Merge remote-tracking branch 'origin/master'

2026-09-27 10:03:11 +07:00 · 2015-05-18 20:33:37 +03:00
parent d3faa371a6 cdc1c4eaf2
commit 6e9abc6e7b
8 changed files with 401 additions and 299 deletions
@@ -24,10 +24,10 @@ import com.intellij.diff.contents.FileContent;
 import com.intellij.diff.requests.ContentDiffRequest;
 import com.intellij.diff.requests.DiffRequest;
 import com.intellij.diff.tools.util.DiffNotifications;
+import com.intellij.diff.tools.util.FocusTrackerSupport;
 import com.intellij.diff.tools.util.SimpleDiffPanel;
 import com.intellij.diff.tools.util.StatusPanel;
 import com.intellij.diff.tools.util.base.ListenerDiffViewerBase;
-import com.intellij.diff.util.DiffUserDataKeys;
 import com.intellij.diff.util.DiffUtil;
 import com.intellij.diff.util.Side;
 import com.intellij.openapi.Disposable;
@@ -61,8 +61,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;

 import javax.swing.*;
-import java.awt.event.FocusAdapter;
-import java.awt.event.FocusEvent;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.List;
@@ -79,10 +77,7 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  @Nullable private final FileEditorProvider myEditorProvider1;
  @Nullable private final FileEditorProvider myEditorProvider2;

-  @Nullable private final MyEditorFocusListener myEditorFocusListener1;
-  @Nullable private final MyEditorFocusListener myEditorFocusListener2;
-
-  @NotNull private Side myCurrentSide = Side.LEFT;
+  @NotNull private final FocusTrackerSupport.TwosideFocusTrackerSupport myFocusTrackerSupport;

  public BinaryDiffViewer(@NotNull DiffContext context, @NotNull DiffRequest request) {
    super(context, (ContentDiffRequest)request);
@@ -96,32 +91,18 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
    myEditorProvider2 = editors.second.second;
    assert myEditor1 != null || myEditor2 != null;

-    if (myEditor1 != null && myEditor2 != null) {
-      myEditorFocusListener1 = new MyEditorFocusListener(Side.LEFT);
-      myEditorFocusListener2 = new MyEditorFocusListener(Side.RIGHT);
-    }
-    else {
-      myEditorFocusListener1 = null;
-      myEditorFocusListener2 = null;
-    }
-
-
-    myContentPanel = new BinaryContentPanel(titlePanel, myEditor1, myEditor2);
+    myFocusTrackerSupport = new FocusTrackerSupport.TwosideFocusTrackerSupport(getEditor1(), getEditor2());
+    myContentPanel = new BinaryContentPanel(titlePanel, getEditor1(), getEditor2());

    myPanel = new SimpleDiffPanel(myContentPanel, this, context);

    myStatusPanel = new MyStatusPanel();

    new MyFocusOppositePaneAction().setupAction(myPanel);
-
-
-    installEditorListeners();
  }

-  @Override
  @CalledInAwt
  public void onDispose() {
-    destroyEditorListeners();
    destroyEditors();
    super.onDispose();
  }
@@ -130,25 +111,14 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  @CalledInAwt
  protected void processContextHints() {
    super.processContextHints();
-    if (myEditor1 == null) {
-      myCurrentSide = Side.RIGHT;
-    }
-    else if (myEditor2 == null) {
-      myCurrentSide = Side.LEFT;
-    }
-    else {
-      Side side = myContext.getUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE);
-      if (side != null) myCurrentSide = side;
-    }
+    myFocusTrackerSupport.processContextHints(myRequest, myContext);
  }

  @Override
  @CalledInAwt
  protected void updateContextHints() {
    super.updateContextHints();
-    if (myEditor1 != null && myEditor2 != null) {
-      myContext.putUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE, myCurrentSide);
-    }
+    myFocusTrackerSupport.updateContextHints(myRequest, myContext);
  }

  //
@@ -212,27 +182,13 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {


  private void destroyEditors() {
-    if (myEditor1 != null) {
+    if (getEditor1() != null) {
      assert myEditorProvider1 != null;
-      myEditorProvider1.disposeEditor(myEditor1);
+      myEditorProvider1.disposeEditor(getEditor1());
    }
-    if (myEditor2 != null) {
+    if (getEditor2() != null) {
      assert myEditorProvider2 != null;
-      myEditorProvider2.disposeEditor(myEditor2);
-    }
-  }
-
-  private void installEditorListeners() {
-    if (myEditor1 != null && myEditor2 != null) {
-      myEditor1.getComponent().addFocusListener(myEditorFocusListener1);
-      myEditor2.getComponent().addFocusListener(myEditorFocusListener2);
-    }
-  }
-
-  private void destroyEditorListeners() {
-    if (myEditor1 != null && myEditor2 != null) {
-      myEditor1.getComponent().removeFocusListener(myEditorFocusListener1);
-      myEditor2.getComponent().removeFocusListener(myEditorFocusListener2);
+      myEditorProvider2.disposeEditor(getEditor2());
    }
  }

@@ -364,8 +320,12 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  }

  @NotNull
-  Side getCurrentSide() {
-    return myCurrentSide;
+  public Side getCurrentSide() {
+    return myFocusTrackerSupport.getCurrentSide();
+  }
+
+  public void setCurrentSide(@NotNull Side side) {
+    myFocusTrackerSupport.setCurrentSide(side);
  }

  @Nullable
@@ -381,7 +341,7 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  @NotNull
  FileEditor getCurrentEditor() {
    //noinspection ConstantConditions
-    return getCurrentSide().select(myEditor1, myEditor2);
+    return getCurrentSide().select(getEditor1(), getEditor2());
  }

  @NotNull
@@ -446,14 +406,14 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  private class MyFocusOppositePaneAction extends FocusOppositePaneAction {
    @Override
    public void actionPerformed(@NotNull AnActionEvent e) {
-      assert myEditor1 != null && myEditor2 != null;
-      myCurrentSide = myCurrentSide.other();
+      assert getEditor1() != null && getEditor2() != null;
+      setCurrentSide(getCurrentSide().other());
      myPanel.requestFocus();
    }

    @Override
    public void update(@NotNull AnActionEvent e) {
-      e.getPresentation().setEnabled(myEditor1 != null && myEditor2 != null);
+      e.getPresentation().setEnabled(getEditor1() != null && getEditor2() != null);
    }
  }

@@ -465,7 +425,7 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
  @Override
  public Object getData(@NonNls String dataId) {
    if (CommonDataKeys.VIRTUAL_FILE.is(dataId)) {
-      return DiffUtil.getVirtualFile(myRequest, myCurrentSide);
+      return DiffUtil.getVirtualFile(myRequest, getCurrentSide());
    }
    return super.getData(dataId);
  }
@@ -476,17 +436,4 @@ public class BinaryDiffViewer extends ListenerDiffViewerBase {
      return -1;
    }
  }
-
-  private class MyEditorFocusListener extends FocusAdapter {
-    @NotNull private final Side mySide;
-
-    private MyEditorFocusListener(@NotNull Side side) {
-      mySide = side;
-    }
-
-    public void focusGained(FocusEvent e) {
-      if (myEditor1 == null || myEditor2 == null) return;
-      myCurrentSide = mySide;
-    }
-  }
 }
@@ -86,7 +86,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    mySyncScrollable = new MySyncScrollable();
    myPrevNextDifferenceIterable = new MyPrevNextDifferenceIterable();
    myStatusPanel = new MyStatusPanel();
-    myFoldingModel = createFoldingModel(myEditor1, myEditor2);
+    myFoldingModel = createFoldingModel(getEditor1(), getEditor2());

    myModifierProvider = new ModifierProvider();
  }
@@ -192,10 +192,10 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    try {
      indicator.checkCanceled();

-      assert myActualContent1 != null || myActualContent2 != null;
+      assert getActualContent1() != null || getActualContent2() != null;

