reduce debugger views flickering - process all events with delay

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XDebugView.java

@@ -20,7 +20,7 @@ import com.intellij.ide.DataManager;
 import com.intellij.openapi.Disposable;
 import com.intellij.openapi.actionSystem.DataContext;
 import com.intellij.ui.content.ContentManager;
-import com.intellij.util.SingleAlarm;
+import com.intellij.util.Alarm;
 import com.intellij.xdebugger.XDebugSession;
 import com.intellij.xdebugger.impl.ui.XDebugSessionTab;
 import org.jetbrains.annotations.NotNull;
@@ -35,29 +35,26 @@ import java.util.EventObject;
 public abstract class XDebugView implements Disposable {
   public enum SessionEvent {PAUSED, BEFORE_RESUME, RESUMED, STOPPED, FRAME_CHANGED, SETTINGS_CHANGED}
 
-  private final SingleAlarm myClearAlarm;
-  private static final int VIEW_CLEAR_DELAY = 100; //ms
+  private final Alarm myUpdateAlarm;
+  private static final int VIEW_UPDATE_DELAY = 100; //ms
 
   public XDebugView() {
-    myClearAlarm = new SingleAlarm(new Runnable() {
-      @Override
-      public void run() {
-        clear();
-      }
-    }, VIEW_CLEAR_DELAY, this);
-  }
-
-  protected final void requestClear() {
-    myClearAlarm.cancelAndRequest();
-  }
-
-  protected final void cancelClear() {
-    myClearAlarm.cancel();
+    myUpdateAlarm = new Alarm(this);
   }
 
   protected abstract void clear();
 
-  public abstract void processSessionEvent(@NotNull SessionEvent event);
+  public void onSessionEvent(@NotNull final SessionEvent event) {
+    myUpdateAlarm.cancelAllRequests();
+    myUpdateAlarm.addRequest(new Runnable() {
+      @Override
+      public void run() {
+        processSessionEvent(event);
+      }
+    }, VIEW_UPDATE_DELAY);
+  }
+
+  protected abstract void processSessionEvent(@NotNull SessionEvent event);
 
   @Nullable
   protected static XDebugSession getSession(@NotNull EventObject e) {

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XDebugViewSessionListener.java

@@ -36,7 +36,7 @@ public class XDebugViewSessionListener extends XDebugSessionAdapter {
     AppUIUtil.invokeLaterIfProjectAlive(session.getProject(), new Runnable() {
       @Override
       public void run() {
-        myDebugView.processSessionEvent(event);
+        myDebugView.onSessionEvent(event);
       }
     });
   }

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XFramesView.java

@@ -221,13 +221,11 @@ public class XFramesView extends XDebugView {
     mySelectedStack = null;
     XSuspendContext suspendContext = session == null ? null : session.getSuspendContext();
     if (suspendContext == null) {
-      requestClear();
+      clear();
       return;
     }
 
     if (event == SessionEvent.PAUSED) {
-      // clear immediately
-      cancelClear();
       clear();
     }
 

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XVariablesView.java

@@ -57,11 +57,10 @@ public class XVariablesView extends XVariablesViewBase {
 
     tree.markNodesObsolete();
     if (stackFrame != null) {
-      cancelClear();
       buildTreeAndRestoreState(stackFrame);
     }
     else {
-      requestClear();
+      clear();
     }
   }
 

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/frame/XWatchesViewImpl.java

@@ -275,7 +275,6 @@ public class XWatchesViewImpl extends XDebugView implements DnDNativeTarget, XWa
     XDebugSession session = getSession(getMainPanel());
     XStackFrame stackFrame = session == null ? null : session.getCurrentStackFrame();
     if (stackFrame != null) {
-      cancelClear();
       tree.setSourcePosition(stackFrame.getSourcePosition());
       myRootNode.updateWatches(stackFrame.getEvaluator());
       if (myTreeState != null) {
@@ -283,7 +282,7 @@ public class XWatchesViewImpl extends XDebugView implements DnDNativeTarget, XWa
       }
     }
     else {
-      requestClear();
+      clear();
     }
   }
 

platform/xdebugger-impl/src/com/intellij/xdebugger/impl/ui/XDebugSessionTab.java

@@ -198,7 +198,7 @@ public class XDebugSessionTab extends DebuggerSessionTabBase {
       @Override
       public void run() {
         for (XDebugView view : myViews) {
-          view.processSessionEvent(XDebugView.SessionEvent.SETTINGS_CHANGED);
+          view.onSessionEvent(XDebugView.SessionEvent.SETTINGS_CHANGED);
         }
       }
     });