Initial support for 'Extract temp' - only when single expression selected

editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/code/ExtractLocalRefactoring.java

Index: editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/code/ExtractLocalRefactoring.java
diff --git a/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/code/ExtractLocalRefactoring.java b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/code/ExtractLocalRefactoring.java
new file mode 100644
index 0000000000000000000000000000000000000000..fc23431a3bd477d5b71f1b4de40f87ead5f83593
--- /dev/null
+++ b/editor/tools/plugins/com.google.dart.tools.ui/src/com/google/dart/tools/internal/corext/refactoring/code/ExtractLocalRefactoring.java
@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2012, the Dart project authors.
+ * 
+ * Licensed under the Eclipse Public License v1.0 (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.eclipse.org/legal/epl-v10.html
+ * 
+ * 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.google.dart.tools.internal.corext.refactoring.code;
+
+import com.google.dart.compiler.ast.DartExpression;
+import com.google.dart.compiler.ast.DartNode;
+import com.google.dart.compiler.ast.DartStatement;
+import com.google.dart.compiler.ast.DartUnit;
+import com.google.dart.tools.core.buffer.Buffer;
+import com.google.dart.tools.core.internal.model.SourceRangeImpl;
+import com.google.dart.tools.core.model.CompilationUnit;
+import com.google.dart.tools.core.model.DartModelException;
+import com.google.dart.tools.core.model.SourceRange;
+import com.google.dart.tools.core.refactoring.CompilationUnitChange;
+import com.google.dart.tools.core.utilities.compiler.DartCompilerUtilities;
+import com.google.dart.tools.internal.corext.dom.ASTNodes;
+import com.google.dart.tools.internal.corext.refactoring.RefactoringCoreMessages;
+import com.google.dart.tools.ui.internal.text.Selection;
+import com.google.dart.tools.ui.internal.text.SelectionAnalyzer;
+
+import org.eclipse.core.runtime.Assert;
+import org.eclipse.core.runtime.CoreException;
+import org.eclipse.core.runtime.IProgressMonitor;
+import org.eclipse.core.runtime.SubProgressMonitor;
+import org.eclipse.ltk.core.refactoring.Change;
+import org.eclipse.ltk.core.refactoring.Refactoring;
+import org.eclipse.ltk.core.refactoring.RefactoringStatus;
+import org.eclipse.text.edits.MultiTextEdit;
+import org.eclipse.text.edits.ReplaceEdit;
+import org.eclipse.text.edits.TextEdit;
+import org.eclipse.text.edits.TextEditGroup;
+
+/**
+ * Extract Local Variable (from selected expression inside method or initializer).
+ * 
+ * @coverage dart.editor.ui.refactoring.core
+ */
+public class ExtractLocalRefactoring extends Refactoring {
+
+  private final CompilationUnit unit;
+  private final int selectionLength;
+  private final int selectionStart;
+  private final SourceRange selectionRange;
+
+  private final CompilationUnitChange change;
+  private Buffer buffer;
+  private DartUnit unitNode;
+  private String localName;
+
+  private String[] guessedNames;
+  private SelectionAnalyzer selectionAnalyzer;
+
+  public ExtractLocalRefactoring(CompilationUnit unit, int selectionStart, int selectionLength) {
+    Assert.isTrue(selectionStart >= 0);
+    Assert.isTrue(selectionLength >= 0);
+    this.unit = unit;
+    this.selectionStart = selectionStart;
+    this.selectionLength = selectionLength;
+    this.selectionRange = new SourceRangeImpl(selectionStart, selectionLength);
+    change = new CompilationUnitChange(unit.getElementName(), unit);
+    localName = ""; //$NON-NLS-1$
+  }
+
+  @Override
+  public RefactoringStatus checkFinalConditions(IProgressMonitor pm) throws CoreException {
+    try {
+      pm.beginTask(RefactoringCoreMessages.ExtractLocalRefactoring_checking_preconditions, 4);
+      RefactoringStatus result = new RefactoringStatus();
+      // XXX
+      MultiTextEdit rootEdit = new MultiTextEdit();
+      change.setEdit(rootEdit);
+      change.setKeepPreviewEdits(true);
+      // add variable declaration
+      if (ExtractUtils.isSingleNodeSelected(selectionAnalyzer, selectionRange, unit)) {
+        DartNode selectedNode = selectionAnalyzer.getFirstSelectedNode();
+        if (selectedNode instanceof DartExpression) {
+          DartExpression expression = (DartExpression) selectedNode;
+          // prepare expression type
+          String typeSource = ExtractUtils.getTypeSource(expression);
+          if (typeSource == null || typeSource.equals("Dynamic")) {
+            typeSource = "var";
+          }
+          // prepare variable declaration source
+          String initializerSource = buffer.getText(selectionStart, selectionLength);
