service/gatt_server.h - platform/system/bt - Gitiles

 //
 //  Copyright 2015 Google, Inc.
 //
 //  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 <deque>
 #include <functional>
 #include <mutex>
 #include <string>
 #include <unordered_map>
 #include <unordered_set>
 #include <vector>

 #include <base/macros.h>
 #include <bluetooth/uuid.h>

 #include "service/bluetooth_instance.h"
 #include "service/common/bluetooth/service.h"
 #include "service/hal/bluetooth_gatt_interface.h"

 namespace bluetooth {

 // A GattServer instance represents an application's handle to perform GATT
 // server-role operations. Instances cannot be created directly and should be
 // obtained through the factory.
 class GattServer : public BluetoothInstance,
                    private hal::BluetoothGattInterface::ServerObserver {
  public:
   // Delegate interface is used to handle incoming requests and confirmations
   // for a GATT service.
   class Delegate {
    public:
     Delegate() = default;
     virtual ~Delegate() = default;

     // Called when there is an incoming read request for the characteristic with
     // ID |characteristic_id| from a remote device with address
     // |device_address|. |request_id| can be used to respond to this request by
     // calling SendResponse below.
     virtual void OnCharacteristicReadRequest(GattServer* gatt_server,
                                              const std::string& device_address,
                                              int request_id, int offset,
                                              bool is_long, uint16_t handle) = 0;

     // Called when there is an incoming read request for the descriptor with
     // ID |descriptor_id| from a remote device with address |device_address|.
     // |request_id| can be used to respond to this request by
     // calling SendResponse below.
     virtual void OnDescriptorReadRequest(GattServer* gatt_server,
                                          const std::string& device_address,
                                          int request_id, int offset,
                                          bool is_long, uint16_t handle) = 0;

     // Called when there is an incoming write request for the characteristic
     // with ID |characteristic_id| from a remote device with address
     // |device_address|. |request_id| can be used to respond to this request by
     // calling SendResponse, if the |need_response| parameter is true. Otherwise
     // this is a "Write Without Reponse" procedure and SendResponse will fail.
     // If |is_prepare_write| is true, then the write should not be committed
     // immediately as this is a "Prepared Write Request". Instead, the Delegate
     // should hold on to the value and either discard it or complete the write
     // when it receives the OnExecuteWriteRequest event.
     virtual void OnCharacteristicWriteRequest(
         GattServer* gatt_server, const std::string& device_address,
         int request_id, int offset, bool is_prepare_write, bool need_response,
         const std::vector<uint8_t>& value, uint16_t handle) = 0;

     // Called when there is an incoming write request for the descriptor
     // with ID |descriptor_id| from a remote device with address
     // |device_address|. |request_id| can be used to respond to this request by
     // calling SendResponse, if the |need_response| parameter is true. Otherwise
     // this is a "Write Without Response" procedure and SendResponse will fail.
     // If |is_prepare_write| is true, then the write should not be committed
     // immediately as this is a "Prepared Write Request". Instead, the Delegate
     // should hold on to the value and either discard it or complete the write
     // when it receives the OnExecuteWriteRequest event.
     virtual void OnDescriptorWriteRequest(
         GattServer* gatt_server, const std::string& device_address,
         int request_id, int offset, bool is_prepare_write, bool need_response,
         const std::vector<uint8_t>& value, uint16_t handle) = 0;

     // Called when there is an incoming "Execute Write Request". If |is_execute|
     // is true, then the Delegate should commit all previously prepared writes.
     // Otherwise, all prepared writes should be aborted. The Delegate should
     // call "SendResponse" to complete the procedure.
     virtual void OnExecuteWriteRequest(GattServer* gatt_server,
                                        const std::string& device_address,
                                        int request_id, bool is_execute) = 0;

     virtual void OnConnectionStateChanged(GattServer* gatt_server,
                                           const std::string& device_addres,
                                           bool connected) = 0;

    private:
     DISALLOW_COPY_AND_ASSIGN(Delegate);
   };

