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

638 lines
22 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_DISCOVERED_CHARACTERISTIC_H__
#define MBED_DISCOVERED_CHARACTERISTIC_H__
#include "UUID.h"
#include "Gap.h"
#include "GattAttribute.h"
#include "GattClient.h"
#include "CharacteristicDescriptorDiscovery.h"
#include "DiscoveredCharacteristicDescriptor.h"
/**
* @addtogroup ble
* @{
* @addtogroup gatt
* @{
* @addtogroup client
* @{
*/
/**
* Representation of a characteristic discovered.
*
* The GattClient discovery procedure initiated with
* GattClient::launchServiceDiscovery() generates instances of this class.
*
* It exposes the main attributes of the discovered characteristic:
* - The UUID of the characteristic, it can be retrieved by a call to the
* function getUUID(). This UUID is the type of the characteristic.
* - Attribute Handles of the characteristic are present as the triplet
* declaration handle, value handle and last handle. The value handle is
* used to read or write the content of the characteristic.
* - The properties contain the set of operations the characteristic can
* handle, for instance being read or written.
*
* It important to note that the value of the characteristic - if it is
* accessible - is not fetched at discovery time.
*
* The main operations the class offers are reading, writing and discovering
* the descriptors of the characteristic discovered.
*
* Reading a discovered characteristic can be accomplished in two different
* fashions:
*
* If the user has a callback registered for the data read operation in the
* GattClient, then a call to the read(uint16_t) function will initiate a read of
* the characteristic. Results of the operation will be pass on the callback
* registered by GattClient::onDataRead(), which processes all the responses to
* read requests. The read request for a given characteristic can be identified
* by the connection handle and the attribute handle, which are present in
* GattReadCallbackParams.
*
* Another overload (read(uint16_t, const GattClient::ReadCallback_t&)) of the
* read function accepts a completion callback as a last parameter. That
* completion callback will be invoked automatically once the response to the
* read request for that given characteristic has been received. However,
* convenience came at the expense of dynamic memory usage for the time of the
* transaction.
*
* Similarly, two versions of the write() API are exposed. One where the user
* has to register a callback handling write response through the function
* GattClient::onDataWritten() and another one that accepts a completion
* callback in input.
*
* It is also possible to send a write command, which is not acknowledged by the
* peer server by using the function writeWoResponse().
*
* Finally, descriptors of the characteristic can be discovered by invoking the
* function discoverDescriptors, which is shorthand for calling
* GattClient::discoverCharacteristicDescriptors. That discovery is necessary to
* enable or disable characteristic notification or indication that is achieved
* by writing on the Client Characteristic Configuration Descriptor (CCCD).
*/
class DiscoveredCharacteristic {
public:
/**
* Properties of a discovered characteristic.
*/
struct Properties_t {
/**
* Permits broadcasts of the characteristic value using the character
* the Server Characteristic Configuration Descriptor.
*
* @note If set, descriptors of the characteristic contain a Server
* Characteristic Configuration Descriptor.
*/
uint8_t _broadcast :1;
/**
* If set, the value of the characteristic can be read.
*/
uint8_t _read :1;
/**
* If set, a write command can write the characteristic value
* (write without response).
*/
uint8_t _writeWoResp :1;
/**
* If set, clients can issue requests to write the characteristic.
*/
uint8_t _write :1;
/**
* If set, the server can emit notifications of the Characteristic Value
* (without client acknowledgment).
*
* @note If set, descriptors of the characteristic contain a Client
* Characteristic Configuration Descriptor.
*/
uint8_t _notify :1;
/**
* If set, the server can emit indication of the Characteristic Value
* (with client acknowledgement).
*
* @note If set, descriptors of the characteristic contain a Client
* Characteristic Configuration Descriptor.
*/
uint8_t _indicate :1;
/**
* If set, signed write of the Characteristic Value is supported.
*/
uint8_t _authSignedWrite :1;
public:
/**
* Return the value of the broadcast propertie.
*
* @return true if the Server Characteristic Configuration Descriptor
* of the characteristic can be configured to broadcast the
* characteristic value during broadcast procedure.
*
* @see _broadcast
*/
bool broadcast(void) const
{
return _broadcast;
}
/**
* Return the value of the read property
*
* @return true if the characteristic value can be read and false
* otherwise.
*
* @see _read
*/
bool read(void) const
{
return _read;
}
/**
* Return the value of the write without response property.
