mbed-os/features/FEATURE_BLE/ble/GattServer.h

844 lines
28 KiB
C++

/* mbed Microcontroller Library
* Copyright (c) 2006-2013 ARM Limited
*
* 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.
*/
#ifndef MBED_GATT_SERVER_H__
#define MBED_GATT_SERVER_H__
#include "Gap.h"
#include "GattService.h"
#include "GattAttribute.h"
#include "GattServerEvents.h"
#include "GattCallbackParamTypes.h"
#include "CallChainOfFunctionPointersWithContext.h"
/**
* @addtogroup ble
* @{
* @addtogroup gatt
* @{
* @addtogroup server
* @{
*/
/**
* Construct and operates a GATT server.
*
* A Gatt server is a collection of GattService; these services contain
* characteristics that a peer connected to the device may read or write.
* These characteristics may also emit updates to subscribed clients when their
* values change.
*
* @p Server Layout
*
* Application code can add a GattService object to the server with the help of
* the function addService(). That function registers all the GattCharacteristic
* enclosed in the service, as well as all the characteristics descriptors (see
* GattAttribute) these characteristics contain. Service registration assigns
* a unique handle to the various attributes being part of the service; this
* handle should be used for subsequent read or write of these components.
*
* There are no primitives defined to remove a single service; however, a call to
* the function reset() removes all services previously registered in the
* GattServer.
*
* @p Characteristic and attributes access
*
* Values of the characteristic and the characteristic descriptor present in the
* GattServer must be accessed through the handle assigned to them when the service
* has been registered; the GattServer class offers several flavors of read()
* and write() functions that retrieve or mutate an attribute value.
*
* Application code can query if a client has subscribed to a given
* characteristic's value update by invoking the function areUpdatesEnabled().
*
* @p Events
*
* The GattServer allows application code to register several event handlers that
* can be used to monitor client and server activities:
* - onDataSent(): Register an event handler that is called when a
* characteristic value update has been sent to a client.
* - onDataWriten(): Register an event handler that is called when a
* client has written an attribute of the server.
* - onDataRead(): Register an event handler that is called when a
* client has read an attribute of the server.
* - onUpdatesEnabled: Register an event handler that is called when a
* client subscribes to updates of a characteristic.
* - onUpdatesDisabled: Register an event handler that is called when a
* client unsubscribes from updates of a characteristic.
* - onConfimationReceived: Register an event handler that is called
* when a client acknowledges a characteristic value notification.
*
* @note The term characteristic value update is used to represent
* Characteristic Value Notification and Characteristic Value Indication when
* the nature of the server initiated is not relevant.
*/
class GattServer {
public:
/**
* Event handler invoked when the server has sent data to a client.
*
* @see onDataSent().
*/
typedef FunctionPointerWithContext<unsigned> DataSentCallback_t;
/**
* Callchain of DataSentCallback_t objects.
*
* @see onDataSent().
*/
typedef CallChainOfFunctionPointersWithContext<unsigned>
DataSentCallbackChain_t;
/**
* Event handler invoked when the client has written an attribute of the
* server.
*
* @see onDataWritten().
*/
typedef FunctionPointerWithContext<const GattWriteCallbackParams*>
DataWrittenCallback_t;
/**
* Callchain of DataWrittenCallback_t objects.
*
* @see onDataWritten().
*/
typedef CallChainOfFunctionPointersWithContext<const GattWriteCallbackParams*>
DataWrittenCallbackChain_t;
/**
* Event handler invoked when the client has read an attribute of the server.
*
* @see onDataRead().
*/
typedef FunctionPointerWithContext<const GattReadCallbackParams*>
DataReadCallback_t;
/**
* Callchain of DataReadCallback_t.
*
* @see onDataRead().
*/
typedef CallChainOfFunctionPointersWithContext<const GattReadCallbackParams*>
DataReadCallbackChain_t;
/**
* Event handler invoked when the GattServer is reset.
*
* @see onShutdown() reset()
*/
typedef FunctionPointerWithContext<const GattServer *>
GattServerShutdownCallback_t;
/**
* Callchain of GattServerShutdownCallback_t.
*
* @see onShutdown() reset()
*/
typedef CallChainOfFunctionPointersWithContext<const GattServer*>
GattServerShutdownCallbackChain_t;
/**
* Event handler that handles subscription to characteristic updates,
* unsubscription from characteristic updates and notification confirmation.
