fixed device lost callback path for async callbacks in ble. implemented startscanning for fast init manager

.bazelversion

@@ -0,0 +1 @@
+9.0.1

internal/platform/implementation/linux/bluez_advertisement_monitor.cc

@@ -1,7 +1,5 @@
 #include "internal/platform/implementation/linux/bluez_advertisement_monitor.h"
 
-#include <regex>
-
 #include "internal/platform/byte_array.h"
 #include "internal/platform/implementation/ble.h"
 #include "internal/platform/implementation/linux/dbus.h"
@@ -11,7 +9,7 @@ namespace nearby {
 namespace linux {
 namespace bluez {
 AdvertisementMonitor::AdvertisementMonitor(
-    sdbus::IConnection &system_bus, Uuid service_uuid,
+    sdbus::IConnection& system_bus, Uuid service_uuid,
     api::ble::TxPowerLevel tx_power_level, absl::string_view type,
     std::shared_ptr<BluetoothDevices> devices,
     api::ble::BleMedium::ScanCallback scan_callback)
@@ -23,30 +21,38 @@ AdvertisementMonitor::AdvertisementMonitor(
                   std::move(scan_callback.advertisement_found_cb)}) {}
 
 AdvertisementMonitor::AdvertisementMonitor(
-    sdbus::IConnection &system_bus, Uuid service_uuid,
+    sdbus::IConnection& system_bus, Uuid service_uuid,
     api::ble::TxPowerLevel tx_power_level, absl::string_view type,
     std::shared_ptr<BluetoothDevices> devices,
     api::ble::BleMedium::ScanningCallback scan_callback)
-    : AdaptorInterfaces(system_bus, bluez::advertisement_monitor_path(
+    : AdvertisementMonitor(
-                                        std::string{service_uuid})),
+          system_bus,
+          bluez::advertisement_monitor_path(std::string{service_uuid}),
+          service_uuid, tx_power_level, type, std::move(devices),
+          std::move(scan_callback)) {}
+
+AdvertisementMonitor::AdvertisementMonitor(
+    sdbus::IConnection& system_bus, sdbus::ObjectPath object_path,
+    Uuid service_uuid, api::ble::TxPowerLevel tx_power_level,
+    absl::string_view type, std::shared_ptr<BluetoothDevices> devices,
+    api::ble::BleMedium::ScanningCallback scan_callback)
+    : AdaptorInterfaces(system_bus, std::move(object_path)),
       devices_(std::move(devices)),
-      scan_callback_{std::move(scan_callback.advertisement_found_cb)},
+      scan_callback_(std::move(scan_callback)),
-      start_scanning_result_callback_(
-          std::move(scan_callback.start_scanning_result)),
       type_(type),
       service_uuid_(service_uuid),
       tx_power_level_(tx_power_level) {
   registerAdaptor();
 }
 
-void AdvertisementMonitor::DeviceFound(const sdbus::ObjectPath &device) {
+void AdvertisementMonitor::DeviceFound(const sdbus::ObjectPath& device) {
   devices_->cleanup_lost_peripherals();
   auto peripheral = devices_->add_new_device(device);
   auto service_data = peripheral->ServiceData();
   if (!service_data.has_value()) return;
 
   struct api::ble::BleAdvertisementData adv_data;
-  for (const auto &[uuid_str, data] : *service_data) {
+  for (const auto& [uuid_str, data] : *service_data) {
     auto uuid = UuidFromString(uuid_str);
     if (!uuid.has_value()) {
       LOG(ERROR)
@@ -60,12 +66,15 @@ void AdvertisementMonitor::DeviceFound(const sdbus::ObjectPath &device) {
     adv_data.service_data.emplace(*uuid,
                                   std::string(bytes.begin(), bytes.end()));
   }
-  auto id = std::stoull(std::regex_replace(peripheral->GetMacAddress().ToString(),
+  auto id = peripheral->GetMacAddress().address();
-      std::regex("[:\\-]"), ""), nullptr, 16);
   scan_callback_.advertisement_found_cb(id, adv_data);
 }
 