-      if (myActualContent1 == null) {
-        final DocumentContent content = myActualContent2;
+      if (getActualContent1() == null) {
+        final DocumentContent content = getActualContent2();
        final Document document = content.getDocument();

        CompareData data = ApplicationManager.getApplication().runReadAction(new Computable<CompareData>() {
@@ -210,8 +210,8 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
        return apply(data);
      }

-      if (myActualContent2 == null) {
-        final DocumentContent content = myActualContent1;
+      if (getActualContent2() == null) {
+        final DocumentContent content = getActualContent1();
        final Document document = content.getDocument();

        CompareData data = ApplicationManager.getApplication().runReadAction(new Computable<CompareData>() {
@@ -226,8 +226,8 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
        return apply(data);
      }

-      final DocumentContent content1 = myActualContent1;
-      final DocumentContent content2 = myActualContent2;
+      final DocumentContent content1 = getActualContent1();
+      final DocumentContent content2 = getActualContent2();
      final Document document1 = content1.getDocument();
      final Document document2 = content2.getDocument();

@@ -284,8 +284,8 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    return new Runnable() {
      @Override
      public void run() {
-        if (myEditor1 != null && myEditor1.getDocument().getModificationStamp() != data.getStamp1()) return;
-        if (myEditor2 != null && myEditor2.getDocument().getModificationStamp() != data.getStamp2()) return;
+        if (getEditor1() != null && getEditor1().getDocument().getModificationStamp() != data.getStamp1()) return;
+        if (getEditor2() != null && getEditor2().getDocument().getModificationStamp() != data.getStamp2()) return;

        if (myFoldingModel != null) myFoldingModel.updateContext(myRequest, getFoldingModelSettings());
        clearDiffPresentation();
@@ -294,7 +294,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {

        if (data.getFragments() != null) {
          for (LineFragment fragment : data.getFragments()) {
-            myDiffChanges.add(new SimpleDiffChange(SimpleDiffViewer.this, fragment, myEditor1, myEditor2,
+            myDiffChanges.add(new SimpleDiffChange(SimpleDiffViewer.this, fragment, getEditor1(), getEditor2(),
                                                   getHighlightPolicy().isFineFragments()));
          }
        }
@@ -353,13 +353,13 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
  protected void onBeforeDocumentChange(@NotNull DocumentEvent e) {
    super.onBeforeDocumentChange(e);
    if (myDiffChanges.isEmpty()) return;
-    if (myEditor1 == null || myEditor2 == null) return;
+    if (getEditor1() == null || getEditor2() == null) return;

    Side side;
-    if (e.getDocument() == myEditor1.getDocument()) {
+    if (e.getDocument() == getEditor1().getDocument()) {
      side = Side.LEFT;
    }
-    else if (e.getDocument() == myEditor2.getDocument()) {
+    else if (e.getDocument() == getEditor2().getDocument()) {
      side = Side.RIGHT;
    }
    else {
@@ -401,7 +401,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
  @CalledInAwt
  protected boolean doScrollToChange(@NotNull ScrollToPolicy scrollToPolicy) {
    if (myDiffChanges.isEmpty()) return false;
-    if (myEditor1 == null || myEditor2 == null) return true;
+    if (getEditor1() == null || getEditor2() == null) return true;

    SimpleDiffChange targetChange;
    switch (scrollToPolicy) {
@@ -421,7 +421,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
  }

  private void doScrollToChange(@NotNull SimpleDiffChange change, final boolean animated) {
-    if (myEditor1 == null || myEditor2 == null) return;
+    if (getEditor1() == null || getEditor2() == null) return;
    assert mySyncScrollSupport != null;

    final int line1 = change.getStartLine(Side.LEFT);
@@ -429,14 +429,14 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    final int endLine1 = change.getEndLine(Side.LEFT);
    final int endLine2 = change.getEndLine(Side.RIGHT);

-    DiffUtil.moveCaret(myEditor1, line1);
-    DiffUtil.moveCaret(myEditor2, line2);
+    DiffUtil.moveCaret(getEditor1(), line1);
+    DiffUtil.moveCaret(getEditor2(), line2);

    mySyncScrollSupport.makeVisible(getCurrentSide(), line1, endLine1, line2, endLine2, animated);
  }

  protected boolean doScrollToContext(@NotNull DiffNavigationContext context) {
-    if (myEditor2 == null) return false;
+    if (getEditor2() == null) return false;

    ChangedLinesIterator changedLinesIterator = new ChangedLinesIterator(Side.RIGHT);
    NavigationContextChecker checker = new NavigationContextChecker(changedLinesIterator, context);
@@ -492,7 +492,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
  @NotNull
  @CalledInAwt
  private List<SimpleDiffChange> getSelectedChanges(@NotNull Side side) {
-    EditorEx editor = side.select(myEditor1, myEditor2);
+    EditorEx editor = side.select(getEditor1(), getEditor2());
    if (editor == null) return Collections.emptyList();

    final BitSet lines = DiffUtil.getSelectedLines(editor);
@@ -512,7 +512,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
  @Nullable
  @CalledInAwt
  private SimpleDiffChange getSelectedChange(@NotNull Side side) {
-    EditorEx editor = side.select(myEditor1, myEditor2);
+    EditorEx editor = side.select(getEditor1(), getEditor2());
    if (editor == null) return null;

    int caretLine = editor.getCaretModel().getLogicalPosition().line;
@@ -629,19 +629,19 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    @Override
    public void update(@NotNull AnActionEvent e) {
      Editor editor = e.getData(CommonDataKeys.EDITOR);
-      Side side = Side.fromLeft(editor == myEditor1);
+      Side side = Side.fromLeft(editor == getEditor1());

-      if (myEditor1 == null || myEditor2 == null) {
+      if (getEditor1() == null || getEditor2() == null) {
        e.getPresentation().setEnabledAndVisible(false);
        return;
      }

-      if (editor != myEditor1 && editor != myEditor2) {
+      if (editor != getEditor1() && editor != getEditor2()) {
        e.getPresentation().setEnabledAndVisible(false);
        return;
      }

-      Editor modifiedEditor = side.other(myModifyOpposite).select(myEditor1, myEditor2);
+      Editor modifiedEditor = side.other(myModifyOpposite).select(getEditor1(), getEditor2());
      if (!DiffUtil.isEditable(modifiedEditor)) {
        e.getPresentation().setEnabledAndVisible(false);
        return;
@@ -653,13 +653,13 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {

    @Override
    public void actionPerformed(@NotNull final AnActionEvent e) {
-      assert myEditor1 != null && myEditor2 != null;
+      assert getEditor1() != null && getEditor2() != null;

      Editor editor = e.getRequiredData(CommonDataKeys.EDITOR);
-      final Side side = Side.fromLeft(editor == myEditor1);
+      final Side side = Side.fromLeft(editor == getEditor1());
      final List<SimpleDiffChange> selectedChanges = getSelectedChanges(side);

-      Editor modifiedEditor = side.other(myModifyOpposite).select(myEditor1, myEditor2);
+      Editor modifiedEditor = side.other(myModifyOpposite).select(getEditor1(), getEditor2());
      String title = e.getPresentation().getText() + " selected changes";
      DiffUtil.executeWriteCommand(modifiedEditor.getDocument(), e.getProject(), title, new Runnable() {
        @Override
@@ -672,7 +672,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    protected boolean isSomeChangeSelected(@NotNull Side side) {
      if (myDiffChanges.isEmpty()) return false;

-      Editor editor = side.select(myEditor1, myEditor2);
+      Editor editor = side.select(getEditor1(), getEditor2());
      if (editor == null) return false;

      List<Caret> carets = editor.getCaretModel().getAllCarets();
@@ -753,12 +753,12 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {

  @CalledWithWriteLock
  public void replaceChange(@NotNull SimpleDiffChange change, @NotNull final Side sourceSide) {
-    assert myEditor1 != null && myEditor2 != null;
+    assert getEditor1() != null && getEditor2() != null;

    if (!change.isValid()) return;

