content: package act.event.bytecode;
  
  /*-
   * #%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.app.AppByteCodeScannerBase;
  import act.app.event.SysEventId;
  import act.asm.AnnotationVisitor;
  import act.asm.MethodVisitor;
  import act.asm.Type;
  import act.event.*;
  import act.event.meta.SimpleEventListenerMetaInfo;
  import act.job.JobManager;
  import act.util.*;
  import org.osgl.$;
  import org.osgl.exception.NotAppliedException;
  import org.osgl.util.S;
  
  import java.lang.annotation.Annotation;
  import java.lang.reflect.Modifier;
  import java.util.ArrayList;
  import java.util.List;
  
  public class SimpleEventListenerByteCodeScanner extends AppByteCodeScannerBase {
  
      private List<SimpleEventListenerMetaInfo> metaInfoList = new ArrayList<>();
  
      @Override
      protected void reset(String className) {
          metaInfoList.clear();
      }
  
      @Override
      protected boolean shouldScan(String className) {
          return true;
      }
  
      @Override
      public ByteCodeVisitor byteCodeVisitor() {
          return new _ByteCodeVisitor();
      }
  
      @Override
      public void scanFinished(String className) {
          if (!metaInfoList.isEmpty()) {
              final EventBus eventBus = app().eventBus();
              JobManager jobManager = app().jobManager();
              final ClassInfoRepository repo = app().classLoader().classInfoRepository();
              for (final SimpleEventListenerMetaInfo metaInfo : metaInfoList) {
                  SysEventId hookOn = metaInfo.beforeAppStart() ? SysEventId.DEPENDENCY_INJECTOR_PROVISIONED : SysEventId.PRE_START;
                  jobManager.on(hookOn, "SimpleEventListenerByteCodeScanner:bindEventListener:" + metaInfo.jobId(), new Runnable() {
                      @Override
                      public void run() {
                          ReflectedSimpleEventListener listener = new ReflectedSimpleEventListener(metaInfo.className(), metaInfo.methodName(), metaInfo.paramTypes(), metaInfo.isStatic(), metaInfo.isAsync());
                          /*
                           * Here we might need to build a full class graph so we can generate
                           * permutation of simple event listener method argument types, and bind
                           * it to event in the event bus
                           */
                          if (!app().classLoader().isFullClassGraphBuilt() && $.bool(listener.argumentTypes())) {
                              boolean needBuildFullClassGraph = false;
                              for (Class c : listener.argumentTypes()) {
                                  if ($.isSimpleType(c) || Modifier.isFinal(c.getModifiers())) {
                                      continue;
                                  }
                                  if (null == repo.findNode(c)) {
                                      needBuildFullClassGraph = true;
                                      break;
                                  }
                              }
                              if (needBuildFullClassGraph) {
                                  app().classLoader().buildFullClassGraph();
                              }
                          }
                          for (final Object event : metaInfo.events()) {
                              eventBus.bind(event, listener);
                          }
                      }
                  });
              }
          }
      }
  
      private class _ByteCodeVisitor extends ByteCodeVisitor {
  
          private String className;
  
          @Override
          public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
              className = Type.getObjectType(name).getClassName();
              super.visit(version, access, name, signature, superName, interfaces);
          }
  
          @Override
          public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
              MethodVisitor mv = super.visitMethod(access, name, desc, signature, exceptions);
              final boolean isPublicNotAbstract = AsmTypes.isPublicNotAbstract(access);
              Type[] arguments = Type.getArgumentTypes(desc);
              final List<String> paramTypes = new ArrayList<>();
              for (Type type : arguments) {
                  paramTypes.add(type.getClassName());
              }
              final String methodName = name;
              final boolean isStatic = AsmTypes.isStatic(access);
              return new MethodVisitor(ASM5, mv) {
  
                  private List<Object> events = new ArrayList<>();
                  private List<$.Func0> delayedEvents = new ArrayList<>();
                  private boolean isOnEvent = false;
                  private boolean beforeAppStart = false;
                  private boolean isAsync;
  
                  private String asyncMethodName = null;
  