-void AdvertisementMonitor::DeviceLost(const sdbus::ObjectPath &device) {
+void AdvertisementMonitor::DeviceLost(const sdbus::ObjectPath& device) {
+  auto peripheral = devices_->get_device_by_path(device);
+  if (peripheral != nullptr) {
+    scan_callback_.advertisement_lost_cb(peripheral->GetMacAddress().address());
+  }
   devices_->mark_peripheral_lost(device);
 }
 }  // namespace bluez

internal/platform/implementation/linux/bluez_advertisement_monitor.h

@@ -47,16 +47,22 @@ class AdvertisementMonitor final
                        absl::string_view type,
                        std::shared_ptr<BluetoothDevices> devices,
                        api::ble::BleMedium::ScanningCallback scan_callback);
+  AdvertisementMonitor(sdbus::IConnection& system_bus,
+                       sdbus::ObjectPath object_path, Uuid service_uuid,
+                       api::ble::TxPowerLevel tx_power_level,
+                       absl::string_view type,
+                       std::shared_ptr<BluetoothDevices> devices,
+                       api::ble::BleMedium::ScanningCallback scan_callback);
   ~AdvertisementMonitor() { unregisterAdaptor(); }
 
  private:
   // Methods
   void Release() override {}
   void Activate() override {
-    LOG(INFO) <<__func__ << ": bluez advertisement monitor activated at path: "
+    LOG(INFO) << __func__ << ": bluez advertisement monitor activated at path: "
               << getObject().getObjectPath();
-    if (start_scanning_result_callback_ != nullptr) {
+    if (scan_callback_.start_scanning_result != nullptr) {
-      start_scanning_result_callback_(absl::OkStatus());
+      scan_callback_.start_scanning_result(absl::OkStatus());
     }
   }
 
@@ -66,9 +72,7 @@ class AdvertisementMonitor final
   // Properties
   std::string Type() override { return type_; };
   int16_t RSSILowThreshold() override { return 127; };
-  int16_t RSSIHighThreshold() override {
+  int16_t RSSIHighThreshold() override { return 127; }
-    return 127;
-  }
   uint16_t RSSISamplingPeriod() override {
     // The Windows implementation uses a sampling interval of 2 seconds.
     return 20;
@@ -79,13 +83,11 @@ class AdvertisementMonitor final
     return {{0,
              0x16,
              {static_cast<uint8_t>(service_id_data[3] & 0xFF),
-              static_cast<uint8_t>(service_id_data[2] & 0xFF)}
+              static_cast<uint8_t>(service_id_data[2] & 0xFF)}}};
-    }};
   };
 
   std::shared_ptr<BluetoothDevices> devices_;
-  api::ble::BleMedium::ScanCallback scan_callback_;
+  api::ble::BleMedium::ScanningCallback scan_callback_;
-  absl::AnyInvocable<void(absl::Status)> start_scanning_result_callback_;
 
   std::string type_;
   Uuid service_uuid_;

sharing/linux/BUILD

@@ -61,6 +61,19 @@ cc_binary(
     deps = [":fast_init"],
 )
 
+cc_test(
+    name = "nearby_fast_init_manager_test",
+    size = "small",
+    srcs = ["nearby_fast_init_manager_test.cc"],
+    deps = [
+        ":fast_init",
+        "//internal/platform:base",
+        "//internal/platform/implementation:types",
+        "//internal/platform/implementation/linux",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 
 cc_binary(
     name = "nearby_sharing_cli",

sharing/linux/nearby_fast_init_manager.cc

@@ -1,17 +1,64 @@
+#include <algorithm>
 #include <functional>
+#include <map>
+#include <optional>
+#include <string>
+#include <utility>
+#include <vector>
 
+#include "absl/synchronization/mutex.h"
+#include "absl/synchronization/notification.h"
+#include "internal/platform/implementation/ble.h"
 #include "sharing/internal/api/fast_init_ble_beacon.h"
 #include "sharing/internal/api/fast_initiation_manager.h"
 
