#pragma once

#include "envoy/http/async_client.h"

namespace Envoy {

namespace Http {

/**

 * Keeps track of active async HTTP requests to be able to cancel them on destruction.

 */

class AsyncClientRequestTracker {

public:

  /**

   * Cancels all known active async HTTP requests.

   */

  ~AsyncClientRequestTracker();

  /**

   * Includes a given async HTTP request into a set of known active requests.

   * @param request request handle

   */

  void add(AsyncClient::Request& request);

  /**

   * Excludes a given async HTTP request from a set of known active requests.

   *

   * NOTE: Asymmetry between signatures of add() and remove() is caused by the difference

   *       between contexts in which these methods will be used.

   *       add() will be called right after AsyncClient::send() when request.cancel() is

   *       perfectly valid and desirable.

   *       However, remove() will be called in the context of

   *       AsyncClient::Callbacks::[onSuccess | onFailure] where request.cancel() is no longer

   *       expected and therefore get prevented by means of "const" modifier.

   *

   * @param request request handle

   */

  void remove(const AsyncClient::Request& request);

private:

  // Track active async HTTP requests to be able to cancel them on destruction.

  absl::flat_hash_set<AsyncClient::Request*> active_requests_;

};

} // namespace Http

} // namespace Envoy