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           0 :     QueryBuilder(chip::System::PacketBufferHandle && packet) : mHeader(nullptr) { Reset(std::move(packet)); }
      33             : 
      34           0 :     QueryBuilder & Reset(chip::System::PacketBufferHandle && packet)
      35             :     {
      36           0 :         mPacket = std::move(packet);
      37           0 :         mHeader = HeaderRef(mPacket->Start());
      38             : 
      39           0 :         if (mPacket->AvailableDataLength() >= HeaderRef::kSizeBytes)
      40             :         {
      41           0 :             mPacket->SetDataLength(HeaderRef::kSizeBytes);
      42           0 :             mHeader.Clear();
      43             :         }
      44             :         else
      45             :         {
      46           0 :             mQueryBuildOk = false;
      47             :         }
      48             : 
      49           0 :         mHeader.SetFlags(mHeader.GetFlags().SetQuery());
      50           0 :         return *this;
      51             :     }
      52             : 
      53             :     CHECK_RETURN_VALUE
      54           0 :     chip::System::PacketBufferHandle && ReleasePacket()
      55             :     {
      56           0 :         mHeader       = HeaderRef(nullptr);
      57           0 :         mQueryBuildOk = false;
      58           0 :         return std::move(mPacket);
      59             :     }
      60             : 
      61           0 :     HeaderRef & Header() { return mHeader; }
      62             : 
      63           0 :     QueryBuilder & AddQuery(const Query & query)
      64             :     {
      65           0 :         if (!mQueryBuildOk)
      66             :         {
      67           0 :             return *this;
      68             :         }
      69             : 
      70           0 :         chip::Encoding::BigEndian::BufferWriter out(mPacket->Start() + mPacket->DataLength(), mPacket->AvailableDataLength());
      71           0 :         RecordWriter writer(&out);
      72             : 
      73           0 :         if (!query.Append(mHeader, writer))
      74             :         {
      75           0 :             mQueryBuildOk = false;
      76             :         }
      77             :         else
      78             :         {
      79           0 :             mPacket->SetDataLength(static_cast<uint16_t>(mPacket->DataLength() + out.Needed()));
      80             :         }
      81           0 :         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