netwerk/protocol/http/Http2Stream.cpp
author Adam Gashlin <agashlin@mozilla.com>
Wed, 31 Mar 2021 16:29:04 +0000
changeset 573907 32a9e6e145d6e3071c3993a20bb603a2f388722b
parent 567809 12a6bce21b413b088b01b8e419ac8a9aca63da1d
child 574699 cc59feb1fe6990c66ecb04c73866cdfde47cf891
permissions -rw-r--r--
Bug 1700870 - Explicitly convert path to UTF-8. r=application-update-reviewers,bytesized nsPrintfCString %S converts from UTF-16 to the ANSI code page, but we rely on the output string being UTF-8. Differential Revision: https://phabricator.services.mozilla.com/D110355

/* -*- 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/. */

// HttpLog.h should generally be included first
#include "HttpLog.h"

// Log on level :5, instead of default :4.
#undef LOG
#define LOG(args) LOG5(args)
#undef LOG_ENABLED
#define LOG_ENABLED() LOG5_ENABLED()

#include <algorithm>

#include "Http2Compression.h"
#include "Http2Session.h"
#include "Http2Stream.h"
#include "Http2Push.h"
#include "TunnelUtils.h"

#include "mozilla/BasePrincipal.h"
#include "mozilla/Telemetry.h"
#include "nsAlgorithm.h"
#include "nsHttp.h"
#include "nsHttpHandler.h"
#include "nsHttpRequestHead.h"
#include "nsIClassOfService.h"
#include "nsStandardURL.h"
#include "prnetdb.h"

namespace mozilla {
namespace net {

Http2Stream::Http2Stream(nsAHttpTransaction* httpTransaction,
                         Http2Session* session, int32_t priority,
                         uint64_t windowId)
    : mStreamID(0),
      mSession(session),
      mSegmentReader(nullptr),
      mSegmentWriter(nullptr),
      mUpstreamState(GENERATING_HEADERS),
      mState(IDLE),
      mRequestHeadersDone(0),
      mOpenGenerated(0),
      mAllHeadersReceived(0),
      mQueued(0),
      mSocketTransport(session->SocketTransport()),
      mCurrentForegroundTabOuterContentWindowId(windowId),
      mTransactionTabId(0),
      mTransaction(httpTransaction),
      mChunkSize(session->SendingChunkSize()),
      mRequestBlockedOnRead(0),
      mRecvdFin(0),
      mReceivedData(0),
      mRecvdReset(0),
      mSentReset(0),
      mCountAsActive(0),
      mSentFin(0),
      mSentWaitingFor(0),
      mSetTCPSocketBuffer(0),
      mBypassInputBuffer(0),
      mTxInlineFrameSize(Http2Session::kDefaultBufferSize),
      mTxInlineFrameUsed(0),
      mTxStreamFrameSize(0),
      mRequestBodyLenRemaining(0),
      mLocalUnacked(0),
      mBlockedOnRwin(false),
      mTotalSent(0),
      mTotalRead(0),
      mPushSource(nullptr),
      mAttempting0RTT(false),
      mIsTunnel(false),
      mPlainTextTunnel(false),
      mIsWebsocket(false) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  LOG1(("Http2Stream::Http2Stream %p trans=%p atrans=%p", this, trans,
        httpTransaction));

  mServerReceiveWindow = session->GetServerInitialStreamWindow();
  mClientReceiveWindow = session->PushAllowance();

  mTxInlineFrame = MakeUnique<uint8_t[]>(mTxInlineFrameSize);

  static_assert(nsISupportsPriority::PRIORITY_LOWEST <= kNormalPriority,
                "Lowest Priority should be less than kNormalPriority");

  // values of priority closer to 0 are higher priority for the priority
  // argument. This value is used as a group, which maps to a
  // weight that is related to the nsISupportsPriority that we are given.
  int32_t httpPriority;
  if (priority >= nsISupportsPriority::PRIORITY_LOWEST) {
    httpPriority = kWorstPriority;
  } else if (priority <= nsISupportsPriority::PRIORITY_HIGHEST) {
    httpPriority = kBestPriority;
  } else {
    httpPriority = kNormalPriority + priority;
  }
  MOZ_ASSERT(httpPriority >= 0);
  SetPriority(static_cast<uint32_t>(httpPriority));

  if (trans) {
    mTransactionTabId = trans->TopLevelOuterContentWindowId();
  }
}

Http2Stream::~Http2Stream() {
  ClearPushSource();
  ClearTransactionsBlockedOnTunnel();
  mStreamID = Http2Session::kDeadStreamID;

  LOG3(("Http2Stream::~Http2Stream %p", this));
}

void Http2Stream::ClearPushSource() {
  if (mPushSource) {
    mPushSource->SetConsumerStream(nullptr);
    mPushSource = nullptr;
  }
}

// ReadSegments() is used to write data down the socket. Generally, HTTP
// request data is pulled from the approriate transaction and
// converted to HTTP/2 data. Sometimes control data like a window-update is
// generated instead.

nsresult Http2Stream::ReadSegments(nsAHttpSegmentReader* reader, uint32_t count,
                                   uint32_t* countRead) {
  LOG3(("Http2Stream %p ReadSegments reader=%p count=%d state=%x", this, reader,
        count, mUpstreamState));

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  nsresult rv = NS_ERROR_UNEXPECTED;
  mRequestBlockedOnRead = 0;

  if (mRecvdFin || mRecvdReset) {
    // Don't transmit any request frames if the peer cannot respond
    LOG3(
        ("Http2Stream %p ReadSegments request stream aborted due to"
         " response side closure\n",
         this));
    return NS_ERROR_ABORT;
  }

  // avoid runt chunks if possible by anticipating
  // full data frames
  if (count > (mChunkSize + 8)) {
    uint32_t numchunks = count / (mChunkSize + 8);
    count = numchunks * (mChunkSize + 8);
  }

  switch (mUpstreamState) {
    case GENERATING_HEADERS:
    case GENERATING_BODY:
    case SENDING_BODY:
      // Call into the HTTP Transaction to generate the HTTP request
      // stream. That stream will show up in OnReadSegment().
      mSegmentReader = reader;
      rv = mTransaction->ReadSegments(this, count, countRead);
      mSegmentReader = nullptr;

      LOG3(("Http2Stream::ReadSegments %p trans readsegments rv %" PRIx32
            " read=%d\n",
            this, static_cast<uint32_t>(rv), *countRead));

      // Check to see if the transaction's request could be written out now.
      // If not, mark the stream for callback when writing can proceed.
      if (NS_SUCCEEDED(rv) && mUpstreamState == GENERATING_HEADERS &&
          !mRequestHeadersDone)
        mSession->TransactionHasDataToWrite(this);

      // mTxinlineFrameUsed represents any queued un-sent frame. It might
      // be 0 if there is no such frame, which is not a gurantee that we
      // don't have more request body to send - just that any data that was
      // sent comprised a complete HTTP/2 frame. Likewise, a non 0 value is
      // a queued, but complete, http/2 frame length.

      // Mark that we are blocked on read if the http transaction needs to
      // provide more of the request message body and there is nothing queued
      // for writing
      if (rv == NS_BASE_STREAM_WOULD_BLOCK && !mTxInlineFrameUsed) {
        LOG(("Http2Stream %p mRequestBlockedOnRead = 1", this));
        mRequestBlockedOnRead = 1;
      }

      // A transaction that had already generated its headers before it was
      // queued at the session level (due to concurrency concerns) may not call
      // onReadSegment off the ReadSegments() stack above.

