tor-browser

The Tor Browser
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RTCStatsIdGenerator.cpp (3031B)

      1 /* This Source Code Form is subject to the terms of the Mozilla Public
      2 * License, v. 2.0. If a copy of the MPL was not distributed with this file,
      3 * You can obtain one at http://mozilla.org/MPL/2.0/. */
      4 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
      5 /* vim: set ts=8 sts=2 et sw=2 tw=80: */
      6 
      7 #include "RTCStatsIdGenerator.h"
      8 
      9 #include "RTCStatsReport.h"
     10 #include "WebrtcGlobal.h"
     11 #include "mozilla/RandomNum.h"
     12 
     13 namespace mozilla {
     14 
     15 RTCStatsIdGenerator::RTCStatsIdGenerator()
     16    : mSalt(RandomUint64().valueOr(0xa5a5a5a5)), mCounter(0) {}
     17 
     18 void RTCStatsIdGenerator::RewriteIds(
     19    nsTArray<UniquePtr<dom::RTCStatsCollection>> aFromStats,
     20    dom::RTCStatsCollection* aIntoReport) {
     21  // Rewrite an Optional id
     22  auto rewriteId = [&](dom::Optional<nsString>& id) {
     23    if (id.WasPassed()) {
     24      id.Value() = Id(id.Value());
     25    }
     26  };
     27 
     28  auto rewriteIds = [&](auto& aList, auto... aParam) {
     29    for (auto& stat : aList) {
     30      (rewriteId(stat.*aParam), ...);
     31    }
     32  };
     33 
     34  // Involves a lot of copying, since webidl dictionaries don't have
     35  // move semantics. Oh well.
     36 
     37  // Create a temporary to avoid double-rewriting any stats already in
     38  // aIntoReport.
     39  auto stats = MakeUnique<dom::RTCStatsCollection>();
     40  dom::FlattenStats(std::move(aFromStats), stats.get());
     41 
     42  using S = dom::RTCStats;
     43  using ICPS = dom::RTCIceCandidatePairStats;
     44  using RSS = dom::RTCRtpStreamStats;
     45  using IRSS = dom::RTCInboundRtpStreamStats;
     46  using ORSS = dom::RTCOutboundRtpStreamStats;
     47  using RIRSS = dom::RTCRemoteInboundRtpStreamStats;
     48  using RORSS = dom::RTCRemoteOutboundRtpStreamStats;
     49 
     50  rewriteIds(stats->mIceCandidatePairStats, &S::mId, &ICPS::mLocalCandidateId,
     51             &ICPS::mRemoteCandidateId);
     52  rewriteIds(stats->mIceCandidateStats, &S::mId);
     53  rewriteIds(stats->mInboundRtpStreamStats, &S::mId, &IRSS::mRemoteId,
     54             &RSS::mCodecId);
     55  rewriteIds(stats->mOutboundRtpStreamStats, &S::mId, &ORSS::mRemoteId,
     56             &RSS::mCodecId);
     57  rewriteIds(stats->mRemoteInboundRtpStreamStats, &S::mId, &RIRSS::mLocalId,
     58             &RSS::mCodecId);
     59  rewriteIds(stats->mRemoteOutboundRtpStreamStats, &S::mId, &RORSS::mLocalId,
     60             &RSS::mCodecId);
     61  rewriteIds(stats->mCodecStats, &S::mId);
     62  rewriteIds(stats->mRtpContributingSourceStats, &S::mId);
     63  rewriteIds(stats->mTrickledIceCandidateStats, &S::mId);
     64  rewriteIds(stats->mDataChannelStats, &S::mId);
     65 
     66  dom::MergeStats(std::move(stats), aIntoReport);
     67 }
     68 
     69 nsString RTCStatsIdGenerator::Id(const nsString& aKey) {
     70  if (!aKey.Length()) {
     71    MOZ_ASSERT(aKey.Length(), "Stats IDs should never be empty.");
     72    return aKey;
     73  }
     74  if (mAllocated.find(aKey) == mAllocated.end()) {
     75    mAllocated[aKey] = Generate();
     76  }
     77  return mAllocated[aKey];
     78 }
     79 
     80 nsString RTCStatsIdGenerator::Generate() {
     81  auto random = RandomUint64().valueOr(0x1a22);
     82  auto idNum = static_cast<uint32_t>(mSalt ^ ((mCounter++ << 16) | random));
     83  nsString id;
     84  id.AppendInt(idNum, 16);  // Append as hex
     85  return id;
     86 }
     87 
     88 }  // namespace mozilla