content: package act.util;
  
  /*-
   * #%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.Destroyable;
  import act.annotations.Alias;
  import act.app.App;
  import act.app.AppByteCodeScannerBase;
  import act.app.AppClassLoader;
  import act.app.event.SysEventId;
  import act.asm.*;
  import act.internal.password.PasswordMetaInfo;
  import act.meta.ClassMetaInfoManager;
  import org.osgl.$;
  import org.osgl.util.C;
  import org.osgl.util.E;
  import org.osgl.util.S;
  
  import java.lang.reflect.Modifier;
  import java.util.*;
  import javax.enterprise.context.ApplicationScoped;
  import javax.inject.Inject;
  
  /**
   * ActFramework will do the following byte code enhancement to classes that are
   * instance of `SimpleBean:
   * <p>
   * 1. Create default constructor if not provided (usually for ORM library usage)
   * 2. Create getter/setter for public non-static fields
   * 3. Convert all public fields access into getter/setter calls
   */
  public interface SimpleBean {
  
      /**
       * Keep track of the class info needed by simple bean enhancement logic
       */
      @ApplicationScoped
      class MetaInfo extends DestroyableBase {
          // the class name
          private String className;
          // keep public non-static fields
          private Map<String, $.T2<String, String>> publicFields;
          // keep track @Sensitive fields
          private Set<String> sensitiveFields;
          private Set<String> passwordFields;
          private Map<String, String> fieldAliases;
          private Map<String, String> fieldLabels;
  
          @Inject
          MetaInfo(String className, Map<String, $.T2<String, String>> publicFields, Map<String, String> aliases, Map<String, String> labels) {
              this.className = className;
              this.publicFields = publicFields;
              this.sensitiveFields = new HashSet<>();
              this.passwordFields = new HashSet<>();
              this.fieldAliases = aliases;
              this.fieldLabels = labels;
          }
  
          public String getClassName() {
              return className;
          }
  
          public void setClassName(String className) {
              this.className = className;
          }
  
          public Map<String, $.T2<String, String>> getPublicFields() {
              return C.Map(publicFields);
          }
  
          public void addSensitiveField(String fieldName) {
              E.illegalArgumentIf(passwordFields.contains(fieldName), "@Sensitive and @Password cannot be used together");
              sensitiveFields.add(fieldName);
          }
  
          public void addPasswordField(String fieldName) {
              E.illegalArgumentIf(sensitiveFields.contains(fieldName), "@Sensitive and @Password cannot be used together");
              passwordFields.add(fieldName);
          }
  
          public boolean isSensitive(String fieldName) {
              return sensitiveFields.contains(fieldName);
          }
  
          public String aliasOf(String fieldName) {
              String s = fieldAliases.get(fieldName);
              return null == s ? fieldName : s;
          }
  
          public String labelOf(String fieldName) {
              String s = fieldLabels.get(fieldName);
              return null == s ? fieldName : s;
          }
  
          public boolean isPassword(String fieldName) {
              return passwordFields.contains(fieldName);
          }
  
          public boolean hasPublicField() {
              return !publicFields.isEmpty();
          }
  
          @Override
          protected void releaseResources() {
              publicFields.clear();
          }
  
          static boolean isBoolean(String desc) {
              return "Z".equals(desc) || "java/lang/Boolean".equals(desc);
          }
      }
  
      @ApplicationScoped
      class MetaInfoManager extends LogSupportedDestroyableBase {
          private static final String INTF_SIMPLE_BEAN = SimpleBean.class.getName();
          private ClassInfoRepository classInfoRepository;
          private Map<String, MetaInfo> registry = new HashMap<>();
  
          @Inject
          public MetaInfoManager(AppClassLoader classLoader) {
              classInfoRepository = classLoader.classInfoRepository();
          }
  