      // When mTransaction->ReadSegments returns NS_BASE_STREAM_WOULD_BLOCK it
      // means it may have already finished providing all the request data
      // necessary to generate open, calling OnReadSegment will drive sending
      // the request; this may happen after dequeue of the stream.

      if (mUpstreamState == GENERATING_HEADERS &&
          (NS_SUCCEEDED(rv) || rv == NS_BASE_STREAM_WOULD_BLOCK)) {
        LOG3(
            ("Http2Stream %p ReadSegments forcing OnReadSegment call\n", this));
        uint32_t wasted = 0;
        mSegmentReader = reader;
        nsresult rv2 = OnReadSegment("", 0, &wasted);
        mSegmentReader = nullptr;

        LOG3(("  OnReadSegment returned 0x%08" PRIx32,
              static_cast<uint32_t>(rv2)));
        if (NS_SUCCEEDED(rv2)) {
          mRequestBlockedOnRead = 0;
        }
      }

      // If the sending flow control window is open (!mBlockedOnRwin) then
      // continue sending the request
      if (!mBlockedOnRwin && mOpenGenerated && !mTxInlineFrameUsed &&
          NS_SUCCEEDED(rv) && (!*countRead)) {
        MOZ_ASSERT(!mQueued);
        MOZ_ASSERT(mRequestHeadersDone);
        LOG3((
            "Http2Stream::ReadSegments %p 0x%X: Sending request data complete, "
            "mUpstreamState=%x\n",
            this, mStreamID, mUpstreamState));
        if (mSentFin) {
          ChangeState(UPSTREAM_COMPLETE);
        } else {
          GenerateDataFrameHeader(0, true);
          ChangeState(SENDING_FIN_STREAM);
          mSession->TransactionHasDataToWrite(this);
          rv = NS_BASE_STREAM_WOULD_BLOCK;
        }
      }
      break;

    case SENDING_FIN_STREAM:
      // We were trying to send the FIN-STREAM but were blocked from
      // sending it out - try again.
      if (!mSentFin) {
        mSegmentReader = reader;
        rv = TransmitFrame(nullptr, nullptr, false);
        mSegmentReader = nullptr;
        MOZ_ASSERT(NS_FAILED(rv) || !mTxInlineFrameUsed,
                   "Transmit Frame should be all or nothing");
        if (NS_SUCCEEDED(rv)) ChangeState(UPSTREAM_COMPLETE);
      } else {
        rv = NS_OK;
        mTxInlineFrameUsed = 0;  // cancel fin data packet
        ChangeState(UPSTREAM_COMPLETE);
      }

      *countRead = 0;

      // don't change OK to WOULD BLOCK. we are really done sending if OK
      break;

    case UPSTREAM_COMPLETE:
      *countRead = 0;
      rv = NS_OK;
      break;

    default:
      MOZ_ASSERT(false, "Http2Stream::ReadSegments unknown state");
      break;
  }

  return rv;
}

uint64_t Http2Stream::LocalUnAcked() {
  // reduce unacked by the amount of undelivered data
  // to help assert flow control
  uint64_t undelivered = mSimpleBuffer.Available();

  if (undelivered > mLocalUnacked) {
    return 0;
  }
  return mLocalUnacked - undelivered;
}

nsresult Http2Stream::BufferInput(uint32_t count, uint32_t* countWritten) {
  char buf[SimpleBufferPage::kSimpleBufferPageSize];
  if (SimpleBufferPage::kSimpleBufferPageSize < count) {
    count = SimpleBufferPage::kSimpleBufferPageSize;
  }

  mBypassInputBuffer = 1;
  nsresult rv = mSegmentWriter->OnWriteSegment(buf, count, countWritten);
  mBypassInputBuffer = 0;

  if (NS_SUCCEEDED(rv)) {
    rv = mSimpleBuffer.Write(buf, *countWritten);
    if (NS_FAILED(rv)) {
      MOZ_ASSERT(rv == NS_ERROR_OUT_OF_MEMORY);
      return NS_ERROR_OUT_OF_MEMORY;
    }
  }
  return rv;
}

bool Http2Stream::DeferCleanup(nsresult status) {
  // do not cleanup a stream that has data buffered for the transaction
  return (NS_SUCCEEDED(status) && mSimpleBuffer.Available());
}

// WriteSegments() is used to read data off the socket. Generally this is
// just a call through to the associated nsHttpTransaction for this stream
// for the remaining data bytes indicated by the current DATA frame.

nsresult Http2Stream::WriteSegments(nsAHttpSegmentWriter* writer,
                                    uint32_t count, uint32_t* countWritten) {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(!mSegmentWriter, "segment writer in progress");

  LOG3(("Http2Stream::WriteSegments %p count=%d state=%x", this, count,
        mUpstreamState));

  mSegmentWriter = writer;
  nsresult rv = mTransaction->WriteSegments(this, count, countWritten);

  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
    // consuming transaction won't take data. but we need to read it into a
    // buffer so that it won't block other streams. but we should not advance
    // the flow control window so that we'll eventually push back on the sender.

    // with tunnels you need to make sure that this is an underlying connction
    // established that can be meaningfully giving this signal
    bool doBuffer = true;
    if (mIsTunnel) {
      RefPtr<SpdyConnectTransaction> qiTrans(
          mTransaction->QuerySpdyConnectTransaction());
      if (qiTrans) {
        doBuffer = qiTrans->ConnectedReadyForInput();
      }
    }
    // stash this data
    if (doBuffer) {
      rv = BufferInput(count, countWritten);
      LOG3(("Http2Stream::WriteSegments %p Buffered %" PRIX32 " %d\n", this,
            static_cast<uint32_t>(rv), *countWritten));
    }
  }
  mSegmentWriter = nullptr;
  return rv;
}

nsresult Http2Stream::MakeOriginURL(const nsACString& origin,
                                    nsCOMPtr<nsIURI>& url) {
  nsAutoCString scheme;
  nsresult rv = net_ExtractURLScheme(origin, scheme);
  NS_ENSURE_SUCCESS(rv, rv);
  return MakeOriginURL(scheme, origin, url);
}

nsresult Http2Stream::MakeOriginURL(const nsACString& scheme,
                                    const nsACString& origin,
                                    nsCOMPtr<nsIURI>& url) {
  return NS_MutateURI(new nsStandardURL::Mutator())
      .Apply(NS_MutatorMethod(
          &nsIStandardURLMutator::Init, nsIStandardURL::URLTYPE_AUTHORITY,
          scheme.EqualsLiteral("http") ? NS_HTTP_DEFAULT_PORT
                                       : NS_HTTPS_DEFAULT_PORT,
          nsCString(origin), nullptr, nullptr, nullptr))
      .Finalize(url);
}

void Http2Stream::CreatePushHashKey(
    const nsCString& scheme, const nsCString& hostHeader,
    const mozilla::OriginAttributes& originAttributes, uint64_t serial,
    const nsACString& pathInfo, nsCString& outOrigin, nsCString& outKey) {
  nsCString fullOrigin = scheme;
  fullOrigin.AppendLiteral("://");
  fullOrigin.Append(hostHeader);

  nsCOMPtr<nsIURI> origin;
  nsresult rv = Http2Stream::MakeOriginURL(scheme, fullOrigin, origin);

  if (NS_SUCCEEDED(rv)) {
    rv = origin->GetAsciiSpec(outOrigin);
    outOrigin.Trim("/", false, true, false);
  }

  if (NS_FAILED(rv)) {
    // Fallback to plain text copy - this may end up behaving poorly
    outOrigin = fullOrigin;
  }

  outKey = outOrigin;
  outKey.AppendLiteral("/[");
  nsAutoCString suffix;
  originAttributes.CreateSuffix(suffix);
  outKey.Append(suffix);
  outKey.Append(']');
  outKey.AppendLiteral("/[http2.");
  outKey.AppendInt(serial);
  outKey.Append(']');
  outKey.Append(pathInfo);
}

nsresult Http2Stream::ParseHttpRequestHeaders(const char* buf, uint32_t avail,
                                              uint32_t* countUsed) {
  // Returns NS_OK even if the headers are incomplete
  // set mRequestHeadersDone flag if they are complete

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(mUpstreamState == GENERATING_HEADERS);
  MOZ_ASSERT(!mRequestHeadersDone);

  LOG3(("Http2Stream::ParseHttpRequestHeaders %p avail=%d state=%x", this,
        avail, mUpstreamState));

  mFlatHttpRequestHeaders.Append(buf, avail);
  nsHttpRequestHead* head = mTransaction->RequestHead();