+          String declarationSource = typeSource + " " + localName + " = " + initializerSource + ";";
+          // prepare location for declaration
+          DartStatement parentStatement = ASTNodes.getParent(selectedNode, DartStatement.class);
+          String prefix = ExtractUtils.getNodePrefix(buffer, parentStatement);
+          // insert variable declaration
+          String eol = getEol();
+          TextEdit edit = new ReplaceEdit(
+              parentStatement.getSourceInfo().getOffset(),
+              0,
+              declarationSource + eol + prefix);
+          rootEdit.addChild(edit);
+          change.addTextEditGroup(new TextEditGroup(
+              RefactoringCoreMessages.ExtractLocalRefactoring_declare_local_variable,
+              edit));
+        }
+      }
+      // TODO(scheglov) more cases
+      // replace selection with variable reference
+      {
+        TextEdit edit = new ReplaceEdit(selectionStart, selectionLength, localName);
+        rootEdit.addChild(edit);
+        change.addTextEditGroup(new TextEditGroup(
+            RefactoringCoreMessages.ExtractLocalRefactoring_replace,
+            edit));
+      }
+      // done
+      return result;
+    } finally {
+      pm.done();
+    }
+  }
+
+  @Override
+  public RefactoringStatus checkInitialConditions(IProgressMonitor pm) throws CoreException {
+    try {
+      pm.beginTask("", 4); //$NON-NLS-1$
+      RefactoringStatus result = new RefactoringStatus();
+      // prepare AST
+      buffer = unit.getBuffer();
+      unitNode = DartCompilerUtilities.resolveUnit(unit);
+      pm.worked(1);
+      // check selection
+      result.merge(checkSelection(new SubProgressMonitor(pm, 3)));
+      // done
+      return result;
+    } finally {
+      pm.done();
+    }
+  }
+
+  public RefactoringStatus checkLocalName(String newName) {
+    return new RefactoringStatus();
+    // TODO(scheglov)
+//    RefactoringStatus status = Checks.checkTempName(newName, fCu);
+//    if (Arrays.asList(getExcludedVariableNames()).contains(newName)) {
+//      status.addWarning(Messages.format(
+//          RefactoringCoreMessages.ExtractTempRefactoring_another_variable,
+//          newName));
+//    }
+//    return status;
+  }
+
+  @Override
+  public Change createChange(IProgressMonitor pm) throws CoreException {
+    try {
+      pm.beginTask(RefactoringCoreMessages.ExtractLocalRefactoring_checking_preconditions, 1);
+      return change;
+    } finally {
+      pm.done();
+    }
+  }
+
+  @Override
+  public String getName() {
+    return RefactoringCoreMessages.ExtractLocalRefactoring_name;
+  }
+
+  /**
+   * @return proposed variable names (may be empty, but not null). The first proposal should be used
+   *         as "best guess" (if it exists).
+   */
+  public String[] guessNames() {
+    if (guessedNames == null) {
+      // TODO(scheglov)
+//      try {
+//        DartExpression expression = getSelectedExpression().getAssociatedExpression();
+//        if (expression != null) {
+//          ITypeBinding binding = guessBindingForReference(expression);
+//          fGuessedTempNames = StubUtility.getVariableNameSuggestions(
+//              NamingConventions.VK_LOCAL,
+//              fCu.getDartProject(),
+//              binding,
+//              expression,
+//              Arrays.asList(getExcludedVariableNames()));
+//        }
+//      } catch (DartModelException e) {
+//      }
+      if (guessedNames == null) {
+        guessedNames = new String[0];
+      }
+    }
+    return guessedNames;
+  }
+
+  public boolean replaceAllOccurrences() {
+    // TODO(scheglov)
+    return false;
+//    return fReplaceAllOccurrences;
+  }
+
+  public void setLocalName(String newName) {
+    localName = newName;
+  }
+
+  public void setReplaceAllOccurrences(boolean replaceAllOccurrences) {
+    // TODO(scheglov)
+    //fReplaceAllOccurrences = replaceAllOccurrences;
+  }
+
+  private RefactoringStatus checkSelection(IProgressMonitor pm) throws DartModelException {
+    Selection selection = Selection.createFromStartLength(
+        selectionRange.getOffset(),
+        selectionRange.getLength());
+    selectionAnalyzer = new SelectionAnalyzer(selection, false);
+    unitNode.accept(selectionAnalyzer);
+    // TODO(scheglov)
+    if (!ExtractUtils.isSingleNodeSelected(selectionAnalyzer, selectionRange, unit)) {
+      return RefactoringStatus.createFatalErrorStatus(RefactoringCoreMessages.ExtractLocalRefactoring_select_expression);
+    }
+    return new RefactoringStatus();
+  }
+
+  private String getEol() {
+    // TODO(scheglov) prepare from Buffer and cache
+    return ExtractUtils.DEFAULT_END_OF_LINE;
+  }
+}