* Copyright 2010 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.

*/

* Constructs a GWT Java AST from a single isolated compilation unit. The AST is

* not associated with any {@link com.google.gwt.dev.jjs.ast.JProgram} and will

* contain unresolved references.

*/

  /**

   * Visit the JDT AST and produce our own AST. By the end of this pass, the

   * produced AST should contain every piece of information we'll ever need

   * about the code. The JDT nodes should never again be referenced after this.

   *

   * NOTE ON JDT FORCED OPTIMIZATIONS - If JDT statically determines that a

   * section of code in unreachable, it won't fully resolve that section of

   * code. This invalid-state code causes us major problems. As a result, we

   * have to optimize out those dead blocks early and never try to translate

   * them to our AST.

   */

  class AstVisitor extends SafeASTVisitor {

    /**

     * Collects JSNI references from native method bodies and replaces the ones referring to

     * compile time constants by their corresponding constant value.

     */

    private class JsniReferenceCollector extends JsModVisitor {

      private final GenerateJavaScriptLiterals generator = new GenerateJavaScriptLiterals();

      private final JsniMethodBody nativeMethodBody;

      private JsniReferenceCollector(JsniMethodBody nativeMethodBody) {

        this.nativeMethodBody = nativeMethodBody;

      }

      @Override

      public void endVisit(JsNameRef x, JsContext ctx) {

        if (!x.isJsniReference()) {

          return;

        }

        String ident = x.getIdent();

        Binding binding = jsniRefs.get(ident);

        SourceInfo info = x.getSourceInfo();

        assert binding != null;

        if (binding instanceof TypeBinding) {

          JType type = typeMap.get((TypeBinding) binding);

          processClassLiteral(x, info, type, ctx);

        } else if (binding instanceof FieldBinding) {

          FieldBinding fieldBinding = (FieldBinding) binding;

          /*

           * We must replace any compile-time constants with the constant

           * value of the field.

           */

          if (isCompileTimeConstant(fieldBinding)) {

            assert !ctx.isLvalue();

            JExpression constant = getConstant(info, fieldBinding.constant());

            generator.accept(constant);

            JsExpression result = generator.pop();

            assert (result != null);

            ctx.replaceMe(result);

          } else {

            // Normal: create a jsniRef.

            JField field = typeMap.get(fieldBinding);

            processField(x, info, field, ctx);

          }

        } else {

          JMethod method = typeMap.get((MethodBinding) binding);

          processMethod(x, info, method);

        }

      }

      private void processClassLiteral(JsNameRef nameRef, SourceInfo info, JType type,

          JsContext ctx) {

        assert !ctx.isLvalue();

        JsniClassLiteral classLiteral = new JsniClassLiteral(info, nameRef.getIdent(), type);