Persist advertising endpoint ID.

PiperOrigin-RevId: 820267327

connections/c/nc.cc

@@ -844,3 +844,12 @@ void NcSetPhenotypeFlagReader(READER_CONTEXT context,
       context, phenotype_flag_reader);
   nearby::NearbyFlags::GetInstance().SetFlagReader(*kNearbyFlags);
 }
+
+void NcSaveStates(NC_INSTANCE instance) {
+  NcContext* nc_context = GetContext(instance);
+  if (nc_context == nullptr) {
+    return;
+  }
+
+  nc_context->core->SaveStates();
+}

connections/c/nc.h

@@ -196,6 +196,10 @@ NC_API void NcSetCustomSavePath(NC_INSTANCE instance, const NC_DATA* save_path,
 NC_API void NcSetPhenotypeFlagReader(
     READER_CONTEXT context, NC_PHENOTYPE_FLAG_READER phenotype_flag_reader);
 
+// Saves the states of Nearby Connections to preferences. This is used to
+// restore the states when restart the Nearby Connections.
+NC_API void NcSaveStates(NC_INSTANCE instance);
+
 #ifdef __cplusplus
 }  // extern "C"
 #endif  // __cplusplus

connections/core.cc

@@ -207,6 +207,8 @@ void Core::SetCustomSavePath(absl::string_view path, ResultCallback callback) {
   router_->SetCustomSavePath(&client_, path, std::move(callback));
 }
 
+void Core::SaveStates() { client_.SaveClientInfoToPreferences(); }
+
 std::string Core::Dump() { return client_.Dump(); }
 
 // V3

connections/core.h

@@ -258,6 +258,10 @@ class Core {
   // Gets the local endpoint generated by Nearby Connections.
   std::string GetLocalEndpointId() { return client_.GetLocalEndpointId(); }
 
+  // Saves the states of Nearby Connections to preferences. This is used to
+  // restore the states when restart the Nearby Connections.
+  void SaveStates();
+
   std::string Dump();
 
   //******************************* V3 *******************************

connections/implementation/BUILD

@@ -166,6 +166,7 @@ cc_library(
         "//connections/v3:v3_types",
         "//internal/analytics:event_logger",
         "//internal/base:file_path",
+        "//internal/base:files",
         "//internal/base:masker",
         "//internal/flags:nearby_flags",
         "//internal/interop:authentication_status",

connections/implementation/client_proxy.cc

@@ -31,6 +31,7 @@
 #include "absl/random/random.h"
 #include "absl/strings/escaping.h"
 #include "absl/strings/string_view.h"
+#include "absl/time/time.h"
 #include "absl/types/span.h"
 #include "connections/advertising_options.h"
 #include "connections/connection_options.h"
@@ -53,6 +54,7 @@
 #include "connections/v3/listeners.h"
 #include "internal/analytics/event_logger.h"
 #include "internal/base/file_path.h"
+#include "internal/base/files.h"
 #include "internal/flags/nearby_flags.h"
 #include "internal/interop/device.h"
 #include "internal/platform/byte_array.h"
@@ -63,6 +65,7 @@
 #include "internal/platform/error_code_recorder.h"
 #include "internal/platform/feature_flags.h"
 #include "internal/platform/implementation/platform.h"
+#include "internal/platform/implementation/system_clock.h"
 #include "internal/platform/logging.h"
 #include "internal/platform/mac_address.h"
 #include "internal/platform/mutex_lock.h"
@@ -85,6 +88,13 @@ constexpr char kEndpointIdChars[] = {
 
 constexpr absl::string_view kPreferencesFilePath = "Google/Nearby/Connections";
 
+constexpr absl::string_view kAdvertisingEndpointId =
+    "nc.advertising.endpoint_id";
+
+constexpr absl::string_view kAdvertisingTimestamp = "nc.advertising.timestamp";
+
+constexpr absl::Duration kAdvertisingKeepAliveDuration = absl::Seconds(30);
+
 bool IsFeatureUseStableEndpointIdEnabled() {
   return NearbyFlags::GetInstance().GetBoolFlag(
       connections::config_package_nearby::nearby_connections_feature::
@@ -125,6 +135,9 @@ ClientProxy::ClientProxy(::nearby::analytics::EventLogger* event_logger)
   // Generate a 7 bits dedup value.
   absl::BitGen bitgen;
   dct_dedup_ = absl::Uniform(bitgen, 0, 1 << 7);
+
+  // Load advertising info from preferences.
+  LoadClientInfoFromPreferences();
 }
 