-    final Document document1 = myEditor1.getDocument();
-    final Document document2 = myEditor2.getDocument();
+    final Document document1 = getEditor1().getDocument();
+    final Document document2 = getEditor2().getDocument();

    DiffUtil.applyModification(sourceSide.other().select(document1, document2),
                               change.getStartLine(sourceSide.other()), change.getEndLine(sourceSide.other()),
@@ -771,13 +771,13 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {

  @CalledWithWriteLock
  public void appendChange(@NotNull SimpleDiffChange change, @NotNull final Side sourceSide) {
-    assert myEditor1 != null && myEditor2 != null;
+    assert getEditor1() != null && getEditor2() != null;

    if (!change.isValid()) return;
    if (change.getStartLine(sourceSide) == change.getEndLine(sourceSide)) return;

-    final Document document1 = myEditor1.getDocument();
-    final Document document2 = myEditor2.getDocument();
+    final Document document1 = getEditor1().getDocument();
+    final Document document2 = getEditor2().getDocument();

    DiffUtil.applyModification(sourceSide.other().select(document1, document2),
                               change.getEndLine(sourceSide.other()), change.getEndLine(sourceSide.other()),
@@ -807,7 +807,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
    private AllLinesIterator(@NotNull Side side) {
      mySide = side;

-      Editor editor = mySide.select(myEditor1, myEditor2);
+      Editor editor = mySide.select(getEditor1(), getEditor2());
      assert editor != null;
      myDocument = editor.getDocument();
    }
@@ -858,7 +858,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
      int line1 = change.getStartLine(mySide);
      int line2 = change.getEndLine(mySide);

-      Editor editor = mySide.select(myEditor1, myEditor2);
+      Editor editor = mySide.select(getEditor1(), getEditor2());
      assert editor != null;
      Document document = editor.getDocument();

@@ -907,28 +907,28 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {

    @Override
    protected void processHelper(@NotNull ScrollHelper helper) {
-      assert myEditor1 != null && myEditor2 != null;
+      assert getEditor1() != null && getEditor2() != null;

      if (!helper.process(0, 0)) return;
      for (SimpleDiffChange diffChange : myDiffChanges) {
        if (!helper.process(diffChange.getStartLine(Side.LEFT), diffChange.getStartLine(Side.RIGHT))) return;
        if (!helper.process(diffChange.getEndLine(Side.LEFT), diffChange.getEndLine(Side.RIGHT))) return;
      }
-      helper.process(myEditor1.getDocument().getLineCount(), myEditor2.getDocument().getLineCount());
+      helper.process(getEditor1().getDocument().getLineCount(), getEditor2().getDocument().getLineCount());
    }
  }

  private class MyDividerPainter implements DiffSplitter.Painter, DiffDividerDrawUtil.DividerPaintable {
    @Override
    public void paint(@NotNull Graphics g, @NotNull JComponent divider) {
-      if (myEditor1 == null || myEditor2 == null) return;
-      Graphics2D gg = DiffDividerDrawUtil.getDividerGraphics(g, divider, myEditor1.getComponent());
+      if (getEditor1() == null || getEditor2() == null) return;
+      Graphics2D gg = DiffDividerDrawUtil.getDividerGraphics(g, divider, getEditor1().getComponent());

-      gg.setColor(DiffDrawUtil.getDividerColor(myEditor1));
+      gg.setColor(DiffDrawUtil.getDividerColor(getEditor1()));
      gg.fill(gg.getClipBounds());

-      //DividerPolygonUtil.paintSimplePolygons(gg, divider.getWidth(), myEditor1, myEditor2, this);
-      DiffDividerDrawUtil.paintPolygons(gg, divider.getWidth(), myEditor1, myEditor2, this);
+      //DividerPolygonUtil.paintSimplePolygons(gg, divider.getWidth(), getEditor1(), getEditor2(), this);
+      DiffDividerDrawUtil.paintPolygons(gg, divider.getWidth(), getEditor1(), getEditor2(), this);

      if (myFoldingModel != null) myFoldingModel.paintOnDivider(gg, divider);

@@ -940,7 +940,7 @@ public class SimpleDiffViewer extends TwosideTextDiffViewer {
      for (SimpleDiffChange diffChange : myDiffChanges) {
        if (!handler.process(diffChange.getStartLine(Side.LEFT), diffChange.getEndLine(Side.LEFT),
                             diffChange.getStartLine(Side.RIGHT), diffChange.getEndLine(Side.RIGHT),
-                             diffChange.getDiffType().getColor(myEditor1))) {
+                             diffChange.getDiffType().getColor(getEditor1()))) {
          return;
        }
      }
@@ -34,7 +34,7 @@ import java.util.List;

 public class SimpleThreesideDiffChange {
  @NotNull private final MergeLineFragment myFragment;
-  @NotNull private final List<EditorEx> myEditors;
+  @NotNull private final List<? extends EditorEx> myEditors;

  @NotNull private ConflictType myType;

@@ -44,7 +44,7 @@ public class SimpleThreesideDiffChange {
  private int[] myLineEndShifts = new int[3];

  public SimpleThreesideDiffChange(@NotNull MergeLineFragment fragment,
-                                   @NotNull List<EditorEx> editors,
+                                   @NotNull List<? extends EditorEx> editors,
                                   @NotNull ComparisonPolicy policy) {
    myFragment = fragment;
    myEditors = editors;
@@ -154,7 +154,7 @@ public class SimpleThreesideDiffChange {

  @NotNull
  private static ConflictType calcType(@NotNull MergeLineFragment fragment,
-                                       @NotNull List<EditorEx> editors,
+                                       @NotNull List<? extends EditorEx> editors,
                                       @NotNull ComparisonPolicy policy) {
    boolean isLeftEmpty = isIntervalEmpty(fragment, ThreeSide.LEFT);
    boolean isBaseEmpty = isIntervalEmpty(fragment, ThreeSide.BASE);
@@ -192,7 +192,7 @@ public class SimpleThreesideDiffChange {
  }

  private static boolean compareLeftAndRight(@NotNull MergeLineFragment fragment,
-                                             @NotNull List<EditorEx> editors,
+                                             @NotNull List<? extends EditorEx> editors,
                                             @NotNull ComparisonPolicy policy) {
    CharSequence content1 = getRangeContent(fragment, editors, ThreeSide.LEFT);
    CharSequence content2 = getRangeContent(fragment, editors, ThreeSide.RIGHT);
@@ -209,7 +209,7 @@ public class SimpleThreesideDiffChange {
  }

  private static boolean compareWithBase(@NotNull MergeLineFragment fragment,
-                                         @NotNull List<EditorEx> editors,
+                                         @NotNull List<? extends EditorEx> editors,
                                         @NotNull ThreeSide side) {
    CharSequence content1 = getRangeContent(fragment, editors, ThreeSide.BASE);
    CharSequence content2 = getRangeContent(fragment, editors, side);
@@ -219,7 +219,7 @@ public class SimpleThreesideDiffChange {

  @Nullable
  private static CharSequence getRangeContent(@NotNull MergeLineFragment fragment,
-                                              @NotNull List<EditorEx> editors,
+                                              @NotNull List<? extends EditorEx> editors,
                                              @NotNull ThreeSide side) {
    DocumentEx document = side.select(editors).getDocument();
    int line1 = fragment.getStartLine(side);
@@ -82,7 +82,7 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
    mySyncScrollable2 = new MySyncScrollable(Side.RIGHT);
    myPrevNextDifferenceIterable = new MyPrevNextDifferenceIterable();
    myStatusPanel = new MyStatusPanel();
-    myFoldingModel = new MyFoldingModel(myEditors.toArray(new EditorEx[3]), this);
+    myFoldingModel = new MyFoldingModel(getEditors().toArray(new EditorEx[3]), this);
  }