   // The desctructor automatically unregisters this instance from the stack.
   ~GattServer() override;

   // Assigns a delegate to this instance. |delegate| must out-live this
   // GattServer instance.
   void SetDelegate(Delegate* delegate);

   // BluetoothClientInstace overrides:
   const Uuid& GetAppIdentifier() const override;
   int GetInstanceId() const override;

   // Callback type used to report the status of an asynchronous GATT server
   // operation.
   using ResultCallback =
       std::function<void(BLEStatus status, const Service& id)>;
   using GattCallback = std::function<void(GATTError error)>;

   // Add service declaration. This method immediately
   // returns false if a service hasn't been started. Otherwise, |callback| will
   // be called asynchronously with the result of the operation.
   //
   // TODO(armansito): It is unclear to me what it means for this function to
   // fail. What is the state that we're in? Is the service declaration over so
   // we can add other services to this server instance? Do we need to clean up
   // all the entries or does the upper-layer need to remove the service? Or are
   // we in a stuck-state where the service declaration hasn't ended?
   bool AddService(const Service&, const ResultCallback& callback);

   // Sends a response for a pending notification. |request_id| and
   // |device_address| should match those that were received through one of the
   // Delegate callbacks. |value| and |offset| are used for read requests and
   // prepare write requests and should match the value of the attribute. Returns
   // false if the pending request could not be resolved using the given
   // parameters or if the call to the underlying stack fails.
   bool SendResponse(const std::string& device_address, int request_id,
                     GATTError error, int offset,
                     const std::vector<uint8_t>& value);

   // Sends an ATT Handle-Value Notification to the device with BD_ADDR
   // |device_address| for the characteristic with handle |handle| and
   // value |value|. If |confirm| is true, then an ATT Handle-Value Indication
   // will be sent instead, which requires the remote to confirm receipt. Returns
   // false if there was an immediate error in initiating the notification
   // procedure. Otherwise, returns true and reports the asynchronous result of
   // the operation in |callback|.
   //
   // If |confirm| is true, then |callback| will be run when the remote device
   // sends a ATT Handle-Value Confirmation packet. Otherwise, it will be run as
   // soon as the notification has been sent out.
   bool SendNotification(const std::string& device_address,
                         const uint16_t handle, bool confirm,
                         const std::vector<uint8_t>& value,
                         const GattCallback& callback);

  private:
   friend class GattServerFactory;

   // Used for the internal remote connection tracking. Keeps track of the
   // request ID and the device address for the connection. If |request_id| is -1
   // then no ATT read/write request is currently pending.
   struct Connection {
     Connection(int conn_id, const RawAddress& bdaddr)
         : conn_id(conn_id), bdaddr(bdaddr) {}
     Connection() : conn_id(-1) { memset(&bdaddr, 0, sizeof(bdaddr)); }

     int conn_id;
     std::unordered_map<int, int> request_id_to_handle;
     RawAddress bdaddr;
   };

   // Used to keep track of a pending Handle-Value indication.
   struct PendingIndication {
     explicit PendingIndication(const GattCallback& callback)
         : has_success(false), callback(callback) {}

     bool has_success;
     GattCallback callback;
   };

   // Constructor shouldn't be called directly as instances are meant to be
   // obtained from the factory.
   GattServer(const Uuid& uuid, int server_id);