  
                  @Override
                  public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                      AnnotationVisitor av = super.visitAnnotation(desc, visible);
                      String className = Type.getType(desc).getClassName();
                      final boolean isOn = On.class.getName().equals(className);
                      final boolean isOnC = OnClass.class.getName().equals(className);
                      final boolean isOnE = OnEvent.class.getName().equals(className);
                      if (isOnE) {
                          isOnEvent = true;
                      }
                      boolean isCustomMarker = false;
                      if (!isOn && !isOnC && !isOnE) {
                          Class<?> clz = $.classForName(className);
                          // note we can't use Class.isAnnotationPresent(Class) call here as the class loader might be different
                          // isCustomMarker = clz.isAnnotationPresent(SimpleEventListener.Marker.class);
                          Annotation[] annotations = clz.getAnnotations();
                          for (Annotation annotation : annotations) {
                              if (SimpleEventListener.Marker.class.getCanonicalName().equals(annotation.annotationType().getCanonicalName())) {
                                  isCustomMarker = true;
                                  break;
                              }
                          }
                      }
  
                      if (isOnE || isOn || isOnC || isCustomMarker) {
                          return new AnnotationVisitor(ASM5, av) {
                              @Override
                              public AnnotationVisitor visitArray(String name) {
                                  AnnotationVisitor av0 = super.visitArray(name);
                                  if ("value".equals(name)) {
                                      return new AnnotationVisitor(ASM5, av0) {
                                          @Override
                                          public void visit(String name, Object value) {
                                              if (isOn) {
                                                  events.add(S.string(value).intern());
                                              } else {
                                                  Type type = (Type) value;
                                                  Class<?> c = app().classForName(type.getClassName());
                                                  events.add(c);
                                              }
                                              super.visit(name, value);
                                          }
  
                                          @Override
                                          public void visitEnum(String name, String desc, final String value) {
                                              final String enumClassName = Type.getType(desc).getClassName();
                                              delayedEvents.add(new $.Func0() {
                                                  @Override
                                                  public Object apply() throws NotAppliedException, $.Break {
                                                      Class<? extends Enum> enumClass = app().classForName(enumClassName);
                                                      return (Enum.valueOf(enumClass, value));
                                                  }
                                              });
                                              super.visitEnum(name, desc, value);
                                          }
                                      };
                                  } else {
                                      return av0;
                                  }
                              }
  
                              @Override
                              public void visit(String name, Object value) {
                                  if ("async".equals(name)) {
                                      isAsync = Boolean.parseBoolean(S.string(value));
                                  } else if ("beforeAppStart".equals(name)) {
                                      beforeAppStart = Boolean.parseBoolean(S.string(value));
                                  }
                                  super.visit(name, value);
                              }
  
                              @Override
                              public void visitEnum(String name, String desc, final String value) {
                                  if ("value".equals(name)) {
                                      final String enumClassName = Type.getType(desc).getClassName();
                                      delayedEvents.add(new $.Func0() {
                                          @Override
                                          public Object apply() throws NotAppliedException, $.Break {
                                              Class<? extends Enum> enumClass = app().classForName(enumClassName);
                                              return (Enum.valueOf(enumClass, value));
                                          }
                                      });
                                  }
                                  super.visitEnum(name, desc, value);
                              }
                          };
                      } else if (Async.class.getName().equals(className)) {
                          if (!isPublicNotAbstract) {
                              logger.warn("Error found in method %s.%s: @Async annotation cannot be used with method that are not public or abstract method", className, methodName);
                          } else {
                              asyncMethodName = Async.MethodNameTransformer.transform(methodName);
                          }
                          return av;
                      } else {
                          return av;
                      }
                  }
  
                  @Override
                  public void visitEnd() {
                      if (isOnEvent) {
                          if (paramTypes.isEmpty()) {
                              logger.warn("@OnEvent annotation shall be put on a method with exactly one event object (optionally with other injectable arguments");
                          } else {
                              String type = paramTypes.get(0);
                              events.add(app().classForName(type));
                          }
                      }
                      if (!events.isEmpty() || !delayedEvents.isEmpty()) {
                          SimpleEventListenerMetaInfo metaInfo = new SimpleEventListenerMetaInfo(
                                  events, delayedEvents, className, methodName, asyncMethodName, paramTypes, isAsync, isStatic, beforeAppStart, app());
                          metaInfoList.add(metaInfo);
                      }
                      super.visitEnd();
                  }
              };
          }
      }
  }
  