 #include "internal/platform/implementation/linux/bluetooth_adapter.h"
-#include "sharing/linux/nearby_fast_init_manager.h"
+#include "internal/platform/implementation/linux/bluetooth_devices.h"
 #include "internal/platform/implementation/linux/bluez.h"
+#include "internal/platform/implementation/linux/bluez_advertisement_monitor.h"
+#include "internal/platform/implementation/linux/bluez_advertisement_monitor_manager.h"
 #include "internal/platform/implementation/linux/bluez_le_advertisement.h"
+#include "internal/platform/implementation/linux/dbus.h"
+#include "internal/platform/uuid.h"
+#include "sharing/linux/nearby_fast_init_manager.h"
 
 namespace nearby {
 namespace sharing {
 namespace linux {
 
+namespace {
+
+constexpr char kFastInitMonitorRootPath[] =
+    "/com/google/nearby/sharing/fast_init/monitor";
+constexpr char kFastInitMonitorPath[] =
+    "/com/google/nearby/sharing/fast_init/monitor/fe2c";
+constexpr size_t kFastInitServiceDataSize =
+    nearby::api::FastInitBleBeacon::kAdvertiseDataTotalSize -
+    nearby::api::FastInitBleBeacon::kFastInitServiceUuidSize;
+
+nearby::api::FastInitiationManager::Error MapBluezError(
+    const std::string& error_name) {
+  if (error_name == "org.bluez.Error.AlreadyExists" ||
+      error_name == "org.bluez.Error.InProgress") {
+    return nearby::api::FastInitiationManager::Error::kResourceInUse;
+  }
+  if (error_name == "org.bluez.Error.NotPermitted" ||
+      error_name == "org.bluez.Error.NotAuthorized") {
+    return nearby::api::FastInitiationManager::Error::kDisabledByUser;
+  }
+  if (error_name == "org.bluez.Error.NotSupported") {
+    return nearby::api::FastInitiationManager::Error::kHardwareNotSupported;
+  }
+  return nearby::api::FastInitiationManager::Error::kUnknown;
+}
+
+}  // namespace
+
+LinuxFastInitiationManager::~LinuxFastInitiationManager() {
+  StopScanning(nullptr);
+  StopAdvertising(nullptr);
+}
+
 void LinuxFastInitiationManager::StartAdvertising(
     nearby::api::FastInitBleBeacon::FastInitType type,
     std::function<void()> callback,
@@ -121,22 +168,301 @@ void LinuxFastInitiationManager::StopAdvertising(
     callback();
   }
 }
-void StopScanning(std::function<void()> callback) {
-  if (callback) {
-    callback();
-  }
-}
 void LinuxFastInitiationManager::StartScanning(
     std::function<void()> devices_discovered_callback,
     std::function<void()> devices_not_discovered_callback,
     std::function<void(nearby::api::FastInitiationManager::Error)>
         error_callback) {
-  if (error_callback) {
+  std::optional<nearby::api::FastInitiationManager::Error> error;
-    error_callback(
+  {
-        nearby::api::FastInitiationManager::Error::kHardwareNotSupported);
+    absl::MutexLock operation_lock(&scan_operation_mutex_);
+    error = StartScanningInternal(std::move(devices_discovered_callback),
+                                  std::move(devices_not_discovered_callback));
   }
+  if (error.has_value() && error_callback) {
+    error_callback(*error);
+  }
+}
+
+std::optional<nearby::api::FastInitiationManager::Error>
+LinuxFastInitiationManager::StartScanningInternal(
+    std::function<void()> devices_discovered_callback,
+    std::function<void()> devices_not_discovered_callback) {
+  bool already_scanning = false;
+  {
+    absl::MutexLock lock(&mutex_);
+    already_scanning = is_scanning_;
+  }
+  if (already_scanning) {
+    return nearby::api::FastInitiationManager::Error::kResourceInUse;
+  }
+
+  if (adapter_ == nullptr || !adapter_->IsEnabled()) {
+    return nearby::api::FastInitiationManager::Error::
+        kBluetoothRadioUnavailable;
+  }
+
+  auto fast_init_uuid = Uuid::FromString(kFastInitServiceUuid);
+  if (!fast_init_uuid.has_value()) {
+    return nearby::api::FastInitiationManager::Error::kUnknown;
+  }
+
+  auto connection = adapter_->GetConnection();
+  auto monitor_manager = ::nearby::linux::bluez::AdvertisementMonitorManager::
+      DiscoverAdvertisementMonitorManager(*connection, *adapter_);
+  if (monitor_manager == nullptr) {
+    return nearby::api::FastInitiationManager::Error::kHardwareNotSupported;
+  }
+
+  try {
+    const std::vector<std::string> supported_types =
+        monitor_manager->SupportedMonitorTypes();
+    if (std::find(supported_types.begin(), supported_types.end(),
