netwerk/protocol/ftp/FTPChannelParent.cpp
author Jonathan Kingston <jkt@mozilla.com>
Wed, 27 Feb 2019 23:41:04 +0000
changeset 461558 b5f7ff4ca9b58d002c2bebe0a11b529680068b0c
parent 460956 7bffd747d54adf39be339cfac01d785e4654ea55
child 461559 c48f47f793c0f0d9b4acf2caf9324b8bd7a5a683
permissions -rw-r--r--
Bug 1525319 - Removing context from OnStartRequest r=valentin Differential Revision: https://phabricator.services.mozilla.com/D20769

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set sw=2 ts=8 et 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/. */

#include "mozilla/net/FTPChannelParent.h"
#include "nsStringStream.h"
#include "mozilla/net/ChannelEventQueue.h"
#include "mozilla/dom/TabParent.h"
#include "nsFTPChannel.h"
#include "nsNetCID.h"
#include "nsNetUtil.h"
#include "nsQueryObject.h"
#include "nsFtpProtocolHandler.h"
#include "nsIAuthPrompt.h"
#include "nsIAuthPromptProvider.h"
#include "nsIEncodedChannel.h"
#include "nsIHttpChannelInternal.h"
#include "nsISecureBrowserUI.h"
#include "nsIForcePendingChannel.h"
#include "mozilla/ipc/IPCStreamUtils.h"
#include "mozilla/ipc/URIUtils.h"
#include "mozilla/Unused.h"
#include "SerializedLoadContext.h"
#include "nsIContentPolicy.h"
#include "mozilla/ipc/BackgroundUtils.h"
#include "mozilla/LoadInfo.h"
#include "mozilla/dom/ContentParent.h"

using namespace mozilla::dom;
using namespace mozilla::ipc;

#undef LOG
#define LOG(args) MOZ_LOG(gFTPLog, mozilla::LogLevel::Debug, args)

namespace mozilla {
namespace net {

FTPChannelParent::FTPChannelParent(const PBrowserOrId& aIframeEmbedding,
                                   nsILoadContext* aLoadContext,
                                   PBOverrideStatus aOverrideStatus)
    : mIPCClosed(false),
      mLoadContext(aLoadContext),
      mPBOverride(aOverrideStatus),
      mStatus(NS_OK),
      mDivertingFromChild(false),
      mDivertedOnStartRequest(false),
      mSuspendedForDiversion(false),
      mUseUTF8(false) {
  nsIProtocolHandler* handler;
  CallGetService(NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX "ftp", &handler);
  MOZ_ASSERT(handler, "no ftp handler");

  if (aIframeEmbedding.type() == PBrowserOrId::TPBrowserParent) {
    mTabParent =
        static_cast<dom::TabParent*>(aIframeEmbedding.get_PBrowserParent());
  }

  mEventQ = new ChannelEventQueue(static_cast<nsIParentChannel*>(this));
}

FTPChannelParent::~FTPChannelParent() { gFtpHandler->Release(); }

void FTPChannelParent::ActorDestroy(ActorDestroyReason why) {
  // We may still have refcount>0 if the channel hasn't called OnStopRequest
  // yet, but we must not send any more msgs to child.
  mIPCClosed = true;
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsISupports
//-----------------------------------------------------------------------------

NS_IMPL_ISUPPORTS(FTPChannelParent, nsIStreamListener, nsIParentChannel,
                  nsIInterfaceRequestor, nsIRequestObserver,
                  nsIChannelEventSink, nsIFTPChannelParentInternal)

//-----------------------------------------------------------------------------
// FTPChannelParent::PFTPChannelParent
//-----------------------------------------------------------------------------