  // We can use the simple double crlf because firefox is the
  // only client we are parsing
  int32_t endHeader = mFlatHttpRequestHeaders.Find("\r\n\r\n");

  if (endHeader == kNotFound) {
    // We don't have all the headers yet
    LOG3(
        ("Http2Stream::ParseHttpRequestHeaders %p "
         "Need more header bytes. Len = %d",
         this, mFlatHttpRequestHeaders.Length()));
    *countUsed = avail;
    return NS_OK;
  }

  // We have recvd all the headers, trim the local
  // buffer of the final empty line, and set countUsed to reflect
  // the whole header has been consumed.
  uint32_t oldLen = mFlatHttpRequestHeaders.Length();
  mFlatHttpRequestHeaders.SetLength(endHeader + 2);
  *countUsed = avail - (oldLen - endHeader) + 4;
  mRequestHeadersDone = 1;

  nsAutoCString authorityHeader;
  nsAutoCString hashkey;
  nsresult rv = head->GetHeader(nsHttp::Host, authorityHeader);
  if (NS_FAILED(rv)) {
    MOZ_ASSERT(false);
    return rv;
  }

  nsAutoCString requestURI;
  head->RequestURI(requestURI);

  mozilla::OriginAttributes originAttributes;
  mSocketTransport->GetOriginAttributes(&originAttributes);

  CreatePushHashKey(nsDependentCString(head->IsHTTPS() ? "https" : "http"),
                    authorityHeader, originAttributes, mSession->Serial(),
                    requestURI, mOrigin, hashkey);

  // check the push cache for GET
  if (head->IsGet()) {
    // from :scheme, :authority, :path
    nsIRequestContext* requestContext = mTransaction->RequestContext();
    SpdyPushCache* cache = nullptr;
    if (requestContext) {
      cache = requestContext->GetSpdyPushCache();
    }

    RefPtr<Http2PushedStreamWrapper> pushedStreamWrapper;
    Http2PushedStream* pushedStream = nullptr;

    // If a push stream is attached to the transaction via onPush, match only
    // with that one. This occurs when a push was made with in conjunction with
    // a nsIHttpPushListener
    nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
    if (trans && (pushedStreamWrapper = trans->TakePushedStream()) &&
        (pushedStream = pushedStreamWrapper->GetStream())) {
      if (pushedStream->mSession == mSession) {
        LOG3(("Pushed Stream match based on OnPush correlation %p",
              pushedStream));
      } else {
        LOG3(("Pushed Stream match failed due to stream mismatch %p %" PRId64
              " %" PRId64 "\n",
              pushedStream, pushedStream->mSession->Serial(),
              mSession->Serial()));
        pushedStream->OnPushFailed();
        pushedStream = nullptr;
      }
    }

    // we remove the pushedstream from the push cache so that
    // it will not be used for another GET. This does not destroy the
    // stream itself - that is done when the transactionhash is done with it.
    if (cache && !pushedStream) {
      pushedStream = cache->RemovePushedStreamHttp2(hashkey);
    }

    LOG3(
        ("Pushed Stream Lookup "
         "session=%p key=%s requestcontext=%p cache=%p hit=%p\n",
         mSession, hashkey.get(), requestContext, cache, pushedStream));

    if (pushedStream) {
      LOG3(("Pushed Stream Match located %p id=0x%X key=%s\n", pushedStream,
            pushedStream->StreamID(), hashkey.get()));
      pushedStream->SetConsumerStream(this);
      mPushSource = pushedStream;
      SetSentFin(true);
      AdjustPushedPriority();

      // There is probably pushed data buffered so trigger a read manually
      // as we can't rely on future network events to do it
      mSession->ConnectPushedStream(this);
      mOpenGenerated = 1;

      // if the "mother stream" had TRR, this one is a TRR stream too!
      RefPtr<nsHttpConnectionInfo> ci(Transaction()->ConnectionInfo());
      if (ci && ci->GetIsTrrServiceChannel()) {
        mSession->IncrementTrrCounter();
      }

      return NS_OK;
    }
  }
  return NS_OK;
}

// This is really a headers frame, but open is pretty clear from a workflow pov
nsresult Http2Stream::GenerateOpen() {
  // It is now OK to assign a streamID that we are assured will
  // be monotonically increasing amongst new streams on this
  // session
  mStreamID = mSession->RegisterStreamID(this);
  MOZ_ASSERT(mStreamID & 1, "Http2 Stream Channel ID must be odd");
  MOZ_ASSERT(!mOpenGenerated);

  mOpenGenerated = 1;

  nsHttpRequestHead* head = mTransaction->RequestHead();
  nsAutoCString requestURI;
  head->RequestURI(requestURI);
  LOG3(("Http2Stream %p Stream ID 0x%X [session=%p] for URI %s\n", this,
        mStreamID, mSession, requestURI.get()));

  if (mStreamID >= 0x80000000) {
    // streamID must fit in 31 bits. Evading This is theoretically possible
    // because stream ID assignment is asynchronous to stream creation
    // because of the protocol requirement that the new stream ID
    // be monotonically increasing. In reality this is really not possible
    // because new streams stop being added to a session with millions of
    // IDs still available and no race condition is going to bridge that gap;
    // so we can be comfortable on just erroring out for correctness in that
    // case.
    LOG3(("Stream assigned out of range ID: 0x%X", mStreamID));
    return NS_ERROR_UNEXPECTED;
  }

  // Now we need to convert the flat http headers into a set
  // of HTTP/2 headers by writing to mTxInlineFrame{sz}

  nsAutoCStringN<1025> compressedData;
  nsAutoCString authorityHeader;
  nsresult rv = head->GetHeader(nsHttp::Host, authorityHeader);
  if (NS_FAILED(rv)) {
    MOZ_ASSERT(false);
    return rv;
  }

  nsDependentCString scheme(head->IsHTTPS() ? "https" : "http");
  if (head->IsConnect()) {
    SpdyConnectTransaction* scTrans =
        mTransaction->QuerySpdyConnectTransaction();
    MOZ_ASSERT(scTrans);
    if (scTrans->IsWebsocket()) {
      mIsWebsocket = true;
    } else {
      mIsTunnel = true;
    }
    mRequestBodyLenRemaining = 0x0fffffffffffffffULL;

    if (mIsTunnel) {
      // Our normal authority has an implicit port, best to use an
      // explicit one with a tunnel
      nsHttpConnectionInfo* ci = mTransaction->ConnectionInfo();
      if (!ci) {
        return NS_ERROR_UNEXPECTED;
      }

      authorityHeader = ci->GetOrigin();
      authorityHeader.Append(':');
      authorityHeader.AppendInt(ci->OriginPort());
    }
  }

  nsAutoCString method;
  nsAutoCString path;
  head->Method(method);
  head->Path(path);
  bool useSimpleConnect = head->IsConnect();
  nsAutoCString protocol;
  if (mIsWebsocket) {
    useSimpleConnect = false;
    protocol.AppendLiteral("websocket");
  }
  rv = mSession->Compressor()->EncodeHeaderBlock(
      mFlatHttpRequestHeaders, method, path, authorityHeader, scheme, protocol,
      useSimpleConnect, compressedData);
  NS_ENSURE_SUCCESS(rv, rv);

  int64_t clVal = mSession->Compressor()->GetParsedContentLength();
  if (clVal != -1) {
    mRequestBodyLenRemaining = clVal;
  }

  // Determine whether to put the fin bit on the header frame or whether
  // to wait for a data packet to put it on.
  uint8_t firstFrameFlags = Http2Session::kFlag_PRIORITY;

  if (head->IsGet() || head->IsHead()) {
    // for GET and HEAD place the fin bit right on the
    // header packet

    SetSentFin(true);
    firstFrameFlags |= Http2Session::kFlag_END_STREAM;
  } else if (head->IsPost() || head->IsPut() || head->IsConnect()) {
    // place fin in a data frame even for 0 length messages for iterop
  } else if (!mRequestBodyLenRemaining) {
    // for other HTTP extension methods, rely on the content-length
    // to determine whether or not to put fin on headers
    SetSentFin(true);
    firstFrameFlags |= Http2Session::kFlag_END_STREAM;
  }

  // split this one HEADERS frame up into N HEADERS + CONTINUATION frames if it
  // exceeds the 2^14-1 limit for 1 frame. Do it by inserting header size gaps
  // in the existing frame for the new headers and for the first one a priority
  // field. There is no question this is ugly, but a 16KB HEADERS frame should
  // be a long tail event, so this is really just for correctness and a nop in
  // the base case.
  //