  @Override
@@ -233,7 +233,7 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
        clearDiffPresentation();

        for (MergeLineFragment fragment : fragments) {
-          myDiffChanges.add(new SimpleThreesideDiffChange(fragment, myEditors, comparisonPolicy));
+          myDiffChanges.add(new SimpleThreesideDiffChange(fragment, getEditors(), comparisonPolicy));
        }

        myFoldingModel.install(fragments, myRequest, getFoldingModelSettings());
@@ -280,13 +280,13 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
    if (myDiffChanges.isEmpty()) return;

    ThreeSide side;
-    if (e.getDocument() == myEditors.get(0).getDocument()) {
+    if (e.getDocument() == getEditor(0).getDocument()) {
      side = ThreeSide.LEFT;
    }
-    else if (e.getDocument() == myEditors.get(1).getDocument()) {
+    else if (e.getDocument() == getEditor(1).getDocument()) {
      side = ThreeSide.BASE;
    }
-    else if (e.getDocument() == myEditors.get(2).getDocument()) {
+    else if (e.getDocument() == getEditor(2).getDocument()) {
      side = ThreeSide.RIGHT;
    }
    else {
@@ -396,7 +396,7 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
  @Nullable
  @CalledInAwt
  private SimpleThreesideDiffChange getSelectedChange(@NotNull ThreeSide side) {
-    EditorEx editor = side.select(myEditors);
+    EditorEx editor = side.select(getEditors());

    int caretLine = editor.getCaretModel().getLogicalPosition().line;

@@ -554,7 +554,7 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
        if (!helper.process(diffChange.getStartLine(left), diffChange.getStartLine(right))) return;
        if (!helper.process(diffChange.getEndLine(left), diffChange.getEndLine(right))) return;
      }
-      helper.process(left.select(myEditors).getDocument().getLineCount(), right.select(myEditors).getDocument().getLineCount());
+      helper.process(left.select(getEditors()).getDocument().getLineCount(), right.select(getEditors()).getDocument().getLineCount());
    }
  }

@@ -574,7 +574,7 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {
        if (!diffChange.getType().isChange(mySide)) continue;
        if (!handler.process(diffChange.getStartLine(left), diffChange.getEndLine(left),
                             diffChange.getStartLine(right), diffChange.getEndLine(right),
-                             diffChange.getDiffType().getColor(myEditors.get(0)))) {
+                             diffChange.getDiffType().getColor(getEditor(0)))) {
          return;
        }
      }
@@ -592,13 +592,13 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {

    @Override
    public void paint(@NotNull Graphics g, @NotNull JComponent divider) {
-      Graphics2D gg = DiffDividerDrawUtil.getDividerGraphics(g, divider, myEditors.get(0).getComponent());
+      Graphics2D gg = DiffDividerDrawUtil.getDividerGraphics(g, divider, getEditor(0).getComponent());

-      gg.setColor(DiffDrawUtil.getDividerColor(myEditors.get(0)));
+      gg.setColor(DiffDrawUtil.getDividerColor(getEditor(0)));
      gg.fill(gg.getClipBounds());

-      Editor editor1 = mySide.select(myEditors.get(0), myEditors.get(1));
-      Editor editor2 = mySide.select(myEditors.get(1), myEditors.get(2));
+      Editor editor1 = mySide.select(getEditor(0), getEditor(1));
+      Editor editor2 = mySide.select(getEditor(1), getEditor(2));

      //DividerPolygonUtil.paintSimplePolygons(gg, divider.getWidth(), editor1, editor2, myPaintable);
      DiffDividerDrawUtil.paintPolygons(gg, divider.getWidth(), editor1, editor2, myPaintable);
@@ -614,8 +614,8 @@ public class SimpleThreesideDiffViewer extends ThreesideTextDiffViewer {

    @Override
    public void call(Graphics g) {
-      EditorEx editor1 = myEditors.get(1);
-      EditorEx editor2 = myEditors.get(2);
+      EditorEx editor1 = getEditor(1);
+      EditorEx editor2 = getEditor(2);

