VCS: full, short diff: for addition/deletion, show only one diff panel

platform/platform-api/src/com/intellij/openapi/diff/DiffContent.java

@@ -32,6 +32,7 @@ import java.util.List;
  */
 public abstract class DiffContent {
   private final List<Listener> myListeners = ContainerUtil.createEmptyCOWList();
+  private boolean myIsEmpty;
 
   public void addListener(Listener listener) { myListeners.add(listener); }
   public void removeListener(Listener listener) { myListeners.remove(listener); }
@@ -52,6 +53,14 @@ public abstract class DiffContent {
    */
   public boolean isBinary() { return false; }
 
+  public void setIsEmpty(boolean isEmpty) {
+    myIsEmpty = isEmpty;
+  }
+
+  public boolean isEmpty() {
+    return myIsEmpty;
+  }
+
   /**
    * Called by {@link com.intellij.openapi.diff.DiffTool}
    * when document returned by {@link #getDocument()} is opened in editor. Implementors may use this notification to

platform/platform-api/src/com/intellij/openapi/diff/SimpleContent.java

@@ -67,6 +67,12 @@ public class SimpleContent extends DiffContent {
     myType = type;
   }
 
+  public static SimpleContent createEmpty() {
+    final SimpleContent content = new SimpleContent("");
+    content.setIsEmpty(true);
+    return content;
+  }
+
   /**
    * Make this content editable or not. By default SimpleContent isn't editable.
    */

platform/platform-impl/src/com/intellij/openapi/diff/impl/DiffPanelImpl.java

@@ -34,7 +34,7 @@ import com.intellij.openapi.diff.impl.fragments.Fragment;
 import com.intellij.openapi.diff.impl.fragments.FragmentList;
 import com.intellij.openapi.diff.impl.highlighting.DiffPanelState;
 import com.intellij.openapi.diff.impl.highlighting.FragmentSide;
-import com.intellij.openapi.diff.impl.processing.HorisontalDiffSplitter;
+import com.intellij.openapi.diff.impl.processing.HorizontalDiffSplitter;
 import com.intellij.openapi.diff.impl.splitter.DiffDividerPaint;
 import com.intellij.openapi.diff.impl.splitter.LineBlocks;
 import com.intellij.openapi.diff.impl.util.*;
@@ -131,7 +131,7 @@ public class DiffPanelImpl implements DiffPanelEx, ContentChangeListener, TwoSid
                                   new DiffDividerPaint(this, FragmentSide.SIDE1), myData);
     }
     else {
-      mySplitter = new HorisontalDiffSplitter(myLeftSide.getComponent(), myRightSide.getComponent());
+      mySplitter = new HorizontalDiffSplitter(myLeftSide.getComponent(), myRightSide.getComponent());
     }
 
     myPanel.insertDiffComponent(mySplitter.getComponent(), new MyScrollingPanel());
@@ -237,12 +237,28 @@ public class DiffPanelImpl implements DiffPanelEx, ContentChangeListener, TwoSid
     }
     myLeftSide.setHighlighterFactory(createHighlighter(types[0], baseFile, project));
     myRightSide.setHighlighterFactory(createHighlighter(types[1], baseFile, project));
+    setSplitterProportion(content1, content2);
     rediff();
     if (myIsRequestFocus) {
       myPanel.requestScrollEditors();
     }
   }
 
+  private void setSplitterProportion(DiffContent content1, DiffContent content2) {
+    if (content1.isEmpty()) {
+      mySplitter.setProportion(0f);
+      mySplitter.setResizeEnabled(false);
+      return;
+    }
+    if (content2.isEmpty()) {
+      mySplitter.setProportion(1.0f);
+      mySplitter.setResizeEnabled(false);
+      return;
+    }
+    mySplitter.setProportion(0.5f);
+    mySplitter.setResizeEnabled(true);
+  }
+
   public void removeStatusBar() {
     myPanel.removeStatusBar();
   }

platform/platform-impl/src/com/intellij/openapi/diff/impl/DiffSplitterI.java

@@ -32,4 +32,8 @@ public interface DiffSplitterI {
   VisibleAreaListener getVisibleAreaListener();
 
   JComponent getComponent();
+
+  void setProportion(final float proportion);
+
+  void setResizeEnabled(boolean value);
 }

platform/platform-impl/src/com/intellij/openapi/diff/impl/processing/HorizontalDiffSplitter.java

