-
-    boolean userActivity = myIsInInputEvent || e instanceof ItemEvent;
-    try (AccessToken ignored = startActivity(userActivity)) {
-      _dispatchEvent(e, false);
-    }
-    catch (Throwable t) {
-      processException(t);
+        if (e instanceof KeyEvent) {
+          maybeReady();
+        }
+      }
     }
     finally {
-      myIsInInputEvent = wasInputEvent;
-      myCurrentEvent = oldEvent;
-
-      for (EventDispatcher each : myPostProcessors) {
-        each.dispatch(e);
-      }
-
-      if (e instanceof KeyEvent) {
-        maybeReady();
+      if (isKeyboardEvent(e)) {
+        myKeyboardEventsInTheQueue--;
       }
     }
   }
@@ -586,10 +594,7 @@ public class IdeEventQueue extends EventQueue {
       enterSuspendModeIfNeeded(e);
     }
 
-    myKeyboardBusy = e instanceof KeyEvent ||
-                     peekEvent(KeyEvent.KEY_PRESSED) != null ||
-                     peekEvent(KeyEvent.KEY_RELEASED) != null ||
-                     peekEvent(KeyEvent.KEY_TYPED) != null;
+    myKeyboardBusy = myKeyboardEventsInTheQueue != 0;
 
     if (e instanceof KeyEvent) {
       if (e.getID() == KeyEvent.KEY_RELEASED && ((KeyEvent)e).getKeyCode() == KeyEvent.VK_SHIFT) {
@@ -1150,9 +1155,16 @@ public class IdeEventQueue extends EventQueue {
 
   private final FrequentEventDetector myFrequentEventDetector = new FrequentEventDetector(1009, 100);
   @Override
-  public void postEvent(@NotNull AWTEvent theEvent) {
-    myFrequentEventDetector.eventHappened(theEvent);
-    super.postEvent(theEvent);
+  public void postEvent(@NotNull AWTEvent event) {
+    myFrequentEventDetector.eventHappened(event);
+    if (isKeyboardEvent(event)) {
+      myKeyboardEventsInTheQueue++;
+    }
+    super.postEvent(event);
+  }
+
+  private static boolean isKeyboardEvent(@NotNull AWTEvent event) {
+    return event instanceof KeyEvent && (event.getID() == KeyEvent.KEY_PRESSED || event.getID() == KeyEvent.KEY_RELEASED || event.getID() == KeyEvent.KEY_TYPED);
   }
 
   @Override
diff --git a/platform/platform-tests/testSrc/com/intellij/ide/IdeEventQueueTest.java b/platform/platform-tests/testSrc/com/intellij/ide/IdeEventQueueTest.java
new file mode 100644
index 000000000000..39ba20e0703c
--- /dev/null
+++ b/platform/platform-tests/testSrc/com/intellij/ide/IdeEventQueueTest.java
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2000-2016 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.
+ */
+package com.intellij.ide;
+
+import com.intellij.testFramework.PlatformTestCase;
+import com.intellij.testFramework.PlatformTestUtil;
+import com.intellij.util.ui.UIUtil;
+
+import javax.swing.*;
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class IdeEventQueueTest extends PlatformTestCase {
+  public void testManyEvents() {
+    int N = 100000;
+    PlatformTestUtil.startPerformanceTest("Event queue dispatch", 10000, () -> {
+      AtomicInteger count = new AtomicInteger();
+      UIUtil.dispatchAllInvocationEvents();
+      for (int i=0;i<N;i++) {
+        SwingUtilities.invokeLater(() -> {
+          count.incrementAndGet();
+        });
+      }
+      UIUtil.dispatchAllInvocationEvents();
+      assertEquals(N, count.get());
+    }).assertTiming();
+  }
+}