+                  "or_patterns") == supported_types.end()) {
+      return nearby::api::FastInitiationManager::Error::kHardwareNotSupported;
+    }
+  } catch (const sdbus::Error& error) {
+    return MapBluezError(error.getName());
+  }
+
+  uint64_t generation;
+  try {
+    {
+      absl::MutexLock lock(&mutex_);
+      is_scanning_ = true;
+      generation = ++scan_generation_;
+      devices_discovered_callback_ = std::move(devices_discovered_callback);
+      devices_not_discovered_callback_ =
+          std::move(devices_not_discovered_callback);
+      discovered_peripherals_.clear();
+    }
+    scan_devices_ = ::nearby::linux::GetSharedBluetoothDevices(
+        connection, adapter_->GetObjectPath());
+    scan_root_object_manager_ =
+        std::make_unique<::nearby::linux::RootObjectManager>(
+            *connection, sdbus::ObjectPath(kFastInitMonitorRootPath));
+    scan_monitor_ =
+        std::make_unique<::nearby::linux::bluez::AdvertisementMonitor>(
+            *connection, sdbus::ObjectPath(kFastInitMonitorPath),
+            *fast_init_uuid, nearby::api::ble::TxPowerLevel::kLow,
+            "or_patterns", scan_devices_,
+            nearby::api::ble::BleMedium::ScanningCallback{
+                .advertisement_found_cb =
+                    [this, generation](
+                        nearby::api::ble::BlePeripheral::UniqueId peripheral_id,
+                        nearby::api::ble::BleAdvertisementData data) {
+                      OnAdvertisementFound(generation, peripheral_id,
+                                           std::move(data));
+                    },
+                .advertisement_lost_cb =
+                    [this,
+                     generation](nearby::api::ble::BlePeripheral::UniqueId id) {
+                      OnAdvertisementLost(generation, id);
+                    },
+            });
+    scan_monitor_manager_ = std::move(monitor_manager);
+  } catch (const sdbus::Error& error) {
+    {
+      absl::MutexLock lock(&mutex_);
+      is_scanning_ = false;
+      devices_discovered_callback_ = nullptr;
+      devices_not_discovered_callback_ = nullptr;
+    }
+    scan_monitor_.reset();
+    scan_root_object_manager_.reset();
+    scan_devices_.reset();
+    return MapBluezError(error.getName());
+  }
+
+  absl::Notification registration_complete;
+  std::string registration_error_name;
+  scan_monitor_manager_->SetRegisterMonitorReplyCallback(
+      [&registration_complete,
+       &registration_error_name](std::optional<sdbus::Error> error) {
+        if (error.has_value() && error->isValid()) {
+          registration_error_name = error->getName();
+        }
+        registration_complete.Notify();
+      });
+  try {
+    scan_monitor_manager_->RegisterMonitor(
+        scan_root_object_manager_->getObject().getObjectPath());
+    registration_complete.WaitForNotification();
+  } catch (const sdbus::Error& error) {
+    registration_error_name = error.getName();
+  }
+
+  if (!registration_error_name.empty()) {
+    {
+      absl::MutexLock lock(&mutex_);
+      is_scanning_ = false;
+      ++scan_generation_;
+      devices_discovered_callback_ = nullptr;
+      devices_not_discovered_callback_ = nullptr;
+      discovered_peripherals_.clear();
+    }
+    scan_monitor_.reset();
+    scan_root_object_manager_.reset();
+    scan_monitor_manager_.reset();
+    scan_devices_.reset();
+    return MapBluezError(registration_error_name);
+  }
+
+  try {
+    auto& bluez_adapter = adapter_->GetBluezAdapterObject();
+    if (!bluez_adapter.Discovering()) {
+      std::map<std::string, sdbus::Variant> filter;
+      filter["Transport"] = sdbus::Variant("le");
+      filter["DuplicateData"] = sdbus::Variant(true);
+      bluez_adapter.SetDiscoveryFilter(filter);
+      bluez_adapter.StartDiscovery();
+      absl::MutexLock lock(&mutex_);
+      owns_bluez_discovery_ = true;
+    }
+  } catch (const sdbus::Error& error) {
+    // Release the scan application before reporting a failed start.
+    StopScanningInternal();
+    return MapBluezError(error.getName());
+  }
+  return std::nullopt;
+}
+
+void LinuxFastInitiationManager::StopScanning(std::function<void()> callback) {
+  {
+    absl::MutexLock operation_lock(&scan_operation_mutex_);
+    StopScanningInternal();
+  }
