Line data    Source code

       1             : /*
       2             :  *
       3             :  *    Copyright (c) 2020 Project CHIP Authors
       4             :  *    All rights reserved.
       5             :  *
       6             :  *    Licensed under the Apache License, Version 2.0 (the "License");
       7             :  *    you may not use this file except in compliance with the License.
       8             :  *    You may obtain a copy of the License at
       9             :  *
      10             :  *        http://www.apache.org/licenses/LICENSE-2.0
      11             :  *
      12             :  *    Unless required by applicable law or agreed to in writing, software
      13             :  *    distributed under the License is distributed on an "AS IS" BASIS,
      14             :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      15             :  *    See the License for the specific language governing permissions and
      16             :  *    limitations under the License.
      17             :  */
      18             : 
      19             : /**
      20             :  *    @file
      21             :  *      Definition of a handler for timed interactions.
      22             :  *
      23             :  */
      24             : 
      25             : #pragma once
      26             : 
      27             : #include <messaging/ExchangeContext.h>
      28             : #include <messaging/ExchangeDelegate.h>
      29             : #include <system/SystemClock.h>
      30             : #include <system/SystemLayer.h>
      31             : #include <system/SystemPacketBuffer.h>
      32             : #include <transport/raw/MessageHeader.h>
      33             : 
      34             : /**
      35             :  * A TimedHandler handles a Timed Request action and then waits for a
      36             :  * subsequent Invoke or Write action and hands those on to
      37             :  * InteractionModelEngine if they arrive soon enough.
      38             :  *
      39             :  * Lifetime handling:
      40             :  *
      41             :  * A TimedHandler is initially allocated when the Timed Request is received and
      42             :  * becomes the delegate for that exchange.  After that it remains alive until
      43             :  * either the exchange is closed or the interaction is handed on to the
      44             :  * InteractionModelEngine.
      45             :  */
      46             : 
      47             : namespace chip {
      48             : namespace app {
      49             : 
      50             : class TimedHandler : public Messaging::ExchangeDelegate
      51             : {
      52             : public:
      53           3 :     TimedHandler() {}
      54           3 :     ~TimedHandler() override {}
      55             : 
      56             :     // ExchangeDelegate implementation.
      57             :     CHIP_ERROR OnMessageReceived(Messaging::ExchangeContext * aExchangeContext, const PayloadHeader & aPayloadHeader,
      58             :                                  System::PacketBufferHandle && aPayload) override;
      59             : 
      60             : private:
      61             :     // ExchangeDelegate implementation.
      62           0 :     void OnResponseTimeout(Messaging::ExchangeContext *) override
      63             :     { /* We just want to allow the exchange to close */
      64           0 :     }
      65             :     void OnExchangeClosing(Messaging::ExchangeContext * aExchangeContext) override;
      66             : 
      67             :     void CancelTimer();
      68             : 
      69             :     /**
      70             :      * Handler for the Timed Request action.  This returns success if the Timed
      71             :      * Request action is parsed successfully and the success Status Response
      72             :      * action is sent, failure otherwise.
      73             :      */
      74             :     CHIP_ERROR HandleTimedRequestAction(Messaging::ExchangeContext * aExchangeContext, const PayloadHeader & aPayloadHeader,
      75             :                                         System::PacketBufferHandle && aPayload);
      76             : 
      77             :     enum class State : uint8_t
      78             :     {
      79             :         kExpectingTimedAction,     // Initial state: expecting a timed action.
      80             :         kReceivedTimedAction,      // Have received the timed action.  This can
      81             :                                    // be a terminal state if the action ends up
      82             :                                    // malformed.
      83             :         kExpectingFollowingAction, // Expecting write or invoke.
      84             :     };
      85             : 
      86             :     // Because we have a vtable pointer and mTimeLimit needs to be 8-byte
      87             :     // aligned on ARM, putting mState first here means we fit in 16 bytes on
      88             :     // 32-bit ARM, whereas if we put it second we'd be 24 bytes.
      89             :     // On platforms where either vtable pointers are 8 bytes or 64-bit ints can
      90             :     // be 4-byte-aligned the ordering here does not matter.
      91             :     State mState = State::kExpectingTimedAction;
      92             :     // We keep track of the time limit for message reception, in case our
      93             :     // exchange's "response expected" timer gets delayed and does not fire when
      94             :     // the time runs out.
      95             :     System::Clock::Timestamp mTimeLimit;
      96             : };
      97             : 
      98             : } // namespace app
      99             : } // namespace chip