          @Override
          protected void releaseResources() {
              Destroyable.Util.tryDestroyAll(registry.values(), ApplicationScoped.class);
              registry.clear();
          }
  
          public void register(MetaInfo metaInfo) {
              registry.put(metaInfo.getClassName(), metaInfo);
          }
  
          public boolean isPublicField(String className, String field) {
              MetaInfo metaInfo = get(className);
              return null != metaInfo && metaInfo.publicFields.containsKey(field) && isSimpleBean(className);
          }
  
          private boolean isSimpleBean(String className) {
              ClassNode node = classInfoRepository.node(className);
              if (null == node) {
                  return false;
              }
              return !node.isInterface() && node.hasInterface(INTF_SIMPLE_BEAN);
          }
  
          public MetaInfo get(String className) {
              return registry.get(className);
          }
  
          public $.Option<MetaInfo> safeGet(String className) {
              return $.some(get(className));
          }
      }
  
      class ByteCodeScanner extends AppByteCodeScannerBase {
  
          @Override
          protected boolean shouldScan(String className) {
              return true;
          }
  
          @Override
          public ByteCodeVisitor byteCodeVisitor() {
              return new SimpleBeanByteCodeVisitor();
          }
  
          @Override
          public void scanFinished(String className) {
  
          }
  
          private static class SimpleBeanByteCodeVisitor extends ByteCodeVisitor {
  
              private static final String RECORD = "java/lang/Record";
              private static final String SIMPLE_BEAN = "act/util/SimpleBean";
  
              private static final String ALIAS_DESC = Type.getType(Alias.class).getDescriptor();
              private static final String LABEL_DESC = Type.getType(Label.class).getDescriptor();
              private String className;
              private boolean isPublicClass;
              // key: (desc, signature)
              private Map<String, $.T2<String, String>> publicFields = new LinkedHashMap<>();
              private Map<String, String> aliases = new LinkedHashMap<>();
              private Map<String, String> labels = new LinkedHashMap<>();
              private boolean isRecord;
  
              @Override
              public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
                  if (isPublic(access)) {
                      isPublicClass = true;
                      className = Type.getObjectType(name).getClassName();
                      isRecord = RECORD.equals(superName);
                      if (isRecord) {
                          interfaces = new String[] {SIMPLE_BEAN};
                      }
                  }
                  super.visit(version, access, name, signature, superName, interfaces);
              }
  
              @Override
              public FieldVisitor visitField(int access, final String name, String desc, String signature, Object value) {
                  if (isRecord) access = Modifier.PUBLIC;
                  FieldVisitor fv = super.visitField(access, name, desc, signature, value);
                  if (isPublicClass && AsmTypes.isPublic(access) && !AsmTypes.isStatic(access)) {
                      publicFields.put(name, $.T2(desc, signature));
                      return new FieldVisitor(ASM5, fv) {
                          private String alias;
                          private String label;
                          @Override
                          public AnnotationVisitor visitAnnotation(String desc, boolean visible) {
                              AnnotationVisitor av = super.visitAnnotation(desc, visible);
                              if (ALIAS_DESC.equals(desc)) {
                                  return new AnnotationVisitor(ASM5, av) {
                                      @Override
                                      public void visit(String name, Object value) {
                                          alias = S.string(value);
                                      }
                                  };
                              } else if (LABEL_DESC.equals(desc)) {
                                  return new AnnotationVisitor(ASM5, av) {
                                      @Override
                                      public void visit(String name, Object value) {
                                          label = S.string(value);
                                      }
                                  };
                              }
                              return av;
                          }
  
                          @Override
                          public void visitEnd() {
                              if (null != alias && S.neq(name, alias)) {
                                  aliases.put(name, alias);
                                  aliases.put(alias, name);
                              }
                              if (null != label && S.neq(name, label)) {
                                  labels.put(name, label);
                                  labels.put(label, name);
                              }
                              super.visitEnd();
                          }
                      };
                  }
                  return fv;
              }
  