   // hal::BluetoothGattInterface::ServerObserver overrides:
   void ConnectionCallback(hal::BluetoothGattInterface* gatt_iface, int conn_id,
                           int server_id, int connected,
                           const RawAddress& bda) override;
   void ServiceAddedCallback(hal::BluetoothGattInterface* gatt_iface, int status,
                             int server_if,
                             std::vector<btgatt_db_element_t>) override;
   void ServiceStoppedCallback(hal::BluetoothGattInterface* gatt_iface,
                               int status, int server_id,
                               int service_handle) override;
   void RequestReadCharacteristicCallback(
       hal::BluetoothGattInterface* gatt_iface, int conn_id, int trans_id,
       const RawAddress& bda, int attribute_handle, int offset,
       bool is_long) override;
   void RequestReadDescriptorCallback(hal::BluetoothGattInterface* gatt_iface,
                                      int conn_id, int trans_id,
                                      const RawAddress& bda,
                                      int attribute_handle, int offset,
                                      bool is_long) override;
   void RequestWriteCharacteristicCallback(
       hal::BluetoothGattInterface* gatt_iface, int conn_id, int trans_id,
       const RawAddress& bda, int attr_handle, int offset, bool need_rsp,
       bool is_prep, std::vector<uint8_t> value) override;
   void RequestWriteDescriptorCallback(hal::BluetoothGattInterface* gatt_iface,
                                       int conn_id, int trans_id,
                                       const RawAddress& bda, int attr_handle,
                                       int offset, bool need_rsp, bool is_prep,
                                       std::vector<uint8_t> value) override;
   void RequestExecWriteCallback(hal::BluetoothGattInterface* gatt_iface,
                                 int conn_id, int trans_id,
                                 const RawAddress& bda, int exec_write) override;
   void IndicationSentCallback(hal::BluetoothGattInterface* gatt_iface,
                               int conn_id, int status) override;

   // Helper function that notifies and clears the pending callback.
   void CleanUpPendingData();

   // Handles the next attribute entry in the pending service declaration.
   void HandleNextEntry(hal::BluetoothGattInterface* gatt_iface);

   // Helper method that returns a pointer to an internal Connection instance
   // that matches the given parameters.
   std::shared_ptr<Connection> GetConnection(int conn_id, const RawAddress& bda,
                                             int request_id);

   // See getters for documentation.
   Uuid app_identifier_;
   int server_id_;

   // Mutex that synchronizes access to the entries below.
   std::mutex mutex_;
   ResultCallback pending_end_decl_cb_;

   // GATT connection mappings from stack-provided "conn_id" IDs and remote
   // device addresses to Connection structures. The conn_id map is one-to-one
   // while the conn_addr map is one to many, as a remote device may support
   // multiple transports (BR/EDR & LE) and use the same device address for both.
   std::unordered_map<int, std::shared_ptr<Connection>> conn_id_map_;
   std::unordered_map<std::string, std::vector<std::shared_ptr<Connection>>>
       conn_addr_map_;

   // Connections for which a Handle-Value indication is pending. Since there can
   // be multiple indications to the same device (in the case of a dual-mode
   // device with simulatenous BR/EDR & LE GATT connections), we also keep track
   // of whether there has been at least one successful confirmation.
   std::unordered_map<int, std::shared_ptr<PendingIndication>>
       pending_indications_;

   // Raw handle to the Delegate, which must outlive this GattServer instance.
   Delegate* delegate_;

   DISALLOW_COPY_AND_ASSIGN(GattServer);
 };

 // GattServerFactory is used to register and obtain a per-application GattServer
 // instance. Users should call RegisterClient to obtain their own unique
 // GattServer instance that has been registered with the Bluetooth stack.
 class GattServerFactory : public BluetoothInstanceFactory,
                           private hal::BluetoothGattInterface::ServerObserver {
  public:
   // Don't construct/destruct directly except in tests. Instead, obtain a handle
   // from an Adapter instance.
   GattServerFactory();
   ~GattServerFactory() override;

   // BluetoothInstanceFactory override:
   bool RegisterInstance(const Uuid& uuid,
                         const RegisterCallback& callback) override;

  private:
   // hal::BluetoothGattInterface::ServerObserver override:
   void RegisterServerCallback(hal::BluetoothGattInterface* gatt_iface,
                               int status, int server_id,
                               const Uuid& app_uuid) override;

   // Map of pending calls to register.
   std::mutex pending_calls_lock_;
   std::unordered_map<Uuid, RegisterCallback> pending_calls_;

   DISALLOW_COPY_AND_ASSIGN(GattServerFactory);
 };