//-----------------------------------------------------------------------------
// FTPChannelParent methods
//-----------------------------------------------------------------------------

bool FTPChannelParent::Init(const FTPChannelCreationArgs& aArgs) {
  switch (aArgs.type()) {
    case FTPChannelCreationArgs::TFTPChannelOpenArgs: {
      const FTPChannelOpenArgs& a = aArgs.get_FTPChannelOpenArgs();
      return DoAsyncOpen(a.uri(), a.startPos(), a.entityID(), a.uploadStream(),
                         a.loadInfo(), a.loadFlags());
    }
    case FTPChannelCreationArgs::TFTPChannelConnectArgs: {
      const FTPChannelConnectArgs& cArgs = aArgs.get_FTPChannelConnectArgs();
      return ConnectChannel(cArgs.channelId());
    }
    default:
      MOZ_ASSERT_UNREACHABLE("unknown open type");
      return false;
  }
}

bool FTPChannelParent::DoAsyncOpen(const URIParams& aURI,
                                   const uint64_t& aStartPos,
                                   const nsCString& aEntityID,
                                   const Maybe<IPCStream>& aUploadStream,
                                   const OptionalLoadInfoArgs& aLoadInfoArgs,
                                   const uint32_t& aLoadFlags) {
  nsresult rv;

  nsCOMPtr<nsIURI> uri = DeserializeURI(aURI);
  if (!uri) return false;

#ifdef DEBUG
  LOG(("FTPChannelParent DoAsyncOpen [this=%p uri=%s]\n", this,
       uri->GetSpecOrDefault().get()));
#endif

  nsCOMPtr<nsIIOService> ios(do_GetIOService(&rv));
  if (NS_FAILED(rv)) {
    return SendFailedAsyncOpen(rv);
  }

  nsCOMPtr<nsILoadInfo> loadInfo;
  rv = mozilla::ipc::LoadInfoArgsToLoadInfo(aLoadInfoArgs,
                                            getter_AddRefs(loadInfo));
  if (NS_FAILED(rv)) {
    return SendFailedAsyncOpen(rv);
  }

  OriginAttributes attrs;
  rv = loadInfo->GetOriginAttributes(&attrs);
  if (NS_FAILED(rv)) {
    return SendFailedAsyncOpen(rv);
  }

  nsCOMPtr<nsIChannel> chan;
  rv = NS_NewChannelInternal(getter_AddRefs(chan), uri, loadInfo, nullptr,
                             nullptr, nullptr, aLoadFlags, ios);

  if (NS_FAILED(rv)) return SendFailedAsyncOpen(rv);

  mChannel = chan;

  // later on mChannel may become an HTTP channel (we'll be redirected to one
  // if we're using a proxy), but for now this is safe
  nsFtpChannel* ftpChan = static_cast<nsFtpChannel*>(mChannel.get());

  if (mPBOverride != kPBOverride_Unset) {
    ftpChan->SetPrivate(mPBOverride == kPBOverride_Private ? true : false);
  }
  rv = ftpChan->SetNotificationCallbacks(this);
  if (NS_FAILED(rv)) return SendFailedAsyncOpen(rv);

  nsCOMPtr<nsIInputStream> upload = DeserializeIPCStream(aUploadStream);
  if (upload) {
    // contentType and contentLength are ignored
    rv = ftpChan->SetUploadStream(upload, EmptyCString(), 0);
    if (NS_FAILED(rv)) return SendFailedAsyncOpen(rv);
  }

  rv = ftpChan->ResumeAt(aStartPos, aEntityID);
  if (NS_FAILED(rv)) return SendFailedAsyncOpen(rv);

  rv = ftpChan->AsyncOpen(this);

  if (NS_FAILED(rv)) return SendFailedAsyncOpen(rv);

  return true;
}

bool FTPChannelParent::ConnectChannel(const uint32_t& channelId) {
  nsresult rv;

  LOG(("Looking for a registered channel [this=%p, id=%d]", this, channelId));

  nsCOMPtr<nsIChannel> channel;
  rv = NS_LinkRedirectChannels(channelId, this, getter_AddRefs(channel));
  if (NS_SUCCEEDED(rv)) mChannel = channel;

  LOG(("  found channel %p, rv=%08" PRIx32, mChannel.get(),
       static_cast<uint32_t>(rv)));

  return true;
}

mozilla::ipc::IPCResult FTPChannelParent::RecvCancel(const nsresult& status) {
  if (mChannel) mChannel->Cancel(status);

  return IPC_OK();
}

mozilla::ipc::IPCResult FTPChannelParent::RecvSuspend() {
  if (mChannel) {
    mChannel->Suspend();
  }
  return IPC_OK();
}

mozilla::ipc::IPCResult FTPChannelParent::RecvResume() {
  if (mChannel) {
    mChannel->Resume();
  }
  return IPC_OK();
}