              @Override
              public void visitEnd() {
                  if (isPublicClass) {
                      Act.app().jobManager().on(SysEventId.APP_CODE_SCANNED, "SimpleBeanByteCodeVisitor:registerToMetaInfoManager:" + className, new Runnable() {
                          @Override
                          public void run() {
                              SimpleBean.MetaInfoManager metaInfoManager = Act.app().classLoader().simpleBeanInfoManager();
                              if (metaInfoManager.isSimpleBean(className)) {
                                  MetaInfo metaInfo = new MetaInfo(className, publicFields, aliases, labels);
                                  metaInfoManager.register(metaInfo);
                              }
                          }
                      });
                  }
                  super.visitEnd();
              }
          }
      }
  
      class ByteCodeEnhancer extends AppByteCodeEnhancer<ByteCodeEnhancer> {
  
          public static final int PRIORITY = 9;
  
          private MetaInfoManager metaInfoManager;
          private ClassInfoRepository classInfoRepository;
          private boolean isSimpleBean = false;
          private boolean hasPublicFields = false;
          private Set<String> aliases = new HashSet<>();
          private Map<String, $.T2<String, String>> getters = new LinkedHashMap<>();
          private Map<String, $.T2<String, String>> setters = new LinkedHashMap<>();
          private boolean needDefaultConstructor = false;
          private String classDesc;
          private String superClassDesc;
          private MetaInfo metaInfo;
          private ClassMetaInfoManager<PasswordMetaInfo> passwordMetaInfoManager;
          private PasswordMetaInfo passwordMetaInfo;
  
          public ByteCodeEnhancer() {
          }
  
          public ByteCodeEnhancer(ClassVisitor cv) {
              super(S.F.startsWith("act.").negate(), cv);
          }
  
  
          @Override
          protected Class<ByteCodeEnhancer> subClass() {
              return ByteCodeEnhancer.class;
          }
  
          @Override
          public int priority() {
              return PRIORITY;
          }
  
          @Override
          protected void reset() {
              this.isSimpleBean = false;
              this.hasPublicFields = false;
              this.aliases.clear();
              this.getters.clear();
              this.setters.clear();
              this.needDefaultConstructor = false;
              this.classDesc = null;
              this.superClassDesc = null;
              this.metaInfo = null;
              super.reset();
          }
  
          @Override
          public AppByteCodeEnhancer app(App app) {
              AppClassLoader classLoader = app.classLoader();
              classInfoRepository = classLoader.classInfoRepository();
              metaInfoManager = classLoader.simpleBeanInfoManager();
              passwordMetaInfoManager = app.classMetaInfoManager(PasswordMetaInfo.class);
              return super.app(app);
          }
  
          @Override
          public void visit(int version, int access, String name, String signature, String superName, String[] interfaces) {
              classDesc = name;
              String className = Type.getObjectType(name).getClassName();
              passwordMetaInfo = passwordMetaInfoManager.get(className);
              isSimpleBean = metaInfoManager.isSimpleBean(className);
              if (isSimpleBean) {
                  needDefaultConstructor = true;
                  MetaInfo metaInfo = metaInfoManager.get(className);
                  superClassDesc = superName;
                  if (null != metaInfo) {
                      this.metaInfo = metaInfo;
                      Map<String, $.T2<String, String>> publicFields = metaInfo.publicFields;
                      if (!publicFields.isEmpty()) {
                          getters.putAll(publicFields);
                          setters.putAll(publicFields);
                          hasPublicFields = true;
                      } else {
                          hasPublicFields = false;
                      }
                  }
              }
              super.visit(version, access, name, signature, superName, interfaces);
          }
  
          @Override
          public MethodVisitor visitMethod(int access, String name, String desc, String signature, String[] exceptions) {
              MethodVisitor mv = new PropertyAssignMethodVisitor(super.visitMethod(access, name, desc, signature, exceptions), name);
              if (!isSimpleBean) {
                  return mv;
              }
  
              if ("<init>".equals(name) && "()V".equals(desc)) {
                  needDefaultConstructor = false;
              }
  
