/*
    * Copyright 2016 The Netty Project
    *
    * The Netty Project licenses this file to you 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.
   */
  package io.netty.util.internal;
  
  import io.netty.util.concurrent.Promise;
  import io.netty.util.internal.logging.InternalLogger;
  
  /**
   * Internal utilities to notify {@link Promise}s.
   */
  public final class PromiseNotificationUtil {
  
      private PromiseNotificationUtil() { }
  
      /**
       * Try to cancel the {@link Promise} and log if {@code logger} is not {@code null} in case this fails.
       */
      public static void tryCancel(Promise<?> p, InternalLogger logger) {
          if (!p.cancel(false) && logger != null) {
              Throwable err = p.cause();
              if (err == null) {
                  logger.warn("Failed to cancel promise because it has succeeded already: {}", p);
              } else {
                  logger.warn(
                          "Failed to cancel promise because it has failed already: {}, unnotified cause:",
                          p, err);
              }
          }
      }
  
      /**
       * Try to mark the {@link Promise} as success and log if {@code logger} is not {@code null} in case this fails.
       */
      public static <V> void trySuccess(Promise<? super V> p, V result, InternalLogger logger) {
          if (!p.trySuccess(result) && logger != null) {
              Throwable err = p.cause();
              if (err == null) {
                  logger.warn("Failed to mark a promise as success because it has succeeded already: {}", p);
              } else {
                  logger.warn(
                          "Failed to mark a promise as success because it has failed already: {}, unnotified cause:",
                          p, err);
              }
          }
      }
  
      /**
       * Try to mark the {@link Promise} as failure and log if {@code logger} is not {@code null} in case this fails.
       */
      public static void tryFailure(Promise<?> p, Throwable cause, InternalLogger logger) {
          if (!p.tryFailure(cause) && logger != null) {
              Throwable err = p.cause();
              if (err == null) {
                  logger.warn("Failed to mark a promise as failure because it has succeeded already: {}", p, cause);
              } else {
                  logger.warn(
                          "Failed to mark a promise as failure because it has failed already: {}, unnotified cause: {}",
                          p, ThrowableUtil.stackTraceToString(err), cause);
              }
          }
      }
  
  }