 ClientProxy::~ClientProxy() { Reset(); }
@@ -1360,10 +1373,16 @@ void ClientProxy::InitializePreferencesManager() {
   LOG(INFO) << "ClientProxy [InitializePreferencesManager]: client="
             << GetClientId();
   auto device_info_ = std::make_unique<nearby::DeviceInfoImpl>();
+
+  FilePath preferences_path =
+      device_info_->GetAppDataPath().append(FilePath(kPreferencesFilePath));
+
+  if (!Files::FileExists(preferences_path)) {
+    Files::CreateDirectories(preferences_path);
+  }
+
   preferences_manager_ = api::ImplementationPlatform::CreatePreferencesManager(
-      device_info_->GetAppDataPath()
-          .append(FilePath(kPreferencesFilePath))
-          .ToString());
+      preferences_path.ToString());
 
   if (preferences_manager_ == nullptr) {
     LOG(ERROR) << "ClientProxy [Failed to initialize preferences manager]: "
@@ -1372,6 +1391,61 @@ void ClientProxy::InitializePreferencesManager() {
   }
 }
 
+void ClientProxy::SaveClientInfoToPreferences() {
+  MutexLock lock(&mutex_);
+  if (preferences_manager_ == nullptr) {
+    return;
+  }
+
+  if (advertising_info_.IsEmpty()) {
+    preferences_manager_->Remove(kAdvertisingEndpointId);
+    preferences_manager_->Remove(kAdvertisingTimestamp);
+    return;
+  }
+
+  preferences_manager_->SetString(kAdvertisingEndpointId, local_endpoint_id_);
+  preferences_manager_->SetTime(kAdvertisingTimestamp,
+                                SystemClock::ElapsedRealtime());
+
+  LOG(INFO) << "ClientProxy [SaveClientInfoToPreferences]: client="
+            << GetClientId() << "; local_endpoint_id_=" << local_endpoint_id_;
+}
+
+void ClientProxy::LoadClientInfoFromPreferences() {
+  MutexLock lock(&mutex_);
+  if (preferences_manager_ == nullptr) {
+    return;
+  }
+
+  absl::Time last_advertising_time = preferences_manager_->GetTime(
+      kAdvertisingTimestamp, absl::InfinitePast());
+  if (SystemClock::ElapsedRealtime() - last_advertising_time <
+      kAdvertisingKeepAliveDuration) {
+    std::string endpoint_id =
+        preferences_manager_->GetString(kAdvertisingEndpointId, "");
+    if (!endpoint_id.empty() && endpoint_id.length() == kEndpointIdLength) {
+      bool is_valid_endpoint_id = true;
+      for (const auto& c : endpoint_id) {
+        if (!((c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9'))) {
+          is_valid_endpoint_id = false;
+          break;
+        }
+      }
+
+      if (is_valid_endpoint_id) {
+        local_endpoint_id_ = endpoint_id;
+        cached_endpoint_id_ = local_endpoint_id_;
+        LOG(INFO) << "ClientProxy [LoadClientInfoFromPreferences]: client="
+                  << GetClientId()
+                  << "; local_endpoint_id_=" << local_endpoint_id_;
+      }
+    }
+  }
+
+  preferences_manager_->Remove(kAdvertisingEndpointId);
+  preferences_manager_->Remove(kAdvertisingTimestamp);
+}
+
 std::string ClientProxy::ToString(PayloadProgressInfo::Status status) const {
   switch (status) {
     case PayloadProgressInfo::Status::kSuccess:

connections/implementation/client_proxy.h

@@ -372,6 +372,9 @@ class ClientProxy final {
   // Forces client to regenerate a new local endpoint id.
   void ClearCachedLocalEndpointId();
 
+  // Saves the client information to preferences.
+  void SaveClientInfoToPreferences();
+
  private:
   struct Connection {
     // Status: may be either:
@@ -460,6 +463,7 @@ class ClientProxy final {
   std::optional<std::string> GetEndpointIdForDct() const;
 
   void InitializePreferencesManager();
+  void LoadClientInfoFromPreferences();
 
