Ichthyostega
a0d83b4fe8
This is a design study to find out what would be required to build an opaque function wrapper, similar to `std::function`, yet without using any heap memory ever. Such a building block would allow for some interesting options for a well structured design of elaborate data structures. This changeset provides an implementation draft. __Two important findings to note__: * it is impossible to get away with just a single function pointer * because at the very least we need to invoke the destructor of the embedded delegate. Thus something akin to a "manager" is required. * this implies that the component would not be so efficient as I hoped, since it requires two pointers and requires to emit code for each type of delegate. * by making the component **NonCopyable**, I avoided the complexities of virtual copy support. In case the latter is desired, it would be much simpler to switch to a classical OO approach with a VTable and use our `PolymorphicValue` wrapper to handle copy and cloning.
106 lines
2.9 KiB
C++
106 lines
2.9 KiB
C++
/*
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ThreadWrapperAutonomous(Test) - launching a self-contained and completely detached thread
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Copyright (C)
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2023, Hermann Vosseler <Ichthyostega@web.de>
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**Lumiera** is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2 of the License, or (at your
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option) any later version. See the file COPYING for further details.
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* *****************************************************************/
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/** @file thread-wrapper-autonomous-test.cpp
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** unit test \ref ThreadWrapperAutonomous_test
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*/
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#include "test/run.hpp"
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#include "test/tracking-dummy.hpp"
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#include "lib/thread.hpp"
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#include <atomic>
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#include <chrono>
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using test::Test;
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using test::Dummy;
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using std::atomic_bool;
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using std::this_thread::sleep_for;
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using namespace std::chrono_literals;
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namespace lib {
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namespace test{
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/*******************************************************************//**
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* @test a variation of the Thread wrapper to launch a detached thread,
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* with automatic memory management for the _thread-object._.
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* @see thread.hpp
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* @see ThreadWrapper_test
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*/
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class ThreadWrapperAutonomous_test : public Test
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{
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virtual void
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run (Arg)
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{
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demonstrateSimpleUsage();
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verifyMemoryManagement();
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}
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/** @test demonstrate simply launching a λ-function into background */
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void
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demonstrateSimpleUsage()
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{
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atomic_bool didRun{false};
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launchDetached ("anarchy", [&]{ didRun = true; });
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sleep_for(1ms);
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CHECK (didRun); // verify the effect has taken place
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}
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/**
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* @test verify the detached thread autonomously manages its memory.
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*/
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void
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verifyMemoryManagement()
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{
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struct TestThread
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: ThreadHookable
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{
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using ThreadHookable::ThreadHookable;
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Dummy watcher;
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void
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doIt (int extra)
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{
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watcher.setID (extra);
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sleep_for (5ms);
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}
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};
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// Note the Dummy member allows to watch instance lifecycle
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CHECK (0 == Dummy::checksum());
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launchDetached<TestThread> (&TestThread::doIt, 55);
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CHECK (0 < Dummy::checksum());
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sleep_for (1ms);
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CHECK (55 == Dummy::checksum());
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sleep_for (10ms);
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CHECK (0 == Dummy::checksum());
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}
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};
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/** Register this test class... */
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LAUNCHER (ThreadWrapperAutonomous_test, "function common");
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}} // namespace lib::test
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