+  if (callback) {
+    callback();
+  }
+}
+
+void LinuxFastInitiationManager::StopScanningInternal() {
+  bool owns_discovery = false;
+  {
+    absl::MutexLock lock(&mutex_);
+    if (!is_scanning_) {
+      return;
+    }
+    is_scanning_ = false;
+    owns_discovery = owns_bluez_discovery_;
+    owns_bluez_discovery_ = false;
+    ++scan_generation_;
+    devices_discovered_callback_ = nullptr;
+    devices_not_discovered_callback_ = nullptr;
+    discovered_peripherals_.clear();
+  }
+
+  if (owns_discovery && adapter_ != nullptr) {
+    try {
+      adapter_->GetBluezAdapterObject().StopDiscovery();
+    } catch (const sdbus::Error& error) {
+      DBUS_LOG_METHOD_CALL_ERROR(&adapter_->GetBluezAdapterObject(),
+                                 "StopDiscovery", error);
+    }
+  }
+
+  if (scan_monitor_manager_ != nullptr &&
+      scan_root_object_manager_ != nullptr) {
+    absl::Notification unregistration_complete;
+    scan_monitor_manager_->SetUnregisterMonitorReplyCallback(
+        [&unregistration_complete](std::optional<sdbus::Error>) {
+          unregistration_complete.Notify();
+        });
+    try {
+      scan_monitor_manager_->UnregisterMonitor(
+          scan_root_object_manager_->getObject().getObjectPath());
+      unregistration_complete.WaitForNotification();
+    } catch (const sdbus::Error& error) {
+      DBUS_LOG_METHOD_CALL_ERROR(scan_monitor_manager_.get(),
+                                 "UnregisterMonitor", error);
+    }
+  }
+
+  scan_monitor_.reset();
+  scan_root_object_manager_.reset();
+  scan_monitor_manager_.reset();
+  scan_devices_.reset();
+}
+
+bool LinuxFastInitiationManager::IsScanning() {
+  absl::MutexLock lock(&mutex_);
+  return is_scanning_;
+}
+
+void LinuxFastInitiationManager::OnAdvertisementFound(
+    uint64_t scan_generation,
+    nearby::api::ble::BlePeripheral::UniqueId peripheral_id,
+    nearby::api::ble::BleAdvertisementData advertisement_data) {
+  if (!IsFastInitAdvertisement(advertisement_data)) {
+    return;
+  }
+
+  std::function<void()> callback;
+  {
+    absl::MutexLock lock(&mutex_);
+    if (!is_scanning_ || scan_generation != scan_generation_) {
+      return;
+    }
+    auto [unused, inserted] = discovered_peripherals_.insert(peripheral_id);
+    if (inserted && discovered_peripherals_.size() == 1) {
+      callback = devices_discovered_callback_;
+    }
+  }
+  if (callback) {
+    callback();
+  }
+}
+
+void LinuxFastInitiationManager::OnAdvertisementLost(
+    uint64_t scan_generation,
+    nearby::api::ble::BlePeripheral::UniqueId peripheral_id) {
+  std::function<void()> callback;
+  {
+    absl::MutexLock lock(&mutex_);
+    if (!is_scanning_ || scan_generation != scan_generation_ ||
+        discovered_peripherals_.erase(peripheral_id) == 0) {
+      return;
+    }
+    if (discovered_peripherals_.empty()) {
+      callback = devices_not_discovered_callback_;
+    }
+  }
+  if (callback) {
+    callback();
+  }
+}
+
+bool LinuxFastInitiationManager::IsFastInitAdvertisement(
+    const nearby::api::ble::BleAdvertisementData& advertisement_data) const {
+  auto fast_init_uuid = Uuid::FromString(kFastInitServiceUuid);
+  if (!fast_init_uuid.has_value()) {
+    return false;
+  }
+  auto service_data = advertisement_data.service_data.find(*fast_init_uuid);
+  if (service_data == advertisement_data.service_data.end() ||
+      service_data->second.size() != kFastInitServiceDataSize) {
+    return false;
+  }
+
+  const auto bytes = service_data->second.AsStringView();
+  for (size_t i = 0; i < nearby::api::FastInitBleBeacon::kFastInitModelIdSize;
+       ++i) {
+    if (static_cast<uint8_t>(bytes[i]) !=
+        nearby::api::FastInitBleBeacon::kFastInitModelId[i]) {
+      return false;
+    }
+  }
+
+  const uint8_t metadata = static_cast<uint8_t>(
+      bytes[nearby::api::FastInitBleBeacon::kFastInitModelIdSize]);
+  const uint8_t version = (metadata >> 5) & 0x07;
+  const uint8_t type = (metadata >> 2) & 0x07;
+  return version == static_cast<uint8_t>(
+                        nearby::api::FastInitBleBeacon::FastInitVersion::kV1) &&
+         type <= static_cast<uint8_t>(
+                     nearby::api::FastInitBleBeacon::FastInitType::kSilent);
 }
 }  // namespace linux
 }  // namespace sharing
 }  // namespace nearby
-