              if (!hasPublicFields) {
                  return mv;
              }
              /*
               * Check if there are getter or setter function already defined for a field
               * Note we don't check the signature and access here intentionally
               */
              String getter = fieldNameFromGetterSetter(name, true);
              if (null != getter) {
                  // found getter for the field
                  getters.remove(getter);
                  //getters.remove(metaInfo.aliasOf(getter));
              }
              String setter = fieldNameFromGetterSetter(name, false);
              if (null != setter) {
                  // found setter for the field
                  setters.remove(setter);
                  ///setters.remove(metaInfo.aliasOf(setter));
              }
              return mv;
          }
  
          private String fieldNameFromGetterSetter(String methodName, boolean getter) {
              if (methodName.startsWith(getter ? "get" : "set")) {
                  String fieldName = methodName.substring(3);
                  if (!fieldName.isEmpty()) {
                      char c = fieldName.charAt(0);
                      if (Character.isUpperCase(c)) {
                          return ("" + fieldName.charAt(0)).toLowerCase() + fieldName.substring(1);
                      }
                  }
              }
              return getter ? fieldNameFromBooleanGetter(methodName) : null;
          }
  
          private String fieldNameFromGetterSetter(String methodName) {
              if (methodName.startsWith("get") || methodName.startsWith("set")) {
                  String fieldName = methodName.substring(3);
                  if (!fieldName.isEmpty()) {
                      char c = fieldName.charAt(0);
                      if (Character.isUpperCase(c)) {
                          return ("" + fieldName.charAt(0)).toLowerCase() + fieldName.substring(1);
                      }
                  }
              }
              return fieldNameFromBooleanGetter(methodName);
          }
  
          private String fieldNameFromBooleanGetter(String methodName) {
              if (methodName.startsWith("is")) {
                  String fieldName = methodName.substring(2);
                  if (!fieldName.isEmpty()) {
                      char c = fieldName.charAt(0);
                      if (Character.isUpperCase(c)) {
                          return ("" + fieldName.charAt(0)).toLowerCase() + fieldName.substring(1);
                      }
                  }
              }
              return null;
          }
  
          @Override
          public void visitEnd() {
              if (needDefaultConstructor) {
                  addDefaultConstructor();
              }
              if (!getters.isEmpty()) {
                  addGetters();
              }
              if (!setters.isEmpty()) {
                  addSetters();
              }
              super.visitEnd();
          }
  
          private void addDefaultConstructor() {
              MethodVisitor mv = visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
              mv.visitCode();
              mv.visitVarInsn(ALOAD, 0);
              mv.visitMethodInsn(INVOKESPECIAL, superClassDesc, "<init>", "()V", false);
              mv.visitInsn(RETURN);
              mv.visitMaxs(1, 1);
              mv.visitEnd();
          }
  
          private void addGetters() {
              for (Map.Entry<String, $.T2<String, String>> field : C.list(getters.entrySet())) {
                  addGetter(field);
              }
          }
  
          private void addSetters() {
              for (Map.Entry<String, $.T2<String, String>> field : C.list(setters.entrySet())) {
                  addSetter(field);
              }
          }
  
          private void addGetter(Map.Entry<String, $.T2<String, String>> field) {
              String name = field.getKey();
              if (metaInfo.isSensitive(name)) {
                  return;
              }
              String desc = field.getValue()._1;
              String signature = field.getValue()._2;
              if (null != signature) {
                  signature = S.concat("()", signature);
              }
  
              MethodVisitor mv = visitMethod(ACC_PUBLIC, getterName(name, MetaInfo.isBoolean(desc)), S.concat("()", desc), signature, null);
              mv.visitCode();
              mv.visitVarInsn(ALOAD, 0);
              mv.visitFieldInsn(GETFIELD, classDesc, name, desc);
              mv.visitInsn(returnCode(desc));
              if (_D == desc.hashCode() || _J == desc.hashCode()) {
                  mv.visitMaxs(2, 1);
              } else {
                  mv.visitMaxs(1, 1);
              }
              mv.visitEnd();
          }
  
          private void addSetter(Map.Entry<String, $.T2<String, String>> field) {
              String name = field.getKey();
              if (metaInfo.isSensitive(name) || null != passwordMetaInfo && passwordMetaInfo.isPasswordField(name)) {
                  return;
              }
              String desc = field.getValue()._1;
              String signature = field.getValue()._2;
  