      int width = editor1.getScrollPane().getVerticalScrollBar().getWidth();
      DiffDividerDrawUtil.paintPolygonsOnScrollbar((Graphics2D)g, width, editor1, editor2, myPaintable);
@@ -0,0 +1,188 @@
+/*
+ * Copyright 2000-2015 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.diff.tools.util;
+
+import com.intellij.diff.DiffContext;
+import com.intellij.diff.requests.DiffRequest;
+import com.intellij.diff.util.DiffUserDataKeys;
+import com.intellij.diff.util.Side;
+import com.intellij.diff.util.ThreeSide;
+import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.fileEditor.FileEditor;
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import javax.swing.*;
+import java.awt.event.FocusAdapter;
+import java.awt.event.FocusEvent;
+import java.util.List;
+
+public class FocusTrackerSupport<T> {
+  public static class TwosideFocusTrackerSupport {
+    @NotNull private Side myCurrentSide;
+
+    private final boolean myDumbMode;
+    @Nullable private final MyFocusListener myListener1;
+    @Nullable private final MyFocusListener myListener2;
+
+    public TwosideFocusTrackerSupport(@Nullable Editor editor1, @Nullable Editor editor2) {
+      this(getComponent(editor1), getComponent(editor2));
+    }
+
+    public TwosideFocusTrackerSupport(@Nullable FileEditor editor1, @Nullable FileEditor editor2) {
+      this(getComponent(editor1), getComponent(editor2));
+    }
+
+    public TwosideFocusTrackerSupport(@Nullable JComponent component1, @Nullable JComponent component2) {
+      assert component1 != null || component2 != null;
+      myCurrentSide = component2 != null ? Side.RIGHT : Side.LEFT;
+
+      myDumbMode = component1 == null || component2 == null;
+      if (!myDumbMode) {
+        myListener1 = new MyFocusListener(Side.LEFT);
+        component1.addFocusListener(myListener1);
+
+        myListener2 = new MyFocusListener(Side.RIGHT);
+        component2.addFocusListener(myListener2);
+      }
+      else {
+        myListener1 = null;
+        myListener2 = null;
+      }
+    }
+
+    @NotNull
+    public Side getCurrentSide() {
+      return myCurrentSide;
+    }
+
+    public void setCurrentSide(@NotNull Side side) {
+      if (myDumbMode) return;
+      myCurrentSide = side;
+    }
+
+    public void processContextHints(@NotNull DiffRequest request, @NotNull DiffContext context) {
+      Side side = context.getUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE);
+      if (side != null) setCurrentSide(side);
+    }
+
+    public void updateContextHints(@NotNull DiffRequest request, @NotNull DiffContext context) {
+      if (myDumbMode) return;
+      context.putUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE, myCurrentSide);
+    }
+
+    private class MyFocusListener extends FocusAdapter {
+      @NotNull private final Side mySide;
+
+      private MyFocusListener(@NotNull Side side) {
+        mySide = side;
+      }
+
+      public void focusGained(FocusEvent e) {
+        myCurrentSide = mySide;
+      }
+    }
+  }
+
+  public static class ThreesideFocusTrackerSupport {
+    @NotNull private ThreeSide myCurrentSide;
+
+    private final boolean myDumbMode;
+    @Nullable private final MyFocusListener myListener1;
+    @Nullable private final MyFocusListener myListener2;
+    @Nullable private final MyFocusListener myListener3;
+
+    public ThreesideFocusTrackerSupport(@NotNull List<? extends Editor> editors) {
+      this(editors.get(0), editors.get(1), editors.get(2));
+    }
+
+    public ThreesideFocusTrackerSupport(@Nullable Editor editor1, @Nullable Editor editor2, @Nullable Editor editor3) {
+      this(getComponent(editor1), getComponent(editor2), getComponent(editor3));
+    }
+
+    public ThreesideFocusTrackerSupport(@Nullable FileEditor editor1, @Nullable FileEditor editor2, @Nullable FileEditor editor3) {
+      this(getComponent(editor1), getComponent(editor2), getComponent(editor3));
+    }
+
+    public ThreesideFocusTrackerSupport(@Nullable JComponent component1, @Nullable JComponent component2, @Nullable JComponent component3) {
+      assert component1 != null || component2 != null || component3 != null;
+      myCurrentSide = component2 != null ? ThreeSide.BASE : component1 != null ? ThreeSide.LEFT : ThreeSide.RIGHT;
+
+      boolean c1 = component1 != null;
+      boolean c2 = component2 != null;
+      boolean c3 = component3 != null;
+      myDumbMode = (!c1 && !c2) || (!c1 && !c3) || (!c2 && !c3); // only one not-null element
+
+      if (!myDumbMode) {
+        myListener1 = component1 != null ? new MyFocusListener(ThreeSide.LEFT) : null;
+        if (component1 != null) component1.addFocusListener(myListener1);
+
+        myListener2 = component2 != null ? new MyFocusListener(ThreeSide.BASE) : null;
+        if (component2 != null) component2.addFocusListener(myListener2);
+
+        myListener3 = component3 != null ? new MyFocusListener(ThreeSide.RIGHT) : null;
+        if (component3 != null) component3.addFocusListener(myListener3);
+      }
+      else {
+        myListener1 = null;
+        myListener2 = null;
+        myListener3 = null;
+      }
+    }
+
+    @NotNull
+    public ThreeSide getCurrentSide() {
+      return myCurrentSide;
+    }
+
+    public void setCurrentSide(@NotNull ThreeSide side) {
+      if (myDumbMode || side.select(myListener1, myListener2, myListener3) == null) return;
+      myCurrentSide = side;
+    }
+
+    public void processContextHints(@NotNull DiffRequest request, @NotNull DiffContext context) {
+      ThreeSide side = context.getUserData(DiffUserDataKeys.PREFERRED_FOCUS_THREESIDE);
+      if (side != null) setCurrentSide(side);
+    }
+
+    public void updateContextHints(@NotNull DiffRequest request, @NotNull DiffContext context) {
+      if (myDumbMode) return;
+      context.putUserData(DiffUserDataKeys.PREFERRED_FOCUS_THREESIDE, myCurrentSide);
+    }
+
+    private class MyFocusListener extends FocusAdapter {
+      @NotNull private final ThreeSide mySide;
+
+      private MyFocusListener(@NotNull ThreeSide side) {
+        mySide = side;
+      }
+
+      public void focusGained(FocusEvent e) {
+        myCurrentSide = mySide;
+      }
+    }
+  }
+
+  @Nullable
+  private static JComponent getComponent(@Nullable Editor editor) {
+    return editor != null ? editor.getContentComponent() : null;
+  }
+
+  @Nullable
+  private static JComponent getComponent(@Nullable FileEditor editor) {
+    return editor != null ? editor.getComponent() : null;
+  }
+}
@@ -24,12 +24,12 @@ import com.intellij.diff.requests.ContentDiffRequest;
 import com.intellij.diff.requests.DiffRequest;
 import com.intellij.diff.requests.SimpleDiffRequest;
 import com.intellij.diff.tools.util.DiffDataKeys;
+import com.intellij.diff.tools.util.FocusTrackerSupport.ThreesideFocusTrackerSupport;
 import com.intellij.diff.tools.util.SimpleDiffPanel;
 import com.intellij.diff.tools.util.SyncScrollSupport;
 import com.intellij.diff.tools.util.SyncScrollSupport.ThreesideSyncScrollSupport;
 import com.intellij.diff.tools.util.base.InitialScrollPositionSupport;
 import com.intellij.diff.tools.util.base.TextDiffViewerBase;
-import com.intellij.diff.util.DiffUserDataKeys;
 import com.intellij.diff.util.DiffUtil;
 import com.intellij.diff.util.Side;
 import com.intellij.diff.util.ThreeSide;
@@ -55,8 +55,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;

 import javax.swing.*;
-import java.awt.event.FocusAdapter;
-import java.awt.event.FocusEvent;
 import java.util.ArrayList;
 import java.util.List;

@@ -68,22 +66,17 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
  @NotNull protected final SimpleDiffPanel myPanel;
  @NotNull protected final ThreesideTextContentPanel myContentPanel;

-  @NotNull protected final List<EditorEx> myEditors;
+  @NotNull private final List<EditorEx> myEditors;
+  @NotNull private final List<DocumentContent> myActualContents;

-  @NotNull protected final List<DocumentContent> myActualContents;
-
-  @NotNull private final List<MyEditorFocusListener> myEditorFocusListeners =
-    ContainerUtil.newArrayList(new MyEditorFocusListener(ThreeSide.LEFT),
-                               new MyEditorFocusListener(ThreeSide.BASE),
-                               new MyEditorFocusListener(ThreeSide.RIGHT));
  @NotNull private final MyVisibleAreaListener myVisibleAreaListener1 = new MyVisibleAreaListener(Side.LEFT);
  @NotNull private final MyVisibleAreaListener myVisibleAreaListener2 = new MyVisibleAreaListener(Side.RIGHT);

  @NotNull protected final MySetEditorSettingsAction myEditorSettingsAction;

-  @Nullable private ThreesideSyncScrollSupport mySyncScrollListener;
+  @NotNull private final ThreesideFocusTrackerSupport myFocusTrackerSupport;

-  @NotNull private ThreeSide myCurrentSide;
+  @Nullable private ThreesideSyncScrollSupport mySyncScrollSupport;

  public ThreesideTextDiffViewer(@NotNull DiffContext context, @NotNull ContentDiffRequest request) {
    super(context, request);
@@ -95,11 +88,10 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {


    myEditors = createEditors();
-    List<JComponent> titlePanel = DiffUtil.createTextTitles(myRequest, myEditors);
+    List<JComponent> titlePanel = DiffUtil.createTextTitles(myRequest, getEditors());

-    myCurrentSide = ThreeSide.BASE;
-
-    myContentPanel = new ThreesideTextContentPanel(myEditors, titlePanel);
+    myFocusTrackerSupport = new ThreesideFocusTrackerSupport(getEditors());
+    myContentPanel = new ThreesideTextContentPanel(getEditors(), titlePanel);

    myPanel = new SimpleDiffPanel(myContentPanel, this, context);

@@ -121,15 +113,14 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
  @CalledInAwt
  protected void processContextHints() {
    super.processContextHints();
-    ThreeSide side = myContext.getUserData(DiffUserDataKeys.PREFERRED_FOCUS_THREESIDE);
-    if (side != null) myCurrentSide = side;
+    myFocusTrackerSupport.processContextHints(myRequest, myContext);
  }

  @Override
  @CalledInAwt
  protected void updateContextHints() {
    super.updateContextHints();
-    myContext.putUserData(DiffUserDataKeys.PREFERRED_FOCUS_THREESIDE, myCurrentSide);
+    myFocusTrackerSupport.updateContextHints(myRequest, myContext);
  }

  @NotNull
@@ -137,8 +128,8 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
    boolean[] forceReadOnly = checkForceReadOnly();
    List<EditorEx> editors = new ArrayList<EditorEx>(3);

-    for (int i = 0; i < myActualContents.size(); i++) {
-      DocumentContent content = myActualContents.get(i);
+    for (int i = 0; i < getActualContents().size(); i++) {
+      DocumentContent content = getActualContents().get(i);
      EditorEx editor = DiffUtil.createEditor(content.getDocument(), myProject, forceReadOnly[i], true);
      DiffUtil.configureEditor(editor, content, myProject);
      editors.add(editor);
@@ -155,7 +146,7 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
  }

  private void destroyEditors() {
-    for (EditorEx editor : myEditors) {
+    for (EditorEx editor : getEditors()) {
      myEditorFactory.releaseEditor(editor);
    }
  }
@@ -168,20 +159,17 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
  @Override
  protected void installEditorListeners() {
    super.installEditorListeners();
-    for (int i = 0; i < 3; i++) {
-      myEditors.get(i).getContentComponent().addFocusListener(myEditorFocusListeners.get(i));
-    }

