1 files changed, 90 insertions, 0 deletions
diff --git a/dom/media/webrtc/jsapi/RTCStatsIdGenerator.cpp b/dom/media/webrtc/jsapi/RTCStatsIdGenerator.cpp
new file mode 100644
index 0000000000..8b0462e223
--- /dev/null
+++ b/dom/media/webrtc/jsapi/RTCStatsIdGenerator.cpp
@@ -0,0 +1,90 @@
+/* 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/. */
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+
+#include "RTCStatsIdGenerator.h"
+
+#include <iostream>
+
+#include "mozilla/RandomNum.h"
+#include "RTCStatsReport.h"
+#include "WebrtcGlobal.h"
+
+namespace mozilla {
+
+RTCStatsIdGenerator::RTCStatsIdGenerator()
+    : mSalt(RandomUint64().valueOr(0xa5a5a5a5)), mCounter(0) {}
+
+void RTCStatsIdGenerator::RewriteIds(
+    nsTArray<UniquePtr<dom::RTCStatsCollection>> aFromStats,
+    dom::RTCStatsCollection* aIntoReport) {
+  // Rewrite an Optional id
+  auto rewriteId = [&](dom::Optional<nsString>& id) {
+    if (id.WasPassed()) {
+      id.Value() = Id(id.Value());
+    }
+  };
+
+  auto rewriteIds = [&](auto& aList, auto... aParam) {
+    for (auto& stat : aList) {
+      (rewriteId(stat.*aParam), ...);
+    }
+  };
+
+  // Involves a lot of copying, since webidl dictionaries don't have
+  // move semantics. Oh well.
+
+  // Create a temporary to avoid double-rewriting any stats already in
+  // aIntoReport.
+  auto stats = MakeUnique<dom::RTCStatsCollection>();
+  dom::FlattenStats(std::move(aFromStats), stats.get());
+
+  using S = dom::RTCStats;
+  using ICPS = dom::RTCIceCandidatePairStats;
+  using RSS = dom::RTCRtpStreamStats;
+  using IRSS = dom::RTCInboundRtpStreamStats;
+  using ORSS = dom::RTCOutboundRtpStreamStats;
+  using RIRSS = dom::RTCRemoteInboundRtpStreamStats;
+  using RORSS = dom::RTCRemoteOutboundRtpStreamStats;
+
+  rewriteIds(stats->mIceCandidatePairStats, &S::mId, &ICPS::mLocalCandidateId,
+             &ICPS::mRemoteCandidateId);
+  rewriteIds(stats->mIceCandidateStats, &S::mId);
+  rewriteIds(stats->mInboundRtpStreamStats, &S::mId, &IRSS::mRemoteId,
+             &RSS::mCodecId);
+  rewriteIds(stats->mOutboundRtpStreamStats, &S::mId, &ORSS::mRemoteId,
+             &RSS::mCodecId);
+  rewriteIds(stats->mRemoteInboundRtpStreamStats, &S::mId, &RIRSS::mLocalId,
+             &RSS::mCodecId);
+  rewriteIds(stats->mRemoteOutboundRtpStreamStats, &S::mId, &RORSS::mLocalId,
+             &RSS::mCodecId);
+  rewriteIds(stats->mCodecStats, &S::mId);
+  rewriteIds(stats->mRtpContributingSourceStats, &S::mId);
+  rewriteIds(stats->mTrickledIceCandidateStats, &S::mId);
+  rewriteIds(stats->mDataChannelStats, &S::mId);
+
+  dom::MergeStats(std::move(stats), aIntoReport);
+}
+
+nsString RTCStatsIdGenerator::Id(const nsString& aKey) {
+  if (!aKey.Length()) {
+    MOZ_ASSERT(aKey.Length(), "Stats IDs should never be empty.");
+    return aKey;
+  }
+  if (mAllocated.find(aKey) == mAllocated.end()) {
+    mAllocated[aKey] = Generate();
+  }
+  return mAllocated[aKey];
+}
+
+nsString RTCStatsIdGenerator::Generate() {
+  auto random = RandomUint64().valueOr(0x1a22);
+  auto idNum = static_cast<uint32_t>(mSalt ^ ((mCounter++ << 16) | random));
+  nsString id;
+  id.AppendInt(idNum, 16);  // Append as hex
+  return id;
+}
+
+}  // namespace mozilla