netwerk/base/ADivertableParentChannel.h

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #ifndef _adivertablechannelparent_h_
   8 #define _adivertablechannelparent_h_
   9
  10 #include "nsISupports.h"
  11
  12 class nsIStreamListener;
  13
  14 namespace mozilla {
  15 namespace net {
  16
  17 // To be implemented by a channel's parent actors, e.g. HttpChannelParent
  18 // and FTPChannelParent. Used by ChannelDiverterParent to divert
  19 // nsIStreamListener callbacks from the child process to a new
  20 // listener in the parent process.
  21 class ADivertableParentChannel : public nsISupports {
  22  public:
  23   // Called by ChannelDiverterParent::DivertTo(nsIStreamListener*).
  24   // The listener should now be used to received nsIStreamListener callbacks,
  25   // i.e. OnStartRequest, OnDataAvailable and OnStopRequest, as if it had been
  26   // passed to AsyncOpen for the channel. A reference to the listener will be
  27   // added and kept until OnStopRequest has completed.
  28   virtual void DivertTo(nsIStreamListener *aListener) = 0;
  29
  30   // Called to suspend parent channel in ChannelDiverterParent constructor.
  31   virtual nsresult SuspendForDiversion() = 0;
  32
  33   // While messages are diverted back from the child to the parent calls to
  34   // suspend/resume the channel must also suspend/resume the message diversion.
  35   // These two functions will be called by nsHttpChannel and nsFtpChannel
  36   // Suspend()/Resume() functions.
  37   virtual nsresult SuspendMessageDiversion() = 0;
  38   virtual nsresult ResumeMessageDiversion() = 0;
  39
  40   // Cancel an ongoing diversion by using IPC to invoke Cancel() in the child.
  41   // This is necessary because most of the channel's state machine is suspended
  42   // during diversion, so an explicit action must be taken to interrupt the
  43   // diversion process so cancellation can be fully processed.
  44   //
  45   // Historically, diversions were assumed to be shortlived, where it was merely
  46   // a question of diverting some small amount of network traffic back to the
  47   // parent.  However, Service Worker child interception made it possible for
  48   // the data to entirely be sourced from the child, which makes diversion
  49   // potentially long-lived.  Especially when large files are involved.
  50   //
  51   // This mechanism is expected to be removed when ServiceWorkers move from
  52   // child intercept to parent intercept (in the short to medium term).
  53   virtual nsresult CancelDiversion() = 0;
  54 };
  55
  56 }  // namespace net
  57 }  // namespace mozilla
  58
  59 #endif