-    myEditors.get(0).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener1);
-    myEditors.get(1).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener1);
+    getEditor(0).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener1);
+    getEditor(1).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener1);

-    myEditors.get(1).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener2);
-    myEditors.get(2).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener2);
+    getEditor(1).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener2);
+    getEditor(2).getScrollingModel().addVisibleAreaListener(myVisibleAreaListener2);

    SyncScrollSupport.SyncScrollable scrollable1 = getSyncScrollable(Side.LEFT);
    SyncScrollSupport.SyncScrollable scrollable2 = getSyncScrollable(Side.RIGHT);
    if (scrollable1 != null && scrollable2 != null) {
-      mySyncScrollListener = new ThreesideSyncScrollSupport(myEditors, scrollable1, scrollable2);
+      mySyncScrollSupport = new ThreesideSyncScrollSupport(getEditors(), scrollable1, scrollable2);
    }
  }

@@ -190,22 +178,18 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
  public void destroyEditorListeners() {
    super.destroyEditorListeners();

-    for (int i = 0; i < 3; i++) {
-      myEditors.get(i).getContentComponent().removeFocusListener(myEditorFocusListeners.get(i));
-    }
+    getEditor(0).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener1);
+    getEditor(1).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener1);

-    myEditors.get(0).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener1);
-    myEditors.get(1).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener1);
+    getEditor(1).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener2);
+    getEditor(2).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener2);

-    myEditors.get(1).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener2);
-    myEditors.get(2).getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener2);
-
-    mySyncScrollListener = null;
+    mySyncScrollSupport = null;
  }

  protected void disableSyncScrollSupport(boolean disable) {
-    if (mySyncScrollListener != null) {
-      mySyncScrollListener.setDisabled(disable);
+    if (mySyncScrollSupport != null) {
+      mySyncScrollSupport.setDisabled(disable);
    }
  }

@@ -238,12 +222,12 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {

  @NotNull
  public EditorEx getCurrentEditor() {
-    return myCurrentSide.select(myEditors);
+    return getCurrentSide().select(getEditors());
  }

  @NotNull
  public DocumentContent getCurrentContent() {
-    return myCurrentSide.select(myActualContents);
+    return getCurrentSide().select(getActualContents());
  }

  @NotNull
@@ -252,9 +236,23 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
    return myEditors;
  }

+  @NotNull
+  protected EditorEx getEditor(int index) {
+    return myEditors.get(index);
+  }
+
+  @NotNull
+  public List<DocumentContent> getActualContents() {
+    return myActualContents;
+  }
+
  @NotNull
  public ThreeSide getCurrentSide() {
-    return myCurrentSide;
+    return myFocusTrackerSupport.getCurrentSide();
+  }
+
+  public void setCurrentSide(@NotNull ThreeSide side) {
+    myFocusTrackerSupport.setCurrentSide(side);
  }

  //
@@ -263,9 +261,9 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {

  @CalledInAwt
  protected void scrollToLine(@NotNull ThreeSide side, int line) {
-    Editor editor = side.select(myEditors);
+    Editor editor = side.select(getEditors());
    DiffUtil.scrollEditor(editor, line, false);
-    myCurrentSide = side;
+    setCurrentSide(side);
  }

  @Nullable
@@ -365,26 +363,14 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {
      return getCurrentEditor();
    }
    else if (CommonDataKeys.VIRTUAL_FILE.is(dataId)) {
-      return DiffUtil.getVirtualFile(myRequest, myCurrentSide);
+      return DiffUtil.getVirtualFile(myRequest, getCurrentSide());
    }
    else if (DiffDataKeys.CURRENT_CONTENT.is(dataId)) {
      return getCurrentContent();
    }
    return super.getData(dataId);
  }
-
-  private class MyEditorFocusListener extends FocusAdapter {
-    @NotNull private final ThreeSide mySide;
-
-    private MyEditorFocusListener(@NotNull ThreeSide side) {
-      mySide = side;
-    }
-
-    public void focusGained(FocusEvent e) {
-      myCurrentSide = mySide;
-    }
-  }
-
+  
  private class MyVisibleAreaListener implements VisibleAreaListener {
    @NotNull Side mySide;

@@ -394,7 +380,7 @@ public abstract class ThreesideTextDiffViewer extends TextDiffViewerBase {

    @Override
    public void visibleAreaChanged(VisibleAreaEvent e) {
-      if (mySyncScrollListener != null) mySyncScrollListener.visibleAreaChanged(e);
+      if (mySyncScrollSupport != null) mySyncScrollSupport.visibleAreaChanged(e);
      if (Registry.is("diff.divider.repainting.fix")) {
        myContentPanel.repaint();
      }
@@ -24,12 +24,12 @@ import com.intellij.diff.contents.EmptyContent;
 import com.intellij.diff.requests.ContentDiffRequest;
 import com.intellij.diff.requests.DiffRequest;
 import com.intellij.diff.tools.util.DiffDataKeys;
+import com.intellij.diff.tools.util.FocusTrackerSupport.TwosideFocusTrackerSupport;
 import com.intellij.diff.tools.util.SimpleDiffPanel;
 import com.intellij.diff.tools.util.SyncScrollSupport;
 import com.intellij.diff.tools.util.SyncScrollSupport.TwosideSyncScrollSupport;
 import com.intellij.diff.tools.util.base.InitialScrollPositionSupport;
 import com.intellij.diff.tools.util.base.TextDiffViewerBase;
-import com.intellij.diff.util.DiffUserDataKeys;
 import com.intellij.diff.util.DiffUtil;
 import com.intellij.diff.util.Side;
 import com.intellij.openapi.actionSystem.AnActionEvent;
@@ -52,8 +52,6 @@ import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;

 import javax.swing.*;
-import java.awt.event.FocusAdapter;
-import java.awt.event.FocusEvent;
 import java.util.Collections;
 import java.util.List;

@@ -65,21 +63,19 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  @NotNull protected final SimpleDiffPanel myPanel;
  @NotNull protected final TwosideTextContentPanel myContentPanel;

-  @Nullable protected final EditorEx myEditor1;
-  @Nullable protected final EditorEx myEditor2;
+  @Nullable private final EditorEx myEditor1;
+  @Nullable private final EditorEx myEditor2;

-  @Nullable protected final DocumentContent myActualContent1;
-  @Nullable protected final DocumentContent myActualContent2;
+  @Nullable private final DocumentContent myActualContent1;
+  @Nullable private final DocumentContent myActualContent2;

  @NotNull protected final MySetEditorSettingsAction myEditorSettingsAction;

-  @NotNull private final MyEditorFocusListener myEditorFocusListener1 = new MyEditorFocusListener(Side.LEFT);
-  @NotNull private final MyEditorFocusListener myEditorFocusListener2 = new MyEditorFocusListener(Side.RIGHT);
  @NotNull private final MyVisibleAreaListener myVisibleAreaListener = new MyVisibleAreaListener();

-  @Nullable protected TwosideSyncScrollSupport mySyncScrollSupport;
+  @NotNull private final TwosideFocusTrackerSupport myFocusTrackerSupport;

-  @NotNull private Side myCurrentSide;
+  @Nullable protected TwosideSyncScrollSupport mySyncScrollSupport;

  public TwosideTextDiffViewer(@NotNull DiffContext context, @NotNull ContentDiffRequest request) {
    super(context, request);
@@ -97,9 +93,8 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
    myEditor2 = editors.get(1);
    assert myEditor1 != null || myEditor2 != null;