   // The device name used for DCT advertising.
   std::string dct_device_name_;

connections/implementation/client_proxy_test.cc

@@ -162,7 +162,8 @@ class ClientProxyTest : public ::testing::TestWithParam<FeatureFlags::Flags> {
 
   void SetUp() override {
     EnvironmentConfig config{/*webrtc_enabled=*/false,
-                             /*use_simulated_clock=*/true};
+                             /*use_simulated_clock=*/true,
+                             /*use_temporary_directory_for_app_path=*/true};
     env_.Start(config);
     client1_ = std::make_unique<ClientProxy>(&event_logger1_);
     client2_ = std::make_unique<ClientProxy>(&event_logger2_);
@@ -1621,6 +1622,66 @@ TEST_F(ClientProxyTest, TestRemoteMultiplexSocketBitmask) {
       false);
 }
 
+TEST_F(ClientProxyTest, SaveClientInfoFromPreferences) {
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::kUseStableEndpointId,
+      true);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::
+          kEnableNearbyConnectionsPreferences,
+      true);
+  client1_ = std::make_unique<ClientProxy>(&event_logger1_);
+  Endpoint advertising_endpoint =
+      StartAdvertising(client1(), advertising_connection_listener_);
+  std::string endpoint_id = advertising_endpoint.id;
+  client1_->SaveClientInfoToPreferences();
+
+  // Destroy the client and create a new one.
+  client1_.reset();
+  client1_ = std::make_unique<ClientProxy>(&event_logger1_);
+
+  // The new client should load the same endpoint ID.
+  EXPECT_EQ(client1()->GetLocalEndpointId(), endpoint_id);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::kUseStableEndpointId,
+      false);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::
+          kEnableNearbyConnectionsPreferences,
+      false);
+}
+
+TEST_F(ClientProxyTest, NotLoadClientInfoFromPreferencesOnExpired) {
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::kUseStableEndpointId,
+      true);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::
+          kEnableNearbyConnectionsPreferences,
+      true);
+  client1_ = std::make_unique<ClientProxy>(&event_logger1_);
+  Endpoint advertising_endpoint =
+      StartAdvertising(client1(), advertising_connection_listener_);
+  std::string endpoint_id = advertising_endpoint.id;
+  client1_->SaveClientInfoToPreferences();
+
+  // Destroy the client and create a new one.
+  client1_.reset();
+  FastForward(absl::Hours(25));
+
+  client1_ = std::make_unique<ClientProxy>(&event_logger1_);
+
+  // The new client should load the same endpoint ID.
+  EXPECT_NE(client1()->GetLocalEndpointId(), endpoint_id);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::kUseStableEndpointId,
+      false);
+  NearbyFlags::GetInstance().OverrideBoolFlagValue(
+      config_package_nearby::nearby_connections_feature::
+          kEnableNearbyConnectionsPreferences,
+      false);
+}
+
 }  // namespace
 }  // namespace connections
 }  // namespace nearby

internal/platform/implementation/g3/device_info.h

@@ -26,6 +26,7 @@
 #include "internal/base/files.h"
 #include "internal/platform/implementation/device_info.h"
 #include "internal/platform/implementation/g3/linux_path_util.h"
+#include "internal/platform/medium_environment.h"
 
 namespace nearby {
 namespace g3 {
@@ -49,6 +50,12 @@ class DeviceInfo : public api::DeviceInfo {
   }
 
   std::optional<FilePath> GetLocalAppDataPath() const override {
+    if (MediumEnvironment::Instance()
+            .GetEnvironmentConfig()
+            .use_temporary_directory_for_app_path) {
+      return Files::GetTemporaryDirectory();
+    }
+
     return GetAppDataPath();
   }
 

internal/platform/medium_environment.h

@@ -63,6 +63,10 @@ struct EnvironmentConfig {
   // The simulated clock is automatically picked up by SystemClock, Timer and
   // ScheduledExecutor implementations.
   bool use_simulated_clock = false;
+
+  // If true, the app data path will be a temporary directory, instead of the
+  // actual app data path, so that we can test the preferences manager under G3.
+  bool use_temporary_directory_for_app_path = false;
 };
 
 // MediumEnvironment is a simulated environment which allows multiple instances