class FTPDivertDataAvailableEvent : public MainThreadChannelEvent {
 public:
  FTPDivertDataAvailableEvent(FTPChannelParent* aParent, const nsCString& data,
                              const uint64_t& offset, const uint32_t& count)
      : mParent(aParent), mData(data), mOffset(offset), mCount(count) {}

  void Run() override {
    mParent->DivertOnDataAvailable(mData, mOffset, mCount);
  }

 private:
  FTPChannelParent* mParent;
  nsCString mData;
  uint64_t mOffset;
  uint32_t mCount;
};

mozilla::ipc::IPCResult FTPChannelParent::RecvDivertOnDataAvailable(
    const nsCString& data, const uint64_t& offset, const uint32_t& count) {
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot RecvDivertOnDataAvailable if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return IPC_FAIL_NO_REASON(this);
  }

  // Drop OnDataAvailables if the parent was canceled already.
  if (NS_FAILED(mStatus)) {
    return IPC_OK();
  }

  mEventQ->RunOrEnqueue(
      new FTPDivertDataAvailableEvent(this, data, offset, count));
  return IPC_OK();
}

void FTPChannelParent::DivertOnDataAvailable(const nsCString& data,
                                             const uint64_t& offset,
                                             const uint32_t& count) {
  LOG(("FTPChannelParent::DivertOnDataAvailable [this=%p]\n", this));

  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot DivertOnDataAvailable if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return;
  }

  // Drop OnDataAvailables if the parent was canceled already.
  if (NS_FAILED(mStatus)) {
    return;
  }

  nsCOMPtr<nsIInputStream> stringStream;
  nsresult rv =
      NS_NewByteInputStream(getter_AddRefs(stringStream),
                            MakeSpan(data).To(count), NS_ASSIGNMENT_DEPEND);
  if (NS_FAILED(rv)) {
    if (mChannel) {
      mChannel->Cancel(rv);
    }
    mStatus = rv;
    return;
  }

  AutoEventEnqueuer ensureSerialDispatch(mEventQ);

  rv = OnDataAvailable(mChannel, nullptr, stringStream, offset, count);

  stringStream->Close();
  if (NS_FAILED(rv)) {
    if (mChannel) {
      mChannel->Cancel(rv);
    }
    mStatus = rv;
  }
}

class FTPDivertStopRequestEvent : public MainThreadChannelEvent {
 public:
  FTPDivertStopRequestEvent(FTPChannelParent* aParent,
                            const nsresult& statusCode)
      : mParent(aParent), mStatusCode(statusCode) {}

  void Run() override { mParent->DivertOnStopRequest(mStatusCode); }

 private:
  FTPChannelParent* mParent;
  nsresult mStatusCode;
};

mozilla::ipc::IPCResult FTPChannelParent::RecvDivertOnStopRequest(
    const nsresult& statusCode) {
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot RecvDivertOnStopRequest if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return IPC_FAIL_NO_REASON(this);
  }

  mEventQ->RunOrEnqueue(new FTPDivertStopRequestEvent(this, statusCode));
  return IPC_OK();
}

void FTPChannelParent::DivertOnStopRequest(const nsresult& statusCode) {
  LOG(("FTPChannelParent::DivertOnStopRequest [this=%p]\n", this));

  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot DivertOnStopRequest if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return;
  }

  // Honor the channel's status even if the underlying transaction completed.
  nsresult status = NS_FAILED(mStatus) ? mStatus : statusCode;

  // Reset fake pending status in case OnStopRequest has already been called.
  if (mChannel) {
    nsCOMPtr<nsIForcePendingChannel> forcePendingIChan =
        do_QueryInterface(mChannel);
    if (forcePendingIChan) {
      forcePendingIChan->ForcePending(false);
    }
  }

  AutoEventEnqueuer ensureSerialDispatch(mEventQ);
  OnStopRequest(mChannel, nullptr, status);
}

class FTPDivertCompleteEvent : public MainThreadChannelEvent {
 public:
  explicit FTPDivertCompleteEvent(FTPChannelParent* aParent)
      : mParent(aParent) {}

  void Run() override { mParent->DivertComplete(); }

 private:
  FTPChannelParent* mParent;
};

mozilla::ipc::IPCResult FTPChannelParent::RecvDivertComplete() {
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot RecvDivertComplete if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return IPC_FAIL_NO_REASON(this);
  }

  mEventQ->RunOrEnqueue(new FTPDivertCompleteEvent(this));
  return IPC_OK();
}

void FTPChannelParent::DivertComplete() {
  LOG(("FTPChannelParent::DivertComplete [this=%p]\n", this));

