Separate LE scanner and GATT client BTIF interfaces (3/3)

In order to properly separate low level structures associated with LE
scanner and GATT client, their interfaces must be separated first.

Test: sl4a BleScanApiTest
Bug: 30622771
Change-Id: If804632c8e4b08fd15d5b847c7838822cf98d79f
diff --git a/service/low_energy_scanner.h b/service/low_energy_scanner.h
new file mode 100644
index 0000000..cae1f58
--- /dev/null
+++ b/service/low_energy_scanner.h
@@ -0,0 +1,160 @@
+//
+//  Copyright (C) 2016 The Android Open Source Project
+//
+//  Licensed under the Apache License, Version 2.0 (the "License");
+//  you may not use this file except in compliance with the License.
+//  You may obtain a copy of the License at:
+//
+//  http://www.apache.org/licenses/LICENSE-2.0
+//
+//  Unless required by applicable law or agreed to in writing, software
+//  distributed under the License is distributed on an "AS IS" BASIS,
+//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+//  See the License for the specific language governing permissions and
+//  limitations under the License.
+//
+
+#pragma once
+
+#include <atomic>
+#include <functional>
+#include <map>
+#include <mutex>
+
+#include <base/macros.h>
+
+#include "service/bluetooth_instance.h"
+#include "service/common/bluetooth/advertise_data.h"
+#include "service/common/bluetooth/advertise_settings.h"
+#include "service/common/bluetooth/low_energy_constants.h"
+#include "service/common/bluetooth/scan_filter.h"
+#include "service/common/bluetooth/scan_result.h"
+#include "service/common/bluetooth/scan_settings.h"
+#include "service/common/bluetooth/uuid.h"
+#include "service/hal/bluetooth_gatt_interface.h"
+
+namespace bluetooth {
+
+class Adapter;
+
+// A LowEnergyScanner represents an application's handle to perform various
+// Bluetooth Low Energy GAP operations. Instances cannot be created directly and
+// should be obtained through the factory.
+class LowEnergyScanner : private hal::BluetoothGattInterface::ScannerObserver,
+                         public BluetoothInstance {
+ public:
+  // The Delegate interface is used to notify asynchronous events related to LE
+  // scan.
+  class Delegate {
+   public:
+    Delegate() = default;
+    virtual ~Delegate() = default;
+
+    // Called asynchronously to notify the delegate of nearby BLE advertisers
+    // found during a device scan.
+    virtual void OnScanResult(LowEnergyScanner* client,
+                              const ScanResult& scan_result) = 0;
+
+   private:
+    DISALLOW_COPY_AND_ASSIGN(Delegate);
+  };
+
+  // The destructor automatically unregisters this client instance from the
+  // stack.
+  ~LowEnergyScanner() override;
+
+  // Assigns a delegate to this instance. |delegate| must out-live this
+  // LowEnergyClient instance.
+  void SetDelegate(Delegate* delegate);
+
+  // Initiates a BLE device scan for this client using the given |settings| and
+  // |filters|. See the documentation for ScanSettings and ScanFilter for how
+  // these parameters can be configured. Return true on success, false
+  // otherwise. Please see logs for details in case of error.
+  bool StartScan(const ScanSettings& settings,
+                 const std::vector<ScanFilter>& filters);
+
+  // Stops an ongoing BLE device scan for this client.
+  bool StopScan();
+
+  // Returns the current scan settings.
+  const ScanSettings& scan_settings() const { return scan_settings_; }
+
+  // BluetoothInstace overrides:
+  const UUID& GetAppIdentifier() const override;
+  int GetInstanceId() const override;
+
+  void ScanResultCallback(
+      hal::BluetoothGattInterface* gatt_iface,
+      const bt_bdaddr_t& bda, int rssi,
+      vector<uint8_t> adv_data) override;
+
+ private:
+  friend class LowEnergyScannerFactory;
+
+  // Constructor shouldn't be called directly as instances are meant to be
+  // obtained from the factory.
+  LowEnergyScanner(Adapter& adapter, const UUID& uuid, int scanner_id);
+
+  // Calls and clears the pending callbacks.
+  void InvokeAndClearStartCallback(BLEStatus status);
+  void InvokeAndClearStopCallback(BLEStatus status);
+
+  // Raw pointer to the Bluetooth Adapter.
+  Adapter& adapter_;
+
+  // See getters above for documentation.
+  UUID app_identifier_;
+  int scanner_id_;
+
+  // Protects device scan related members below.
+  std::mutex scan_fields_lock_;
+
+  // Current scan settings.
+  ScanSettings scan_settings_;
+
+  // If true, then this client have a BLE device scan in progress.
+  std::atomic_bool scan_started_;
+
+  // Raw handle to the Delegate, which must outlive this LowEnergyScanner
+  // instance.
+  std::mutex delegate_mutex_;
+  Delegate* delegate_;
+
+  DISALLOW_COPY_AND_ASSIGN(LowEnergyScanner);
+};
+
+// LowEnergyScannerFactory is used to register and obtain a per-application
+// LowEnergyScanner instance. Users should call RegisterInstance to obtain their
+// own unique LowEnergyScanner instance that has been registered with the
+// Bluetooth stack.
+class LowEnergyScannerFactory
+    : private hal::BluetoothGattInterface::ScannerObserver,
+      public BluetoothInstanceFactory {
+ public:
+  // Don't construct/destruct directly except in tests. Instead, obtain a handle
+  // from an Adapter instance.
+  explicit LowEnergyScannerFactory(Adapter& adapter);
+  ~LowEnergyScannerFactory() override;
+
+  // BluetoothInstanceFactory override:
+  bool RegisterInstance(const UUID& app_uuid, const RegisterCallback& callback) override;
+
+ private:
+  friend class LowEnergyScanner;
+
+  // BluetoothGattInterface::ScannerObserver overrides:
+  void RegisterScannerCallback(hal::BluetoothGattInterface* gatt_iface, int status,
+                               int scanner_id, const bt_uuid_t& app_uuid);
+
+  // Map of pending calls to register.
+  std::mutex pending_calls_lock_;
+  std::map<UUID, RegisterCallback> pending_calls_;
+
+  // Raw pointer to the Adapter that owns this factory.
+  Adapter& adapter_;
+
+  DISALLOW_COPY_AND_ASSIGN(LowEnergyScannerFactory);
+};
+
+}  // namespace bluetooth