  MOZ_ASSERT(!mTxInlineFrameUsed);

  uint32_t dataLength = compressedData.Length();
  uint32_t maxFrameData =
      Http2Session::kMaxFrameData - 5;  // 5 bytes for priority
  uint32_t numFrames = 1;

  if (dataLength > maxFrameData) {
    numFrames +=
        ((dataLength - maxFrameData) + Http2Session::kMaxFrameData - 1) /
        Http2Session::kMaxFrameData;
    MOZ_ASSERT(numFrames > 1);
  }

  // note that we could still have 1 frame for 0 bytes of data. that's ok.

  uint32_t messageSize = dataLength;
  messageSize += Http2Session::kFrameHeaderBytes +
                 5;  // frame header + priority overhead in HEADERS frame
  messageSize += (numFrames - 1) *
                 Http2Session::kFrameHeaderBytes;  // frame header overhead in
                                                   // CONTINUATION frames

  EnsureBuffer(mTxInlineFrame, messageSize, mTxInlineFrameUsed,
               mTxInlineFrameSize);

  mTxInlineFrameUsed += messageSize;
  UpdatePriorityDependency();
  LOG1(
      ("Http2Stream %p Generating %d bytes of HEADERS for stream 0x%X with "
       "priority weight %u dep 0x%X frames %u uri=%s\n",
       this, mTxInlineFrameUsed, mStreamID, mPriorityWeight,
       mPriorityDependency, numFrames, requestURI.get()));

  uint32_t outputOffset = 0;
  uint32_t compressedDataOffset = 0;
  for (uint32_t idx = 0; idx < numFrames; ++idx) {
    uint32_t flags, frameLen;
    bool lastFrame = (idx == numFrames - 1);

    flags = 0;
    frameLen = maxFrameData;
    if (!idx) {
      flags |= firstFrameFlags;
      // Only the first frame needs the 4-byte offset
      maxFrameData = Http2Session::kMaxFrameData;
    }
    if (lastFrame) {
      frameLen = dataLength;
      flags |= Http2Session::kFlag_END_HEADERS;
    }
    dataLength -= frameLen;

    mSession->CreateFrameHeader(mTxInlineFrame.get() + outputOffset,
                                frameLen + (idx ? 0 : 5),
                                (idx) ? Http2Session::FRAME_TYPE_CONTINUATION
                                      : Http2Session::FRAME_TYPE_HEADERS,
                                flags, mStreamID);
    outputOffset += Http2Session::kFrameHeaderBytes;

    if (!idx) {
      uint32_t wireDep = PR_htonl(mPriorityDependency);
      memcpy(mTxInlineFrame.get() + outputOffset, &wireDep, 4);
      memcpy(mTxInlineFrame.get() + outputOffset + 4, &mPriorityWeight, 1);
      outputOffset += 5;
    }

    memcpy(mTxInlineFrame.get() + outputOffset,
           compressedData.BeginReading() + compressedDataOffset, frameLen);
    compressedDataOffset += frameLen;
    outputOffset += frameLen;
  }

  Telemetry::Accumulate(Telemetry::SPDY_SYN_SIZE, compressedData.Length());

  // The size of the input headers is approximate
  uint32_t ratio =
      compressedData.Length() * 100 /
      (11 + requestURI.Length() + mFlatHttpRequestHeaders.Length());

  mFlatHttpRequestHeaders.Truncate();
  Telemetry::Accumulate(Telemetry::SPDY_SYN_RATIO, ratio);
  return NS_OK;
}

void Http2Stream::AdjustInitialWindow() {
  // The default initial_window is sized for pushed streams. When we
  // generate a client pulled stream we want to disable flow control for
  // the stream with a window update. Do the same for pushed streams
  // when they connect to a pull.

  // >0 even numbered IDs are pushed streams.
  // odd numbered IDs are pulled streams.
  // 0 is the sink for a pushed stream.
  Http2Stream* stream = this;
  if (!mStreamID) {
    MOZ_ASSERT(mPushSource);
    if (!mPushSource) return;
    stream = mPushSource;
    MOZ_ASSERT(stream->mStreamID);
    MOZ_ASSERT(!(stream->mStreamID & 1));  // is a push stream

    // If the pushed stream has recvd a FIN, there is no reason to update
    // the window
    if (stream->RecvdFin() || stream->RecvdReset()) return;
  }

  if (stream->mState == RESERVED_BY_REMOTE) {
    // h2-14 prevents sending a window update in this state
    return;
  }

  // right now mClientReceiveWindow is the lower push limit
  // bump it up to the pull limit set by the channel or session
  // don't allow windows less than push
  uint32_t bump = 0;
  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  if (trans && trans->InitialRwin()) {
    bump = (trans->InitialRwin() > mClientReceiveWindow)
               ? (trans->InitialRwin() - mClientReceiveWindow)
               : 0;
  } else {
    MOZ_ASSERT(mSession->InitialRwin() >= mClientReceiveWindow);
    bump = mSession->InitialRwin() - mClientReceiveWindow;
  }

  LOG3(("AdjustInitialwindow increased flow control window %p 0x%X %u\n", this,
        stream->mStreamID, bump));
  if (!bump) {  // nothing to do
    return;
  }

  EnsureBuffer(mTxInlineFrame,
               mTxInlineFrameUsed + Http2Session::kFrameHeaderBytes + 4,
               mTxInlineFrameUsed, mTxInlineFrameSize);
  uint8_t* packet = mTxInlineFrame.get() + mTxInlineFrameUsed;
  mTxInlineFrameUsed += Http2Session::kFrameHeaderBytes + 4;

  mSession->CreateFrameHeader(packet, 4, Http2Session::FRAME_TYPE_WINDOW_UPDATE,
                              0, stream->mStreamID);

  mClientReceiveWindow += bump;
  bump = PR_htonl(bump);
  memcpy(packet + Http2Session::kFrameHeaderBytes, &bump, 4);
}

void Http2Stream::AdjustPushedPriority() {
  // >0 even numbered IDs are pushed streams. odd numbered IDs are pulled
  // streams. 0 is the sink for a pushed stream.

  if (mStreamID || !mPushSource) return;

  MOZ_ASSERT(mPushSource->mStreamID && !(mPushSource->mStreamID & 1));

  // If the pushed stream has recvd a FIN, there is no reason to update
  // the window
  if (mPushSource->RecvdFin() || mPushSource->RecvdReset()) return;

  // Ensure we pick up the right dependency to place the pushed stream under.
  UpdatePriorityDependency();

  EnsureBuffer(mTxInlineFrame,
               mTxInlineFrameUsed + Http2Session::kFrameHeaderBytes + 5,
               mTxInlineFrameUsed, mTxInlineFrameSize);
  uint8_t* packet = mTxInlineFrame.get() + mTxInlineFrameUsed;
  mTxInlineFrameUsed += Http2Session::kFrameHeaderBytes + 5;

  mSession->CreateFrameHeader(packet, 5, Http2Session::FRAME_TYPE_PRIORITY, 0,
                              mPushSource->mStreamID);

  mPushSource->SetPriorityDependency(mPriority, mPriorityDependency);
  uint32_t wireDep = PR_htonl(mPriorityDependency);
  memcpy(packet + Http2Session::kFrameHeaderBytes, &wireDep, 4);
  memcpy(packet + Http2Session::kFrameHeaderBytes + 4, &mPriorityWeight, 1);

  LOG3(("AdjustPushedPriority %p id 0x%X to dep %X weight %X\n", this,
        mPushSource->mStreamID, mPriorityDependency, mPriorityWeight));
}

void Http2Stream::UpdateTransportReadEvents(uint32_t count) {
  mTotalRead += count;
  if (!mSocketTransport) {
    return;
  }

  mTransaction->OnTransportStatus(mSocketTransport,
                                  NS_NET_STATUS_RECEIVING_FROM, mTotalRead);
}

void Http2Stream::UpdateTransportSendEvents(uint32_t count) {
  mTotalSent += count;

