text: /*
   * Copyright 2017 Google
   *
   * 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.
   */
  
  #import <Foundation/Foundation.h>
  
  NS_ASSUME_NONNULL_BEGIN
  
  /** @typedef FIRAuthSerialTaskCompletionBlock
      @brief The type of method a @c FIRAuthSerialTask must call when it is complete.
   */
  typedef void (^FIRAuthSerialTaskCompletionBlock)(void);
  
  /** @typedef FIRAuthSerialTask
      @brief Represents a unit of work submitted to a task queue.
      @param complete The task MUST call the complete method when done.
   */
  typedef void (^FIRAuthSerialTask)(FIRAuthSerialTaskCompletionBlock complete);
  
  /** @class FIRAuthSerialTaskQueue
      @brief An easy to use serial task queue which supports a callback-based completion notification
          system for easy asyncronous call chaining.
   */
  @interface FIRAuthSerialTaskQueue : NSObject
  
  /** @fn enqueueTask:
      @brief Enqueues a task for serial execution in the queue.
      @remarks The task MUST call the complete method when done. This method is thread-safe.
          The task block won't be executed concurrently with any other blocks in other task queues or
          the global work queue as returned by @c FIRAuthGlobalWorkQueue , but an uncompleted task
          (e.g. task block finished executation before complete method is called at a later time)
          does not affect other task queues or the global work queue.
   */
  - (void)enqueueTask:(FIRAuthSerialTask)task;
  
  @end
  
  NS_ASSUME_NONNULL_END
  