NimBLERemoteValueAttribute.h

/*
 * Copyright 2020-2025 Ryan Powell <ryan@nable-embedded.io> and
 * esp-nimble-cpp, NimBLE-Arduino contributors.
 *
 * 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 NIMBLE_CPP_REMOTE_VALUE_ATTRIBUTE_H_
#define NIMBLE_CPP_REMOTE_VALUE_ATTRIBUTE_H_
 
#include "nimconfig.h"
#if CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_CENTRAL
 
# if defined(CONFIG_NIMBLE_CPP_IDF)
#  include <host/ble_gatt.h>
# else
#  include <nimble/nimble/host/include/host/ble_gatt.h>
# endif
 
/****  FIX COMPILATION ****/
# undef min
# undef max
/**************************/
 
# include "NimBLEValueAttribute.h"
# include "NimBLEAttValue.h"
 
class NimBLEClient;
 
class NimBLERemoteValueAttribute : public NimBLEValueAttribute, public NimBLEAttribute {
  public:
    NimBLEAttValue readValue(time_t* timestamp = nullptr);
 
    virtual NimBLEClient* getClient() const = 0;
 
    bool writeValue(const uint8_t* data, size_t length, bool response = false) const;
 
    bool writeValue(const char* str, size_t length = 0, bool response = false) const {
        return writeValue(reinterpret_cast<const uint8_t*>(str), length ? length : strlen(str), response);
    }
 
# if __cplusplus < 201703L
    template <typename T>
#  ifdef _DOXYGEN_
    bool
#  else
    typename std::enable_if<!std::is_pointer<T>::value && !Has_c_str_length<T>::value && !Has_data_size<T>::value, bool>::type
#  endif
    writeValue(const T& v, bool response = false) const {
        return writeValue(reinterpret_cast<const uint8_t*>(&v), sizeof(T), response);
    }
 
    template <typename T>
#  ifdef _DOXYGEN_
    bool
#  else
    typename std::enable_if<Has_c_str_length<T>::value && !Has_data_size<T>::value, bool>::type
#  endif
    writeValue(const T& s, bool response = false) const {
        return writeValue(reinterpret_cast<const uint8_t*>(s.c_str()), s.length(), response);
    }
 
    template <typename T>
#  ifdef _DOXYGEN_
    bool
#  else
    typename std::enable_if<Has_data_size<T>::value && Has_value_type<T>::value, bool>::type
#  endif
    writeValue(const T& v, bool response = false) const {
        return writeValue(
            reinterpret_cast<const uint8_t*>(v.data()),
            v.size() * sizeof(typename T::value_type),
            response
        );
    }
 
    template <typename T>
#  ifdef _DOXYGEN_
    bool
#  else
    typename std::enable_if<Has_data_size<T>::value && !Has_value_type<T>::value, bool>::type
#  endif
    writeValue(const T& v, bool response = false) const {
        return writeValue(reinterpret_cast<const uint8_t*>(v.data()), v.size(), response);
    }
 
# else
    template <typename T>
    typename std::enable_if<!std::is_pointer<T>::value, bool>::type writeValue(const T& v, bool response = false) const {
        if constexpr (Has_data_size<T>::value) {
            if constexpr (Has_value_type<T>::value) {
                return writeValue(reinterpret_cast<const uint8_t*>(v.data()), v.size() * sizeof(typename T::value_type), response);
            } else {
                return writeValue(reinterpret_cast<const uint8_t*>(v.data()), v.size(), response);
            }
        } else if constexpr (Has_c_str_length<T>::value) {
            return writeValue(reinterpret_cast<const uint8_t*>(v.c_str()), v.length(), response);
        } else {
            return writeValue(reinterpret_cast<const uint8_t*>(&v), sizeof(v), response);
        }
    }
# endif
 
    template <typename T>
    T readValue(time_t* timestamp = nullptr, bool skipSizeCheck = false) {
        readValue();
        return getValue<T>(timestamp, skipSizeCheck);
    }
 
  protected:
    NimBLERemoteValueAttribute(const ble_uuid_any_t& uuid, uint16_t handle) : NimBLEAttribute{uuid, handle} {}
 
    virtual ~NimBLERemoteValueAttribute() = default;
 
    static int onReadCB(uint16_t conn_handle, const ble_gatt_error* error, ble_gatt_attr* attr, void* arg);
    static int onWriteCB(uint16_t conn_handle, const ble_gatt_error* error, ble_gatt_attr* attr, void* arg);
};
 
#endif // CONFIG_BT_ENABLED && CONFIG_BT_NIMBLE_ROLE_CENTRAL
#endif // NIMBLE_CPP_REMOTE_VALUE_ATTRIBUTE_H_