*
* @see onUpdatesEnabled() onUpdateDisabled() onConfirmationReceived()
*/
typedef FunctionPointerWithContext<GattAttribute::Handle_t> EventCallback_t;
protected:
/**
* Construct a GattServer instance.
*/
GattServer() :
serviceCount(0),
characteristicCount(0),
dataSentCallChain(),
dataWrittenCallChain(),
dataReadCallChain(),
updatesEnabledCallback(NULL),
updatesDisabledCallback(NULL),
confirmationReceivedCallback(NULL) {
}
/*
* The following functions are meant to be overridden in the platform
* specific subclass.
*/
public:
/**
* Add a service declaration to the local attribute server table.
*
* This functions inserts a service declaration in the attribute table
* followed by the characteristic declarations (including characteristic
* descriptors) present in @p service.
*
* The process assigns a unique attribute handle to all the elements added
* into the attribute table. This handle is an ID that must be used for
* subsequent interractions with the elements.
*
* @note There is no mirror function that removes a single service.
* Application code can remove all the registered services by calling
* reset().
*
* @attention Service, characteristics and descriptors objects registered
* within the GattServer must remain reachable until reset() is called.
*
* @param[in] service The service to be added; attribute handle of services,
* characteristic and characteristic descriptors are updated by the
* process.
*
* @return BLE_ERROR_NONE if the service was successfully added.
*/
virtual ble_error_t addService(GattService &service)
{
/* Avoid compiler warnings about unused variables. */
(void)service;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Read the value of an attribute present in the local GATT server.
*
* @param[in] attributeHandle Handle of the attribute to read.
* @param[out] buffer A buffer to hold the value being read.
* @param[in,out] lengthP Length of the buffer being supplied. If the
* attribute value is longer than the size of the supplied buffer, this
* variable holds upon return the total attribute value length (excluding
* offset). The application may use this information to allocate a suitable
* buffer size.
*
* @return BLE_ERROR_NONE if a value was read successfully into the buffer.
*
* @attention read(Gap::Handle_t, GattAttribute::Handle_t, uint8_t *, uint16_t *)
* must be used to read Client Characteristic Configuration Descriptor (CCCD)
* because the value of this type of attribute depends on the connection.
*/
virtual ble_error_t read(
GattAttribute::Handle_t attributeHandle,
uint8_t buffer[],
uint16_t *lengthP
) {
/* Avoid compiler warnings about unused variables. */
(void)attributeHandle;
(void)buffer;
(void)lengthP;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Read the value of an attribute present in the local GATT server.
*
* The connection handle allows application code to read the value of a
* Client Characteristic Configuration Descriptor for a given connection.
*
* @param[in] connectionHandle Connection handle.
* @param[in] attributeHandle Attribute handle for the value attribute of
* the characteristic.
* @param[out] buffer A buffer to hold the value being read.
* @param[in,out] lengthP Length of the buffer being supplied. If the
* attribute value is longer than the size of the supplied buffer, this
* variable holds upon return the total attribute value length (excluding
* offset). The application may use this information to allocate a suitable
* buffer size.
*
* @return BLE_ERROR_NONE if a value was read successfully into the buffer.
*/
virtual ble_error_t read(
Gap::Handle_t connectionHandle,
GattAttribute::Handle_t attributeHandle,
uint8_t *buffer,
uint16_t *lengthP
) {
/* Avoid compiler warnings about unused variables. */
(void)connectionHandle;
(void)attributeHandle;
(void)buffer;
(void)lengthP;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Update the value of an attribute present in the local GATT server.
*
* @param[in] attributeHandle Handle of the attribute to write.
* @param[in] value A pointer to a buffer holding the new value.
* @param[in] size Size in bytes of the new value (in bytes).
* @param[in] localOnly If this flag is false and the attribute handle
* written is a characteristic value, then the server sends an update
* containing the new value to all clients that have subscribed to the
* characteristic's notifications or indications. Otherwise, the update does
* not generate a single server initiated event.
*
* @return BLE_ERROR_NONE if the attribute value has been successfully
* updated.
*/
virtual ble_error_t write(
GattAttribute::Handle_t attributeHandle,
const uint8_t *value,
uint16_t size,
bool localOnly = false
) {
/* Avoid compiler warnings about unused variables. */
(void)attributeHandle;
(void)value;
(void)size;
(void)localOnly;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Update the value of an attribute present in the local GATT server.
*
* The connection handle parameter allows application code to direct
* notification or indication resulting from the update to a specific client.
*
* @param[in] connectionHandle Connection handle.
