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.app.*;
  import act.asm.AsmContext;
  import act.cli.CliContext;
  import act.handler.DelegateRequestHandler;
  import act.handler.RequestHandler;
  import act.handler.builtin.controller.ControllerAction;
  import act.handler.builtin.controller.RequestHandlerProxy;
  import act.handler.builtin.controller.impl.ReflectedHandlerInvoker;
  import act.i18n.I18n;
  import org.osgl.$;
  import org.osgl.http.H;
  import org.osgl.mvc.MvcConfig;
  import org.osgl.util.E;
  import org.osgl.util.S;
  
  import java.lang.annotation.ElementType;
  import java.lang.reflect.Method;
  import java.util.ArrayList;
  import java.util.List;
  
  public interface ActError {
      Throwable getCauseOrThis();
      Throwable getCause();
      SourceInfo sourceInfo();
      List<String> stackTrace();
      String getMessage();
      String getLocalizedMessage();
      boolean isErrorSpot(String traceLine, String nextTraceLine);
  
      class Util {
  
          public static String errorMessage(H.Status status) {
              return errorMessage(status, null);
          }
  
          public static String errorMessage(H.Status status, String message, Object ... args) {
              if (S.notBlank(message)) {
                  return S.fmt(message, args);
              }
              if (Act.isProd()) {
                  return MvcConfig.errorMessage(status);
              }
              ActionContext ctx = ActionContext.current();
              if (null == ctx) {
                  return MvcConfig.errorMessage(status);
              }
              RequestHandler handler = ctx.handler();
              if (null == handler) {
                  return MvcConfig.errorMessage(status);
              }
              if (H.Status.NOT_FOUND == status) {
                  return I18n.i18n(Act.class, "e404.null_value_returned", handler);
              }
              return I18n.i18n(Act.class, "error.on_invoking", MvcConfig.errorMessage(status), handler);
          }
  
          public static SourceInfo loadSourceInfo(Throwable cause, Class<? extends ActError> errorClass) {
              if (cause instanceof SourceInfo) {
                  return (SourceInfo) cause;
              }
              try {
                  return _loadSourceInfo(cause.getStackTrace(), errorClass);
              } catch (RuntimeException e) {
                  Act.LOGGER.warn(e, "Error loading source info");
                  return null;
              }
          }
  
          private static SourceInfo _loadSourceInfo(StackTraceElement[] sa, Class<? extends ActError> errorClass) {
              SourceInfo info = loadSourceInfo(sa, errorClass);
              if (null != info) {
                  return info;
              }
              int len = sa.length;
              StackTraceElement[] caller = sa;
              if (len > 0) {
                  caller = new StackTraceElement[len - 1];
                  System.arraycopy(sa, 1, caller, 0, len - 1);
              }
  
              ActContext ctx = ActContext.Base.currentContext();
              if (null == ctx) {
                  return loadSourceInfo(caller, errorClass);
              }
              if (ctx instanceof ActionContext) {
                  ActionContext actionContext = $.cast(ctx);
                  RequestHandler handler = actionContext.handler();
                  String actionName = handler.toString();
                  for (StackTraceElement element : caller) {
                      if (actionName.contains(element.getMethodName()) && actionName.contains(element.getClassName())) {
                          return loadSourceInfo(caller, errorClass);
                      }
                  }
                  if (handler instanceof DelegateRequestHandler) {
                      handler = ((DelegateRequestHandler) handler).realHandler();
                  }
                  if (handler instanceof RequestHandlerProxy) {
                      RequestHandlerProxy proxy = $.cast(handler);
                      try {
                          ControllerAction action = proxy.actionHandler();
                          ReflectedHandlerInvoker invoker = $.cast(action.invoker());
                          return loadSourceInfo(invoker.method());
                      } catch (RuntimeException e) {
                          // refer: https://github.com/actframework/actframework/issues/1264
                          // try my best to get the method
                          String methodName = S.cut(actionName).afterLast(".");
                          String className = S.cut(actionName).beforeLast(".");
                          Class<?> clz = Act.classForName(className);
                          for (Method m : clz.getMethods()) {
                              if (methodName.equals(m.getName())) {
                                  return loadSourceInfo(m);
                              }
                          }
                          for (Method m : clz.getDeclaredMethods()) {
                              if (methodName.equals(m.getName())) {
                                  return loadSourceInfo(m);
                              }
                          }
                      }
                  }
                  return loadSourceInfo(caller, errorClass);
              } else if (ctx instanceof CliContext) {
                  CliContext cliContext = $.cast(ctx);
                  Method method = cliContext.handlerMethod();
                  for (StackTraceElement element : caller) {
                      if (method.getName().equals(element.getMethodName()) && method.getDeclaringClass().getName().equals(element.getClassName())) {
                          return loadSourceInfo(caller, errorClass);
                      }
                  }
                  return loadSourceInfo(method);
              }
              return loadSourceInfo(caller, errorClass);
          }
  
