esp-nimble-cpp/src/NimBLEDescriptor.cpp

/*
 * NimBLEDescriptor.cpp
 *
 *  Created: on March 10, 2020
 *      Author H2zero
 *
 * Originally:
 *
 * BLEDescriptor.cpp
 *
 *  Created on: Jun 22, 2017
 *      Author: kolban
 */

#include "nimconfig.h"
#if defined(CONFIG_BT_ENABLED) && defined(CONFIG_BT_NIMBLE_ROLE_PERIPHERAL)

#include "NimBLEService.h"
#include "NimBLEDescriptor.h"
#include "NimBLELog.h"

#include <string>

#define NULL_HANDLE (0xffff)

static const char* LOG_TAG = "NimBLEDescriptor";
static NimBLEDescriptorCallbacks defaultCallbacks;


/**
 * @brief Construct a descriptor
 * @param [in] uuid - UUID (const char*) for the descriptor.
 * @param [in] properties - Properties for the descriptor.
 * @param [in] max_len - The maximum length in bytes that the descriptor value can hold. (Default: 512 bytes for esp32, 20 for all others).
 * @param [in] pCharacteristic - pointer to the characteristic instance this descriptor belongs to.
 */
NimBLEDescriptor::NimBLEDescriptor(const char* uuid, uint16_t properties, uint16_t max_len,
                                   NimBLECharacteristic* pCharacteristic)
: NimBLEDescriptor(NimBLEUUID(uuid), properties, max_len, pCharacteristic) {
}


/**
 * @brief Construct a descriptor
 * @param [in] uuid - UUID (const char*) for the descriptor.
 * @param [in] properties - Properties for the descriptor.
 * @param [in] max_len - The maximum length in bytes that the descriptor value can hold. (Default: 512 bytes for esp32, 20 for all others).
 * @param [in] pCharacteristic - pointer to the characteristic instance this descriptor belongs to.
 */
NimBLEDescriptor::NimBLEDescriptor(NimBLEUUID uuid, uint16_t properties, uint16_t max_len,
                                    NimBLECharacteristic* pCharacteristic)
:   m_value(std::min(CONFIG_NIMBLE_CPP_ATT_VALUE_INIT_LENGTH , (int)max_len), max_len) {
    m_uuid               = uuid;
    m_handle             = NULL_HANDLE;                 // Handle is initially unknown.
    m_pCharacteristic    = pCharacteristic;
    m_pCallbacks         = &defaultCallbacks;           // No initial callback.
    m_properties         = 0;
    m_removed            = 0;

    if (properties & BLE_GATT_CHR_F_READ) {             // convert uint16_t properties to uint8_t
        m_properties |= BLE_ATT_F_READ;
    }
    if (properties & (BLE_GATT_CHR_F_WRITE_NO_RSP | BLE_GATT_CHR_F_WRITE)) {
        m_properties |= BLE_ATT_F_WRITE;
    }
    if (properties & BLE_GATT_CHR_F_READ_ENC) {
        m_properties |= BLE_ATT_F_READ_ENC;
    }
    if (properties & BLE_GATT_CHR_F_READ_AUTHEN) {
        m_properties |= BLE_ATT_F_READ_AUTHEN;
    }
    if (properties & BLE_GATT_CHR_F_READ_AUTHOR) {
        m_properties |= BLE_ATT_F_READ_AUTHOR;
    }
    if (properties & BLE_GATT_CHR_F_WRITE_ENC) {
        m_properties |= BLE_ATT_F_WRITE_ENC;
    }
    if (properties & BLE_GATT_CHR_F_WRITE_AUTHEN) {
        m_properties |= BLE_ATT_F_WRITE_AUTHEN;
    }
    if (properties & BLE_GATT_CHR_F_WRITE_AUTHOR) {
        m_properties |= BLE_ATT_F_WRITE_AUTHOR;
    }

