Initial implementation of "Rename Local Variable" refactoring.

editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/correction/QuickAssistLightBulbUpdater.java

Index: editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/correction/QuickAssistLightBulbUpdater.java
diff --git a/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/correction/QuickAssistLightBulbUpdater.java b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/correction/QuickAssistLightBulbUpdater.java
new file mode 100644
index 0000000000000000000000000000000000000000..63b4cde2e19bb001f5ab217a2018beec956a212a
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/ui/internal/text/correction/QuickAssistLightBulbUpdater.java
@@ -0,0 +1,269 @@
+package com.google.dart.tools.ui.internal.text.correction;
+
+import com.google.dart.compiler.ast.DartUnit;
+import com.google.dart.tools.core.model.CompilationUnit;
+import com.google.dart.tools.core.model.DartElement;
+import com.google.dart.tools.ui.DartPluginImages;
+import com.google.dart.tools.ui.DartUI;
+import com.google.dart.tools.ui.PreferenceConstants;
+import com.google.dart.tools.ui.internal.text.editor.ASTProvider;
+import com.google.dart.tools.ui.internal.viewsupport.ISelectionListenerWithAST;
+import com.google.dart.tools.ui.internal.viewsupport.SelectionListenerWithASTManager;
+import com.google.dart.tools.ui.text.dart.IInvocationContext;
+
+import org.eclipse.jface.text.IDocument;
+import org.eclipse.jface.text.ITextViewer;
+import org.eclipse.jface.text.source.Annotation;
+import org.eclipse.jface.text.source.IAnnotationAccessExtension;
+import org.eclipse.jface.text.source.IAnnotationModel;
+import org.eclipse.jface.text.source.IAnnotationPresentation;
+import org.eclipse.jface.text.source.ImageUtilities;
+import org.eclipse.jface.util.IPropertyChangeListener;
+import org.eclipse.jface.util.PropertyChangeEvent;
+import org.eclipse.swt.SWT;
+import org.eclipse.swt.graphics.GC;
+import org.eclipse.swt.graphics.Image;
+import org.eclipse.swt.graphics.Point;
+import org.eclipse.swt.graphics.Rectangle;
+import org.eclipse.swt.widgets.Canvas;
+import org.eclipse.ui.editors.text.EditorsUI;
+import org.eclipse.ui.texteditor.AnnotationPreference;
+import org.eclipse.ui.texteditor.ITextEditor;
+
+/**
+ *
+ */
+public class QuickAssistLightBulbUpdater {
+
+  public static class AssistAnnotation extends Annotation implements IAnnotationPresentation {
+
+    //XXX: To be fully correct this should be a non-static fields in QuickAssistLightBulbUpdater
+    private static final int LAYER;
+
+    static {
+      Annotation annotation = new Annotation("org.eclipse.jdt.ui.warning", false, null); //$NON-NLS-1$
+      AnnotationPreference preference = EditorsUI.getAnnotationPreferenceLookup().getAnnotationPreference(
+          annotation);
+      if (preference != null) {
+        LAYER = preference.getPresentationLayer() - 1;
+      } else {
+        LAYER = IAnnotationAccessExtension.DEFAULT_LAYER;
+      }
+
+    }
+
+    private Image fImage;
+
+    public AssistAnnotation() {
+    }
+
+    @Override
+    public int getLayer() {
+      return LAYER;
+    }
+
+    @Override
+    public void paint(GC gc, Canvas canvas, Rectangle r) {
+      ImageUtilities.drawImage(getImage(), gc, canvas, r, SWT.CENTER, SWT.TOP);
+    }
+
+    private Image getImage() {
+      if (fImage == null) {
+        fImage = DartPluginImages.get(DartPluginImages.IMG_OBJS_QUICK_ASSIST);
+      }
+      return fImage;
+    }
+
+  }
+
+  private final Annotation fAnnotation;
+  private boolean fIsAnnotationShown;
+  private final ITextEditor fEditor;
+  private final ITextViewer fViewer;
+
+  private ISelectionListenerWithAST fListener;
+  private IPropertyChangeListener fPropertyChangeListener;
+
+  public QuickAssistLightBulbUpdater(ITextEditor part, ITextViewer viewer) {
+    fEditor = part;
+    fViewer = viewer;
+    fAnnotation = new AssistAnnotation();
+    fIsAnnotationShown = false;
+    fPropertyChangeListener = null;
+  }
+
+  public void install() {
+    if (isSetInPreferences()) {
+      installSelectionListener();
+    }
+    if (fPropertyChangeListener == null) {
+      fPropertyChangeListener = new IPropertyChangeListener() {
+        @Override
+        public void propertyChange(PropertyChangeEvent event) {
+          doPropertyChanged(event.getProperty());
+        }
+      };
+      PreferenceConstants.getPreferenceStore().addPropertyChangeListener(fPropertyChangeListener);
+    }
+  }
+
+  public boolean isSetInPreferences() {
+    return PreferenceConstants.getPreferenceStore().getBoolean(
+        PreferenceConstants.EDITOR_QUICKASSIST_LIGHTBULB);
+  }
+
+  public void uninstall() {
+    uninstallSelectionListener();
+    if (fPropertyChangeListener != null) {
+      PreferenceConstants.getPreferenceStore().removePropertyChangeListener(fPropertyChangeListener);
+      fPropertyChangeListener = null;
+    }
+  }
+
+  protected void doPropertyChanged(String property) {
+    if (property.equals(PreferenceConstants.EDITOR_QUICKASSIST_LIGHTBULB)) {