*
* @return true if the characteristic accepts write without response
* commands and false otherwise.
*
* @see _writeWoResp
*/
bool writeWoResp(void) const
{
return _writeWoResp;
}
/**
* Return the value of the write property.
*
* @return true if writing the characteristic accepts write requests and
* false otherwise.
*
* @see _write
*/
bool write(void) const
{
return _write;
}
/**
* Return the value of the notification property.
*
* @return true if the Client Characteristic Configuration Descriptor
* can be configured to notify the characteristic value to a given
* client and false otherwise.
*
* @note unlike indication, the notification procedure does not require
* acknowledgement from the client.
*
* @see _notify
*/
bool notify(void) const
{
return _notify;
}
/**
* Return the value of the indicate property.
*
* @return true if the Client Characteristic Configuration Descriptor
* can be configured to indicate the characteristic value to a given
* client and false otherwise.
*
* @note unlike notification the indication procedure does require
* acknowledgment from the client.
*
* @see _indicate
*/
bool indicate(void) const
{
return _indicate;
}
/**
* Return the value of the authenticated signed writes property.
*
* @return true if the characteristic accepts authenticated signed write
* and false otherwise.
*/
bool authSignedWrite(void) const
{
return _authSignedWrite;
}
/**
* Equal to operator for DiscoveredCharacteristic::Properties_t.
*
* @param[in] lhs The left hand side of the equality expression.
* @param[in] rhs The right hand side of the equality expression.
*
* @return true if operands are equals and false otherwise.
*/
friend bool operator==(Properties_t lhs, Properties_t rhs)
{
return lhs._broadcast == rhs._broadcast &&
lhs._read == rhs._read &&
lhs._writeWoResp == rhs._writeWoResp &&
lhs._write == rhs._write &&
lhs._notify == rhs._notify &&
lhs._indicate == rhs._indicate &&
lhs._authSignedWrite == rhs._authSignedWrite;
}
/**
* Not equal to operator for DiscoveredCharacteristic::Properties_t.
*
* @param lhs The left hand side of the expression.
* @param rhs The right hand side of the expression.
*
* @return true if operands are not equals, false otherwise.
*/
friend bool operator!=(Properties_t lhs, Properties_t rhs)
{
return !(lhs == rhs);
}
private:
/* Disallow implicit conversion to integer types. */
operator uint8_t() const;
operator unsigned() const;
};
/**
* Initiate a read of the characteristic value.
*
* The characteristic value is read in its entirety from the value attribute
* of the characteristic.
*
* Read responses will be passed to the callback registered in
* GattClient::onDataRead(). Read responses to read requests that this function
* call initiates will have their GattReadCallbackParams::connHandle
* field equal to the value returned by getConnectionHandle() and their
* GattReadCallbackParams::handle field equal to the value returned by
* getValueHandle().
*
* @param[in] offset The position - in the characteristic value bytes stream
* - where the read operation begin. This parameter is optional.
*
* @return BLE_ERROR_NONE if a read has been initiated.
* @return BLE_ERROR_INVALID_STATE if some internal state about the
* connection is invalid.
* @return BLE_STACK_BUSY if some client procedure is already in progress.
* @return BLE_ERROR_OPERATION_NOT_PERMITTED due to the characteristic's
* properties.
*/
ble_error_t read(uint16_t offset = 0) const;
/**
* Initiate a read of the characteristic value and pass the response to its
* completion callback.
*
* @param[in] offset The position - in the characteristic value bytes stream
* - where the read operation begin.
*
* @param[in] onRead Completion callback which will accept the response of
* the read request. The callback is copied; it is unnecessary to keep it
* in memory after the call.
*
* @return BLE_ERROR_NONE if a read has been initiated.
* @return BLE_ERROR_INVALID_STATE if some internal state about the
* connection is invalid.
* @return BLE_STACK_BUSY if some client procedure is already in progress.
* @return BLE_ERROR_OPERATION_NOT_PERMITTED due to the characteristic's
* properties.
*
* @note This function is similar to read(uint16_t) const; however, it uses
* dynamic memory to store the use completion callback.
*/
ble_error_t read(
uint16_t offset,
const GattClient::ReadCallback_t &onRead
) const;
/**
* Perform a write without response procedure.
*
* @note The server does not acknowledge write without responses.
* Therefore, they won't generate any event on the client side.