  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot DivertComplete if diverting is not set!");
    FailDiversion(NS_ERROR_UNEXPECTED);
    return;
  }

  nsresult rv = ResumeForDiversion();
  if (NS_WARN_IF(NS_FAILED(rv))) {
    FailDiversion(NS_ERROR_UNEXPECTED);
  }
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsIRequestObserver
//-----------------------------------------------------------------------------

NS_IMETHODIMP
FTPChannelParent::OnStartRequest(nsIRequest* aRequest) {
  LOG(("FTPChannelParent::OnStartRequest [this=%p]\n", this));

  if (mDivertingFromChild) {
    MOZ_RELEASE_ASSERT(mDivertToListener,
                       "Cannot divert if listener is unset!");
    return mDivertToListener->OnStartRequest(aRequest);
  }

  nsCOMPtr<nsIChannel> chan = do_QueryInterface(aRequest);
  MOZ_ASSERT(chan);
  NS_ENSURE_TRUE(chan, NS_ERROR_UNEXPECTED);

  // Send down any permissions which are relevant to this URL if we are
  // performing a document load.
  if (!mIPCClosed) {
    PContentParent* pcp = Manager()->Manager();
    MOZ_ASSERT(pcp, "We should have a manager if our IPC isn't closed");
    DebugOnly<nsresult> rv =
        static_cast<ContentParent*>(pcp)
            ->AboutToLoadHttpFtpWyciwygDocumentForChild(chan);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
  }

  int64_t contentLength;
  chan->GetContentLength(&contentLength);
  nsCString contentType;
  chan->GetContentType(contentType);

  nsCString entityID;
  nsCOMPtr<nsIResumableChannel> resChan = do_QueryInterface(aRequest);
  MOZ_ASSERT(
      resChan);  // both FTP and HTTP should implement nsIResumableChannel
  if (resChan) {
    resChan->GetEntityID(entityID);
  }

  PRTime lastModified = 0;
  nsCOMPtr<nsIFTPChannel> ftpChan = do_QueryInterface(aRequest);
  if (ftpChan) {
    ftpChan->GetLastModifiedTime(&lastModified);
  }
  nsCOMPtr<nsIHttpChannelInternal> httpChan = do_QueryInterface(aRequest);
  if (httpChan) {
    Unused << httpChan->GetLastModifiedTime(&lastModified);
  }

  URIParams uriparam;
  nsCOMPtr<nsIURI> uri;
  chan->GetURI(getter_AddRefs(uri));
  SerializeURI(uri, uriparam);

  if (mIPCClosed || !SendOnStartRequest(mStatus, contentLength, contentType,
                                        lastModified, entityID, uriparam)) {
    return NS_ERROR_UNEXPECTED;
  }

  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::OnStopRequest(nsIRequest* aRequest, nsISupports* aContext,
                                nsresult aStatusCode) {
  LOG(("FTPChannelParent::OnStopRequest: [this=%p status=%" PRIu32 "]\n", this,
       static_cast<uint32_t>(aStatusCode)));

  if (mDivertingFromChild) {
    MOZ_RELEASE_ASSERT(mDivertToListener,
                       "Cannot divert if listener is unset!");
    return mDivertToListener->OnStopRequest(aRequest, aContext, aStatusCode);
  }

  if (mIPCClosed || !SendOnStopRequest(aStatusCode, mErrorMsg, mUseUTF8)) {
    return NS_ERROR_UNEXPECTED;
  }

  return NS_OK;
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsIStreamListener
//-----------------------------------------------------------------------------