              if (null != signature) {
                  signature = S.concat("(", signature, ")V");
              }
              MethodVisitor mv = visitMethod(ACC_PUBLIC, setterName(name), S.concat("(", desc, ")V"), signature, null);
              mv.visitCode();
              mv.visitVarInsn(ALOAD, 0);
              mv.visitVarInsn(loadCode(desc), 1);
              mv.visitFieldInsn(PUTFIELD, classDesc, name, desc);
              mv.visitInsn(RETURN);
              if (_D == desc.hashCode() || _J == desc.hashCode()) {
                  mv.visitMaxs(3, 3);
              } else {
                  mv.visitMaxs(2, 2);
              }
              mv.visitEnd();
          }
  
          private String getterName(String fieldName, boolean isBoolean) {
              return (isBoolean ? "is" : "get") + S.capFirst(fieldName);
          }
  
          private String setterName(String fieldName) {
              return "set" + S.capFirst(fieldName);
          }
  
          private static final int _I = 'I';
          private static final int _Z = 'Z';
          private static final int _S = 'S';
          private static final int _B = 'B';
          private static final int _C = 'C';
  
          private static final int _D = 'D';
          private static final int _J = 'J';
          private static final int _F = 'F';
  
  
          private int loadCode(String desc) {
              return loadOrReturnCode(desc, true);
          }
  
          private int returnCode(String desc) {
              return loadOrReturnCode(desc, false);
          }
  
          private int loadOrReturnCode(String desc, boolean load) {
              switch (desc.hashCode()) {
                  case _I:
                  case _Z:
                  case _S:
                  case _B:
                  case _C:
                      return load ? ILOAD : IRETURN;
                  case _J:
                      return load ? LLOAD : LRETURN;
                  case _D:
                      return load ? DLOAD : DRETURN;
                  case _F:
                      return load ? FLOAD : FRETURN;
                  default:
                      return load ? ALOAD : ARETURN;
              }
          }
  
          private class PropertyAssignMethodVisitor extends MethodVisitor {
              private String fieldName;
  
              public PropertyAssignMethodVisitor(MethodVisitor upstream, String name) {
                  super(ASM5, upstream);
                  this.fieldName = fieldNameFromGetterSetter(name);
              }
  
              @Override
              public void visitFieldInsn(int opcode, String owner, String name, String desc) {
                  if (shouldReplaceWithGetterOrSetter(owner, name)) {
                      switch (opcode) {
                          case PUTFIELD:
                              visitMethodInsn(INVOKEVIRTUAL, owner, setterName(name), "(" + desc + ")V");
                              break;
                          case GETFIELD:
                              visitMethodInsn(INVOKEVIRTUAL, owner, getterName(name, MetaInfo.isBoolean(desc)), "()" + desc);
                              break;
                          default:
                              throw new IllegalStateException("visitFieldInsn opcode not supported: " + opcode);
                      }
                  } else {
                      super.visitFieldInsn(opcode, owner, name, desc);
                  }
              }
  
              private boolean shouldReplaceWithGetterOrSetter(String owner, String name) {
                  ClassNode node = classInfoRepository.node(owner);
                  if (null == node || !node.hasInterface(SimpleBean.class.getName())) {
                      return false;
                  }
                  String ownerClass = Type.getObjectType(owner).getClassName();
                  MetaInfo metaInfo = metaInfoManager.get(ownerClass);
                  while (true) {
                      if (null != metaInfo && metaInfo.publicFields.containsKey(name)) {
                          return !insideGetterSetter(owner, name, metaInfo.aliasOf(name));
                      }
                      node = node.parent();
                      if (null == node) {
                          return false;
                      }
                      metaInfo = metaInfoManager.get(node.name());
                  }
              }
  
              private boolean insideGetterSetter(String owner, String name, String alias) {
                  return !(null == fieldName || S.neq(classDesc, owner) || (S.neq(fieldName, name) && S.neq(fieldName, alias)));
              }
          }
      }
  
  }
  