.. _program_listing_file_Test_common_gstreamer_test_support.h:

Program Listing for File gstreamer_test_support.h
=================================================

|exhale_lsh| :ref:`Return to documentation for file <file_Test_common_gstreamer_test_support.h>` (``Test/common/gstreamer_test_support.h``)

.. |exhale_lsh| unicode:: U+021B0 .. UPWARDS ARROW WITH TIP LEFTWARDS

.. code-block:: cpp

   #ifndef KATAGLYPHIS_GSTREAMER_TEST_SUPPORT_H
   #define KATAGLYPHIS_GSTREAMER_TEST_SUPPORT_H
   
   // No includes of its own: include it after the std headers it uses and `import kataglyphis.gstreamer_pipeline;`.
   
   namespace kataglyphis::test {
   
   // The first element GStreamer cannot create, probed through the library itself; empty when all exist.
   inline auto missing_gstreamer_element(std::initializer_list<std::string_view> elements) -> std::string
   {
       if (!kataglyphis::gstreamer::GStreamerPipeline::initialize_gstreamer()) { return "gst_init"; }
       for (const auto element : elements) {
           kataglyphis::gstreamer::GStreamerPipeline probe;
           if (!probe.create_pipeline_from_string(std::string(element))) { return std::string(element); }
       }
       return {};
   }
   
   // Counts events from GStreamer's streaming thread and lets the test thread wait for a total.
   class EventCounter
   {
     public:
       // Notifies under the lock: once the waiter sees the count, add() no longer touches the condition variable.
       void add()
       {
           std::scoped_lock lock(mutex_);
           ++count_;
           changed_.notify_all();
       }
   
       [[nodiscard]] auto wait_for(int expected, std::chrono::milliseconds timeout) -> bool
       {
           std::unique_lock lock(mutex_);
           return changed_.wait_for(lock, timeout, [&] { return count_ >= expected; });
       }
   
       [[nodiscard]] auto count() -> int
       {
           std::scoped_lock lock(mutex_);
           return count_;
       }
   
     private:
       std::mutex mutex_;
       std::condition_variable changed_;
       int count_{ 0 };
   };
   
   // Generous on purpose: the riscv64 lane runs these under QEMU, the Linux lanes under ASan or TSan.
   inline constexpr std::chrono::milliseconds kStreamTimeout{ 60000 };
   
   }// namespace kataglyphis::test
   
   // Skips the running test, naming the element, where this GStreamer install lacks it.
   #define KATAGLYPHIS_REQUIRE_GSTREAMER_ELEMENTS(...)                                                       \
       do {                                                                                                  \
           const auto kataglyphis_missing = ::kataglyphis::test::missing_gstreamer_element({ __VA_ARGS__ }); \
           if (!kataglyphis_missing.empty()) {                                                               \
               GTEST_SKIP() << "GStreamer element '" << kataglyphis_missing << "' is not installed here";    \
           }                                                                                                 \
       } while (false)
   
   #endif// KATAGLYPHIS_GSTREAMER_TEST_SUPPORT_H