1 files changed, 255 insertions, 0 deletions
diff --git a/pc/jsep_transport_collection.cc b/pc/jsep_transport_collection.cc
new file mode 100644
index 0000000000..ce068d99fc
--- /dev/null
+++ b/pc/jsep_transport_collection.cc
@@ -0,0 +1,255 @@
+/*
+ *  Copyright 2021 The WebRTC Project Authors. All rights reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "pc/jsep_transport_collection.h"
+
+#include <algorithm>
+#include <map>
+#include <type_traits>
+#include <utility>
+
+#include "p2p/base/p2p_constants.h"
+#include "rtc_base/logging.h"
+
+namespace webrtc {
+
+void BundleManager::Update(const cricket::SessionDescription* description) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  bundle_groups_.clear();
+  for (const cricket::ContentGroup* new_bundle_group :
+       description->GetGroupsByName(cricket::GROUP_TYPE_BUNDLE)) {
+    bundle_groups_.push_back(
+        std::make_unique<cricket::ContentGroup>(*new_bundle_group));
+    RTC_DLOG(LS_VERBOSE) << "Establishing bundle group "
+                         << new_bundle_group->ToString();
+  }
+  established_bundle_groups_by_mid_.clear();
+  for (const auto& bundle_group : bundle_groups_) {
+    for (const std::string& content_name : bundle_group->content_names()) {
+      established_bundle_groups_by_mid_[content_name] = bundle_group.get();
+    }
+  }
+}
+
+const cricket::ContentGroup* BundleManager::LookupGroupByMid(
+    const std::string& mid) const {
+  auto it = established_bundle_groups_by_mid_.find(mid);
+  return it != established_bundle_groups_by_mid_.end() ? it->second : nullptr;
+}
+bool BundleManager::IsFirstMidInGroup(const std::string& mid) const {
+  auto group = LookupGroupByMid(mid);
+  if (!group) {
+    return true;  // Unbundled MIDs are considered group leaders
+  }
+  return mid == *(group->FirstContentName());
+}
+
+cricket::ContentGroup* BundleManager::LookupGroupByMid(const std::string& mid) {
+  auto it = established_bundle_groups_by_mid_.find(mid);
+  return it != established_bundle_groups_by_mid_.end() ? it->second : nullptr;
+}
+
+void BundleManager::DeleteMid(const cricket::ContentGroup* bundle_group,
+                              const std::string& mid) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_LOG(LS_VERBOSE) << "Deleting mid " << mid << " from bundle group "
+                      << bundle_group->ToString();
+  // Remove the rejected content from the |bundle_group|.
+  // The const pointer arg is used to identify the group, we verify
+  // it before we use it to make a modification.
+  auto bundle_group_it = std::find_if(
+      bundle_groups_.begin(), bundle_groups_.end(),
+      [bundle_group](std::unique_ptr<cricket::ContentGroup>& group) {
+        return bundle_group == group.get();
+      });
+  RTC_DCHECK(bundle_group_it != bundle_groups_.end());
+  (*bundle_group_it)->RemoveContentName(mid);
+  established_bundle_groups_by_mid_.erase(
+      established_bundle_groups_by_mid_.find(mid));
+}
+
+void BundleManager::DeleteGroup(const cricket::ContentGroup* bundle_group) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DLOG(LS_VERBOSE) << "Deleting bundle group " << bundle_group->ToString();
+
+  auto bundle_group_it = std::find_if(
+      bundle_groups_.begin(), bundle_groups_.end(),
+      [bundle_group](std::unique_ptr<cricket::ContentGroup>& group) {
+        return bundle_group == group.get();
+      });
+  RTC_DCHECK(bundle_group_it != bundle_groups_.end());
+  auto mid_list = (*bundle_group_it)->content_names();
+  for (const auto& content_name : mid_list) {
+    DeleteMid(bundle_group, content_name);
+  }
+  bundle_groups_.erase(bundle_group_it);
+}
+
+void JsepTransportCollection::RegisterTransport(
+    const std::string& mid,
+    std::unique_ptr<cricket::JsepTransport> transport) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  SetTransportForMid(mid, transport.get());
+  jsep_transports_by_name_[mid] = std::move(transport);
+  RTC_DCHECK(IsConsistent());
+}
+
+std::vector<cricket::JsepTransport*> JsepTransportCollection::Transports() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  std::vector<cricket::JsepTransport*> result;
+  for (auto& kv : jsep_transports_by_name_) {
+    result.push_back(kv.second.get());
+  }
+  return result;
+}
+
+void JsepTransportCollection::DestroyAllTransports() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  for (const auto& jsep_transport : jsep_transports_by_name_) {
+    map_change_callback_(jsep_transport.first, nullptr);
+  }
+  jsep_transports_by_name_.clear();