  // normally on non-windows platform we use TCP autotuning for
  // the socket buffers, and this works well (managing enough
  // buffers for BDP while conserving memory) for HTTP even when
  // it creates really deep queues. However this 'buffer bloat' is
  // a problem for http/2 because it ruins the low latency properties
  // necessary for PING and cancel to work meaningfully.
  //
  // If this stream represents a large upload, disable autotuning for
  // the session and cap the send buffers by default at 128KB.
  // (10Mbit/sec @ 100ms)
  //
  uint32_t bufferSize = gHttpHandler->SpdySendBufferSize();
  if ((mTotalSent > bufferSize) && !mSetTCPSocketBuffer) {
    mSetTCPSocketBuffer = 1;
    mSocketTransport->SetSendBufferSize(bufferSize);
  }

  if (mUpstreamState != SENDING_FIN_STREAM)
    mTransaction->OnTransportStatus(mSocketTransport, NS_NET_STATUS_SENDING_TO,
                                    mTotalSent);

  if (!mSentWaitingFor && !mRequestBodyLenRemaining) {
    mSentWaitingFor = 1;
    mTransaction->OnTransportStatus(mSocketTransport, NS_NET_STATUS_WAITING_FOR,
                                    0);
  }
}

nsresult Http2Stream::TransmitFrame(const char* buf, uint32_t* countUsed,
                                    bool forceCommitment) {
  // If TransmitFrame returns SUCCESS than all the data is sent (or at least
  // buffered at the session level), if it returns WOULD_BLOCK then none of
  // the data is sent.

  // You can call this function with no data and no out parameter in order to
  // flush internal buffers that were previously blocked on writing. You can
  // of course feed new data to it as well.

  LOG3(("Http2Stream::TransmitFrame %p inline=%d stream=%d", this,
        mTxInlineFrameUsed, mTxStreamFrameSize));
  if (countUsed) *countUsed = 0;

  if (!mTxInlineFrameUsed) {
    MOZ_ASSERT(!buf);
    return NS_OK;
  }

  MOZ_ASSERT(mTxInlineFrameUsed, "empty stream frame in transmit");
  MOZ_ASSERT(mSegmentReader, "TransmitFrame with null mSegmentReader");
  MOZ_ASSERT((buf && countUsed) || (!buf && !countUsed),
             "TransmitFrame arguments inconsistent");

  uint32_t transmittedCount;
  nsresult rv;

  // In the (relatively common) event that we have a small amount of data
  // split between the inlineframe and the streamframe, then move the stream
  // data into the inlineframe via copy in order to coalesce into one write.
  // Given the interaction with ssl this is worth the small copy cost.
  if (mTxStreamFrameSize && mTxInlineFrameUsed &&
      mTxStreamFrameSize < Http2Session::kDefaultBufferSize &&
      mTxInlineFrameUsed + mTxStreamFrameSize < mTxInlineFrameSize) {
    LOG3(("Coalesce Transmit"));
    memcpy(&mTxInlineFrame[mTxInlineFrameUsed], buf, mTxStreamFrameSize);
    if (countUsed) *countUsed += mTxStreamFrameSize;
    mTxInlineFrameUsed += mTxStreamFrameSize;
    mTxStreamFrameSize = 0;
  }

  rv = mSegmentReader->CommitToSegmentSize(
      mTxStreamFrameSize + mTxInlineFrameUsed, forceCommitment);

  if (rv == NS_BASE_STREAM_WOULD_BLOCK) {
    MOZ_ASSERT(!forceCommitment, "forceCommitment with WOULD_BLOCK");
    mSession->TransactionHasDataToWrite(this);
  }
  if (NS_FAILED(rv))  // this will include WOULD_BLOCK
    return rv;

  // This function calls mSegmentReader->OnReadSegment to report the actual
  // http/2 bytes through to the session object and then the HttpConnection
  // which calls the socket write function. It will accept all of the inline and
  // stream data because of the above 'commitment' even if it has to buffer

  rv = mSession->BufferOutput(reinterpret_cast<char*>(mTxInlineFrame.get()),
                              mTxInlineFrameUsed, &transmittedCount);
  LOG3(
      ("Http2Stream::TransmitFrame for inline BufferOutput session=%p "
       "stream=%p result %" PRIx32 " len=%d",
       mSession, this, static_cast<uint32_t>(rv), transmittedCount));

  MOZ_ASSERT(rv != NS_BASE_STREAM_WOULD_BLOCK,
             "inconsistent inline commitment result");

  if (NS_FAILED(rv)) return rv;

  MOZ_ASSERT(transmittedCount == mTxInlineFrameUsed,
             "inconsistent inline commitment count");

  Http2Session::LogIO(mSession, this, "Writing from Inline Buffer",
                      reinterpret_cast<char*>(mTxInlineFrame.get()),
                      transmittedCount);

  if (mTxStreamFrameSize) {
    if (!buf) {
      // this cannot happen
      MOZ_ASSERT(false,
                 "Stream transmit with null buf argument to "
                 "TransmitFrame()");
      LOG3(("Stream transmit with null buf argument to TransmitFrame()\n"));
      return NS_ERROR_UNEXPECTED;
    }

    // If there is already data buffered, just add to that to form
    // a single TLS Application Data Record - otherwise skip the memcpy
    if (mSession->AmountOfOutputBuffered()) {
      rv = mSession->BufferOutput(buf, mTxStreamFrameSize, &transmittedCount);
    } else {
      rv = mSession->OnReadSegment(buf, mTxStreamFrameSize, &transmittedCount);
    }

    LOG3(
        ("Http2Stream::TransmitFrame for regular session=%p "
         "stream=%p result %" PRIx32 " len=%d",
         mSession, this, static_cast<uint32_t>(rv), transmittedCount));

    MOZ_ASSERT(rv != NS_BASE_STREAM_WOULD_BLOCK,
               "inconsistent stream commitment result");

    if (NS_FAILED(rv)) return rv;

    MOZ_ASSERT(transmittedCount == mTxStreamFrameSize,
               "inconsistent stream commitment count");

    Http2Session::LogIO(mSession, this, "Writing from Transaction Buffer", buf,
                        transmittedCount);

    *countUsed += mTxStreamFrameSize;
  }

  if (!mAttempting0RTT) {
    mSession->FlushOutputQueue();
  }

  // calling this will trigger waiting_for if mRequestBodyLenRemaining is 0
  UpdateTransportSendEvents(mTxInlineFrameUsed + mTxStreamFrameSize);

  mTxInlineFrameUsed = 0;
  mTxStreamFrameSize = 0;

  return NS_OK;
}

void Http2Stream::ChangeState(enum upstreamStateType newState) {
  LOG3(("Http2Stream::ChangeState() %p from %X to %X", this, mUpstreamState,
        newState));
  mUpstreamState = newState;
}

void Http2Stream::GenerateDataFrameHeader(uint32_t dataLength, bool lastFrame) {
  LOG3(("Http2Stream::GenerateDataFrameHeader %p len=%d last=%d", this,
        dataLength, lastFrame));

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(!mTxInlineFrameUsed, "inline frame not empty");
  MOZ_ASSERT(!mTxStreamFrameSize, "stream frame not empty");

  uint8_t frameFlags = 0;
  if (lastFrame) {
    frameFlags |= Http2Session::kFlag_END_STREAM;
    if (dataLength) SetSentFin(true);
  }

  mSession->CreateFrameHeader(mTxInlineFrame.get(), dataLength,
                              Http2Session::FRAME_TYPE_DATA, frameFlags,
                              mStreamID);

  mTxInlineFrameUsed = Http2Session::kFrameHeaderBytes;
  mTxStreamFrameSize = dataLength;
}