+      if (isSetInPreferences()) {
+        CompilationUnit cu = getCompilationUnit();
+        if (cu != null) {
+          installSelectionListener();
+          Point point = fViewer.getSelectedRange();
+          DartUnit astRoot = ASTProvider.getASTProvider().getAST(cu, ASTProvider.WAIT_ACTIVE_ONLY,
+              null);
+          if (astRoot != null) {
+            doSelectionChanged(point.x, point.y, astRoot);
+          }
+        }
+      } else {
+        uninstallSelectionListener();
+      }
+    }
+  }
+
+  /*
+   * Needs to be called synchronized
+   */
+  private void calculateLightBulb(IAnnotationModel model, IInvocationContext context) {
+    // TODO(scheglov) restore this later
+//    boolean needsAnnotation = DartCorrectionProcessor.hasAssists(context);
+//    if (fIsAnnotationShown) {
+//      model.removeAnnotation(fAnnotation);
+//    }
+//    if (needsAnnotation) {
+//      model.addAnnotation(fAnnotation,
+//          new Position(context.getSelectionOffset(), context.getSelectionLength()));
+//    }
+//    fIsAnnotationShown = needsAnnotation;
+  }
+
+  private void doSelectionChanged(int offset, int length, DartUnit astRoot) {
+
+    final IAnnotationModel model = getAnnotationModel();
+    final CompilationUnit cu = getCompilationUnit();
+    if (model == null || cu == null) {
+      return;
+    }
+
+    final AssistContext context = new AssistContext(cu, offset, length);
+    context.setASTRoot(astRoot);
+
+    boolean hasQuickFix = hasQuickFixLightBulb(model, context.getSelectionOffset());
+    if (hasQuickFix) {
+      removeLightBulb(model);
+      return; // there is already a quick fix light bulb at the new location
+    }
+
+    calculateLightBulb(model, context);
+  }
+
+  private IAnnotationModel getAnnotationModel() {
+    return DartUI.getDocumentProvider().getAnnotationModel(fEditor.getEditorInput());
+  }
+
+  private CompilationUnit getCompilationUnit() {
+    DartElement elem = DartUI.getEditorInputDartElement(fEditor.getEditorInput());
+    if (elem instanceof CompilationUnit) {
+      return (CompilationUnit) elem;
+    }
+    return null;
+  }
+
+  private IDocument getDocument() {
+    return DartUI.getDocumentProvider().getDocument(fEditor.getEditorInput());
+  }
+
+  /**
+   * Tests if there is already a quick fix light bulb on the current line
+   */
+  private boolean hasQuickFixLightBulb(IAnnotationModel model, int offset) {
+    // TODO(scheglov) restore this later
+//    try {
+//      IDocument document = getDocument();
+//      if (document == null) {
+//        return false;
+//      }
+//
+//      // we access a document and annotation model from within a job
+//      // since these are only read accesses, we won't hurt anyone else if
+//      // this goes boink
+//
+//      // may throw an IndexOutOfBoundsException upon concurrent document modification
+//      int currLine = document.getLineOfOffset(offset);
+//
+//      // this iterator is not protected, it may throw ConcurrentModificationExceptions
+//      Iterator<Annotation> iter = model.getAnnotationIterator();
+//      while (iter.hasNext()) {
+//        Annotation annot = iter.next();
+//        if (DartCorrectionProcessor.isQuickFixableType(annot)) {
+//          // may throw an IndexOutOfBoundsException upon concurrent annotation model changes
+//          Position pos = model.getPosition(annot);
+//          if (pos != null) {
+//            // may throw an IndexOutOfBoundsException upon concurrent document modification
+//            int startLine = document.getLineOfOffset(pos.getOffset());
+//            if (startLine == currLine && DartCorrectionProcessor.hasCorrections(annot)) {
+//              return true;
+//            }
+//          }
+//        }
+//      }
+//    } catch (BadLocationException e) {
+//      // ignore
+//    } catch (IndexOutOfBoundsException e) {
+//      // concurrent modification - too bad, ignore
+//    } catch (ConcurrentModificationException e) {
+//      // concurrent modification - too bad, ignore
+//    }
+    return false;
+  }
+
+  private void installSelectionListener() {
+    // TODO(scheglov) restore this later
+//    fListener = new ISelectionListenerWithAST() {
+//      public void selectionChanged(IEditorPart part, ITextSelection selection,
+//          CompilationUnit astRoot) {
+//        doSelectionChanged(selection.getOffset(), selection.getLength(), astRoot);
+//      }
+//    };
+//    SelectionListenerWithASTManager.getDefault().addListener(fEditor, fListener);
+  }
+
+  private void removeLightBulb(IAnnotationModel model) {
+    synchronized (this) {
+      if (fIsAnnotationShown) {
+        model.removeAnnotation(fAnnotation);
+        fIsAnnotationShown = false;
+      }
+    }
+  }
+
+  private void uninstallSelectionListener() {
+    if (fListener != null) {
+      SelectionListenerWithASTManager.getDefault().removeListener(fEditor, fListener);
+      fListener = null;
+    }
+    IAnnotationModel model = getAnnotationModel();
+    if (model != null) {
+      removeLightBulb(model);
+    }
+  }
+
+}