@@ -27,8 +27,8 @@ import javax.swing.*;
  * Date: 8/12/11
  * Time: 12:05 PM
  */
-public class HorisontalDiffSplitter extends Splitter implements DiffSplitterI {
-  public HorisontalDiffSplitter(final JComponent first, final JComponent second) {
+public class HorizontalDiffSplitter extends Splitter implements DiffSplitterI {
+  public HorizontalDiffSplitter(final JComponent first, final JComponent second) {
     super(true);
     setFirstComponent(first);
     setSecondComponent(second);
@@ -47,4 +47,16 @@ public class HorisontalDiffSplitter extends Splitter implements DiffSplitterI {
   public JComponent getComponent() {
     return this;
   }
+
+  @Override
+  public void setProportion(float proportion) {
+    super.setProportion(proportion);
+    // I regret to put this hack here
+    if (getFirstComponent() != null) {
+      getFirstComponent().setVisible(proportion > 0.0001f);
+    }
+    if (getSecondComponent() != null) {
+      getSecondComponent().setVisible(proportion < 0.9999f);
+    }
+  }
 }

platform/util/src/com/intellij/openapi/ui/Splitter.java

@@ -115,6 +115,10 @@ public class Splitter extends JPanel {
     setOrientation(myVerticalSplit);
   }
 
+  public void setResizeEnabled(final boolean value) {
+    myDivider.setResizeEnabled(value);
+  }
+
   public boolean isShowDividerIcon() {
     return myShowDividerIcon;
   }
@@ -591,6 +595,13 @@ public class Splitter extends JPanel {
 
     public void setResizeEnabled(boolean resizeEnabled) {
       myResizeEnabled = resizeEnabled;
+      if (! myResizeEnabled) {
+        setCursor(Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR));
+      } else {
+        setCursor(getOrientation() ?
+                  Cursor.getPredefinedCursor(Cursor.N_RESIZE_CURSOR) :
+                  Cursor.getPredefinedCursor(Cursor.W_RESIZE_CURSOR));
+      }
     }
   }
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/ChangesFragmentedDiffPanel.java

@@ -313,7 +313,7 @@ public class ChangesFragmentedDiffPanel implements Disposable {
   private void adjustPanelData(final DiffPanelImpl diffPanel) {
     final FragmentedDiffPanelState diffPanelState = (FragmentedDiffPanelState)diffPanel.getDiffPanelState();
     diffPanelState.setRanges(myFragmentedContent.getLineRanges());
-    diffPanel.setContents(new SimpleContent(myFragmentedContent.getSbOld().toString()), new SimpleContent(myFragmentedContent.getSbNew().toString()));
+    diffPanel.setContents(myFragmentedContent.createBeforeContent(), myFragmentedContent.createAfterContent());
     diffPanel.setLineNumberConvertors(myFragmentedContent.getOldConvertor(), myFragmentedContent.getNewConvertor());
     diffPanel.prefferedSizeByContents(-1);
   }
@@ -382,6 +382,8 @@ public class ChangesFragmentedDiffPanel implements Disposable {
     if (myFragmentedContent != null && ! Comparing.equal(myPresentationState, current)) {
       myFragmentedContent.recalculate();
       refreshData(myFragmentedContent);
+    } else {
+      ensurePresentation();
     }
     myPreviousDiff.registerCustomShortcutSet(myPreviousDiff.getShortcutSet(), myParent);
     myNextDiff.registerCustomShortcutSet(myNextDiff.getShortcutSet(), myParent);

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/FragmentedContent.java

@@ -30,6 +30,8 @@ public class FragmentedContent {
   private final Document myBefore;
   private final Document myAfter;
   private final List<BeforeAfter<TextRange>> myRanges;
+  private boolean myOneSide;
+  private boolean myIsAddition;
 
   public FragmentedContent(Document before, Document after, List<BeforeAfter<TextRange>> ranges) {
     myBefore = before;
@@ -54,6 +56,18 @@ public class FragmentedContent {
   }
 
   public boolean isOneSide() {
-    return myRanges.size() == 1 && (myRanges.get(0).getAfter().isEmpty() || myRanges.get(0).getBefore().isEmpty());
+    return myOneSide;
+  }
+
+  public void setOneSide(boolean oneSide) {
+    myOneSide = oneSide;
+  }
+
+  public boolean isAddition() {
+    return myIsAddition;
+  }
+
+  public void setIsAddition(boolean isAddition) {
+    myIsAddition = isAddition;
   }
 }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/FragmentedDiffRequestFromChange.java