 }  // namespace bluetooth
	//
	// Copyright 2015 Google, Inc.
	//
	// 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 <deque>
	#include <functional>
	#include <mutex>
	#include <string>
	#include <unordered_map>
	#include <unordered_set>
	#include <vector>

	#include <base/macros.h>
	#include <bluetooth/uuid.h>

	#include "service/bluetooth_instance.h"
	#include "service/common/bluetooth/service.h"
	#include "service/hal/bluetooth_gatt_interface.h"

	namespace bluetooth {

	// A GattServer instance represents an application's handle to perform GATT
	// server-role operations. Instances cannot be created directly and should be
	// obtained through the factory.
	class GattServer : public BluetoothInstance,
	private hal::BluetoothGattInterface::ServerObserver {
	public:
	// Delegate interface is used to handle incoming requests and confirmations
	// for a GATT service.
	class Delegate {
	public:
	Delegate() = default;
	virtual ~Delegate() = default;

	// Called when there is an incoming read request for the characteristic with
	// ID \|characteristic_id\| from a remote device with address
	// \|device_address\|. \|request_id\| can be used to respond to this request by
	// calling SendResponse below.
	virtual void OnCharacteristicReadRequest(GattServer* gatt_server,
	const std::string& device_address,
	int request_id, int offset,
	bool is_long, uint16_t handle) = 0;

	// Called when there is an incoming read request for the descriptor with
	// ID \|descriptor_id\| from a remote device with address \|device_address\|.
	// \|request_id\| can be used to respond to this request by
	// calling SendResponse below.
	virtual void OnDescriptorReadRequest(GattServer* gatt_server,
	const std::string& device_address,
	int request_id, int offset,
	bool is_long, uint16_t handle) = 0;

	// Called when there is an incoming write request for the characteristic
	// with ID \|characteristic_id\| from a remote device with address
	// \|device_address\|. \|request_id\| can be used to respond to this request by
	// calling SendResponse, if the \|need_response\| parameter is true. Otherwise
	// this is a "Write Without Reponse" procedure and SendResponse will fail.
	// If \|is_prepare_write\| is true, then the write should not be committed
	// immediately as this is a "Prepared Write Request". Instead, the Delegate
	// should hold on to the value and either discard it or complete the write
	// when it receives the OnExecuteWriteRequest event.
	virtual void OnCharacteristicWriteRequest(
	GattServer* gatt_server, const std::string& device_address,
	int request_id, int offset, bool is_prepare_write, bool need_response,
	const std::vector<uint8_t>& value, uint16_t handle) = 0;

	// Called when there is an incoming write request for the descriptor
	// with ID \|descriptor_id\| from a remote device with address
	// \|device_address\|. \|request_id\| can be used to respond to this request by
	// calling SendResponse, if the \|need_response\| parameter is true. Otherwise
	// this is a "Write Without Response" procedure and SendResponse will fail.
	// If \|is_prepare_write\| is true, then the write should not be committed
	// immediately as this is a "Prepared Write Request". Instead, the Delegate
	// should hold on to the value and either discard it or complete the write
	// when it receives the OnExecuteWriteRequest event.
	virtual void OnDescriptorWriteRequest(
	GattServer* gatt_server, const std::string& device_address,
	int request_id, int offset, bool is_prepare_write, bool need_response,
	const std::vector<uint8_t>& value, uint16_t handle) = 0;

	// Called when there is an incoming "Execute Write Request". If \|is_execute\|
	// is true, then the Delegate should commit all previously prepared writes.
	// Otherwise, all prepared writes should be aborted. The Delegate should
	// call "SendResponse" to complete the procedure.
	virtual void OnExecuteWriteRequest(GattServer* gatt_server,
	const std::string& device_address,
	int request_id, bool is_execute) = 0;

	virtual void OnConnectionStateChanged(GattServer* gatt_server,
	const std::string& device_addres,
	bool connected) = 0;

	private:
	DISALLOW_COPY_AND_ASSIGN(Delegate);
	};

