Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2026 Project CHIP Authors
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : #pragma once
      19              : 
      20              : #include <lib/core/CHIPError.h>
      21              : #include <lib/dnssd/Advertiser.h>
      22              : #include <lib/support/CodeUtils.h>
      23              : #include <lib/support/logging/CHIPLogging.h>
      24              : #include <system/SystemPacketBuffer.h>
      25              : 
      26              : #include <stddef.h>
      27              : 
      28              : namespace chip {
      29              : namespace app {
      30              : 
      31              : /**
      32              :  * @brief Helper class to build TXT record entries for Thread MeshCoP advertisement.
      33              :  */
      34              : class TxtStringsBuilder
      35              : {
      36              : public:
      37            2 :     TxtStringsBuilder() = default;
      38              : 
      39              :     // mNextStart and the mTxtStrings entries point into this object's own mTxtBuffer, so a defaulted
      40              :     // copy would leave them aliasing the source's buffer. The builder is used as a single local and is
      41              :     // never copied; forbid copying so an accidental copy is a compile error rather than a dangling alias.
      42              :     TxtStringsBuilder(const TxtStringsBuilder &)             = delete;
      43              :     TxtStringsBuilder & operator=(const TxtStringsBuilder &) = delete;
      44              : 
      45              :     /**
      46              :      * @brief Fills the TXT record entries from the given advertising parameters.
      47              :      *
      48              :      * @param params The advertising parameters.
      49              :      * @return CHIP_ERROR CHIP_NO_ERROR on success, or CHIP_ERROR_BUFFER_TOO_SMALL if the buffer is too small.
      50              :      */
      51              :     CHIP_ERROR Fill(const Dnssd::CommissionAdvertisingParameters & params);
      52              : 
      53            1 :     size_t GetCount() const { return mCount; }
      54            1 :     const char ** GetEntries() const { return const_cast<const char **>(mTxtStrings); }
      55              : 
      56              : private:
      57              :     CHIP_ERROR FormatAndAdd(const char * format, ...) ENFORCE_FORMAT(2, 3);
      58              : 
      59              :     static constexpr size_t kMaxTxtStringsBuffer = 256;
      60              : 
      61              :     char mTxtBuffer[kMaxTxtStringsBuffer];
      62              :     char * mNextStart = &mTxtBuffer[0];
      63              :     size_t mCount     = 0;
      64              :     const char * mTxtStrings[Dnssd::CommissionAdvertisingParameters::kTxtMaxNumber];
      65              : };
      66              : 
      67              : /**
      68              :  * @brief Builds the Thread Rendezvous Announcement packet buffer.
      69              :  *
      70              :  * @param params The advertising parameters.
      71              :  * @param outBuffer The resulting packet buffer handle.
      72              :  * @return CHIP_ERROR CHIP_NO_ERROR on success, or other error on failure.
      73              :  */
      74              : CHIP_ERROR BuildThreadRendezvousAnnouncement(const Dnssd::CommissionAdvertisingParameters & params,
      75              :                                              System::PacketBufferHandle & outBuffer);
      76              : 
      77              : } // namespace app
      78              : } // namespace chip