-    myCurrentSide = myEditor1 == null ? Side.RIGHT : Side.LEFT;
-
-    myContentPanel = new TwosideTextContentPanel(titlePanel, myEditor1, myEditor2);
+    myFocusTrackerSupport = new TwosideFocusTrackerSupport(getEditor1(), getEditor2());
+    myContentPanel = new TwosideTextContentPanel(titlePanel, getEditor1(), getEditor2());

    myPanel = new SimpleDiffPanel(myContentPanel, this, context);

@@ -124,25 +119,14 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  @CalledInAwt
  protected void processContextHints() {
    super.processContextHints();
-    if (myEditor1 == null) {
-      myCurrentSide = Side.RIGHT;
-    }
-    else if (myEditor2 == null) {
-      myCurrentSide = Side.LEFT;
-    }
-    else {
-      Side side = myContext.getUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE);
-      if (side != null) myCurrentSide = side;
-    }
+    myFocusTrackerSupport.processContextHints(myRequest, myContext);
  }

  @Override
  @CalledInAwt
  protected void updateContextHints() {
    super.updateContextHints();
-    if (myEditor1 != null && myEditor2 != null) {
-      myContext.putUserData(DiffUserDataKeys.PREFERRED_FOCUS_SIDE, myCurrentSide);
-    }
+    myFocusTrackerSupport.updateContextHints(myRequest, myContext);
  }

  @NotNull
@@ -152,13 +136,13 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
    // TODO: we may want to set editor highlighter in init() to speedup editor initialization
    EditorEx editor1 = null;
    EditorEx editor2 = null;
-    if (myActualContent1 != null) {
-      editor1 = DiffUtil.createEditor(myActualContent1.getDocument(), myProject, forceReadOnly[0], true);
-      DiffUtil.configureEditor(editor1, myActualContent1, myProject);
+    if (getActualContent1() != null) {
+      editor1 = DiffUtil.createEditor(getActualContent1().getDocument(), myProject, forceReadOnly[0], true);
+      DiffUtil.configureEditor(editor1, getActualContent1(), myProject);
    }
-    if (myActualContent2 != null) {
-      editor2 = DiffUtil.createEditor(myActualContent2.getDocument(), myProject, forceReadOnly[1], true);
-      DiffUtil.configureEditor(editor2, myActualContent2, myProject);
+    if (getActualContent2() != null) {
+      editor2 = DiffUtil.createEditor(getActualContent2().getDocument(), myProject, forceReadOnly[1], true);
+      DiffUtil.configureEditor(editor2, getActualContent2(), myProject);
    }
    if (editor1 != null && editor2 != null) {
      editor1.setVerticalScrollbarOrientation(EditorEx.VERTICAL_SCROLLBAR_LEFT);
@@ -186,26 +170,24 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  //

  private void destroyEditors() {
-    if (myEditor1 != null) myEditorFactory.releaseEditor(myEditor1);
-    if (myEditor2 != null) myEditorFactory.releaseEditor(myEditor2);
+    if (getEditor1() != null) myEditorFactory.releaseEditor(getEditor1());
+    if (getEditor2() != null) myEditorFactory.releaseEditor(getEditor2());
  }

  @CalledInAwt
  @Override
  protected void installEditorListeners() {
    super.installEditorListeners();
-    if (myEditor1 != null) {
-      myEditor1.getContentComponent().addFocusListener(myEditorFocusListener1);
-      myEditor1.getScrollingModel().addVisibleAreaListener(myVisibleAreaListener);
+    if (getEditor1() != null) {
+      getEditor1().getScrollingModel().addVisibleAreaListener(myVisibleAreaListener);
    }
-    if (myEditor2 != null) {
-      myEditor2.getContentComponent().addFocusListener(myEditorFocusListener2);
-      myEditor2.getScrollingModel().addVisibleAreaListener(myVisibleAreaListener);
+    if (getEditor2() != null) {
+      getEditor2().getScrollingModel().addVisibleAreaListener(myVisibleAreaListener);
    }
-    if (myEditor1 != null && myEditor2 != null) {
+    if (getEditor1() != null && getEditor2() != null) {
      SyncScrollSupport.SyncScrollable scrollable = getSyncScrollable();
      if (scrollable != null) {
-        mySyncScrollSupport = new TwosideSyncScrollSupport(myEditor1, myEditor2, scrollable);
+        mySyncScrollSupport = new TwosideSyncScrollSupport(getEditor1(), getEditor2(), scrollable);
      }
    }
  }
@@ -214,13 +196,11 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  @Override
  protected void destroyEditorListeners() {
    super.destroyEditorListeners();
-    if (myEditor1 != null) {
-      myEditor1.getContentComponent().removeFocusListener(myEditorFocusListener1);
-      myEditor1.getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener);
+    if (getEditor1() != null) {
+      getEditor1().getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener);
    }
-    if (myEditor2 != null) {
-      myEditor2.getContentComponent().removeFocusListener(myEditorFocusListener2);
-      myEditor2.getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener);
+    if (getEditor2() != null) {
+      getEditor2().getScrollingModel().removeVisibleAreaListener(myVisibleAreaListener);
    }
    mySyncScrollSupport = null;
  }
@@ -238,14 +218,14 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  @NotNull
  @Override
  protected List<? extends EditorEx> getEditors() {
-    if (myEditor1 != null && myEditor2 != null) {
-      return ContainerUtil.list(myEditor1, myEditor2);
+    if (getEditor1() != null && getEditor2() != null) {
+      return ContainerUtil.list(getEditor1(), getEditor2());
    }
-    if (myEditor1 != null) {
-      return Collections.singletonList(myEditor1);
+    if (getEditor1() != null) {
+      return Collections.singletonList(getEditor1());
    }
-    if (myEditor2 != null) {
-      return Collections.singletonList(myEditor2);
+    if (getEditor2() != null) {
+      return Collections.singletonList(getEditor2());
    }
    return Collections.emptyList();
  }
@@ -264,19 +244,23 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {

  @NotNull
  public Side getCurrentSide() {
-    return myCurrentSide;
+    return myFocusTrackerSupport.getCurrentSide();
+  }
+
+  public void setCurrentSide(@NotNull Side side) {
+    myFocusTrackerSupport.setCurrentSide(side);
  }

  @NotNull
  public EditorEx getCurrentEditor() {
    //noinspection ConstantConditions
-    return getCurrentSide().select(myEditor1, myEditor2);
+    return getCurrentSide().select(getEditor1(), getEditor2());
  }

  @NotNull
  public DocumentContent getCurrentContent() {
    //noinspection ConstantConditions
-    return getCurrentSide().select(myActualContent1, myActualContent2);
+    return getCurrentSide().select(getActualContent1(), getActualContent2());
  }

  @Nullable
@@ -289,6 +273,16 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
    return myEditor2;
  }

+  @Nullable
+  public DocumentContent getActualContent1() {
+    return myActualContent1;
+  }
+
+  @Nullable
+  public DocumentContent getActualContent2() {
+    return myActualContent2;
+  }
+
  //
  // Abstract
  //
@@ -303,10 +297,10 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {

  @CalledInAwt
  protected void scrollToLine(@NotNull Side side, int line) {
-    Editor editor = side.select(myEditor1, myEditor2);
+    Editor editor = side.select(getEditor1(), getEditor2());
    if (editor == null) return;
    DiffUtil.scrollEditor(editor, line, false);
-    myCurrentSide = side;
+    setCurrentSide(side);
  }

  @Nullable
@@ -362,16 +356,16 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {

    @Override
    public void actionPerformed(@NotNull AnActionEvent e) {
-      if (myEditor1 == null || myEditor2 == null) return;
+      if (getEditor1() == null || getEditor2() == null) return;

      if (myScrollToPosition) {
-        EditorEx currentEditor = myCurrentSide.select(myEditor1, myEditor2);
-        EditorEx targetEditor = myCurrentSide.other().select(myEditor1, myEditor2);
-        LogicalPosition position = transferPosition(myCurrentSide, currentEditor.getCaretModel().getLogicalPosition());
+        EditorEx currentEditor = getCurrentSide().select(getEditor1(), getEditor2());
+        EditorEx targetEditor = getCurrentSide().other().select(getEditor1(), getEditor2());
+        LogicalPosition position = transferPosition(getCurrentSide(), currentEditor.getCaretModel().getLogicalPosition());
        targetEditor.getCaretModel().moveToLogicalPosition(position);
      }