sharing/linux/nearby_fast_init_manager.h

@@ -16,13 +16,22 @@
 #ifndef LINUX_NEARBY_SHARING_INTERNAL_API_FAST_INITIATION_MANAGER_H_
 #define LINUX_NEARBY_SHARING_INTERNAL_API_FAST_INITIATION_MANAGER_H_
 
+#include <cstdint>
 #include <functional>
+#include <memory>
+#include <optional>
 
+#include "absl/container/flat_hash_set.h"
+#include "absl/synchronization/mutex.h"
+#include "internal/platform/implementation/ble.h"
 #include "sharing/internal/api/fast_init_ble_beacon.h"
 #include "sharing/internal/api/fast_initiation_manager.h"
 
 #include "internal/platform/implementation/linux/bluetooth_adapter.h"
+#include "internal/platform/implementation/linux/bluetooth_devices.h"
 #include "internal/platform/implementation/linux/bluez.h"
+#include "internal/platform/implementation/linux/bluez_advertisement_monitor.h"
+#include "internal/platform/implementation/linux/bluez_advertisement_monitor_manager.h"
 #include "internal/platform/implementation/linux/bluez_le_advertisement.h"
 
 constexpr char kFastInitServiceUuid[] = "0000fe2c-0000-1000-8000-00805f9b34fb";
@@ -36,7 +45,7 @@ class LinuxFastInitiationManager final
  public:
   explicit LinuxFastInitiationManager(
       nearby::api::FastInitBleBeacon& beacon,
-      std::shared_ptr<::nearby::linux::BluetoothAdapter>  bluetooth_adapter)
+      std::shared_ptr<::nearby::linux::BluetoothAdapter> bluetooth_adapter)
       : beacon_(beacon), adapter_(std::move(bluetooth_adapter)) {
     if (adapter_ != nullptr) {
       adv_manager_ =
@@ -44,12 +53,13 @@ class LinuxFastInitiationManager final
               *adapter_->GetConnection(), *adapter_);
     }
   }
+  ~LinuxFastInitiationManager() override;
 
   void StartAdvertising(
       nearby::api::FastInitBleBeacon::FastInitType type,
       std::function<void()> callback,
       std::function<void(nearby::api::FastInitiationManager::Error)>
-          error_callback) override ;
+          error_callback) override;
 
   void StopAdvertising(std::function<void()> callback) override;
 
@@ -57,27 +67,61 @@ class LinuxFastInitiationManager final
       std::function<void()> devices_discovered_callback,
       std::function<void()> devices_not_discovered_callback,
       std::function<void(nearby::api::FastInitiationManager::Error)>
-          error_callback) override ;
+          error_callback) override;
 