	// The desctructor automatically unregisters this instance from the stack.
	~GattServer() override;

	// Assigns a delegate to this instance. \|delegate\| must out-live this
	// GattServer instance.
	void SetDelegate(Delegate* delegate);

	// BluetoothClientInstace overrides:
	const Uuid& GetAppIdentifier() const override;
	int GetInstanceId() const override;

	// Callback type used to report the status of an asynchronous GATT server
	// operation.
	using ResultCallback =
	std::function<void(BLEStatus status, const Service& id)>;
	using GattCallback = std::function<void(GATTError error)>;

	// Add service declaration. This method immediately
	// returns false if a service hasn't been started. Otherwise, \|callback\| will
	// be called asynchronously with the result of the operation.
	//
	// TODO(armansito): It is unclear to me what it means for this function to
	// fail. What is the state that we're in? Is the service declaration over so
	// we can add other services to this server instance? Do we need to clean up
	// all the entries or does the upper-layer need to remove the service? Or are
	// we in a stuck-state where the service declaration hasn't ended?
	bool AddService(const Service&, const ResultCallback& callback);

	// Sends a response for a pending notification. \|request_id\| and
	// \|device_address\| should match those that were received through one of the
	// Delegate callbacks. \|value\| and \|offset\| are used for read requests and
	// prepare write requests and should match the value of the attribute. Returns
	// false if the pending request could not be resolved using the given
	// parameters or if the call to the underlying stack fails.
	bool SendResponse(const std::string& device_address, int request_id,
	GATTError error, int offset,
	const std::vector<uint8_t>& value);

	// Sends an ATT Handle-Value Notification to the device with BD_ADDR
	// \|device_address\| for the characteristic with handle \|handle\| and
	// value \|value\|. If \|confirm\| is true, then an ATT Handle-Value Indication
	// will be sent instead, which requires the remote to confirm receipt. Returns
	// false if there was an immediate error in initiating the notification
	// procedure. Otherwise, returns true and reports the asynchronous result of
	// the operation in \|callback\|.
	//
	// If \|confirm\| is true, then \|callback\| will be run when the remote device
	// sends a ATT Handle-Value Confirmation packet. Otherwise, it will be run as
	// soon as the notification has been sent out.
	bool SendNotification(const std::string& device_address,
	const uint16_t handle, bool confirm,
	const std::vector<uint8_t>& value,
	const GattCallback& callback);

	private:
	friend class GattServerFactory;

	// Used for the internal remote connection tracking. Keeps track of the
	// request ID and the device address for the connection. If \|request_id\| is -1
	// then no ATT read/write request is currently pending.
	struct Connection {
	Connection(int conn_id, const RawAddress& bdaddr)
	: conn_id(conn_id), bdaddr(bdaddr) {}
	Connection() : conn_id(-1) { memset(&bdaddr, 0, sizeof(bdaddr)); }

	int conn_id;
	std::unordered_map<int, int> request_id_to_handle;
	RawAddress bdaddr;
	};

	// Used to keep track of a pending Handle-Value indication.
	struct PendingIndication {
	explicit PendingIndication(const GattCallback& callback)
	: has_success(false), callback(callback) {}

	bool has_success;
	GattCallback callback;
	};

	// Constructor shouldn't be called directly as instances are meant to be
	// obtained from the factory.
	GattServer(const Uuid& uuid, int server_id);