NS_IMETHODIMP
FTPChannelParent::OnDataAvailable(nsIRequest* aRequest, nsISupports* aContext,
                                  nsIInputStream* aInputStream,
                                  uint64_t aOffset, uint32_t aCount) {
  LOG(("FTPChannelParent::OnDataAvailable [this=%p]\n", this));

  if (mDivertingFromChild) {
    MOZ_RELEASE_ASSERT(mDivertToListener,
                       "Cannot divert if listener is unset!");
    return mDivertToListener->OnDataAvailable(aRequest, aContext, aInputStream,
                                              aOffset, aCount);
  }

  nsCString data;
  nsresult rv = NS_ReadInputStreamToString(aInputStream, data, aCount);
  if (NS_FAILED(rv)) return rv;

  if (mIPCClosed || !SendOnDataAvailable(mStatus, data, aOffset, aCount))
    return NS_ERROR_UNEXPECTED;

  return NS_OK;
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsIParentChannel
//-----------------------------------------------------------------------------

NS_IMETHODIMP
FTPChannelParent::SetParentListener(HttpChannelParentListener* aListener) {
  // Do not need ptr to HttpChannelParentListener.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::NotifyChannelClassifierProtectionDisabled(
    uint32_t aAcceptedReason) {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::NotifyCookieAllowed() {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::NotifyCookieBlocked(uint32_t aRejectedReason) {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::NotifyTrackingResource(bool aIsThirdParty) {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::NotifyFlashPluginStateChanged(
    nsIHttpChannel::FlashPluginState aState) {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::SetClassifierMatchedInfo(const nsACString& aList,
                                           const nsACString& aProvider,
                                           const nsACString& aFullHash) {
  // One day, this should probably be filled in.
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::Delete() {
  if (mIPCClosed || !SendDeleteSelf()) return NS_ERROR_UNEXPECTED;

  return NS_OK;
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsIInterfaceRequestor
//-----------------------------------------------------------------------------

NS_IMETHODIMP
FTPChannelParent::GetInterface(const nsIID& uuid, void** result) {
  if (uuid.Equals(NS_GET_IID(nsIAuthPromptProvider)) ||
      uuid.Equals(NS_GET_IID(nsISecureBrowserUI))) {
    if (mTabParent) {
      return mTabParent->QueryInterface(uuid, result);
    }
  } else if (uuid.Equals(NS_GET_IID(nsIAuthPrompt)) ||
             uuid.Equals(NS_GET_IID(nsIAuthPrompt2))) {
    nsCOMPtr<nsIAuthPromptProvider> provider(do_QueryObject(mTabParent));
    if (provider) {
      return provider->GetAuthPrompt(nsIAuthPromptProvider::PROMPT_NORMAL, uuid,
                                     result);
    }
  }

  // Only support nsILoadContext if child channel's callbacks did too
  if (uuid.Equals(NS_GET_IID(nsILoadContext)) && mLoadContext) {
    nsCOMPtr<nsILoadContext> copy = mLoadContext;
    copy.forget(result);
    return NS_OK;
  }

  return QueryInterface(uuid, result);
}

nsresult FTPChannelParent::ResumeChannelInternalIfPossible() {
  nsCOMPtr<nsIChannelWithDivertableParentListener> chan =
      do_QueryInterface(mChannel);
  if (chan) {
    return chan->ResumeInternal();
  }
  return mChannel->Resume();
}

//-----------------------------------------------------------------------------
// FTPChannelParent::ADivertableParentChannel
//-----------------------------------------------------------------------------
nsresult FTPChannelParent::SuspendForDiversion() {
  MOZ_ASSERT(mChannel);
  if (NS_WARN_IF(mDivertingFromChild)) {
    MOZ_ASSERT(!mDivertingFromChild, "Already suspended for diversion!");
    return NS_ERROR_UNEXPECTED;
  }

  // MessageDiversionStarted call will suspend mEventQ as many times as the
  // channel has been suspended, so that channel and this queue are in sync.
  nsCOMPtr<nsIChannelWithDivertableParentListener> chan =
      do_QueryInterface(mChannel);
  if (chan) {
    chan->MessageDiversionStarted(this);
  }

  // We need to suspend only nsHttp/FTPChannel (i.e. we should not suspend
  // mEventQ). Therefore we call mChannel->SuspendInternal() and not
  // mChannel->Suspend().
  // We are suspending only nsHttp/FTPChannel here because we want to stop
  // OnDataAvailable until diversion is over. At the same time we should
  // send the diverted OnDataAvailable-s to the listeners and not queue them
  // in mEventQ.
  // Try suspending the channel. Allow it to fail, since OnStopRequest may have
  // been called and thus the channel may not be pending.
  nsresult rv;
  if (chan) {
    rv = chan->SuspendInternal();
  } else {
    rv = mChannel->Suspend();
  }