@@ -28,6 +28,7 @@ import com.intellij.openapi.util.Pair;
 import com.intellij.openapi.util.TextRange;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.openapi.vcs.FilePath;
+import com.intellij.openapi.vcs.FileStatus;
 import com.intellij.openapi.vcs.VcsException;
 import com.intellij.openapi.vcs.changes.actions.ShowDiffAction;
 import com.intellij.openapi.vcs.ex.Range;
@@ -76,8 +77,11 @@ public class FragmentedDiffRequestFromChange {
     }
     List<BeforeAfter<TextRange>> ranges = calculator.getRanges();
     if (ranges == null || ranges.isEmpty()) return null;
-    final PreparedFragmentedContent preparedFragmentedContent =
-      new PreparedFragmentedContent(myProject, new FragmentedContent(calculator.getOldDocument(), calculator.getDocument(), ranges),
+    FragmentedContent fragmentedContent = new FragmentedContent(calculator.getOldDocument(), calculator.getDocument(), ranges);
+    final FileStatus fs = change.getFileStatus();
+    fragmentedContent.setIsAddition(FileStatus.ADDED.equals(fs));
+    fragmentedContent.setOneSide(FileStatus.ADDED.equals(fs) || FileStatus.DELETED.equals(fs));
+    final PreparedFragmentedContent preparedFragmentedContent = new PreparedFragmentedContent(myProject, fragmentedContent,
                                     filePath.getName(), filePath.getFileType());
     VirtualFile file = filePath.getVirtualFile();
     if (file == null) {

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/PreparedFragmentedContent.java

@@ -15,6 +15,8 @@
  */
 package com.intellij.openapi.vcs.changes;
 
+import com.intellij.openapi.diff.DiffContent;
+import com.intellij.openapi.diff.SimpleContent;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.colors.EditorColorsManager;
 import com.intellij.openapi.editor.highlighter.*;
@@ -48,6 +50,7 @@ public class PreparedFragmentedContent {
   private List<TextRange> myAfterFragments;
   private List<BeforeAfter<Integer>> myLineRanges;
   private boolean myOneSide;
+  private boolean myIsAddition;
 
   private FragmentedEditorHighlighter myBeforeHighlighter;
   private FragmentedEditorHighlighter myAfterHighlighter;
@@ -88,6 +91,7 @@ public class PreparedFragmentedContent {
 
   private void fromFragmentedContent(final FragmentedContent fragmentedContent) {
     myOneSide = fragmentedContent.isOneSide();
+    myIsAddition = fragmentedContent.isAddition();
     List<BeforeAfter<TextRange>> expandedRanges =
       expand(fragmentedContent.getRanges(), VcsConfiguration.getInstance(myProject).SHORT_DIFF_EXTRA_LINES,
              fragmentedContent.getBefore(), fragmentedContent.getAfter());
@@ -145,6 +149,20 @@ public class PreparedFragmentedContent {
     return newConvertor;
   }
 
+  public DiffContent createBeforeContent() {
+    if (isAddition()) {
+      return SimpleContent.createEmpty();
+    }
+    return new SimpleContent(getSbOld().toString());
+  }
+
+  public DiffContent createAfterContent() {
+    if (isDeletion()) {
+      return SimpleContent.createEmpty();
+    }
+    return new SimpleContent(getSbNew().toString());
+  }
+
   public StringBuilder getSbOld() {
     return sbOld;
   }
@@ -169,6 +187,14 @@ public class PreparedFragmentedContent {
     return myOneSide;
   }
 
+  public boolean isAddition() {
+    return myOneSide && myIsAddition;
+  }
+
+  public boolean isDeletion() {
+    return myOneSide && ! myIsAddition;
+  }
+
   public FragmentedEditorHighlighter getBeforeHighlighter() {
     return myBeforeHighlighter;
   }

platform/vcs-impl/src/com/intellij/openapi/vcs/changes/actions/ChangeDiffRequestPresentable.java

@@ -126,7 +126,7 @@ public class ChangeDiffRequestPresentable implements DiffRequestPresentable {
   @NotNull
   private DiffContent createContent(final ContentRevision revision) {
     ProgressManager.checkCanceled();
-    if (revision == null) return new SimpleContent("");
+    if (revision == null) return SimpleContent.createEmpty();
     if (revision instanceof CurrentContentRevision) {
       final CurrentContentRevision current = (CurrentContentRevision)revision;
       final VirtualFile vFile = current.getVirtualFile();