* @param[in] attributeHandle Handle for the value attribute of the
* characteristic.
* @param[in] value A pointer to a buffer holding the new value.
* @param[in] size Size of the new value (in bytes).
* @param[in] localOnly If this flag is false and the attribute handle
* written is a characteristic value, then the server sends an update
* containing the new value to the client identified by the parameter
* @p connectionHandle if it is subscribed to the characteristic's
* notifications or indications. Otherwise, the update does not generate a
* single server initiated event.
*
* @return BLE_ERROR_NONE if the attribute value has been successfully
* updated.
*/
virtual ble_error_t write(
Gap::Handle_t connectionHandle,
GattAttribute::Handle_t attributeHandle,
const uint8_t *value,
uint16_t size,
bool localOnly = false
) {
/* Avoid compiler warnings about unused variables. */
(void)connectionHandle;
(void)attributeHandle;
(void)value;
(void)size;
(void)localOnly;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Determine if one of the connected clients has subscribed to notifications
* or indications of the characteristic in input.
*
* @param[in] characteristic The characteristic.
* @param[out] enabledP Upon return, *enabledP is true if updates are
* enabled for a connected client; otherwise, *enabledP is false.
*
* @return BLE_ERROR_NONE if the connection and handle are found. False
* otherwise.
*/
virtual ble_error_t areUpdatesEnabled(
const GattCharacteristic &characteristic,
bool *enabledP
) {
/* Avoid compiler warnings about unused variables. */
(void)characteristic;
(void)enabledP;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Determine if an identified client has subscribed to notifications or
* indications of a given characteristic.
*
* @param[in] connectionHandle The connection handle.
* @param[in] characteristic The characteristic.
* @param[out] enabledP Upon return, *enabledP is true if the client
* identified by @p connectionHandle has subscribed to notifications or
* indications of @p characteristic; otherwise, *enabledP is false.
*
* @return BLE_ERROR_NONE if the connection and handle are found. False
* otherwise.
*/
virtual ble_error_t areUpdatesEnabled(
Gap::Handle_t connectionHandle,
const GattCharacteristic &characteristic,
bool *enabledP
) {
/* Avoid compiler warnings about unused variables. */
(void)connectionHandle;
(void)characteristic;
(void)enabledP;
/* Requesting action from porters: override this API if this capability
is supported. */
return BLE_ERROR_NOT_IMPLEMENTED;
}
/**
* Indicate if the underlying stack emit events when an attribute is read by
* a client.
*
* @attention This function should be overridden to return true if
* applicable.
*
* @return true if onDataRead is supported; false otherwise.
*/
virtual bool isOnDataReadAvailable() const
{
/* Requesting action from porters: override this API if this capability
is supported. */
return false;
}
/*
* APIs with nonvirtual implementations.
*/
public:
/**
* Add an event handler that monitors emission of characteristic value
* updates.
*
* @param[in] callback Event handler being registered.
*
* @note It is possible to chain together multiple onDataSent callbacks
* (potentially from different modules of an application).
*/
void onDataSent(const DataSentCallback_t &callback)
{
dataSentCallChain.add(callback);
}
/**
* Add an event handler that monitors emission of characteristic value
* updates.
*
* @param[in] objPtr Pointer to the instance that is used to invoke the
* event handler.
* @param[in] memberPtr Event handler being registered. It is a member
* function.
*/
template <typename T>
void onDataSent(T *objPtr, void (T::*memberPtr)(unsigned count))
{
dataSentCallChain.add(objPtr, memberPtr);
}
/**
* Access the callchain of data sent event handlers.
*
* @return A reference to the DATA_SENT event callback chain.
*/
DataSentCallbackChain_t &onDataSent()
{
return dataSentCallChain;
}
/**
* Set an event handler that is called after
* a connected peer has written an attribute.
*
* @param[in] callback The event handler being registered.
*
* @attention It is possible to set multiple event handlers. Registered
* handlers may be removed with onDataWritten().detach(callback).
*/
void onDataWritten(const DataWrittenCallback_t &callback)
{
dataWrittenCallChain.add(callback);
}
/**
* Set an event handler that is called after
* a connected peer has written an attribute.
*
* @param[in] objPtr Pointer to the instance that is used to invoke the
* event handler (@p memberPtr).
* @param[in] memberPtr Event handler being registered. It is a member
* function.
