/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#ifndef _adivertablechannelparent_h_
#define _adivertablechannelparent_h_

#include "nsISupports.h"

class nsIStreamListener;

namespace mozilla {
namespace net {

// To be implemented by a channel's parent actors, e.g. HttpChannelParent
// and FTPChannelParent. Used by ChannelDiverterParent to divert
// nsIStreamListener callbacks from the child process to a new
// listener in the parent process.
class ADivertableParentChannel : public nsISupports {
 public:
  // Called by ChannelDiverterParent::DivertTo(nsIStreamListener*).
  // The listener should now be used to received nsIStreamListener callbacks,
  // i.e. OnStartRequest, OnDataAvailable and OnStopRequest, as if it had been
  // passed to AsyncOpen for the channel. A reference to the listener will be
  // added and kept until OnStopRequest has completed.
  virtual void DivertTo(nsIStreamListener* aListener) = 0;

  // Called to suspend parent channel in ChannelDiverterParent constructor.
  virtual nsresult SuspendForDiversion() = 0;

  // While messages are diverted back from the child to the parent calls to
  // suspend/resume the channel must also suspend/resume the message diversion.
  // These two functions will be called by nsHttpChannel and nsFtpChannel
  // Suspend()/Resume() functions.
  virtual nsresult SuspendMessageDiversion() = 0;
  virtual nsresult ResumeMessageDiversion() = 0;

  // Cancel an ongoing diversion by using IPC to invoke Cancel() in the child.
  // This is necessary because most of the channel's state machine is suspended
  // during diversion, so an explicit action must be taken to interrupt the
  // diversion process so cancellation can be fully processed.
  //
  // Historically, diversions were assumed to be shortlived, where it was merely
  // a question of diverting some small amount of network traffic back to the
  // parent.  However, Service Worker child interception made it possible for
  // the data to entirely be sourced from the child, which makes diversion
  // potentially long-lived.  Especially when large files are involved.
  //
  // This mechanism is expected to be removed when ServiceWorkers move from
  // child intercept to parent intercept (in the short to medium term).
  virtual nsresult CancelDiversion() = 0;
};

}  // namespace net
}  // namespace mozilla

#endif