} // NimBLEDescriptor


/**
 * @brief NimBLEDescriptor destructor.
 */
NimBLEDescriptor::~NimBLEDescriptor() {
} // ~NimBLEDescriptor

/**
 * @brief Get the BLE handle for this descriptor.
 * @return The handle for this descriptor.
 */
uint16_t NimBLEDescriptor::getHandle() {
    return m_handle;
} // getHandle


/**
 * @brief Get the length of the value of this descriptor.
 * @return The length (in bytes) of the value of this descriptor.
 */
size_t NimBLEDescriptor::getLength() {
    return m_value.size();
} // getLength


/**
 * @brief Get the UUID of the descriptor.
 */
NimBLEUUID NimBLEDescriptor::getUUID() {
    return m_uuid;
} // getUUID


/**
 * @brief Get the value of this descriptor.
 * @return The NimBLEAttValue of this descriptor.
 */
NimBLEAttValue NimBLEDescriptor::getValue(time_t *timestamp) {
    if (timestamp != nullptr) {
        m_value.getValue(timestamp);
    }

    return m_value;
} // getValue


/**
 * @brief Get the value of this descriptor as a string.
 * @return A std::string instance containing a copy of the descriptor's value.
 */
std::string NimBLEDescriptor::getStringValue() {
    return std::string(m_value);
}


/**
 * @brief Get the characteristic this descriptor belongs to.
 * @return A pointer to the characteristic this descriptor belongs to.
 */
NimBLECharacteristic* NimBLEDescriptor::getCharacteristic() {
    return m_pCharacteristic;
} // getCharacteristic


int NimBLEDescriptor::handleGapEvent(uint16_t conn_handle, uint16_t attr_handle,
                                     struct ble_gatt_access_ctxt *ctxt, void *arg) {
    (void)conn_handle;
    (void)attr_handle;

    const ble_uuid_t *uuid;
    int rc;
    NimBLEConnInfo peerInfo;
    NimBLEDescriptor* pDescriptor = (NimBLEDescriptor*)arg;

    NIMBLE_LOGD(LOG_TAG, "Descriptor %s %s event", pDescriptor->getUUID().toString().c_str(),
                                    ctxt->op == BLE_GATT_ACCESS_OP_READ_DSC ? "Read" : "Write");

    uuid = ctxt->chr->uuid;
    if(ble_uuid_cmp(uuid, &pDescriptor->getUUID().getNative()->u) == 0){
        switch(ctxt->op) {
            case BLE_GATT_ACCESS_OP_READ_DSC: {
                rc = ble_gap_conn_find(conn_handle, &peerInfo.m_desc);
                assert(rc == 0);

                 // If the packet header is only 8 bytes this is a follow up of a long read
                 // so we don't want to call the onRead() callback again.
                if(ctxt->om->om_pkthdr_len > 8 ||
                   pDescriptor->m_value.size() <= (ble_att_mtu(peerInfo.getConnHandle()) - 3)) {
                    pDescriptor->m_pCallbacks->onRead(pDescriptor, peerInfo);
                }

                ble_npl_hw_enter_critical();
                rc = os_mbuf_append(ctxt->om, pDescriptor->m_value.data(), pDescriptor->m_value.size());
                ble_npl_hw_exit_critical(0);
                return rc == 0 ? 0 : BLE_ATT_ERR_INSUFFICIENT_RES;
            }

            case BLE_GATT_ACCESS_OP_WRITE_DSC: {
                rc = ble_gap_conn_find(conn_handle, &peerInfo.m_desc);
                assert(rc == 0);

                uint16_t att_max_len = pDescriptor->m_value.max_size();

                if (ctxt->om->om_len > att_max_len) {
                    return BLE_ATT_ERR_INVALID_ATTR_VALUE_LEN;
                }