*/
template <typename T>
void onDataWritten(
T *objPtr,
void (T::*memberPtr)(const GattWriteCallbackParams *context)
) {
dataWrittenCallChain.add(objPtr, memberPtr);
}
/**
* Access the callchain of data written event handlers.
*
* @return A reference to the data written event callbacks chain.
*
* @note It is possible to register callbacks using
* onDataWritten().add(callback).
*
* @note It is possible to unregister callbacks using
* onDataWritten().detach(callback).
*/
DataWrittenCallbackChain_t &onDataWritten()
{
return dataWrittenCallChain;
}
/**
* Set an event handler that monitors attribute reads from connected clients.
*
* @param[in] callback Event handler being registered.
*
* @return BLE_ERROR_NOT_IMPLEMENTED if this functionality isn't available;
* else BLE_ERROR_NONE.
*
* @note This functionality may not be available on all underlying stacks.
* Application code may work around that limitation by monitoring read
* requests instead of read events.
*
* @see GattCharacteristic::setReadAuthorizationCallback()
* @see isOnDataReadAvailable().
*
* @attention It is possible to set multiple event handlers. Registered
* handlers may be removed with onDataRead().detach(callback).
*/
ble_error_t onDataRead(const DataReadCallback_t &callback)
{
if (!isOnDataReadAvailable()) {
return BLE_ERROR_NOT_IMPLEMENTED;
}
dataReadCallChain.add(callback);
return BLE_ERROR_NONE;
}
/**
* Set an event handler that monitors attribute reads from connected clients.
*
* @param[in] objPtr Pointer to the instance that is used to invoke the
* event handler (@p memberPtr).
* @param[in] memberPtr Event handler being registered. It is a member
* function.
*/
template <typename T>
ble_error_t onDataRead(
T *objPtr,
void (T::*memberPtr)(const GattReadCallbackParams *context)
) {
if (!isOnDataReadAvailable()) {
return BLE_ERROR_NOT_IMPLEMENTED;
}
dataReadCallChain.add(objPtr, memberPtr);
return BLE_ERROR_NONE;
}
/**
* Access the callchain of data read event handlers.
*
* @return A reference to the data read event callbacks chain.
*
* @note It is possible to register callbacks using
* onDataRead().add(callback).
*
* @note It is possible to unregister callbacks using
* onDataRead().detach(callback).
*/
DataReadCallbackChain_t &onDataRead()
{
return dataReadCallChain;
}
/**
* Set an event handler that monitors shutdown or reset of the GattServer.
*
* The event handler is invoked when the GattServer instance is about
* to be shut down. This can result in a call to reset() or BLE::reset().
*
* @param[in] callback Event handler being registered.
*
* @note It is possible to set up multiple shutdown event handlers.
*
* @note It is possible to unregister a callback using
* onShutdown().detach(callback)
*/
void onShutdown(const GattServerShutdownCallback_t &callback)
{
shutdownCallChain.add(callback);
}
/**
* Set an event handler that monitors shutdown or reset of the GattServer.
*
* The event handler is invoked when the GattServer instance is about
* to be shut down. This can result of a call to reset() or BLE::reset().
*
* @param[in] objPtr Pointer to the instance that is used to invoke the
* event handler (@p memberPtr).
* @param[in] memberPtr Event handler being registered. It is a member
* function.
*/
template <typename T>
void onShutdown(T *objPtr, void (T::*memberPtr)(const GattServer *))
{
shutdownCallChain.add(objPtr, memberPtr);
}
/**
* Access the callchain of shutdown event handlers.
*
* @return A reference to the shutdown event callbacks chain.
*
* @note It is possible to register callbacks using
* onShutdown().add(callback).
*
* @note It is possible to unregister callbacks using
* onShutdown().detach(callback).
*/
GattServerShutdownCallbackChain_t& onShutdown()
{
return shutdownCallChain;
}
/**
* Set up an event handler that monitors subscription to characteristic
* updates.
*
* @param[in] callback Event handler being registered.
*/
void onUpdatesEnabled(EventCallback_t callback)
{
updatesEnabledCallback = callback;
}
/**
* Set up an event handler that monitors unsubscription from characteristic
* updates.
*
* @param[in] callback Event handler being registered.
*/
void onUpdatesDisabled(EventCallback_t callback)
{
updatesDisabledCallback = callback;
}
/**
* Set up an event handler that monitors notification acknowledgment.
*
* The event handler is called when a client sends a confirmation that it has
* correctly received a notification from the server.
*
* @param[in] callback Event handler being registered.
