BWU Hotspot Responder(client) need to disconnect Hotspot when the session is done

PiperOrigin-RevId: 460577462

connections/implementation/base_bwu_handler.cc

@@ -75,6 +75,10 @@ void BaseBwuHandler::RevertInitiatorState(const std::string& upgrade_service_id,
   }
 }
 
+void BaseBwuHandler::RevertResponderState(const std::string& service_id) {
+  HandleRevertInitiatorStateForService(service_id);
+}
+
 }  // namespace connections
 }  // namespace nearby
 }  // namespace location

connections/implementation/base_bwu_handler.h

@@ -40,6 +40,10 @@ class BaseBwuHandler : public BwuHandler {
   void RevertInitiatorState() final;
   void RevertInitiatorState(const std::string& upgrade_service_id,
                             const std::string& endpoint_id) final;
+  // If BWU Medium is Hotspot. The client needs to disconnect from Hotspot, then
+  // it can restore the previous AP connection right away. The following method
+  // is only for Hotspot Client
+  void RevertResponderState(const std::string& service_id) final;
 
  protected:
   // Invoked by InitializeUpgradedMediumForEndpoint and RevertInitiatorState,

connections/implementation/bwu_handler.h

@@ -77,6 +77,8 @@ class BwuHandler {
   virtual void RevertInitiatorState(const std::string& service_id,
                                     const std::string& endpoint_id) = 0;
 
+  virtual void RevertResponderState(const std::string& service_id) = 0;
+
   // Called by the Responder to set up the upgraded medium for this endpoint (if
   // that hasn't already been done) using the UpgradePathInfo sent by the
   // Initiator, and returns a new EndpointChannel for the upgraded medium.

connections/implementation/bwu_manager.cc

@@ -374,12 +374,23 @@ void BwuManager::RevertBwuMediumForEndpoint(const std::string& service_id,
                     << endpoint_id;
   endpoint_id_to_bwu_medium_.erase(endpoint_id);
 
-  // If |service_id| isn't of the INITIATOR-upgrade format--for example, if this
-  // is called by the RESPONDER--there is no need to call RevertInitiatorState.
-  if (!IsInitiatorUpgradeServiceId(service_id)) return;
-
   BwuHandler* handler = GetHandlerForMedium(medium);
-  if (!handler) return;
+  if (!handler) {
+    NEARBY_LOGS(INFO) << "No BWU handler can be found for "
+                      << proto::connections::Medium_Name(medium);
+    return;
+  }
+  // If |service_id| isn't of the INITIATOR-upgrade format--for example, if this
+  // is called by the RESPONDER--there is no need to call RevertInitiatorState
+  // unless the BWU Medium is Hotspot. The client needs to disconnect from
+  // Hotspot, then it can restore the previous AP connection right away.
+  if (!IsInitiatorUpgradeServiceId(service_id)) {
+    if (medium == Medium::WIFI_HOTSPOT) {
+      handler->RevertResponderState(service_id);
+    }
+
+    return;
+  }
 
   handler->RevertInitiatorState(service_id, endpoint_id);
 }

connections/implementation/bwu_manager_test.cc

@@ -669,6 +669,59 @@ TEST_F(BwuManagerTest, InitiateBwu_Revert_OnUpgradeFailure_FlagDisabled) {
   EXPECT_TRUE(fake_web_rtc_bwu_handler_->handle_revert_calls().empty());
 }
 
+TEST_F(BwuManagerTest, InitiateBwu_Revert_OnDisconnect_Hotspot) {
+  FeatureFlags::GetMutableFlagsForTesting().support_multiple_bwu_mediums = true;
+
+  CreateInitialEndpoint(kServiceIdA, kEndpointId1, Medium::BLUETOOTH);
+
+  ExceptionOr<OfflineFrame> hotspot_path_available_frame =
+      parser::FromBytes(parser::ForBwuWifiHotspotPathAvailable(
+          /*ssid=*/"Direct-357a2d8c", /*password=*/"b592f7d3",
+          /*port=*/1234, /*gateway=*/"123.234.23.1", false));
+  OfflineFrame frame = hotspot_path_available_frame.result();
+  frame.set_version(OfflineFrame::V1);
+  auto* v1_frame = frame.mutable_v1();
+  auto* sub_frame = v1_frame->mutable_bandwidth_upgrade_negotiation();
+  sub_frame->set_event_type(
+      BandwidthUpgradeNegotiationFrame::UPGRADE_PATH_AVAILABLE);
+  auto* upgrade_path_info = sub_frame->mutable_upgrade_path_info();
+  upgrade_path_info->set_supports_client_introduction_ack(false);
+
+  bwu_manager_->OnIncomingFrame(frame, std::string(kEndpointId1), &client_,
+                                Medium::BLUETOOTH);
+  CountDownLatch latch(1);
+  bwu_manager_->OnEndpointDisconnect(&client_, (std::string)kServiceIdA,
+                                     std::string(kEndpointId1), latch);
+
+  ASSERT_EQ(fake_wifi_hotspot_bwu_handler_->handle_revert_calls().size(), 1u);
+}
+
+TEST_F(BwuManagerTest, InitiateBwu_Revert_OnDisconnect_Wlan) {
+  FeatureFlags::GetMutableFlagsForTesting().support_multiple_bwu_mediums = true;
+
+  CreateInitialEndpoint(kServiceIdA, kEndpointId1, Medium::BLUETOOTH);
+
+  ExceptionOr<OfflineFrame> wlan_path_available_frame = parser::FromBytes(
+      parser::ForBwuWifiLanPathAvailable(/*ip_address=*/"ABCD",
+                                         /*port=*/1234));
+  OfflineFrame frame = wlan_path_available_frame.result();
+  frame.set_version(OfflineFrame::V1);
+  auto* v1_frame = frame.mutable_v1();
+  auto* sub_frame = v1_frame->mutable_bandwidth_upgrade_negotiation();
+  sub_frame->set_event_type(
+      BandwidthUpgradeNegotiationFrame::UPGRADE_PATH_AVAILABLE);
+  auto* upgrade_path_info = sub_frame->mutable_upgrade_path_info();
+  upgrade_path_info->set_supports_client_introduction_ack(false);
+
+  bwu_manager_->OnIncomingFrame(frame, std::string(kEndpointId1), &client_,
+                                Medium::BLUETOOTH);
+  CountDownLatch latch(1);
+  bwu_manager_->OnEndpointDisconnect(&client_, (std::string)kServiceIdA,
+                                     std::string(kEndpointId1), latch);
+
+  ASSERT_EQ(fake_wifi_lan_bwu_handler_->handle_revert_calls().size(), 0u);
+}
+
 TEST_F(BwuManagerTest, OnReceiveBwuEvent) {
   // TODO(b/235109434): Add more unit tests coverage for BWU module
 }