          public static SourceInfo loadSourceInfo(Class<? extends ActError> errorClass) {
              return loadSourceInfo(new RuntimeException(), errorClass);
          }
  
          public static List<String> stackTraceOf(ActError error) {
              Throwable cause = error.getCause();
              ActError root = error;
              if (null == cause) {
                  cause = (Throwable) error;
                  root = null;
              }
              return stackTraceOf(cause, root);
          }
  
          public static List<String> stackTraceOf(Throwable t, ActError root) {
              List<String> l = new ArrayList<>();
              while (null != t) {
                  StackTraceElement[] a = t.getStackTrace();
                  for (StackTraceElement e : a) {
                      String line = S.concat("at ", e.toString());
                      if (line.contains("org.osgl.util.E.")) {
                          // skip E util class
                          continue;
                      }
                      if (l.contains(line)) {
                          l.add(line);
                          // caused by stack trace stop at here
                          break;
                      }
                      l.add(line);
                  }
                  t = t.getCause();
                  if (t == root) {
                      break;
                  }
                  if (null != t) {
                      l.add("Caused by " + t.toString());
                  }
              }
              return l;
          }
  
          public static SourceInfo loadSourceInfo(StackTraceElement[] stackTraceElements, Class<? extends ActError> errClz) {
              E.illegalStateIf(Act.isProd());
              DevModeClassLoader cl = (DevModeClassLoader) App.instance().classLoader();
              String errClzName = errClz.getName();
              for (StackTraceElement stackTraceElement : stackTraceElements) {
                  int line = stackTraceElement.getLineNumber();
                  if (line <= 0) {
                      continue;
                  }
                  String className = stackTraceElement.getClassName();
                  if (S.eq(className, errClzName)) {
                      continue;
                  }
                  Source source = cl.source(className);
                  if (null == source) {
                      continue;
                  }
                  return new SourceInfoImpl(source, line);
              }
              return null;
          }
  
          public static SourceInfo loadSourceInfo(Method method) {
              return loadSourceInfo(method.getDeclaringClass().getName(), method.getName(), true, null);
          }
  
          public static SourceInfo loadSourceInfo(AsmContext asmContext) {
              return loadSourceInfo(asmContext.className(), asmContext.name(), ElementType.METHOD == asmContext.type(), asmContext.lineNo());
          }
  
          private static SourceInfo loadSourceInfo(String className, String elementName, boolean isMethod, Integer lineNo) {
              E.illegalStateIf(Act.isProd());
              DevModeClassLoader cl = (DevModeClassLoader) App.instance().classLoader();
              Source source = cl.source(className);
              if (null == source) {
                  return null;
              }
              List<String> lines = source.lines();
              Line candidate = null;
              String pattern = isMethod ?
                      S.concat("^\\s*.*", elementName, "\\s*\\(.*") :
                      S.concat("^\\s*.*", elementName, "[^\\(\\{]*");
              if (null != lineNo) {
                  return new SourceInfoImpl(source, lineNo);
              }
              for (int i = 0; i < lines.size(); ++i) {
                  String line = lines.get(i);
                  if (line.matches(pattern)) {
                      candidate = new Line(line, i + 1);
                      if (candidate.forSure) {
                          return new SourceInfoImpl(source, candidate.no);
                      }
                  }
              }
              if (null != candidate) {
                  return new SourceInfoImpl(source, candidate.no);
              }
              return new SourceInfoImpl(source, 1);
          }
  
          private static class Line {
              String line;
              int no;
              boolean forSure;
              Line(String line, int no) {
                  this.line = line;
                  this.no = no;
                  forSure = line.contains("public ");
              }
          }
      }
  }
  