*
* @param[in] length The amount of data being written.
* @param[in] value The bytes being written.
*
* @return BLE_ERROR_NONE Successfully started the Write procedure.
* @return BLE_ERROR_INVALID_STATE if some internal state about the
* connection is invalid.
* @return BLE_STACK_BUSY if some client procedure is already in progress.
* @return BLE_ERROR_NO_MEM if there are no available buffers left to
* process the request.
* @return BLE_ERROR_OPERATION_NOT_PERMITTED due to the characteristic's
* properties.
*/
ble_error_t writeWoResponse(uint16_t length, const uint8_t *value) const;
/**
* Initiate a discovery of the characteristic descriptors.
*
* When a descriptor is discovered, the callback onDescriptorDiscovered is
* invoked with the descriptor discovered as parameter. When the process
* ends, the callback onTermination is invoked.
*
* @param[in] onDescriptorDiscovered Callback is invoked when a descriptor is
* discovered.
*
* @param[in] onTermination Callback is invoked when the discovery process ends.
*
* @return BLE_ERROR_NONE if descriptor discovery is launched successfully;
* else an appropriate error.
*
* @note This function is shorthand for
* GattClient::discoverCharacteristicDescriptors; therefore,
* GattClient::isCharacteristicDescriptorDiscoveryActive can be used to
* determine the descriptor discovery and
* GattClient::terminateCharacteristicDescriptorDiscovery can be used to
* end the discovery process.
*/
ble_error_t discoverDescriptors(
const CharacteristicDescriptorDiscovery::DiscoveryCallback_t &onDescriptorDiscovered,
const CharacteristicDescriptorDiscovery::TerminationCallback_t &onTermination
) const;
/**
* Initiate a write procedure of the characteristic value.
*
* Unlike write without responses (see writeWoResponse()), an acknowledgment
* is expected for this procedure. The response of the peer GATT server to
* the write request is passed to callbacks registered in
* GattClient::onDataWritten().
*
* Similarly to read responses, responses to write request of this
* characteristic can be identified by their connection handle (
* GattWriteCallbackParams::connHandle), which is equal to the value
* returned by getConnectionHandle() and their attribute handle (
* GattWriteCallbackParams::handle), which is equal to the value
* returned by getValueHandle().
*
* @param[in] length The amount of data being written.
* @param[in] value The bytes being written.
*
* @return BLE_ERROR_NONE Successfully started the Write procedure.
* @return BLE_ERROR_INVALID_STATE If some internal state about the
* connection is invalid.
* @return BLE_STACK_BUSY If some client procedure is already in progress.
* @return BLE_ERROR_NO_MEM If there are no available buffers left to
* process the request.
* @return BLE_ERROR_OPERATION_NOT_PERMITTED due to the characteristic's
* properties.
*
* @note Internally, the API uses the write or long write procedure, depending
* on the number of bytes to write and the MTU size.
*/
ble_error_t write(uint16_t length, const uint8_t *value) const;
/**
* Initiate a write procedure of the characteristic value.
*
* Same as write(uint16_t, const uint8_t *) const but accepts a completion
* callback, which is invoked when the server response is received.
*
* @param[in] length The amount of bytes to write.
* @param[in] value The bytes to write.
* @param[in] onWrite Continuation callback of the write procedure.
*
* @return BLE_ERROR_NONE Successfully started the Write procedure.
* @return BLE_ERROR_INVALID_STATE if some internal state about the
* connection is invalid.
* @return BLE_STACK_BUSY if some client procedure is already in progress.
* @return BLE_ERROR_NO_MEM if there are no available buffers left to
* process the request.
* @return BLE_ERROR_OPERATION_NOT_PERMITTED due to the characteristic's
* properties.
*/
ble_error_t write(
uint16_t length,
const uint8_t *value,
const GattClient::WriteCallback_t &onWrite
) const;
void setupLongUUID(UUID::LongUUIDBytes_t longUUID, UUID::ByteOrder_t order = UUID::MSB) {
uuid.setupLong(longUUID, order);
}
public:
/**
* Get the UUID of the discovered characteristic.
*
* @return The UUID of this characteristic.
*/
const UUID &getUUID(void) const
{
return uuid;
}
/**
* Get the properties of this characteristic.
*
* @return The set of properties of this characteristic.
*/
const Properties_t &getProperties(void) const
{
return props;
}
/**
* Get the declaration handle of this characteristic.
