text: /* Copyright 2015 greenbytes GmbH (https://www.greenbytes.de)
   *
   * 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.
   */
  
  #include <assert.h>
  #include <stddef.h>
  
  #include <httpd.h>
  #include <http_core.h>
  
  #include "h2_task.h"
  #include "h2_task_queue.h"
  
  
  h2_task_queue *h2_tq_create(long id, apr_pool_t *pool)
  {
      h2_task_queue *q = apr_pcalloc(pool, sizeof(h2_task_queue));
      if (q) {
          q->id = id;
          APR_RING_ELEM_INIT(q, link);
          APR_RING_INIT(&q->tasks, h2_task, link);
      }
      return q;
  }
  
  void h2_tq_destroy(h2_task_queue *q)
  {
      while (!H2_TASK_LIST_EMPTY(&q->tasks)) {
          h2_task *task = H2_TASK_LIST_FIRST(&q->tasks);
          H2_TASK_REMOVE(task);
      }
  }
  
  static int in_list(h2_task_queue *q, h2_task *task)
  {
      h2_task *e;
      for (e = H2_TASK_LIST_FIRST(&q->tasks); 
           e != H2_TASK_LIST_SENTINEL(&q->tasks);
           e = H2_TASK_NEXT(e)) {
          if (e == task) {
              return 1;
          }
      }
      return 0;
  }
  
  int h2_tq_empty(h2_task_queue *q)
  {
      return H2_TASK_LIST_EMPTY(&q->tasks);
  }
  
  void h2_tq_append(h2_task_queue *q, struct h2_task *task)
  {
      H2_TASK_LIST_INSERT_TAIL(&q->tasks, task);
  }
  
  apr_status_t h2_tq_remove(h2_task_queue *q, struct h2_task *task)
  {
      if (in_list(q, task)) {
          H2_TASK_REMOVE(task);
          return APR_SUCCESS;
      }
      return APR_NOTFOUND;
  }
  
  h2_task *h2_tq_pop_first(h2_task_queue *q)
  {
      if (!H2_TASK_LIST_EMPTY(&q->tasks)) {
          h2_task *task = H2_TASK_LIST_FIRST(&q->tasks);
          H2_TASK_REMOVE(task);
          return task;
      }
      return NULL;
  }
  
  
  
  