  MOZ_ASSERT(NS_SUCCEEDED(rv) || rv == NS_ERROR_NOT_AVAILABLE);
  mSuspendedForDiversion = NS_SUCCEEDED(rv);

  // Once this is set, no more OnStart/OnData/OnStop callbacks should be sent
  // to the child.
  mDivertingFromChild = true;

  return NS_OK;
}

/* private, supporting function for ADivertableParentChannel */
nsresult FTPChannelParent::ResumeForDiversion() {
  MOZ_ASSERT(mChannel);
  MOZ_ASSERT(mDivertToListener);
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot ResumeForDiversion if not diverting!");
    return NS_ERROR_UNEXPECTED;
  }

  nsCOMPtr<nsIChannelWithDivertableParentListener> chan =
      do_QueryInterface(mChannel);
  if (chan) {
    chan->MessageDiversionStop();
  }

  if (mSuspendedForDiversion) {
    nsresult rv = ResumeChannelInternalIfPossible();
    if (NS_WARN_IF(NS_FAILED(rv))) {
      FailDiversion(NS_ERROR_UNEXPECTED, true);
      return rv;
    }
    mSuspendedForDiversion = false;
  }

  // Delete() will tear down IPDL, but ref from underlying nsFTPChannel will
  // keep us alive if there's more data to be delivered to listener.
  if (NS_WARN_IF(NS_FAILED(Delete()))) {
    FailDiversion(NS_ERROR_UNEXPECTED);
    return NS_ERROR_UNEXPECTED;
  }
  return NS_OK;
}

nsresult FTPChannelParent::SuspendMessageDiversion() {
  // This only need to suspend message queue.
  mEventQ->Suspend();
  return NS_OK;
}

nsresult FTPChannelParent::ResumeMessageDiversion() {
  // This only need to resumes message queue.
  mEventQ->Resume();
  return NS_OK;
}

nsresult FTPChannelParent::CancelDiversion() {
  // Only HTTP channels can have child-process-sourced-data that's long-lived
  // so this isn't currently relevant for FTP channels and there is nothing to
  // do.
  return NS_OK;
}

void FTPChannelParent::DivertTo(nsIStreamListener* aListener) {
  MOZ_ASSERT(aListener);
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot DivertTo new listener if diverting is not set!");
    return;
  }

  if (NS_WARN_IF(mIPCClosed || !SendFlushedForDiversion())) {
    FailDiversion(NS_ERROR_UNEXPECTED);
    return;
  }

  mDivertToListener = aListener;

  // Call OnStartRequest and SendDivertMessages asynchronously to avoid
  // reentering client context.
  NS_DispatchToCurrentThread(
      NewRunnableMethod("net::FTPChannelParent::StartDiversion", this,
                        &FTPChannelParent::StartDiversion));
}

void FTPChannelParent::StartDiversion() {
  if (NS_WARN_IF(!mDivertingFromChild)) {
    MOZ_ASSERT(mDivertingFromChild,
               "Cannot StartDiversion if diverting is not set!");
    return;
  }

  // Fake pending status in case OnStopRequest has already been called.
  if (mChannel) {
    nsCOMPtr<nsIForcePendingChannel> forcePendingIChan =
        do_QueryInterface(mChannel);
    if (forcePendingIChan) {
      forcePendingIChan->ForcePending(true);
    }
  }

  {
    AutoEventEnqueuer ensureSerialDispatch(mEventQ);
    // Call OnStartRequest for the "DivertTo" listener.
    nsresult rv = OnStartRequest(mChannel);
    if (NS_FAILED(rv)) {
      if (mChannel) {
        mChannel->Cancel(rv);
      }
      mStatus = rv;
      return;
    }
  }