*
* The declaration handle is the first handle of a characteristic
* definition. The value accessible at this handle contains the following
* informations:
* - The characteristics properties (see Properties_t). This value can
* be accessed by using #getProperties .
* - The characteristic value attribute handle. This field can be accessed
* by using #getValueHandle .
* - The characteristic UUID, this value can be accessed by using the
* function #getUUID .
*
* @return the declaration handle of this characteristic.
*/
GattAttribute::Handle_t getDeclHandle(void) const
{
return declHandle;
}
/**
* Get the attribute handle of the characteristic value.
*
* This handle is used to read or write the value of the characteristic.
*
* @return The handle to access the value of this characteristic.
*/
GattAttribute::Handle_t getValueHandle(void) const
{
return valueHandle;
}
/**
* Return the last attribute handle of the characteristic definition.
*
* The attribute layout of a characteristic definition is:
* - Declaration attribute (see #getDeclHandle).
* - Value attribute (see #getValueHandle).
* - Zero or more characteristic descriptors attribute.
*
* The last attribute handle is used internally to discover characteristic
* descriptors. The discovery operates on the range [ValueHandle + 1 :
* LastHandle].
*
* @return The last handle of this characteristic definition.
*
* @note This function is public for informative purposes.
*/
GattAttribute::Handle_t getLastHandle(void) const
{
return lastHandle;
}
/**
* Get the GattClient, which can operate on this characteristic.
*
* @return The GattClient, which can operate on this characteristic.
*/
GattClient* getGattClient()
{
return gattc;
}
/**
* Get the GattClient, which can operate on this characteristic.
*
* @return The GattClient, which can operate on this characteristic.
*/
const GattClient* getGattClient() const
{
return gattc;
}
/**
* @brief Get the connection handle to the GattServer containing this
* characteristic.
*
* @return Connection handle to the GattServer, which contains this
* characteristic.
*/
Gap::Handle_t getConnectionHandle() const
{
return connHandle;
}
/**
* "Equal to" operator for DiscoveredCharacteristic.
*
* @param[in] lhs The left hand side of the equality expression.
* @param[in] rhs The right hand side of the equality expression.
*
* @return true if operands are equals and false otherwise.
*/
friend bool operator==(
const DiscoveredCharacteristic& lhs, const DiscoveredCharacteristic& rhs
) {
return lhs.gattc == rhs.gattc &&
lhs.uuid == rhs.uuid &&
lhs.props == rhs.props &&
lhs.declHandle == rhs.declHandle &&
lhs.valueHandle == rhs.valueHandle &&
lhs.lastHandle == rhs.lastHandle &&
lhs.connHandle == rhs.connHandle;
}
/**
* "Not equal to" operator for DiscoveredCharacteristic.
*
* @param[in] lhs The right hand side of the expression.
* @param[in] rhs The left hand side of the expression.
*
* @return true if operands are not equal and false otherwise.
*/
friend bool operator !=(
const DiscoveredCharacteristic& lhs, const DiscoveredCharacteristic& rhs
) {
return !(lhs == rhs);
}
public:
DiscoveredCharacteristic() :
gattc(NULL),
uuid(UUID::ShortUUIDBytes_t(0)),
props(),
declHandle(GattAttribute::INVALID_HANDLE),
valueHandle(GattAttribute::INVALID_HANDLE),
lastHandle(GattAttribute::INVALID_HANDLE),
connHandle() {
}
protected:
/**
* Pointer to the underlying GattClient for this DiscoveredCharacteristic
* object.
*/
GattClient *gattc;
protected:
/**
* Discovered characteristic's UUID.
*/
UUID uuid;
/**
* Hold the configured properties of the discovered characteristic.
*
* @see Properties_t.
*/
Properties_t props;
/**
* Value handle of the discovered characteristic's declaration attribute.
*/
GattAttribute::Handle_t declHandle;
/**
* Value handle of the discovered characteristic's value attribute.
*/
GattAttribute::Handle_t valueHandle;
/**
* Value handle of the discovered characteristic's last attribute.
*/
GattAttribute::Handle_t lastHandle;
/**
* Handle of the connection where the characteristic was discovered.
*/
Gap::Handle_t connHandle;
};
/**
* @}
* @}
* @}
*/
#endif /*MBED_DISCOVERED_CHARACTERISTIC_H__*/