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              : /**
      19              :  * @brief defines a generic time source interface that uses a real clock
      20              :  *        at runtime but can be substituted by a test one for unit tests.
      21              :  */
      22              : 
      23              : #pragma once
      24              : 
      25              : #include <lib/support/CodeUtils.h>
      26              : #include <stdlib.h>
      27              : #include <system/SystemClock.h>
      28              : 
      29              : namespace chip {
      30              : namespace Time {
      31              : 
      32              : enum class Source
      33              : {
      34              :     kSystem, // System time source
      35              :     kTest,   // Test time source
      36              : };
      37              : 
      38              : /**
      39              :  * Defines a generic time source within a system. System time and test times
      40              :  * are available.
      41              :  */
      42              : template <Source kSource>
      43              : class TimeSource
      44              : {
      45              : public:
      46              :     /**
      47              :      * Returns a monotonically increasing time in milliseconds since an arbitrary, platform-defined
      48              :      * epoch.
      49              :      *
      50              :      * Maintains requirements for the System::Platform::Layer clock implementation:
      51              :      *
      52              :      *  - Return a value that is ever-increasing (i.e. never * wraps) between reboots of the system.
      53              :      *  - The underlying time source is required to tick continuously during any system sleep modes
      54              :      *    such that the values do not entail a restart upon wake.
      55              :      *  - This function is expected to be thread-safe on any platform that employs threading.
      56              :      */
      57              :     System::Clock::Timestamp GetMonotonicTimestamp();
      58              : };
      59              : 
      60              : /**
      61              :  * A system time source, based on the system platform layer.
      62              :  */
      63              : template <>
      64              : class TimeSource<Source::kSystem>
      65              : {
      66              : public:
      67            1 :     System::Clock::Timestamp GetMonotonicTimestamp() { return System::SystemClock().GetMonotonicTimestamp(); }
      68              : };
      69              : 
      70              : /**
      71              :  * A test time source. Allows setting the current time.
      72              :  */
      73              : template <>
      74              : class TimeSource<Source::kTest>
      75              : {
      76              : public:
      77              :     System::Clock::Timestamp GetMonotonicTimestamp() { return mCurrentTime; }
      78              : 
      79              :     void SetMonotonicTimestamp(System::Clock::Timestamp value)
      80              :     {
      81              :         VerifyOrDie(value >= mCurrentTime);
      82              :         mCurrentTime = value;
      83              :     }
      84              : 
      85              : private:
      86              :     System::Clock::Timestamp mCurrentTime = System::Clock::kZero;
      87              : };
      88              : 
      89              : } // namespace Time
      90              : } // namespace chip