*/
void onConfirmationReceived(EventCallback_t callback)
{
confirmationReceivedCallback = callback;
}
/* Entry points for the underlying stack to report events back to the user. */
protected:
/**
* Helper function that notifies all registered handlers of an occurrence
* of a data written event.
*
* @attention Vendor implementation must invoke this function after one of
* the GattServer attributes has been written.
*
* @param[in] params The data written parameters passed to the registered
* handlers.
*/
void handleDataWrittenEvent(const GattWriteCallbackParams *params)
{
dataWrittenCallChain.call(params);
}
/**
* Helper function that notifies all registered handlers of an occurrence
* of a data read event.
*
* @attention Vendor implementation must invoke this function after one of
* the GattServer attributes has been read.
*
* @param[in] params The data read parameters passed to the registered
* handlers.
*/
void handleDataReadEvent(const GattReadCallbackParams *params)
{
dataReadCallChain.call(params);
}
/**
* Helper function that notifies the registered handler of an occurrence
* of updates enabled, updates disabled or confirmation received events.
*
* @attention Vendor implementation must invoke this function when a client
* subscribes to characteristic updates, unsubscribes from characteristic
* updates or a notification confirmation has been received.
*
* @param[in] type The type of event that occurred.
* @param[in] attributeHandle The handle of the attribute concerned by the
* event.
*/
void handleEvent(
GattServerEvents::gattEvent_e type,
GattAttribute::Handle_t attributeHandle
) {
switch (type) {
case GattServerEvents::GATT_EVENT_UPDATES_ENABLED:
if (updatesEnabledCallback) {
updatesEnabledCallback(attributeHandle);
}
break;
case GattServerEvents::GATT_EVENT_UPDATES_DISABLED:
if (updatesDisabledCallback) {
updatesDisabledCallback(attributeHandle);
}
break;
case GattServerEvents::GATT_EVENT_CONFIRMATION_RECEIVED:
if (confirmationReceivedCallback) {
confirmationReceivedCallback(attributeHandle);
}
break;
default:
break;
}
}
/**
* Helper function that notifies all registered handlers of an occurrence
* of a data sent event.
*
* @attention Vendor implementation must invoke this function after the
* emission of a notification or an indication.
*
* @param[in] count Number of packets sent.
*/
void handleDataSentEvent(unsigned count)
{
dataSentCallChain.call(count);
}
public:
/**
* Shut down the GattServer instance.
*
* This function notifies all event handlers listening for shutdown events
* that the GattServer is about to be shut down; then it clears all
* GattServer state.
*
* @note This function is meant to be overridden in the platform-specific
* subclass. Overides must call the parent function before any cleanup.
*
* @return BLE_ERROR_NONE on success.
*/
virtual ble_error_t reset(void)
{
/* Notify that the instance is about to shutdown */
shutdownCallChain.call(this);
shutdownCallChain.clear();
serviceCount = 0;
characteristicCount = 0;
dataSentCallChain.clear();
dataWrittenCallChain.clear();
dataReadCallChain.clear();
updatesEnabledCallback = NULL;
updatesDisabledCallback = NULL;
confirmationReceivedCallback = NULL;
return BLE_ERROR_NONE;
}
protected:
/**
* The total number of services added to the ATT table.
*/
uint8_t serviceCount;
/**
* The total number of characteristics added to the ATT table.
*/
uint8_t characteristicCount;
private:
/**
* Callchain containing all registered callback handlers for data sent
* events.
*/
DataSentCallbackChain_t dataSentCallChain;
/**
* Callchain containing all registered callback handlers for data written
* events.
*/
DataWrittenCallbackChain_t dataWrittenCallChain;
/**
* Callchain containing all registered callback handlers for data read
* events.
*/
DataReadCallbackChain_t dataReadCallChain;
/**
* Callchain containing all registered callback handlers for shutdown
* events.
*/
GattServerShutdownCallbackChain_t shutdownCallChain;
/**
* The registered callback handler for updates enabled events.
*/
EventCallback_t updatesEnabledCallback;
/**
* The registered callback handler for updates disabled events.
*/
EventCallback_t updatesDisabledCallback;
/**
* The registered callback handler for confirmation received events.
*/
EventCallback_t confirmationReceivedCallback;
private:
/* Disallow copy and assignment. */
GattServer(const GattServer &);
GattServer& operator=(const GattServer &);
};
/**
* @}
* @}
* @}
*/
#endif /* ifndef MBED_GATT_SERVER_H__ */