// ConvertResponseHeaders is used to convert the response headers
// into HTTP/1 format and report some telemetry
nsresult Http2Stream::ConvertResponseHeaders(Http2Decompressor* decompressor,
                                             nsACString& aHeadersIn,
                                             nsACString& aHeadersOut,
                                             int32_t& httpResponseCode) {
  nsresult rv = decompressor->DecodeHeaderBlock(
      reinterpret_cast<const uint8_t*>(aHeadersIn.BeginReading()),
      aHeadersIn.Length(), aHeadersOut, false);
  if (NS_FAILED(rv)) {
    LOG3(("Http2Stream::ConvertResponseHeaders %p decode Error\n", this));
    return rv;
  }

  nsAutoCString statusString;
  decompressor->GetStatus(statusString);
  if (statusString.IsEmpty()) {
    LOG3(("Http2Stream::ConvertResponseHeaders %p Error - no status\n", this));
    return NS_ERROR_ILLEGAL_VALUE;
  }

  nsresult errcode;
  httpResponseCode = statusString.ToInteger(&errcode);

  // Ensure the :status is just an HTTP status code
  // https://tools.ietf.org/html/rfc7540#section-8.1.2.4
  // https://bugzilla.mozilla.org/show_bug.cgi?id=1352146
  nsAutoCString parsedStatusString;
  parsedStatusString.AppendInt(httpResponseCode);
  if (!parsedStatusString.Equals(statusString)) {
    LOG3(("Http2Stream::ConvertResposeHeaders %p status %s is not just a code",
          this, statusString.BeginReading()));
    // Results in stream reset with PROTOCOL_ERROR
    return NS_ERROR_ILLEGAL_VALUE;
  }

  LOG3(("Http2Stream::ConvertResponseHeaders %p response code %d\n", this,
        httpResponseCode));
  if (mIsTunnel) {
    LOG3(("Http2Stream %p Tunnel Response code %d", this, httpResponseCode));
    // 1xx response is simply skipeed and a final response is expected.
    // 2xx response needs to be encrypted.
    if ((httpResponseCode / 100) > 2) {
      MapStreamToPlainText();
    }
    if (MapStreamToHttpConnection(aHeadersOut, httpResponseCode)) {
      // Process transactions only if we have a final response, i.e., response
      // code >= 200.
      ClearTransactionsBlockedOnTunnel();
    }
  } else if (mIsWebsocket) {
    LOG3(("Http2Stream %p websocket response code %d", this, httpResponseCode));
    if (httpResponseCode == 200) {
      MapStreamToHttpConnection(aHeadersOut);
    }
  }

  if (httpResponseCode == 421) {
    // Origin Frame requires 421 to remove this origin from the origin set
    mSession->Received421(mTransaction->ConnectionInfo());
  }

  if (aHeadersIn.Length() && aHeadersOut.Length()) {
    Telemetry::Accumulate(Telemetry::SPDY_SYN_REPLY_SIZE, aHeadersIn.Length());
    uint32_t ratio = aHeadersIn.Length() * 100 / aHeadersOut.Length();
    Telemetry::Accumulate(Telemetry::SPDY_SYN_REPLY_RATIO, ratio);
  }

  // The decoding went ok. Now we can customize and clean up.

  aHeadersIn.Truncate();
  aHeadersOut.AppendLiteral("X-Firefox-Spdy: h2");
  aHeadersOut.AppendLiteral("\r\n\r\n");
  LOG(("decoded response headers are:\n%s", aHeadersOut.BeginReading()));
  if (mIsTunnel && !mPlainTextTunnel) {
    aHeadersOut.Truncate();
    LOG(("Http2Stream::ConvertHeaders %p 0x%X headers removed for tunnel\n",
         this, mStreamID));
  }
  return NS_OK;
}

// ConvertPushHeaders is used to convert the pushed request headers
// into HTTP/1 format and report some telemetry
nsresult Http2Stream::ConvertPushHeaders(Http2Decompressor* decompressor,
                                         nsACString& aHeadersIn,
                                         nsACString& aHeadersOut) {
  nsresult rv = decompressor->DecodeHeaderBlock(
      reinterpret_cast<const uint8_t*>(aHeadersIn.BeginReading()),
      aHeadersIn.Length(), aHeadersOut, true);
  if (NS_FAILED(rv)) {
    LOG3(("Http2Stream::ConvertPushHeaders %p Error\n", this));
    return rv;
  }

  nsCString method;
  decompressor->GetHost(mHeaderHost);
  decompressor->GetScheme(mHeaderScheme);
  decompressor->GetPath(mHeaderPath);

  if (mHeaderHost.IsEmpty() || mHeaderScheme.IsEmpty() ||
      mHeaderPath.IsEmpty()) {
    LOG3(
        ("Http2Stream::ConvertPushHeaders %p Error - missing required "
         "host=%s scheme=%s path=%s\n",
         this, mHeaderHost.get(), mHeaderScheme.get(), mHeaderPath.get()));
    return NS_ERROR_ILLEGAL_VALUE;
  }

  decompressor->GetMethod(method);
  if (!method.EqualsLiteral("GET")) {
    LOG3((
        "Http2Stream::ConvertPushHeaders %p Error - method not supported: %s\n",
        this, method.get()));
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  aHeadersIn.Truncate();
  LOG(("id 0x%X decoded push headers %s %s %s are:\n%s", mStreamID,
       mHeaderScheme.get(), mHeaderHost.get(), mHeaderPath.get(),
       aHeadersOut.BeginReading()));
  return NS_OK;
}

nsresult Http2Stream::ConvertResponseTrailers(Http2Decompressor* decompressor,
                                              nsACString& aTrailersIn) {
  LOG3(("Http2Stream::ConvertResponseTrailers %p", this));
  nsAutoCString flatTrailers;

  nsresult rv = decompressor->DecodeHeaderBlock(
      reinterpret_cast<const uint8_t*>(aTrailersIn.BeginReading()),
      aTrailersIn.Length(), flatTrailers, false);
  if (NS_FAILED(rv)) {
    LOG3(("Http2Stream::ConvertResponseTrailers %p decode Error", this));
    return rv;
  }

  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  if (trans) {
    trans->SetHttpTrailers(flatTrailers);
  } else {
    LOG3(("Http2Stream::ConvertResponseTrailers %p no trans", this));
  }

  return NS_OK;
}

void Http2Stream::Close(nsresult reason) {
  // In case we are connected to a push, make sure the push knows we are closed,
  // so it doesn't try to give us any more DATA that comes on it after our
  // close.
  ClearPushSource();

  mTransaction->Close(reason);
  mSession = nullptr;
}

void Http2Stream::SetResponseIsComplete() {
  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  if (trans) {
    trans->SetResponseIsComplete();
  }
}

void Http2Stream::SetAllHeadersReceived() {
  if (mAllHeadersReceived) {
    return;
  }

  if (mState == RESERVED_BY_REMOTE) {
    // pushed streams needs to wait until headers have
    // arrived to open up their window
    LOG3(("Http2Stream::SetAllHeadersReceived %p state OPEN from reserved\n",
          this));
    mState = OPEN;
    AdjustInitialWindow();
  }

  mAllHeadersReceived = 1;
}

bool Http2Stream::AllowFlowControlledWrite() {
  return (mSession->ServerSessionWindow() > 0) && (mServerReceiveWindow > 0);
}

void Http2Stream::UpdateServerReceiveWindow(int32_t delta) {
  mServerReceiveWindow += delta;

  if (mBlockedOnRwin && AllowFlowControlledWrite()) {
    LOG3(
        ("Http2Stream::UpdateServerReceived UnPause %p 0x%X "
         "Open stream window\n",
         this, mStreamID));
    mSession->TransactionHasDataToWrite(this);
  }
}

void Http2Stream::SetPriority(uint32_t newPriority) {
  int32_t httpPriority = static_cast<int32_t>(newPriority);
  if (httpPriority > kWorstPriority) {
    httpPriority = kWorstPriority;
  } else if (httpPriority < kBestPriority) {
    httpPriority = kBestPriority;
  }
  mPriority = static_cast<uint32_t>(httpPriority);
  mPriorityWeight = (nsISupportsPriority::PRIORITY_LOWEST + 1) -
                    (httpPriority - kNormalPriority);

  mPriorityDependency = 0;  // maybe adjusted later
}

void Http2Stream::SetPriorityDependency(uint32_t newPriority,
                                        uint32_t newDependency) {
  SetPriority(newPriority);
  mPriorityDependency = newDependency;
}

static uint32_t GetPriorityDependencyFromTransaction(nsHttpTransaction* trans) {
  MOZ_ASSERT(trans);

  uint32_t classFlags = trans->ClassOfService();

  if (classFlags & nsIClassOfService::UrgentStart) {
    return Http2Session::kUrgentStartGroupID;
  }

  if (classFlags & nsIClassOfService::Leader) {
    return Http2Session::kLeaderGroupID;
  }

  if (classFlags & nsIClassOfService::Follower) {
    return Http2Session::kFollowerGroupID;
  }

  if (classFlags & nsIClassOfService::Speculative) {
    return Http2Session::kSpeculativeGroupID;
  }

  if (classFlags & nsIClassOfService::Background) {
    return Http2Session::kBackgroundGroupID;
  }

  if (classFlags & nsIClassOfService::Unblocked) {
    return Http2Session::kOtherGroupID;
  }

  return Http2Session::kFollowerGroupID;  // unmarked followers
}

void Http2Stream::UpdatePriorityDependency() {
  if (!mSession->UseH2Deps()) {
    return;
  }

  nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
  if (!trans) {
    return;
  }

