2.1/dev/core/src/com/google/gwt/dev/jjs/impl/CloneExpressionVisitor.java

/*
 * Copyright 2008 Google Inc.
 * 
 * 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.google.gwt.dev.jjs.impl;

import com.google.gwt.dev.jjs.InternalCompilerException;
import com.google.gwt.dev.jjs.ast.Context;
import com.google.gwt.dev.jjs.ast.JAbsentArrayDimension;
import com.google.gwt.dev.jjs.ast.JArrayLength;
import com.google.gwt.dev.jjs.ast.JArrayRef;
import com.google.gwt.dev.jjs.ast.JBinaryOperation;
import com.google.gwt.dev.jjs.ast.JBooleanLiteral;
import com.google.gwt.dev.jjs.ast.JCastOperation;
import com.google.gwt.dev.jjs.ast.JCharLiteral;
import com.google.gwt.dev.jjs.ast.JClassLiteral;
import com.google.gwt.dev.jjs.ast.JConditional;
import com.google.gwt.dev.jjs.ast.JDoubleLiteral;
import com.google.gwt.dev.jjs.ast.JExpression;
import com.google.gwt.dev.jjs.ast.JFieldRef;
import com.google.gwt.dev.jjs.ast.JFloatLiteral;
import com.google.gwt.dev.jjs.ast.JGwtCreate;
import com.google.gwt.dev.jjs.ast.JInstanceOf;
import com.google.gwt.dev.jjs.ast.JIntLiteral;
import com.google.gwt.dev.jjs.ast.JLocalRef;
import com.google.gwt.dev.jjs.ast.JLongLiteral;
import com.google.gwt.dev.jjs.ast.JMethodCall;
import com.google.gwt.dev.jjs.ast.JNameOf;
import com.google.gwt.dev.jjs.ast.JNewArray;
import com.google.gwt.dev.jjs.ast.JNewInstance;
import com.google.gwt.dev.jjs.ast.JNullLiteral;
import com.google.gwt.dev.jjs.ast.JParameterRef;
import com.google.gwt.dev.jjs.ast.JPostfixOperation;
import com.google.gwt.dev.jjs.ast.JPrefixOperation;
import com.google.gwt.dev.jjs.ast.JStringLiteral;
import com.google.gwt.dev.jjs.ast.JThisRef;
import com.google.gwt.dev.jjs.ast.JVisitor;
import com.google.gwt.dev.jjs.ast.js.JMultiExpression;
import com.google.gwt.dev.jjs.ast.js.JsniFieldRef;
import com.google.gwt.dev.jjs.ast.js.JsniMethodRef;

import java.util.ArrayList;
import java.util.List;

/**
 * A general purpose expression cloner.
 */
public class CloneExpressionVisitor extends JVisitor {
  private JExpression expression;

  public CloneExpressionVisitor() {
  }

  @SuppressWarnings("unchecked")
  public <T extends JExpression> T cloneExpression(T expr) {
    if (expr == null) {
      return null;
    }

    // double check that the expression is successfully cloned
    expression = null;

    this.accept(expr);

    if (expression == null) {
      throw new InternalCompilerException(expr, "Unable to clone expression",
          null);
    }

    Class<T> originalClass = (Class<T>) expr.getClass();
    return originalClass.cast(expression);
  }

  public ArrayList<JExpression> cloneExpressions(List<JExpression> exprs) {
    if (exprs == null) {
      return null;
    }
    ArrayList<JExpression> result = new ArrayList<JExpression>();
    for (JExpression expr : exprs) {
      result.add(cloneExpression(expr));
    }
    return result;
  }

  @Override
  public boolean visit(JAbsentArrayDimension x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JArrayLength x, Context ctx) {
    expression = new JArrayLength(x.getSourceInfo(), cloneExpression(
        x.getInstance()));
    return false;
  }

  @Override
  public boolean visit(JArrayRef x, Context ctx) {
    expression = new JArrayRef(x.getSourceInfo(),
        cloneExpression(x.getInstance()), cloneExpression(x.getIndexExpr()));
    return false;
  }

  @Override
  public boolean visit(JBinaryOperation x, Context ctx) {
    expression = new JBinaryOperation(x.getSourceInfo(), x.getType(),
        x.getOp(), cloneExpression(x.getLhs()), cloneExpression(x.getRhs()));
    return false;
  }