-  void StopScanning(std::function<void()> callback) override {
+  void StopScanning(std::function<void()> callback) override;
-    if (callback) {
-      callback();
-    }
-  }
 
   bool IsAdvertising() override {
     absl::MutexLock lock(&mutex_);
     return advertisement_ != nullptr;
   }
-  bool IsScanning() override { return false; }
+  bool IsScanning() override;
 
  private:
+  friend class LinuxFastInitiationManagerTestPeer;
+
+  void OnAdvertisementFound(
+      uint64_t scan_generation,
+      ::nearby::api::ble::BlePeripheral::UniqueId peripheral_id,
+      ::nearby::api::ble::BleAdvertisementData advertisement_data);
+  void OnAdvertisementLost(
+      uint64_t scan_generation,
+      ::nearby::api::ble::BlePeripheral::UniqueId peripheral_id);
+  bool IsFastInitAdvertisement(
+      const ::nearby::api::ble::BleAdvertisementData& advertisement_data) const;
+  std::optional<nearby::api::FastInitiationManager::Error>
+  StartScanningInternal(std::function<void()> devices_discovered_callback,
+                        std::function<void()> devices_not_discovered_callback)
+      ABSL_EXCLUSIVE_LOCKS_REQUIRED(scan_operation_mutex_);
+  void StopScanningInternal()
+      ABSL_EXCLUSIVE_LOCKS_REQUIRED(scan_operation_mutex_);
+
   nearby::api::FastInitBleBeacon& beacon_;
   std::shared_ptr<::nearby::linux::BluetoothAdapter> adapter_;
   std::unique_ptr<::nearby::linux::bluez::LEAdvertisementManager> adv_manager_;
+  absl::Mutex scan_operation_mutex_;
   absl::Mutex mutex_;
   std::unique_ptr<::nearby::linux::bluez::LEAdvertisement> advertisement_
       ABSL_GUARDED_BY(mutex_);
+
+  bool is_scanning_ ABSL_GUARDED_BY(mutex_) = false;
+  bool owns_bluez_discovery_ ABSL_GUARDED_BY(mutex_) = false;
+  // Incremented for every start/stop so delayed BlueZ callbacks from an old
+  // scan cannot update the device set or notify callbacks for a newer scan.
+  uint64_t scan_generation_ ABSL_GUARDED_BY(mutex_) = 0;
+  std::function<void()> devices_discovered_callback_ ABSL_GUARDED_BY(mutex_);
+  std::function<void()> devices_not_discovered_callback_
+      ABSL_GUARDED_BY(mutex_);
+  absl::flat_hash_set<::nearby::api::ble::BlePeripheral::UniqueId>
+      discovered_peripherals_ ABSL_GUARDED_BY(mutex_);
+  std::shared_ptr<::nearby::linux::BluetoothDevices> scan_devices_
+      ABSL_GUARDED_BY(scan_operation_mutex_);
+  std::unique_ptr<::nearby::linux::RootObjectManager> scan_root_object_manager_
+      ABSL_GUARDED_BY(scan_operation_mutex_);
+  std::unique_ptr<::nearby::linux::bluez::AdvertisementMonitorManager>
+      scan_monitor_manager_ ABSL_GUARDED_BY(scan_operation_mutex_);
+  std::unique_ptr<::nearby::linux::bluez::AdvertisementMonitor> scan_monitor_
+      ABSL_GUARDED_BY(scan_operation_mutex_);
 };
 