+  RTC_DCHECK(IsConsistent());
+}
+
+const cricket::JsepTransport* JsepTransportCollection::GetTransportByName(
+    const std::string& transport_name) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = jsep_transports_by_name_.find(transport_name);
+  return (it == jsep_transports_by_name_.end()) ? nullptr : it->second.get();
+}
+
+cricket::JsepTransport* JsepTransportCollection::GetTransportByName(
+    const std::string& transport_name) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = jsep_transports_by_name_.find(transport_name);
+  return (it == jsep_transports_by_name_.end()) ? nullptr : it->second.get();
+}
+
+cricket::JsepTransport* JsepTransportCollection::GetTransportForMid(
+    const std::string& mid) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = mid_to_transport_.find(mid);
+  return it == mid_to_transport_.end() ? nullptr : it->second;
+}
+
+const cricket::JsepTransport* JsepTransportCollection::GetTransportForMid(
+    const std::string& mid) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  auto it = mid_to_transport_.find(mid);
+  return it == mid_to_transport_.end() ? nullptr : it->second;
+}
+
+bool JsepTransportCollection::SetTransportForMid(
+    const std::string& mid,
+    cricket::JsepTransport* jsep_transport) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DCHECK(jsep_transport);
+
+  auto it = mid_to_transport_.find(mid);
+  if (it != mid_to_transport_.end() && it->second == jsep_transport)
+    return true;
+
+  pending_mids_.push_back(mid);
+
+  // The map_change_callback must be called before destroying the
+  // transport, because it removes references to the transport
+  // in the RTP demuxer.
+  bool result = map_change_callback_(mid, jsep_transport);
+
+  if (it == mid_to_transport_.end()) {
+    mid_to_transport_.insert(std::make_pair(mid, jsep_transport));
+  } else {
+    auto old_transport = it->second;
+    it->second = jsep_transport;
+    MaybeDestroyJsepTransport(old_transport);
+  }
+  RTC_DCHECK(IsConsistent());
+  return result;
+}
+
+void JsepTransportCollection::RemoveTransportForMid(const std::string& mid) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  RTC_DCHECK(IsConsistent());
+  bool ret = map_change_callback_(mid, nullptr);
+  // Calling OnTransportChanged with nullptr should always succeed, since it is
+  // only expected to fail when adding media to a transport (not removing).
+  RTC_DCHECK(ret);
+
+  auto old_transport = GetTransportForMid(mid);
+  if (old_transport) {
+    mid_to_transport_.erase(mid);
+    MaybeDestroyJsepTransport(old_transport);
+  }
+  RTC_DCHECK(IsConsistent());
+}
+
+void JsepTransportCollection::RollbackTransports() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  for (auto&& mid : pending_mids_) {
+    RemoveTransportForMid(mid);
+  }
+  pending_mids_.clear();
+}
+
+void JsepTransportCollection::CommitTransports() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  pending_mids_.clear();
+}
+
+bool JsepTransportCollection::TransportInUse(
+    cricket::JsepTransport* jsep_transport) const {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  for (const auto& kv : mid_to_transport_) {
+    if (kv.second == jsep_transport) {
+      return true;
+    }
+  }
+  return false;
+}
+
+void JsepTransportCollection::MaybeDestroyJsepTransport(
+    cricket::JsepTransport* transport) {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  // Don't destroy the JsepTransport if there are still media sections referring
+  // to it.
+  if (TransportInUse(transport)) {
+    return;
+  }
+  for (const auto& it : jsep_transports_by_name_) {
+    if (it.second.get() == transport) {
+      jsep_transports_by_name_.erase(it.first);
+      state_change_callback_();
+      break;
+    }
+  }
+  RTC_DCHECK(IsConsistent());
+}
+
+bool JsepTransportCollection::IsConsistent() {
+  RTC_DCHECK_RUN_ON(&sequence_checker_);
+  for (const auto& it : jsep_transports_by_name_) {
+    if (!TransportInUse(it.second.get())) {
+      RTC_LOG(LS_ERROR) << "Transport registered with mid " << it.first
+                        << " is not in use, transport " << it.second.get();
+      return false;
+    }
+    const auto& lookup = mid_to_transport_.find(it.first);
+    if (lookup->second != it.second.get()) {
+      // Not an error, but unusual.
+      RTC_DLOG(LS_INFO) << "Note: Mid " << it.first << " was registered to "
+                        << it.second.get() << " but currently maps to "
+                        << lookup->second;
+    }
+  }
+  return true;
+}
+
+}  // namespace webrtc