  @Override
  public boolean visit(JBooleanLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JCastOperation x, Context ctx) {
    expression = new JCastOperation(x.getSourceInfo(), x.getCastType(),
        cloneExpression(x.getExpr()));
    return false;
  }

  @Override
  public boolean visit(JCharLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JClassLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JConditional x, Context ctx) {
    expression = new JConditional(x.getSourceInfo(), x.getType(),
        cloneExpression(x.getIfTest()), cloneExpression(x.getThenExpr()),
        cloneExpression(x.getElseExpr()));
    return false;
  }

  @Override
  public boolean visit(JDoubleLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JFieldRef x, Context ctx) {
    expression = new JFieldRef(x.getSourceInfo(),
        cloneExpression(x.getInstance()), x.getField(), x.getEnclosingType());
    return false;
  }

  @Override
  public boolean visit(JFloatLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JGwtCreate x, Context ctx) {
    // Clone the internal instantiation expressions directly.
    ArrayList<JExpression> clonedExprs = new ArrayList<JExpression>();
    for (JExpression expr : x.getInstantiationExpressions()) {
      clonedExprs.add(cloneExpression(expr));
    }

    // Use the clone constructor.
    JGwtCreate gwtCreate = new JGwtCreate(x.getSourceInfo(), x.getSourceType(),
        x.getResultTypes(), x.getType(),
        cloneExpressions(x.getInstantiationExpressions()));

    expression = gwtCreate;
    return false;
  }

  @Override
  public boolean visit(JInstanceOf x, Context ctx) {
    expression = new JInstanceOf(x.getSourceInfo(), x.getTestType(),
        cloneExpression(x.getExpr()));
    return false;
  }

  @Override
  public boolean visit(JIntLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JLocalRef x, Context ctx) {
    expression = new JLocalRef(x.getSourceInfo(), x.getLocal());
    return false;
  }

  @Override
  public boolean visit(JLongLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JMethodCall x, Context ctx) {
    JMethodCall newMethodCall = new JMethodCall(x,
        cloneExpression(x.getInstance()));
    newMethodCall.addArgs(cloneExpressions(x.getArgs()));
    expression = newMethodCall;
    return false;
  }

  @Override
  public boolean visit(JMultiExpression x, Context ctx) {
    JMultiExpression multi = new JMultiExpression(x.getSourceInfo());
    multi.exprs.addAll(cloneExpressions(x.exprs));
    expression = multi;
    return false;
  }

  @Override
  public boolean visit(JNameOf x, Context ctx) {
    expression = new JNameOf(x.getSourceInfo(), x.getType(), x.getNode());
    return false;
  }

  @Override
  public boolean visit(JNewArray x, Context ctx) {
    expression = new JNewArray(x.getSourceInfo(), x.getType(),
        cloneExpressions(x.dims), cloneExpressions(x.initializers),
        x.getClassLiterals());
    return false;
  }

  @Override
  public boolean visit(JNewInstance x, Context ctx) {
    JNewInstance newInstance = new JNewInstance(x);
    newInstance.addArgs(cloneExpressions(x.getArgs()));
    expression = newInstance;
    return false;
  }

  @Override
  public boolean visit(JNullLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JParameterRef x, Context ctx) {
    expression = new JParameterRef(x.getSourceInfo(), x.getParameter());
    return false;
  }

  @Override
  public boolean visit(JPostfixOperation x, Context ctx) {
    expression = new JPostfixOperation(x.getSourceInfo(), x.getOp(),
        cloneExpression(x.getArg()));
    return false;
  }

  @Override
  public boolean visit(JPrefixOperation x, Context ctx) {
    expression = new JPrefixOperation(x.getSourceInfo(), x.getOp(),
        cloneExpression(x.getArg()));
    return false;
  }

  @Override
  public boolean visit(JsniFieldRef x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JsniMethodRef x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JStringLiteral x, Context ctx) {
    expression = x;
    return false;
  }

  @Override
  public boolean visit(JThisRef x, Context ctx) {
    expression = new JThisRef(x.getSourceInfo(), x.getType());
    return false;
  }
}