  // we create 6 fake dependency streams per session,
  // these streams are never opened with HEADERS. our first opened stream is 0xd
  // 3 depends 0, weight 200, leader class (kLeaderGroupID)
  // 5 depends 0, weight 100, other (kOtherGroupID)
  // 7 depends 0, weight 0, background (kBackgroundGroupID)
  // 9 depends 7, weight 0, speculative (kSpeculativeGroupID)
  // b depends 3, weight 0, follower class (kFollowerGroupID)
  // d depends 0, weight 240, urgent-start class (kUrgentStartGroupID)
  //
  // streams for leaders (html, js, css) depend on 3
  // streams for folowers (images) depend on b
  // default streams (xhr, async js) depend on 5
  // explicit bg streams (beacon, etc..) depend on 7
  // spculative bg streams depend on 9
  // urgent-start streams depend on d

  mPriorityDependency = GetPriorityDependencyFromTransaction(trans);

  if (gHttpHandler->ActiveTabPriority() &&
      mTransactionTabId != mCurrentForegroundTabOuterContentWindowId &&
      mPriorityDependency != Http2Session::kUrgentStartGroupID) {
    LOG3(
        ("Http2Stream::UpdatePriorityDependency %p "
         " depends on background group for trans %p\n",
         this, trans));
    mPriorityDependency = Http2Session::kBackgroundGroupID;

    nsHttp::NotifyActiveTabLoadOptimization();
  }

  LOG1(
      ("Http2Stream::UpdatePriorityDependency %p "
       "depends on stream 0x%X\n",
       this, mPriorityDependency));
}

void Http2Stream::TopLevelOuterContentWindowIdChanged(uint64_t windowId) {
  if (!mStreamID) {
    // For pushed streams, we ignore the direct call from the session and
    // instead let it come to the internal function from the pushed stream, so
    // we don't accidentally send two PRIORITY frames for the same stream.
    return;
  }

  TopLevelOuterContentWindowIdChangedInternal(windowId);
}

void Http2Stream::TopLevelOuterContentWindowIdChangedInternal(
    uint64_t windowId) {
  MOZ_ASSERT(gHttpHandler->ActiveTabPriority());

  LOG3(
      ("Http2Stream::TopLevelOuterContentWindowIdChanged "
       "%p windowId=%" PRIx64 "\n",
       this, windowId));

  mCurrentForegroundTabOuterContentWindowId = windowId;

  if (!mSession->UseH2Deps()) {
    return;
  }

  // Urgent start takes an absolute precedence, so don't
  // change mPriorityDependency here.
  if (mPriorityDependency == Http2Session::kUrgentStartGroupID) {
    return;
  }

  if (mTransactionTabId != mCurrentForegroundTabOuterContentWindowId) {
    mPriorityDependency = Http2Session::kBackgroundGroupID;
    LOG3(
        ("Http2Stream::TopLevelOuterContentWindowIdChanged %p "
         "move into background group.\n",
         this));

    nsHttp::NotifyActiveTabLoadOptimization();
  } else {
    nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
    if (!trans) {
      return;
    }

    mPriorityDependency = GetPriorityDependencyFromTransaction(trans);
    LOG3(
        ("Http2Stream::TopLevelOuterContentWindowIdChanged %p "
         "depends on stream 0x%X\n",
         this, mPriorityDependency));
  }

  uint32_t modifyStreamID = mStreamID;
  if (!modifyStreamID && mPushSource) {
    modifyStreamID = mPushSource->StreamID();
  }
  if (modifyStreamID) {
    mSession->SendPriorityFrame(modifyStreamID, mPriorityDependency,
                                mPriorityWeight);
  }
}

void Http2Stream::SetRecvdFin(bool aStatus) {
  mRecvdFin = aStatus ? 1 : 0;
  if (!aStatus) return;

  if (mState == OPEN || mState == RESERVED_BY_REMOTE) {
    mState = CLOSED_BY_REMOTE;
  } else if (mState == CLOSED_BY_LOCAL) {
    mState = CLOSED;
  }
}

void Http2Stream::SetSentFin(bool aStatus) {
  mSentFin = aStatus ? 1 : 0;
  if (!aStatus) return;

  if (mState == OPEN || mState == RESERVED_BY_REMOTE) {
    mState = CLOSED_BY_LOCAL;
  } else if (mState == CLOSED_BY_REMOTE) {
    mState = CLOSED;
  }
}

void Http2Stream::SetRecvdReset(bool aStatus) {
  mRecvdReset = aStatus ? 1 : 0;
  if (!aStatus) return;
  mState = CLOSED;
}

void Http2Stream::SetSentReset(bool aStatus) {
  mSentReset = aStatus ? 1 : 0;
  if (!aStatus) return;
  mState = CLOSED;
}

//-----------------------------------------------------------------------------
// nsAHttpSegmentReader
//-----------------------------------------------------------------------------

nsresult Http2Stream::OnReadSegment(const char* buf, uint32_t count,
                                    uint32_t* countRead) {
  LOG3(("Http2Stream::OnReadSegment %p count=%d state=%x", this, count,
        mUpstreamState));

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(mSegmentReader, "OnReadSegment with null mSegmentReader");

  nsresult rv = NS_ERROR_UNEXPECTED;
  uint32_t dataLength;

  switch (mUpstreamState) {
    case GENERATING_HEADERS:
      // The buffer is the HTTP request stream, including at least part of the
      // HTTP request header. This state's job is to build a HEADERS frame
      // from the header information. count is the number of http bytes
      // available (which may include more than the header), and in countRead we
      // return the number of those bytes that we consume (i.e. the portion that
      // are header bytes)

      if (!mRequestHeadersDone) {
        if (NS_FAILED(rv = ParseHttpRequestHeaders(buf, count, countRead))) {
          return rv;
        }
      }

      if (mRequestHeadersDone && !mOpenGenerated) {
        if (!mSession->TryToActivate(this)) {
          LOG3(("Http2Stream::OnReadSegment %p cannot activate now. queued.\n",
                this));
          return *countRead ? NS_OK : NS_BASE_STREAM_WOULD_BLOCK;
        }
        if (NS_FAILED(rv = GenerateOpen())) {
          return rv;
        }
      }

      LOG3(
          ("ParseHttpRequestHeaders %p used %d of %d. "
           "requestheadersdone = %d mOpenGenerated = %d\n",
           this, *countRead, count, mRequestHeadersDone, mOpenGenerated));
      if (mOpenGenerated) {
        SetHTTPState(OPEN);
        AdjustInitialWindow();
        // This version of TransmitFrame cannot block
        rv = TransmitFrame(nullptr, nullptr, true);
        ChangeState(GENERATING_BODY);
        break;
      }
      MOZ_ASSERT(*countRead == count,
                 "Header parsing not complete but unused data");
      break;

    case GENERATING_BODY:
      // if there is session flow control and either the stream window is active
      // and exhaused or the session window is exhausted then suspend
      if (!AllowFlowControlledWrite()) {
        *countRead = 0;
        LOG3(
            ("Http2Stream this=%p, id 0x%X request body suspended because "
             "remote window is stream=%" PRId64 " session=%" PRId64 ".\n",
             this, mStreamID, mServerReceiveWindow,
             mSession->ServerSessionWindow()));
        mBlockedOnRwin = true;
        return NS_BASE_STREAM_WOULD_BLOCK;
      }
      mBlockedOnRwin = false;