  // After OnStartRequest has been called, tell FTPChannelChild to divert the
  // OnDataAvailables and OnStopRequest to this FTPChannelParent.
  if (NS_WARN_IF(mIPCClosed || !SendDivertMessages())) {
    FailDiversion(NS_ERROR_UNEXPECTED);
    return;
  }
}

class FTPFailDiversionEvent : public Runnable {
 public:
  FTPFailDiversionEvent(FTPChannelParent* aChannelParent, nsresult aErrorCode,
                        bool aSkipResume)
      : Runnable("net::FTPFailDiversionEvent"),
        mChannelParent(aChannelParent),
        mErrorCode(aErrorCode),
        mSkipResume(aSkipResume) {
    MOZ_RELEASE_ASSERT(aChannelParent);
    MOZ_RELEASE_ASSERT(NS_FAILED(aErrorCode));
  }
  NS_IMETHOD Run() override {
    mChannelParent->NotifyDiversionFailed(mErrorCode, mSkipResume);
    return NS_OK;
  }

 private:
  RefPtr<FTPChannelParent> mChannelParent;
  nsresult mErrorCode;
  bool mSkipResume;
};

void FTPChannelParent::FailDiversion(nsresult aErrorCode, bool aSkipResume) {
  MOZ_RELEASE_ASSERT(NS_FAILED(aErrorCode));
  MOZ_RELEASE_ASSERT(mDivertingFromChild);
  MOZ_RELEASE_ASSERT(mDivertToListener);
  MOZ_RELEASE_ASSERT(mChannel);

  NS_DispatchToCurrentThread(
      new FTPFailDiversionEvent(this, aErrorCode, aSkipResume));
}

void FTPChannelParent::NotifyDiversionFailed(nsresult aErrorCode,
                                             bool aSkipResume) {
  MOZ_RELEASE_ASSERT(NS_FAILED(aErrorCode));
  MOZ_RELEASE_ASSERT(mDivertingFromChild);
  MOZ_RELEASE_ASSERT(mDivertToListener);
  MOZ_RELEASE_ASSERT(mChannel);

  mChannel->Cancel(aErrorCode);
  nsCOMPtr<nsIForcePendingChannel> forcePendingIChan =
      do_QueryInterface(mChannel);
  if (forcePendingIChan) {
    forcePendingIChan->ForcePending(false);
  }

  bool isPending = false;
  nsresult rv = mChannel->IsPending(&isPending);
  MOZ_RELEASE_ASSERT(NS_SUCCEEDED(rv));

  // Resume only we suspended earlier.
  if (mSuspendedForDiversion) {
    ResumeChannelInternalIfPossible();
  }
  // Channel has already sent OnStartRequest to the child, so ensure that we
  // call it here if it hasn't already been called.
  if (!mDivertedOnStartRequest) {
    nsCOMPtr<nsIForcePendingChannel> forcePendingIChan =
        do_QueryInterface(mChannel);
    if (forcePendingIChan) {
      forcePendingIChan->ForcePending(true);
    }
    mDivertToListener->OnStartRequest(mChannel);

    if (forcePendingIChan) {
      forcePendingIChan->ForcePending(false);
    }
  }
  // If the channel is pending, it will call OnStopRequest itself; otherwise, do
  // it here.
  if (!isPending) {
    mDivertToListener->OnStopRequest(mChannel, nullptr, aErrorCode);
  }
  mDivertToListener = nullptr;
  mChannel = nullptr;

  if (!mIPCClosed) {
    Unused << SendDeleteSelf();
  }
}

//-----------------------------------------------------------------------------
// FTPChannelParent::nsIChannelEventSink
//-----------------------------------------------------------------------------

NS_IMETHODIMP
FTPChannelParent::AsyncOnChannelRedirect(
    nsIChannel* oldChannel, nsIChannel* newChannel, uint32_t redirectFlags,
    nsIAsyncVerifyRedirectCallback* callback) {
  nsCOMPtr<nsIFTPChannel> ftpChan = do_QueryInterface(newChannel);
  if (!ftpChan) {
    // when FTP is set to use HTTP proxying, we wind up getting redirected to an
    // HTTP channel.
    nsCOMPtr<nsIHttpChannel> httpChan = do_QueryInterface(newChannel);
    if (!httpChan) return NS_ERROR_UNEXPECTED;
  }
  mChannel = newChannel;
  callback->OnRedirectVerifyCallback(NS_OK);
  return NS_OK;
}

NS_IMETHODIMP
FTPChannelParent::SetErrorMsg(const char* aMsg, bool aUseUTF8) {
  mErrorMsg = aMsg;
  mUseUTF8 = aUseUTF8;
  return NS_OK;
}

//---------------------
}  // namespace net
}  // namespace mozilla