content: package act.view.rythm;
  
  /*-
   * #%L
   * ACT Framework
   * %%
   * Copyright (C) 2014 - 2017 ActFramework
   * %%
   * 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.
   * #L%
   */
  
  import act.Act;
  import act.app.App;
  import act.app.AppByteCodeScannerBase;
  import act.app.event.SysEventId;
  import act.asm.*;
  import act.util.AsmTypes;
  import act.util.ByteCodeVisitor;
  import org.osgl.util.S;
  import org.rythmengine.extension.Transformer;
  
  /**
   * Search for method that has {@link org.rythmengine.extension.Transformer} annotation.
   * Register the class if such method found
   */
  public class RythmTransformerScanner extends AppByteCodeScannerBase {
  
      private static final String TRANSFORMER = Transformer.class.getName();
  
      @Override
      protected boolean shouldScan(String className) {
          return true;
      }
  
      @Override
      public ByteCodeVisitor byteCodeVisitor() {
          return new Visitor();
      }
  
      @Override
      public void scanFinished(String className) {
      }
  
      private class Visitor extends ByteCodeVisitor {
  
          boolean found;
          String className;
  
          @Override
          public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
              super.visit(version, access, name, signature, superName, interfaces);
              if (!AsmTypes.isPublic(access)) {
                  return;
              }
              className = Type.getObjectType(name).getClassName();
          }
  
          @Override
          public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
              if (!found) {
                  String className = Type.getType(desc).getClassName();
                  if (S.eq(TRANSFORMER, className)) {
                      found = true;
                  }
              }
              return super.visitAnnotation(desc, visible);
          }
  
          @Override
          public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
              MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
              if (found) {
                  return mv;
              }
              return new MethodVisitor(ASM5, mv) {
                  @Override
                  public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                      if (!found) {
                          String className = Type.getType(desc).getClassName();
                          if (S.eq(TRANSFORMER, className)) {
                              found = true;
                          }
                      }
                      return super.visitAnnotation(desc, visible);
                  }
              };
          }
  
          @Override
          public void visitEnd() {
              super.visitEnd();
              if (found) {
                  final App app = app();
                  app().jobManager().on(SysEventId.PRE_START, "RythmTransformerScanner:registerTransformer:" + className, new Runnable() {
                      @Override
                      public void run() {
                          RythmView rythmView = (RythmView) Act.viewManager().view(RythmView.ID);
                          rythmView.registerTransformer(app(), app.classForName(className));
                      }
                  });
              }
          }
      }
  }
  