      // The chunk is the smallest of: availableData, configured chunkSize,
      // stream window, session window, or 14 bit framing limit.
      // Its amazing we send anything at all.
      dataLength = std::min(count, mChunkSize);

      if (dataLength > Http2Session::kMaxFrameData)
        dataLength = Http2Session::kMaxFrameData;

      if (dataLength > mSession->ServerSessionWindow())
        dataLength = static_cast<uint32_t>(mSession->ServerSessionWindow());

      if (dataLength > mServerReceiveWindow)
        dataLength = static_cast<uint32_t>(mServerReceiveWindow);

      LOG3(
          ("Http2Stream this=%p id 0x%X send calculation "
           "avail=%d chunksize=%d stream window=%" PRId64
           " session window=%" PRId64 " "
           "max frame=%d USING=%u\n",
           this, mStreamID, count, mChunkSize, mServerReceiveWindow,
           mSession->ServerSessionWindow(), Http2Session::kMaxFrameData,
           dataLength));

      mSession->DecrementServerSessionWindow(dataLength);
      mServerReceiveWindow -= dataLength;

      LOG3(("Http2Stream %p id 0x%x request len remaining %" PRId64 ", "
            "count avail %u, chunk used %u",
            this, mStreamID, mRequestBodyLenRemaining, count, dataLength));
      if (!dataLength && mRequestBodyLenRemaining) {
        return NS_BASE_STREAM_WOULD_BLOCK;
      }
      if (dataLength > mRequestBodyLenRemaining) {
        return NS_ERROR_UNEXPECTED;
      }
      mRequestBodyLenRemaining -= dataLength;
      GenerateDataFrameHeader(dataLength, !mRequestBodyLenRemaining);
      ChangeState(SENDING_BODY);
      [[fallthrough]];

    case SENDING_BODY:
      MOZ_ASSERT(mTxInlineFrameUsed, "OnReadSegment Send Data Header 0b");
      rv = TransmitFrame(buf, countRead, false);
      MOZ_ASSERT(NS_FAILED(rv) || !mTxInlineFrameUsed,
                 "Transmit Frame should be all or nothing");

      LOG3(("TransmitFrame() rv=%" PRIx32 " returning %d data bytes. "
            "Header is %d Body is %d.",
            static_cast<uint32_t>(rv), *countRead, mTxInlineFrameUsed,
            mTxStreamFrameSize));

      // normalize a partial write with a WOULD_BLOCK into just a partial write
      // as some code will take WOULD_BLOCK to mean an error with nothing
      // written (e.g. nsHttpTransaction::ReadRequestSegment()
      if (rv == NS_BASE_STREAM_WOULD_BLOCK && *countRead) rv = NS_OK;

      // If that frame was all sent, look for another one
      if (!mTxInlineFrameUsed) ChangeState(GENERATING_BODY);
      break;

    case SENDING_FIN_STREAM:
      MOZ_ASSERT(false, "resuming partial fin stream out of OnReadSegment");
      break;

    case UPSTREAM_COMPLETE:
      MOZ_ASSERT(mPushSource);
      rv = TransmitFrame(nullptr, nullptr, true);
      break;

    default:
      MOZ_ASSERT(false, "Http2Stream::OnReadSegment non-write state");
      break;
  }

  return rv;
}

//-----------------------------------------------------------------------------
// nsAHttpSegmentWriter
//-----------------------------------------------------------------------------

nsresult Http2Stream::OnWriteSegment(char* buf, uint32_t count,
                                     uint32_t* countWritten) {
  LOG3(("Http2Stream::OnWriteSegment %p count=%d state=%x 0x%X\n", this, count,
        mUpstreamState, mStreamID));

  MOZ_ASSERT(OnSocketThread(), "not on socket thread");
  MOZ_ASSERT(mSegmentWriter);

  if (mPushSource) {
    nsresult rv;
    rv = mPushSource->GetBufferedData(buf, count, countWritten);
    if (NS_FAILED(rv)) return rv;

    mSession->ConnectPushedStream(this);
    return NS_OK;
  }

  // sometimes we have read data from the network and stored it in a pipe
  // so that other streams can proceed when the gecko caller is not processing
  // data events fast enough and flow control hasn't caught up yet. This
  // gets the stored data out of that pipe
  if (!mBypassInputBuffer && mSimpleBuffer.Available()) {
    *countWritten = mSimpleBuffer.Read(buf, count);
    MOZ_ASSERT(*countWritten);
    LOG3(
        ("Http2Stream::OnWriteSegment read from flow control buffer %p %x %d\n",
         this, mStreamID, *countWritten));
    return NS_OK;
  }

  // read from the network
  return mSegmentWriter->OnWriteSegment(buf, count, countWritten);
}

/// connect tunnels

nsCString& Http2Stream::RegistrationKey() {
  if (mRegistrationKey.IsEmpty()) {
    MOZ_ASSERT(Transaction());
    MOZ_ASSERT(Transaction()->ConnectionInfo());

    mRegistrationKey = Transaction()->ConnectionInfo()->HashKey();
  }

  return mRegistrationKey;
}

void Http2Stream::ClearTransactionsBlockedOnTunnel() {
  MOZ_ASSERT(OnSocketThread(), "not on socket thread");

  if (!mIsTunnel) {
    return;
  }
  nsresult rv =
      gHttpHandler->ConnMgr()->ProcessPendingQ(mTransaction->ConnectionInfo());
  if (NS_FAILED(rv)) {
    LOG3(
        ("Http2Stream::ClearTransactionsBlockedOnTunnel %p\n"
         "  ProcessPendingQ failed: %08x\n",
         this, static_cast<uint32_t>(rv)));
  }
}

void Http2Stream::MapStreamToPlainText() {
  RefPtr<SpdyConnectTransaction> qiTrans(
      mTransaction->QuerySpdyConnectTransaction());
  MOZ_ASSERT(qiTrans);
  mPlainTextTunnel = true;
  qiTrans->ForcePlainText();
}

bool Http2Stream::MapStreamToHttpConnection(const nsACString& aFlat407Headers,
                                            int32_t aHttpResponseCode) {
  RefPtr<SpdyConnectTransaction> qiTrans(
      mTransaction->QuerySpdyConnectTransaction());
  MOZ_ASSERT(qiTrans);

  return qiTrans->MapStreamToHttpConnection(
      mSocketTransport, mTransaction->ConnectionInfo(), aFlat407Headers,
      mIsTunnel ? aHttpResponseCode : -1);
}

// -----------------------------------------------------------------------------
// mirror nsAHttpTransaction
// -----------------------------------------------------------------------------

bool Http2Stream::Do0RTT() {
  MOZ_ASSERT(mTransaction);
  mAttempting0RTT = mTransaction->Do0RTT();
  return mAttempting0RTT;
}

nsresult Http2Stream::Finish0RTT(bool aRestart, bool aAlpnChanged) {
  MOZ_ASSERT(mTransaction);
  mAttempting0RTT = false;
  // Instead of passing (aRestart, aAlpnChanged) here, we use aAlpnChanged for
  // both arguments because as long as the alpn token stayed the same, we can
  // just reuse what we have in our buffer to send instead of having to have
  // the transaction rewind and read it all over again. We only need to rewind
  // the transaction if we're switching to a new protocol, because our buffer
  // won't get used in that case.
  // ..
  // however, we send in the aRestart value to indicate that early data failed
  // for devtools purposes
  nsresult rv = mTransaction->Finish0RTT(aAlpnChanged, aAlpnChanged);
  if (aRestart) {
    nsHttpTransaction* trans = mTransaction->QueryHttpTransaction();
    if (trans) {
      trans->Refused0RTT();
    }
  }
  return rv;
}

nsresult Http2Stream::GetOriginAttributes(mozilla::OriginAttributes* oa) {
  if (!mSocketTransport) {
    return NS_ERROR_UNEXPECTED;
  }

  return mSocketTransport->GetOriginAttributes(oa);
}

}  // namespace net
}  // namespace mozilla