-      myCurrentSide = myCurrentSide.other();
+      setCurrentSide(getCurrentSide().other());
      myPanel.requestFocus();
      getCurrentEditor().getScrollingModel().scrollToCaret(ScrollType.MAKE_VISIBLE);
    }
@@ -380,10 +374,10 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
  private class MyOpenInEditorWithMouseAction extends OpenInEditorWithMouseAction {
    @Override
    protected OpenFileDescriptor getDescriptor(@NotNull Editor editor, int line) {
-      if (editor != myEditor1 && editor != myEditor2) return null;
-      Side side = Side.fromLeft(editor == myEditor1);
+      if (editor != getEditor1() && editor != getEditor2()) return null;
+      Side side = Side.fromLeft(editor == getEditor1());

-      DocumentContent content = side.select(myActualContent1, myActualContent2);
+      DocumentContent content = side.select(getActualContent1(), getActualContent2());
      if (content == null) return null;

      int offset = editor.logicalPositionToOffset(new LogicalPosition(line, 0));
@@ -406,25 +400,12 @@ public abstract class TwosideTextDiffViewer extends TextDiffViewerBase {
      return getCurrentContent();
    }
    else if (CommonDataKeys.VIRTUAL_FILE.is(dataId)) {
-      return DiffUtil.getVirtualFile(myRequest, myCurrentSide);
+      return DiffUtil.getVirtualFile(myRequest, getCurrentSide());
    }

    return super.getData(dataId);
  }

-  private class MyEditorFocusListener extends FocusAdapter {
-    @NotNull private final Side mySide;
-
-    private MyEditorFocusListener(@NotNull Side side) {
-      mySide = side;
-    }
-
-    public void focusGained(FocusEvent e) {
-      if (myEditor1 == null || myEditor2 == null) return;
-      myCurrentSide = mySide;
-    }
-  }
-
  private class MyVisibleAreaListener implements VisibleAreaListener {
    @Override
    public void visibleAreaChanged(VisibleAreaEvent e) {
@@ -69,7 +69,7 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {
    myWrapperRequest = request;
    myDiffChanges = diffChanges;

-    assert myEditor1 != null && myEditor2 != null;
+    assert getEditor1() != null && getEditor2() != null;

    for (EditorEx editor : getEditors()) {
      EditorSettings settings = editor.getSettings();
@@ -90,8 +90,8 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {
    }

    for (DiffChange change : myDiffChanges) {
-      DiffDrawUtil.createBorderLineMarker(myEditor1, change.myEndLine1, SeparatorPlacement.TOP);
-      DiffDrawUtil.createBorderLineMarker(myEditor2, change.myEndLine2, SeparatorPlacement.TOP);
+      DiffDrawUtil.createBorderLineMarker(getEditor1(), change.myEndLine1, SeparatorPlacement.TOP);
+      DiffDrawUtil.createBorderLineMarker(getEditor2(), change.myEndLine2, SeparatorPlacement.TOP);
    }

    DiffSplitter splitter = myContentPanel.getSplitter();
@@ -146,10 +146,10 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {
    return new Runnable() {
      @Override
      public void run() {
-        assert myEditor1 != null && myEditor2 != null;
+        assert getEditor1() != null && getEditor2() != null;
        for (DiffChange change : myDiffChanges) {
-          setupHighlighting(myEditor1, change, Side.LEFT);
-          setupHighlighting(myEditor2, change, Side.RIGHT);
+          setupHighlighting(getEditor1(), change, Side.LEFT);
+          setupHighlighting(getEditor2(), change, Side.RIGHT);
        }
      }
    };
@@ -205,7 +205,7 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {

    @Override
    public void paint(@NotNull Graphics g, @NotNull JComponent divider) {
-      assert myEditor1 != null && myEditor2 != null;
+      assert getEditor1() != null && getEditor2() != null;
      Graphics2D gg = DiffDividerDrawUtil.getDividerGraphics(g, divider, getEditor1().getComponent());
      Rectangle clip = gg.getClipBounds();
      if (clip == null) return;
@@ -213,23 +213,23 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {
      gg.setColor(DiffDrawUtil.getDividerColor());
      gg.fill(clip);

-      JComponent header1 = myEditor1.getHeaderComponent();
-      JComponent header2 = myEditor2.getHeaderComponent();
+      JComponent header1 = getEditor1().getHeaderComponent();
+      JComponent header2 = getEditor2().getHeaderComponent();
      int headerOffset1 = header1 == null ? 0 : header1.getHeight();
      int headerOffset2 = header2 == null ? 0 : header2.getHeight();

      // TODO: painting is ugly if shift1 != shift2 (ex: search field is opened for one of editors)
-      int shift1 = myEditor1.getScrollingModel().getVerticalScrollOffset() - headerOffset1;
-      int shift2 = myEditor2.getScrollingModel().getVerticalScrollOffset() - headerOffset2;
+      int shift1 = getEditor1().getScrollingModel().getVerticalScrollOffset() - headerOffset1;
+      int shift2 = getEditor2().getScrollingModel().getVerticalScrollOffset() - headerOffset2;
      double rotate = shift1 == shift2 ? 0 : Math.atan2(shift2 - shift1, clip.width);

-      DiffDividerDrawUtil.paintPolygons(gg, divider.getWidth(), false, rotate == 0, myEditor1, myEditor2, this);
+      DiffDividerDrawUtil.paintPolygons(gg, divider.getWidth(), false, rotate == 0, getEditor1(), getEditor2(), this);

      for (DiffChange change : myDiffChanges) {
-        int y1 = myEditor1.logicalPositionToXY(new LogicalPosition(change.getStartLine(Side.LEFT), 0)).y - shift1;
-        int y2 = myEditor2.logicalPositionToXY(new LogicalPosition(change.getStartLine(Side.RIGHT), 0)).y - shift2;
-        int endY1 = myEditor1.logicalPositionToXY(new LogicalPosition(change.getEndLine(Side.LEFT), 0)).y - shift1;
-        int endY2 = myEditor2.logicalPositionToXY(new LogicalPosition(change.getEndLine(Side.RIGHT), 0)).y - shift2;
+        int y1 = getEditor1().logicalPositionToXY(new LogicalPosition(change.getStartLine(Side.LEFT), 0)).y - shift1;
+        int y2 = getEditor2().logicalPositionToXY(new LogicalPosition(change.getStartLine(Side.RIGHT), 0)).y - shift2;
+        int endY1 = getEditor1().logicalPositionToXY(new LogicalPosition(change.getEndLine(Side.LEFT), 0)).y - shift1;
+        int endY2 = getEditor2().logicalPositionToXY(new LogicalPosition(change.getEndLine(Side.RIGHT), 0)).y - shift2;

        AffineTransform oldTransform = gg.getTransform();
        gg.translate(0, y1);
@@ -261,7 +261,7 @@ public class SvnPropertiesDiffViewer extends TwosideTextDiffViewer {
        for (LineFragment fragment : diffChange.getFragments()) {
          if (!handler.process(Side.LEFT.getStartLine(fragment) + shift1, Side.LEFT.getEndLine(fragment) + shift1,
                               Side.RIGHT.getStartLine(fragment) + shift2, Side.RIGHT.getEndLine(fragment) + shift2,
-                               DiffUtil.getLineDiffType(fragment).getColor(myEditor1))) {
+                               DiffUtil.getLineDiffType(fragment).getColor(getEditor1()))) {
            return;
          }
        }