                uint8_t buf[att_max_len];
                size_t len = ctxt->om->om_len;
                memcpy(buf, ctxt->om->om_data,len);
                os_mbuf *next;
                next = SLIST_NEXT(ctxt->om, om_next);
                while(next != NULL){
                    if((len + next->om_len) > att_max_len) {
                        return BLE_ATT_ERR_INVALID_ATTR_VALUE_LEN;
                    }
                    memcpy(&buf[len], next->om_data, next->om_len);
                    len += next->om_len;
                    next = SLIST_NEXT(next, om_next);
                }

                pDescriptor->setValue(buf, len);
                pDescriptor->m_pCallbacks->onWrite(pDescriptor, peerInfo);
                return 0;
            }
            default:
                break;
        }
    }

    return BLE_ATT_ERR_UNLIKELY;
}

/**
 * @brief Set the callback handlers for this descriptor.
 * @param [in] pCallbacks An instance of a callback structure used to define any callbacks for the descriptor.
 */
void NimBLEDescriptor::setCallbacks(NimBLEDescriptorCallbacks* pCallbacks) {
    if (pCallbacks != nullptr){
        m_pCallbacks = pCallbacks;
    } else {
        m_pCallbacks = &defaultCallbacks;
    }
} // setCallbacks


/**
 * @brief Set the handle of this descriptor.
 * Set the handle of this descriptor to be the supplied value.
 * @param [in] handle The handle to be associated with this descriptor.
 * @return N/A.
 */
void NimBLEDescriptor::setHandle(uint16_t handle) {
    NIMBLE_LOGD(LOG_TAG, ">> setHandle(0x%.2x): Setting descriptor handle to be 0x%.2x", handle, handle);
    m_handle = handle;
    NIMBLE_LOGD(LOG_TAG, "<< setHandle()");
} // setHandle


/**
 * @brief Set the value of the descriptor.
 * @param [in] data The data to set for the descriptor.
 * @param [in] length The length of the data in bytes.
 */
void NimBLEDescriptor::setValue(const uint8_t* data, size_t length) {
    m_value.setValue(data, length);
} // setValue


/**
 * @brief Set the value of the descriptor from a `std::vector<uint8_t>`.\n
 * @param [in] vec The std::vector<uint8_t> reference to set the descriptor value from.
 */
void NimBLEDescriptor::setValue(const std::vector<uint8_t>& vec) {
    return setValue((uint8_t*)&vec[0], vec.size());
} // setValue


/**
 * @brief Set the characteristic this descriptor belongs to.
 * @param [in] pChar A pointer to the characteristic this descriptor belongs to.
 */
void NimBLEDescriptor::setCharacteristic(NimBLECharacteristic* pChar) {
    m_pCharacteristic = pChar;
} // setCharacteristic


/**
 * @brief Return a string representation of the descriptor.
 * @return A string representation of the descriptor.
 */
std::string NimBLEDescriptor::toString() {
    char hex[5];
    snprintf(hex, sizeof(hex), "%04x", m_handle);
    std::string res = "UUID: " + m_uuid.toString() + ", handle: 0x" + hex;
    return res;
} // toString


/**
 * @brief Callback function to support a read request.
 * @param [in] pDescriptor The descriptor that is the source of the event.
 * @param [in] connInfo A reference to a NimBLEConnInfo instance containing the peer info.
 */
void NimBLEDescriptorCallbacks::onRead(NimBLEDescriptor* pDescriptor, NimBLEConnInfo& connInfo) {
    (void)pDescriptor;
    NIMBLE_LOGD("NimBLEDescriptorCallbacks", "onRead: default");
} // onRead


/**
 * @brief Callback function to support a write request.
 * @param [in] pDescriptor The descriptor that is the source of the event.
 * @param [in] connInfo A reference to a NimBLEConnInfo instance containing the peer info.
 */
void NimBLEDescriptorCallbacks::onWrite(NimBLEDescriptor* pDescriptor, NimBLEConnInfo& connInfo) {
    (void)pDescriptor;
    NIMBLE_LOGD("NimBLEDescriptorCallbacks", "onWrite: default");
} // onWrite

#endif /* CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_PERIPHERAL */