 }  // namespace linux

sharing/linux/nearby_fast_init_manager_test.cc

@@ -0,0 +1,116 @@
+#include "sharing/linux/nearby_fast_init_manager.h"
+
+#include <cstdint>
+#include <functional>
+#include <string>
+#include <utility>
+
+#include "absl/synchronization/mutex.h"
+#include "gtest/gtest.h"
+#include "internal/platform/byte_array.h"
+#include "internal/platform/implementation/ble.h"
+#include "internal/platform/uuid.h"
+#include "sharing/linux/nearby_fast_init_ble_beacon.h"
+
+namespace nearby::sharing::linux {
+
+class LinuxFastInitiationManagerTestPeer {
+ public:
+  static void BeginScan(LinuxFastInitiationManager& manager,
+                        std::function<void()> discovered,
+                        std::function<void()> not_discovered) {
+    absl::MutexLock lock(&manager.mutex_);
+    manager.is_scanning_ = true;
+    manager.scan_generation_ = 1;
+    manager.devices_discovered_callback_ = std::move(discovered);
+    manager.devices_not_discovered_callback_ = std::move(not_discovered);
+    manager.discovered_peripherals_.clear();
+  }
+
+  static void Found(LinuxFastInitiationManager& manager, uint64_t id,
+                    api::ble::BleAdvertisementData data) {
+    manager.OnAdvertisementFound(1, id, std::move(data));
+  }
+
+  static void Lost(LinuxFastInitiationManager& manager, uint64_t id) {
+    manager.OnAdvertisementLost(1, id);
+  }
+
+  static bool IsValid(LinuxFastInitiationManager& manager,
+                      const api::ble::BleAdvertisementData& data) {
+    return manager.IsFastInitAdvertisement(data);
+  }
+};
+
+namespace {
+
+api::ble::BleAdvertisementData FastInitAdvertisement(
+    api::FastInitBleBeacon::FastInitType type =
+        api::FastInitBleBeacon::FastInitType::kNotify) {
+  std::string bytes(api::FastInitBleBeacon::kAdvertiseDataTotalSize -
+                        api::FastInitBleBeacon::kFastInitServiceUuidSize,
+                    '\0');
+  for (size_t i = 0; i < api::FastInitBleBeacon::kFastInitModelIdSize; ++i) {
+    bytes[i] = static_cast<char>(api::FastInitBleBeacon::kFastInitModelId[i]);
+  }
+  bytes[api::FastInitBleBeacon::kFastInitModelIdSize] =
+      static_cast<char>(static_cast<uint8_t>(type) << 2);
+
+  api::ble::BleAdvertisementData data;
+  data.service_data.emplace(*Uuid::FromString(kFastInitServiceUuid),
+                            ByteArray(bytes));
+  return data;
+}
+
+TEST(LinuxFastInitiationManagerTest, ValidatesFastInitServiceData) {
+  LinuxFastInitBleBeacon beacon;
+  LinuxFastInitiationManager manager(beacon, nullptr);
+
+  EXPECT_TRUE(LinuxFastInitiationManagerTestPeer::IsValid(
+      manager, FastInitAdvertisement()));
+  EXPECT_TRUE(LinuxFastInitiationManagerTestPeer::IsValid(
+      manager,
+      FastInitAdvertisement(api::FastInitBleBeacon::FastInitType::kSilent)));
+
+  auto malformed = FastInitAdvertisement();
+  malformed.service_data.begin()->second.data()[0] = '\0';
+  EXPECT_FALSE(LinuxFastInitiationManagerTestPeer::IsValid(manager, malformed));
+}
+
+TEST(LinuxFastInitiationManagerTest, ReportsOnlyPresenceTransitions) {
+  LinuxFastInitBleBeacon beacon;
+  LinuxFastInitiationManager manager(beacon, nullptr);
+  int discovered_count = 0;
+  int not_discovered_count = 0;
+  LinuxFastInitiationManagerTestPeer::BeginScan(
+      manager, [&] { ++discovered_count; }, [&] { ++not_discovered_count; });
+
+  LinuxFastInitiationManagerTestPeer::Found(manager, 1,
+                                            FastInitAdvertisement());
+  LinuxFastInitiationManagerTestPeer::Found(manager, 1,
+                                            FastInitAdvertisement());
+  LinuxFastInitiationManagerTestPeer::Found(manager, 2,
+                                            FastInitAdvertisement());
+  EXPECT_EQ(discovered_count, 1);
+
+  LinuxFastInitiationManagerTestPeer::Lost(manager, 99);
+  LinuxFastInitiationManagerTestPeer::Lost(manager, 1);
+  EXPECT_EQ(not_discovered_count, 0);
+  LinuxFastInitiationManagerTestPeer::Lost(manager, 2);
+  EXPECT_EQ(not_discovered_count, 1);
+}
+
+TEST(LinuxFastInitiationManagerTest, StopScanningClearsLogicalState) {
+  LinuxFastInitBleBeacon beacon;
+  LinuxFastInitiationManager manager(beacon, nullptr);
+  LinuxFastInitiationManagerTestPeer::BeginScan(manager, [] {}, [] {});
+  bool stopped = false;
+
+  manager.StopScanning([&] { stopped = true; });
+
+  EXPECT_TRUE(stopped);
+  EXPECT_FALSE(manager.IsScanning());
+}
+
+}  // namespace
+}  // namespace nearby::sharing::linux