	// hal::BluetoothGattInterface::ServerObserver overrides:
	void ConnectionCallback(hal::BluetoothGattInterface* gatt_iface, int conn_id,
	int server_id, int connected,
	const RawAddress& bda) override;
	void ServiceAddedCallback(hal::BluetoothGattInterface* gatt_iface, int status,
	int server_if,
	std::vector<btgatt_db_element_t>) override;
	void ServiceStoppedCallback(hal::BluetoothGattInterface* gatt_iface,
	int status, int server_id,
	int service_handle) override;
	void RequestReadCharacteristicCallback(
	hal::BluetoothGattInterface* gatt_iface, int conn_id, int trans_id,
	const RawAddress& bda, int attribute_handle, int offset,
	bool is_long) override;
	void RequestReadDescriptorCallback(hal::BluetoothGattInterface* gatt_iface,
	int conn_id, int trans_id,
	const RawAddress& bda,
	int attribute_handle, int offset,
	bool is_long) override;
	void RequestWriteCharacteristicCallback(
	hal::BluetoothGattInterface* gatt_iface, int conn_id, int trans_id,
	const RawAddress& bda, int attr_handle, int offset, bool need_rsp,
	bool is_prep, std::vector<uint8_t> value) override;
	void RequestWriteDescriptorCallback(hal::BluetoothGattInterface* gatt_iface,
	int conn_id, int trans_id,
	const RawAddress& bda, int attr_handle,
	int offset, bool need_rsp, bool is_prep,
	std::vector<uint8_t> value) override;
	void RequestExecWriteCallback(hal::BluetoothGattInterface* gatt_iface,
	int conn_id, int trans_id,
	const RawAddress& bda, int exec_write) override;
	void IndicationSentCallback(hal::BluetoothGattInterface* gatt_iface,
	int conn_id, int status) override;

	// Helper function that notifies and clears the pending callback.
	void CleanUpPendingData();

	// Handles the next attribute entry in the pending service declaration.
	void HandleNextEntry(hal::BluetoothGattInterface* gatt_iface);

	// Helper method that returns a pointer to an internal Connection instance
	// that matches the given parameters.
	std::shared_ptr<Connection> GetConnection(int conn_id, const RawAddress& bda,
	int request_id);

	// See getters for documentation.
	Uuid app_identifier_;
	int server_id_;

	// Mutex that synchronizes access to the entries below.
	std::mutex mutex_;
	ResultCallback pending_end_decl_cb_;

	// GATT connection mappings from stack-provided "conn_id" IDs and remote
	// device addresses to Connection structures. The conn_id map is one-to-one
	// while the conn_addr map is one to many, as a remote device may support
	// multiple transports (BR/EDR & LE) and use the same device address for both.
	std::unordered_map<int, std::shared_ptr<Connection>> conn_id_map_;
	std::unordered_map<std::string, std::vector<std::shared_ptr<Connection>>>
	conn_addr_map_;

	// Connections for which a Handle-Value indication is pending. Since there can
	// be multiple indications to the same device (in the case of a dual-mode
	// device with simulatenous BR/EDR & LE GATT connections), we also keep track
	// of whether there has been at least one successful confirmation.
	std::unordered_map<int, std::shared_ptr<PendingIndication>>
	pending_indications_;

	// Raw handle to the Delegate, which must outlive this GattServer instance.
	Delegate* delegate_;

	DISALLOW_COPY_AND_ASSIGN(GattServer);
	};

	// GattServerFactory is used to register and obtain a per-application GattServer
	// instance. Users should call RegisterClient to obtain their own unique
	// GattServer instance that has been registered with the Bluetooth stack.
	class GattServerFactory : public BluetoothInstanceFactory,
	private hal::BluetoothGattInterface::ServerObserver {
	public:
	// Don't construct/destruct directly except in tests. Instead, obtain a handle
	// from an Adapter instance.
	GattServerFactory();
	~GattServerFactory() override;

	// BluetoothInstanceFactory override:
	bool RegisterInstance(const Uuid& uuid,
	const RegisterCallback& callback) override;

	private:
	// hal::BluetoothGattInterface::ServerObserver override:
	void RegisterServerCallback(hal::BluetoothGattInterface* gatt_iface,
	int status, int server_id,
	const Uuid& app_uuid) override;

	// Map of pending calls to register.
	std::mutex pending_calls_lock_;
	std::unordered_map<Uuid, RegisterCallback> pending_calls_;

	DISALLOW_COPY_AND_ASSIGN(GattServerFactory);
	};

	} // namespace bluetooth