Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2020 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 <system/SystemPacketBuffer.h>
      21              : 
      22              : #include <lib/dnssd/minimal_mdns/Query.h>
      23              : #include <lib/dnssd/minimal_mdns/core/DnsHeader.h>
      24              : 
      25              : namespace mdns {
      26              : namespace Minimal {
      27              : 
      28              : class QueryBuilder
      29              : {
      30              : public:
      31              :     QueryBuilder() : mHeader(nullptr) {}
      32           24 :     QueryBuilder(chip::System::PacketBufferHandle && packet) : mHeader(nullptr) { Reset(std::move(packet)); }
      33              : 
      34           24 :     QueryBuilder & Reset(chip::System::PacketBufferHandle && packet)
      35              :     {
      36           24 :         mPacket = std::move(packet);
      37           24 :         mHeader = HeaderRef(mPacket->Start());
      38              : 
      39           24 :         if (mPacket->AvailableDataLength() >= HeaderRef::kSizeBytes)
      40              :         {
      41           24 :             mPacket->SetDataLength(HeaderRef::kSizeBytes);
      42           24 :             mHeader.Clear();
      43              :         }
      44              :         else
      45              :         {
      46            0 :             mQueryBuildOk = false;
      47              :         }
      48              : 
      49           24 :         mHeader.SetFlags(mHeader.GetFlags().SetQuery());
      50           24 :         return *this;
      51              :     }
      52              : 
      53              :     CHECK_RETURN_VALUE
      54           24 :     chip::System::PacketBufferHandle && ReleasePacket()
      55              :     {
      56           24 :         mHeader       = HeaderRef(nullptr);
      57           24 :         mQueryBuildOk = false;
      58           24 :         return std::move(mPacket);
      59              :     }
      60              : 
      61           24 :     HeaderRef & Header() { return mHeader; }
      62              : 
      63           24 :     QueryBuilder & AddQuery(const Query & query)
      64              :     {
      65           24 :         if (!mQueryBuildOk)
      66              :         {
      67            0 :             return *this;
      68              :         }
      69              : 
      70           24 :         chip::Encoding::BigEndian::BufferWriter out(mPacket->Start() + mPacket->DataLength(), mPacket->AvailableDataLength());
      71           24 :         RecordWriter writer(&out);
      72              : 
      73           24 :         if (!query.Append(mHeader, writer))
      74              :         {
      75            0 :             mQueryBuildOk = false;
      76              :         }
      77              :         else
      78              :         {
      79           24 :             mPacket->SetDataLength(static_cast<uint16_t>(mPacket->DataLength() + out.Needed()));
      80              :         }
      81           24 :         return *this;
      82              :     }
      83              : 
      84            0 :     bool Ok() const { return mQueryBuildOk; }
      85              : 
      86              : private:
      87              :     chip::System::PacketBufferHandle mPacket;
      88              :     HeaderRef mHeader;
      89              :     bool mQueryBuildOk = true;
      90              : };
      91              : 
      92              : } // namespace Minimal
      93              : } // namespace mdns